channelmonitor.rs

// This file is Copyright its original authors, visible in version control
// history.
//
// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
// You may not use this file except in accordance with one or both of these
// licenses.

//! The logic to monitor for on-chain transactions and create the relevant claim responses lives
//! here.
//!
//! ChannelMonitor objects are generated by ChannelManager in response to relevant
//! messages/actions, and MUST be persisted to disk (and, preferably, remotely) before progress can
//! be made in responding to certain messages, see [`chain::Watch`] for more.
//!
//! Note that ChannelMonitors are an important part of the lightning trust model and a copy of the
//! latest ChannelMonitor must always be actively monitoring for chain updates (and no out-of-date
//! ChannelMonitors should do so). Thus, if you're building rust-lightning into an HSM or other
//! security-domain-separated system design, you should consider having multiple paths for
//! ChannelMonitors to get out of the HSM and onto monitoring devices.

use bitcoin::amount::Amount;
use bitcoin::block::Header;
use bitcoin::script::{Script, ScriptBuf};
use bitcoin::transaction::{OutPoint as BitcoinOutPoint, Transaction, TxOut};

use bitcoin::hash_types::{BlockHash, Txid};
use bitcoin::hashes::sha256::Hash as Sha256;
use bitcoin::hashes::Hash;

use bitcoin::ecdsa::Signature as BitcoinSignature;
use bitcoin::secp256k1::{self, ecdsa::Signature, PublicKey, Secp256k1, SecretKey};

use crate::chain;
use crate::chain::chaininterface::{
	BroadcasterInterface, ConfirmationTarget, FeeEstimator, LowerBoundedFeeEstimator,
};
use crate::chain::onchaintx::{ClaimEvent, FeerateStrategy, OnchainTxHandler};
use crate::chain::package::{
	CounterpartyOfferedHTLCOutput, CounterpartyReceivedHTLCOutput, HolderFundingOutput,
	HolderHTLCOutput, PackageSolvingData, PackageTemplate, RevokedHTLCOutput, RevokedOutput,
};
use crate::chain::transaction::{OutPoint, TransactionData};
use crate::chain::{BestBlock, WatchedOutput};
use crate::events::bump_transaction::{AnchorDescriptor, BumpTransactionEvent};
use crate::events::{ClosureReason, Event, EventHandler, ReplayEvent};
use crate::ln::chan_utils::{
	self, ChannelTransactionParameters, CommitmentTransaction, CounterpartyCommitmentSecrets,
	HTLCClaim, HTLCOutputInCommitment, HolderCommitmentTransaction,
};
use crate::ln::channel::INITIAL_COMMITMENT_NUMBER;
use crate::ln::channel_keys::{
	DelayedPaymentBasepoint, DelayedPaymentKey, HtlcBasepoint, HtlcKey, RevocationBasepoint,
	RevocationKey,
};
use crate::ln::channelmanager::{HTLCSource, PaymentClaimDetails, SentHTLCId};
use crate::ln::msgs::DecodeError;
use crate::ln::types::ChannelId;
use crate::sign::{
	ecdsa::EcdsaChannelSigner, ChannelDerivationParameters, DelayedPaymentOutputDescriptor,
	EntropySource, HTLCDescriptor, SignerProvider, SpendableOutputDescriptor,
	StaticPaymentOutputDescriptor,
};
use crate::types::features::ChannelTypeFeatures;
use crate::types::payment::{PaymentHash, PaymentPreimage};
use crate::util::byte_utils;
use crate::util::logger::{Logger, WithContext};
use crate::util::persist::MonitorName;
use crate::util::ser::{
	MaybeReadable, Readable, ReadableArgs, RequiredWrapper, UpgradableRequired, Writeable, Writer,
	U48,
};

#[allow(unused_imports)]
use crate::prelude::*;

use crate::io::{self, Error};
use crate::sync::Mutex;
use core::ops::Deref;
use core::{cmp, mem};

/// An update generated by the underlying channel itself which contains some new information the
/// [`ChannelMonitor`] should be made aware of.
///
/// Because this represents only a small number of updates to the underlying state, it is generally
/// much smaller than a full [`ChannelMonitor`]. However, for large single commitment transaction
/// updates (e.g. ones during which there are hundreds of HTLCs pending on the commitment
/// transaction), a single update may reach upwards of 1 MiB in serialized size.
#[derive(Clone, Debug, PartialEq, Eq)]
#[must_use]
pub struct ChannelMonitorUpdate {
	pub(crate) updates: Vec<ChannelMonitorUpdateStep>,
	/// The sequence number of this update. Updates *must* be replayed in-order according to this
	/// sequence number (and updates may panic if they are not). The update_id values are strictly
	/// increasing and increase by one for each new update, with two exceptions specified below.
	///
	/// This sequence number is also used to track up to which points updates which returned
	/// [`ChannelMonitorUpdateStatus::InProgress`] have been applied to all copies of a given
	/// ChannelMonitor when ChannelManager::channel_monitor_updated is called.
	///
	/// Note that for [`ChannelMonitorUpdate`]s generated on LDK versions prior to 0.1 after the
	/// channel was closed, this value may be [`u64::MAX`]. In that case, multiple updates may
	/// appear with the same ID, and all should be replayed.
	///
	/// [`ChannelMonitorUpdateStatus::InProgress`]: super::ChannelMonitorUpdateStatus::InProgress
	pub update_id: u64,
	/// The channel ID associated with these updates.
	///
	/// Will be `None` for `ChannelMonitorUpdate`s constructed on LDK versions prior to 0.0.121 and
	/// always `Some` otherwise.
	pub channel_id: Option<ChannelId>,
}

impl ChannelMonitorUpdate {
	pub(crate) fn internal_renegotiated_funding_data(
		&self,
	) -> impl Iterator<Item = (OutPoint, ScriptBuf)> + '_ {
		self.updates.iter().filter_map(|update| match update {
			ChannelMonitorUpdateStep::RenegotiatedFunding { channel_parameters, .. } => {
				let funding_outpoint = channel_parameters
					.funding_outpoint
					.expect("Renegotiated funding must always have known outpoint");
				let funding_script = channel_parameters.make_funding_redeemscript().to_p2wsh();
				Some((funding_outpoint, funding_script))
			},
			_ => None,
		})
	}

	/// Returns a `Vec` of new (funding outpoint, funding script) to monitor the chain for as a
	/// result of a renegotiated funding transaction.
	#[cfg(c_bindings)]
	pub fn renegotiated_funding_data(&self) -> Vec<(OutPoint, ScriptBuf)> {
		self.internal_renegotiated_funding_data().collect()
	}

	/// Returns an iterator of new (funding outpoint, funding script) to monitor the chain for as a
	/// result of a renegotiated funding transaction.
	#[cfg(not(c_bindings))]
	pub fn renegotiated_funding_data(&self) -> impl Iterator<Item = (OutPoint, ScriptBuf)> + '_ {
		self.internal_renegotiated_funding_data()
	}
}

/// LDK prior to 0.1 used this constant as the [`ChannelMonitorUpdate::update_id`] for any
/// [`ChannelMonitorUpdate`]s which were generated after the channel was closed.
const LEGACY_CLOSED_CHANNEL_UPDATE_ID: u64 = u64::MAX;

impl Writeable for ChannelMonitorUpdate {
	fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
		write_ver_prefix!(w, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
		self.update_id.write(w)?;
		(self.updates.len() as u64).write(w)?;
		for update_step in self.updates.iter() {
			update_step.write(w)?;
		}
		write_tlv_fields!(w, {
			// 1 was previously used to store `counterparty_node_id`
			(3, self.channel_id, option),
		});
		Ok(())
	}
}
impl Readable for ChannelMonitorUpdate {
	#[rustfmt::skip]
	fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
		let _ver = read_ver_prefix!(r, SERIALIZATION_VERSION);
		let update_id: u64 = Readable::read(r)?;
		let len: u64 = Readable::read(r)?;
		let mut updates = Vec::with_capacity(cmp::min(len as usize, MAX_ALLOC_SIZE / ::core::mem::size_of::<ChannelMonitorUpdateStep>()));
		for _ in 0..len {
			if let Some(upd) = MaybeReadable::read(r)? {
				updates.push(upd);
			}
		}
		let mut channel_id = None;
		read_tlv_fields!(r, {
			// 1 was previously used to store `counterparty_node_id`
			(3, channel_id, option),
		});
		Ok(Self { update_id, updates, channel_id })
	}
}

/// An event to be processed by the ChannelManager.
#[derive(Clone, PartialEq, Eq)]
pub enum MonitorEvent {
	/// A monitor event containing an HTLCUpdate.
	HTLCEvent(HTLCUpdate),

	/// Indicates we broadcasted the channel's latest commitment transaction and thus closed the
	/// channel. Holds information about the channel and why it was closed.
	HolderForceClosedWithInfo {
		/// The reason the channel was closed.
		reason: ClosureReason,
		/// The funding outpoint of the channel.
		outpoint: OutPoint,
		/// The channel ID of the channel.
		channel_id: ChannelId,
	},

	/// Indicates we broadcasted the channel's latest commitment transaction and thus closed the
	/// channel.
	HolderForceClosed(OutPoint),

	/// Indicates that we've detected a commitment transaction (either holder's or counterparty's)
	/// be included in a block and should consider the channel closed.
	CommitmentTxConfirmed(()),

	/// Indicates a [`ChannelMonitor`] update has completed. See
	/// [`ChannelMonitorUpdateStatus::InProgress`] for more information on how this is used.
	///
	/// [`ChannelMonitorUpdateStatus::InProgress`]: super::ChannelMonitorUpdateStatus::InProgress
	Completed {
		/// The funding outpoint of the [`ChannelMonitor`] that was updated
		funding_txo: OutPoint,
		/// The channel ID of the channel associated with the [`ChannelMonitor`]
		channel_id: ChannelId,
		/// The Update ID from [`ChannelMonitorUpdate::update_id`] which was applied or
		/// [`ChannelMonitor::get_latest_update_id`].
		///
		/// Note that this should only be set to a given update's ID if all previous updates for the
		/// same [`ChannelMonitor`] have been applied and persisted.
		monitor_update_id: u64,
	},
}
impl_writeable_tlv_based_enum_upgradable_legacy!(MonitorEvent,
	// Note that Completed is currently never serialized to disk as it is generated only in
	// ChainMonitor.
	(0, Completed) => {
		(0, funding_txo, required),
		(2, monitor_update_id, required),
		(4, channel_id, required),
	},
	(5, HolderForceClosedWithInfo) => {
		(0, reason, upgradable_required),
		(2, outpoint, required),
		(4, channel_id, required),
	},
;
	(1, CommitmentTxConfirmed),
	(2, HTLCEvent),
	(4, HolderForceClosed),
	// 6 was `UpdateFailed` until LDK 0.0.117
);

/// Simple structure sent back by `chain::Watch` when an HTLC from a forward channel is detected on
/// chain. Used to update the corresponding HTLC in the backward channel. Failing to pass the
/// preimage claim backward will lead to loss of funds.
#[derive(Clone, PartialEq, Eq)]
pub struct HTLCUpdate {
	pub(crate) payment_hash: PaymentHash,
	pub(crate) payment_preimage: Option<PaymentPreimage>,
	pub(crate) source: HTLCSource,
	pub(crate) htlc_value_satoshis: Option<u64>,
}
impl_writeable_tlv_based!(HTLCUpdate, {
	(0, payment_hash, required),
	(1, htlc_value_satoshis, option),
	(2, source, required),
	(4, payment_preimage, option),
});

/// If an output goes from claimable only by us to claimable by us or our counterparty within this
/// many blocks, we consider it pinnable for the purposes of aggregating claims in a single
/// transaction.
pub(crate) const COUNTERPARTY_CLAIMABLE_WITHIN_BLOCKS_PINNABLE: u32 = 12;

/// When we go to force-close a channel because an HTLC is expiring, by the time we've gotten the
/// commitment transaction confirmed, we should ensure that the HTLC(s) expiring are not considered
/// pinnable, allowing us to aggregate them with other HTLC(s) expiring at the same time.
const _: () = assert!(MAX_BLOCKS_FOR_CONF > COUNTERPARTY_CLAIMABLE_WITHIN_BLOCKS_PINNABLE);

/// The upper bound on how many blocks we think it can take for us to get a transaction confirmed.
pub(crate) const MAX_BLOCKS_FOR_CONF: u32 = 18;

/// If an HTLC expires within this many blocks, force-close the channel to broadcast the
/// HTLC-Success transaction.
///
/// This is two times [`MAX_BLOCKS_FOR_CONF`] as we need to first get the commitment transaction
/// confirmed, then get an HTLC transaction confirmed.
pub(crate) const CLTV_CLAIM_BUFFER: u32 = MAX_BLOCKS_FOR_CONF * 2;
/// Number of blocks by which point we expect our counterparty to have seen new blocks on the
/// network and done a full update_fail_htlc/commitment_signed dance (+ we've updated all our
/// copies of ChannelMonitors, including watchtowers). We could enforce the contract by failing
/// at CLTV expiration height but giving a grace period to our peer may be profitable for us if he
/// can provide an over-late preimage. Nevertheless, grace period has to be accounted in our
/// CLTV_EXPIRY_DELTA to be secure. Following this policy we may decrease the rate of channel failures
/// due to expiration but increase the cost of funds being locked longuer in case of failure.
/// This delay also cover a low-power peer being slow to process blocks and so being behind us on
/// accurate block height.
/// In case of onchain failure to be pass backward we may see the last block of ANTI_REORG_DELAY
/// with at worst this delay, so we are not only using this value as a mercy for them but also
/// us as a safeguard to delay with enough time.
pub(crate) const LATENCY_GRACE_PERIOD_BLOCKS: u32 = 3;
/// Number of blocks we wait on seeing a HTLC output being solved before we fail corresponding
/// inbound HTLCs. This prevents us from failing backwards and then getting a reorg resulting in us
/// losing money.
///
/// Note that this is a library-wide security assumption. If a reorg deeper than this number of
/// blocks occurs, counterparties may be able to steal funds or claims made by and balances exposed
/// by a  [`ChannelMonitor`] may be incorrect.
// We also use this delay to be sure we can remove our in-flight claim txn from bump candidates buffer.
// It may cause spurious generation of bumped claim txn but that's alright given the outpoint is already
// solved by a previous claim tx. What we want to avoid is reorg evicting our claim tx and us not
// keep bumping another claim tx to solve the outpoint.
pub const ANTI_REORG_DELAY: u32 = 6;
/// Number of blocks we wait before assuming a [`ChannelMonitor`] to be fully resolved and
/// considering it be safely archived.
// 4032 blocks are roughly four weeks
pub const ARCHIVAL_DELAY_BLOCKS: u32 = 4032;
/// Number of blocks before confirmation at which we fail back an un-relayed HTLC or at which we
/// refuse to accept a new HTLC.
///
/// This is used for a few separate purposes:
/// 1) if we've received an MPP HTLC to us and it expires within this many blocks and we are
///    waiting on additional parts (or waiting on the preimage for any HTLC from the user), we will
///    fail this HTLC,
/// 2) if we receive an HTLC within this many blocks of its expiry (plus one to avoid a race
///    condition with the above), we will fail this HTLC without telling the user we received it,
///
/// (1) is all about protecting us - we need enough time to update the channel state before we hit
/// CLTV_CLAIM_BUFFER, at which point we'd go on chain to claim the HTLC with the preimage.
///
/// (2) is the same, but with an additional buffer to avoid accepting an HTLC which is immediately
/// in a race condition between the user connecting a block (which would fail it) and the user
/// providing us the preimage (which would claim it).
pub const HTLC_FAIL_BACK_BUFFER: u32 = CLTV_CLAIM_BUFFER + LATENCY_GRACE_PERIOD_BLOCKS;

// Deprecated, use [`HolderCommitment`] or [`HolderCommitmentTransaction`].
#[derive(Clone, PartialEq, Eq)]
struct HolderSignedTx {
	/// txid of the transaction in tx, just used to make comparison faster
	txid: Txid,
	revocation_key: RevocationKey,
	a_htlc_key: HtlcKey,
	b_htlc_key: HtlcKey,
	delayed_payment_key: DelayedPaymentKey,
	per_commitment_point: PublicKey,
	htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Signature>, Option<HTLCSource>)>,
	to_self_value_sat: u64,
	feerate_per_kw: u32,
}

// Any changes made here must also reflect in `write_legacy_holder_commitment_data`.
impl_writeable_tlv_based!(HolderSignedTx, {
	(0, txid, required),
	(1, to_self_value_sat, required), // Added in 0.0.100, required in 0.2.
	(2, revocation_key, required),
	(4, a_htlc_key, required),
	(6, b_htlc_key, required),
	(8, delayed_payment_key, required),
	(10, per_commitment_point, required),
	(12, feerate_per_kw, required),
	(14, htlc_outputs, required_vec)
});

// Matches the serialization of `HolderSignedTx` for backwards compatibility reasons.
#[rustfmt::skip]
fn write_legacy_holder_commitment_data<W: Writer>(
	writer: &mut W, commitment_tx: &HolderCommitmentTransaction, htlc_data: &CommitmentHTLCData,
) -> Result<(), io::Error> {
	let trusted_tx = commitment_tx.trust();
	let tx_keys = trusted_tx.keys();

	let txid = trusted_tx.txid();
	let to_self_value_sat = commitment_tx.to_broadcaster_value_sat();
	let feerate_per_kw = trusted_tx.negotiated_feerate_per_kw();
	let revocation_key = &tx_keys.revocation_key;
	let a_htlc_key = &tx_keys.broadcaster_htlc_key;
	let b_htlc_key = &tx_keys.countersignatory_htlc_key;
	let delayed_payment_key = &tx_keys.broadcaster_delayed_payment_key;
	let per_commitment_point = &tx_keys.per_commitment_point;

	let mut nondust_htlcs = commitment_tx.nondust_htlcs().iter()
		.zip(commitment_tx.counterparty_htlc_sigs.iter());
	let mut sources = htlc_data.nondust_htlc_sources.iter();

	// Use an iterator to write `htlc_outputs` to avoid allocations.
	let nondust_htlcs = core::iter::from_fn(move || {
		let (htlc, counterparty_htlc_sig) = if let Some(nondust_htlc) = nondust_htlcs.next() {
			nondust_htlc
		} else {
			assert!(sources.next().is_none());
			return None;
		};

		let mut source = None;
		if htlc.offered {
			source = sources.next();
			if source.is_none() {
				panic!("Every offered non-dust HTLC should have a corresponding source");
			}
		}
		Some((htlc, Some(counterparty_htlc_sig), source))
	});

	// Dust HTLCs go last.
	let dust_htlcs = htlc_data.dust_htlcs.iter()
		.map(|(htlc, source)| (htlc, None::<&Signature>, source.as_ref()));
	let htlc_outputs = crate::util::ser::IterableOwned(nondust_htlcs.chain(dust_htlcs));

	write_tlv_fields!(writer, {
		(0, txid, required),
		(1, to_self_value_sat, required),
		(2, revocation_key, required),
		(4, a_htlc_key, required),
		(6, b_htlc_key, required),
		(8, delayed_payment_key, required),
		(10, per_commitment_point, required),
		(12, feerate_per_kw, required),
		(14, htlc_outputs, required),
	});

	Ok(())
}

/// We use this to track static counterparty commitment transaction data and to generate any
/// justice or 2nd-stage preimage/timeout transactions.
#[derive(Clone, PartialEq, Eq)]
struct CounterpartyCommitmentParameters {
	counterparty_delayed_payment_base_key: DelayedPaymentBasepoint,
	counterparty_htlc_base_key: HtlcBasepoint,
	on_counterparty_tx_csv: u16,
}

impl Writeable for CounterpartyCommitmentParameters {
	fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
		w.write_all(&0u64.to_be_bytes())?;
		write_tlv_fields!(w, {
			(0, self.counterparty_delayed_payment_base_key, required),
			(2, self.counterparty_htlc_base_key, required),
			(4, self.on_counterparty_tx_csv, required),
		});
		Ok(())
	}
}
impl Readable for CounterpartyCommitmentParameters {
	#[rustfmt::skip]
	fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
		let counterparty_commitment_transaction = {
			// Versions prior to 0.0.100 had some per-HTLC state stored here, which is no longer
			// used. Read it for compatibility.
			let per_htlc_len: u64 = Readable::read(r)?;
			for _ in 0..per_htlc_len {
				let _txid: Txid = Readable::read(r)?;
				let htlcs_count: u64 = Readable::read(r)?;
				for _ in 0..htlcs_count {
					let _htlc: HTLCOutputInCommitment = Readable::read(r)?;
				}
			}

			let mut counterparty_delayed_payment_base_key = RequiredWrapper(None);
			let mut counterparty_htlc_base_key = RequiredWrapper(None);
			let mut on_counterparty_tx_csv: u16 = 0;
			read_tlv_fields!(r, {
				(0, counterparty_delayed_payment_base_key, required),
				(2, counterparty_htlc_base_key, required),
				(4, on_counterparty_tx_csv, required),
			});
			CounterpartyCommitmentParameters {
				counterparty_delayed_payment_base_key: counterparty_delayed_payment_base_key.0.unwrap(),
				counterparty_htlc_base_key: counterparty_htlc_base_key.0.unwrap(),
				on_counterparty_tx_csv,
			}
		};
		Ok(counterparty_commitment_transaction)
	}
}

/// An entry for an [`OnchainEvent`], stating the block height and hash when the event was
/// observed, as well as the transaction causing it.
///
/// Used to determine when the on-chain event can be considered safe from a chain reorganization.
#[derive(Clone, PartialEq, Eq)]
struct OnchainEventEntry {
	txid: Txid,
	height: u32,
	block_hash: Option<BlockHash>, // Added as optional, will be filled in for any entry generated on 0.0.113 or after
	event: OnchainEvent,
	transaction: Option<Transaction>, // Added as optional, but always filled in, in LDK 0.0.110
}

impl OnchainEventEntry {
	#[rustfmt::skip]
	fn confirmation_threshold(&self) -> u32 {
		let mut conf_threshold = self.height + ANTI_REORG_DELAY - 1;
		match self.event {
			OnchainEvent::MaturingOutput {
				descriptor: SpendableOutputDescriptor::DelayedPaymentOutput(ref descriptor)
			} => {
				// A CSV'd transaction is confirmable in block (input height) + CSV delay, which means
				// it's broadcastable when we see the previous block.
				conf_threshold = cmp::max(conf_threshold, self.height + descriptor.to_self_delay as u32 - 1);
			},
			OnchainEvent::FundingSpendConfirmation { on_local_output_csv: Some(csv), .. } |
			OnchainEvent::HTLCSpendConfirmation { on_to_local_output_csv: Some(csv), .. } => {
				// A CSV'd transaction is confirmable in block (input height) + CSV delay, which means
				// it's broadcastable when we see the previous block.
				conf_threshold = cmp::max(conf_threshold, self.height + csv as u32 - 1);
			},
			_ => {},
		}
		conf_threshold
	}

	fn has_reached_confirmation_threshold(&self, best_block: &BestBlock) -> bool {
		best_block.height >= self.confirmation_threshold()
	}
}

/// The (output index, sats value) for the counterparty's output in a commitment transaction.
///
/// This was added as an `Option` in 0.0.110.
type CommitmentTxCounterpartyOutputInfo = Option<(u32, Amount)>;

/// Upon discovering of some classes of onchain tx by ChannelMonitor, we may have to take actions on it
/// once they mature to enough confirmations (ANTI_REORG_DELAY)
#[derive(Clone, PartialEq, Eq)]
enum OnchainEvent {
	/// An outbound HTLC failing after a transaction is confirmed. Used
	///  * when an outbound HTLC output is spent by us after the HTLC timed out
	///  * an outbound HTLC which was not present in the commitment transaction which appeared
	///    on-chain (either because it was not fully committed to or it was dust).
	/// Note that this is *not* used for preimage claims, as those are passed upstream immediately,
	/// appearing only as an `HTLCSpendConfirmation`, below.
	HTLCUpdate {
		source: HTLCSource,
		payment_hash: PaymentHash,
		htlc_value_satoshis: Option<u64>,
		/// None in the second case, above, ie when there is no relevant output in the commitment
		/// transaction which appeared on chain.
		commitment_tx_output_idx: Option<u32>,
	},
	/// An output waiting on [`ANTI_REORG_DELAY`] confirmations before we hand the user the
	/// [`SpendableOutputDescriptor`].
	MaturingOutput { descriptor: SpendableOutputDescriptor },
	/// A spend of the funding output, either a commitment transaction or a cooperative closing
	/// transaction.
	FundingSpendConfirmation {
		/// The CSV delay for the output of the funding spend transaction (implying it is a local
		/// commitment transaction, and this is the delay on the to_self output).
		on_local_output_csv: Option<u16>,
		/// If the funding spend transaction was a known remote commitment transaction, we track
		/// the output index and amount of the counterparty's `to_self` output here.
		///
		/// This allows us to generate a [`Balance::CounterpartyRevokedOutputClaimable`] for the
		/// counterparty output.
		commitment_tx_to_counterparty_output: CommitmentTxCounterpartyOutputInfo,
	},
	/// A spend of a commitment transaction HTLC output, set in the cases where *no* `HTLCUpdate`
	/// is constructed. This is used when
	///  * an outbound HTLC is claimed by our counterparty with a preimage, causing us to
	///    immediately claim the HTLC on the inbound edge and track the resolution here,
	///  * an inbound HTLC is claimed by our counterparty (with a timeout),
	///  * an inbound HTLC is claimed by us (with a preimage).
	///  * a revoked-state HTLC transaction was broadcasted, which was claimed by the revocation
	///    signature.
	///  * a revoked-state HTLC transaction was broadcasted, which was claimed by an
	///    HTLC-Success/HTLC-Failure transaction (and is still claimable with a revocation
	///    signature).
	HTLCSpendConfirmation {
		commitment_tx_output_idx: u32,
		/// If the claim was made by either party with a preimage, this is filled in
		preimage: Option<PaymentPreimage>,
		/// If the claim was made by us on an inbound HTLC against a local commitment transaction,
		/// we set this to the output CSV value which we will have to wait until to spend the
		/// output (and generate a SpendableOutput event).
		on_to_local_output_csv: Option<u16>,
	},
	/// An alternative funding transaction (due to a splice/RBF) has confirmed but can no longer be
	/// locked now as the monitor is no longer allowing updates. Note that we wait to promote the
	/// corresponding `FundingScope` until we see a
	/// [`ChannelMonitorUpdateStep::RenegotiatedFundingLocked`], but this event is only applicable
	/// once [`ChannelMonitor::no_further_updates_allowed`] returns true. We promote the
	/// `FundingScope` once the funding transaction is irrevocably confirmed.
	AlternativeFundingConfirmation {},
}

impl Writeable for OnchainEventEntry {
	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
		write_tlv_fields!(writer, {
			(0, self.txid, required),
			(1, self.transaction, option),
			(2, self.height, required),
			(3, self.block_hash, option),
			(4, self.event, required),
		});
		Ok(())
	}
}

impl MaybeReadable for OnchainEventEntry {
	#[rustfmt::skip]
	fn read<R: io::Read>(reader: &mut R) -> Result<Option<Self>, DecodeError> {
		let mut txid = Txid::all_zeros();
		let mut transaction = None;
		let mut block_hash = None;
		let mut height = 0;
		let mut event = UpgradableRequired(None);
		read_tlv_fields!(reader, {
			(0, txid, required),
			(1, transaction, option),
			(2, height, required),
			(3, block_hash, option),
			(4, event, upgradable_required),
		});
		Ok(Some(Self { txid, transaction, height, block_hash, event: _init_tlv_based_struct_field!(event, upgradable_required) }))
	}
}

impl_writeable_tlv_based_enum_upgradable!(OnchainEvent,
	(0, HTLCUpdate) => {
		(0, source, required),
		(1, htlc_value_satoshis, option),
		(2, payment_hash, required),
		(3, commitment_tx_output_idx, option),
	},
	(1, MaturingOutput) => {
		(0, descriptor, required),
	},
	(2, AlternativeFundingConfirmation) => {},
	(3, FundingSpendConfirmation) => {
		(0, on_local_output_csv, option),
		(1, commitment_tx_to_counterparty_output, option),
	},
	(5, HTLCSpendConfirmation) => {
		(0, commitment_tx_output_idx, required),
		(2, preimage, option),
		(4, on_to_local_output_csv, option),
	},
);

#[derive(Clone, Debug, PartialEq, Eq)]
pub(crate) enum ChannelMonitorUpdateStep {
	LatestHolderCommitmentTXInfo {
		commitment_tx: HolderCommitmentTransaction,
		/// Note that LDK after 0.0.115 supports this only containing dust HTLCs (implying the
		/// `Signature` field is never filled in). At that point, non-dust HTLCs are implied by the
		/// HTLC fields in `commitment_tx` and the sources passed via `nondust_htlc_sources`.
		/// Starting with 0.2, the non-dust HTLC sources will always be provided separately, and
		/// `htlc_outputs` will only include dust HTLCs. We still have to track the
		/// `Option<Signature>` for backwards compatibility.
		htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Signature>, Option<HTLCSource>)>,
		claimed_htlcs: Vec<(SentHTLCId, PaymentPreimage)>,
		nondust_htlc_sources: Vec<HTLCSource>,
	},
	LatestHolderCommitment {
		commitment_txs: Vec<HolderCommitmentTransaction>,
		htlc_data: CommitmentHTLCData,
		claimed_htlcs: Vec<(SentHTLCId, PaymentPreimage)>,
	},
	LatestCounterpartyCommitmentTXInfo {
		commitment_txid: Txid,
		htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Box<HTLCSource>>)>,
		commitment_number: u64,
		their_per_commitment_point: PublicKey,
		feerate_per_kw: Option<u32>,
		to_broadcaster_value_sat: Option<u64>,
		to_countersignatory_value_sat: Option<u64>,
	},
	LatestCounterpartyCommitment {
		commitment_txs: Vec<CommitmentTransaction>,
		htlc_data: CommitmentHTLCData,
	},
	PaymentPreimage {
		payment_preimage: PaymentPreimage,
		/// If this preimage was from an inbound payment claim, information about the claim should
		/// be included here to enable claim replay on startup.
		payment_info: Option<PaymentClaimDetails>,
	},
	CommitmentSecret {
		idx: u64,
		secret: [u8; 32],
	},
	/// Used to indicate that the no future updates will occur, and likely that the latest holder
	/// commitment transaction(s) should be broadcast, as the channel has been force-closed.
	ChannelForceClosed {
		/// If set to false, we shouldn't broadcast the latest holder commitment transaction as we
		/// think we've fallen behind!
		should_broadcast: bool,
	},
	ShutdownScript {
		scriptpubkey: ScriptBuf,
	},
	RenegotiatedFunding {
		channel_parameters: ChannelTransactionParameters,
		holder_commitment_tx: HolderCommitmentTransaction,
		counterparty_commitment_tx: CommitmentTransaction,
	},
	RenegotiatedFundingLocked {
		funding_txid: Txid,
	},
	/// When a payment is finally resolved by the user handling an [`Event::PaymentSent`] or
	/// [`Event::PaymentFailed`] event, the `ChannelManager` no longer needs to hear about it on
	/// startup (which would cause it to re-hydrate the payment information even though the user
	/// already learned about the payment's result).
	///
	/// This will remove the HTLC from [`ChannelMonitor::get_all_current_outbound_htlcs`] and
	/// [`ChannelMonitor::get_onchain_failed_outbound_htlcs`].
	///
	/// Note that this is only generated for closed channels as this is implicit in the
	/// [`Self::CommitmentSecret`] update which clears the payment information from all un-revoked
	/// counterparty commitment transactions.
	ReleasePaymentComplete {
		htlc: SentHTLCId,
	},
}

impl ChannelMonitorUpdateStep {
	#[rustfmt::skip]
	fn variant_name(&self) -> &'static str {
		match self {
			ChannelMonitorUpdateStep::LatestHolderCommitmentTXInfo { .. } => "LatestHolderCommitmentTXInfo",
			ChannelMonitorUpdateStep::LatestHolderCommitment { .. } => "LatestHolderCommitment",
			ChannelMonitorUpdateStep::LatestCounterpartyCommitmentTXInfo { .. } => "LatestCounterpartyCommitmentTXInfo",
			ChannelMonitorUpdateStep::LatestCounterpartyCommitment { .. } => "LatestCounterpartyCommitment",
			ChannelMonitorUpdateStep::PaymentPreimage { .. } => "PaymentPreimage",
			ChannelMonitorUpdateStep::CommitmentSecret { .. } => "CommitmentSecret",
			ChannelMonitorUpdateStep::ChannelForceClosed { .. } => "ChannelForceClosed",
			ChannelMonitorUpdateStep::ShutdownScript { .. } => "ShutdownScript",
			ChannelMonitorUpdateStep::RenegotiatedFunding { .. } => "RenegotiatedFunding",
			ChannelMonitorUpdateStep::RenegotiatedFundingLocked { .. } => "RenegotiatedFundingLocked",
			ChannelMonitorUpdateStep::ReleasePaymentComplete { .. } => "ReleasePaymentComplete",
		}
	}
}

impl_writeable_tlv_based_enum_upgradable!(ChannelMonitorUpdateStep,
	(0, LatestHolderCommitmentTXInfo) => {
		(0, commitment_tx, required),
		(1, claimed_htlcs, optional_vec),
		(2, htlc_outputs, required_vec),
		(4, nondust_htlc_sources, optional_vec),
	},
	(1, LatestCounterpartyCommitmentTXInfo) => {
		(0, commitment_txid, required),
		(1, feerate_per_kw, option),
		(2, commitment_number, required),
		(3, to_broadcaster_value_sat, option),
		(4, their_per_commitment_point, required),
		(5, to_countersignatory_value_sat, option),
		(6, htlc_outputs, required_vec),
	},
	(2, PaymentPreimage) => {
		(0, payment_preimage, required),
		(1, payment_info, option),
	},
	(3, CommitmentSecret) => {
		(0, idx, required),
		(2, secret, required),
	},
	(4, ChannelForceClosed) => {
		(0, should_broadcast, required),
	},
	(5, ShutdownScript) => {
		(0, scriptpubkey, required),
	},
	(6, LatestCounterpartyCommitment) => {
		(1, commitment_txs, required_vec),
		(3, htlc_data, required),
	},
	(7, ReleasePaymentComplete) => {
		(1, htlc, required),
	},
	(8, LatestHolderCommitment) => {
		(1, commitment_txs, required_vec),
		(3, htlc_data, required),
		(5, claimed_htlcs, required_vec),
	},
	(10, RenegotiatedFunding) => {
		(1, channel_parameters, (required: ReadableArgs, None)),
		(3, holder_commitment_tx, required),
		(5, counterparty_commitment_tx, required),
	},
	(12, RenegotiatedFundingLocked) => {
		(1, funding_txid, required),
	},
);

/// Indicates whether the balance is derived from a cooperative close, a force-close
/// (for holder or counterparty), or whether it is for an HTLC.
#[derive(Clone, Debug, PartialEq, Eq)]
#[cfg_attr(test, derive(PartialOrd, Ord))]
pub enum BalanceSource {
	/// The channel was force closed by the holder.
	HolderForceClosed,
	/// The channel was force closed by the counterparty.
	CounterpartyForceClosed,
	/// The channel was cooperatively closed.
	CoopClose,
	/// This balance is the result of an HTLC.
	Htlc,
}

/// The claimable balance of a holder commitment transaction that has yet to be broadcast.
#[derive(Clone, Debug, PartialEq, Eq)]
#[cfg_attr(test, derive(PartialOrd, Ord))]
pub struct HolderCommitmentTransactionBalance {
	/// The amount available to claim, in satoshis, excluding the on-chain fees which will be
	/// required to do so.
	pub amount_satoshis: u64,
	/// The transaction fee we pay for the closing commitment transaction. This amount is not
	/// included in the [`HolderCommitmentTransactionBalance::amount_satoshis`] value.
	/// This amount includes the sum of dust HTLCs on the commitment transaction, any elided anchors,
	/// as well as the sum of msat amounts rounded down from non-dust HTLCs.
	///
	/// Note that if this channel is inbound (and thus our counterparty pays the commitment
	/// transaction fee) this value will be zero. For [`ChannelMonitor`]s created prior to LDK
	/// 0.0.124, the channel is always treated as outbound (and thus this value is never zero).
	pub transaction_fee_satoshis: u64,
}

/// Details about the balance(s) available for spending once the channel appears on chain.
///
/// See [`ChannelMonitor::get_claimable_balances`] for more details on when these will or will not
/// be provided.
#[derive(Clone, Debug, PartialEq, Eq)]
#[cfg_attr(test, derive(PartialOrd, Ord))]
pub enum Balance {
	/// The channel is not yet closed (or the commitment or closing transaction has not yet
	/// appeared in a block).
	ClaimableOnChannelClose {
		/// A list of balance candidates based on the latest set of valid holder commitment
		/// transactions that can hit the chain. Typically, a channel only has one valid holder
		/// commitment transaction that spends the current funding output. As soon as a channel is
		/// spliced, an alternative holder commitment transaction exists spending the new funding
		/// output. More alternative holder commitment transactions can exist as the splice remains
		/// pending and RBF attempts are made.
		///
		/// The candidates are sorted by the order in which the holder commitment transactions were
		/// negotiated. When only one candidate exists, the channel does not have a splice pending.
		/// When multiple candidates exist, the last one reflects the balance of the
		/// latest splice/RBF attempt, while the first reflects the balance prior to the splice
		/// occurring.
		///
		/// Entries remain in this vec until the pending splice has reached [`ANTI_REORG_DELAY`]
		/// confirmations, at which point any conflicts will be removed. Once a splice confirms
		/// [`Self::ClaimableOnChannelClose::confirmed_balance_candidate_index`] will point to the
		/// confirmed entry, even if it has fewer than [`ANTI_REORG_DELAY`] confirmations.
		balance_candidates: Vec<HolderCommitmentTransactionBalance>,
		/// The index within [`Balance::ClaimableOnChannelClose::balance_candidates`] for the
		/// balance according to the current onchain state of the channel. This can be helpful when
		/// wanting to determine the claimable amount when the holder commitment transaction for the
		/// current funding transaction is broadcast and/or confirms.
		confirmed_balance_candidate_index: usize,
		/// The amount of millisatoshis which has been burned to fees from HTLCs which are outbound
		/// from us and are related to a payment which was sent by us. This is the sum of the
		/// millisatoshis part of all HTLCs which are otherwise represented by
		/// [`Balance::MaybeTimeoutClaimableHTLC`] with their
		/// [`Balance::MaybeTimeoutClaimableHTLC::outbound_payment`] flag set, as well as any dust
		/// HTLCs which would otherwise be represented the same.
		///
		/// This amount (rounded up to a whole satoshi value) will not be included in `amount_satoshis`.
		outbound_payment_htlc_rounded_msat: u64,
		/// The amount of millisatoshis which has been burned to fees from HTLCs which are outbound
		/// from us and are related to a forwarded HTLC. This is the sum of the millisatoshis part
		/// of all HTLCs which are otherwise represented by [`Balance::MaybeTimeoutClaimableHTLC`]
		/// with their [`Balance::MaybeTimeoutClaimableHTLC::outbound_payment`] flag *not* set, as
		/// well as any dust HTLCs which would otherwise be represented the same.
		///
		/// This amount (rounded up to a whole satoshi value) will not be included in `amount_satoshis`.
		outbound_forwarded_htlc_rounded_msat: u64,
		/// The amount of millisatoshis which has been burned to fees from HTLCs which are inbound
		/// to us and for which we know the preimage. This is the sum of the millisatoshis part of
		/// all HTLCs which would be represented by [`Balance::ContentiousClaimable`] on channel
		/// close, but whose current value is included in
		/// [`HolderCommitmentTransactionBalance::amount_satoshis`], as well as any dust HTLCs which
		/// would otherwise be represented the same.
		///
		/// This amount (rounded up to a whole satoshi value) will not be included in the counterparty's
		/// `amount_satoshis`.
		inbound_claiming_htlc_rounded_msat: u64,
		/// The amount of millisatoshis which has been burned to fees from HTLCs which are inbound
		/// to us and for which we do not know the preimage. This is the sum of the millisatoshis
		/// part of all HTLCs which would be represented by [`Balance::MaybePreimageClaimableHTLC`]
		/// on channel close, as well as any dust HTLCs which would otherwise be represented the
		/// same.
		///
		/// This amount (rounded up to a whole satoshi value) will not be included in the counterparty's
		/// `amount_satoshis`.
		inbound_htlc_rounded_msat: u64,
	},
	/// The channel has been closed, and the given balance is ours but awaiting confirmations until
	/// we consider it spendable.
	ClaimableAwaitingConfirmations {
		/// The amount available to claim, in satoshis, possibly excluding the on-chain fees which
		/// were spent in broadcasting the transaction.
		amount_satoshis: u64,
		/// The height at which an [`Event::SpendableOutputs`] event will be generated for this
		/// amount.
		confirmation_height: u32,
		/// Whether this balance is a result of cooperative close, a force-close, or an HTLC.
		source: BalanceSource,
	},
	/// The channel has been closed, and the given balance should be ours but awaiting spending
	/// transaction confirmation. If the spending transaction does not confirm in time, it is
	/// possible our counterparty can take the funds by broadcasting an HTLC timeout on-chain.
	///
	/// Once the spending transaction confirms, before it has reached enough confirmations to be
	/// considered safe from chain reorganizations, the balance will instead be provided via
	/// [`Balance::ClaimableAwaitingConfirmations`].
	ContentiousClaimable {
		/// The amount available to claim, in satoshis, excluding the on-chain fees which will be
		/// required to do so.
		amount_satoshis: u64,
		/// The height at which the counterparty may be able to claim the balance if we have not
		/// done so.
		timeout_height: u32,
		/// The payment hash that locks this HTLC.
		payment_hash: PaymentHash,
		/// The preimage that can be used to claim this HTLC.
		payment_preimage: PaymentPreimage,
	},
	/// HTLCs which we sent to our counterparty which are claimable after a timeout (less on-chain
	/// fees) if the counterparty does not know the preimage for the HTLCs. These are somewhat
	/// likely to be claimed by our counterparty before we do.
	MaybeTimeoutClaimableHTLC {
		/// The amount potentially available to claim, in satoshis, excluding the on-chain fees
		/// which will be required to do so.
		amount_satoshis: u64,
		/// The height at which we will be able to claim the balance if our counterparty has not
		/// done so.
		claimable_height: u32,
		/// The payment hash whose preimage our counterparty needs to claim this HTLC.
		payment_hash: PaymentHash,
		/// Whether this HTLC represents a payment which was sent outbound from us. Otherwise it
		/// represents an HTLC which was forwarded (and should, thus, have a corresponding inbound
		/// edge on another channel).
		outbound_payment: bool,
	},
	/// HTLCs which we received from our counterparty which are claimable with a preimage which we
	/// do not currently have. This will only be claimable if we receive the preimage from the node
	/// to which we forwarded this HTLC before the timeout.
	MaybePreimageClaimableHTLC {
		/// The amount potentially available to claim, in satoshis, excluding the on-chain fees
		/// which will be required to do so.
		amount_satoshis: u64,
		/// The height at which our counterparty will be able to claim the balance if we have not
		/// yet received the preimage and claimed it ourselves.
		expiry_height: u32,
		/// The payment hash whose preimage we need to claim this HTLC.
		payment_hash: PaymentHash,
	},
	/// The channel has been closed, and our counterparty broadcasted a revoked commitment
	/// transaction.
	///
	/// Thus, we're able to claim all outputs in the commitment transaction, one of which has the
	/// following amount.
	CounterpartyRevokedOutputClaimable {
		/// The amount, in satoshis, of the output which we can claim.
		///
		/// Note that for outputs from HTLC balances this may be excluding some on-chain fees that
		/// were already spent.
		amount_satoshis: u64,
	},
}

impl Balance {
	/// The amount claimable, in satoshis.
	///
	/// When the channel has yet to close, this returns the balance we expect to claim from the
	/// channel. This may change throughout the lifetime of the channel due to payments, but also
	/// due to splicing. If there's a pending splice, this will return the balance we expect to have
	/// assuming the latest negotiated splice confirms. However, if one of the negotiated splice
	/// transactions has already confirmed but is not yet locked, this reports the corresponding
	/// balance for said splice transaction instead.
	///
	/// For outbound payments, this excludes the balance from the possible HTLC timeout.
	///
	/// For forwarded payments, this includes the balance from the possible HTLC timeout as
	/// (to be conservative) that balance does not include routing fees we'd earn if we'd claim
	/// the balance from a preimage in a successful forward.
	///
	/// For more information on these balances see [`Balance::MaybeTimeoutClaimableHTLC`] and
	/// [`Balance::MaybePreimageClaimableHTLC`].
	///
	/// On-chain fees required to claim the balance are not included in this amount.
	#[rustfmt::skip]
	pub fn claimable_amount_satoshis(&self) -> u64 {
		match self {
			Balance::ClaimableOnChannelClose {
				balance_candidates, confirmed_balance_candidate_index, ..
			} => {
				if *confirmed_balance_candidate_index != 0 {
					balance_candidates[*confirmed_balance_candidate_index].amount_satoshis
				} else {
					balance_candidates.last().map(|balance| balance.amount_satoshis).unwrap_or(0)
				}
			},
			Balance::ClaimableAwaitingConfirmations { amount_satoshis, .. }|
			Balance::ContentiousClaimable { amount_satoshis, .. }|
			Balance::CounterpartyRevokedOutputClaimable { amount_satoshis, .. }
				=> *amount_satoshis,
			Balance::MaybeTimeoutClaimableHTLC { amount_satoshis, outbound_payment, .. }
				=> if *outbound_payment { 0 } else { *amount_satoshis },
			Balance::MaybePreimageClaimableHTLC { .. } => 0,
		}
	}
}

/// An HTLC which has been irrevocably resolved on-chain, and has reached ANTI_REORG_DELAY.
#[derive(Clone, PartialEq, Eq)]
struct IrrevocablyResolvedHTLC {
	commitment_tx_output_idx: Option<u32>,
	/// The txid of the transaction which resolved the HTLC, this may be a commitment (if the HTLC
	/// was not present in the confirmed commitment transaction), HTLC-Success, or HTLC-Timeout
	/// transaction.
	resolving_txid: Option<Txid>, // Added as optional, but always filled in, in 0.0.110
	resolving_tx: Option<Transaction>,
	/// Only set if the HTLC claim was ours using a payment preimage
	payment_preimage: Option<PaymentPreimage>,
}

/// In LDK versions prior to 0.0.111 commitment_tx_output_idx was not Option-al and
/// IrrevocablyResolvedHTLC objects only existed for non-dust HTLCs. This was a bug, but to maintain
/// backwards compatibility we must ensure we always write out a commitment_tx_output_idx field,
/// using [`u32::MAX`] as a sentinal to indicate the HTLC was dust.
impl Writeable for IrrevocablyResolvedHTLC {
	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
		let mapped_commitment_tx_output_idx = self.commitment_tx_output_idx.unwrap_or(u32::MAX);
		write_tlv_fields!(writer, {
			(0, mapped_commitment_tx_output_idx, required),
			(1, self.resolving_txid, option),
			(2, self.payment_preimage, option),
			(3, self.resolving_tx, option),
		});
		Ok(())
	}
}

impl Readable for IrrevocablyResolvedHTLC {
	#[rustfmt::skip]
	fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
		let mut mapped_commitment_tx_output_idx = 0;
		let mut resolving_txid = None;
		let mut payment_preimage = None;
		let mut resolving_tx = None;
		read_tlv_fields!(reader, {
			(0, mapped_commitment_tx_output_idx, required),
			(1, resolving_txid, option),
			(2, payment_preimage, option),
			(3, resolving_tx, option),
		});
		Ok(Self {
			commitment_tx_output_idx: if mapped_commitment_tx_output_idx == u32::MAX { None } else { Some(mapped_commitment_tx_output_idx) },
			resolving_txid,
			payment_preimage,
			resolving_tx,
		})
	}
}

/// A ChannelMonitor handles chain events (blocks connected and disconnected) and generates
/// on-chain transactions to ensure no loss of funds occurs.
///
/// You MUST ensure that no ChannelMonitors for a given channel anywhere contain out-of-date
/// information and are actively monitoring the chain.
///
/// Like the [`ChannelManager`], deserialization is implemented for `(BlockHash, ChannelMonitor)`,
/// providing you with the last block hash which was connected before shutting down. You must begin
/// syncing the chain from that point, disconnecting and connecting blocks as required to get to
/// the best chain on startup. Note that all [`ChannelMonitor`]s passed to a [`ChainMonitor`] must
/// by synced as of the same block, so syncing must happen prior to [`ChainMonitor`]
/// initialization.
///
/// For those loading potentially-ancient [`ChannelMonitor`]s, deserialization is also implemented
/// for `Option<(BlockHash, ChannelMonitor)>`. LDK can no longer deserialize a [`ChannelMonitor`]
/// that was first created in LDK prior to 0.0.110 and last updated prior to LDK 0.0.119. In such
/// cases, the `Option<(..)>` deserialization option may return `Ok(None)` rather than failing to
/// deserialize, allowing you to differentiate between the two cases.
///
/// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
/// [`ChainMonitor`]: crate::chain::chainmonitor::ChainMonitor
pub struct ChannelMonitor<Signer: EcdsaChannelSigner> {
	pub(crate) inner: Mutex<ChannelMonitorImpl<Signer>>,
}

impl<Signer: EcdsaChannelSigner> Clone for ChannelMonitor<Signer>
where
	Signer: Clone,
{
	fn clone(&self) -> Self {
		let inner = self.inner.lock().unwrap().clone();
		ChannelMonitor::from_impl(inner)
	}
}

#[derive(Clone, Debug, PartialEq, Eq)]
pub(crate) struct CommitmentHTLCData {
	// These must be sorted in increasing output index order to match the expected order of the
	// HTLCs in the `CommitmentTransaction`.
	pub nondust_htlc_sources: Vec<HTLCSource>,
	pub dust_htlcs: Vec<(HTLCOutputInCommitment, Option<HTLCSource>)>,
}

impl CommitmentHTLCData {
	fn new() -> Self {
		Self { nondust_htlc_sources: Vec::new(), dust_htlcs: Vec::new() }
	}
}

impl_writeable_tlv_based!(CommitmentHTLCData, {
	(1, nondust_htlc_sources, required_vec),
	(3, dust_htlcs, required_vec),
});

impl TryFrom<HolderSignedTx> for CommitmentHTLCData {
	type Error = ();
	#[rustfmt::skip]
	fn try_from(value: HolderSignedTx) -> Result<Self, Self::Error> {
		// HolderSignedTx tracks all HTLCs included in the commitment (dust included). For
		// `HolderCommitment`, we'll need to extract the dust HTLCs and their sources, and non-dust
		// HTLC sources, separately. All offered, non-dust HTLCs must have a source available.
		let mut missing_nondust_source = false;
		let mut nondust_htlc_sources = Vec::with_capacity(value.htlc_outputs.len());
		let dust_htlcs = value.htlc_outputs.into_iter().filter_map(|(htlc, _, source)| {
			// Filter our non-dust HTLCs, while at the same time pushing their sources into
			// `nondust_htlc_sources`.
			if htlc.transaction_output_index.is_none() {
				return Some((htlc, source))
			}
			if htlc.offered {
				if let Some(source) = source {
					nondust_htlc_sources.push(source);
				} else {
					missing_nondust_source = true;
				}
			}
			None
		}).collect();
		if missing_nondust_source {
			return Err(());
		}

		Ok(Self {
			nondust_htlc_sources,
			dust_htlcs,
		})
	}
}

#[derive(Clone, PartialEq)]
struct FundingScope {
	channel_parameters: ChannelTransactionParameters,

	current_counterparty_commitment_txid: Option<Txid>,
	prev_counterparty_commitment_txid: Option<Txid>,

	/// The set of outpoints in each counterparty commitment transaction. We always need at least
	/// the payment hash from `HTLCOutputInCommitment` to claim even a revoked commitment
	/// transaction broadcast as we need to be able to construct the witness script in all cases.
	//
	// TODO(splicing): We shouldn't have to track these duplicatively per `FundingScope`. Ideally,
	// we have a global map to track the HTLCs, along with their source, as they should be
	// consistent across all commitments. Unfortunately, doing so requires that our HTLCs are not
	// tied to their respective commitment transaction via `transaction_output_index`, as those may
	// not be consistent across all commitments.
	counterparty_claimable_outpoints:
		HashMap<Txid, Vec<(HTLCOutputInCommitment, Option<Box<HTLCSource>>)>>,

	// We store two holder commitment transactions to avoid any race conditions where we may update
	// some monitors (potentially on watchtowers) but then fail to update others, resulting in the
	// various monitors for one channel being out of sync, and us broadcasting a holder
	// transaction for which we have deleted claim information on some watchtowers.
	current_holder_commitment_tx: HolderCommitmentTransaction,
	prev_holder_commitment_tx: Option<HolderCommitmentTransaction>,
}

impl FundingScope {
	fn funding_outpoint(&self) -> OutPoint {
		let funding_outpoint = self.channel_parameters.funding_outpoint.as_ref();
		*funding_outpoint.expect("Funding outpoint must be set for active monitor")
	}

	fn funding_txid(&self) -> Txid {
		self.funding_outpoint().txid
	}

	fn is_splice(&self) -> bool {
		self.channel_parameters.splice_parent_funding_txid.is_some()
	}

	fn channel_type_features(&self) -> &ChannelTypeFeatures {
		&self.channel_parameters.channel_type_features
	}
}

impl_writeable_tlv_based!(FundingScope, {
	(1, channel_parameters, (required: ReadableArgs, None)),
	(3, current_counterparty_commitment_txid, required),
	(5, prev_counterparty_commitment_txid, option),
	(7, current_holder_commitment_tx, required),
	(9, prev_holder_commitment_tx, option),
	(11, counterparty_claimable_outpoints, required),
});

#[derive(Clone, PartialEq)]
pub(crate) struct ChannelMonitorImpl<Signer: EcdsaChannelSigner> {
	funding: FundingScope,
	pending_funding: Vec<FundingScope>,

	/// True if this channel was configured for manual funding broadcasts. Monitors written by
	/// versions prior to LDK 0.2 load with `false` until a new update persists it.
	is_manual_broadcast: bool,
	/// True once we've observed either funding transaction on-chain. Older monitors prior to LDK 0.2
	/// assume this is `true` when absent during upgrade so holder broadcasts aren't gated unexpectedly.
	/// In manual-broadcast channels we also use this to trigger deferred holder
	/// broadcasts once the funding transaction finally appears on-chain.
	///
	/// Note: This tracks whether the funding transaction was ever broadcast, not whether it is
	/// currently confirmed. It is never reset, even if the funding transaction is unconfirmed due
	/// to a reorg.
	funding_seen_onchain: bool,

	latest_update_id: u64,
	commitment_transaction_number_obscure_factor: u64,

	destination_script: ScriptBuf,
	broadcasted_holder_revokable_script: Option<(ScriptBuf, PublicKey, RevocationKey)>,
	counterparty_payment_script: ScriptBuf,
	shutdown_script: Option<ScriptBuf>,

	channel_keys_id: [u8; 32],
	holder_revocation_basepoint: RevocationBasepoint,
	channel_id: ChannelId,
	first_negotiated_funding_txo: OutPoint,

	counterparty_commitment_params: CounterpartyCommitmentParameters,

	// first is the idx of the first of the two per-commitment points
	their_cur_per_commitment_points: Option<(u64, PublicKey, Option<PublicKey>)>,

	on_holder_tx_csv: u16,

	commitment_secrets: CounterpartyCommitmentSecrets,
	/// We cannot identify HTLC-Success or HTLC-Timeout transactions by themselves on the chain.
	/// Nor can we figure out their commitment numbers without the commitment transaction they are
	/// spending. Thus, in order to claim them via revocation key, we track all the counterparty
	/// commitment transactions which we find on-chain, mapping them to the commitment number which
	/// can be used to derive the revocation key and claim the transactions.
	counterparty_commitment_txn_on_chain: HashMap<Txid, u64>,
	/// Cache used to make pruning of payment_preimages faster.
	/// Maps payment_hash values to commitment numbers for counterparty transactions for non-revoked
	/// counterparty transactions (ie should remain pretty small).
	/// Serialized to disk but should generally not be sent to Watchtowers.
	counterparty_hash_commitment_number: HashMap<PaymentHash, u64>,

	counterparty_fulfilled_htlcs: HashMap<SentHTLCId, PaymentPreimage>,

	// Used just for ChannelManager to make sure it has the latest channel data during
	// deserialization
	current_counterparty_commitment_number: u64,
	// Used just for ChannelManager to make sure it has the latest channel data during
	// deserialization
	current_holder_commitment_number: u64,

	/// The set of payment hashes from inbound payments for which we know the preimage. Payment
	/// preimages that are not included in any unrevoked local commitment transaction or unrevoked
	/// remote commitment transactions are automatically removed when commitment transactions are
	/// revoked. Note that this happens one revocation after it theoretically could, leaving
	/// preimages present here for the previous state even when the channel is "at rest". This is a
	/// good safety buffer, but also is important as it ensures we retain payment preimages for the
	/// previous local commitment transaction, which may have been broadcast already when we see
	/// the revocation (in setups with redundant monitors).
	///
	/// We also store [`PaymentClaimDetails`] here, tracking the payment information(s) for this
	/// preimage for inbound payments. This allows us to rebuild the inbound payment information on
	/// startup even if we lost our `ChannelManager`.
	payment_preimages: HashMap<PaymentHash, (PaymentPreimage, Vec<PaymentClaimDetails>)>,

	// Note that `MonitorEvent`s MUST NOT be generated during update processing, only generated
	// during chain data processing. This prevents a race in `ChainMonitor::update_channel` (and
	// presumably user implementations thereof as well) where we update the in-memory channel
	// object, then before the persistence finishes (as it's all under a read-lock), we return
	// pending events to the user or to the relevant `ChannelManager`. Then, on reload, we'll have
	// the pre-event state here, but have processed the event in the `ChannelManager`.
	// Note that because the `event_lock` in `ChainMonitor` is only taken in
	// block/transaction-connected events and *not* during block/transaction-disconnected events,
	// we further MUST NOT generate events during block/transaction-disconnection.
	pending_monitor_events: Vec<MonitorEvent>,

	pub(super) pending_events: Vec<Event>,
	pub(super) is_processing_pending_events: bool,

	// Used to track on-chain events (i.e., transactions part of channels confirmed on chain) on
	// which to take actions once they reach enough confirmations. Each entry includes the
	// transaction's id and the height when the transaction was confirmed on chain.
	onchain_events_awaiting_threshold_conf: Vec<OnchainEventEntry>,

	// If we get serialized out and re-read, we need to make sure that the chain monitoring
	// interface knows about the TXOs that we want to be notified of spends of. We could probably
	// be smart and derive them from the above storage fields, but its much simpler and more
	// Obviously Correct (tm) if we just keep track of them explicitly.
	outputs_to_watch: HashMap<Txid, Vec<(u32, ScriptBuf)>>,

	#[cfg(any(test, feature = "_test_utils"))]
	pub onchain_tx_handler: OnchainTxHandler<Signer>,
	#[cfg(not(any(test, feature = "_test_utils")))]
	onchain_tx_handler: OnchainTxHandler<Signer>,

	// This is set when the Channel[Manager] generated a ChannelMonitorUpdate which indicated the
	// channel has been force-closed. After this is set, no further holder commitment transaction
	// updates may occur, and we panic!() if one is provided.
	lockdown_from_offchain: bool,

	// Set once we've signed a holder commitment transaction and handed it over to our
	// OnchainTxHandler. After this is set, no future updates to our holder commitment transactions
	// may occur, and we fail any such monitor updates.
	//
	// In case of update rejection due to a locally already signed commitment transaction, we
	// nevertheless store update content to track in case of concurrent broadcast by another
	// remote monitor out-of-order with regards to the block view.
	holder_tx_signed: bool,

	// If a spend of the funding output is seen, we set this to true and reject any further
	// updates. This prevents any further changes in the offchain state no matter the order
	// of block connection between ChannelMonitors and the ChannelManager.
	funding_spend_seen: bool,

	/// True if the commitment transaction fee is paid by us.
	/// Added in 0.0.124.
	holder_pays_commitment_tx_fee: Option<bool>,

	/// Set to `Some` of the confirmed transaction spending the funding input of the channel after
	/// reaching `ANTI_REORG_DELAY` confirmations.
	funding_spend_confirmed: Option<Txid>,

	confirmed_commitment_tx_counterparty_output: CommitmentTxCounterpartyOutputInfo,
	/// The set of HTLCs which have been either claimed or failed on chain and have reached
	/// the requisite confirmations on the claim/fail transaction (either ANTI_REORG_DELAY or the
	/// spending CSV for revocable outputs).
	htlcs_resolved_on_chain: Vec<IrrevocablyResolvedHTLC>,

	/// When a payment is resolved through an on-chain transaction, we tell the `ChannelManager`
	/// about this via [`ChannelMonitor::get_onchain_failed_outbound_htlcs`] and
	/// [`ChannelMonitor::get_all_current_outbound_htlcs`] at startup. We'll keep repeating the
	/// same payments until they're eventually fully resolved by the user processing a
	/// `PaymentSent` or `PaymentFailed` event, at which point the `ChannelManager` will inform of
	/// this and we'll store the set of fully resolved payments here.
	htlcs_resolved_to_user: HashSet<SentHTLCId>,

	/// The set of `SpendableOutput` events which we have already passed upstream to be claimed.
	/// These are tracked explicitly to ensure that we don't generate the same events redundantly
	/// if users duplicatively confirm old transactions. Specifically for transactions claiming a
	/// revoked remote outpoint we otherwise have no tracking at all once they've reached
	/// [`ANTI_REORG_DELAY`], so we have to track them here.
	spendable_txids_confirmed: Vec<Txid>,

	// We simply modify best_block in Channel's block_connected so that serialization is
	// consistent but hopefully the users' copy handles block_connected in a consistent way.
	// (we do *not*, however, update them in update_monitor to ensure any local user copies keep
	// their best_block from its state and not based on updated copies that didn't run through
	// the full block_connected).
	best_block: BestBlock,

	/// The node_id of our counterparty
	counterparty_node_id: PublicKey,

	/// Initial counterparty commmitment data needed to recreate the commitment tx
	/// in the persistence pipeline for third-party watchtowers. This will only be present on
	/// monitors created after 0.0.117.
	///
	/// Ordering of tuple data: (their_per_commitment_point, feerate_per_kw, to_broadcaster_sats,
	/// to_countersignatory_sats)
	initial_counterparty_commitment_info: Option<(PublicKey, u32, u64, u64)>,
	/// Initial counterparty commitment transaction
	///
	/// We previously used the field above to re-build the counterparty commitment transaction,
	/// we now provide the transaction outright.
	initial_counterparty_commitment_tx: Option<CommitmentTransaction>,

	/// The first block height at which we had no remaining claimable balances.
	balances_empty_height: Option<u32>,

	/// In-memory only HTLC ids used to track upstream HTLCs that have been failed backwards due to
	/// a downstream channel force-close remaining unconfirmed by the time the upstream timeout
	/// expires. This is used to tell us we already generated an event to fail this HTLC back
	/// during a previous block scan.
	failed_back_htlc_ids: HashSet<SentHTLCId>,

	// The auxiliary HTLC data associated with a holder commitment transaction. This includes
	// non-dust HTLC sources, along with dust HTLCs and their sources. Note that this assumes any
	// alternative holder commitment transactions, like in the case of splicing, must maintain the
	// same set of non-dust and dust HTLCs. Also, while non-dust HTLC indices might change across
	// commitment transactions, their ordering with respect to each other must remain the same.
	current_holder_htlc_data: CommitmentHTLCData,
	prev_holder_htlc_data: Option<CommitmentHTLCData>,

	// Upon confirmation, tracks the txid and confirmation height of a renegotiated funding
	// transaction found in `Self::pending_funding`. Used to determine which commitment we should
	// broadcast when necessary.
	//
	// "Alternative" in this context means a `FundingScope` other than the currently locked one
	// found at `Self::funding`. We don't use the term "renegotiated", as the currently locked
	// `FundingScope` could be one that was renegotiated.
	alternative_funding_confirmed: Option<(Txid, u32)>,

	/// [`ChannelMonitor`]s written by LDK prior to 0.1 need to be re-persisted after startup. To
	/// make deciding whether to do so simple, here we track whether this monitor was last written
	/// prior to 0.1.
	written_by_0_1_or_later: bool,
}

// Returns a `&FundingScope` for the one we are currently observing/handling commitment transactions
// for on the chain.
macro_rules! get_confirmed_funding_scope {
	($self: expr) => {
		$self
			.alternative_funding_confirmed
			.map(|(alternative_funding_txid, _)| {
				$self
					.pending_funding
					.iter()
					.find(|funding| funding.funding_txid() == alternative_funding_txid)
					.expect("FundingScope for confirmed alternative funding must exist")
			})
			.unwrap_or(&$self.funding)
	};
}

// Macro helper to access holder commitment HTLC data (including both non-dust and dust) while
// holding mutable references to `self`. Unfortunately, if these were turned into helper functions,
// we'd be unable to mutate `self` while holding an immutable iterator (specifically, returned from
// a function) over `self`.
#[rustfmt::skip]
macro_rules! holder_commitment_htlcs {
	($self: expr, CURRENT) => {{
		let funding = get_confirmed_funding_scope!($self);
		funding.current_holder_commitment_tx.nondust_htlcs().iter()
			.chain($self.current_holder_htlc_data.dust_htlcs.iter().map(|(htlc, _)| htlc))
	}};
	($self: expr, CURRENT_WITH_SOURCES) => {{
		let funding = get_confirmed_funding_scope!($self);
		holder_commitment_htlcs!(
			&funding.current_holder_commitment_tx, &$self.current_holder_htlc_data
		)
	}};
	($self: expr, PREV) => {{
		let funding = get_confirmed_funding_scope!($self);
		funding.prev_holder_commitment_tx.as_ref().map(|tx| {
			let dust_htlcs = $self.prev_holder_htlc_data.as_ref().unwrap().dust_htlcs.iter()
				.map(|(htlc, _)| htlc);
			tx.nondust_htlcs().iter().chain(dust_htlcs)
		})
	}};
	($self: expr, PREV_WITH_SOURCES) => {{
		let funding = get_confirmed_funding_scope!($self);
		funding.prev_holder_commitment_tx.as_ref().map(|tx| {
			holder_commitment_htlcs!(tx, $self.prev_holder_htlc_data.as_ref().unwrap())
		})
	}};
	($commitment_tx: expr, $htlc_data: expr) => {{
		let mut sources = $htlc_data.nondust_htlc_sources.iter();
		let nondust_htlcs = $commitment_tx.nondust_htlcs().iter().map(move |htlc| {
			let mut source = None;
			if htlc.offered {
				debug_assert!(htlc.transaction_output_index.is_some());
				source = sources.next();
				if source.is_none() {
					panic!("Every offered non-dust HTLC should have a corresponding source");
				}
			}
			(htlc, source)
		});
		let dust_htlcs = $htlc_data.dust_htlcs.iter().map(|(htlc, source)| (htlc, source.as_ref()));
		nondust_htlcs.chain(dust_htlcs)
	}};
}

/// Transaction outputs to watch for on-chain spends.
pub type TransactionOutputs = (Txid, Vec<(u32, TxOut)>);

// Because we have weird workarounds for `ChannelMonitor` equality checks in `OnchainTxHandler` and
// `PackageTemplate` the equality implementation isn't really fit for public consumption. Instead,
// we only expose it during tests.
#[cfg(any(feature = "_test_utils", test))]
impl<Signer: EcdsaChannelSigner> PartialEq for ChannelMonitor<Signer>
where
	Signer: PartialEq,
{
	fn eq(&self, other: &Self) -> bool {
		use crate::sync::LockTestExt;
		// We need some kind of total lockorder. Absent a better idea, we sort by position in
		// memory and take locks in that order (assuming that we can't move within memory while a
		// lock is held).
		let ord = ((self as *const _) as usize) < ((other as *const _) as usize);
		let a = if ord {
			self.inner.unsafe_well_ordered_double_lock_self()
		} else {
			other.inner.unsafe_well_ordered_double_lock_self()
		};
		let b = if ord {
			other.inner.unsafe_well_ordered_double_lock_self()
		} else {
			self.inner.unsafe_well_ordered_double_lock_self()
		};
		a.eq(&b)
	}
}

impl<Signer: EcdsaChannelSigner> Writeable for ChannelMonitor<Signer> {
	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
		self.inner.lock().unwrap().write(writer)
	}
}

// These are also used for ChannelMonitorUpdate, above.
const SERIALIZATION_VERSION: u8 = 1;
const MIN_SERIALIZATION_VERSION: u8 = 1;

/// Utility function for writing [`ChannelMonitor`] to prevent code duplication in [`ChainMonitor`] while sending Peer Storage.
///
/// NOTE: `is_stub` is true only when we are using this to serialise for Peer Storage.
///
/// TODO: Determine which fields of each `ChannelMonitor` should be included in Peer Storage, and which should be omitted.
///
/// [`ChainMonitor`]: crate::chain::chainmonitor::ChainMonitor
pub(crate) fn write_chanmon_internal<Signer: EcdsaChannelSigner, W: Writer>(
	channel_monitor: &ChannelMonitorImpl<Signer>, _is_stub: bool, writer: &mut W,
) -> Result<(), Error> {
	write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);

	channel_monitor.latest_update_id.write(writer)?;

	// Set in initial Channel-object creation, so should always be set by now:
	U48(channel_monitor.commitment_transaction_number_obscure_factor).write(writer)?;

	channel_monitor.destination_script.write(writer)?;
	if let Some(ref broadcasted_holder_revokable_script) =
		channel_monitor.broadcasted_holder_revokable_script
	{
		writer.write_all(&[0; 1])?;
		broadcasted_holder_revokable_script.0.write(writer)?;
		broadcasted_holder_revokable_script.1.write(writer)?;
		broadcasted_holder_revokable_script.2.write(writer)?;
	} else {
		writer.write_all(&[1; 1])?;
	}

	channel_monitor.counterparty_payment_script.write(writer)?;
	match &channel_monitor.shutdown_script {
		Some(script) => script.write(writer)?,
		None => ScriptBuf::new().write(writer)?,
	}

	channel_monitor.channel_keys_id.write(writer)?;
	channel_monitor.holder_revocation_basepoint.write(writer)?;
	let funding_outpoint = channel_monitor.get_funding_txo();
	writer.write_all(&funding_outpoint.txid[..])?;
	writer.write_all(&funding_outpoint.index.to_be_bytes())?;
	let redeem_script = channel_monitor.funding.channel_parameters.make_funding_redeemscript();
	let script_pubkey = redeem_script.to_p2wsh();
	script_pubkey.write(writer)?;
	channel_monitor.funding.current_counterparty_commitment_txid.write(writer)?;
	channel_monitor.funding.prev_counterparty_commitment_txid.write(writer)?;

	channel_monitor.counterparty_commitment_params.write(writer)?;
	redeem_script.write(writer)?;
	channel_monitor.funding.channel_parameters.channel_value_satoshis.write(writer)?;

	match channel_monitor.their_cur_per_commitment_points {
		Some((idx, pubkey, second_option)) => {
			writer.write_all(&byte_utils::be48_to_array(idx))?;
			writer.write_all(&pubkey.serialize())?;
			match second_option {
				Some(second_pubkey) => {
					writer.write_all(&second_pubkey.serialize())?;
				},
				None => {
					writer.write_all(&[0; 33])?;
				},
			}
		},
		None => {
			writer.write_all(&byte_utils::be48_to_array(0))?;
		},
	}

	writer.write_all(&channel_monitor.on_holder_tx_csv.to_be_bytes())?;

	channel_monitor.commitment_secrets.write(writer)?;

	#[rustfmt::skip]
	macro_rules! serialize_htlc_in_commitment {
		($htlc_output: expr) => {
			writer.write_all(&[$htlc_output.offered as u8; 1])?;
			writer.write_all(&$htlc_output.amount_msat.to_be_bytes())?;
			writer.write_all(&$htlc_output.cltv_expiry.to_be_bytes())?;
			writer.write_all(&$htlc_output.payment_hash.0[..])?;
			$htlc_output.transaction_output_index.write(writer)?;
		}
	}

	writer.write_all(
		&(channel_monitor.funding.counterparty_claimable_outpoints.len() as u64).to_be_bytes(),
	)?;
	for (ref txid, ref htlc_infos) in
		channel_monitor.funding.counterparty_claimable_outpoints.iter()
	{
		writer.write_all(&txid[..])?;
		writer.write_all(&(htlc_infos.len() as u64).to_be_bytes())?;
		for &(ref htlc_output, ref htlc_source) in htlc_infos.iter() {
			debug_assert!(
				htlc_source.is_none()
					|| Some(**txid) == channel_monitor.funding.current_counterparty_commitment_txid
					|| Some(**txid) == channel_monitor.funding.prev_counterparty_commitment_txid,
				"HTLC Sources for all revoked commitment transactions should be none!"
			);
			serialize_htlc_in_commitment!(htlc_output);
			htlc_source.as_ref().map(|b| b.as_ref()).write(writer)?;
		}
	}

	writer.write_all(
		&(channel_monitor.counterparty_commitment_txn_on_chain.len() as u64).to_be_bytes(),
	)?;
	for (ref txid, commitment_number) in channel_monitor.counterparty_commitment_txn_on_chain.iter()
	{
		writer.write_all(&txid[..])?;
		writer.write_all(&byte_utils::be48_to_array(*commitment_number))?;
	}

	writer.write_all(
		&(channel_monitor.counterparty_hash_commitment_number.len() as u64).to_be_bytes(),
	)?;
	for (ref payment_hash, commitment_number) in
		channel_monitor.counterparty_hash_commitment_number.iter()
	{
		writer.write_all(&payment_hash.0[..])?;
		writer.write_all(&byte_utils::be48_to_array(*commitment_number))?;
	}

	if let Some(holder_commitment_tx) = &channel_monitor.funding.prev_holder_commitment_tx {
		writer.write_all(&[1; 1])?;
		write_legacy_holder_commitment_data(
			writer,
			holder_commitment_tx,
			&channel_monitor.prev_holder_htlc_data.as_ref().unwrap(),
		)?;
	} else {
		writer.write_all(&[0; 1])?;
	}

	write_legacy_holder_commitment_data(
		writer,
		&channel_monitor.funding.current_holder_commitment_tx,
		&channel_monitor.current_holder_htlc_data,
	)?;

	writer.write_all(&byte_utils::be48_to_array(
		channel_monitor.current_counterparty_commitment_number,
	))?;
	writer
		.write_all(&byte_utils::be48_to_array(channel_monitor.current_holder_commitment_number))?;

	writer.write_all(&(channel_monitor.payment_preimages.len() as u64).to_be_bytes())?;
	for (payment_preimage, _) in channel_monitor.payment_preimages.values() {
		writer.write_all(&payment_preimage.0[..])?;
	}

	writer.write_all(
		&(channel_monitor
			.pending_monitor_events
			.iter()
			.filter(|ev| match ev {
				MonitorEvent::HTLCEvent(_) => true,
				MonitorEvent::HolderForceClosed(_) => true,
				MonitorEvent::HolderForceClosedWithInfo { .. } => true,
				_ => false,
			})
			.count() as u64)
			.to_be_bytes(),
	)?;
	for event in channel_monitor.pending_monitor_events.iter() {
		match event {
			MonitorEvent::HTLCEvent(upd) => {
				0u8.write(writer)?;
				upd.write(writer)?;
			},
			MonitorEvent::HolderForceClosed(_) => 1u8.write(writer)?,
			// `HolderForceClosedWithInfo` replaced `HolderForceClosed` in v0.0.122. To keep
			// backwards compatibility, we write a `HolderForceClosed` event along with the
			// `HolderForceClosedWithInfo` event. This is deduplicated in the reader.
			MonitorEvent::HolderForceClosedWithInfo { .. } => 1u8.write(writer)?,
			_ => {}, // Covered in the TLV writes below
		}
	}

	writer.write_all(&(channel_monitor.pending_events.len() as u64).to_be_bytes())?;
	for event in channel_monitor.pending_events.iter() {
		event.write(writer)?;
	}

	channel_monitor.best_block.block_hash.write(writer)?;
	writer.write_all(&channel_monitor.best_block.height.to_be_bytes())?;

	writer.write_all(
		&(channel_monitor.onchain_events_awaiting_threshold_conf.len() as u64).to_be_bytes(),
	)?;
	for ref entry in channel_monitor.onchain_events_awaiting_threshold_conf.iter() {
		entry.write(writer)?;
	}

	(channel_monitor.outputs_to_watch.len() as u64).write(writer)?;
	for (txid, idx_scripts) in channel_monitor.outputs_to_watch.iter() {
		txid.write(writer)?;
		(idx_scripts.len() as u64).write(writer)?;
		for (idx, script) in idx_scripts.iter() {
			idx.write(writer)?;
			script.write(writer)?;
		}
	}

	channel_monitor.onchain_tx_handler.write(writer)?;

	channel_monitor.lockdown_from_offchain.write(writer)?;
	channel_monitor.holder_tx_signed.write(writer)?;

	// If we have a `HolderForceClosedWithInfo` event, we need to write the `HolderForceClosed` for backwards compatibility.
	let pending_monitor_events =
		match channel_monitor.pending_monitor_events.iter().find(|ev| match ev {
			MonitorEvent::HolderForceClosedWithInfo { .. } => true,
			_ => false,
		}) {
			Some(MonitorEvent::HolderForceClosedWithInfo { outpoint, .. }) => {
				let mut pending_monitor_events = channel_monitor.pending_monitor_events.clone();
				pending_monitor_events.push(MonitorEvent::HolderForceClosed(*outpoint));
				pending_monitor_events
			},
			_ => channel_monitor.pending_monitor_events.clone(),
		};

	write_tlv_fields!(writer, {
		(1, channel_monitor.funding_spend_confirmed, option),
		(3, channel_monitor.htlcs_resolved_on_chain, required_vec),
		(5, pending_monitor_events, required_vec),
		(7, channel_monitor.funding_spend_seen, required),
		(9, channel_monitor.counterparty_node_id, required),
		(11, channel_monitor.confirmed_commitment_tx_counterparty_output, option),
		(13, channel_monitor.spendable_txids_confirmed, required_vec),
		(15, channel_monitor.counterparty_fulfilled_htlcs, required),
		(17, channel_monitor.initial_counterparty_commitment_info, option),
		(19, channel_monitor.channel_id, required),
		(21, channel_monitor.balances_empty_height, option),
		(23, channel_monitor.holder_pays_commitment_tx_fee, option),
		(25, channel_monitor.payment_preimages, required),
		(27, channel_monitor.first_negotiated_funding_txo, required),
		(29, channel_monitor.initial_counterparty_commitment_tx, option),
		(31, channel_monitor.funding.channel_parameters, required),
		(32, channel_monitor.pending_funding, optional_vec),
		(33, channel_monitor.htlcs_resolved_to_user, required),
		(34, channel_monitor.alternative_funding_confirmed, option),
		(35, channel_monitor.is_manual_broadcast, required),
		(37, channel_monitor.funding_seen_onchain, required),
	});

	Ok(())
}

impl<Signer: EcdsaChannelSigner> Writeable for ChannelMonitorImpl<Signer> {
	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
		write_chanmon_internal(self, false, writer)
	}
}

#[rustfmt::skip]
macro_rules! _process_events_body {
	($self_opt: expr, $logger: expr, $event_to_handle: expr, $handle_event: expr) => {
		loop {
			let mut handling_res = Ok(());
			let (pending_events, repeated_events);
			if let Some(us) = $self_opt {
				let mut inner = us.inner.lock().unwrap();
				if inner.is_processing_pending_events {
					break handling_res;
				}
				inner.is_processing_pending_events = true;

				pending_events = inner.pending_events.clone();
				repeated_events = inner.get_repeated_events();
			} else { break handling_res; }

			let mut num_handled_events = 0;
			for event in pending_events {
				log_trace!($logger, "Handling event {:?}...", event);
				$event_to_handle = event;
				let event_handling_result = $handle_event;
				log_trace!($logger, "Done handling event, result: {:?}", event_handling_result);
				match event_handling_result {
					Ok(()) => num_handled_events += 1,
					Err(e) => {
						// If we encounter an error we stop handling events and make sure to replay
						// any unhandled events on the next invocation.
						handling_res = Err(e);
						break;
					}
				}
			}

			if handling_res.is_ok() {
				for event in repeated_events {
					// For repeated events we ignore any errors as they will be replayed eventually
					// anyways.
					$event_to_handle = event;
					let _ = $handle_event;
				}
			}

			if let Some(us) = $self_opt {
				let mut inner = us.inner.lock().unwrap();
				inner.pending_events.drain(..num_handled_events);
				inner.is_processing_pending_events = false;
				if handling_res.is_ok() && !inner.pending_events.is_empty() {
					// If there's more events to process and we didn't fail so far, go ahead and do
					// so.
					continue;
				}
			}
			break handling_res;
		}
	}
}
pub(super) use _process_events_body as process_events_body;

pub(crate) struct WithChannelMonitor;

impl WithChannelMonitor {
	pub(crate) fn from<'a, L: Logger, S: EcdsaChannelSigner>(
		logger: &'a L, monitor: &ChannelMonitor<S>, payment_hash: Option<PaymentHash>,
	) -> WithContext<'a, L> {
		Self::from_impl(logger, &*monitor.inner.lock().unwrap(), payment_hash)
	}

	pub(crate) fn from_impl<'a, L: Logger, S: EcdsaChannelSigner>(
		logger: &'a L, monitor_impl: &ChannelMonitorImpl<S>, payment_hash: Option<PaymentHash>,
	) -> WithContext<'a, L> {
		let peer_id = Some(monitor_impl.counterparty_node_id);
		let channel_id = Some(monitor_impl.channel_id());
		WithContext::from(logger, peer_id, channel_id, payment_hash)
	}
}

impl<Signer: EcdsaChannelSigner> ChannelMonitor<Signer> {
	/// For lockorder enforcement purposes, we need to have a single site which constructs the
	/// `inner` mutex, otherwise cases where we lock two monitors at the same time (eg in our
	/// PartialEq implementation) we may decide a lockorder violation has occurred.
	fn from_impl(imp: ChannelMonitorImpl<Signer>) -> Self {
		ChannelMonitor { inner: Mutex::new(imp) }
	}

	#[rustfmt::skip]
	pub(crate) fn new(
		secp_ctx: Secp256k1<secp256k1::All>, keys: Signer, shutdown_script: Option<ScriptBuf>,
		on_counterparty_tx_csv: u16, destination_script: &Script,
		channel_parameters: &ChannelTransactionParameters, holder_pays_commitment_tx_fee: bool,
		commitment_transaction_number_obscure_factor: u64,
		initial_holder_commitment_tx: HolderCommitmentTransaction, best_block: BestBlock,
		counterparty_node_id: PublicKey, channel_id: ChannelId,
		is_manual_broadcast: bool,
	) -> ChannelMonitor<Signer> {

		assert!(commitment_transaction_number_obscure_factor <= (1 << 48));
		let holder_pubkeys = &channel_parameters.holder_pubkeys;
		let counterparty_payment_script = chan_utils::get_countersigner_payment_script(
			&channel_parameters.channel_type_features, &holder_pubkeys.payment_point
		);

		let counterparty_channel_parameters = channel_parameters.counterparty_parameters.as_ref().unwrap();
		let counterparty_delayed_payment_base_key = counterparty_channel_parameters.pubkeys.delayed_payment_basepoint;
		let counterparty_htlc_base_key = counterparty_channel_parameters.pubkeys.htlc_basepoint;
		let counterparty_commitment_params = CounterpartyCommitmentParameters { counterparty_delayed_payment_base_key, counterparty_htlc_base_key, on_counterparty_tx_csv };

		let channel_keys_id = keys.channel_keys_id();
		let holder_revocation_basepoint = holder_pubkeys.revocation_basepoint;

		let current_holder_commitment_number =
			initial_holder_commitment_tx.trust().commitment_number();

		let onchain_tx_handler = OnchainTxHandler::new(
			channel_id, counterparty_node_id, channel_parameters.channel_value_satoshis,
			channel_keys_id, destination_script.into(), keys, channel_parameters.clone(),
			initial_holder_commitment_tx.clone(), secp_ctx,
		);

		let funding_outpoint = channel_parameters.funding_outpoint
			.expect("Funding outpoint must be known during initialization");
		let funding_redeem_script = channel_parameters.make_funding_redeemscript();
		let funding_script = funding_redeem_script.to_p2wsh();
		let mut outputs_to_watch = new_hash_map();
		outputs_to_watch.insert(
			funding_outpoint.txid, vec![(funding_outpoint.index as u32, funding_script.clone())],
		);

		Self::from_impl(ChannelMonitorImpl {
			funding: FundingScope {
				channel_parameters: channel_parameters.clone(),

				current_counterparty_commitment_txid: None,
				prev_counterparty_commitment_txid: None,
				counterparty_claimable_outpoints: new_hash_map(),

				current_holder_commitment_tx: initial_holder_commitment_tx,
				prev_holder_commitment_tx: None,
			},
			pending_funding: vec![],

			is_manual_broadcast,
			funding_seen_onchain: false,

			latest_update_id: 0,
			commitment_transaction_number_obscure_factor,

			destination_script: destination_script.into(),
			broadcasted_holder_revokable_script: None,
			counterparty_payment_script,
			shutdown_script,

			channel_keys_id,
			holder_revocation_basepoint,
			channel_id,
			first_negotiated_funding_txo: funding_outpoint,

			counterparty_commitment_params,
			their_cur_per_commitment_points: None,

			on_holder_tx_csv: counterparty_channel_parameters.selected_contest_delay,

			commitment_secrets: CounterpartyCommitmentSecrets::new(),
			counterparty_commitment_txn_on_chain: new_hash_map(),
			counterparty_hash_commitment_number: new_hash_map(),
			counterparty_fulfilled_htlcs: new_hash_map(),

			current_counterparty_commitment_number: 1 << 48,
			current_holder_commitment_number,

			payment_preimages: new_hash_map(),
			pending_monitor_events: Vec::new(),
			pending_events: Vec::new(),
			is_processing_pending_events: false,

			onchain_events_awaiting_threshold_conf: Vec::new(),
			outputs_to_watch,

			onchain_tx_handler,

			holder_pays_commitment_tx_fee: Some(holder_pays_commitment_tx_fee),
			lockdown_from_offchain: false,
			holder_tx_signed: false,
			funding_spend_seen: false,
			funding_spend_confirmed: None,
			confirmed_commitment_tx_counterparty_output: None,
			htlcs_resolved_on_chain: Vec::new(),
			htlcs_resolved_to_user: new_hash_set(),
			spendable_txids_confirmed: Vec::new(),

			best_block,
			counterparty_node_id: counterparty_node_id,
			initial_counterparty_commitment_info: None,
			initial_counterparty_commitment_tx: None,
			balances_empty_height: None,

			failed_back_htlc_ids: new_hash_set(),

			// There are never any HTLCs in the initial commitment transaction
			current_holder_htlc_data: CommitmentHTLCData::new(),
			prev_holder_htlc_data: None,

			alternative_funding_confirmed: None,

			written_by_0_1_or_later: true,
		})
	}

	/// Returns a unique id for persisting the [`ChannelMonitor`], which is used as a key in a
	/// key-value store.
	///
	/// Note: Previously, the funding outpoint was used in the [`Persist`] trait. However, since the
	/// outpoint may change during splicing, this method is used to obtain a unique key instead. For
	/// v1 channels, the funding outpoint is still used for backwards compatibility, whereas v2
	/// channels use the channel id since it is fixed.
	///
	/// [`Persist`]: crate::chain::chainmonitor::Persist
	pub fn persistence_key(&self) -> MonitorName {
		let inner = self.inner.lock().unwrap();
		let funding_outpoint = inner.first_negotiated_funding_txo;
		let channel_id = inner.channel_id;
		if ChannelId::v1_from_funding_outpoint(funding_outpoint) == channel_id {
			MonitorName::V1Channel(funding_outpoint)
		} else {
			MonitorName::V2Channel(channel_id)
		}
	}

	#[cfg(test)]
	fn provide_secret(&self, idx: u64, secret: [u8; 32]) -> Result<(), &'static str> {
		self.inner.lock().unwrap().provide_secret(idx, secret)
	}

	/// A variant of `Self::provide_latest_counterparty_commitment_tx` used to provide
	/// the counterparty commitment transaction to the monitor so that the transaction
	/// can be retrieved during the initial persistence of the monitor (mainly for use in
	/// third-party watchtowers).
	///
	/// This is used to provide the counterparty commitment transaction directly to the monitor
	/// before the initial persistence of a new channel.
	pub(crate) fn provide_initial_counterparty_commitment_tx(
		&self, commitment_tx: CommitmentTransaction,
	) {
		let mut inner = self.inner.lock().unwrap();
		inner.provide_initial_counterparty_commitment_tx(commitment_tx);
	}

	/// Informs this monitor of the latest counterparty (ie non-broadcastable) commitment transaction.
	/// The monitor watches for it to be broadcasted and then uses the HTLC information (and
	/// possibly future revocation/preimage information) to claim outputs where possible.
	/// We cache also the mapping hash:commitment number to lighten pruning of old preimages by watchtowers.
	#[cfg(test)]
	fn provide_latest_counterparty_commitment_tx(
		&self, txid: Txid, htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Box<HTLCSource>>)>,
		commitment_number: u64, their_per_commitment_point: PublicKey,
	) {
		let mut inner = self.inner.lock().unwrap();
		inner.provide_latest_counterparty_commitment_tx(
			txid,
			htlc_outputs,
			commitment_number,
			their_per_commitment_point,
		)
	}

	#[cfg(test)]
	#[rustfmt::skip]
	fn provide_latest_holder_commitment_tx(
		&self, holder_commitment_tx: HolderCommitmentTransaction,
		htlc_outputs: &[(HTLCOutputInCommitment, Option<Signature>, Option<HTLCSource>)],
	) {
		self.inner.lock().unwrap().provide_latest_holder_commitment_tx(
			holder_commitment_tx, htlc_outputs, &Vec::new(), Vec::new(),
		).unwrap()
	}

	/// This is used to provide payment preimage(s) out-of-band during startup without updating the
	/// off-chain state with a new commitment transaction.
	///
	/// It is used only for legacy (created prior to LDK 0.1) pending payments on upgrade, and the
	/// flow that uses it assumes that this [`ChannelMonitor`] is persisted prior to the
	/// [`ChannelManager`] being persisted (as the state necessary to call this method again is
	/// removed from the [`ChannelManager`] and thus a persistence inversion would imply we do not
	/// get the preimage back into this [`ChannelMonitor`] on startup).
	///
	/// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
	#[rustfmt::skip]
	pub(crate) fn provide_payment_preimage_unsafe_legacy<B: BroadcasterInterface, F: FeeEstimator, L: Logger>(
		&self,
		payment_hash: &PaymentHash,
		payment_preimage: &PaymentPreimage,
		broadcaster: &B,
		fee_estimator: &LowerBoundedFeeEstimator<F>,
		logger: &L,
	) {
		let mut inner = self.inner.lock().unwrap();
		let logger = WithChannelMonitor::from_impl(logger, &*inner, Some(*payment_hash));
		// Note that we don't pass any MPP claim parts here. This is generally not okay but in this
		// case is acceptable as we only call this method from `ChannelManager` deserialization in
		// cases where we are replaying a claim started on a previous version of LDK.
		inner.provide_payment_preimage(
			payment_hash, payment_preimage, &None, broadcaster, fee_estimator, &logger)
	}

	/// Updates a ChannelMonitor on the basis of some new information provided by the Channel
	/// itself.
	///
	/// panics if the given update is not the next update by update_id.
	pub fn update_monitor<B: BroadcasterInterface, F: FeeEstimator, L: Logger>(
		&self, updates: &ChannelMonitorUpdate, broadcaster: &B, fee_estimator: &F, logger: &L,
	) -> Result<(), ()> {
		let mut inner = self.inner.lock().unwrap();
		let logger = WithChannelMonitor::from_impl(logger, &*inner, None);
		inner.update_monitor(updates, broadcaster, fee_estimator, &logger)
	}

	/// Gets the update_id from the latest ChannelMonitorUpdate which was applied to this
	/// ChannelMonitor.
	///
	/// Note that for channels closed prior to LDK 0.1, this may return [`u64::MAX`].
	pub fn get_latest_update_id(&self) -> u64 {
		self.inner.lock().unwrap().get_latest_update_id()
	}

	/// Gets the funding transaction outpoint of the channel this ChannelMonitor is monitoring for.
	pub fn get_funding_txo(&self) -> OutPoint {
		self.inner.lock().unwrap().get_funding_txo()
	}

	pub(crate) fn written_by_0_1_or_later(&self) -> bool {
		self.inner.lock().unwrap().written_by_0_1_or_later
	}

	/// Gets the funding script of the channel this ChannelMonitor is monitoring for.
	pub fn get_funding_script(&self) -> ScriptBuf {
		self.inner.lock().unwrap().get_funding_script()
	}

	/// Gets the channel_id of the channel this ChannelMonitor is monitoring for.
	pub fn channel_id(&self) -> ChannelId {
		self.inner.lock().unwrap().channel_id()
	}

	/// Gets the channel type of the corresponding channel.
	pub fn channel_type_features(&self) -> ChannelTypeFeatures {
		self.inner.lock().unwrap().channel_type_features().clone()
	}

	/// Gets a list of txids, with their output scripts (in the order they appear in the
	/// transaction), which we must learn about spends of via block_connected().
	#[rustfmt::skip]
	pub fn get_outputs_to_watch(&self) -> Vec<(Txid, Vec<(u32, ScriptBuf)>)> {
		self.inner.lock().unwrap().get_outputs_to_watch()
			.iter().map(|(txid, outputs)| (*txid, outputs.clone())).collect()
	}

	/// Loads the funding txo and outputs to watch into the given `chain::Filter` by repeatedly
	/// calling `chain::Filter::register_output` and `chain::Filter::register_tx` until all outputs
	/// have been registered.
	#[rustfmt::skip]
	pub fn load_outputs_to_watch<F: chain::Filter, L: Logger>(&self, filter: &F, logger: &L) {
		let lock = self.inner.lock().unwrap();
		let logger = WithChannelMonitor::from_impl(logger, &*lock, None);
		for funding in core::iter::once(&lock.funding).chain(&lock.pending_funding) {
			let funding_outpoint = funding.funding_outpoint();
			log_trace!(&logger, "Registering funding outpoint {} with the filter to monitor confirmations", &funding_outpoint);
			let script_pubkey = funding.channel_parameters.make_funding_redeemscript().to_p2wsh();
			filter.register_tx(&funding_outpoint.txid, &script_pubkey);
		}
		for (txid, outputs) in lock.get_outputs_to_watch().iter() {
			for (index, script_pubkey) in outputs.iter() {
				assert!(*index <= u16::MAX as u32);
				let outpoint = OutPoint { txid: *txid, index: *index as u16 };
				log_trace!(logger, "Registering outpoint {} with the filter to monitor spend", outpoint);
				filter.register_output(WatchedOutput {
					block_hash: None,
					outpoint,
					script_pubkey: script_pubkey.clone(),
				});
			}
		}
	}

	/// Get the list of HTLCs who's status has been updated on chain. This should be called by
	/// ChannelManager via [`chain::Watch::release_pending_monitor_events`].
	pub fn get_and_clear_pending_monitor_events(&self) -> Vec<MonitorEvent> {
		self.inner.lock().unwrap().get_and_clear_pending_monitor_events()
	}

	/// Processes [`SpendableOutputs`] events produced from each [`ChannelMonitor`] upon maturity.
	///
	/// For channels featuring anchor outputs, this method will also process [`BumpTransaction`]
	/// events produced from each [`ChannelMonitor`] while there is a balance to claim onchain
	/// within each channel. As the confirmation of a commitment transaction may be critical to the
	/// safety of funds, we recommend invoking this every 30 seconds, or lower if running in an
	/// environment with spotty connections, like on mobile.
	///
	/// An [`EventHandler`] may safely call back to the provider, though this shouldn't be needed in
	/// order to handle these events.
	///
	/// Will return a [`ReplayEvent`] error if event handling failed and should eventually be retried.
	///
	/// [`SpendableOutputs`]: crate::events::Event::SpendableOutputs
	/// [`BumpTransaction`]: crate::events::Event::BumpTransaction
	pub fn process_pending_events<H: Deref, L: Logger>(
		&self, handler: &H, logger: &L,
	) -> Result<(), ReplayEvent>
	where
		H::Target: EventHandler,
	{
		let mut ev;
		process_events_body!(Some(self), logger, ev, handler.handle_event(ev))
	}

	/// Processes any events asynchronously.
	///
	/// See [`Self::process_pending_events`] for more information.
	pub async fn process_pending_events_async<
		Future: core::future::Future<Output = Result<(), ReplayEvent>>,
		H: Fn(Event) -> Future,
		L: Logger,
	>(
		&self, handler: &H, logger: &L,
	) -> Result<(), ReplayEvent> {
		let mut ev;
		process_events_body!(Some(self), logger, ev, { handler(ev).await })
	}

	#[cfg(test)]
	pub fn get_and_clear_pending_events(&self) -> Vec<Event> {
		let mut ret = Vec::new();
		let mut lck = self.inner.lock().unwrap();
		mem::swap(&mut ret, &mut lck.pending_events);
		ret.append(&mut lck.get_repeated_events());
		ret
	}

	/// Gets the counterparty's initial commitment transaction. The returned commitment
	/// transaction is unsigned. This is intended to be called during the initial persistence of
	/// the monitor (inside an implementation of [`Persist::persist_new_channel`]), to allow for
	/// watchtowers in the persistence pipeline to have enough data to form justice transactions.
	///
	/// This is similar to [`Self::counterparty_commitment_txs_from_update`], except
	/// that for the initial commitment transaction, we don't have a corresponding update.
	///
	/// This will only return `Some` for channel monitors that have been created after upgrading
	/// to LDK 0.0.117+.
	///
	/// [`Persist::persist_new_channel`]: crate::chain::chainmonitor::Persist::persist_new_channel
	pub fn initial_counterparty_commitment_tx(&self) -> Option<CommitmentTransaction> {
		self.inner.lock().unwrap().initial_counterparty_commitment_tx()
	}

	/// Gets all of the counterparty commitment transactions provided by the given update. This
	/// may be empty if the update doesn't include any new counterparty commitments. Returned
	/// commitment transactions are unsigned.
	///
	/// This is provided so that watchtower clients in the persistence pipeline are able to build
	/// justice transactions for each counterparty commitment upon each update. It's intended to be
	/// used within an implementation of [`Persist::update_persisted_channel`], which is provided
	/// with a monitor and an update. Once revoked, signing a justice transaction can be done using
	/// [`Self::sign_to_local_justice_tx`].
	///
	/// It is expected that a watchtower client may use this method to retrieve the latest counterparty
	/// commitment transaction(s), and then hold the necessary data until a later update in which
	/// the monitor has been updated with the corresponding revocation data, at which point the
	/// monitor can sign the justice transaction.
	///
	/// This will only return a non-empty list for monitor updates that have been created after
	/// upgrading to LDK 0.0.117+. Note that no restriction lies on the monitors themselves, which
	/// may have been created prior to upgrading.
	///
	/// [`Persist::update_persisted_channel`]: crate::chain::chainmonitor::Persist::update_persisted_channel
	pub fn counterparty_commitment_txs_from_update(
		&self, update: &ChannelMonitorUpdate,
	) -> Vec<CommitmentTransaction> {
		self.inner.lock().unwrap().counterparty_commitment_txs_from_update(update)
	}

	/// Wrapper around [`EcdsaChannelSigner::sign_justice_revoked_output`] to make
	/// signing the justice transaction easier for implementors of
	/// [`chain::chainmonitor::Persist`]. On success this method returns the provided transaction
	/// signing the input at `input_idx`. This method will only produce a valid signature for
	/// a transaction spending the `to_local` output of a commitment transaction, i.e. this cannot
	/// be used for revoked HTLC outputs.
	///
	/// `Value` is the value of the output being spent by the input at `input_idx`, committed
	/// in the BIP 143 signature.
	///
	/// This method will only succeed if this monitor has received the revocation secret for the
	/// provided `commitment_number`. If a commitment number is provided that does not correspond
	/// to the commitment transaction being revoked, this will return a signed transaction, but
	/// the signature will not be valid.
	///
	/// Note that due to splicing, this can also return an `Err` when the counterparty commitment
	/// this transaction is attempting to claim is no longer valid because the corresponding funding
	/// transaction was spliced.
	///
	/// [`EcdsaChannelSigner::sign_justice_revoked_output`]: crate::sign::ecdsa::EcdsaChannelSigner::sign_justice_revoked_output
	/// [`Persist`]: crate::chain::chainmonitor::Persist
	#[rustfmt::skip]
	pub fn sign_to_local_justice_tx(&self, justice_tx: Transaction, input_idx: usize, value: u64, commitment_number: u64) -> Result<Transaction, ()> {
		self.inner.lock().unwrap().sign_to_local_justice_tx(justice_tx, input_idx, value, commitment_number)
	}

	pub(crate) fn get_min_seen_secret(&self) -> u64 {
		self.inner.lock().unwrap().get_min_seen_secret()
	}

	pub(crate) fn get_cur_counterparty_commitment_number(&self) -> u64 {
		self.inner.lock().unwrap().get_cur_counterparty_commitment_number()
	}

	pub(crate) fn get_cur_holder_commitment_number(&self) -> u64 {
		self.inner.lock().unwrap().get_cur_holder_commitment_number()
	}

	/// Fetches whether this monitor has marked the channel as closed and will refuse any further
	/// updates to the commitment transactions.
	///
	/// It can be marked closed in a few different ways, including via a
	/// [`ChannelMonitorUpdateStep::ChannelForceClosed`] or if the channel has been closed
	/// on-chain.
	pub(crate) fn no_further_updates_allowed(&self) -> bool {
		self.inner.lock().unwrap().no_further_updates_allowed()
	}

	/// Gets the `node_id` of the counterparty for this channel.
	pub fn get_counterparty_node_id(&self) -> PublicKey {
		self.inner.lock().unwrap().counterparty_node_id
	}

	/// You may use this to broadcast the latest local commitment transaction, either because
	/// a monitor update failed or because we've fallen behind (i.e. we've received proof that our
	/// counterparty side knows a revocation secret we gave them that they shouldn't know).
	///
	/// Broadcasting these transactions in this manner is UNSAFE, as they allow counterparty
	/// side to punish you. Nevertheless you may want to broadcast them if counterparty doesn't
	/// close channel with their commitment transaction after a substantial amount of time. Best
	/// may be to contact the other node operator out-of-band to coordinate other options available
	/// to you.
	///
	/// Note: For channels using manual funding broadcast (see
	/// [`crate::ln::channelmanager::ChannelManager::funding_transaction_generated_manual_broadcast`]),
	/// automatic broadcasts are suppressed until the funding transaction has been observed on-chain.
	/// Calling this method overrides that suppression and queues the latest holder commitment
	/// transaction for broadcast even if the funding has not yet been seen on-chain. This may result
	/// in unconfirmable transactions being broadcast or [`Event::BumpTransaction`] notifications for
	/// transactions that cannot be confirmed until the funding transaction is visible.
	///
	/// [`Event::BumpTransaction`]: crate::events::Event::BumpTransaction
	pub fn broadcast_latest_holder_commitment_txn<
		B: BroadcasterInterface,
		F: FeeEstimator,
		L: Logger,
	>(
		&self, broadcaster: &B, fee_estimator: &F, logger: &L,
	) {
		let mut inner = self.inner.lock().unwrap();
		let fee_estimator = LowerBoundedFeeEstimator::new(fee_estimator);
		let logger = WithChannelMonitor::from_impl(logger, &*inner, None);

		inner.queue_latest_holder_commitment_txn_for_broadcast(
			broadcaster,
			&fee_estimator,
			&logger,
			false,
		);
	}

	/// Unsafe test-only version of `broadcast_latest_holder_commitment_txn` used by our test framework
	/// to bypass HolderCommitmentTransaction state update lockdown after signature and generate
	/// revoked commitment transaction.
	#[cfg(any(test, feature = "_test_utils", feature = "unsafe_revoked_tx_signing"))]
	pub fn unsafe_get_latest_holder_commitment_txn<L: Logger>(
		&self, logger: &L,
	) -> Vec<Transaction> {
		let mut inner = self.inner.lock().unwrap();
		let logger = WithChannelMonitor::from_impl(logger, &*inner, None);
		inner.unsafe_get_latest_holder_commitment_txn(&logger)
	}

	/// Processes transactions in a newly connected block, which may result in any of the following:
	/// - update the monitor's state against resolved HTLCs
	/// - punish the counterparty in the case of seeing a revoked commitment transaction
	/// - force close the channel and claim/timeout incoming/outgoing HTLCs if near expiration
	/// - detect settled outputs for later spending
	/// - schedule and bump any in-flight claims
	///
	/// Returns any new outputs to watch from `txdata`; after called, these are also included in
	/// [`get_outputs_to_watch`].
	///
	/// [`get_outputs_to_watch`]: #method.get_outputs_to_watch
	#[rustfmt::skip]
	pub fn block_connected<B: BroadcasterInterface, F: FeeEstimator, L: Logger>(
		&self,
		header: &Header,
		txdata: &TransactionData,
		height: u32,
		broadcaster: B,
		fee_estimator: F,
		logger: &L,
	) -> Vec<TransactionOutputs> {
		let mut inner = self.inner.lock().unwrap();
		let logger = WithChannelMonitor::from_impl(logger, &*inner, None);
		inner.block_connected(
			header, txdata, height, broadcaster, fee_estimator, &logger)
	}

	/// Determines if the disconnected block contained any transactions of interest and updates
	/// appropriately.
	pub fn blocks_disconnected<B: BroadcasterInterface, F: FeeEstimator, L: Logger>(
		&self, fork_point: BestBlock, broadcaster: B, fee_estimator: F, logger: &L,
	) {
		let mut inner = self.inner.lock().unwrap();
		let logger = WithChannelMonitor::from_impl(logger, &*inner, None);
		inner.blocks_disconnected(fork_point, broadcaster, fee_estimator, &logger)
	}

	/// Processes transactions confirmed in a block with the given header and height, returning new
	/// outputs to watch. See [`block_connected`] for details.
	///
	/// Used instead of [`block_connected`] by clients that are notified of transactions rather than
	/// blocks. See [`chain::Confirm`] for calling expectations.
	///
	/// [`block_connected`]: Self::block_connected
	#[rustfmt::skip]
	pub fn transactions_confirmed<B: BroadcasterInterface, F: FeeEstimator, L: Logger>(
		&self,
		header: &Header,
		txdata: &TransactionData,
		height: u32,
		broadcaster: B,
		fee_estimator: F,
		logger: &L,
	) -> Vec<TransactionOutputs> {
		let bounded_fee_estimator = LowerBoundedFeeEstimator::new(fee_estimator);
		let mut inner = self.inner.lock().unwrap();
		let logger = WithChannelMonitor::from_impl(logger, &*inner, None);
		inner.transactions_confirmed(
			header, txdata, height, broadcaster, &bounded_fee_estimator, &logger)
	}

	/// Processes a transaction that was reorganized out of the chain.
	///
	/// Used instead of [`blocks_disconnected`] by clients that are notified of transactions rather
	/// than blocks. See [`chain::Confirm`] for calling expectations.
	///
	/// [`blocks_disconnected`]: Self::blocks_disconnected
	#[rustfmt::skip]
	pub fn transaction_unconfirmed<B: BroadcasterInterface, F: FeeEstimator, L: Logger>(
		&self,
		txid: &Txid,
		broadcaster: B,
		fee_estimator: F,
		logger: &L,
	) {
		let bounded_fee_estimator = LowerBoundedFeeEstimator::new(fee_estimator);
		let mut inner = self.inner.lock().unwrap();
		let logger = WithChannelMonitor::from_impl(logger, &*inner, None);
		inner.transaction_unconfirmed(
			txid, broadcaster, &bounded_fee_estimator, &logger
		);
	}

	/// Updates the monitor with the current best chain tip, returning new outputs to watch. See
	/// [`block_connected`] for details.
	///
	/// Used instead of [`block_connected`] by clients that are notified of transactions rather than
	/// blocks. See [`chain::Confirm`] for calling expectations.
	///
	/// [`block_connected`]: Self::block_connected
	#[rustfmt::skip]
	pub fn best_block_updated<B: BroadcasterInterface, F: FeeEstimator, L: Logger>(
		&self,
		header: &Header,
		height: u32,
		broadcaster: B,
		fee_estimator: F,
		logger: &L,
	) -> Vec<TransactionOutputs> {
		let bounded_fee_estimator = LowerBoundedFeeEstimator::new(fee_estimator);
		let mut inner = self.inner.lock().unwrap();
		let logger = WithChannelMonitor::from_impl(logger, &*inner, None);
		inner.best_block_updated(
			header, height, broadcaster, &bounded_fee_estimator, &logger
		)
	}

	/// Returns the set of txids that should be monitored for re-organization out of the chain.
	#[rustfmt::skip]
	pub fn get_relevant_txids(&self) -> Vec<(Txid, u32, Option<BlockHash>)> {
		let inner = self.inner.lock().unwrap();
		let mut txids: Vec<(Txid, u32, Option<BlockHash>)> = inner.onchain_events_awaiting_threshold_conf
			.iter()
			.map(|entry| (entry.txid, entry.height, entry.block_hash))
			.chain(inner.onchain_tx_handler.get_relevant_txids().into_iter())
			.collect();
		txids.sort_unstable_by(|a, b| a.0.cmp(&b.0).then(b.1.cmp(&a.1)));
		txids.dedup_by_key(|(txid, _, _)| *txid);
		txids
	}

	/// Gets the latest best block which was connected either via the [`chain::Listen`] or
	/// [`chain::Confirm`] interfaces.
	pub fn current_best_block(&self) -> BestBlock {
		self.inner.lock().unwrap().best_block.clone()
	}

	/// Triggers rebroadcasts/fee-bumps of pending claims from a force-closed channel. This is
	/// crucial in preventing certain classes of pinning attacks, detecting substantial mempool
	/// feerate changes between blocks, and ensuring reliability if broadcasting fails. We recommend
	/// invoking this every 30 seconds, or lower if running in an environment with spotty
	/// connections, like on mobile.
	#[rustfmt::skip]
	pub fn rebroadcast_pending_claims<B: BroadcasterInterface, F: FeeEstimator, L: Logger>(
		&self, broadcaster: B, fee_estimator: F, logger: &L,
	) {
		let fee_estimator = LowerBoundedFeeEstimator::new(fee_estimator);
		let mut lock = self.inner.lock().unwrap();
		let inner = &mut *lock;
		let logger = WithChannelMonitor::from_impl(logger, &*inner, None);
		let current_height = inner.best_block.height;
		let conf_target = inner.closure_conf_target();
		inner.onchain_tx_handler.rebroadcast_pending_claims(
			current_height, FeerateStrategy::HighestOfPreviousOrNew, &broadcaster, conf_target,
			&inner.destination_script, &fee_estimator, &logger,
		);
	}

	/// Returns true if the monitor has pending claim requests that are not fully confirmed yet.
	pub fn has_pending_claims(&self) -> bool {
		self.inner.lock().unwrap().onchain_tx_handler.has_pending_claims()
	}

	/// Triggers rebroadcasts of pending claims from a force-closed channel after a transaction
	/// signature generation failure.
	#[rustfmt::skip]
	pub fn signer_unblocked<B: BroadcasterInterface, F: FeeEstimator, L: Logger>(
		&self, broadcaster: B, fee_estimator: F, logger: &L,
	) {
		let fee_estimator = LowerBoundedFeeEstimator::new(fee_estimator);
		let mut lock = self.inner.lock().unwrap();
		let inner = &mut *lock;
		let logger = WithChannelMonitor::from_impl(logger, &*inner, None);
		let current_height = inner.best_block.height;
		let conf_target = inner.closure_conf_target();
		inner.onchain_tx_handler.rebroadcast_pending_claims(
			current_height, FeerateStrategy::RetryPrevious, &broadcaster, conf_target,
			&inner.destination_script, &fee_estimator, &logger,
		);
	}

	/// Returns the descriptors for relevant outputs (i.e., those that we can spend) within the
	/// transaction if they exist and the transaction has at least [`ANTI_REORG_DELAY`]
	/// confirmations. For [`SpendableOutputDescriptor::DelayedPaymentOutput`] descriptors to be
	/// returned, the transaction must have at least `max(ANTI_REORG_DELAY, to_self_delay)`
	/// confirmations.
	///
	/// Descriptors returned by this method are primarily exposed via [`Event::SpendableOutputs`]
	/// once they are no longer under reorg risk. This method serves as a way to retrieve these
	/// descriptors at a later time, either for historical purposes, or to replay any
	/// missed/unhandled descriptors. For the purpose of gathering historical records, if the
	/// channel close has fully resolved (i.e., [`ChannelMonitor::get_claimable_balances`] returns
	/// an empty set), you can retrieve all spendable outputs by providing all descendant spending
	/// transactions starting from the channel's funding transaction and going down three levels.
	///
	/// `tx` is a transaction we'll scan the outputs of. Any transaction can be provided. If any
	/// outputs which can be spent by us are found, at least one descriptor is returned.
	///
	/// `confirmation_height` must be the height of the block in which `tx` was included in.
	#[rustfmt::skip]
	pub fn get_spendable_outputs(&self, tx: &Transaction, confirmation_height: u32) -> Vec<SpendableOutputDescriptor> {
		let inner = self.inner.lock().unwrap();
		let current_height = inner.best_block.height;
		let funding = get_confirmed_funding_scope!(inner);
		let mut spendable_outputs = inner.get_spendable_outputs(&funding, tx);
		spendable_outputs.retain(|descriptor| {
			let mut conf_threshold = current_height.saturating_sub(ANTI_REORG_DELAY) + 1;
			if let SpendableOutputDescriptor::DelayedPaymentOutput(descriptor) = descriptor {
				conf_threshold = cmp::min(conf_threshold,
					current_height.saturating_sub(descriptor.to_self_delay as u32) + 1);
			}
			conf_threshold >= confirmation_height
		});
		spendable_outputs
	}

	/// Checks if the monitor is fully resolved. Resolved monitor is one that has claimed all of
	/// its outputs and balances (i.e. [`Self::get_claimable_balances`] returns an empty set) and
	/// which does not have any payment preimages for HTLCs which are still pending on other
	/// channels.
	///
	/// Additionally may update state to track when the balances set became empty.
	///
	/// This function returns a tuple of two booleans, the first indicating whether the monitor is
	/// fully resolved, and the second whether the monitor needs persistence to ensure it is
	/// reliably marked as resolved within [`ARCHIVAL_DELAY_BLOCKS`] blocks.
	///
	/// The first boolean is true only if [`Self::get_claimable_balances`] has been empty for at
	/// least [`ARCHIVAL_DELAY_BLOCKS`] blocks as an additional protection against any bugs
	/// resulting in spuriously empty balance sets.
	#[rustfmt::skip]
	pub fn check_and_update_full_resolution_status<L: Logger>(&self, logger: &L) -> (bool, bool) {
		let mut is_all_funds_claimed = self.get_claimable_balances().is_empty();
		let current_height = self.current_best_block().height;
		let mut inner = self.inner.lock().unwrap();

		if inner.is_closed_without_updates()
			&& is_all_funds_claimed
			&& !inner.funding_spend_seen
		{
			// We closed the channel without ever advancing it and didn't have any funds in it.
			// We should immediately archive this monitor as there's nothing for us to ever do with
			// it.
			return (true, false);
		}

		if is_all_funds_claimed && !inner.funding_spend_seen {
			debug_assert!(false, "We should see funding spend by the time a monitor clears out");
			is_all_funds_claimed = false;
		}

		// As long as HTLCs remain unresolved, they'll be present as a `Balance`. After that point,
		// if they contained a preimage, an event will appear in `pending_monitor_events` which,
		// once processed, implies the preimage exists in the corresponding inbound channel.
		let preimages_not_needed_elsewhere = inner.pending_monitor_events.is_empty();

		match (inner.balances_empty_height, is_all_funds_claimed, preimages_not_needed_elsewhere) {
			(Some(balances_empty_height), true, true) => {
				// Claimed all funds, check if reached the blocks threshold.
				(current_height >= balances_empty_height + ARCHIVAL_DELAY_BLOCKS, false)
			},
			(Some(_), false, _)|(Some(_), _, false) => {
				// previously assumed we claimed all funds, but we have new funds to claim or
				// preimages are suddenly needed (because of a duplicate-hash HTLC).
				// This should never happen as once the `Balance`s and preimages are clear, we
				// should never create new ones.
				debug_assert!(false,
					"Thought we were done claiming funds, but claimable_balances now has entries");
				log_error!(logger,
					"WARNING: LDK thought it was done claiming all the available funds in the ChannelMonitor for channel {}, but later decided it had more to claim. This is potentially an important bug in LDK, please report it at https://github.com/lightningdevkit/rust-lightning/issues/new",
					inner.get_funding_txo());
				inner.balances_empty_height = None;
				(false, true)
			},
			(None, true, true) => {
				// Claimed all funds and preimages can be deleted, but `balances_empty_height` is
				// None. It is set to the current block height.
				log_debug!(logger,
					"ChannelMonitor funded at {} is now fully resolved. It will become archivable in {} blocks",
					inner.get_funding_txo(), ARCHIVAL_DELAY_BLOCKS);
				inner.balances_empty_height = Some(current_height);
				(false, true)
			},
			(None, false, _)|(None, _, false) => {
				// Have funds to claim or our preimages are still needed.
				(false, false)
			},
		}
	}

	#[cfg(test)]
	pub fn get_counterparty_payment_script(&self) -> ScriptBuf {
		self.inner.lock().unwrap().counterparty_payment_script.clone()
	}

	#[cfg(test)]
	pub fn set_counterparty_payment_script(&self, script: ScriptBuf) {
		self.inner.lock().unwrap().counterparty_payment_script = script;
	}

	#[cfg(any(test, feature = "_test_utils"))]
	pub fn do_mut_signer_call<F: FnMut(&mut Signer) -> ()>(&self, mut f: F) {
		let mut inner = self.inner.lock().unwrap();
		f(&mut inner.onchain_tx_handler.signer);
	}
}

impl<Signer: EcdsaChannelSigner> ChannelMonitorImpl<Signer> {
	/// Helper for get_claimable_balances which does the work for an individual HTLC, generating up
	/// to one `Balance` for the HTLC.
	#[rustfmt::skip]
	fn get_htlc_balance(&self, htlc: &HTLCOutputInCommitment, source: Option<&HTLCSource>,
		holder_commitment: bool, counterparty_revoked_commitment: bool,
		confirmed_txid: Option<Txid>
	) -> Option<Balance> {
		let htlc_commitment_tx_output_idx = htlc.transaction_output_index?;

		let mut htlc_spend_txid_opt = None;
		let mut htlc_spend_tx_opt = None;
		let mut holder_timeout_spend_pending = None;
		let mut htlc_spend_pending = None;
		let mut holder_delayed_output_pending = None;
		for event in self.onchain_events_awaiting_threshold_conf.iter() {
			match event.event {
				OnchainEvent::HTLCUpdate { commitment_tx_output_idx, htlc_value_satoshis, .. }
				if commitment_tx_output_idx == Some(htlc_commitment_tx_output_idx) => {
					debug_assert!(htlc_spend_txid_opt.is_none());
					htlc_spend_txid_opt = Some(&event.txid);
					debug_assert!(htlc_spend_tx_opt.is_none());
					htlc_spend_tx_opt = event.transaction.as_ref();
					debug_assert!(holder_timeout_spend_pending.is_none());
					debug_assert_eq!(htlc_value_satoshis.unwrap(), htlc.amount_msat / 1000);
					holder_timeout_spend_pending = Some(event.confirmation_threshold());
				},
				OnchainEvent::HTLCSpendConfirmation { commitment_tx_output_idx, preimage, .. }
				if commitment_tx_output_idx == htlc_commitment_tx_output_idx => {
					debug_assert!(htlc_spend_txid_opt.is_none());
					htlc_spend_txid_opt = Some(&event.txid);
					debug_assert!(htlc_spend_tx_opt.is_none());
					htlc_spend_tx_opt = event.transaction.as_ref();
					debug_assert!(htlc_spend_pending.is_none());
					htlc_spend_pending = Some((event.confirmation_threshold(), preimage.is_some()));
				},
				OnchainEvent::MaturingOutput {
					descriptor: SpendableOutputDescriptor::DelayedPaymentOutput(ref descriptor) }
				if event.transaction.as_ref().map(|tx| tx.input.iter().enumerate()
					.any(|(input_idx, inp)|
						 Some(inp.previous_output.txid) == confirmed_txid &&
							inp.previous_output.vout == htlc_commitment_tx_output_idx &&
								// A maturing output for an HTLC claim will always be at the same
								// index as the HTLC input. This is true pre-anchors, as there's
								// only 1 input and 1 output. This is also true post-anchors,
								// because we have a SIGHASH_SINGLE|ANYONECANPAY signature from our
								// channel counterparty.
								descriptor.outpoint.index as usize == input_idx
					))
					.unwrap_or(false)
				=> {
					debug_assert!(holder_delayed_output_pending.is_none());
					holder_delayed_output_pending = Some(event.confirmation_threshold());
				},
				_ => {},
			}
		}
		let htlc_resolved = self.htlcs_resolved_on_chain.iter()
			.any(|v| if v.commitment_tx_output_idx == Some(htlc_commitment_tx_output_idx) {
				debug_assert!(htlc_spend_txid_opt.is_none());
				htlc_spend_txid_opt = v.resolving_txid.as_ref();
				debug_assert!(htlc_spend_tx_opt.is_none());
				htlc_spend_tx_opt = v.resolving_tx.as_ref();
				true
			} else { false });
		debug_assert!(holder_timeout_spend_pending.is_some() as u8 + htlc_spend_pending.is_some() as u8 + htlc_resolved as u8 <= 1);

		let htlc_commitment_outpoint = BitcoinOutPoint::new(confirmed_txid.unwrap(), htlc_commitment_tx_output_idx);
		let htlc_output_to_spend =
			if let Some(txid) = htlc_spend_txid_opt {
				// Because HTLC transactions either only have 1 input and 1 output (pre-anchors) or
				// are signed with SIGHASH_SINGLE|ANYONECANPAY under BIP-0143 (post-anchors), we can
				// locate the correct output by ensuring its adjacent input spends the HTLC output
				// in the commitment.
				if let Some(ref tx) = htlc_spend_tx_opt {
					let htlc_input_idx_opt = tx.input.iter().enumerate()
						.find(|(_, input)| input.previous_output == htlc_commitment_outpoint)
						.map(|(idx, _)| idx as u32);
					debug_assert!(htlc_input_idx_opt.is_some());
					BitcoinOutPoint::new(*txid, htlc_input_idx_opt.unwrap_or(0))
				} else {
					let funding = get_confirmed_funding_scope!(self);
					debug_assert!(!funding.channel_type_features().supports_anchors_zero_fee_htlc_tx());
					debug_assert!(!funding.channel_type_features().supports_anchor_zero_fee_commitments());
					BitcoinOutPoint::new(*txid, 0)
				}
			} else {
				htlc_commitment_outpoint
			};
		let htlc_output_spend_pending = self.onchain_tx_handler.is_output_spend_pending(&htlc_output_to_spend);

		if let Some(conf_thresh) = holder_delayed_output_pending {
			debug_assert!(holder_commitment);
			return Some(Balance::ClaimableAwaitingConfirmations {
				amount_satoshis: htlc.amount_msat / 1000,
				confirmation_height: conf_thresh,
				source: BalanceSource::Htlc,
			});
		} else if htlc_resolved && !htlc_output_spend_pending {
			// Funding transaction spends should be fully confirmed by the time any
			// HTLC transactions are resolved, unless we're talking about a holder
			// commitment tx, whose resolution is delayed until the CSV timeout is
			// reached, even though HTLCs may be resolved after only
			// ANTI_REORG_DELAY confirmations.
			debug_assert!(holder_commitment || self.funding_spend_confirmed.is_some());
		} else if counterparty_revoked_commitment {
			let htlc_output_claim_pending = self.onchain_events_awaiting_threshold_conf.iter().any(|event| {
				if let OnchainEvent::MaturingOutput {
					descriptor: SpendableOutputDescriptor::StaticOutput { .. }
				} = &event.event {
					event.transaction.as_ref().map(|tx| tx.input.iter().any(|inp| {
						if let Some(htlc_spend_txid) = htlc_spend_txid_opt {
							tx.compute_txid() == *htlc_spend_txid || inp.previous_output.txid == *htlc_spend_txid
						} else {
							Some(inp.previous_output.txid) == confirmed_txid &&
								inp.previous_output.vout == htlc_commitment_tx_output_idx
						}
					})).unwrap_or(false)
				} else {
					false
				}
			});
			if htlc_output_claim_pending {
				// We already push `Balance`s onto the `res` list for every
				// `StaticOutput` in a `MaturingOutput` in the revoked
				// counterparty commitment transaction case generally, so don't
				// need to do so again here.
			} else {
				debug_assert!(holder_timeout_spend_pending.is_none(),
					"HTLCUpdate OnchainEvents should never appear for preimage claims");
				debug_assert!(!htlc.offered || htlc_spend_pending.is_none() || !htlc_spend_pending.unwrap().1,
					"We don't (currently) generate preimage claims against revoked outputs, where did you get one?!");
				return Some(Balance::CounterpartyRevokedOutputClaimable {
					amount_satoshis: htlc.amount_msat / 1000,
				});
			}
		} else if htlc.offered == holder_commitment {
			// If the payment was outbound, check if there's an HTLCUpdate
			// indicating we have spent this HTLC with a timeout, claiming it back
			// and awaiting confirmations on it.
			if let Some(conf_thresh) = holder_timeout_spend_pending {
				return Some(Balance::ClaimableAwaitingConfirmations {
					amount_satoshis: htlc.amount_msat / 1000,
					confirmation_height: conf_thresh,
					source: BalanceSource::Htlc,
				});
			} else {
				let outbound_payment = match source {
					None => panic!("Outbound HTLCs should have a source"),
					Some(&HTLCSource::PreviousHopData(_)) => false,
					Some(&HTLCSource::OutboundRoute { .. }) => true,
				};
				return Some(Balance::MaybeTimeoutClaimableHTLC {
					amount_satoshis: htlc.amount_msat / 1000,
					claimable_height: htlc.cltv_expiry,
					payment_hash: htlc.payment_hash,
					outbound_payment,
				});
			}
		} else if let Some((payment_preimage, _)) = self.payment_preimages.get(&htlc.payment_hash) {
			// Otherwise (the payment was inbound), only expose it as claimable if
			// we know the preimage.
			// Note that if there is a pending claim, but it did not use the
			// preimage, we lost funds to our counterparty! We will then continue
			// to show it as ContentiousClaimable until ANTI_REORG_DELAY.
			debug_assert!(holder_timeout_spend_pending.is_none());
			if let Some((conf_thresh, true)) = htlc_spend_pending {
				return Some(Balance::ClaimableAwaitingConfirmations {
					amount_satoshis: htlc.amount_msat / 1000,
					confirmation_height: conf_thresh,
					source: BalanceSource::Htlc,
				});
			} else {
				return Some(Balance::ContentiousClaimable {
					amount_satoshis: htlc.amount_msat / 1000,
					timeout_height: htlc.cltv_expiry,
					payment_hash: htlc.payment_hash,
					payment_preimage: *payment_preimage,
				});
			}
		} else if !htlc_resolved {
			return Some(Balance::MaybePreimageClaimableHTLC {
				amount_satoshis: htlc.amount_msat / 1000,
				expiry_height: htlc.cltv_expiry,
				payment_hash: htlc.payment_hash,
			});
		}
		None
	}
}

impl<Signer: EcdsaChannelSigner> ChannelMonitor<Signer> {
	/// Gets the balances in this channel which are either claimable by us if we were to
	/// force-close the channel now or which are claimable on-chain (possibly awaiting
	/// confirmation).
	///
	/// Any balances in the channel which are available on-chain (excluding on-chain fees) are
	/// included here until an [`Event::SpendableOutputs`] event has been generated for the
	/// balance, or until our counterparty has claimed the balance and accrued several
	/// confirmations on the claim transaction.
	///
	/// Note that for `ChannelMonitors` which track a channel which went on-chain with versions of
	/// LDK prior to 0.0.111, not all or excess balances may be included.
	///
	/// See [`Balance`] for additional details on the types of claimable balances which
	/// may be returned here and their meanings.
	#[rustfmt::skip]
	pub fn get_claimable_balances(&self) -> Vec<Balance> {
		let mut res = Vec::new();
		let us = self.inner.lock().unwrap();

		let mut confirmed_txid = us.funding_spend_confirmed;
		let mut confirmed_counterparty_output = us.confirmed_commitment_tx_counterparty_output;
		let mut pending_commitment_tx_conf_thresh = None;
		let funding_spend_pending = us.onchain_events_awaiting_threshold_conf.iter().find_map(|event| {
			if let OnchainEvent::FundingSpendConfirmation { commitment_tx_to_counterparty_output, .. } =
				event.event
			{
				confirmed_counterparty_output = commitment_tx_to_counterparty_output;
				Some((event.txid, event.confirmation_threshold()))
			} else { None }
		});
		if let Some((txid, conf_thresh)) = funding_spend_pending {
			debug_assert!(us.funding_spend_confirmed.is_none(),
				"We have a pending funding spend awaiting anti-reorg confirmation, we can't have confirmed it already!");
			confirmed_txid = Some(txid);
			pending_commitment_tx_conf_thresh = Some(conf_thresh);
		}

		macro_rules! walk_htlcs {
			($holder_commitment: expr, $counterparty_revoked_commitment: expr, $htlc_iter: expr) => {
				for (htlc, source) in $htlc_iter {
					if htlc.transaction_output_index.is_some() {

						if let Some(bal) = us.get_htlc_balance(
							htlc, source, $holder_commitment, $counterparty_revoked_commitment, confirmed_txid
						) {
							res.push(bal);
						}
					}
				}
			}
		}

		if let Some(txid) = confirmed_txid {
			let funding_spent = get_confirmed_funding_scope!(us);
			let mut found_commitment_tx = false;
			if let Some(counterparty_tx_htlcs) = funding_spent.counterparty_claimable_outpoints.get(&txid) {
				// First look for the to_remote output back to us.
				if let Some(conf_thresh) = pending_commitment_tx_conf_thresh {
					if let Some(value) = us.onchain_events_awaiting_threshold_conf.iter().find_map(|event| {
						if let OnchainEvent::MaturingOutput {
							descriptor: SpendableOutputDescriptor::StaticPaymentOutput(descriptor)
						} = &event.event {
							Some(descriptor.output.value)
						} else { None }
					}) {
						res.push(Balance::ClaimableAwaitingConfirmations {
							amount_satoshis: value.to_sat(),
							confirmation_height: conf_thresh,
							source: BalanceSource::CounterpartyForceClosed,
						});
					} else {
						// If a counterparty commitment transaction is awaiting confirmation, we
						// should either have a StaticPaymentOutput MaturingOutput event awaiting
						// confirmation with the same height or have never met our dust amount.
					}
				}
				if Some(txid) == funding_spent.current_counterparty_commitment_txid || Some(txid) == funding_spent.prev_counterparty_commitment_txid {
					walk_htlcs!(false, false, counterparty_tx_htlcs.iter().map(|(a, b)| (a, b.as_ref().map(|b| &**b))));
				} else {
					walk_htlcs!(false, true, counterparty_tx_htlcs.iter().map(|(a, b)| (a, b.as_ref().map(|b| &**b))));
					// The counterparty broadcasted a revoked state!
					// Look for any StaticOutputs first, generating claimable balances for those.
					// If any match the confirmed counterparty revoked to_self output, skip
					// generating a CounterpartyRevokedOutputClaimable.
					let mut spent_counterparty_output = false;
					for event in us.onchain_events_awaiting_threshold_conf.iter() {
						if let OnchainEvent::MaturingOutput {
							descriptor: SpendableOutputDescriptor::StaticOutput { output, .. }
						} = &event.event {
							res.push(Balance::ClaimableAwaitingConfirmations {
								amount_satoshis: output.value.to_sat(),
								confirmation_height: event.confirmation_threshold(),
								source: BalanceSource::CounterpartyForceClosed,
							});
							if let Some(confirmed_to_self_idx) = confirmed_counterparty_output.map(|(idx, _)| idx) {
								if event.transaction.as_ref().map(|tx|
									tx.input.iter().any(|inp| inp.previous_output.vout == confirmed_to_self_idx)
								).unwrap_or(false) {
									spent_counterparty_output = true;
								}
							}
						}
					}

					if spent_counterparty_output {
					} else if let Some((confirmed_to_self_idx, amt)) = confirmed_counterparty_output {
						let output_spendable = us.onchain_tx_handler
							.is_output_spend_pending(&BitcoinOutPoint::new(txid, confirmed_to_self_idx));
						if output_spendable {
							res.push(Balance::CounterpartyRevokedOutputClaimable {
								amount_satoshis: amt.to_sat(),
							});
						}
					} else {
						// Counterparty output is missing, either it was broadcasted on a
						// previous version of LDK or the counterparty hadn't met dust.
					}
				}
				found_commitment_tx = true;
			} else if txid == funding_spent.current_holder_commitment_tx.trust().txid() {
				walk_htlcs!(true, false, holder_commitment_htlcs!(us, CURRENT_WITH_SOURCES));
				if let Some(conf_thresh) = pending_commitment_tx_conf_thresh {
					res.push(Balance::ClaimableAwaitingConfirmations {
						amount_satoshis: funding_spent.current_holder_commitment_tx.to_broadcaster_value_sat(),
						confirmation_height: conf_thresh,
						source: BalanceSource::HolderForceClosed,
					});
				}
				found_commitment_tx = true;
			} else if let Some(prev_holder_commitment_tx) = &funding_spent.prev_holder_commitment_tx {
				if txid == prev_holder_commitment_tx.trust().txid() {
					walk_htlcs!(true, false, holder_commitment_htlcs!(us, PREV_WITH_SOURCES).unwrap());
					if let Some(conf_thresh) = pending_commitment_tx_conf_thresh {
						res.push(Balance::ClaimableAwaitingConfirmations {
							amount_satoshis: prev_holder_commitment_tx.to_broadcaster_value_sat(),
							confirmation_height: conf_thresh,
							source: BalanceSource::HolderForceClosed,
						});
					}
					found_commitment_tx = true;
				}
			}
			if !found_commitment_tx {
				if let Some(conf_thresh) = pending_commitment_tx_conf_thresh {
					// We blindly assume this is a cooperative close transaction here, and that
					// neither us nor our counterparty misbehaved. At worst we've under-estimated
					// the amount we can claim as we'll punish a misbehaving counterparty.
					res.push(Balance::ClaimableAwaitingConfirmations {
						amount_satoshis: funding_spent.current_holder_commitment_tx.to_broadcaster_value_sat(),
						confirmation_height: conf_thresh,
						source: BalanceSource::CoopClose,
					});
				}
			}
		} else {
			let mut claimable_inbound_htlc_value_sat = 0;
			let mut outbound_payment_htlc_rounded_msat = 0;
			let mut outbound_forwarded_htlc_rounded_msat = 0;
			let mut inbound_claiming_htlc_rounded_msat = 0;
			let mut inbound_htlc_rounded_msat = 0;
			// We share the same set of HTLCs across all scopes, so we don't need to check the other
			// scopes as it'd be redundant.
			for (htlc, source) in holder_commitment_htlcs!(us, CURRENT_WITH_SOURCES) {
				let rounded_value_msat = if htlc.transaction_output_index.is_none() {
					htlc.amount_msat
				} else { htlc.amount_msat % 1000 };
				if htlc.offered {
					let outbound_payment = match source {
						None => panic!("Outbound HTLCs should have a source"),
						Some(HTLCSource::PreviousHopData(_)) => false,
						Some(HTLCSource::OutboundRoute { .. }) => true,
					};
					if outbound_payment {
						outbound_payment_htlc_rounded_msat += rounded_value_msat;
					} else {
						outbound_forwarded_htlc_rounded_msat += rounded_value_msat;
					}
					if htlc.transaction_output_index.is_some() {
						res.push(Balance::MaybeTimeoutClaimableHTLC {
							amount_satoshis: htlc.amount_msat / 1000,
							claimable_height: htlc.cltv_expiry,
							payment_hash: htlc.payment_hash,
							outbound_payment,
						});
					}
				} else if us.payment_preimages.contains_key(&htlc.payment_hash) {
					inbound_claiming_htlc_rounded_msat += rounded_value_msat;
					if htlc.transaction_output_index.is_some() {
						claimable_inbound_htlc_value_sat += htlc.amount_msat / 1000;
					}
				} else {
					inbound_htlc_rounded_msat += rounded_value_msat;
					if htlc.transaction_output_index.is_some() {
						// As long as the HTLC is still in our latest commitment state, treat
						// it as potentially claimable, even if it has long-since expired.
						res.push(Balance::MaybePreimageClaimableHTLC {
							amount_satoshis: htlc.amount_msat / 1000,
							expiry_height: htlc.cltv_expiry,
							payment_hash: htlc.payment_hash,
						});
					}
				}
			}
			let balance_candidates = core::iter::once(&us.funding)
				.chain(us.pending_funding.iter())
				.map(|funding| {
					let to_self_value_sat = funding.current_holder_commitment_tx.to_broadcaster_value_sat();
					// In addition to `commit_tx_fee_sat`, this can also include dust HTLCs, any
					// elided anchors, and the total msat amount rounded down from non-dust HTLCs.
					let transaction_fee_satoshis = if us.holder_pays_commitment_tx_fee.unwrap_or(true) {
						let transaction = &funding.current_holder_commitment_tx.trust().built_transaction().transaction;
						let output_value_sat: u64 = transaction.output.iter().map(|txout| txout.value.to_sat()).sum();
						funding.channel_parameters.channel_value_satoshis - output_value_sat
					} else {
						0
					};
					HolderCommitmentTransactionBalance {
						amount_satoshis: to_self_value_sat + claimable_inbound_htlc_value_sat,
						transaction_fee_satoshis,
					}
				})
				.collect::<Vec<_>>();
			let confirmed_balance_candidate_index = core::iter::once(&us.funding)
				.chain(us.pending_funding.iter())
				.enumerate()
				.find(|(_, funding)| {
					us.alternative_funding_confirmed
						.map(|(funding_txid_confirmed, _)| funding.funding_txid() == funding_txid_confirmed)
						// If `alternative_funding_confirmed` is not set, we can assume the current
						// funding is confirmed.
						.unwrap_or(true)
				})
				.map(|(idx, _)| idx)
				.expect("We must have one FundingScope that is confirmed");

			// Only push a primary balance if either the channel isn't closed or we've advanced the
			// channel state machine at least once (implying there are multiple previous commitment
			// transactions) or we actually have a balance.
			// Avoiding including a `Balance` if none of these are true allows us to prune monitors
			// for chanels that were opened inbound to us but where the funding transaction never
			// confirmed at all.
			if !us.is_closed_without_updates()
				|| balance_candidates.iter().any(|bal| bal.amount_satoshis != 0)
			{
				res.push(Balance::ClaimableOnChannelClose {
					balance_candidates,
					confirmed_balance_candidate_index,
					outbound_payment_htlc_rounded_msat,
					outbound_forwarded_htlc_rounded_msat,
					inbound_claiming_htlc_rounded_msat,
					inbound_htlc_rounded_msat,
				});
			}
		}

		res
	}

	/// Gets the set of outbound HTLCs which can be (or have been) resolved by this
	/// `ChannelMonitor`. This is used to determine if an HTLC was removed from the channel prior
	/// to the `ChannelManager` having been persisted.
	pub(crate) fn get_all_current_outbound_htlcs(
		&self,
	) -> HashMap<HTLCSource, (HTLCOutputInCommitment, Option<PaymentPreimage>)> {
		let mut res = new_hash_map();
		// Just examine the available counterparty commitment transactions. See docs on
		// `fail_unbroadcast_htlcs`, below, for justification.
		let us = self.inner.lock().unwrap();
		let mut walk_counterparty_commitment = |txid| {
			if let Some(latest_outpoints) = us.funding.counterparty_claimable_outpoints.get(txid) {
				for &(ref htlc, ref source_option) in latest_outpoints.iter() {
					if let &Some(ref source) = source_option {
						let htlc_id = SentHTLCId::from_source(source);
						if !us.htlcs_resolved_to_user.contains(&htlc_id) {
							let preimage_opt =
								us.counterparty_fulfilled_htlcs.get(&htlc_id).cloned();
							res.insert((**source).clone(), (htlc.clone(), preimage_opt));
						}
					}
				}
			}
		};
		if let Some(ref txid) = us.funding.current_counterparty_commitment_txid {
			walk_counterparty_commitment(txid);
		}
		if let Some(ref txid) = us.funding.prev_counterparty_commitment_txid {
			walk_counterparty_commitment(txid);
		}
		res
	}

	/// Gets the set of outbound HTLCs which hit the chain and ultimately were claimed by us via
	/// the timeout path and reached [`ANTI_REORG_DELAY`] confirmations. This is used to determine
	/// if an HTLC has failed without the `ChannelManager` having seen it prior to being persisted.
	pub(crate) fn get_onchain_failed_outbound_htlcs(&self) -> HashMap<HTLCSource, PaymentHash> {
		let mut res = new_hash_map();
		let us = self.inner.lock().unwrap();

		// We only want HTLCs with ANTI_REORG_DELAY confirmations, which implies the commitment
		// transaction has least ANTI_REORG_DELAY confirmations for any dependent HTLC transactions
		// to have been confirmed.
		let confirmed_txid = us.funding_spend_confirmed.or_else(|| {
			us.onchain_events_awaiting_threshold_conf.iter().find_map(|event| {
				if let OnchainEvent::FundingSpendConfirmation { .. } = event.event {
					if event.height + ANTI_REORG_DELAY - 1 <= us.best_block.height {
						Some(event.txid)
					} else {
						None
					}
				} else {
					None
				}
			})
		});

		let confirmed_txid = if let Some(txid) = confirmed_txid {
			txid
		} else {
			return res;
		};

		macro_rules! walk_htlcs {
			($htlc_iter: expr) => {
				let mut walk_candidate_htlcs = |htlcs| {
					for &(ref candidate_htlc, ref candidate_source) in htlcs {
						let candidate_htlc: &HTLCOutputInCommitment = &candidate_htlc;
						let candidate_source: &Option<Box<HTLCSource>> = &candidate_source;

						let source: &HTLCSource = if let Some(source) = candidate_source {
							source
						} else {
							continue;
						};
						let htlc_id = SentHTLCId::from_source(source);
						if us.htlcs_resolved_to_user.contains(&htlc_id) {
							continue;
						}

						let confirmed = $htlc_iter.find(|(_, conf_src)| Some(source) == *conf_src);
						if let Some((confirmed_htlc, _)) = confirmed {
							let filter = |v: &&IrrevocablyResolvedHTLC| {
								v.commitment_tx_output_idx
									== confirmed_htlc.transaction_output_index
							};

							// The HTLC was included in the confirmed commitment transaction, so we
							// need to see if it has been irrevocably failed yet.
							if confirmed_htlc.transaction_output_index.is_none() {
								// Dust HTLCs are always implicitly failed once the commitment
								// transaction reaches ANTI_REORG_DELAY confirmations.
								res.insert(source.clone(), confirmed_htlc.payment_hash);
							} else if let Some(state) =
								us.htlcs_resolved_on_chain.iter().filter(filter).next()
							{
								if state.payment_preimage.is_none() {
									res.insert(source.clone(), confirmed_htlc.payment_hash);
								}
							}
						} else {
							// The HTLC was not included in the confirmed commitment transaction,
							// which has now reached ANTI_REORG_DELAY confirmations and thus the
							// HTLC has been failed.
							res.insert(source.clone(), candidate_htlc.payment_hash);
						}
					}
				};

				// We walk the set of HTLCs in the unrevoked counterparty commitment transactions (see
				// `fail_unbroadcast_htlcs` for a description of why).
				if let Some(ref txid) = us.funding.current_counterparty_commitment_txid {
					let htlcs = us.funding.counterparty_claimable_outpoints.get(txid);
					walk_candidate_htlcs(htlcs.expect("Missing tx info for latest tx"));
				}
				if let Some(ref txid) = us.funding.prev_counterparty_commitment_txid {
					let htlcs = us.funding.counterparty_claimable_outpoints.get(txid);
					walk_candidate_htlcs(htlcs.expect("Missing tx info for previous tx"));
				}
			};
		}

		let funding = get_confirmed_funding_scope!(us);

		if Some(confirmed_txid) == funding.current_counterparty_commitment_txid
			|| Some(confirmed_txid) == funding.prev_counterparty_commitment_txid
		{
			let htlcs = funding.counterparty_claimable_outpoints.get(&confirmed_txid).unwrap();
			walk_htlcs!(htlcs.iter().filter_map(|(a, b)| {
				if let &Some(ref source) = b {
					Some((a, Some(&**source)))
				} else {
					None
				}
			}));
		} else if confirmed_txid == funding.current_holder_commitment_tx.trust().txid() {
			walk_htlcs!(holder_commitment_htlcs!(us, CURRENT_WITH_SOURCES));
		} else if let Some(prev_commitment_tx) = &funding.prev_holder_commitment_tx {
			if confirmed_txid == prev_commitment_tx.trust().txid() {
				walk_htlcs!(holder_commitment_htlcs!(us, PREV_WITH_SOURCES).unwrap());
			} else {
				let htlcs_confirmed: &[(&HTLCOutputInCommitment, _)] = &[];
				walk_htlcs!(htlcs_confirmed.iter());
			}
		} else {
			let htlcs_confirmed: &[(&HTLCOutputInCommitment, _)] = &[];
			walk_htlcs!(htlcs_confirmed.iter());
		}

		res
	}

	pub(crate) fn get_stored_preimages(
		&self,
	) -> HashMap<PaymentHash, (PaymentPreimage, Vec<PaymentClaimDetails>)> {
		self.inner.lock().unwrap().payment_preimages.clone()
	}
}

/// Compares a broadcasted commitment transaction's HTLCs with those in the latest state,
/// failing any HTLCs which didn't make it into the broadcasted commitment transaction back
/// after ANTI_REORG_DELAY blocks.
///
/// We always compare against the set of HTLCs in counterparty commitment transactions, as those
/// are the commitment transactions which are generated by us. The off-chain state machine in
/// `Channel` will automatically resolve any HTLCs which were never included in a commitment
/// transaction when it detects channel closure, but it is up to us to ensure any HTLCs which were
/// included in a remote commitment transaction are failed back if they are not present in the
/// broadcasted commitment transaction.
///
/// Specifically, the removal process for HTLCs in `Channel` is always based on the counterparty
/// sending a `revoke_and_ack`, which causes us to clear `prev_counterparty_commitment_txid`. Thus,
/// as long as we examine both the current counterparty commitment transaction and, if it hasn't
/// been revoked yet, the previous one, we we will never "forget" to resolve an HTLC.
macro_rules! fail_unbroadcast_htlcs {
	($self: expr, $commitment_tx_type: expr, $commitment_txid_confirmed: expr, $commitment_tx_confirmed: expr,
	 $commitment_tx_conf_height: expr, $commitment_tx_conf_hash: expr, $confirmed_htlcs_list: expr, $logger: expr) => { {
		debug_assert_eq!($commitment_tx_confirmed.compute_txid(), $commitment_txid_confirmed);

		macro_rules! check_htlc_fails {
			($txid: expr, $commitment_tx: expr, $per_commitment_outpoints: expr) => {
				if let Some(ref latest_outpoints) = $per_commitment_outpoints {
					for &(ref htlc, ref source_option) in latest_outpoints.iter() {
						if let &Some(ref source) = source_option {
							// Check if the HTLC is present in the commitment transaction that was
							// broadcast, but not if it was below the dust limit, which we should
							// fail backwards immediately as there is no way for us to learn the
							// payment_preimage.
							// Note that if the dust limit were allowed to change between
							// commitment transactions we'd want to be check whether *any*
							// broadcastable commitment transaction has the HTLC in it, but it
							// cannot currently change after channel initialization, so we don't
							// need to here.
							let confirmed_htlcs_iter: &mut dyn Iterator<Item = (&HTLCOutputInCommitment, Option<&HTLCSource>)> = &mut $confirmed_htlcs_list;

							let mut matched_htlc = false;
							for (ref broadcast_htlc, ref broadcast_source) in confirmed_htlcs_iter {
								if broadcast_htlc.transaction_output_index.is_some() &&
									(Some(&**source) == *broadcast_source ||
									 (broadcast_source.is_none() &&
									  broadcast_htlc.payment_hash == htlc.payment_hash &&
									  broadcast_htlc.amount_msat == htlc.amount_msat)) {
									matched_htlc = true;
									break;
								}
							}
							if matched_htlc { continue; }
							if $self.counterparty_fulfilled_htlcs.get(&SentHTLCId::from_source(source)).is_some() {
								continue;
							}
							$self.onchain_events_awaiting_threshold_conf.retain(|ref entry| {
								if entry.height != $commitment_tx_conf_height { return true; }
								match entry.event {
									OnchainEvent::HTLCUpdate { source: ref update_source, .. } => {
										*update_source != **source
									},
									_ => true,
								}
							});
							let entry = OnchainEventEntry {
								txid: $commitment_txid_confirmed,
								transaction: Some($commitment_tx_confirmed.clone()),
								height: $commitment_tx_conf_height,
								block_hash: Some(*$commitment_tx_conf_hash),
								event: OnchainEvent::HTLCUpdate {
									source: (**source).clone(),
									payment_hash: htlc.payment_hash.clone(),
									htlc_value_satoshis: Some(htlc.amount_msat / 1000),
									commitment_tx_output_idx: None,
								},
							};
							log_trace!($logger, "Failing HTLC with payment_hash {} from {} counterparty commitment tx due to broadcast of {} commitment transaction {}, waiting for confirmation (at height {})",
								&htlc.payment_hash, $commitment_tx, $commitment_tx_type,
								$commitment_txid_confirmed, entry.confirmation_threshold());
							$self.onchain_events_awaiting_threshold_conf.push(entry);
						}
					}
				}
			}
		}
		if let Some(ref txid) = $self.funding.current_counterparty_commitment_txid {
			check_htlc_fails!(txid, "current", $self.funding.counterparty_claimable_outpoints.get(txid));
		}
		if let Some(ref txid) = $self.funding.prev_counterparty_commitment_txid {
			check_htlc_fails!(txid, "previous", $self.funding.counterparty_claimable_outpoints.get(txid));
		}
	} }
}

// In the `test_invalid_funding_tx` test, we need a bogus script which matches the HTLC-Accepted
// witness length match (ie is 136 bytes long). We generate one here which we also use in some
// in-line tests later.

#[cfg(any(test, feature = "_test_utils"))]
pub fn deliberately_bogus_accepted_htlc_witness_program() -> Vec<u8> {
	use bitcoin::opcodes;
	let mut ret = [opcodes::all::OP_NOP.to_u8(); 136];
	ret[131] = opcodes::all::OP_DROP.to_u8();
	ret[132] = opcodes::all::OP_DROP.to_u8();
	ret[133] = opcodes::all::OP_DROP.to_u8();
	ret[134] = opcodes::all::OP_DROP.to_u8();
	ret[135] = opcodes::OP_TRUE.to_u8();
	Vec::from(&ret[..])
}

#[cfg(any(test, feature = "_test_utils"))]
#[rustfmt::skip]
pub fn deliberately_bogus_accepted_htlc_witness() -> Vec<Vec<u8>> {
	vec![Vec::new(), Vec::new(), Vec::new(), Vec::new(), deliberately_bogus_accepted_htlc_witness_program().into()].into()
}

impl<Signer: EcdsaChannelSigner> ChannelMonitorImpl<Signer> {
	/// Gets the [`ConfirmationTarget`] we should use when selecting feerates for channel closure
	/// transactions for this channel right now.
	#[rustfmt::skip]
	fn closure_conf_target(&self) -> ConfirmationTarget {
		// Treat the sweep as urgent as long as there is at least one HTLC which is pending on a
		// valid commitment transaction.
		// TODO: This has always considered dust, but maybe it shouldn't?
		if holder_commitment_htlcs!(self, CURRENT).next().is_some() {
			return ConfirmationTarget::UrgentOnChainSweep;
		}
		if holder_commitment_htlcs!(self, PREV).map(|mut htlcs| htlcs.next().is_some()).unwrap_or(false) {
			return ConfirmationTarget::UrgentOnChainSweep;
		}
		if let Some(txid) = self.funding.current_counterparty_commitment_txid {
			if !self.funding.counterparty_claimable_outpoints.get(&txid).unwrap().is_empty() {
				return ConfirmationTarget::UrgentOnChainSweep;
			}
		}
		if let Some(txid) = self.funding.prev_counterparty_commitment_txid {
			if !self.funding.counterparty_claimable_outpoints.get(&txid).unwrap().is_empty() {
				return ConfirmationTarget::UrgentOnChainSweep;
			}
		}
		ConfirmationTarget::OutputSpendingFee
	}

	/// Inserts a revocation secret into this channel monitor. Prunes old preimages if neither
	/// needed by holder commitment transactions HTCLs nor by counterparty ones. Unless we haven't already seen
	/// counterparty commitment transaction's secret, they are de facto pruned (we can use revocation key).
	#[rustfmt::skip]
	fn provide_secret(&mut self, idx: u64, secret: [u8; 32]) -> Result<(), &'static str> {
		if let Err(()) = self.commitment_secrets.provide_secret(idx, secret) {
			return Err("Previous secret did not match new one");
		}

		// Prune HTLCs from the previous counterparty commitment tx so we don't generate failure/fulfill
		// events for now-revoked/fulfilled HTLCs.
		let mut removed_fulfilled_htlcs = false;
		let prune_htlc_sources = |funding: &mut FundingScope| {
			if let Some(txid) = funding.prev_counterparty_commitment_txid.take() {
				if funding.current_counterparty_commitment_txid.unwrap() != txid {
					let cur_claimables = funding.counterparty_claimable_outpoints.get(
						&funding.current_counterparty_commitment_txid.unwrap()).unwrap();
					// We only need to remove fulfilled HTLCs once for the first `FundingScope` we
					// come across since all `FundingScope`s share the same set of HTLC sources.
					if !removed_fulfilled_htlcs {
						for (_, ref source_opt) in funding.counterparty_claimable_outpoints.get(&txid).unwrap() {
							if let Some(source) = source_opt {
								if !cur_claimables.iter()
									.any(|(_, cur_source_opt)| cur_source_opt == source_opt)
								{
									self.counterparty_fulfilled_htlcs.remove(&SentHTLCId::from_source(source));
								}
							}
						}
						removed_fulfilled_htlcs = true;
					}
					for &mut (_, ref mut source_opt) in funding.counterparty_claimable_outpoints.get_mut(&txid).unwrap() {
						*source_opt = None;
					}
				} else {
					assert!(cfg!(fuzzing), "Commitment txids are unique outside of fuzzing, where hashes can collide");
				}
			}
		};
		core::iter::once(&mut self.funding).chain(&mut self.pending_funding).for_each(prune_htlc_sources);

		if !self.payment_preimages.is_empty() {
			let min_idx = self.get_min_seen_secret();
			let counterparty_hash_commitment_number = &mut self.counterparty_hash_commitment_number;

			self.payment_preimages.retain(|&k, _| {
				for htlc in holder_commitment_htlcs!(self, CURRENT) {
					if k == htlc.payment_hash {
						return true
					}
				}
				if let Some(htlcs) = holder_commitment_htlcs!(self, PREV) {
					for htlc in htlcs {
						if k == htlc.payment_hash {
							return true
						}
					}
				}
				let contains = if let Some(cn) = counterparty_hash_commitment_number.get(&k) {
					if *cn < min_idx {
						return true
					}
					true
				} else { false };
				if contains {
					counterparty_hash_commitment_number.remove(&k);
				}
				false
			});
		}

		Ok(())
	}

	#[rustfmt::skip]
	fn provide_initial_counterparty_commitment_tx(
		&mut self, commitment_tx: CommitmentTransaction,
	) {
		// We populate this field for downgrades
		self.initial_counterparty_commitment_info = Some((commitment_tx.per_commitment_point(),
			commitment_tx.negotiated_feerate_per_kw(), commitment_tx.to_broadcaster_value_sat(), commitment_tx.to_countersignatory_value_sat()));

		#[cfg(debug_assertions)] {
			let rebuilt_commitment_tx = self.initial_counterparty_commitment_tx().unwrap();
			debug_assert_eq!(rebuilt_commitment_tx.trust().txid(), commitment_tx.trust().txid());
		}

		self.provide_latest_counterparty_commitment_tx(commitment_tx.trust().txid(), Vec::new(), commitment_tx.commitment_number(),
				commitment_tx.per_commitment_point());
		// Soon, we will only populate this field
		self.initial_counterparty_commitment_tx = Some(commitment_tx);
	}

	#[rustfmt::skip]
	fn provide_latest_counterparty_commitment_tx(
		&mut self, txid: Txid, htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Box<HTLCSource>>)>,
		commitment_number: u64, their_per_commitment_point: PublicKey,
	) {
		// TODO: Encrypt the htlc_outputs data with the single-hash of the commitment transaction
		// so that a remote monitor doesn't learn anything unless there is a malicious close.
		// (only maybe, sadly we cant do the same for local info, as we need to be aware of
		// timeouts)
		for &(ref htlc, _) in &htlc_outputs {
			self.counterparty_hash_commitment_number.insert(htlc.payment_hash, commitment_number);
		}

		self.funding.prev_counterparty_commitment_txid = self.funding.current_counterparty_commitment_txid.take();
		self.funding.current_counterparty_commitment_txid = Some(txid);
		self.funding.counterparty_claimable_outpoints.insert(txid, htlc_outputs);
		self.current_counterparty_commitment_number = commitment_number;

		//TODO: Merge this into the other per-counterparty-transaction output storage stuff
		match self.their_cur_per_commitment_points {
			Some(old_points) => {
				if old_points.0 == commitment_number + 1 {
					self.their_cur_per_commitment_points = Some((old_points.0, old_points.1, Some(their_per_commitment_point)));
				} else if old_points.0 == commitment_number + 2 {
					if let Some(old_second_point) = old_points.2 {
						self.their_cur_per_commitment_points = Some((old_points.0 - 1, old_second_point, Some(their_per_commitment_point)));
					} else {
						self.their_cur_per_commitment_points = Some((commitment_number, their_per_commitment_point, None));
					}
				} else {
					self.their_cur_per_commitment_points = Some((commitment_number, their_per_commitment_point, None));
				}
			},
			None => {
				self.their_cur_per_commitment_points = Some((commitment_number, their_per_commitment_point, None));
			}
		}
	}

	fn update_counterparty_commitment_data(
		&mut self, commitment_txs: &[CommitmentTransaction], htlc_data: &CommitmentHTLCData,
	) -> Result<(), &'static str> {
		self.verify_matching_commitment_transactions(commitment_txs.iter())?;

		let htlcs_for_commitment = |commitment: &CommitmentTransaction| {
			debug_assert!(htlc_data.nondust_htlc_sources.len() <= commitment.nondust_htlcs().len());
			let mut nondust_htlcs = commitment.nondust_htlcs().iter();
			let mut sources = htlc_data.nondust_htlc_sources.iter();
			let nondust_htlcs = core::iter::from_fn(move || {
				let htlc = nondust_htlcs.next()?.clone();
				let source = (!htlc.offered).then(|| {
					let source = sources
						.next()
						.expect("Every inbound non-dust HTLC should have a corresponding source")
						.clone();
					Box::new(source)
				});
				Some((htlc, source))
			});

			let dust_htlcs = htlc_data.dust_htlcs.iter().map(|(htlc, source)| {
				(htlc.clone(), source.as_ref().map(|source| Box::new(source.clone())))
			});

			nondust_htlcs.chain(dust_htlcs).collect::<Vec<_>>()
		};

		let current_funding_commitment_tx = commitment_txs.first().unwrap();
		self.provide_latest_counterparty_commitment_tx(
			current_funding_commitment_tx.trust().txid(),
			htlcs_for_commitment(current_funding_commitment_tx),
			current_funding_commitment_tx.commitment_number(),
			current_funding_commitment_tx.per_commitment_point(),
		);

		for (pending_funding, commitment_tx) in
			self.pending_funding.iter_mut().zip(commitment_txs.iter().skip(1))
		{
			let commitment_txid = commitment_tx.trust().txid();
			pending_funding.prev_counterparty_commitment_txid =
				pending_funding.current_counterparty_commitment_txid.take();
			pending_funding.current_counterparty_commitment_txid = Some(commitment_txid);
			pending_funding
				.counterparty_claimable_outpoints
				.insert(commitment_txid, htlcs_for_commitment(commitment_tx));
		}

		Ok(())
	}

	/// Informs this monitor of the latest holder (ie broadcastable) commitment transaction. The
	/// monitor watches for timeouts and may broadcast it if we approach such a timeout. Thus, it
	/// is important that any clones of this channel monitor (including remote clones) by kept
	/// up-to-date as our holder commitment transaction is updated.
	/// Panics if set_on_holder_tx_csv has never been called.
	#[rustfmt::skip]
	fn provide_latest_holder_commitment_tx(
		&mut self, holder_commitment_tx: HolderCommitmentTransaction,
		htlc_outputs: &[(HTLCOutputInCommitment, Option<Signature>, Option<HTLCSource>)],
		claimed_htlcs: &[(SentHTLCId, PaymentPreimage)], mut nondust_htlc_sources: Vec<HTLCSource>,
	) -> Result<(), &'static str> {
		let dust_htlcs = if htlc_outputs.iter().any(|(_, s, _)| s.is_some()) {
			// If we have non-dust HTLCs in htlc_outputs, ensure they match the HTLCs in the
			// `holder_commitment_tx`. In the future, we'll no longer provide the redundant data
			// and just pass in source data via `nondust_htlc_sources`.
			debug_assert_eq!(htlc_outputs.iter().filter(|(_, s, _)| s.is_some()).count(), holder_commitment_tx.trust().nondust_htlcs().len());
			for (a, b) in htlc_outputs.iter().filter(|(_, s, _)| s.is_some()).map(|(h, _, _)| h).zip(holder_commitment_tx.trust().nondust_htlcs().iter()) {
				debug_assert_eq!(a, b);
			}
			debug_assert_eq!(htlc_outputs.iter().filter(|(_, s, _)| s.is_some()).count(), holder_commitment_tx.counterparty_htlc_sigs.len());
			for (a, b) in htlc_outputs.iter().filter_map(|(_, s, _)| s.as_ref()).zip(holder_commitment_tx.counterparty_htlc_sigs.iter()) {
				debug_assert_eq!(a, b);
			}

			// Backfill the non-dust HTLC sources.
			debug_assert!(nondust_htlc_sources.is_empty());
			nondust_htlc_sources.reserve_exact(holder_commitment_tx.nondust_htlcs().len());
			htlc_outputs.iter().filter_map(|(htlc, _, source)| {
				// Filter our non-dust HTLCs, while at the same time pushing their sources into
				// `nondust_htlc_sources`.
				if htlc.transaction_output_index.is_none() {
					return Some((htlc.clone(), source.clone()));
				}
				if htlc.offered {
					nondust_htlc_sources.push(source.clone().expect("Outbound HTLCs should have a source"));
				}
				None
			}).collect()
		} else {
			// If we don't have any non-dust HTLCs in htlc_outputs, assume they were all passed via
			// `nondust_htlc_sources`, building up the final htlc_outputs by combining
			// `nondust_htlc_sources` and the `holder_commitment_tx`
			{
				let mut prev = -1;
				for htlc in holder_commitment_tx.trust().nondust_htlcs().iter() {
					assert!(htlc.transaction_output_index.unwrap() as i32 > prev);
					prev = htlc.transaction_output_index.unwrap() as i32;
				}
			}

			debug_assert!(htlc_outputs.iter().all(|(htlc, _, _)| htlc.transaction_output_index.is_none()));
			debug_assert!(htlc_outputs.iter().all(|(_, sig_opt, _)| sig_opt.is_none()));
			debug_assert_eq!(holder_commitment_tx.trust().nondust_htlcs().len(), holder_commitment_tx.counterparty_htlc_sigs.len());

			let mut sources = nondust_htlc_sources.iter();
			for htlc in holder_commitment_tx.trust().nondust_htlcs().iter() {
				if htlc.offered {
					let source = sources.next().expect("Non-dust HTLC sources didn't match commitment tx");
					assert!(source.possibly_matches_output(htlc));
				}
			}
			assert!(sources.next().is_none(), "All HTLC sources should have been exhausted");

			// This only includes dust HTLCs as checked above.
			htlc_outputs.iter().map(|(htlc, _, source)| (htlc.clone(), source.clone())).collect()
		};

		let htlc_data = CommitmentHTLCData { nondust_htlc_sources, dust_htlcs };
		self.update_holder_commitment_data(vec![holder_commitment_tx], htlc_data, claimed_htlcs)
	}

	fn verify_matching_commitment_transactions<
		'a,
		I: ExactSizeIterator<Item = &'a CommitmentTransaction>,
	>(
		&self, commitment_txs: I,
	) -> Result<(), &'static str> {
		if self.pending_funding.len() + 1 != commitment_txs.len() {
			return Err("Commitment transaction count mismatch");
		}

		let mut other_commitment_tx = None::<&CommitmentTransaction>;
		for (funding, commitment_tx) in
			core::iter::once(&self.funding).chain(self.pending_funding.iter()).zip(commitment_txs)
		{
			let trusted_tx = &commitment_tx.trust().built_transaction().transaction;
			if trusted_tx.input.len() != 1 {
				return Err("Commitment transactions must only spend one input");
			}
			let funding_outpoint_spent = trusted_tx.input[0].previous_output;
			if funding_outpoint_spent != funding.funding_outpoint().into_bitcoin_outpoint() {
				return Err("Commitment transaction spends invalid funding outpoint");
			}

			if let Some(other_commitment_tx) = other_commitment_tx {
				if commitment_tx.commitment_number() != other_commitment_tx.commitment_number() {
					return Err("Commitment number mismatch");
				}
				if commitment_tx.per_commitment_point()
					!= other_commitment_tx.per_commitment_point()
				{
					return Err("Per-commitment-point mismatch");
				}
				if commitment_tx.negotiated_feerate_per_kw()
					!= other_commitment_tx.negotiated_feerate_per_kw()
				{
					return Err("Commitment fee rate mismatch");
				}
				let nondust_htlcs = commitment_tx.nondust_htlcs();
				let other_nondust_htlcs = other_commitment_tx.nondust_htlcs();
				if nondust_htlcs.len() != other_nondust_htlcs.len() {
					return Err("Non-dust HTLC count mismatch");
				}
				for (nondust_htlc, other_nondust_htlc) in
					nondust_htlcs.iter().zip(other_nondust_htlcs.iter())
				{
					if !nondust_htlc.is_data_equal(other_nondust_htlc) {
						return Err("Non-dust HTLC mismatch");
					}
				}
			}

			other_commitment_tx = Some(commitment_tx);
		}

		Ok(())
	}

	fn update_holder_commitment_data(
		&mut self, commitment_txs: Vec<HolderCommitmentTransaction>,
		mut htlc_data: CommitmentHTLCData, claimed_htlcs: &[(SentHTLCId, PaymentPreimage)],
	) -> Result<(), &'static str> {
		self.verify_matching_commitment_transactions(
			commitment_txs.iter().map(|holder_commitment_tx| holder_commitment_tx.deref()),
		)?;

		let current_funding_commitment_tx = commitment_txs.first().unwrap();
		self.current_holder_commitment_number = current_funding_commitment_tx.commitment_number();
		self.onchain_tx_handler.provide_latest_holder_tx(current_funding_commitment_tx.clone());
		for (funding, mut commitment_tx) in core::iter::once(&mut self.funding)
			.chain(self.pending_funding.iter_mut())
			.zip(commitment_txs.into_iter())
		{
			mem::swap(&mut commitment_tx, &mut funding.current_holder_commitment_tx);
			funding.prev_holder_commitment_tx = Some(commitment_tx);
		}

		mem::swap(&mut htlc_data, &mut self.current_holder_htlc_data);
		self.prev_holder_htlc_data = Some(htlc_data);

		for (claimed_htlc_id, claimed_preimage) in claimed_htlcs {
			#[cfg(debug_assertions)]
			{
				let cur_counterparty_htlcs = self
					.funding
					.counterparty_claimable_outpoints
					.get(&self.funding.current_counterparty_commitment_txid.unwrap())
					.unwrap();
				assert!(cur_counterparty_htlcs.iter().any(|(_, source_opt)| {
					if let Some(source) = source_opt {
						SentHTLCId::from_source(source) == *claimed_htlc_id
					} else {
						false
					}
				}));
			}
			self.counterparty_fulfilled_htlcs.insert(*claimed_htlc_id, *claimed_preimage);
		}

		Ok(())
	}

	/// Provides a payment_hash->payment_preimage mapping. Will be automatically pruned when all
	/// commitment_tx_infos which contain the payment hash have been revoked.
	///
	/// Note that this is often called multiple times for the same payment and must be idempotent.
	#[rustfmt::skip]
	fn provide_payment_preimage<B: BroadcasterInterface, F: FeeEstimator, L: Logger>(
		&mut self, payment_hash: &PaymentHash, payment_preimage: &PaymentPreimage,
		payment_info: &Option<PaymentClaimDetails>, broadcaster: &B,
		fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &WithContext<L>
	) {
		self.payment_preimages.entry(payment_hash.clone())
			.and_modify(|(_, payment_infos)| {
				if let Some(payment_info) = payment_info {
					if !payment_infos.contains(&payment_info) {
						payment_infos.push(payment_info.clone());
					}
				}
			})
			.or_insert_with(|| {
				(payment_preimage.clone(), payment_info.clone().into_iter().collect())
			});

		let confirmed_spend_info = self.funding_spend_confirmed
			.map(|txid| (txid, None))
			.or_else(|| {
				self.onchain_events_awaiting_threshold_conf.iter().find_map(|event| match event.event {
					OnchainEvent::FundingSpendConfirmation { .. } => Some((event.txid, Some(event.height))),
					_ => None,
				})
			});
		let (confirmed_spend_txid, confirmed_spend_height) =
			if let Some((txid, height)) = confirmed_spend_info {
				(txid, height)
			} else {
				return;
			};
		let funding_spent = get_confirmed_funding_scope!(self);

		// If the channel is force closed, try to claim the output from this preimage.
		// First check if a counterparty commitment transaction has been broadcasted:
		macro_rules! claim_htlcs {
			($commitment_number: expr, $txid: expr, $htlcs: expr) => {
				let htlc_claim_reqs = self.get_counterparty_output_claims_for_preimage(*payment_preimage, funding_spent, $commitment_number, $txid, $htlcs, confirmed_spend_height);
				let conf_target = self.closure_conf_target();
				self.onchain_tx_handler.update_claims_view_from_requests(
					htlc_claim_reqs, self.best_block.height, self.best_block.height, broadcaster,
					conf_target, &self.destination_script, fee_estimator, logger,
				);
			}
		}
		if let Some(txid) = funding_spent.current_counterparty_commitment_txid {
			if txid == confirmed_spend_txid {
				if let Some(commitment_number) = self.counterparty_commitment_txn_on_chain.get(&txid) {
					claim_htlcs!(*commitment_number, txid, funding_spent.counterparty_claimable_outpoints.get(&txid));
				} else {
					debug_assert!(false);
					log_error!(logger, "Detected counterparty commitment tx on-chain without tracking commitment number");
				}
				return;
			}
		}
		if let Some(txid) = funding_spent.prev_counterparty_commitment_txid {
			if txid == confirmed_spend_txid {
				if let Some(commitment_number) = self.counterparty_commitment_txn_on_chain.get(&txid) {
					claim_htlcs!(*commitment_number, txid, funding_spent.counterparty_claimable_outpoints.get(&txid));
				} else {
					debug_assert!(false);
					log_error!(logger, "Detected counterparty commitment tx on-chain without tracking commitment number");
				}
				return;
			}
		}

		// Then if a holder commitment transaction has been seen on-chain, broadcast transactions
		// claiming the HTLC output from each of the holder commitment transactions.
		// Note that we can't just use `self.holder_tx_signed`, because that only covers the case where
		// *we* sign a holder commitment transaction, not when e.g. a watchtower broadcasts one of our
		// holder commitment transactions.
		if self.broadcasted_holder_revokable_script.is_some() {
			let holder_commitment_tx = if funding_spent.current_holder_commitment_tx.trust().txid() == confirmed_spend_txid {
				Some(&funding_spent.current_holder_commitment_tx)
			} else if let Some(prev_holder_commitment_tx) = &funding_spent.prev_holder_commitment_tx {
				if prev_holder_commitment_tx.trust().txid() == confirmed_spend_txid {
					Some(prev_holder_commitment_tx)
				} else {
					None
				}
			} else {
				None
			};
			if let Some(holder_commitment_tx) = holder_commitment_tx {
				// Assume that the broadcasted commitment transaction confirmed in the current best
				// block. Even if not, its a reasonable metric for the bump criteria on the HTLC
				// transactions.
				let (claim_reqs, _) = self.get_broadcasted_holder_claims(
					funding_spent, holder_commitment_tx, self.best_block.height,
				);
				let conf_target = self.closure_conf_target();
				self.onchain_tx_handler.update_claims_view_from_requests(
					claim_reqs, self.best_block.height, self.best_block.height, broadcaster,
					conf_target, &self.destination_script, fee_estimator, logger,
				);
			}
		}
	}

	#[rustfmt::skip]
	fn generate_claimable_outpoints_and_watch_outputs(
		&mut self, generate_monitor_event_with_reason: Option<ClosureReason>,
		require_funding_seen: bool,
	) -> (Vec<PackageTemplate>, Vec<TransactionOutputs>) {
		let funding = get_confirmed_funding_scope!(self);
		let holder_commitment_tx = &funding.current_holder_commitment_tx;
		let funding_outp = HolderFundingOutput::build(
			holder_commitment_tx.clone(),
			funding.channel_parameters.clone(),
		);
		let funding_outpoint = funding.funding_outpoint();
		let commitment_package = PackageTemplate::build_package(
			funding_outpoint.txid.clone(), funding_outpoint.index as u32,
			PackageSolvingData::HolderFundingOutput(funding_outp),
			self.best_block.height,
		);
		let mut claimable_outpoints = vec![commitment_package];
		if let Some(reason) = generate_monitor_event_with_reason {
			let event = MonitorEvent::HolderForceClosedWithInfo {
				reason,
				outpoint: funding_outpoint,
				channel_id: self.channel_id,
			};
			self.pending_monitor_events.push(event);
		}

		// Although we aren't signing the transaction directly here, the transaction will be signed
		// in the claim that is queued to OnchainTxHandler. We set holder_tx_signed here to reject
		// new channel updates.
		self.holder_tx_signed = true;

		// In manual-broadcast mode, if we have not yet observed the funding transaction on-chain,
		// return empty vectors rather than triggering a broadcast.
		if require_funding_seen && self.is_manual_broadcast && !self.funding_seen_onchain {
			return (Vec::new(), Vec::new());
		}

		let mut watch_outputs = Vec::new();
		// In CSV anchor channels, we can't broadcast our HTLC transactions while the commitment transaction is
		// unconfirmed.
		// We'll delay doing so until we detect the confirmed commitment in `transactions_confirmed`.
		//
		// TODO: For now in 0FC channels, we also delay broadcasting any HTLC transactions until the commitment
		// transaction gets confirmed. It is nonetheless possible to add HTLC spends to the P2A spend
		// transaction while the commitment transaction is still unconfirmed.
		let zero_fee_htlcs =
			self.channel_type_features().supports_anchors_zero_fee_htlc_tx();
		let zero_fee_commitments =
			self.channel_type_features().supports_anchor_zero_fee_commitments();
		if !zero_fee_htlcs && !zero_fee_commitments {
			// Because we're broadcasting a commitment transaction, we should construct the package
			// assuming it gets confirmed in the next block. Sadly, we have code which considers
			// "not yet confirmed" things as discardable, so we cannot do that here.
			let (mut new_outpoints, _) = self.get_broadcasted_holder_claims(
				funding, holder_commitment_tx, self.best_block.height,
			);
			let new_outputs = self.get_broadcasted_holder_watch_outputs(holder_commitment_tx);
			if !new_outputs.is_empty() {
				watch_outputs.push((holder_commitment_tx.trust().txid(), new_outputs));
			}
			claimable_outpoints.append(&mut new_outpoints);
		}
		(claimable_outpoints, watch_outputs)
	}

	#[rustfmt::skip]
	/// Note: For channels where the funding transaction is being manually managed (see
	/// [`crate::ln::channelmanager::ChannelManager::funding_transaction_generated_manual_broadcast`]),
	/// this method returns without queuing any transactions until the funding transaction has been
	/// observed on-chain, unless `require_funding_seen` is `false`. This prevents attempting to
	/// broadcast unconfirmable holder commitment transactions before the funding is visible.
	/// See also [`ChannelMonitor::broadcast_latest_holder_commitment_txn`].
	///
	/// [`ChannelMonitor::broadcast_latest_holder_commitment_txn`]: crate::chain::channelmonitor::ChannelMonitor::broadcast_latest_holder_commitment_txn
	pub(crate) fn queue_latest_holder_commitment_txn_for_broadcast<B: BroadcasterInterface, F: FeeEstimator, L: Logger>(
		&mut self, broadcaster: &B, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &WithContext<L>,
		require_funding_seen: bool,
	) {
		let reason = ClosureReason::HolderForceClosed {
			broadcasted_latest_txn: Some(true),
			message: "ChannelMonitor-initiated commitment transaction broadcast".to_owned(),
		};
		let (claimable_outpoints, _) =
			self.generate_claimable_outpoints_and_watch_outputs(Some(reason), require_funding_seen);
		// In manual-broadcast mode, if `require_funding_seen` is true and we have not yet observed
		// the funding transaction on-chain, do not queue any transactions.
		if require_funding_seen && self.is_manual_broadcast && !self.funding_seen_onchain {
			log_info!(logger, "Not broadcasting holder commitment for manual-broadcast channel before funding appears on-chain");
			return;
		}
		let conf_target = self.closure_conf_target();
		self.onchain_tx_handler.update_claims_view_from_requests(
			claimable_outpoints, self.best_block.height, self.best_block.height, broadcaster,
			conf_target, &self.destination_script, fee_estimator, logger,
		);
	}

	fn renegotiated_funding<L: Logger>(
		&mut self, logger: &WithContext<L>, channel_parameters: &ChannelTransactionParameters,
		alternative_holder_commitment_tx: &HolderCommitmentTransaction,
		alternative_counterparty_commitment_tx: &CommitmentTransaction,
	) -> Result<(), ()> {
		let alternative_counterparty_commitment_txid =
			alternative_counterparty_commitment_tx.trust().txid();

		// Both the current counterparty commitment and the alternative one share the same set of
		// non-dust and dust HTLCs in the same order, though the index of each non-dust HTLC may be
		// different.
		//
		// We clone all HTLCs and their sources to use in the alternative funding scope, and update
		// each non-dust HTLC with their corresponding index in the alternative counterparty
		// commitment.
		let current_counterparty_commitment_htlcs =
			if let Some(txid) = &self.funding.current_counterparty_commitment_txid {
				self.funding.counterparty_claimable_outpoints.get(txid).unwrap()
			} else {
				debug_assert!(false);
				log_error!(
					logger,
					"Received funding renegotiation while initial funding negotiation is still pending"
				);
				return Err(());
			};
		let mut htlcs_with_sources = current_counterparty_commitment_htlcs.clone();
		let alternative_htlcs = alternative_counterparty_commitment_tx.nondust_htlcs();

		let expected_non_dust_htlc_count = htlcs_with_sources
			.iter()
			// Non-dust HTLCs always come first, so the position of the first dust HTLC is equal to
			// our non-dust HTLC count.
			.position(|(htlc, _)| htlc.transaction_output_index.is_none())
			.unwrap_or(htlcs_with_sources.len());
		if alternative_htlcs.len() != expected_non_dust_htlc_count {
			log_error!(
				logger,
				"Received alternative counterparty commitment with HTLC count mismatch"
			);
			return Err(());
		}

		for (alternative_htlc, (htlc, _)) in
			alternative_htlcs.iter().zip(htlcs_with_sources.iter_mut())
		{
			debug_assert!(htlc.transaction_output_index.is_some());
			debug_assert!(alternative_htlc.transaction_output_index.is_some());
			if !alternative_htlc.is_data_equal(htlc) {
				log_error!(
					logger,
					"Received alternative counterparty commitment with non-dust HTLC mismatch"
				);
				return Err(());
			}
			htlc.transaction_output_index = alternative_htlc.transaction_output_index;
		}

		let mut counterparty_claimable_outpoints = new_hash_map();
		counterparty_claimable_outpoints
			.insert(alternative_counterparty_commitment_txid, htlcs_with_sources);

		// TODO(splicing): Enforce any necessary RBF validity checks.
		let alternative_funding = FundingScope {
			channel_parameters: channel_parameters.clone(),
			current_counterparty_commitment_txid: Some(alternative_counterparty_commitment_txid),
			prev_counterparty_commitment_txid: None,
			counterparty_claimable_outpoints,
			current_holder_commitment_tx: alternative_holder_commitment_tx.clone(),
			prev_holder_commitment_tx: None,
		};
		let alternative_funding_outpoint = alternative_funding.funding_outpoint();

		if self
			.pending_funding
			.iter()
			.any(|funding| funding.funding_txid() == alternative_funding_outpoint.txid)
		{
			log_error!(
				logger,
				"Renegotiated funding transaction with a duplicate funding txid {}",
				alternative_funding_outpoint.txid
			);
			return Err(());
		}

		if let Some(parent_funding_txid) = channel_parameters.splice_parent_funding_txid.as_ref() {
			// Only one splice can be negotiated at a time after we've exchanged `channel_ready`
			// (implying our funding is confirmed) that spends our currently locked funding.
			if !self.pending_funding.is_empty() {
				log_error!(
					logger,
					"Negotiated splice while channel is pending channel_ready/splice_locked"
				);
				return Err(());
			}
			if *parent_funding_txid != self.funding.funding_txid() {
				log_error!(
					logger,
					"Negotiated splice that does not spend currently locked funding transaction"
				);
				return Err(());
			}
		} else if self.funding.is_splice() {
			// If we've already spliced at least once, we're no longer able to RBF the original
			// funding transaction.
			return Err(());
		}

		let script_pubkey = channel_parameters.make_funding_redeemscript().to_p2wsh();
		self.outputs_to_watch.insert(
			alternative_funding_outpoint.txid,
			vec![(alternative_funding_outpoint.index as u32, script_pubkey)],
		);
		self.pending_funding.push(alternative_funding);

		Ok(())
	}

	fn promote_funding(&mut self, new_funding_txid: Txid) -> Result<(), ()> {
		let prev_funding_txid = self.funding.funding_txid();

		let new_funding = self
			.pending_funding
			.iter_mut()
			.find(|funding| funding.funding_txid() == new_funding_txid);
		if new_funding.is_none() {
			return Err(());
		}
		let mut new_funding = new_funding.unwrap();

		mem::swap(&mut self.funding, &mut new_funding);
		self.onchain_tx_handler.update_after_renegotiated_funding_locked(
			self.funding.channel_parameters.clone(),
			self.funding.current_holder_commitment_tx.clone(),
			self.funding.prev_holder_commitment_tx.clone(),
		);

		// It's possible that no commitment updates happened during the lifecycle of the pending
		// splice's `FundingScope` that was promoted. If so, our `prev_holder_htlc_data` is
		// now irrelevant, since there's no valid previous commitment that exists for the current
		// funding transaction that could be broadcast.
		if self.funding.prev_holder_commitment_tx.is_none() {
			self.prev_holder_htlc_data.take();
		}

		let no_further_updates_allowed = self.no_further_updates_allowed();

		// The swap above places the previous `FundingScope` into `pending_funding`.
		for funding in self.pending_funding.drain(..) {
			let funding_txid = funding.funding_txid();
			self.outputs_to_watch.remove(&funding_txid);
			if no_further_updates_allowed && funding_txid != prev_funding_txid {
				self.pending_events.push(Event::DiscardFunding {
					channel_id: self.channel_id,
					funding_info: crate::events::FundingInfo::OutPoint {
						outpoint: funding.funding_outpoint(),
					},
				});
			}
		}
		if let Some((alternative_funding_txid, _)) = self.alternative_funding_confirmed.take() {
			// In exceedingly rare cases, it's possible there was a reorg that caused a potential funding to
			// be locked in that this `ChannelMonitor` has not yet seen. Thus, we avoid a runtime assertion
			// and only assert in debug mode.
			debug_assert_eq!(alternative_funding_txid, new_funding_txid);
		}

		Ok(())
	}

	#[rustfmt::skip]
	fn update_monitor<B: BroadcasterInterface, F: FeeEstimator, L: Logger>(
		&mut self, updates: &ChannelMonitorUpdate, broadcaster: &B, fee_estimator: &F, logger: &WithContext<L>
	) -> Result<(), ()> {
		if self.latest_update_id == LEGACY_CLOSED_CHANNEL_UPDATE_ID && updates.update_id == LEGACY_CLOSED_CHANNEL_UPDATE_ID {
			log_info!(logger, "Applying pre-0.1 post-force-closed update to monitor {} with {} change(s).",
				log_funding_info!(self), updates.updates.len());
		} else if updates.update_id == LEGACY_CLOSED_CHANNEL_UPDATE_ID {
			log_info!(logger, "Applying pre-0.1 force close update to monitor {} with {} change(s).",
				log_funding_info!(self), updates.updates.len());
		} else {
			log_info!(logger, "Applying update, bringing update_id from {} to {} with {} change(s).",
				self.latest_update_id, updates.update_id, updates.updates.len());
		}

		// ChannelMonitor updates may be applied after force close if we receive a preimage for a
		// broadcasted commitment transaction HTLC output that we'd like to claim on-chain. If this
		// is the case, we no longer have guaranteed access to the monitor's update ID, so we use a
		// sentinel value instead.
		//
		// The `ChannelManager` may also queue redundant `ChannelForceClosed` updates if it still
		// thinks the channel needs to have its commitment transaction broadcast, so we'll allow
		// them as well.
		if updates.update_id == LEGACY_CLOSED_CHANNEL_UPDATE_ID || self.lockdown_from_offchain {
			assert_eq!(updates.updates.len(), 1);
			match updates.updates[0] {
				ChannelMonitorUpdateStep::ReleasePaymentComplete { .. } => {},
				ChannelMonitorUpdateStep::ChannelForceClosed { .. } => {},
				// We should have already seen a `ChannelForceClosed` update if we're trying to
				// provide a preimage at this point.
				ChannelMonitorUpdateStep::PaymentPreimage { .. } =>
					debug_assert!(self.lockdown_from_offchain),
				_ => {
					log_error!(logger, "Attempted to apply post-force-close ChannelMonitorUpdate of type {}", updates.updates[0].variant_name());
					panic!("Attempted to apply post-force-close ChannelMonitorUpdate that wasn't providing a payment preimage");
				},
			}
		}
		if updates.update_id != LEGACY_CLOSED_CHANNEL_UPDATE_ID {
			if self.latest_update_id + 1 != updates.update_id {
				panic!("Attempted to apply ChannelMonitorUpdates out of order, check the update_id before passing an update to update_monitor!");
			}
		}
		let mut ret = Ok(());
		let bounded_fee_estimator = LowerBoundedFeeEstimator::new(fee_estimator);
		for update in updates.updates.iter() {
			match update {
				ChannelMonitorUpdateStep::LatestHolderCommitmentTXInfo { commitment_tx, htlc_outputs, claimed_htlcs, nondust_htlc_sources } => {
					log_trace!(logger, "Updating ChannelMonitor with latest holder commitment transaction info");
					if self.lockdown_from_offchain { panic!(); }
					if let Err(e) = self.provide_latest_holder_commitment_tx(
						commitment_tx.clone(), htlc_outputs, &claimed_htlcs,
						nondust_htlc_sources.clone()
					) {
						log_error!(logger, "Failed updating latest holder commitment transaction info: {}", e);
						ret = Err(());
					}
				}
				ChannelMonitorUpdateStep::LatestHolderCommitment {
					commitment_txs, htlc_data, claimed_htlcs,
				} => {
					log_trace!(logger, "Updating ChannelMonitor with {} latest holder commitment(s)", commitment_txs.len());
					assert!(!self.lockdown_from_offchain);
					if let Err(e) = self.update_holder_commitment_data(
						commitment_txs.clone(), htlc_data.clone(), claimed_htlcs,
					) {
						log_error!(logger, "Failed updating latest holder commitment state: {}", e);
						ret = Err(());
					}
				},
				// Soon we will drop the `LatestCounterpartyCommitmentTXInfo` variant in favor of `LatestCounterpartyCommitment`.
				// For now we just add the code to handle the new updates.
				// Next step: in channel, switch channel monitor updates to use the `LatestCounterpartyCommitment` variant.
				ChannelMonitorUpdateStep::LatestCounterpartyCommitmentTXInfo { commitment_txid, htlc_outputs, commitment_number, their_per_commitment_point, .. } => {
					log_trace!(logger, "Updating ChannelMonitor with latest counterparty commitment transaction info");
					if self.pending_funding.is_empty() {
						self.provide_latest_counterparty_commitment_tx(*commitment_txid, htlc_outputs.clone(), *commitment_number, *their_per_commitment_point)
					} else {
						log_error!(logger, "Received unexpected non-splice counterparty commitment monitor update");
						ret = Err(());
					}
				},
				ChannelMonitorUpdateStep::LatestCounterpartyCommitment {
					commitment_txs, htlc_data,
				} => {
					log_trace!(logger, "Updating ChannelMonitor with {} latest counterparty commitments", commitment_txs.len());
					if let Err(e) = self.update_counterparty_commitment_data(commitment_txs, htlc_data) {
						log_error!(logger, "Failed updating latest counterparty commitment state: {}", e);
						ret = Err(());
					}
				},
				ChannelMonitorUpdateStep::PaymentPreimage { payment_preimage, payment_info } => {
					log_trace!(logger, "Updating ChannelMonitor with payment preimage");
					self.provide_payment_preimage(&PaymentHash(Sha256::hash(&payment_preimage.0[..]).to_byte_array()), &payment_preimage, payment_info, broadcaster, &bounded_fee_estimator, logger)
				},
				ChannelMonitorUpdateStep::CommitmentSecret { idx, secret } => {
					log_trace!(logger, "Updating ChannelMonitor with commitment secret");
					if let Err(e) = self.provide_secret(*idx, *secret) {
						debug_assert!(false, "Latest counterparty commitment secret was invalid");
						log_error!(logger, "Providing latest counterparty commitment secret failed/was refused:");
						log_error!(logger, "    {}", e);
						ret = Err(());
					}
				},
				ChannelMonitorUpdateStep::RenegotiatedFunding {
					channel_parameters, holder_commitment_tx, counterparty_commitment_tx,
				} => {
					log_trace!(logger, "Updating ChannelMonitor with alternative holder and counterparty commitment transactions for funding txid {}",
						channel_parameters.funding_outpoint.unwrap().txid);
					if let Err(_) = self.renegotiated_funding(
						logger, channel_parameters, holder_commitment_tx, counterparty_commitment_tx,
					) {
						ret = Err(());
					}
				},
				ChannelMonitorUpdateStep::RenegotiatedFundingLocked { funding_txid } => {
					log_trace!(logger, "Updating ChannelMonitor with locked renegotiated funding txid {}", funding_txid);
					if let Err(_) = self.promote_funding(*funding_txid) {
						log_error!(logger, "Unknown funding with txid {} became locked", funding_txid);
						ret = Err(());
					}
				},
				ChannelMonitorUpdateStep::ChannelForceClosed { should_broadcast } => {
					log_trace!(logger, "Updating ChannelMonitor: channel force closed, should broadcast: {}", should_broadcast);
					self.lockdown_from_offchain = true;
					if *should_broadcast {
						// There's no need to broadcast our commitment transaction if we've seen one
						// confirmed (even with 1 confirmation) as it'll be rejected as
						// duplicate/conflicting.
						let detected_funding_spend = self.funding_spend_confirmed.is_some() ||
							self.onchain_events_awaiting_threshold_conf.iter().any(
								|event| matches!(event.event, OnchainEvent::FundingSpendConfirmation { .. }));
						if detected_funding_spend {
							log_trace!(logger, "Avoiding commitment broadcast, already detected confirmed spend onchain");
							continue;
						}
						self.queue_latest_holder_commitment_txn_for_broadcast(broadcaster, &bounded_fee_estimator, logger, true);
					} else if !self.holder_tx_signed {
						log_error!(logger, "WARNING: You have a potentially-unsafe holder commitment transaction available to broadcast");
						log_error!(logger, "    in channel monitor!");
						log_error!(logger, "    Read the docs for ChannelMonitor::broadcast_latest_holder_commitment_txn to take manual action!");
					} else {
						// If we generated a MonitorEvent::HolderForceClosed, the ChannelManager
						// will still give us a ChannelForceClosed event with !should_broadcast, but we
						// shouldn't print the scary warning above.
						log_info!(logger, "Channel off-chain state closed after we broadcasted our latest commitment transaction.");
					}
				},
				ChannelMonitorUpdateStep::ShutdownScript { scriptpubkey } => {
					log_trace!(logger, "Updating ChannelMonitor with shutdown script");
					if let Some(shutdown_script) = self.shutdown_script.replace(scriptpubkey.clone()) {
						panic!("Attempted to replace shutdown script {} with {}", shutdown_script, scriptpubkey);
					}
				},
				ChannelMonitorUpdateStep::ReleasePaymentComplete { htlc } => {
					log_trace!(logger, "HTLC {htlc:?} permanently and fully resolved");
					self.htlcs_resolved_to_user.insert(*htlc);
				},
			}
		}

		#[cfg(debug_assertions)] {
			self.counterparty_commitment_txs_from_update(updates);
		}

		self.latest_update_id = updates.update_id;

		// Refuse updates after we've detected a spend onchain (or if the channel was otherwise
		// closed), but only if the update isn't the kind of update we expect to see after channel
		// closure.
		let mut is_pre_close_update = false;
		for update in updates.updates.iter() {
			match update {
				ChannelMonitorUpdateStep::LatestHolderCommitmentTXInfo { .. }
					|ChannelMonitorUpdateStep::LatestHolderCommitment { .. }
					|ChannelMonitorUpdateStep::LatestCounterpartyCommitmentTXInfo { .. }
					|ChannelMonitorUpdateStep::LatestCounterpartyCommitment { .. }
					|ChannelMonitorUpdateStep::ShutdownScript { .. }
					|ChannelMonitorUpdateStep::CommitmentSecret { .. }
					|ChannelMonitorUpdateStep::RenegotiatedFunding { .. }
					|ChannelMonitorUpdateStep::RenegotiatedFundingLocked { .. } =>
						is_pre_close_update = true,
				// After a channel is closed, we don't communicate with our peer about it, so the
				// only things we will update is getting a new preimage (from a different channel),
				// being told that the channel is closed, or being told a payment which was
				// resolved on-chain has had its resolution communicated to the user. All other
				// updates are generated while talking to our peer.
				ChannelMonitorUpdateStep::PaymentPreimage { .. } => {},
				ChannelMonitorUpdateStep::ChannelForceClosed { .. } => {},
				ChannelMonitorUpdateStep::ReleasePaymentComplete { .. } => {},
			}
		}

		if ret.is_ok() && self.no_further_updates_allowed() && is_pre_close_update {
			log_error!(logger, "Refusing Channel Monitor Update as counterparty attempted to update commitment after funding was spent");
			Err(())
		} else { ret }
	}

	/// Returns true if the channel has been closed (i.e. no further updates are allowed) and no
	/// commitment state updates ever happened.
	fn is_closed_without_updates(&self) -> bool {
		let mut commitment_not_advanced =
			self.current_counterparty_commitment_number == INITIAL_COMMITMENT_NUMBER;
		commitment_not_advanced &=
			self.current_holder_commitment_number == INITIAL_COMMITMENT_NUMBER;
		(self.holder_tx_signed || self.lockdown_from_offchain) && commitment_not_advanced
	}

	fn no_further_updates_allowed(&self) -> bool {
		self.funding_spend_seen || self.lockdown_from_offchain || self.holder_tx_signed
	}

	fn get_latest_update_id(&self) -> u64 {
		self.latest_update_id
	}

	/// Returns the outpoint we are currently monitoring the chain for spends. This will change for
	/// every splice that has reached its intended confirmation depth.
	#[rustfmt::skip]
	fn get_funding_txo(&self) -> OutPoint {
		self.funding.channel_parameters.funding_outpoint
			.expect("Funding outpoint must be set for active monitor")
	}

	/// Returns the P2WSH script we are currently monitoring the chain for spends. This will change
	/// for every splice that has reached its intended confirmation depth.
	fn get_funding_script(&self) -> ScriptBuf {
		self.funding.channel_parameters.make_funding_redeemscript().to_p2wsh()
	}

	pub fn channel_id(&self) -> ChannelId {
		self.channel_id
	}

	fn get_outputs_to_watch(&self) -> &HashMap<Txid, Vec<(u32, ScriptBuf)>> {
		// If we've detected a counterparty commitment tx on chain, we must include it in the set
		// of outputs to watch for spends of, otherwise we're likely to lose user funds. Because
		// its trivial to do, double-check that here.
		for txid in self.counterparty_commitment_txn_on_chain.keys() {
			self.outputs_to_watch.get(txid).expect("Counterparty commitment txn which have been broadcast should have outputs registered");
		}
		&self.outputs_to_watch
	}

	fn get_and_clear_pending_monitor_events(&mut self) -> Vec<MonitorEvent> {
		let mut ret = Vec::new();
		mem::swap(&mut ret, &mut self.pending_monitor_events);
		ret
	}

	/// Gets the set of events that are repeated regularly (e.g. those which RBF bump
	/// transactions). We're okay if we lose these on restart as they'll be regenerated for us at
	/// some regular interval via [`ChannelMonitor::rebroadcast_pending_claims`].
	#[rustfmt::skip]
	pub(super) fn get_repeated_events(&mut self) -> Vec<Event> {
		let pending_claim_events = self.onchain_tx_handler.get_and_clear_pending_claim_events();
		let mut ret = Vec::with_capacity(pending_claim_events.len());
		for (claim_id, claim_event) in pending_claim_events {
			match claim_event {
				ClaimEvent::BumpCommitment {
					package_target_feerate_sat_per_1000_weight, commitment_tx,
					commitment_tx_fee_satoshis, pending_nondust_htlcs, anchor_output_idx,
					channel_parameters,
				} => {
					let channel_id = self.channel_id;
					let counterparty_node_id = self.counterparty_node_id;
					let commitment_txid = commitment_tx.compute_txid();
					ret.push(Event::BumpTransaction(BumpTransactionEvent::ChannelClose {
						channel_id,
						counterparty_node_id,
						claim_id,
						package_target_feerate_sat_per_1000_weight,
						anchor_descriptor: AnchorDescriptor {
							channel_derivation_parameters: ChannelDerivationParameters {
								keys_id: self.channel_keys_id,
								value_satoshis: channel_parameters.channel_value_satoshis,
								transaction_parameters: channel_parameters,
							},
							outpoint: BitcoinOutPoint {
								txid: commitment_txid,
								vout: anchor_output_idx,
							},
							value: commitment_tx.output[anchor_output_idx as usize].value,
						},
						pending_htlcs: pending_nondust_htlcs,
						commitment_tx,
						commitment_tx_fee_satoshis,
					}));
				},
				ClaimEvent::BumpHTLC {
					target_feerate_sat_per_1000_weight, htlcs, tx_lock_time,
				} => {
					let channel_id = self.channel_id;
					let counterparty_node_id = self.counterparty_node_id;
					ret.push(Event::BumpTransaction(BumpTransactionEvent::HTLCResolution {
						channel_id,
						counterparty_node_id,
						claim_id,
						target_feerate_sat_per_1000_weight,
						htlc_descriptors: htlcs,
						tx_lock_time,
					}));
				}
			}
		}
		ret
	}

	fn initial_counterparty_commitment_tx(&mut self) -> Option<CommitmentTransaction> {
		self.initial_counterparty_commitment_tx.clone().or_else(|| {
			// This provides forward compatibility; an old monitor will not contain the full
			// transaction; only enough information to rebuild it
			self.initial_counterparty_commitment_info.map(
				|(
					their_per_commitment_point,
					feerate_per_kw,
					to_broadcaster_value,
					to_countersignatory_value,
				)| {
					let nondust_htlcs = vec![];
					// Since we're expected to only reach here during the initial persistence of a
					// monitor (i.e., via [`Persist::persist_new_channel`]), we expect to only have
					// one `FundingScope` present.
					debug_assert!(self.pending_funding.is_empty());
					let channel_parameters = &self.funding.channel_parameters;

					let commitment_tx = self.build_counterparty_commitment_tx(
						channel_parameters,
						INITIAL_COMMITMENT_NUMBER,
						&their_per_commitment_point,
						to_broadcaster_value,
						to_countersignatory_value,
						feerate_per_kw,
						nondust_htlcs,
					);
					// Take the opportunity to populate this recently introduced field
					self.initial_counterparty_commitment_tx = Some(commitment_tx.clone());
					commitment_tx
				},
			)
		})
	}

	#[rustfmt::skip]
	fn build_counterparty_commitment_tx(
		&self, channel_parameters: &ChannelTransactionParameters, commitment_number: u64,
		their_per_commitment_point: &PublicKey, to_broadcaster_value: u64,
		to_countersignatory_value: u64, feerate_per_kw: u32,
		nondust_htlcs: Vec<HTLCOutputInCommitment>
	) -> CommitmentTransaction {
		let channel_parameters = &channel_parameters.as_counterparty_broadcastable();
		CommitmentTransaction::new(commitment_number, their_per_commitment_point,
			to_broadcaster_value, to_countersignatory_value, feerate_per_kw, nondust_htlcs, channel_parameters, &self.onchain_tx_handler.secp_ctx)
	}

	#[rustfmt::skip]
	fn counterparty_commitment_txs_from_update(&self, update: &ChannelMonitorUpdate) -> Vec<CommitmentTransaction> {
		update.updates.iter().filter_map(|update| {
			// Soon we will drop the first branch here in favor of the second.
			// In preparation, we just add the second branch without deleting the first.
			// Next step: in channel, switch channel monitor updates to use the `LatestCounterpartyCommitment` variant.
			match update {
				&ChannelMonitorUpdateStep::LatestCounterpartyCommitmentTXInfo { commitment_txid,
					ref htlc_outputs, commitment_number, their_per_commitment_point,
					feerate_per_kw: Some(feerate_per_kw),
					to_broadcaster_value_sat: Some(to_broadcaster_value),
					to_countersignatory_value_sat: Some(to_countersignatory_value) } => {

					let nondust_htlcs = htlc_outputs.iter().filter_map(|(htlc, _)| {
						htlc.transaction_output_index.map(|_| htlc).cloned()
					}).collect::<Vec<_>>();

					// This monitor update variant is only applicable while there's a single
					// `FundingScope` active, otherwise we expect to see
					// `LatestCounterpartyCommitment` instead.
					debug_assert!(self.pending_funding.is_empty());
					let channel_parameters = &self.funding.channel_parameters;
					let commitment_tx = self.build_counterparty_commitment_tx(
						channel_parameters,
						commitment_number,
						&their_per_commitment_point,
						to_broadcaster_value,
						to_countersignatory_value,
						feerate_per_kw,
						nondust_htlcs,
					);

					debug_assert_eq!(commitment_tx.trust().txid(), commitment_txid);

					Some(vec![commitment_tx])
				},
				&ChannelMonitorUpdateStep::LatestCounterpartyCommitment { ref commitment_txs, .. } => {
					Some(commitment_txs.clone())
				},
				&ChannelMonitorUpdateStep::RenegotiatedFunding { ref counterparty_commitment_tx, .. } => {
					Some(vec![counterparty_commitment_tx.clone()])
				},
				_ => None,
			}
		}).flatten().collect()
	}

	#[rustfmt::skip]
	fn sign_to_local_justice_tx(
		&self, mut justice_tx: Transaction, input_idx: usize, value: u64, commitment_number: u64
	) -> Result<Transaction, ()> {
		let secret = self.get_secret(commitment_number).ok_or(())?;
		let per_commitment_key = SecretKey::from_slice(&secret).map_err(|_| ())?;
		let their_per_commitment_point = PublicKey::from_secret_key(
			&self.onchain_tx_handler.secp_ctx, &per_commitment_key);

		let revocation_pubkey = RevocationKey::from_basepoint(&self.onchain_tx_handler.secp_ctx,
			&self.holder_revocation_basepoint, &their_per_commitment_point);
		let delayed_key = DelayedPaymentKey::from_basepoint(&self.onchain_tx_handler.secp_ctx,
			&self.counterparty_commitment_params.counterparty_delayed_payment_base_key, &their_per_commitment_point);
		let revokeable_redeemscript = chan_utils::get_revokeable_redeemscript(&revocation_pubkey,
			self.counterparty_commitment_params.on_counterparty_tx_csv, &delayed_key);

		let commitment_txid = &justice_tx.input[input_idx].previous_output.txid;
		// Since there may be multiple counterparty commitment transactions for the same commitment
		// number due to splicing, we have to locate the matching `FundingScope::channel_parameters`
		// to provide the signer. Since this is intended to be called during
		// `Persist::update_persisted_channel`, the monitor should have already had the update
		// applied.
		let channel_parameters = core::iter::once(&self.funding)
			.chain(&self.pending_funding)
			.find(|funding| funding.counterparty_claimable_outpoints.contains_key(commitment_txid))
			.map(|funding| &funding.channel_parameters)
			.ok_or(())?;
		let sig = self.onchain_tx_handler.signer.sign_justice_revoked_output(
			&channel_parameters, &justice_tx, input_idx, value, &per_commitment_key,
			&self.onchain_tx_handler.secp_ctx,
		)?;
		justice_tx.input[input_idx].witness.push_ecdsa_signature(&BitcoinSignature::sighash_all(sig));
		justice_tx.input[input_idx].witness.push(&[1u8]);
		justice_tx.input[input_idx].witness.push(revokeable_redeemscript.as_bytes());
		Ok(justice_tx)
	}

	/// Can only fail if idx is < get_min_seen_secret
	fn get_secret(&self, idx: u64) -> Option<[u8; 32]> {
		self.commitment_secrets.get_secret(idx)
	}

	fn get_min_seen_secret(&self) -> u64 {
		self.commitment_secrets.get_min_seen_secret()
	}

	fn get_cur_counterparty_commitment_number(&self) -> u64 {
		self.current_counterparty_commitment_number
	}

	fn get_cur_holder_commitment_number(&self) -> u64 {
		self.current_holder_commitment_number
	}

	/// Attempts to claim a counterparty commitment transaction's outputs using the revocation key and
	/// data in counterparty_claimable_outpoints. Will directly claim any HTLC outputs which expire at a
	/// height > height + CLTV_SHARED_CLAIM_BUFFER. In any case, will install monitoring for
	/// HTLC-Success/HTLC-Timeout transactions.
	///
	/// Returns packages to claim the revoked output(s) and general information about the output that
	/// is to the counterparty in the commitment transaction.
	#[rustfmt::skip]
	fn check_spend_counterparty_transaction<L: Logger>(&mut self, commitment_txid: Txid, commitment_tx: &Transaction, height: u32, block_hash: &BlockHash, logger: &L)
		-> (Vec<PackageTemplate>, CommitmentTxCounterpartyOutputInfo)
	{
		// Most secp and related errors trying to create keys means we have no hope of constructing
		// a spend transaction...so we return no transactions to broadcast
		let mut claimable_outpoints = Vec::new();
		let mut to_counterparty_output_info = None;

		let funding_spent = get_confirmed_funding_scope!(self);
		let per_commitment_option = funding_spent.counterparty_claimable_outpoints.get(&commitment_txid);

		macro_rules! ignore_error {
			( $thing : expr ) => {
				match $thing {
					Ok(a) => a,
					Err(_) => return (claimable_outpoints, to_counterparty_output_info)
				}
			};
		}

		let funding_txid_spent = commitment_tx.input[0].previous_output.txid;
		let commitment_number = 0xffffffffffff - ((((commitment_tx.input[0].sequence.0 as u64 & 0xffffff) << 3*8) | (commitment_tx.lock_time.to_consensus_u32() as u64 & 0xffffff)) ^ self.commitment_transaction_number_obscure_factor);
		if commitment_number >= self.get_min_seen_secret() {
			assert_eq!(funding_spent.funding_txid(), funding_txid_spent);

			let secret = self.get_secret(commitment_number).unwrap();
			let per_commitment_key = ignore_error!(SecretKey::from_slice(&secret));
			let per_commitment_point = PublicKey::from_secret_key(&self.onchain_tx_handler.secp_ctx, &per_commitment_key);
			let revocation_pubkey = RevocationKey::from_basepoint(&self.onchain_tx_handler.secp_ctx,  &self.holder_revocation_basepoint, &per_commitment_point,);
			let delayed_key = DelayedPaymentKey::from_basepoint(&self.onchain_tx_handler.secp_ctx, &self.counterparty_commitment_params.counterparty_delayed_payment_base_key, &PublicKey::from_secret_key(&self.onchain_tx_handler.secp_ctx, &per_commitment_key));

			let revokeable_redeemscript = chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.counterparty_commitment_params.on_counterparty_tx_csv, &delayed_key);
			let revokeable_p2wsh = revokeable_redeemscript.to_p2wsh();

			// First, process non-htlc outputs (to_holder & to_counterparty)
			for (idx, outp) in commitment_tx.output.iter().enumerate() {
				if outp.script_pubkey == revokeable_p2wsh {
					let revk_outp = RevokedOutput::build(
						per_commitment_point, per_commitment_key, outp.value,
						funding_spent.channel_parameters.clone(), height,
					);
					let justice_package = PackageTemplate::build_package(
						commitment_txid, idx as u32,
						PackageSolvingData::RevokedOutput(revk_outp),
						height + self.counterparty_commitment_params.on_counterparty_tx_csv as u32,
					);
					claimable_outpoints.push(justice_package);
					to_counterparty_output_info =
						Some((idx.try_into().expect("Txn can't have more than 2^32 outputs"), outp.value));
				}
			}

			// Then, try to find revoked htlc outputs
			if let Some(per_commitment_claimable_data) = per_commitment_option {
				for (htlc, _) in per_commitment_claimable_data {
					if let Some(transaction_output_index) = htlc.transaction_output_index {
						if transaction_output_index as usize >= commitment_tx.output.len() ||
								commitment_tx.output[transaction_output_index as usize].value != htlc.to_bitcoin_amount() {
							// per_commitment_data is corrupt or our commitment signing key leaked!
							return (claimable_outpoints, to_counterparty_output_info);
						}
						let revk_htlc_outp = RevokedHTLCOutput::build(
							per_commitment_point, per_commitment_key, htlc.clone(),
							funding_spent.channel_parameters.clone(), height,
						);
						let counterparty_spendable_height = if htlc.offered {
							htlc.cltv_expiry
						} else {
							height
						};
						let justice_package = PackageTemplate::build_package(
							commitment_txid,
							transaction_output_index,
							PackageSolvingData::RevokedHTLCOutput(revk_htlc_outp),
							counterparty_spendable_height,
						);
						claimable_outpoints.push(justice_package);
					}
				}
			}

			// Last, track onchain revoked commitment transaction and fail backward outgoing HTLCs as payment path is broken
			if !claimable_outpoints.is_empty() || per_commitment_option.is_some() { // ie we're confident this is actually ours
				// We're definitely a counterparty commitment transaction!
				log_error!(logger, "Got broadcast of revoked counterparty commitment transaction, going to generate general spend tx with {} inputs", claimable_outpoints.len());
				self.counterparty_commitment_txn_on_chain.insert(commitment_txid, commitment_number);

				if let Some(per_commitment_claimable_data) = per_commitment_option {
					fail_unbroadcast_htlcs!(self, "revoked_counterparty", commitment_txid, commitment_tx, height,
						block_hash, per_commitment_claimable_data.iter().map(|(htlc, htlc_source)|
							(htlc, htlc_source.as_ref().map(|htlc_source| htlc_source.as_ref()))
						), logger);
				} else {
					// Our fuzzers aren't constrained by pesky things like valid signatures, so can
					// spend our funding output with a transaction which doesn't match our past
					// commitment transactions. Thus, we can only debug-assert here when not
					// fuzzing.
					debug_assert!(cfg!(fuzzing), "We should have per-commitment option for any recognized old commitment txn");
					fail_unbroadcast_htlcs!(self, "revoked counterparty", commitment_txid, commitment_tx, height,
						block_hash, [].iter().map(|reference| *reference), logger);
				}
			}
		} else if let Some(per_commitment_claimable_data) = per_commitment_option {
			assert_eq!(funding_spent.funding_txid(), funding_txid_spent);

			// While this isn't useful yet, there is a potential race where if a counterparty
			// revokes a state at the same time as the commitment transaction for that state is
			// confirmed, and the watchtower receives the block before the user, the user could
			// upload a new ChannelMonitor with the revocation secret but the watchtower has
			// already processed the block, resulting in the counterparty_commitment_txn_on_chain entry
			// not being generated by the above conditional. Thus, to be safe, we go ahead and
			// insert it here.
			self.counterparty_commitment_txn_on_chain.insert(commitment_txid, commitment_number);

			log_info!(logger, "Got broadcast of non-revoked counterparty commitment transaction {}", commitment_txid);
			fail_unbroadcast_htlcs!(self, "counterparty", commitment_txid, commitment_tx, height, block_hash,
				per_commitment_claimable_data.iter().map(|(htlc, htlc_source)|
					(htlc, htlc_source.as_ref().map(|htlc_source| htlc_source.as_ref()))
				), logger);
			let (htlc_claim_reqs, counterparty_output_info) =
				self.get_counterparty_output_claim_info(funding_spent, commitment_number, commitment_txid, commitment_tx, per_commitment_claimable_data, Some(height));
			to_counterparty_output_info = counterparty_output_info;
			for req in htlc_claim_reqs {
				claimable_outpoints.push(req);
			}
		}

		(claimable_outpoints, to_counterparty_output_info)
	}

	fn get_point_for_commitment_number(&self, commitment_number: u64) -> Option<PublicKey> {
		let per_commitment_points = &self.their_cur_per_commitment_points?;

		// If the counterparty commitment tx is the latest valid state, use their latest
		// per-commitment point
		if per_commitment_points.0 == commitment_number {
			Some(per_commitment_points.1)
		} else if let Some(point) = per_commitment_points.2.as_ref() {
			// If counterparty commitment tx is the state previous to the latest valid state, use
			// their previous per-commitment point (non-atomicity of revocation means it's valid for
			// them to temporarily have two valid commitment txns from our viewpoint)
			if per_commitment_points.0 == commitment_number + 1 {
				Some(*point)
			} else {
				None
			}
		} else {
			None
		}
	}

	fn get_counterparty_output_claims_for_preimage(
		&self, preimage: PaymentPreimage, funding_spent: &FundingScope, commitment_number: u64,
		commitment_txid: Txid,
		per_commitment_option: Option<&Vec<(HTLCOutputInCommitment, Option<Box<HTLCSource>>)>>,
		confirmation_height: Option<u32>,
	) -> Vec<PackageTemplate> {
		let per_commitment_claimable_data = match per_commitment_option {
			Some(outputs) => outputs,
			None => return Vec::new(),
		};
		let per_commitment_point = match self.get_point_for_commitment_number(commitment_number) {
			Some(point) => point,
			None => return Vec::new(),
		};

		let matching_payment_hash = PaymentHash::from(preimage);
		per_commitment_claimable_data
			.iter()
			.filter_map(|(htlc, _)| {
				if let Some(transaction_output_index) = htlc.transaction_output_index {
					if htlc.offered && htlc.payment_hash == matching_payment_hash {
						let htlc_data = PackageSolvingData::CounterpartyOfferedHTLCOutput(
							CounterpartyOfferedHTLCOutput::build(
								per_commitment_point,
								preimage,
								htlc.clone(),
								funding_spent.channel_parameters.clone(),
								confirmation_height,
							),
						);
						Some(PackageTemplate::build_package(
							commitment_txid,
							transaction_output_index,
							htlc_data,
							htlc.cltv_expiry,
						))
					} else {
						None
					}
				} else {
					None
				}
			})
			.collect()
	}

	/// Returns the HTLC claim package templates and the counterparty output info
	fn get_counterparty_output_claim_info(
		&self, funding_spent: &FundingScope, commitment_number: u64, commitment_txid: Txid,
		tx: &Transaction,
		per_commitment_claimable_data: &[(HTLCOutputInCommitment, Option<Box<HTLCSource>>)],
		confirmation_height: Option<u32>,
	) -> (Vec<PackageTemplate>, CommitmentTxCounterpartyOutputInfo) {
		let mut claimable_outpoints = Vec::new();
		let mut to_counterparty_output_info: CommitmentTxCounterpartyOutputInfo = None;

		let per_commitment_point = match self.get_point_for_commitment_number(commitment_number) {
			Some(point) => point,
			None => return (claimable_outpoints, to_counterparty_output_info),
		};

		let revocation_pubkey = RevocationKey::from_basepoint(
			&self.onchain_tx_handler.secp_ctx,
			&self.holder_revocation_basepoint,
			&per_commitment_point,
		);
		let delayed_key = DelayedPaymentKey::from_basepoint(
			&self.onchain_tx_handler.secp_ctx,
			&self.counterparty_commitment_params.counterparty_delayed_payment_base_key,
			&per_commitment_point,
		);
		let revokeable_p2wsh = chan_utils::get_revokeable_redeemscript(
			&revocation_pubkey,
			self.counterparty_commitment_params.on_counterparty_tx_csv,
			&delayed_key,
		)
		.to_p2wsh();
		for (idx, outp) in tx.output.iter().enumerate() {
			if outp.script_pubkey == revokeable_p2wsh {
				to_counterparty_output_info =
					Some((idx.try_into().expect("Can't have > 2^32 outputs"), outp.value));
			}
		}

		for &(ref htlc, _) in per_commitment_claimable_data.iter() {
			if let Some(transaction_output_index) = htlc.transaction_output_index {
				if transaction_output_index as usize >= tx.output.len()
					|| tx.output[transaction_output_index as usize].value
						!= htlc.to_bitcoin_amount()
				{
					// per_commitment_data is corrupt or our commitment signing key leaked!
					return (claimable_outpoints, to_counterparty_output_info);
				}
				let preimage = if htlc.offered {
					if let Some((p, _)) = self.payment_preimages.get(&htlc.payment_hash) {
						Some(*p)
					} else {
						None
					}
				} else {
					None
				};
				if preimage.is_some() || !htlc.offered {
					let counterparty_htlc_outp = if htlc.offered {
						PackageSolvingData::CounterpartyOfferedHTLCOutput(
							CounterpartyOfferedHTLCOutput::build(
								per_commitment_point,
								preimage.unwrap(),
								htlc.clone(),
								funding_spent.channel_parameters.clone(),
								confirmation_height,
							),
						)
					} else {
						PackageSolvingData::CounterpartyReceivedHTLCOutput(
							CounterpartyReceivedHTLCOutput::build(
								per_commitment_point,
								htlc.clone(),
								funding_spent.channel_parameters.clone(),
								confirmation_height,
							),
						)
					};
					let counterparty_package = PackageTemplate::build_package(
						commitment_txid,
						transaction_output_index,
						counterparty_htlc_outp,
						htlc.cltv_expiry,
					);
					claimable_outpoints.push(counterparty_package);
				}
			}
		}

		(claimable_outpoints, to_counterparty_output_info)
	}

	/// Attempts to claim a counterparty HTLC-Success/HTLC-Timeout's outputs using the revocation key
	#[rustfmt::skip]
	fn check_spend_counterparty_htlc<L: Logger>(
		&mut self, tx: &Transaction, commitment_number: u64, commitment_txid: &Txid, height: u32, logger: &L
	) -> (Vec<PackageTemplate>, Option<TransactionOutputs>) {
		let secret = if let Some(secret) = self.get_secret(commitment_number) { secret } else { return (Vec::new(), None); };
		let per_commitment_key = match SecretKey::from_slice(&secret) {
			Ok(key) => key,
			Err(_) => return (Vec::new(), None)
		};
		let per_commitment_point = PublicKey::from_secret_key(&self.onchain_tx_handler.secp_ctx, &per_commitment_key);

		let funding_spent = get_confirmed_funding_scope!(self);
		debug_assert!(funding_spent.counterparty_claimable_outpoints.contains_key(commitment_txid));

		let htlc_txid = tx.compute_txid();
		let mut claimable_outpoints = vec![];
		let mut outputs_to_watch = None;
		// Previously, we would only claim HTLCs from revoked HTLC transactions if they had 1 input
		// with a witness of 5 elements and 1 output. This wasn't enough for anchor outputs, as the
		// counterparty can now aggregate multiple HTLCs into a single transaction thanks to
		// `SIGHASH_SINGLE` remote signatures, leading us to not claim any HTLCs upon seeing a
		// confirmed revoked HTLC transaction (for more details, see
		// https://lists.linuxfoundation.org/pipermail/lightning-dev/2022-April/003561.html).
		//
		// We make sure we're not vulnerable to this case by checking all inputs of the transaction,
		// and claim those which spend the commitment transaction, have a witness of 5 elements, and
		// have a corresponding output at the same index within the transaction.
		for (idx, input) in tx.input.iter().enumerate() {
			if input.previous_output.txid == *commitment_txid && input.witness.len() == 5 && tx.output.get(idx).is_some() {
				log_error!(logger, "Got broadcast of revoked counterparty HTLC transaction, spending {}:{}", htlc_txid, idx);
				let revk_outp = RevokedOutput::build(
					per_commitment_point, per_commitment_key, tx.output[idx].value,
					self.funding.channel_parameters.clone(), height,
				);
				let justice_package = PackageTemplate::build_package(
					htlc_txid, idx as u32, PackageSolvingData::RevokedOutput(revk_outp),
					height + self.counterparty_commitment_params.on_counterparty_tx_csv as u32,
				);
				claimable_outpoints.push(justice_package);
				if outputs_to_watch.is_none() {
					outputs_to_watch = Some((htlc_txid, vec![]));
				}
				outputs_to_watch.as_mut().unwrap().1.push((idx as u32, tx.output[idx].clone()));
			}
		}
		(claimable_outpoints, outputs_to_watch)
	}

	#[rustfmt::skip]
	fn get_broadcasted_holder_htlc_descriptors(
		&self, funding: &FundingScope, holder_tx: &HolderCommitmentTransaction,
	) -> Vec<HTLCDescriptor> {
		let tx = holder_tx.trust();
		let mut htlcs = Vec::with_capacity(holder_tx.nondust_htlcs().len());
		debug_assert_eq!(holder_tx.nondust_htlcs().len(), holder_tx.counterparty_htlc_sigs.len());
		for (htlc, counterparty_sig) in holder_tx.nondust_htlcs().iter().zip(holder_tx.counterparty_htlc_sigs.iter()) {
			assert!(htlc.transaction_output_index.is_some(), "Expected transaction output index for non-dust HTLC");

			let preimage = if htlc.offered {
				None
			} else if let Some((preimage, _)) = self.payment_preimages.get(&htlc.payment_hash) {
				Some(*preimage)
			} else {
				// We can't build an HTLC-Success transaction without the preimage
				continue;
			};

			htlcs.push(HTLCDescriptor {
				channel_derivation_parameters: ChannelDerivationParameters {
					value_satoshis: funding.channel_parameters.channel_value_satoshis,
					keys_id: self.channel_keys_id,
					transaction_parameters: funding.channel_parameters.clone(),
				},
				commitment_txid: tx.txid(),
				per_commitment_number: tx.commitment_number(),
				per_commitment_point: tx.per_commitment_point(),
				feerate_per_kw: tx.negotiated_feerate_per_kw(),
				htlc: htlc.clone(),
				preimage,
				counterparty_sig: *counterparty_sig,
			});
		}

		htlcs
	}

	// Returns (1) `PackageTemplate`s that can be given to the OnchainTxHandler, so that the handler can
	// broadcast transactions claiming holder HTLC commitment outputs and (2) a holder revokable
	// script so we can detect whether a holder transaction has been seen on-chain.
	#[rustfmt::skip]
	fn get_broadcasted_holder_claims(
		&self, funding: &FundingScope, holder_tx: &HolderCommitmentTransaction, conf_height: u32,
	) -> (Vec<PackageTemplate>, Option<(ScriptBuf, PublicKey, RevocationKey)>) {
		let tx = holder_tx.trust();
		let keys = tx.keys();
		let redeem_script = chan_utils::get_revokeable_redeemscript(
			&keys.revocation_key, self.on_holder_tx_csv, &keys.broadcaster_delayed_payment_key,
		);
		let broadcasted_holder_revokable_script = Some((
			redeem_script.to_p2wsh(), holder_tx.per_commitment_point(), keys.revocation_key.clone(),
		));

		let claim_requests = self.get_broadcasted_holder_htlc_descriptors(funding, holder_tx).into_iter()
			.map(|htlc_descriptor| {
				let counterparty_spendable_height = if htlc_descriptor.htlc.offered {
					conf_height
				} else {
					htlc_descriptor.htlc.cltv_expiry
				};
				let transaction_output_index = htlc_descriptor.htlc.transaction_output_index
					.expect("Expected transaction output index for non-dust HTLC");
				PackageTemplate::build_package(
					tx.txid(), transaction_output_index,
					PackageSolvingData::HolderHTLCOutput(HolderHTLCOutput::build(htlc_descriptor, conf_height)),
					counterparty_spendable_height,
				)
			})
			.collect();

		(claim_requests, broadcasted_holder_revokable_script)
	}

	// Returns holder HTLC outputs to watch and react to in case of spending.
	#[rustfmt::skip]
	fn get_broadcasted_holder_watch_outputs(&self, holder_tx: &HolderCommitmentTransaction) -> Vec<(u32, TxOut)> {
		let mut watch_outputs = Vec::with_capacity(holder_tx.nondust_htlcs().len());
		let tx = holder_tx.trust();
		for htlc in holder_tx.nondust_htlcs() {
			if let Some(transaction_output_index) = htlc.transaction_output_index {
				watch_outputs.push((
					transaction_output_index,
					tx.built_transaction().transaction.output[transaction_output_index as usize].clone(),
				));
			} else {
				debug_assert!(false, "Expected transaction output index for non-dust HTLC");
			}
		}
		watch_outputs
	}

	/// Attempts to claim any claimable HTLCs in a commitment transaction which was not (yet)
	/// revoked using data in holder_claimable_outpoints.
	/// Should not be used if check_spend_revoked_transaction succeeds.
	/// Returns None unless the transaction is definitely one of our commitment transactions.
	fn check_spend_holder_transaction<L: Logger>(
		&mut self, commitment_txid: Txid, commitment_tx: &Transaction, height: u32,
		block_hash: &BlockHash, logger: &L,
	) -> Option<(Vec<PackageTemplate>, TransactionOutputs)> {
		let funding_spent = get_confirmed_funding_scope!(self);

		// HTLCs set may differ between last and previous holder commitment txn, in case of one them hitting chain, ensure we cancel all HTLCs backward
		let holder_commitment_tx = Some((&funding_spent.current_holder_commitment_tx, true))
			.filter(|(current_holder_commitment_tx, _)| {
				current_holder_commitment_tx.trust().txid() == commitment_txid
			})
			.or_else(|| {
				funding_spent
					.prev_holder_commitment_tx
					.as_ref()
					.map(|prev_holder_commitment_tx| (prev_holder_commitment_tx, false))
					.filter(|(prev_holder_commitment_tx, _)| {
						prev_holder_commitment_tx.trust().txid() == commitment_txid
					})
			});

		if let Some((holder_commitment_tx, current)) = holder_commitment_tx {
			let funding_txid_spent = commitment_tx.input[0].previous_output.txid;
			assert_eq!(funding_spent.funding_txid(), funding_txid_spent);

			let current_msg = if current { "latest holder" } else { "previous holder" };
			log_info!(logger, "Got broadcast of {current_msg} commitment tx {commitment_txid}, searching for available HTLCs to claim");

			let (claim_requests, broadcasted_holder_revokable_script) =
				self.get_broadcasted_holder_claims(funding_spent, holder_commitment_tx, height);
			self.broadcasted_holder_revokable_script = broadcasted_holder_revokable_script;
			let watch_outputs = self.get_broadcasted_holder_watch_outputs(holder_commitment_tx);

			if current {
				fail_unbroadcast_htlcs!(
					self,
					current_msg,
					commitment_txid,
					commitment_tx,
					height,
					block_hash,
					holder_commitment_htlcs!(self, CURRENT_WITH_SOURCES),
					logger
				);
			} else {
				fail_unbroadcast_htlcs!(
					self,
					current_msg,
					commitment_txid,
					commitment_tx,
					height,
					block_hash,
					holder_commitment_htlcs!(self, PREV_WITH_SOURCES).unwrap(),
					logger
				);
			}

			Some((claim_requests, (commitment_txid, watch_outputs)))
		} else {
			None
		}
	}

	/// Cancels any existing pending claims for a commitment that previously confirmed and has now
	/// been replaced by another.
	#[rustfmt::skip]
	pub fn cancel_prev_commitment_claims<L: Logger>(
		&mut self, logger: &L, confirmed_commitment_txid: &Txid
	) {
		for (counterparty_commitment_txid, _) in &self.counterparty_commitment_txn_on_chain {
			// Cancel any pending claims for counterparty commitments we've seen confirm.
			if counterparty_commitment_txid == confirmed_commitment_txid {
				continue;
			}
			// If we have generated claims for counterparty_commitment_txid earlier, we can rely on always
			// having claim related htlcs for counterparty_commitment_txid in counterparty_claimable_outpoints.
			for funding in core::iter::once(&self.funding).chain(self.pending_funding.iter()) {
				let mut found_claim = false;
				for (htlc, _) in funding.counterparty_claimable_outpoints.get(counterparty_commitment_txid).unwrap_or(&vec![]) {
					let mut outpoint = BitcoinOutPoint { txid: *counterparty_commitment_txid, vout: 0 };
					if let Some(vout) = htlc.transaction_output_index {
						outpoint.vout = vout;
						if self.onchain_tx_handler.abandon_claim(&outpoint) {
							found_claim = true;
						}
					}
				}
				if found_claim {
					log_trace!(logger, "Canceled claims for previously confirmed counterparty commitment with txid {counterparty_commitment_txid}");
				}
			}
		}
		// Cancel any pending claims for any holder commitments in case they had previously
		// confirmed or been signed (in which case we will start attempting to claim without
		// waiting for confirmation).
		for funding in core::iter::once(&self.funding).chain(self.pending_funding.iter()) {
			if funding.current_holder_commitment_tx.trust().txid() != *confirmed_commitment_txid {
				let mut found_claim = false;
				let txid = funding.current_holder_commitment_tx.trust().txid();
				let mut outpoint = BitcoinOutPoint { txid, vout: 0 };
				for htlc in funding.current_holder_commitment_tx.nondust_htlcs() {
					if let Some(vout) = htlc.transaction_output_index {
						outpoint.vout = vout;
						if self.onchain_tx_handler.abandon_claim(&outpoint) {
							found_claim = true;
						}
					} else {
						debug_assert!(false, "Expected transaction output index for non-dust HTLC");
					}
				}
				if found_claim {
					log_trace!(logger, "Canceled claims for previously broadcast holder commitment with txid {txid}");
				}
			}
			if let Some(prev_holder_commitment_tx) = &funding.prev_holder_commitment_tx {
				let txid = prev_holder_commitment_tx.trust().txid();
				if txid != *confirmed_commitment_txid {
					let mut found_claim = false;
					let mut outpoint = BitcoinOutPoint { txid, vout: 0 };
					for htlc in prev_holder_commitment_tx.nondust_htlcs() {
						if let Some(vout) = htlc.transaction_output_index {
							outpoint.vout = vout;
							if self.onchain_tx_handler.abandon_claim(&outpoint) {
								found_claim = true;
							}
						} else {
							debug_assert!(false, "Expected transaction output index for non-dust HTLC");
						}
					}
					if found_claim {
						log_trace!(logger, "Canceled claims for previously broadcast holder commitment with txid {txid}");
					}
				}
			}
		}
	}

	#[cfg(any(test, feature = "_test_utils", feature = "unsafe_revoked_tx_signing"))]
	/// Note that this includes possibly-locktimed-in-the-future transactions!
	#[rustfmt::skip]
	fn unsafe_get_latest_holder_commitment_txn<L: Logger>(
		&mut self, logger: &WithContext<L>
	) -> Vec<Transaction> {
		log_debug!(logger, "Getting signed copy of latest holder commitment transaction!");
		let commitment_tx = {
			let sig = self.onchain_tx_handler.signer.unsafe_sign_holder_commitment(
				&self.funding.channel_parameters, &self.funding.current_holder_commitment_tx,
				&self.onchain_tx_handler.secp_ctx,
			).expect("sign holder commitment");
			let redeem_script = self.funding.channel_parameters.make_funding_redeemscript();
			self.funding.current_holder_commitment_tx.add_holder_sig(&redeem_script, sig)
		};
		let mut holder_transactions = vec![commitment_tx];

		if self.channel_type_features().supports_anchors_zero_fee_htlc_tx()
			|| self.channel_type_features().supports_anchor_zero_fee_commitments()
		{
			// HTLC transactions in these channels require external funding before finalized,
			// so we return the commitment transaction alone here.
			//
			// In 0FC channels, we *could* use HTLC transactions to pay for fees on a
			// 0FC commitment transaction to save the fixed transaction overhead
			// (locktime + version), but we would still have to pay for fees using
			// external UTXOs to avoid invalidating the counterparty HTLC signature.
			// This is something we would consider in the future.
			//
			// Furthermore, we can't broadcast a HTLC claim transaction while the
			// anchor claim transaction and its parent are still unconfirmed due to the
			// current single-child restriction on TRUC transactions.
			return holder_transactions;
		}

		self.get_broadcasted_holder_htlc_descriptors(&self.funding, &self.funding.current_holder_commitment_tx)
			.into_iter()
			.for_each(|htlc_descriptor| {
				let txid = self.funding.current_holder_commitment_tx.trust().txid();
				let vout = htlc_descriptor.htlc.transaction_output_index
					.expect("Expected transaction output index for non-dust HTLC");
				let htlc_output = HolderHTLCOutput::build(htlc_descriptor, 0);
				if let Some(htlc_tx) = htlc_output.get_maybe_signed_htlc_tx(
					&mut self.onchain_tx_handler, &::bitcoin::OutPoint { txid, vout },
				) {
					if htlc_tx.is_fully_signed() {
						holder_transactions.push(htlc_tx.0);
					}
				}
			});

		holder_transactions
	}

	#[rustfmt::skip]
	fn block_connected<B: BroadcasterInterface, F: FeeEstimator, L: Logger>(
		&mut self, header: &Header, txdata: &TransactionData, height: u32, broadcaster: B,
		fee_estimator: F, logger: &WithContext<L>,
	) -> Vec<TransactionOutputs> {
		let block_hash = header.block_hash();
		self.best_block = BestBlock::new(block_hash, height);

		let bounded_fee_estimator = LowerBoundedFeeEstimator::new(fee_estimator);
		self.transactions_confirmed(header, txdata, height, broadcaster, &bounded_fee_estimator, logger)
	}

	#[rustfmt::skip]
	fn best_block_updated<B: BroadcasterInterface, F: FeeEstimator, L: Logger>(
		&mut self,
		header: &Header,
		height: u32,
		broadcaster: B,
		fee_estimator: &LowerBoundedFeeEstimator<F>,
		logger: &WithContext<L>,
	) -> Vec<TransactionOutputs> {
		let block_hash = header.block_hash();

		if height > self.best_block.height {
			self.best_block = BestBlock::new(block_hash, height);
			log_trace!(logger, "Connecting new block {} at height {}", block_hash, height);
			self.block_confirmed(height, block_hash, vec![], vec![], vec![], &broadcaster, &fee_estimator, logger)
		} else if block_hash != self.best_block.block_hash {
			self.best_block = BestBlock::new(block_hash, height);
			log_trace!(logger, "Best block re-orged, replaced with new block {} at height {}", block_hash, height);
			self.onchain_events_awaiting_threshold_conf.retain(|ref entry| entry.height <= height);
			let conf_target = self.closure_conf_target();
			self.onchain_tx_handler.blocks_disconnected(
				height, &broadcaster, conf_target, &self.destination_script, fee_estimator, logger,
			);
			Vec::new()
		} else { Vec::new() }
	}

	#[rustfmt::skip]
	fn transactions_confirmed<B: BroadcasterInterface, F: FeeEstimator, L: Logger>(
		&mut self,
		header: &Header,
		txdata: &TransactionData,
		height: u32,
		broadcaster: B,
		fee_estimator: &LowerBoundedFeeEstimator<F>,
		logger: &WithContext<L>,
	) -> Vec<TransactionOutputs> {
		let funding_seen_before = self.funding_seen_onchain;
		let txn_matched = self.filter_block(txdata);

		if !self.funding_seen_onchain {
			for &(_, tx) in txdata.iter() {
				let txid = tx.compute_txid();
				if txid == self.funding.funding_txid() ||
					self.pending_funding.iter().any(|f| f.funding_txid() == txid)
				{
					self.funding_seen_onchain = true;
					break;
				}
			}
		}

		for tx in &txn_matched {
			let mut output_val = Amount::ZERO;
			for out in tx.output.iter() {
				if out.value > Amount::MAX_MONEY { panic!("Value-overflowing transaction provided to block connected"); }
				output_val += out.value;
				if output_val > Amount::MAX_MONEY { panic!("Value-overflowing transaction provided to block connected"); }
			}
		}

		let block_hash = header.block_hash();

		// We may need to broadcast our holder commitment if we see a funding transaction reorg,
		// with a different funding transaction confirming. It's possible we process a
		// holder/counterparty commitment within this same block that would invalidate the one we're
		// intending to broadcast, so we track whether we should broadcast and wait until all
		// transactions in the block have been processed.
		let mut should_broadcast_commitment = false;

		let mut watch_outputs = Vec::new();
		let mut claimable_outpoints = Vec::new();

		if self.is_manual_broadcast && !funding_seen_before && self.funding_seen_onchain && self.holder_tx_signed
		{
			should_broadcast_commitment = true;
		}
		'tx_iter: for tx in &txn_matched {
			let txid = tx.compute_txid();
			log_trace!(logger, "Transaction {} confirmed in block {}", txid , block_hash);
			// If a transaction has already been confirmed, ensure we don't bother processing it duplicatively.
			if self.alternative_funding_confirmed.map(|(alternative_funding_txid, _)| alternative_funding_txid == txid).unwrap_or(false) {
				log_debug!(logger, "Skipping redundant processing of funding-spend tx {} as it was previously confirmed", txid);
				continue 'tx_iter;
			}
			if Some(txid) == self.funding_spend_confirmed {
				log_debug!(logger, "Skipping redundant processing of funding-spend tx {} as it was previously confirmed", txid);
				continue 'tx_iter;
			}
			for ev in self.onchain_events_awaiting_threshold_conf.iter() {
				if ev.txid == txid {
					if let Some(conf_hash) = ev.block_hash {
						assert_eq!(header.block_hash(), conf_hash,
							"Transaction {} was already confirmed and is being re-confirmed in a different block.\n\
							This indicates a severe bug in the transaction connection logic - a reorg should have been processed first!", ev.txid);
					}
					log_debug!(logger, "Skipping redundant processing of confirming tx {} as it was previously confirmed", txid);
					continue 'tx_iter;
				}
			}
			for htlc in self.htlcs_resolved_on_chain.iter() {
				if Some(txid) == htlc.resolving_txid {
					log_debug!(logger, "Skipping redundant processing of HTLC resolution tx {} as it was previously confirmed", txid);
					continue 'tx_iter;
				}
			}
			for spendable_txid in self.spendable_txids_confirmed.iter() {
				if txid == *spendable_txid {
					log_debug!(logger, "Skipping redundant processing of spendable tx {} as it was previously confirmed", txid);
					continue 'tx_iter;
				}
			}

			// A splice/dual-funded RBF transaction has confirmed. We can't promote the
			// `FundingScope` scope until we see the
			// [`ChannelMonitorUpdateStep::RenegotiatedFundingLocked`] for it, but we track the txid
			// so we know which holder commitment transaction we may need to broadcast.
			if let Some(alternative_funding) = self
				.pending_funding
				.iter()
				.find(|funding| funding.funding_txid() == txid)
			{
				assert!(self.alternative_funding_confirmed.is_none());
				assert!(
					!self.onchain_events_awaiting_threshold_conf.iter()
						.any(|e| matches!(e.event, OnchainEvent::AlternativeFundingConfirmation {}))
				);
				assert!(self.funding_spend_confirmed.is_none());
				assert!(
					!self.onchain_events_awaiting_threshold_conf.iter()
						.any(|e| matches!(e.event, OnchainEvent::FundingSpendConfirmation { .. }))
				);

				let (desc, msg) = if alternative_funding.is_splice() {
					debug_assert!(tx.input.iter().any(|input| {
						let funding_outpoint = self.funding.funding_outpoint().into_bitcoin_outpoint();
						input.previous_output == funding_outpoint
					}));
					("Splice", "splice_locked")
				} else {
					("Dual-funded RBF", "channel_ready")
				};
				let action = if self.holder_tx_signed || self.funding_spend_seen {
					", broadcasting holder commitment transaction".to_string()
				} else if !self.no_further_updates_allowed() {
					format!(", waiting for `{msg}` exchange")
				} else {
					"".to_string()
				};
				log_info!(logger, "{desc} confirmed with txid {txid}{action}");

				self.alternative_funding_confirmed = Some((txid, height));

				if self.no_further_updates_allowed() {
					// We can no longer rely on
					// [`ChannelMonitorUpdateStep::RenegotiatedFundingLocked`] to promote the
					// scope; do so when the funding is no longer under reorg risk.
					self.onchain_events_awaiting_threshold_conf.push(OnchainEventEntry {
						txid,
						transaction: Some((*tx).clone()),
						height,
						block_hash: Some(block_hash),
						event: OnchainEvent::AlternativeFundingConfirmation {},
					});
				}

				if self.holder_tx_signed || self.funding_spend_seen {
					// Cancel any previous claims that are no longer valid as they stemmed from a
					// different funding transaction.
					let new_holder_commitment_txid =
						alternative_funding.current_holder_commitment_tx.trust().txid();
					self.cancel_prev_commitment_claims(&logger, &new_holder_commitment_txid);

					// We either attempted to broadcast a holder commitment, or saw one confirm
					// onchain, so broadcast the new holder commitment for the confirmed funding to
					// claim our funds as the channel is no longer operational.
					should_broadcast_commitment = true;
				}

				continue 'tx_iter;
			}

			if tx.input.len() == 1 {
				// Assuming our keys were not leaked (in which case we're screwed no matter what),
				// commitment transactions and HTLC transactions will all only ever have one input
				// (except for HTLC transactions for channels with anchor outputs), which is an easy
				// way to filter out any potential non-matching txn for lazy filters.
				if let Some(funding_txid_spent) = core::iter::once(&self.funding)
					.chain(self.pending_funding.iter())
					.find(|funding| {
						let funding_outpoint = funding.funding_outpoint().into_bitcoin_outpoint();
						funding_outpoint == tx.input[0].previous_output
					})
					.map(|funding| funding.funding_txid())
				{
					assert_eq!(
						funding_txid_spent,
						self.alternative_funding_confirmed
							.map(|(txid, _)| txid)
							.unwrap_or_else(|| self.funding.funding_txid())
					);
					log_info!(logger, "Channel closed by funding output spend in txid {txid}");
					if !self.funding_spend_seen {
						self.pending_monitor_events.push(MonitorEvent::CommitmentTxConfirmed(()));
					}
					self.funding_spend_seen = true;

					let mut balance_spendable_csv = None;
					let mut commitment_tx_to_counterparty_output = None;

					// Is it a commitment transaction?
					if (tx.input[0].sequence.0 >> 8*3) as u8 == 0x80 && (tx.lock_time.to_consensus_u32() >> 8*3) as u8 == 0x20 {
						if let Some((mut new_outpoints, new_outputs)) = self.check_spend_holder_transaction(txid, &tx, height, &block_hash, &logger) {
							if !new_outputs.1.is_empty() {
								watch_outputs.push(new_outputs);
							}

							claimable_outpoints.append(&mut new_outpoints);
							balance_spendable_csv = Some(self.on_holder_tx_csv);
						} else {
							let mut new_watch_outputs = Vec::new();
							for (idx, outp) in tx.output.iter().enumerate() {
								new_watch_outputs.push((idx as u32, outp.clone()));
							}
							watch_outputs.push((txid, new_watch_outputs));

							let (mut new_outpoints, counterparty_output_idx_sats) =
								self.check_spend_counterparty_transaction(txid, &tx, height, &block_hash, &logger);
							commitment_tx_to_counterparty_output = counterparty_output_idx_sats;

							claimable_outpoints.append(&mut new_outpoints);
						}

						// We've just seen a commitment confirm, which conflicts with the holder
						// commitment we intend to broadcast
						if should_broadcast_commitment {
							log_info!(logger, "Canceling our queued holder commitment broadcast as we've found a conflict confirm instead");
							should_broadcast_commitment = false;
						}
					}

					self.onchain_events_awaiting_threshold_conf.push(OnchainEventEntry {
						txid,
						transaction: Some((*tx).clone()),
						height,
						block_hash: Some(block_hash),
						event: OnchainEvent::FundingSpendConfirmation {
							on_local_output_csv: balance_spendable_csv,
							commitment_tx_to_counterparty_output,
						},
					});

					// Now that we've detected a confirmed commitment transaction, attempt to cancel
					// pending claims for any commitments that were previously confirmed such that
					// we don't continue claiming inputs that no longer exist.
					self.cancel_prev_commitment_claims(&logger, &txid);
				}
			}
			if tx.input.len() >= 1 {
				// While all commitment transactions have one input, HTLC transactions may have more
				// if the HTLC was present in an anchor channel. HTLCs can also be resolved in a few
				// other ways which can have more than one output.
				for tx_input in &tx.input {
					let commitment_txid = tx_input.previous_output.txid;
					if let Some(&commitment_number) = self.counterparty_commitment_txn_on_chain.get(&commitment_txid) {
						let (mut new_outpoints, new_outputs_option) = self.check_spend_counterparty_htlc(
							&tx, commitment_number, &commitment_txid, height, &logger
						);
						claimable_outpoints.append(&mut new_outpoints);
						if let Some(new_outputs) = new_outputs_option {
							watch_outputs.push(new_outputs);
						}
						// Since there may be multiple HTLCs for this channel (all spending the
						// same commitment tx) being claimed by the counterparty within the same
						// transaction, and `check_spend_counterparty_htlc` already checks all the
						// ones relevant to this channel, we can safely break from our loop.
						break;
					}
				}
				self.is_resolving_htlc_output(&tx, height, &block_hash, logger);

				self.check_tx_and_push_spendable_outputs(&tx, height, &block_hash, logger);
			}
		}

		if height > self.best_block.height {
			self.best_block = BestBlock::new(block_hash, height);
		}

		if should_broadcast_commitment {
			let (mut claimables, mut outputs) =
				self.generate_claimable_outpoints_and_watch_outputs(None, false);
			claimable_outpoints.append(&mut claimables);
			watch_outputs.append(&mut outputs);
		}

		self.block_confirmed(height, block_hash, txn_matched, watch_outputs, claimable_outpoints, &broadcaster, &fee_estimator, logger)
	}

	/// Update state for new block(s)/transaction(s) confirmed. Note that the caller must update
	/// `self.best_block` before calling if a new best blockchain tip is available. More
	/// concretely, `self.best_block` must never be at a lower height than `conf_height`, avoiding
	/// complexity especially in
	/// `OnchainTx::update_claims_view_from_requests`/`OnchainTx::update_claims_view_from_matched_txn`.
	///
	/// `conf_height` should be set to the height at which any new transaction(s)/block(s) were
	/// confirmed at, even if it is not the current best height.
	#[rustfmt::skip]
	fn block_confirmed<B: BroadcasterInterface, F: FeeEstimator, L: Logger>(
		&mut self,
		conf_height: u32,
		conf_hash: BlockHash,
		txn_matched: Vec<&Transaction>,
		mut watch_outputs: Vec<TransactionOutputs>,
		mut claimable_outpoints: Vec<PackageTemplate>,
		broadcaster: &B,
		fee_estimator: &LowerBoundedFeeEstimator<F>,
		logger: &WithContext<L>,
	) -> Vec<TransactionOutputs> {
		log_trace!(logger, "Processing {} matched transactions for block at height {}.", txn_matched.len(), conf_height);
		debug_assert!(self.best_block.height >= conf_height);

		// Only generate claims if we haven't already done so (e.g., in transactions_confirmed).
		if claimable_outpoints.is_empty() {
			let should_broadcast = self.should_broadcast_holder_commitment_txn(logger);
			if let Some(payment_hash) = should_broadcast {
				let reason = ClosureReason::HTLCsTimedOut { payment_hash: Some(payment_hash) };
				let (mut new_outpoints, mut new_outputs) =
					self.generate_claimable_outpoints_and_watch_outputs(Some(reason), false);
				if !self.is_manual_broadcast || self.funding_seen_onchain {
					claimable_outpoints.append(&mut new_outpoints);
					watch_outputs.append(&mut new_outputs);
				} else {
					log_info!(logger, "Not broadcasting holder commitment for manual-broadcast channel before funding appears on-chain");
				}
			}
		}

		// Find which on-chain events have reached their confirmation threshold.
		let (onchain_events_reaching_threshold_conf, onchain_events_awaiting_threshold_conf): (Vec<_>, Vec<_>) =
			self.onchain_events_awaiting_threshold_conf.drain(..).partition(
				|entry| entry.has_reached_confirmation_threshold(&self.best_block));
		self.onchain_events_awaiting_threshold_conf = onchain_events_awaiting_threshold_conf;

		// Used to check for duplicate HTLC resolutions.
		#[cfg(debug_assertions)]
		let unmatured_htlcs: Vec<_> = self.onchain_events_awaiting_threshold_conf
			.iter()
			.filter_map(|entry| match &entry.event {
				OnchainEvent::HTLCUpdate { source, .. } => Some(source.clone()),
				_ => None,
			})
			.collect();
		#[cfg(debug_assertions)]
		let mut matured_htlcs = Vec::new();

		// Produce actionable events from on-chain events having reached their threshold.
		for entry in onchain_events_reaching_threshold_conf {
			match entry.event {
				OnchainEvent::HTLCUpdate { source, payment_hash, htlc_value_satoshis, commitment_tx_output_idx } => {
					// Check for duplicate HTLC resolutions.
					#[cfg(debug_assertions)]
					{
						debug_assert!(
							!unmatured_htlcs.contains(&source),
							"An unmature HTLC transaction conflicts with a maturing one; failed to \
							 call either transaction_unconfirmed for the conflicting transaction \
							 or blocks_disconnected for a block before it.");
						debug_assert!(
							!matured_htlcs.contains(&source),
							"A matured HTLC transaction conflicts with a maturing one; failed to \
							 call either transaction_unconfirmed for the conflicting transaction \
							 or blocks_disconnected for a block before it.");
						matured_htlcs.push(source.clone());
					}

					log_debug!(logger, "HTLC {} failure update in {} has got enough confirmations to be passed upstream",
						&payment_hash, entry.txid);
					self.pending_monitor_events.push(MonitorEvent::HTLCEvent(HTLCUpdate {
						payment_hash,
						payment_preimage: None,
						source,
						htlc_value_satoshis,
					}));
					self.htlcs_resolved_on_chain.push(IrrevocablyResolvedHTLC {
						commitment_tx_output_idx,
						resolving_txid: Some(entry.txid),
						resolving_tx: entry.transaction,
						payment_preimage: None,
					});
				},
				OnchainEvent::MaturingOutput { descriptor } => {
					log_debug!(logger, "Descriptor {} has got enough confirmations to be passed upstream", log_spendable!(descriptor));
					self.pending_events.push(Event::SpendableOutputs {
						outputs: vec![descriptor],
						channel_id: Some(self.channel_id()),
						counterparty_node_id: Some(self.counterparty_node_id),
					});
					self.spendable_txids_confirmed.push(entry.txid);
				},
				OnchainEvent::HTLCSpendConfirmation { commitment_tx_output_idx, preimage, .. } => {
					self.htlcs_resolved_on_chain.push(IrrevocablyResolvedHTLC {
						commitment_tx_output_idx: Some(commitment_tx_output_idx),
						resolving_txid: Some(entry.txid),
						resolving_tx: entry.transaction,
						payment_preimage: preimage,
					});
				},
				OnchainEvent::FundingSpendConfirmation { commitment_tx_to_counterparty_output, .. } => {
					self.funding_spend_confirmed = Some(entry.txid);
					self.confirmed_commitment_tx_counterparty_output = commitment_tx_to_counterparty_output;
					if self.alternative_funding_confirmed.is_none() {
						for funding in self.pending_funding.drain(..) {
							self.outputs_to_watch.remove(&funding.funding_txid());
							self.pending_events.push(Event::DiscardFunding {
								channel_id: self.channel_id,
								funding_info: crate::events::FundingInfo::OutPoint {
									outpoint: funding.funding_outpoint(),
								},
							});
						}
					}
				},
				OnchainEvent::AlternativeFundingConfirmation {} => {
					// An alternative funding transaction has irrevocably confirmed and we're no
					// longer allowing monitor updates, so promote the `FundingScope` now.
					debug_assert!(self.no_further_updates_allowed());
					debug_assert_ne!(self.funding.funding_txid(), entry.txid);
					if let Err(_) = self.promote_funding(entry.txid) {
						debug_assert!(false);
						log_error!(logger, "Missing scope for alternative funding confirmation with txid {}", entry.txid);
					}
				},
			}
		}

		if self.no_further_updates_allowed() {
			// Fail back HTLCs on backwards channels if they expire within
			// `LATENCY_GRACE_PERIOD_BLOCKS` blocks and the channel is closed (i.e. we're at a
			// point where no further off-chain updates will be accepted). If we haven't seen the
			// preimage for an HTLC by the time the previous hop's timeout expires, we've lost that
			// HTLC, so we might as well fail it back instead of having our counterparty force-close
			// the inbound channel.
			let current_counterparty_htlcs = if let Some(txid) = self.funding.current_counterparty_commitment_txid {
				if let Some(htlc_outputs) = self.funding.counterparty_claimable_outpoints.get(&txid) {
					Some(htlc_outputs.iter().map(|&(ref a, ref b)| (a, b.as_ref().map(|boxed| &**boxed))))
				} else { None }
			} else { None }.into_iter().flatten();

			let prev_counterparty_htlcs = if let Some(txid) = self.funding.prev_counterparty_commitment_txid {
				if let Some(htlc_outputs) = self.funding.counterparty_claimable_outpoints.get(&txid) {
					Some(htlc_outputs.iter().map(|&(ref a, ref b)| (a, b.as_ref().map(|boxed| &**boxed))))
				} else { None }
			} else { None }.into_iter().flatten();

			let htlcs = holder_commitment_htlcs!(self, CURRENT_WITH_SOURCES)
				.chain(current_counterparty_htlcs)
				.chain(prev_counterparty_htlcs);

			let height = self.best_block.height;
			for (htlc, source_opt) in htlcs {
				// Only check forwarded HTLCs' previous hops
				let source = match source_opt {
					Some(source) => source,
					None => continue,
				};
				let inbound_htlc_expiry = match source.inbound_htlc_expiry() {
					Some(cltv_expiry) => cltv_expiry,
					None => continue,
				};
				let max_expiry_height = height.saturating_add(LATENCY_GRACE_PERIOD_BLOCKS);
				if inbound_htlc_expiry > max_expiry_height {
					continue;
				}
				let duplicate_event = self.pending_monitor_events.iter().any(
					|update| if let &MonitorEvent::HTLCEvent(ref upd) = update {
						upd.source == *source
					} else { false });
				if duplicate_event {
					continue;
				}
				if !self.failed_back_htlc_ids.insert(SentHTLCId::from_source(source)) {
					continue;
				}
				if !duplicate_event {
					log_error!(logger, "Failing back HTLC {} upstream to preserve the \
						channel as the forward HTLC hasn't resolved and our backward HTLC \
						expires soon at {}", log_bytes!(htlc.payment_hash.0), inbound_htlc_expiry);
					self.pending_monitor_events.push(MonitorEvent::HTLCEvent(HTLCUpdate {
						source: source.clone(),
						payment_preimage: None,
						payment_hash: htlc.payment_hash,
						htlc_value_satoshis: Some(htlc.amount_msat / 1000),
					}));
				}
			}
		}

		let conf_target = self.closure_conf_target();
		self.onchain_tx_handler.update_claims_view_from_requests(
			claimable_outpoints, conf_height, self.best_block.height, broadcaster, conf_target,
			&self.destination_script, fee_estimator, logger,
		);
		self.onchain_tx_handler.update_claims_view_from_matched_txn(
			&txn_matched, conf_height, conf_hash, self.best_block.height, broadcaster, conf_target,
			&self.destination_script, fee_estimator, logger,
		);

		// Determine new outputs to watch by comparing against previously known outputs to watch,
		// updating the latter in the process.
		watch_outputs.retain(|&(ref txid, ref txouts)| {
			let idx_and_scripts = txouts.iter().map(|o| (o.0, o.1.script_pubkey.clone())).collect();
			self.outputs_to_watch.insert(txid.clone(), idx_and_scripts).is_none()
		});
		#[cfg(test)]
		{
			// If we see a transaction for which we registered outputs previously,
			// make sure the registered scriptpubkey at the expected index match
			// the actual transaction output one. We failed this case before #653.
			for tx in &txn_matched {
				if let Some(outputs) = self.get_outputs_to_watch().get(&tx.compute_txid()) {
					for idx_and_script in outputs.iter() {
						assert!((idx_and_script.0 as usize) < tx.output.len());
						assert_eq!(tx.output[idx_and_script.0 as usize].script_pubkey, idx_and_script.1);
					}
				}
			}
		}
		watch_outputs
	}

	#[rustfmt::skip]
	fn blocks_disconnected<B: BroadcasterInterface, F: FeeEstimator, L: Logger>(
		&mut self, fork_point: BestBlock, broadcaster: B, fee_estimator: F, logger: &WithContext<L>
	) {
		let new_height = fork_point.height;
		log_trace!(logger, "Block(s) disconnected to height {}", new_height);
		assert!(self.best_block.height > fork_point.height,
			"Blocks disconnected must indicate disconnection from the current best height, i.e. the new chain tip must be lower than the previous best height");

		//We may discard:
		//- htlc update there as failure-trigger tx (revoked commitment tx, non-revoked commitment tx, HTLC-timeout tx) has been disconnected
		//- maturing spendable output has transaction paying us has been disconnected
		self.onchain_events_awaiting_threshold_conf.retain(|ref entry| entry.height <= new_height);

		// TODO: Replace with `take_if` once our MSRV is >= 1.80.
		let mut should_broadcast_commitment = false;
		if let Some((_, conf_height)) = self.alternative_funding_confirmed.as_ref() {
			if *conf_height > new_height {
				self.alternative_funding_confirmed.take();
				if self.holder_tx_signed || self.funding_spend_seen {
					// Cancel any previous claims that are no longer valid as they stemmed from a
					// different funding transaction.
					let new_holder_commitment_txid =
						self.funding.current_holder_commitment_tx.trust().txid();
					self.cancel_prev_commitment_claims(&logger, &new_holder_commitment_txid);

					should_broadcast_commitment = true;
				}
			}
		}

		let bounded_fee_estimator = LowerBoundedFeeEstimator::new(fee_estimator);
		let conf_target = self.closure_conf_target();
		self.onchain_tx_handler.blocks_disconnected(
			new_height, &broadcaster, conf_target, &self.destination_script, &bounded_fee_estimator, logger
		);

		// Only attempt to broadcast the new commitment after the `block_disconnected` call above so that
		// it doesn't get removed from the set of pending claims.
		if should_broadcast_commitment {
			self.queue_latest_holder_commitment_txn_for_broadcast(&broadcaster, &bounded_fee_estimator, logger, true);
		}

		self.best_block = fork_point;
	}

	#[rustfmt::skip]
	fn transaction_unconfirmed<B: BroadcasterInterface, F: FeeEstimator, L: Logger>(
		&mut self,
		txid: &Txid,
		broadcaster: B,
		fee_estimator: &LowerBoundedFeeEstimator<F>,
		logger: &WithContext<L>,
	) {
		let mut removed_height = None;
		for entry in self.onchain_events_awaiting_threshold_conf.iter() {
			if entry.txid == *txid {
				removed_height = Some(entry.height);
				break;
			}
		}

		if let Some(removed_height) = removed_height {
			log_info!(logger, "transaction_unconfirmed of txid {} implies height {} was reorg'd out", txid, removed_height);
			self.onchain_events_awaiting_threshold_conf.retain(|ref entry| if entry.height >= removed_height {
				log_info!(logger, "Transaction {} reorg'd out", entry.txid);
				false
			} else { true });
		}

		debug_assert!(!self.onchain_events_awaiting_threshold_conf.iter().any(|ref entry| entry.txid == *txid));

		// TODO: Replace with `take_if` once our MSRV is >= 1.80.
		let mut should_broadcast_commitment = false;
		if let Some((alternative_funding_txid, _)) = self.alternative_funding_confirmed.as_ref() {
			if alternative_funding_txid == txid {
				self.alternative_funding_confirmed.take();
				if self.holder_tx_signed || self.funding_spend_seen {
					// Cancel any previous claims that are no longer valid as they stemmed from a
					// different funding transaction.
					let new_holder_commitment_txid =
						self.funding.current_holder_commitment_tx.trust().txid();
					self.cancel_prev_commitment_claims(&logger, &new_holder_commitment_txid);

					should_broadcast_commitment = true;
				}
			}
		}

		let conf_target = self.closure_conf_target();
		self.onchain_tx_handler.transaction_unconfirmed(
			txid, &broadcaster, conf_target, &self.destination_script, fee_estimator, logger
		);

		// Only attempt to broadcast the new commitment after the `transaction_unconfirmed` call above so
		//  that it doesn't get removed from the set of pending claims.
		if should_broadcast_commitment {
			self.queue_latest_holder_commitment_txn_for_broadcast(&broadcaster, fee_estimator, logger, true);
		}
	}

	/// Filters a block's `txdata` for transactions spending watched outputs or for any child
	/// transactions thereof.
	#[rustfmt::skip]
	fn filter_block<'a>(&self, txdata: &TransactionData<'a>) -> Vec<&'a Transaction> {
		let mut matched_txn = new_hash_set();
		txdata.iter().filter(|&&(_, tx)| {
			let mut matches = self.spends_watched_output(tx);
			for input in tx.input.iter() {
				if matches { break; }
				if matched_txn.contains(&input.previous_output.txid) {
					matches = true;
				}
			}
			if matches {
				matched_txn.insert(tx.compute_txid());
			}
			matches
		}).map(|(_, tx)| *tx).collect()
	}

	/// Checks if a given transaction spends any watched outputs.
	#[rustfmt::skip]
	fn spends_watched_output(&self, tx: &Transaction) -> bool {
		for input in tx.input.iter() {
			if let Some(outputs) = self.get_outputs_to_watch().get(&input.previous_output.txid) {
				for (idx, _script_pubkey) in outputs.iter() {
					if *idx == input.previous_output.vout {
						#[cfg(test)]
						{
							// If the expected script is a known type, check that the witness
							// appears to be spending the correct type (ie that the match would
							// actually succeed in BIP 158/159-style filters).
							if _script_pubkey.is_p2wsh() {
								if input.witness.last().unwrap().to_vec() == deliberately_bogus_accepted_htlc_witness_program() {
									// In at least one test we use a deliberately bogus witness
									// script which hit an old panic. Thus, we check for that here
									// and avoid the assert if its the expected bogus script.
									return true;
								}

								assert_eq!(&bitcoin::Address::p2wsh(&ScriptBuf::from(input.witness.last().unwrap().to_vec()), bitcoin::Network::Bitcoin).script_pubkey(), _script_pubkey);
							} else if _script_pubkey.is_p2wpkh() {
								assert_eq!(&bitcoin::Address::p2wpkh(&bitcoin::CompressedPublicKey(bitcoin::PublicKey::from_slice(&input.witness.last().unwrap()).unwrap().inner), bitcoin::Network::Bitcoin).script_pubkey(), _script_pubkey);
							} else if _script_pubkey == &chan_utils::shared_anchor_script_pubkey() {
								assert!(input.witness.is_empty());
							} else { panic!(); }
						}
						return true;
					}
				}
			}
		}

		false
	}

	#[rustfmt::skip]
	fn should_broadcast_holder_commitment_txn<L: Logger>(
		&self, logger: &WithContext<L>
	) -> Option<PaymentHash> {
		// There's no need to broadcast our commitment transaction if we've seen one confirmed (even
		// with 1 confirmation) as it'll be rejected as duplicate/conflicting.
		if self.funding_spend_confirmed.is_some() ||
			self.onchain_events_awaiting_threshold_conf.iter().find(|event| match event.event {
				OnchainEvent::FundingSpendConfirmation { .. } => true,
				_ => false,
			}).is_some()
		{
			return None;
		}
		// We need to consider all HTLCs which are:
		//  * in any unrevoked counterparty commitment transaction, as they could broadcast said
		//    transactions and we'd end up in a race, or
		//  * are in our latest holder commitment transaction, as this is the thing we will
		//    broadcast if we go on-chain.
		// Note that we consider HTLCs which were below dust threshold here - while they don't
		// strictly imply that we need to fail the channel, we need to go ahead and fail them back
		// to the source, and if we don't fail the channel we will have to ensure that the next
		// updates that peer sends us are update_fails, failing the channel if not. It's probably
		// easier to just fail the channel as this case should be rare enough anyway.
		let height = self.best_block.height;
		macro_rules! scan_commitment {
			($htlcs: expr, $holder_tx: expr) => {
				for ref htlc in $htlcs {
					// For inbound HTLCs which we know the preimage for, we have to ensure we hit the
					// chain with enough room to claim the HTLC without our counterparty being able to
					// time out the HTLC first.
					// For outbound HTLCs which our counterparty hasn't failed/claimed, our primary
					// concern is being able to claim the corresponding inbound HTLC (on another
					// channel) before it expires. In fact, we don't even really care if our
					// counterparty here claims such an outbound HTLC after it expired as long as we
					// can still claim the corresponding HTLC. Thus, to avoid needlessly hitting the
					// chain when our counterparty is waiting for expiration to off-chain fail an HTLC
					// we give ourselves a few blocks of headroom after expiration before going
					// on-chain for an expired HTLC.
					let htlc_outbound = $holder_tx == htlc.offered;
					if ( htlc_outbound && htlc.cltv_expiry + LATENCY_GRACE_PERIOD_BLOCKS <= height) ||
					   (!htlc_outbound && htlc.cltv_expiry <= height + CLTV_CLAIM_BUFFER && self.payment_preimages.contains_key(&htlc.payment_hash)) {
						log_info!(logger, "Force-closing channel due to {} HTLC timeout - HTLC with payment hash {} expires at {}", if htlc_outbound { "outbound" } else { "inbound"}, htlc.payment_hash, htlc.cltv_expiry);
						return Some(htlc.payment_hash);
					}
				}
			}
		}

		scan_commitment!(holder_commitment_htlcs!(self, CURRENT), true);

		if let Some(ref txid) = self.funding.current_counterparty_commitment_txid {
			if let Some(ref htlc_outputs) = self.funding.counterparty_claimable_outpoints.get(txid) {
				scan_commitment!(htlc_outputs.iter().map(|&(ref a, _)| a), false);
			}
		}
		if let Some(ref txid) = self.funding.prev_counterparty_commitment_txid {
			if let Some(ref htlc_outputs) = self.funding.counterparty_claimable_outpoints.get(txid) {
				scan_commitment!(htlc_outputs.iter().map(|&(ref a, _)| a), false);
			}
		}

		None
	}

	/// Check if any transaction broadcasted is resolving HTLC output by a success or timeout on a holder
	/// or counterparty commitment tx, if so send back the source, preimage if found and payment_hash of resolved HTLC
	#[rustfmt::skip]
	fn is_resolving_htlc_output<L: Logger>(
		&mut self, tx: &Transaction, height: u32, block_hash: &BlockHash, logger: &WithContext<L>,
	) {
		let funding_spent = get_confirmed_funding_scope!(self);

		'outer_loop: for input in &tx.input {
			let mut payment_data = None;
			let htlc_claim = HTLCClaim::from_witness(&input.witness);
			let revocation_sig_claim = htlc_claim == Some(HTLCClaim::Revocation);
			let accepted_preimage_claim = htlc_claim == Some(HTLCClaim::AcceptedPreimage);
			#[cfg(not(fuzzing))]
			let accepted_timeout_claim = htlc_claim == Some(HTLCClaim::AcceptedTimeout);
			let offered_preimage_claim = htlc_claim == Some(HTLCClaim::OfferedPreimage);
			#[cfg(not(fuzzing))]
			let offered_timeout_claim = htlc_claim == Some(HTLCClaim::OfferedTimeout);

			let mut payment_preimage = PaymentPreimage([0; 32]);
			if offered_preimage_claim || accepted_preimage_claim {
				payment_preimage.0.copy_from_slice(input.witness.second_to_last().unwrap());
			}

			macro_rules! log_claim {
				($tx_info: expr, $holder_tx: expr, $htlc: expr, $source_avail: expr) => {
					let outbound_htlc = $holder_tx == $htlc.offered;
					// HTLCs must either be claimed by a matching script type or through the
					// revocation path:
					#[cfg(not(fuzzing))] // Note that the fuzzer is not bound by pesky things like "signatures"
					debug_assert!(!$htlc.offered || offered_preimage_claim || offered_timeout_claim || revocation_sig_claim);
					#[cfg(not(fuzzing))] // Note that the fuzzer is not bound by pesky things like "signatures"
					debug_assert!($htlc.offered || accepted_preimage_claim || accepted_timeout_claim || revocation_sig_claim);
					// Further, only exactly one of the possible spend paths should have been
					// matched by any HTLC spend:
					#[cfg(not(fuzzing))] // Note that the fuzzer is not bound by pesky things like "signatures"
					debug_assert_eq!(accepted_preimage_claim as u8 + accepted_timeout_claim as u8 +
					                 offered_preimage_claim as u8 + offered_timeout_claim as u8 +
					                 revocation_sig_claim as u8, 1);
					if ($holder_tx && revocation_sig_claim) ||
							(outbound_htlc && !$source_avail && (accepted_preimage_claim || offered_preimage_claim)) {
						log_error!(logger, "Input spending {} ({}:{}) in {} resolves {} HTLC with payment hash {} with {}!",
							$tx_info, input.previous_output.txid, input.previous_output.vout, tx.compute_txid(),
							if outbound_htlc { "outbound" } else { "inbound" }, &$htlc.payment_hash,
							if revocation_sig_claim { "revocation sig" } else { "preimage claim after we'd passed the HTLC resolution back. We can likely claim the HTLC output with a revocation claim" });
					} else {
						log_info!(logger, "Input spending {} ({}:{}) in {} resolves {} HTLC with payment hash {} with {}",
							$tx_info, input.previous_output.txid, input.previous_output.vout, tx.compute_txid(),
							if outbound_htlc { "outbound" } else { "inbound" }, &$htlc.payment_hash,
							if revocation_sig_claim { "revocation sig" } else if accepted_preimage_claim || offered_preimage_claim { "preimage" } else { "timeout" });
					}
				}
			}

			macro_rules! check_htlc_valid_counterparty {
				($htlc_output: expr, $per_commitment_data: expr) => {
						for &(ref pending_htlc, ref pending_source) in $per_commitment_data {
							if pending_htlc.payment_hash == $htlc_output.payment_hash && pending_htlc.amount_msat == $htlc_output.amount_msat {
								if let &Some(ref source) = pending_source {
									log_claim!("revoked counterparty commitment tx", false, pending_htlc, true);
									payment_data = Some(((**source).clone(), $htlc_output.payment_hash, $htlc_output.amount_msat));
									break;
								}
							}
						}
				}
			}

			macro_rules! scan_commitment {
				($funding_spent: expr, $htlcs: expr, $tx_info: expr, $holder_tx: expr) => {
					for (ref htlc_output, source_option) in $htlcs {
						if Some(input.previous_output.vout) == htlc_output.transaction_output_index {
							if let Some(ref source) = source_option {
								log_claim!($tx_info, $holder_tx, htlc_output, true);
								// We have a resolution of an HTLC either from one of our latest
								// holder commitment transactions or an unrevoked counterparty commitment
								// transaction. This implies we either learned a preimage, the HTLC
								// has timed out, or we screwed up. In any case, we should now
								// resolve the source HTLC with the original sender.
								payment_data = Some(((*source).clone(), htlc_output.payment_hash, htlc_output.amount_msat));
							} else if !$holder_tx {
								if let Some(current_counterparty_commitment_txid) = &$funding_spent.current_counterparty_commitment_txid {
									check_htlc_valid_counterparty!(htlc_output, $funding_spent.counterparty_claimable_outpoints.get(current_counterparty_commitment_txid).unwrap());
								}
								if payment_data.is_none() {
									if let Some(prev_counterparty_commitment_txid) = &$funding_spent.prev_counterparty_commitment_txid {
										check_htlc_valid_counterparty!(htlc_output, $funding_spent.counterparty_claimable_outpoints.get(prev_counterparty_commitment_txid).unwrap());
									}
								}
							}
							if payment_data.is_none() {
								log_claim!($tx_info, $holder_tx, htlc_output, false);
								let outbound_htlc = $holder_tx == htlc_output.offered;
								self.onchain_events_awaiting_threshold_conf.push(OnchainEventEntry {
									txid: tx.compute_txid(), height, block_hash: Some(*block_hash), transaction: Some(tx.clone()),
									event: OnchainEvent::HTLCSpendConfirmation {
										commitment_tx_output_idx: input.previous_output.vout,
										preimage: if accepted_preimage_claim || offered_preimage_claim {
											Some(payment_preimage) } else { None },
										// If this is a payment to us (ie !outbound_htlc), wait for
										// the CSV delay before dropping the HTLC from claimable
										// balance if the claim was an HTLC-Success transaction (ie
										// accepted_preimage_claim).
										on_to_local_output_csv: if accepted_preimage_claim && !outbound_htlc {
											Some(self.on_holder_tx_csv) } else { None },
									},
								});
								continue 'outer_loop;
							}
						}
					}
				}
			}

			if input.previous_output.txid == funding_spent.current_holder_commitment_tx.trust().txid() {
				scan_commitment!(
					funding_spent, holder_commitment_htlcs!(self, CURRENT_WITH_SOURCES),
					"our latest holder commitment tx", true
				);
			}
			if let Some(prev_holder_commitment_tx) = funding_spent.prev_holder_commitment_tx.as_ref() {
				if input.previous_output.txid == prev_holder_commitment_tx.trust().txid() {
					scan_commitment!(
						funding_spent, holder_commitment_htlcs!(self, PREV_WITH_SOURCES).unwrap(),
						"our previous holder commitment tx", true
					);
				}
			}
			if let Some(ref htlc_outputs) = funding_spent.counterparty_claimable_outpoints.get(&input.previous_output.txid) {
				let htlcs = htlc_outputs.iter()
					.map(|&(ref a, ref b)| (a, b.as_ref().map(|boxed| &**boxed)));
				scan_commitment!(funding_spent, htlcs, "counterparty commitment tx", false);
			}

			// Check that scan_commitment, above, decided there is some source worth relaying an
			// HTLC resolution backwards to and figure out whether we learned a preimage from it.
			if let Some((source, payment_hash, amount_msat)) = payment_data {
				if accepted_preimage_claim {
					if !self.pending_monitor_events.iter().any(
						|update| if let &MonitorEvent::HTLCEvent(ref upd) = update { upd.source == source } else { false }) {
						self.onchain_events_awaiting_threshold_conf.push(OnchainEventEntry {
							txid: tx.compute_txid(),
							height,
							block_hash: Some(*block_hash),
							transaction: Some(tx.clone()),
							event: OnchainEvent::HTLCSpendConfirmation {
								commitment_tx_output_idx: input.previous_output.vout,
								preimage: Some(payment_preimage),
								on_to_local_output_csv: None,
							},
						});
						self.counterparty_fulfilled_htlcs.insert(SentHTLCId::from_source(&source), payment_preimage);
						self.pending_monitor_events.push(MonitorEvent::HTLCEvent(HTLCUpdate {
							source,
							payment_preimage: Some(payment_preimage),
							payment_hash,
							htlc_value_satoshis: Some(amount_msat / 1000),
						}));
					}
				} else if offered_preimage_claim {
					if !self.pending_monitor_events.iter().any(
						|update| if let &MonitorEvent::HTLCEvent(ref upd) = update {
							upd.source == source
						} else { false }) {
						self.onchain_events_awaiting_threshold_conf.push(OnchainEventEntry {
							txid: tx.compute_txid(),
							transaction: Some(tx.clone()),
							height,
							block_hash: Some(*block_hash),
							event: OnchainEvent::HTLCSpendConfirmation {
								commitment_tx_output_idx: input.previous_output.vout,
								preimage: Some(payment_preimage),
								on_to_local_output_csv: None,
							},
						});
						self.counterparty_fulfilled_htlcs.insert(SentHTLCId::from_source(&source), payment_preimage);
						self.pending_monitor_events.push(MonitorEvent::HTLCEvent(HTLCUpdate {
							source,
							payment_preimage: Some(payment_preimage),
							payment_hash,
							htlc_value_satoshis: Some(amount_msat / 1000),
						}));
					}
				} else {
					self.onchain_events_awaiting_threshold_conf.retain(|ref entry| {
						if entry.height != height { return true; }
						match entry.event {
							OnchainEvent::HTLCUpdate { source: ref htlc_source, .. } => {
								*htlc_source != source
							},
							_ => true,
						}
					});
					let entry = OnchainEventEntry {
						txid: tx.compute_txid(),
						transaction: Some(tx.clone()),
						height,
						block_hash: Some(*block_hash),
						event: OnchainEvent::HTLCUpdate {
							source,
							payment_hash,
							htlc_value_satoshis: Some(amount_msat / 1000),
							commitment_tx_output_idx: Some(input.previous_output.vout),
						},
					};
					log_info!(logger, "Failing HTLC with payment_hash {} timeout by a spend tx, waiting for confirmation (at height {})", &payment_hash, entry.confirmation_threshold());
					self.onchain_events_awaiting_threshold_conf.push(entry);
				}
			}
		}
	}

	#[rustfmt::skip]
	fn get_spendable_outputs(&self, funding_spent: &FundingScope, tx: &Transaction) -> Vec<SpendableOutputDescriptor> {
		let mut spendable_outputs = Vec::new();
		for (i, outp) in tx.output.iter().enumerate() {
			if outp.script_pubkey == self.destination_script {
				spendable_outputs.push(SpendableOutputDescriptor::StaticOutput {
					outpoint: OutPoint { txid: tx.compute_txid(), index: i as u16 },
					output: outp.clone(),
					channel_keys_id: Some(self.channel_keys_id),
				});
			}
			if let Some(ref broadcasted_holder_revokable_script) = self.broadcasted_holder_revokable_script {
				if broadcasted_holder_revokable_script.0 == outp.script_pubkey {
					spendable_outputs.push(SpendableOutputDescriptor::DelayedPaymentOutput(DelayedPaymentOutputDescriptor {
						outpoint: OutPoint { txid: tx.compute_txid(), index: i as u16 },
						per_commitment_point: broadcasted_holder_revokable_script.1,
						to_self_delay: self.on_holder_tx_csv,
						output: outp.clone(),
						revocation_pubkey: broadcasted_holder_revokable_script.2,
						channel_keys_id: self.channel_keys_id,
						channel_value_satoshis: funding_spent.channel_parameters.channel_value_satoshis,
						channel_transaction_parameters: Some(funding_spent.channel_parameters.clone()),
					}));
				}
			}
			if self.counterparty_payment_script == outp.script_pubkey {
				spendable_outputs.push(SpendableOutputDescriptor::StaticPaymentOutput(StaticPaymentOutputDescriptor {
					outpoint: OutPoint { txid: tx.compute_txid(), index: i as u16 },
					output: outp.clone(),
					channel_keys_id: self.channel_keys_id,
					channel_value_satoshis: funding_spent.channel_parameters.channel_value_satoshis,
					channel_transaction_parameters: Some(funding_spent.channel_parameters.clone()),
				}));
			}
			if self.shutdown_script.as_ref() == Some(&outp.script_pubkey) {
				spendable_outputs.push(SpendableOutputDescriptor::StaticOutput {
					outpoint: OutPoint { txid: tx.compute_txid(), index: i as u16 },
					output: outp.clone(),
					channel_keys_id: Some(self.channel_keys_id),
				});
			}
		}
		spendable_outputs
	}

	/// Checks if the confirmed transaction is paying funds back to some address we can assume to
	/// own.
	#[rustfmt::skip]
	fn check_tx_and_push_spendable_outputs<L: Logger>(
		&mut self, tx: &Transaction, height: u32, block_hash: &BlockHash, logger: &WithContext<L>,
	) {
		let funding_spent = get_confirmed_funding_scope!(self);
		for spendable_output in self.get_spendable_outputs(funding_spent, tx) {
			let entry = OnchainEventEntry {
				txid: tx.compute_txid(),
				transaction: Some(tx.clone()),
				height,
				block_hash: Some(*block_hash),
				event: OnchainEvent::MaturingOutput { descriptor: spendable_output.clone() },
			};
			log_info!(logger, "Received spendable output {}, spendable at height {}", log_spendable!(spendable_output), entry.confirmation_threshold());
			self.onchain_events_awaiting_threshold_conf.push(entry);
		}
	}

	fn channel_type_features(&self) -> &ChannelTypeFeatures {
		&self.funding.channel_parameters.channel_type_features
	}
}

impl<Signer: EcdsaChannelSigner, T: BroadcasterInterface, F: FeeEstimator, L: Logger> chain::Listen
	for (ChannelMonitor<Signer>, T, F, L)
{
	fn filtered_block_connected(&self, header: &Header, txdata: &TransactionData, height: u32) {
		self.0.block_connected(header, txdata, height, &self.1, &self.2, &self.3);
	}

	fn blocks_disconnected(&self, fork_point: BestBlock) {
		self.0.blocks_disconnected(fork_point, &self.1, &self.2, &self.3);
	}
}

impl<Signer: EcdsaChannelSigner, M, T: BroadcasterInterface, F: FeeEstimator, L: Logger>
	chain::Confirm for (M, T, F, L)
where
	M: Deref<Target = ChannelMonitor<Signer>>,
{
	fn transactions_confirmed(&self, header: &Header, txdata: &TransactionData, height: u32) {
		self.0.transactions_confirmed(header, txdata, height, &self.1, &self.2, &self.3);
	}

	fn transaction_unconfirmed(&self, txid: &Txid) {
		self.0.transaction_unconfirmed(txid, &self.1, &self.2, &self.3);
	}

	fn best_block_updated(&self, header: &Header, height: u32) {
		self.0.best_block_updated(header, height, &self.1, &self.2, &self.3);
	}

	fn get_relevant_txids(&self) -> Vec<(Txid, u32, Option<BlockHash>)> {
		self.0.get_relevant_txids()
	}
}

const MAX_ALLOC_SIZE: usize = 64 * 1024;

impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP)>
	for (BlockHash, ChannelMonitor<SP::EcdsaSigner>)
{
	fn read<R: io::Read>(reader: &mut R, args: (&'a ES, &'b SP)) -> Result<Self, DecodeError> {
		match <Option<Self>>::read(reader, args) {
			Ok(Some(res)) => Ok(res),
			Ok(None) => Err(DecodeError::UnknownRequiredFeature),
			Err(e) => Err(e),
		}
	}
}

impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP)>
	for Option<(BlockHash, ChannelMonitor<SP::EcdsaSigner>)>
{
	#[rustfmt::skip]
	fn read<R: io::Read>(reader: &mut R, args: (&'a ES, &'b SP)) -> Result<Self, DecodeError> {
		macro_rules! unwrap_obj {
			($key: expr) => {
				match $key {
					Ok(res) => res,
					Err(_) => return Err(DecodeError::InvalidValue),
				}
			}
		}

		let (entropy_source, signer_provider) = args;

		let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);

		let latest_update_id: u64 = Readable::read(reader)?;
		let commitment_transaction_number_obscure_factor = <U48 as Readable>::read(reader)?.0;

		let destination_script = Readable::read(reader)?;
		let broadcasted_holder_revokable_script = match <u8 as Readable>::read(reader)? {
			0 => {
				let revokable_address = Readable::read(reader)?;
				let per_commitment_point = Readable::read(reader)?;
				let revokable_script = Readable::read(reader)?;
				Some((revokable_address, per_commitment_point, revokable_script))
			},
			1 => { None },
			_ => return Err(DecodeError::InvalidValue),
		};
		let mut counterparty_payment_script: ScriptBuf = Readable::read(reader)?;
		let shutdown_script = {
			let script = <ScriptBuf as Readable>::read(reader)?;
			if script.is_empty() { None } else { Some(script) }
		};

		let channel_keys_id = Readable::read(reader)?;
		let holder_revocation_basepoint = Readable::read(reader)?;
		// Technically this can fail and serialize fail a round-trip, but only for serialization of
		// barely-init'd ChannelMonitors that we can't do anything with.
		let outpoint = OutPoint {
			txid: Readable::read(reader)?,
			index: Readable::read(reader)?,
		};
		let _funding_script: ScriptBuf = Readable::read(reader)?;
		let current_counterparty_commitment_txid = Readable::read(reader)?;
		let prev_counterparty_commitment_txid = Readable::read(reader)?;

		let counterparty_commitment_params = Readable::read(reader)?;
		let _funding_redeemscript: ScriptBuf = Readable::read(reader)?;
		let channel_value_satoshis = Readable::read(reader)?;

		let their_cur_per_commitment_points = {
			let first_idx = <U48 as Readable>::read(reader)?.0;
			if first_idx == 0 {
				None
			} else {
				let first_point = Readable::read(reader)?;
				let second_point_slice: [u8; 33] = Readable::read(reader)?;
				if second_point_slice[0..32] == [0; 32] && second_point_slice[32] == 0 {
					Some((first_idx, first_point, None))
				} else {
					Some((first_idx, first_point, Some(unwrap_obj!(PublicKey::from_slice(&second_point_slice)))))
				}
			}
		};

		let on_holder_tx_csv: u16 = Readable::read(reader)?;

		let commitment_secrets = Readable::read(reader)?;

		macro_rules! read_htlc_in_commitment {
			() => {
				{
					let offered: bool = Readable::read(reader)?;
					let amount_msat: u64 = Readable::read(reader)?;
					let cltv_expiry: u32 = Readable::read(reader)?;
					let payment_hash: PaymentHash = Readable::read(reader)?;
					let transaction_output_index: Option<u32> = Readable::read(reader)?;

					HTLCOutputInCommitment {
						offered, amount_msat, cltv_expiry, payment_hash, transaction_output_index
					}
				}
			}
		}

		let counterparty_claimable_outpoints_len: u64 = Readable::read(reader)?;
		let mut counterparty_claimable_outpoints = hash_map_with_capacity(cmp::min(counterparty_claimable_outpoints_len as usize, MAX_ALLOC_SIZE / 64));
		for _ in 0..counterparty_claimable_outpoints_len {
			let txid: Txid = Readable::read(reader)?;
			let htlcs_count: u64 = Readable::read(reader)?;
			let mut htlcs = Vec::with_capacity(cmp::min(htlcs_count as usize, MAX_ALLOC_SIZE / 32));
			for _ in 0..htlcs_count {
				htlcs.push((read_htlc_in_commitment!(), <Option<HTLCSource> as Readable>::read(reader)?.map(|o: HTLCSource| Box::new(o))));
			}
			if counterparty_claimable_outpoints.insert(txid, htlcs).is_some() {
				return Err(DecodeError::InvalidValue);
			}
		}

		let counterparty_commitment_txn_on_chain_len: u64 = Readable::read(reader)?;
		let mut counterparty_commitment_txn_on_chain = hash_map_with_capacity(cmp::min(counterparty_commitment_txn_on_chain_len as usize, MAX_ALLOC_SIZE / 32));
		for _ in 0..counterparty_commitment_txn_on_chain_len {
			let txid: Txid = Readable::read(reader)?;
			let commitment_number = <U48 as Readable>::read(reader)?.0;
			if counterparty_commitment_txn_on_chain.insert(txid, commitment_number).is_some() {
				return Err(DecodeError::InvalidValue);
			}
		}

		let counterparty_hash_commitment_number_len: u64 = Readable::read(reader)?;
		let mut counterparty_hash_commitment_number = hash_map_with_capacity(cmp::min(counterparty_hash_commitment_number_len as usize, MAX_ALLOC_SIZE / 32));
		for _ in 0..counterparty_hash_commitment_number_len {
			let payment_hash: PaymentHash = Readable::read(reader)?;
			let commitment_number = <U48 as Readable>::read(reader)?.0;
			if counterparty_hash_commitment_number.insert(payment_hash, commitment_number).is_some() {
				return Err(DecodeError::InvalidValue);
			}
		}

		let prev_holder_signed_tx: Option<HolderSignedTx> =
			match <u8 as Readable>::read(reader)? {
				0 => None,
				1 => Some(Readable::read(reader)?),
				_ => return Err(DecodeError::InvalidValue),
			};
		let current_holder_signed_tx: HolderSignedTx = Readable::read(reader)?;

		let current_counterparty_commitment_number = <U48 as Readable>::read(reader)?.0;
		let current_holder_commitment_number = <U48 as Readable>::read(reader)?.0;

		let payment_preimages_len: u64 = Readable::read(reader)?;
		let mut payment_preimages = hash_map_with_capacity(cmp::min(payment_preimages_len as usize, MAX_ALLOC_SIZE / 32));
		for _ in 0..payment_preimages_len {
			let preimage: PaymentPreimage = Readable::read(reader)?;
			let hash = PaymentHash(Sha256::hash(&preimage.0[..]).to_byte_array());
			if payment_preimages.insert(hash, (preimage, Vec::new())).is_some() {
				return Err(DecodeError::InvalidValue);
			}
		}

		let pending_monitor_events_len: u64 = Readable::read(reader)?;
		let mut pending_monitor_events = Some(
			Vec::with_capacity(cmp::min(pending_monitor_events_len as usize, MAX_ALLOC_SIZE / (32 + 8*3))));
		for _ in 0..pending_monitor_events_len {
			let ev = match <u8 as Readable>::read(reader)? {
				0 => MonitorEvent::HTLCEvent(Readable::read(reader)?),
				1 => MonitorEvent::HolderForceClosed(outpoint),
				_ => return Err(DecodeError::InvalidValue)
			};
			pending_monitor_events.as_mut().unwrap().push(ev);
		}

		let pending_events_len: u64 = Readable::read(reader)?;
		let mut pending_events = Vec::with_capacity(cmp::min(pending_events_len as usize, MAX_ALLOC_SIZE / mem::size_of::<Event>()));
		for _ in 0..pending_events_len {
			if let Some(event) = MaybeReadable::read(reader)? {
				pending_events.push(event);
			}
		}

		let best_block = BestBlock::new(Readable::read(reader)?, Readable::read(reader)?);

		let waiting_threshold_conf_len: u64 = Readable::read(reader)?;
		let mut onchain_events_awaiting_threshold_conf = Vec::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
		for _ in 0..waiting_threshold_conf_len {
			if let Some(val) = MaybeReadable::read(reader)? {
				onchain_events_awaiting_threshold_conf.push(val);
			}
		}

		let outputs_to_watch_len: u64 = Readable::read(reader)?;
		let mut outputs_to_watch = hash_map_with_capacity(cmp::min(outputs_to_watch_len as usize, MAX_ALLOC_SIZE / (mem::size_of::<Txid>() + mem::size_of::<u32>() + mem::size_of::<Vec<ScriptBuf>>())));
		for _ in 0..outputs_to_watch_len {
			let txid = Readable::read(reader)?;
			let outputs_len: u64 = Readable::read(reader)?;
			let mut outputs = Vec::with_capacity(cmp::min(outputs_len as usize, MAX_ALLOC_SIZE / (mem::size_of::<u32>() + mem::size_of::<ScriptBuf>())));
			for _ in 0..outputs_len {
				outputs.push((Readable::read(reader)?, Readable::read(reader)?));
			}
			if outputs_to_watch.insert(txid, outputs).is_some() {
				return Err(DecodeError::InvalidValue);
			}
		}
		let mut onchain_tx_handler: OnchainTxHandler<SP::EcdsaSigner> = ReadableArgs::read(
			reader, (entropy_source, signer_provider, channel_value_satoshis, channel_keys_id)
		)?;

		let lockdown_from_offchain = Readable::read(reader)?;
		let holder_tx_signed = Readable::read(reader)?;

		let mut funding_spend_confirmed = None;
		let mut htlcs_resolved_on_chain = Some(Vec::new());
		let mut htlcs_resolved_to_user = Some(new_hash_set());
		let mut funding_spend_seen = Some(false);
		let mut counterparty_node_id = None;
		let mut confirmed_commitment_tx_counterparty_output = None;
		let mut spendable_txids_confirmed = Some(Vec::new());
		let mut counterparty_fulfilled_htlcs = Some(new_hash_map());
		let mut initial_counterparty_commitment_info = None;
		let mut initial_counterparty_commitment_tx = None;
		let mut balances_empty_height = None;
		let mut channel_id = None;
		let mut holder_pays_commitment_tx_fee = None;
		let mut payment_preimages_with_info: Option<HashMap<_, _>> = None;
		let mut first_negotiated_funding_txo = RequiredWrapper(None);
		let mut channel_parameters = None;
		let mut pending_funding = None;
		let mut alternative_funding_confirmed = None;
		let mut is_manual_broadcast = RequiredWrapper(None);
		let mut funding_seen_onchain = RequiredWrapper(None);
		read_tlv_fields!(reader, {
			(1, funding_spend_confirmed, option),
			(3, htlcs_resolved_on_chain, optional_vec),
			(5, pending_monitor_events, optional_vec),
			(7, funding_spend_seen, option),
			(9, counterparty_node_id, option),
			(11, confirmed_commitment_tx_counterparty_output, option),
			(13, spendable_txids_confirmed, optional_vec),
			(15, counterparty_fulfilled_htlcs, option),
			(17, initial_counterparty_commitment_info, option),
			(19, channel_id, option),
			(21, balances_empty_height, option),
			(23, holder_pays_commitment_tx_fee, option),
			(25, payment_preimages_with_info, option),
			(27, first_negotiated_funding_txo, (default_value, outpoint)),
			(29, initial_counterparty_commitment_tx, option),
			(31, channel_parameters, (option: ReadableArgs, None)),
			(32, pending_funding, optional_vec),
			(33, htlcs_resolved_to_user, option),
			(34, alternative_funding_confirmed, option),
			(35, is_manual_broadcast, (default_value, false)),
			(37, funding_seen_onchain, (default_value, true)),
		});
		// Note that `payment_preimages_with_info` was added (and is always written) in LDK 0.1, so
		// we can use it to determine if this monitor was last written by LDK 0.1 or later.
		let written_by_0_1_or_later = payment_preimages_with_info.is_some();
		if let Some(payment_preimages_with_info) = payment_preimages_with_info {
			if payment_preimages_with_info.len() != payment_preimages.len() {
				return Err(DecodeError::InvalidValue);
			}
			for (payment_hash, (payment_preimage, _)) in payment_preimages.iter() {
				// Note that because `payment_preimages` is built back from preimages directly,
				// checking that the two maps have the same hash -> preimage pairs also checks that
				// the payment hashes in `payment_preimages_with_info`'s preimages match its
				// hashes.
				let new_preimage = payment_preimages_with_info.get(payment_hash).map(|(p, _)| p);
				if new_preimage != Some(payment_preimage) {
					return Err(DecodeError::InvalidValue);
				}
			}
			payment_preimages = payment_preimages_with_info;
		}

		// `HolderForceClosedWithInfo` replaced `HolderForceClosed` in v0.0.122. If we have both
		// events, we can remove the `HolderForceClosed` event and just keep the `HolderForceClosedWithInfo`.
		if let Some(ref mut pending_monitor_events) = pending_monitor_events {
			if pending_monitor_events.iter().any(|e| matches!(e, MonitorEvent::HolderForceClosed(_))) &&
				pending_monitor_events.iter().any(|e| matches!(e, MonitorEvent::HolderForceClosedWithInfo { .. }))
			{
				pending_monitor_events.retain(|e| !matches!(e, MonitorEvent::HolderForceClosed(_)));
			}
		}

		let channel_parameters = channel_parameters.unwrap_or_else(|| {
			onchain_tx_handler.channel_parameters().clone()
		});

		// Monitors for anchor outputs channels opened in v0.0.116 suffered from a bug in which the
		// wrong `counterparty_payment_script` was being tracked. Fix it now on deserialization to
		// give them a chance to recognize the spendable output.
		if channel_parameters.channel_type_features.supports_anchors_zero_fee_htlc_tx() &&
			counterparty_payment_script.is_p2wpkh()
		{
			let payment_point = channel_parameters.holder_pubkeys.payment_point;
			counterparty_payment_script =
				chan_utils::get_to_countersigner_keyed_anchor_redeemscript(&payment_point).to_p2wsh();
		}

		let channel_id = channel_id.unwrap_or(ChannelId::v1_from_funding_outpoint(outpoint));
		onchain_tx_handler.set_channel_id(channel_id);

		let (current_holder_commitment_tx, current_holder_htlc_data) = {
			let holder_commitment_tx = onchain_tx_handler.current_holder_commitment_tx();

			#[cfg(debug_assertions)]
			let holder_signed_tx_copy = current_holder_signed_tx.clone();

			let holder_commitment_htlc_data = CommitmentHTLCData::try_from(current_holder_signed_tx)
				.map_err(|_| DecodeError::InvalidValue)?;

			#[cfg(debug_assertions)] {
				let mut stream = crate::util::ser::VecWriter(Vec::new());
				write_legacy_holder_commitment_data(
					&mut stream, &holder_commitment_tx, &holder_commitment_htlc_data
				).map_err(|_| DecodeError::InvalidValue)?;
				let mut cursor = crate::io::Cursor::new(stream.0);
				if holder_signed_tx_copy != <HolderSignedTx as Readable>::read(&mut cursor)? {
					return Err(DecodeError::InvalidValue);
				}
			}

			(holder_commitment_tx.clone(), holder_commitment_htlc_data)
		};

		let (prev_holder_commitment_tx, prev_holder_htlc_data) =
			if let Some(prev_holder_signed_tx) = prev_holder_signed_tx {
				let holder_commitment_tx = onchain_tx_handler.prev_holder_commitment_tx();
				if holder_commitment_tx.is_none() {
					return Err(DecodeError::InvalidValue);
				}

				#[cfg(debug_assertions)]
				let holder_signed_tx_copy = prev_holder_signed_tx.clone();

				let holder_commitment_htlc_data = CommitmentHTLCData::try_from(prev_holder_signed_tx)
					.map_err(|_| DecodeError::InvalidValue)?;

				#[cfg(debug_assertions)] {
					let mut stream = crate::util::ser::VecWriter(Vec::new());
					write_legacy_holder_commitment_data(
						&mut stream, &holder_commitment_tx.unwrap(), &holder_commitment_htlc_data
					).map_err(|_| DecodeError::InvalidValue)?;
					let mut cursor = crate::io::Cursor::new(stream.0);
					if holder_signed_tx_copy != <HolderSignedTx as Readable>::read(&mut cursor)? {
						return Err(DecodeError::InvalidValue);
					}
				}

				(holder_commitment_tx.cloned(), Some(holder_commitment_htlc_data))
			} else {
				(None, None)
			};

		let dummy_node_id = PublicKey::from_slice(&[2; 33]).unwrap();
		onchain_tx_handler
			.set_counterparty_node_id(counterparty_node_id.unwrap_or(dummy_node_id));
		let monitor = ChannelMonitor::from_impl(ChannelMonitorImpl {
			funding: FundingScope {
				channel_parameters,

				current_counterparty_commitment_txid,
				prev_counterparty_commitment_txid,
				counterparty_claimable_outpoints,

				current_holder_commitment_tx,
				prev_holder_commitment_tx,
			},
			pending_funding: pending_funding.unwrap_or(vec![]),
			is_manual_broadcast: is_manual_broadcast.0.unwrap(),
			// Older monitors prior to LDK 0.2 assume this is `true` when absent
			// during upgrade so holder broadcasts aren't gated unexpectedly.
			funding_seen_onchain: funding_seen_onchain.0.unwrap(),

			latest_update_id,
			commitment_transaction_number_obscure_factor,

			destination_script,
			broadcasted_holder_revokable_script,
			counterparty_payment_script,
			shutdown_script,

			channel_keys_id,
			holder_revocation_basepoint,
			channel_id,
			first_negotiated_funding_txo: first_negotiated_funding_txo.0.unwrap(),

			counterparty_commitment_params,
			their_cur_per_commitment_points,

			on_holder_tx_csv,

			commitment_secrets,
			counterparty_commitment_txn_on_chain,
			counterparty_hash_commitment_number,
			counterparty_fulfilled_htlcs: counterparty_fulfilled_htlcs.unwrap(),

			current_counterparty_commitment_number,
			current_holder_commitment_number,

			payment_preimages,
			pending_monitor_events: pending_monitor_events.unwrap(),
			pending_events,
			is_processing_pending_events: false,

			onchain_events_awaiting_threshold_conf,
			outputs_to_watch,

			onchain_tx_handler,

			lockdown_from_offchain,
			holder_tx_signed,
			holder_pays_commitment_tx_fee,
			funding_spend_seen: funding_spend_seen.unwrap(),
			funding_spend_confirmed,
			confirmed_commitment_tx_counterparty_output,
			htlcs_resolved_on_chain: htlcs_resolved_on_chain.unwrap(),
			htlcs_resolved_to_user: htlcs_resolved_to_user.unwrap(),
			spendable_txids_confirmed: spendable_txids_confirmed.unwrap(),

			best_block,
			counterparty_node_id: counterparty_node_id.unwrap_or(dummy_node_id),
			initial_counterparty_commitment_info,
			initial_counterparty_commitment_tx,
			balances_empty_height,
			failed_back_htlc_ids: new_hash_set(),

			current_holder_htlc_data,
			prev_holder_htlc_data,

			alternative_funding_confirmed,

			written_by_0_1_or_later,
		});

		if counterparty_node_id.is_none() {
			if (holder_tx_signed || lockdown_from_offchain) && monitor.get_claimable_balances().is_empty() {
				// If the monitor is no longer readable, but it is a candidate for archiving,
				// return Ok(None) to allow it to be skipped and not loaded.
				return Ok(None);
			} else {
				panic!("Found monitor for channel {channel_id} with no updates since v0.0.118. \
					These monitors are no longer supported. \
					To continue, run a v0.1 release, send/route a payment over the channel or close it.");
			}
		}
		Ok(Some((best_block.block_hash, monitor)))
	}
}

#[cfg(test)]
mod tests {
	use bitcoin::amount::Amount;
	use bitcoin::hash_types::{BlockHash, Txid};
	use bitcoin::hashes::sha256::Hash as Sha256;
	use bitcoin::hashes::Hash;
	use bitcoin::hex::FromHex;
	use bitcoin::locktime::absolute::LockTime;
	use bitcoin::network::Network;
	use bitcoin::opcodes;
	use bitcoin::script::{Builder, ScriptBuf};
	use bitcoin::secp256k1::Secp256k1;
	use bitcoin::secp256k1::{PublicKey, SecretKey};
	use bitcoin::sighash;
	use bitcoin::sighash::EcdsaSighashType;
	use bitcoin::transaction::OutPoint as BitcoinOutPoint;
	use bitcoin::transaction::{Transaction, TxIn, TxOut, Version};
	use bitcoin::{Sequence, Witness};

	use crate::chain::chaininterface::LowerBoundedFeeEstimator;
	use crate::events::ClosureReason;

	use super::ChannelMonitorUpdateStep;
	use crate::chain::channelmonitor::{ChannelMonitor, WithChannelMonitor};
	use crate::chain::package::{
		weight_offered_htlc, weight_received_htlc, weight_revoked_offered_htlc,
		weight_revoked_received_htlc, WEIGHT_REVOKED_OUTPUT,
	};
	use crate::chain::transaction::OutPoint;
	use crate::chain::{BestBlock, Confirm};
	use crate::io;
	use crate::ln::chan_utils::{
		self, ChannelPublicKeys, ChannelTransactionParameters,
		CounterpartyChannelTransactionParameters, HTLCOutputInCommitment,
		HolderCommitmentTransaction,
	};
	use crate::ln::channel_keys::{
		DelayedPaymentBasepoint, DelayedPaymentKey, HtlcBasepoint, RevocationBasepoint,
		RevocationKey,
	};
	use crate::ln::channelmanager::{HTLCSource, PaymentId};
	use crate::ln::functional_test_utils::*;
	use crate::ln::outbound_payment::RecipientOnionFields;
	use crate::ln::script::ShutdownScript;
	use crate::ln::types::ChannelId;
	use crate::sign::{ChannelSigner, InMemorySigner};
	use crate::sync::Arc;
	use crate::types::features::ChannelTypeFeatures;
	use crate::types::payment::{PaymentHash, PaymentPreimage};
	use crate::util::logger::Logger;
	use crate::util::ser::{ReadableArgs, Writeable};
	use crate::util::test_utils::{TestBroadcaster, TestFeeEstimator, TestLogger};
	use crate::{check_spends, get_local_commitment_txn, get_monitor, get_route_and_payment_hash};

	#[allow(unused_imports)]
	use crate::prelude::*;

	use std::str::FromStr;

	#[rustfmt::skip]
	fn do_test_funding_spend_refuses_updates(use_local_txn: bool) {
		// Previously, monitor updates were allowed freely even after a funding-spend transaction
		// confirmed. This would allow a race condition where we could receive a payment (including
		// the counterparty revoking their broadcasted state!) and accept it without recourse as
		// long as the ChannelMonitor receives the block first, the full commitment update dance
		// occurs after the block is connected, and before the ChannelManager receives the block.
		// Obviously this is an incredibly contrived race given the counterparty would be risking
		// their full channel balance for it, but its worth fixing nonetheless as it makes the
		// potential ChannelMonitor states simpler to reason about.
		//
		// This test checks said behavior, as well as ensuring a ChannelMonitorUpdate with multiple
		// updates is handled correctly in such conditions.
		let chanmon_cfgs = create_chanmon_cfgs(3);
		let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
		let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
		let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
		let channel = create_announced_chan_between_nodes(&nodes, 0, 1);
		create_announced_chan_between_nodes(&nodes, 1, 2);

		// Rebalance somewhat
		send_payment(&nodes[0], &[&nodes[1]], 10_000_000);

		// First route two payments for testing at the end
		let payment_preimage_1 = route_payment(&nodes[0], &[&nodes[1], &nodes[2]], 1_000_000).0;
		let payment_preimage_2 = route_payment(&nodes[0], &[&nodes[1], &nodes[2]], 1_000_000).0;

		let local_txn = get_local_commitment_txn!(nodes[1], channel.2);
		assert_eq!(local_txn.len(), 1);
		let remote_txn = get_local_commitment_txn!(nodes[0], channel.2);
		assert_eq!(remote_txn.len(), 3); // Commitment and two HTLC-Timeouts
		check_spends!(remote_txn[1], remote_txn[0]);
		check_spends!(remote_txn[2], remote_txn[0]);
		let broadcast_tx = if use_local_txn { &local_txn[0] } else { &remote_txn[0] };

		// Connect a commitment transaction, but only to the ChainMonitor/ChannelMonitor. The
		// channel is now closed, but the ChannelManager doesn't know that yet.
		let new_header = create_dummy_header(nodes[0].best_block_info().0, 0);
		let conf_height = nodes[0].best_block_info().1 + 1;
		nodes[1].chain_monitor.chain_monitor.transactions_confirmed(&new_header,
			&[(0, broadcast_tx)], conf_height);

		let (_, pre_update_monitor) = <(BlockHash, ChannelMonitor<_>)>::read(
						&mut io::Cursor::new(&get_monitor!(nodes[1], channel.2).encode()),
						(&nodes[1].keys_manager.backing, &nodes[1].keys_manager.backing)).unwrap();

		// If the ChannelManager tries to update the channel, however, the ChainMonitor will pass
		// the update through to the ChannelMonitor which will refuse it (as the channel is closed).
		let (route, payment_hash, _, payment_secret) = get_route_and_payment_hash!(nodes[1], nodes[0], 100_000);
		nodes[1].node.send_payment_with_route(route, payment_hash,
			RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)
		).unwrap();
		check_added_monitors(&nodes[1], 1);

		// Build a new ChannelMonitorUpdate which contains both the failing commitment tx update
		// and provides the claim preimages for the two pending HTLCs. The first update generates
		// an error, but the point of this test is to ensure the later updates are still applied.
		let replay_update = {
			let monitor_updates = nodes[1].chain_monitor.monitor_updates.lock().unwrap();
			let mut replay_update = monitor_updates.get(&channel.2).unwrap().iter().next_back().unwrap().clone();
			assert_eq!(replay_update.updates.len(), 1);
			if let ChannelMonitorUpdateStep::LatestCounterpartyCommitmentTXInfo { .. } = replay_update.updates[0] {
			} else { panic!(); }
			replay_update.updates.push(ChannelMonitorUpdateStep::PaymentPreimage {
				payment_preimage: payment_preimage_1, payment_info: None,
			});
			replay_update.updates.push(ChannelMonitorUpdateStep::PaymentPreimage {
				payment_preimage: payment_preimage_2, payment_info: None,
			});
			replay_update
		};

		let broadcaster = TestBroadcaster::with_blocks(Arc::clone(&nodes[1].blocks));
		assert!(
			pre_update_monitor.update_monitor(&replay_update, &&broadcaster, &&chanmon_cfgs[1].fee_estimator, &nodes[1].logger)
			.is_err());

		// Even though we error'd on the first update, we should still have generated an HTLC claim
		// transaction
		let txn_broadcasted = broadcaster.txn_broadcasted.lock().unwrap().split_off(0);
		assert!(txn_broadcasted.len() >= 2);
		let htlc_txn = txn_broadcasted.iter().filter(|tx| {
			assert_eq!(tx.input.len(), 1);
			tx.input[0].previous_output.txid == broadcast_tx.compute_txid()
		}).collect::<Vec<_>>();
		assert_eq!(htlc_txn.len(), 2);
		check_spends!(htlc_txn[0], broadcast_tx);
		check_spends!(htlc_txn[1], broadcast_tx);

		check_closed_broadcast(&nodes[1], 1, true);
		check_closed_event(&nodes[1], 1, ClosureReason::CommitmentTxConfirmed, &[nodes[0].node.get_our_node_id()], 100000);
		check_added_monitors(&nodes[1], 1);
	}

	#[test]
	fn test_funding_spend_refuses_updates() {
		do_test_funding_spend_refuses_updates(true);
		do_test_funding_spend_refuses_updates(false);
	}

	#[test]
	#[rustfmt::skip]
	fn test_prune_preimages() {
		let secp_ctx = Secp256k1::new();
		let logger = Arc::new(TestLogger::new());
		let broadcaster = Arc::new(TestBroadcaster::new(Network::Testnet));
		let fee_estimator = TestFeeEstimator::new(253);

		let dummy_key = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());

		let mut preimages = Vec::new();
		{
			for i in 0..20 {
				let preimage = PaymentPreimage([i; 32]);
				let hash = PaymentHash(Sha256::hash(&preimage.0[..]).to_byte_array());
				preimages.push((preimage, hash));
			}
		}

		let dummy_source = HTLCSource::dummy();

		macro_rules! preimages_slice_to_htlcs {
			($preimages_slice: expr) => {
				{
					let mut res = Vec::new();
					for (idx, preimage) in $preimages_slice.iter().enumerate() {
						res.push(HTLCOutputInCommitment {
							offered: true,
							amount_msat: 0,
							cltv_expiry: 0,
							payment_hash: preimage.1.clone(),
							transaction_output_index: Some(idx as u32),
						});
					}
					res
				}
			}
		}
		macro_rules! preimages_slice_to_htlc_outputs {
			($preimages_slice: expr) => {
				preimages_slice_to_htlcs!($preimages_slice).into_iter().map(|htlc| (htlc, None)).collect()
			}
		}
		let dummy_sig = crate::crypto::utils::sign(&secp_ctx,
			&bitcoin::secp256k1::Message::from_digest([42; 32]),
			&SecretKey::from_slice(&[42; 32]).unwrap());

		macro_rules! test_preimages_exist {
			($preimages_slice: expr, $monitor: expr) => {
				for preimage in $preimages_slice {
					assert!($monitor.inner.lock().unwrap().payment_preimages.contains_key(&preimage.1));
				}
			}
		}

		let keys = InMemorySigner::new(
			SecretKey::from_slice(&[41; 32]).unwrap(),
			SecretKey::from_slice(&[41; 32]).unwrap(),
			SecretKey::from_slice(&[41; 32]).unwrap(),
			SecretKey::from_slice(&[41; 32]).unwrap(),
			true,
			SecretKey::from_slice(&[41; 32]).unwrap(),
			SecretKey::from_slice(&[41; 32]).unwrap(),
			[41; 32],
			[0; 32],
			[0; 32],
		);

		let counterparty_pubkeys = ChannelPublicKeys {
			funding_pubkey: PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[44; 32]).unwrap()),
			revocation_basepoint: RevocationBasepoint::from(PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[45; 32]).unwrap())),
			payment_point: PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[46; 32]).unwrap()),
			delayed_payment_basepoint: DelayedPaymentBasepoint::from(PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[47; 32]).unwrap())),
			htlc_basepoint: HtlcBasepoint::from(PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[48; 32]).unwrap()))
		};
		let funding_outpoint = OutPoint { txid: Txid::all_zeros(), index: u16::MAX };
		let channel_id = ChannelId::v1_from_funding_outpoint(funding_outpoint);
		let channel_parameters = ChannelTransactionParameters {
			holder_pubkeys: keys.pubkeys(&secp_ctx),
			holder_selected_contest_delay: 66,
			is_outbound_from_holder: true,
			counterparty_parameters: Some(CounterpartyChannelTransactionParameters {
				pubkeys: counterparty_pubkeys,
				selected_contest_delay: 67,
			}),
			funding_outpoint: Some(funding_outpoint),
			splice_parent_funding_txid: None,
			channel_type_features: ChannelTypeFeatures::only_static_remote_key(),
			channel_value_satoshis: 0,
		};
		// Prune with one old state and a holder commitment tx holding a few overlaps with the
		// old state.
		let shutdown_pubkey = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
		let shutdown_script = ShutdownScript::new_p2wpkh_from_pubkey(shutdown_pubkey);
		let best_block = BestBlock::from_network(Network::Testnet);
		let monitor = ChannelMonitor::new(
			Secp256k1::new(), keys, Some(shutdown_script.into_inner()), 0, &ScriptBuf::new(),
			&channel_parameters, true, 0, HolderCommitmentTransaction::dummy(0, funding_outpoint, Vec::new()),
			best_block, dummy_key, channel_id, false,
		);

		let nondust_htlcs = preimages_slice_to_htlcs!(preimages[0..10]);
		let dummy_commitment_tx = HolderCommitmentTransaction::dummy(0, funding_outpoint, nondust_htlcs);
		// These HTLCs now have their output indices assigned
		let nondust_htlcs = dummy_commitment_tx.nondust_htlcs();

		monitor.provide_latest_holder_commitment_tx(dummy_commitment_tx.clone(),
			&nondust_htlcs.iter().map(|htlc| (htlc.clone(), Some(dummy_sig), Some(dummy_source.clone()))).collect::<Vec<_>>());
		monitor.provide_latest_counterparty_commitment_tx(Txid::from_byte_array(Sha256::hash(b"1").to_byte_array()),
			preimages_slice_to_htlc_outputs!(preimages[5..15]), 281474976710655, dummy_key);
		monitor.provide_latest_counterparty_commitment_tx(Txid::from_byte_array(Sha256::hash(b"2").to_byte_array()),
			preimages_slice_to_htlc_outputs!(preimages[15..20]), 281474976710654, dummy_key);
		for &(ref preimage, ref hash) in preimages.iter() {
			let bounded_fee_estimator = LowerBoundedFeeEstimator::new(&fee_estimator);
			monitor.provide_payment_preimage_unsafe_legacy(
				hash, preimage, &broadcaster, &bounded_fee_estimator, &logger
			);
		}

		// Now provide a secret, pruning preimages 10-15
		let mut secret = [0; 32];
		secret[0..32].clone_from_slice(&<Vec<u8>>::from_hex("7cc854b54e3e0dcdb010d7a3fee464a9687be6e8db3be6854c475621e007a5dc").unwrap());
		monitor.provide_secret(281474976710655, secret.clone()).unwrap();
		assert_eq!(monitor.inner.lock().unwrap().payment_preimages.len(), 15);
		test_preimages_exist!(&preimages[0..10], monitor);
		test_preimages_exist!(&preimages[15..20], monitor);

		monitor.provide_latest_counterparty_commitment_tx(Txid::from_byte_array(Sha256::hash(b"3").to_byte_array()),
			preimages_slice_to_htlc_outputs!(preimages[17..20]), 281474976710653, dummy_key);

		// Now provide a further secret, pruning preimages 15-17
		secret[0..32].clone_from_slice(&<Vec<u8>>::from_hex("c7518c8ae4660ed02894df8976fa1a3659c1a8b4b5bec0c4b872abeba4cb8964").unwrap());
		monitor.provide_secret(281474976710654, secret.clone()).unwrap();
		assert_eq!(monitor.inner.lock().unwrap().payment_preimages.len(), 13);
		test_preimages_exist!(&preimages[0..10], monitor);
		test_preimages_exist!(&preimages[17..20], monitor);

		monitor.provide_latest_counterparty_commitment_tx(Txid::from_byte_array(Sha256::hash(b"4").to_byte_array()),
			preimages_slice_to_htlc_outputs!(preimages[18..20]), 281474976710652, dummy_key);

		// Now update holder commitment tx info, pruning only element 18 as we still care about the
		// previous commitment tx's preimages too
		let nondust_htlcs = preimages_slice_to_htlcs!(preimages[0..5]);
		let dummy_commitment_tx = HolderCommitmentTransaction::dummy(0, funding_outpoint, nondust_htlcs);
		// These HTLCs now have their output indices assigned
		let nondust_htlcs = dummy_commitment_tx.nondust_htlcs();
		monitor.provide_latest_holder_commitment_tx(dummy_commitment_tx.clone(),
			&nondust_htlcs.iter().map(|htlc| (htlc.clone(), Some(dummy_sig), Some(dummy_source.clone()))).collect::<Vec<_>>());
		secret[0..32].clone_from_slice(&<Vec<u8>>::from_hex("2273e227a5b7449b6e70f1fb4652864038b1cbf9cd7c043a7d6456b7fc275ad8").unwrap());
		monitor.provide_secret(281474976710653, secret.clone()).unwrap();
		assert_eq!(monitor.inner.lock().unwrap().payment_preimages.len(), 12);
		test_preimages_exist!(&preimages[0..10], monitor);
		test_preimages_exist!(&preimages[18..20], monitor);

		// But if we do it again, we'll prune 5-10
		let nondust_htlcs = preimages_slice_to_htlcs!(preimages[0..3]);
		let dummy_commitment_tx = HolderCommitmentTransaction::dummy(0, funding_outpoint, nondust_htlcs);
		// These HTLCs now have their output indices assigned
		let nondust_htlcs = dummy_commitment_tx.nondust_htlcs();
		monitor.provide_latest_holder_commitment_tx(dummy_commitment_tx.clone(),
			&nondust_htlcs.iter().map(|htlc| (htlc.clone(), Some(dummy_sig), Some(dummy_source.clone()))).collect::<Vec<_>>());
		secret[0..32].clone_from_slice(&<Vec<u8>>::from_hex("27cddaa5624534cb6cb9d7da077cf2b22ab21e9b506fd4998a51d54502e99116").unwrap());
		monitor.provide_secret(281474976710652, secret.clone()).unwrap();
		assert_eq!(monitor.inner.lock().unwrap().payment_preimages.len(), 5);
		test_preimages_exist!(&preimages[0..5], monitor);
	}

	#[test]
	#[rustfmt::skip]
	fn test_claim_txn_weight_computation() {
		// We test Claim txn weight, knowing that we want expected weigth and
		// not actual case to avoid sigs and time-lock delays hell variances.

		let secp_ctx = Secp256k1::new();
		let privkey = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
		let pubkey = PublicKey::from_secret_key(&secp_ctx, &privkey);

		use crate::ln::channel_keys::{HtlcKey, HtlcBasepoint};
		macro_rules! sign_input {
			($sighash_parts: expr, $idx: expr, $amount: expr, $weight: expr, $sum_actual_sigs: expr, $opt_anchors: expr) => {
				let htlc = HTLCOutputInCommitment {
					offered: if *$weight == weight_revoked_offered_htlc($opt_anchors) || *$weight == weight_offered_htlc($opt_anchors) { true } else { false },
					amount_msat: 0,
					cltv_expiry: 2 << 16,
					payment_hash: PaymentHash([1; 32]),
					transaction_output_index: Some($idx as u32),
				};
				let redeem_script = if *$weight == WEIGHT_REVOKED_OUTPUT { chan_utils::get_revokeable_redeemscript(&RevocationKey::from_basepoint(&secp_ctx, &RevocationBasepoint::from(pubkey), &pubkey), 256, &DelayedPaymentKey::from_basepoint(&secp_ctx, &DelayedPaymentBasepoint::from(pubkey), &pubkey)) } else { chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, $opt_anchors, &HtlcKey::from_basepoint(&secp_ctx, &HtlcBasepoint::from(pubkey), &pubkey), &HtlcKey::from_basepoint(&secp_ctx, &HtlcBasepoint::from(pubkey), &pubkey), &RevocationKey::from_basepoint(&secp_ctx, &RevocationBasepoint::from(pubkey), &pubkey)) };
				let sighash = hash_to_message!(&$sighash_parts.p2wsh_signature_hash($idx, &redeem_script, $amount, EcdsaSighashType::All).unwrap()[..]);
				let sig = secp_ctx.sign_ecdsa(&sighash, &privkey);
				let mut ser_sig = sig.serialize_der().to_vec();
				ser_sig.push(EcdsaSighashType::All as u8);
				$sum_actual_sigs += ser_sig.len() as u64;
				let witness = $sighash_parts.witness_mut($idx).unwrap();
				witness.push(ser_sig);
				if *$weight == WEIGHT_REVOKED_OUTPUT {
					witness.push(vec!(1));
				} else if *$weight == weight_revoked_offered_htlc($opt_anchors) || *$weight == weight_revoked_received_htlc($opt_anchors) {
					witness.push(pubkey.clone().serialize().to_vec());
				} else if *$weight == weight_received_htlc($opt_anchors) {
					witness.push(vec![0]);
				} else {
					witness.push(PaymentPreimage([1; 32]).0.to_vec());
				}
				witness.push(redeem_script.into_bytes());
				let witness = witness.to_vec();
				println!("witness[0] {}", witness[0].len());
				println!("witness[1] {}", witness[1].len());
				println!("witness[2] {}", witness[2].len());
			}
		}

		let script_pubkey = Builder::new().push_opcode(opcodes::all::OP_RETURN).into_script();
		let txid = Txid::from_str("56944c5d3f98413ef45cf54545538103cc9f298e0575820ad3591376e2e0f65d").unwrap();

		// Justice tx with 1 to_holder, 2 revoked offered HTLCs, 1 revoked received HTLCs
		for channel_type_features in [ChannelTypeFeatures::only_static_remote_key(), ChannelTypeFeatures::anchors_zero_htlc_fee_and_dependencies()].iter() {
			let mut claim_tx = Transaction { version: Version(0), lock_time: LockTime::ZERO, input: Vec::new(), output: Vec::new() };
			let mut sum_actual_sigs = 0;
			for i in 0..4 {
				claim_tx.input.push(TxIn {
					previous_output: BitcoinOutPoint {
						txid,
						vout: i,
					},
					script_sig: ScriptBuf::new(),
					sequence: Sequence::ENABLE_RBF_NO_LOCKTIME,
					witness: Witness::new(),
				});
			}
			claim_tx.output.push(TxOut {
				script_pubkey: script_pubkey.clone(),
				value: Amount::ZERO,
			});
			let base_weight = claim_tx.weight().to_wu();
			let inputs_weight = [WEIGHT_REVOKED_OUTPUT, weight_revoked_offered_htlc(channel_type_features), weight_revoked_offered_htlc(channel_type_features), weight_revoked_received_htlc(channel_type_features)];
			let mut inputs_total_weight = 2; // count segwit flags
			{
				let mut sighash_parts = sighash::SighashCache::new(&mut claim_tx);
				for (idx, inp) in inputs_weight.iter().enumerate() {
					sign_input!(sighash_parts, idx, Amount::ZERO, inp, sum_actual_sigs, channel_type_features);
					inputs_total_weight += inp;
				}
			}
			assert_eq!(base_weight + inputs_total_weight, claim_tx.weight().to_wu() + /* max_length_sig */ (73 * inputs_weight.len() as u64 - sum_actual_sigs));
		}

		// Claim tx with 1 offered HTLCs, 3 received HTLCs
		for channel_type_features in [ChannelTypeFeatures::only_static_remote_key(), ChannelTypeFeatures::anchors_zero_htlc_fee_and_dependencies()].iter() {
			let mut claim_tx = Transaction { version: Version(0), lock_time: LockTime::ZERO, input: Vec::new(), output: Vec::new() };
			let mut sum_actual_sigs = 0;
			for i in 0..4 {
				claim_tx.input.push(TxIn {
					previous_output: BitcoinOutPoint {
						txid,
						vout: i,
					},
					script_sig: ScriptBuf::new(),
					sequence: Sequence::ENABLE_RBF_NO_LOCKTIME,
					witness: Witness::new(),
				});
			}
			claim_tx.output.push(TxOut {
				script_pubkey: script_pubkey.clone(),
				value: Amount::ZERO,
			});
			let base_weight = claim_tx.weight().to_wu();
			let inputs_weight = [weight_offered_htlc(channel_type_features), weight_received_htlc(channel_type_features), weight_received_htlc(channel_type_features), weight_received_htlc(channel_type_features)];
			let mut inputs_total_weight = 2; // count segwit flags
			{
				let mut sighash_parts = sighash::SighashCache::new(&mut claim_tx);
				for (idx, inp) in inputs_weight.iter().enumerate() {
					sign_input!(sighash_parts, idx, Amount::ZERO, inp, sum_actual_sigs, channel_type_features);
					inputs_total_weight += inp;
				}
			}
			assert_eq!(base_weight + inputs_total_weight, claim_tx.weight().to_wu() + /* max_length_sig */ (73 * inputs_weight.len() as u64 - sum_actual_sigs));
		}

		// Justice tx with 1 revoked HTLC-Success tx output
		for channel_type_features in [ChannelTypeFeatures::only_static_remote_key(), ChannelTypeFeatures::anchors_zero_htlc_fee_and_dependencies()].iter() {
			let mut claim_tx = Transaction { version: Version(0), lock_time: LockTime::ZERO, input: Vec::new(), output: Vec::new() };
			let mut sum_actual_sigs = 0;
			claim_tx.input.push(TxIn {
				previous_output: BitcoinOutPoint {
					txid,
					vout: 0,
				},
				script_sig: ScriptBuf::new(),
				sequence: Sequence::ENABLE_RBF_NO_LOCKTIME,
				witness: Witness::new(),
			});
			claim_tx.output.push(TxOut {
				script_pubkey: script_pubkey.clone(),
				value: Amount::ZERO,
			});
			let base_weight = claim_tx.weight().to_wu();
			let inputs_weight = [WEIGHT_REVOKED_OUTPUT];
			let mut inputs_total_weight = 2; // count segwit flags
			{
				let mut sighash_parts = sighash::SighashCache::new(&mut claim_tx);
				for (idx, inp) in inputs_weight.iter().enumerate() {
					sign_input!(sighash_parts, idx, Amount::ZERO, inp, sum_actual_sigs, channel_type_features);
					inputs_total_weight += inp;
				}
			}
			assert_eq!(base_weight + inputs_total_weight, claim_tx.weight().to_wu() + /* max_length_isg */ (73 * inputs_weight.len() as u64 - sum_actual_sigs));
		}
	}

	#[test]
	#[rustfmt::skip]
	fn test_with_channel_monitor_impl_logger() {
		let secp_ctx = Secp256k1::new();
		let logger = Arc::new(TestLogger::new());

		let dummy_key = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());

		let keys = InMemorySigner::new(
			SecretKey::from_slice(&[41; 32]).unwrap(),
			SecretKey::from_slice(&[41; 32]).unwrap(),
			SecretKey::from_slice(&[41; 32]).unwrap(),
			SecretKey::from_slice(&[41; 32]).unwrap(),
			true,
			SecretKey::from_slice(&[41; 32]).unwrap(),
			SecretKey::from_slice(&[41; 32]).unwrap(),
			[41; 32],
			[0; 32],
			[0; 32],
		);

		let counterparty_pubkeys = ChannelPublicKeys {
			funding_pubkey: PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[44; 32]).unwrap()),
			revocation_basepoint: RevocationBasepoint::from(PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[45; 32]).unwrap())),
			payment_point: PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[46; 32]).unwrap()),
			delayed_payment_basepoint: DelayedPaymentBasepoint::from(PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[47; 32]).unwrap())),
			htlc_basepoint: HtlcBasepoint::from(PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[48; 32]).unwrap())),
		};
		let funding_outpoint = OutPoint { txid: Txid::all_zeros(), index: u16::MAX };
		let channel_id = ChannelId::v1_from_funding_outpoint(funding_outpoint);
		let channel_parameters = ChannelTransactionParameters {
			holder_pubkeys: keys.pubkeys(&secp_ctx),
			holder_selected_contest_delay: 66,
			is_outbound_from_holder: true,
			counterparty_parameters: Some(CounterpartyChannelTransactionParameters {
				pubkeys: counterparty_pubkeys,
				selected_contest_delay: 67,
			}),
			funding_outpoint: Some(funding_outpoint),
			splice_parent_funding_txid: None,
			channel_type_features: ChannelTypeFeatures::only_static_remote_key(),
			channel_value_satoshis: 0,
		};
		let shutdown_pubkey = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
		let shutdown_script = ShutdownScript::new_p2wpkh_from_pubkey(shutdown_pubkey);
		let best_block = BestBlock::from_network(Network::Testnet);
		let monitor = ChannelMonitor::new(
			Secp256k1::new(), keys, Some(shutdown_script.into_inner()), 0, &ScriptBuf::new(),
			&channel_parameters, true, 0, HolderCommitmentTransaction::dummy(0, funding_outpoint, Vec::new()),
			best_block, dummy_key, channel_id, false,
		);

		let chan_id = monitor.inner.lock().unwrap().channel_id();
		let payment_hash = PaymentHash([1; 32]);
		let context_logger = WithChannelMonitor::from(&logger, &monitor, Some(payment_hash));
		log_error!(context_logger, "This is an error");
		log_warn!(context_logger, "This is an error");
		log_debug!(context_logger, "This is an error");
		log_trace!(context_logger, "This is an error");
		log_gossip!(context_logger, "This is an error");
		log_info!(context_logger, "This is an error");
		logger.assert_log_context_contains("lightning::chain::channelmonitor::tests", Some(dummy_key), Some(chan_id), 6);
	}
	// Further testing is done in the ChannelManager integration tests.
}