mod.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.

//! Events are returned from various bits in the library which indicate some action must be taken
//! by the client.
//!
//! Because we don't have a built-in runtime, it's up to the client to call events at a time in the
//! future, as well as generate and broadcast funding transactions handle payment preimages and a
//! few other things.

pub mod bump_transaction;

pub use bump_transaction::BumpTransactionEvent;

use crate::blinded_path::message::OffersContext;
use crate::blinded_path::payment::{
	Bolt12OfferContext, Bolt12RefundContext, PaymentContext, PaymentContextRef,
};
use crate::chain::transaction;
use crate::ln::channel::FUNDING_CONF_DEADLINE_BLOCKS;
use crate::ln::channelmanager::{InterceptId, PaymentId, RecipientOnionFields};
use crate::ln::types::ChannelId;
use crate::ln::{msgs, LocalHTLCFailureReason};
use crate::offers::invoice::Bolt12Invoice;
use crate::offers::static_invoice::StaticInvoice;
use crate::onion_message::messenger::Responder;
use crate::routing::gossip::NetworkUpdate;
use crate::routing::router::{BlindedTail, Path, RouteHop, RouteParameters};
use crate::sign::SpendableOutputDescriptor;
use crate::types::features::ChannelTypeFeatures;
use crate::types::payment::{PaymentHash, PaymentPreimage, PaymentSecret};
use crate::types::string::UntrustedString;
use crate::util::errors::APIError;
use crate::util::ser::{
	BigSize, FixedLengthReader, MaybeReadable, Readable, RequiredWrapper, UpgradableRequired,
	WithoutLength, Writeable, Writer,
};

use crate::io;
use crate::sync::Arc;
use bitcoin::hashes::sha256::Hash as Sha256;
use bitcoin::hashes::Hash;
use bitcoin::script::ScriptBuf;
use bitcoin::secp256k1::PublicKey;
use bitcoin::{OutPoint, Transaction};
use core::ops::Deref;

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

/// `FundingInfo` holds information about a channel's funding transaction.
///
/// When LDK is set to manual propagation of the funding transaction
/// (via [`ChannelManager::unsafe_manual_funding_transaction_generated`),
/// LDK does not have the full transaction data. Instead, the `OutPoint`
/// for the funding is provided here.
///
/// [`ChannelManager::unsafe_manual_funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::unsafe_manual_funding_transaction_generated
#[derive(Debug, PartialEq, Eq, Clone)]
pub enum FundingInfo {
	/// The full funding `Transaction`.
	Tx {
		/// The funding transaction
		transaction: Transaction,
	},
	/// The `OutPoint` of the funding.
	OutPoint {
		/// The outpoint of the funding
		outpoint: transaction::OutPoint,
	},
}

impl_writeable_tlv_based_enum!(FundingInfo,
	(0, Tx) => {
		(0, transaction, required)
	},
	(1, OutPoint) => {
		(1, outpoint, required)
	}
);

/// Some information provided on receipt of payment depends on whether the payment received is a
/// spontaneous payment or a "conventional" lightning payment that's paying an invoice.
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum PaymentPurpose {
	/// A payment for a BOLT 11 invoice.
	Bolt11InvoicePayment {
		/// The preimage to the payment_hash, if the payment hash (and secret) were fetched via
		/// [`ChannelManager::create_inbound_payment`]. When handling [`Event::PaymentClaimable`],
		/// this can be passed directly to [`ChannelManager::claim_funds`] to claim the payment. No
		/// action is needed when seen in [`Event::PaymentClaimed`].
		///
		/// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
		/// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
		payment_preimage: Option<PaymentPreimage>,
		/// The "payment secret". This authenticates the sender to the recipient, preventing a
		/// number of deanonymization attacks during the routing process.
		/// It is provided here for your reference, however its accuracy is enforced directly by
		/// [`ChannelManager`] using the values you previously provided to
		/// [`ChannelManager::create_inbound_payment`] or
		/// [`ChannelManager::create_inbound_payment_for_hash`].
		///
		/// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
		/// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
		/// [`ChannelManager::create_inbound_payment_for_hash`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment_for_hash
		payment_secret: PaymentSecret,
	},
	/// A payment for a BOLT 12 [`Offer`].
	///
	/// [`Offer`]: crate::offers::offer::Offer
	Bolt12OfferPayment {
		/// The preimage to the payment hash. When handling [`Event::PaymentClaimable`], this can be
		/// passed directly to [`ChannelManager::claim_funds`], if provided. No action is needed
		/// when seen in [`Event::PaymentClaimed`].
		///
		/// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
		payment_preimage: Option<PaymentPreimage>,
		/// The secret used to authenticate the sender to the recipient, preventing a number of
		/// de-anonymization attacks while routing a payment.
		///
		/// See [`PaymentPurpose::Bolt11InvoicePayment::payment_secret`] for further details.
		payment_secret: PaymentSecret,
		/// The context of the payment such as information about the corresponding [`Offer`] and
		/// [`InvoiceRequest`].
		///
		/// This includes the Human Readable Name which the sender indicated they were paying to,
		/// for possible recipient disambiguation if you're using a single wildcard DNS entry to
		/// resolve to many recipients.
		///
		/// [`Offer`]: crate::offers::offer::Offer
		/// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
		payment_context: Bolt12OfferContext,
	},
	/// A payment for a BOLT 12 [`Refund`].
	///
	/// [`Refund`]: crate::offers::refund::Refund
	Bolt12RefundPayment {
		/// The preimage to the payment hash. When handling [`Event::PaymentClaimable`], this can be
		/// passed directly to [`ChannelManager::claim_funds`], if provided. No action is needed
		/// when seen in [`Event::PaymentClaimed`].
		///
		/// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
		payment_preimage: Option<PaymentPreimage>,
		/// The secret used to authenticate the sender to the recipient, preventing a number of
		/// de-anonymization attacks while routing a payment.
		///
		/// See [`PaymentPurpose::Bolt11InvoicePayment::payment_secret`] for further details.
		payment_secret: PaymentSecret,
		/// The context of the payment such as information about the corresponding [`Refund`].
		///
		/// [`Refund`]: crate::offers::refund::Refund
		payment_context: Bolt12RefundContext,
	},
	/// Because this is a spontaneous payment, the payer generated their own preimage rather than us
	/// (the payee) providing a preimage.
	SpontaneousPayment(PaymentPreimage),
}

impl PaymentPurpose {
	/// Returns the preimage for this payment, if it is known.
	pub fn preimage(&self) -> Option<PaymentPreimage> {
		match self {
			PaymentPurpose::Bolt11InvoicePayment { payment_preimage, .. } => *payment_preimage,
			PaymentPurpose::Bolt12OfferPayment { payment_preimage, .. } => *payment_preimage,
			PaymentPurpose::Bolt12RefundPayment { payment_preimage, .. } => *payment_preimage,
			PaymentPurpose::SpontaneousPayment(preimage) => Some(*preimage),
		}
	}

	pub(crate) fn is_keysend(&self) -> bool {
		match self {
			PaymentPurpose::Bolt11InvoicePayment { .. } => false,
			PaymentPurpose::Bolt12OfferPayment { .. } => false,
			PaymentPurpose::Bolt12RefundPayment { .. } => false,
			PaymentPurpose::SpontaneousPayment(..) => true,
		}
	}

	/// Errors when provided an `AsyncBolt12OfferContext`, see below.
	pub(crate) fn from_parts(
		payment_preimage: Option<PaymentPreimage>, payment_secret: PaymentSecret,
		payment_context: Option<PaymentContext>,
	) -> Result<Self, ()> {
		match payment_context {
			None => Ok(PaymentPurpose::Bolt11InvoicePayment { payment_preimage, payment_secret }),
			Some(PaymentContext::Bolt12Offer(context)) => Ok(PaymentPurpose::Bolt12OfferPayment {
				payment_preimage,
				payment_secret,
				payment_context: context,
			}),
			Some(PaymentContext::Bolt12Refund(context)) => {
				Ok(PaymentPurpose::Bolt12RefundPayment {
					payment_preimage,
					payment_secret,
					payment_context: context,
				})
			},
			Some(PaymentContext::AsyncBolt12Offer(_)) => {
				// Callers are expected to convert from `AsyncBolt12OfferContext` to `Bolt12OfferContext`
				// using the invoice request provided in the payment onion prior to calling this method.
				debug_assert!(false);
				Err(())
			},
		}
	}
}

impl_writeable_tlv_based_enum_legacy!(PaymentPurpose,
	(0, Bolt11InvoicePayment) => {
		(0, payment_preimage, option),
		(2, payment_secret, required),
	},
	(4, Bolt12OfferPayment) => {
		(0, payment_preimage, option),
		(2, payment_secret, required),
		(4, payment_context, required),
	},
	(6, Bolt12RefundPayment) => {
		(0, payment_preimage, option),
		(2, payment_secret, required),
		(4, payment_context, required),
	},
	;
	(2, SpontaneousPayment)
);

/// Information about an HTLC that is part of a payment that can be claimed.
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct ClaimedHTLC {
	/// The counterparty of the channel.
	///
	/// This value will always be `None` for objects serialized with LDK versions prior to 0.2 and
	/// `Some` otherwise.
	pub counterparty_node_id: Option<PublicKey>,
	/// The `channel_id` of the channel over which the HTLC was received.
	pub channel_id: ChannelId,
	/// The `user_channel_id` of the channel over which the HTLC was received. This is the value
	/// passed in to [`ChannelManager::create_channel`] for outbound channels, or to
	/// [`ChannelManager::accept_inbound_channel`] for inbound channels if
	/// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true. Otherwise
	/// `user_channel_id` will be randomized for an inbound channel.
	///
	/// This field will be zero for a payment that was serialized prior to LDK version 0.0.117. (This
	/// should only happen in the case that a payment was claimable prior to LDK version 0.0.117, but
	/// was not actually claimed until after upgrading.)
	///
	/// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
	/// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
	/// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
	pub user_channel_id: u128,
	/// The block height at which this HTLC expires.
	pub cltv_expiry: u32,
	/// The amount (in msats) of this part of an MPP.
	pub value_msat: u64,
	/// The extra fee our counterparty skimmed off the top of this HTLC, if any.
	///
	/// This value will always be 0 for [`ClaimedHTLC`]s serialized with LDK versions prior to
	/// 0.0.119.
	pub counterparty_skimmed_fee_msat: u64,
}
impl_writeable_tlv_based!(ClaimedHTLC, {
	(0, channel_id, required),
	(1, counterparty_skimmed_fee_msat, (default_value, 0u64)),
	(2, user_channel_id, required),
	(3, counterparty_node_id, option),
	(4, cltv_expiry, required),
	(6, value_msat, required),
});

/// When the payment path failure took place and extra details about it. [`PathFailure::OnPath`] may
/// contain a [`NetworkUpdate`] that needs to be applied to the [`NetworkGraph`].
///
/// [`NetworkUpdate`]: crate::routing::gossip::NetworkUpdate
/// [`NetworkGraph`]: crate::routing::gossip::NetworkGraph
#[derive(Clone, Debug, Eq, PartialEq)]
pub enum PathFailure {
	/// We failed to initially send the payment and no HTLC was committed to. Contains the relevant
	/// error.
	InitialSend {
		/// The error surfaced from initial send.
		err: APIError,
	},
	/// A hop on the path failed to forward our payment.
	OnPath {
		/// If present, this [`NetworkUpdate`] should be applied to the [`NetworkGraph`] so that routing
		/// decisions can take into account the update.
		///
		/// [`NetworkUpdate`]: crate::routing::gossip::NetworkUpdate
		/// [`NetworkGraph`]: crate::routing::gossip::NetworkGraph
		network_update: Option<NetworkUpdate>,
	},
}

impl_writeable_tlv_based_enum_upgradable!(PathFailure,
	(0, OnPath) => {
		(0, network_update, upgradable_option),
	},
	(2, InitialSend) => {
		(0, err, upgradable_required),
	},
);

#[derive(Clone, Debug, PartialEq, Eq)]
/// The reason the channel was closed. See individual variants for more details.
pub enum ClosureReason {
	/// Closure generated from receiving a peer error message.
	///
	/// Our counterparty may have broadcasted their latest commitment state, and we have
	/// as well.
	CounterpartyForceClosed {
		/// The error which the peer sent us.
		///
		/// Be careful about printing the peer_msg, a well-crafted message could exploit
		/// a security vulnerability in the terminal emulator or the logging subsystem.
		/// To be safe, use `Display` on `UntrustedString`
		///
		/// [`UntrustedString`]: crate::types::string::UntrustedString
		peer_msg: UntrustedString,
	},
	/// Closure generated from [`ChannelManager::force_close_broadcasting_latest_txn`] or
	/// [`ChannelManager::force_close_all_channels_broadcasting_latest_txn`], called by the user.
	///
	/// [`ChannelManager::force_close_broadcasting_latest_txn`]: crate::ln::channelmanager::ChannelManager::force_close_broadcasting_latest_txn
	/// [`ChannelManager::force_close_all_channels_broadcasting_latest_txn`]: crate::ln::channelmanager::ChannelManager::force_close_all_channels_broadcasting_latest_txn
	HolderForceClosed {
		/// Whether or not the latest transaction was broadcasted when the channel was force
		/// closed.
		///
		/// This will be set to `Some(true)` for any channels closed after their funding
		/// transaction was (or might have been) broadcasted, and `Some(false)` for any channels
		/// closed prior to their funding transaction being broadcasted.
		///
		/// This will be `None` for objects generated or written by LDK 0.0.123 and
		/// earlier.
		broadcasted_latest_txn: Option<bool>,
		/// The error message provided to [`ChannelManager::force_close_broadcasting_latest_txn`] or
		/// [`ChannelManager::force_close_all_channels_broadcasting_latest_txn`].
		///
		/// This will be the empty string for objects generated or written by LDK 0.1 and earlier.
		///
		/// [`ChannelManager::force_close_broadcasting_latest_txn`]: crate::ln::channelmanager::ChannelManager::force_close_broadcasting_latest_txn
		/// [`ChannelManager::force_close_all_channels_broadcasting_latest_txn`]: crate::ln::channelmanager::ChannelManager::force_close_all_channels_broadcasting_latest_txn
		message: String,
	},
	/// The channel was closed after negotiating a cooperative close and we've now broadcasted
	/// the cooperative close transaction. Note the shutdown may have been initiated by us.
	///
	/// This was only set in versions of LDK prior to 0.0.122.
	// Can be removed once we disallow downgrading to 0.0.121
	LegacyCooperativeClosure,
	/// The channel was closed after negotiating a cooperative close and we've now broadcasted
	/// the cooperative close transaction. This indicates that the shutdown was initiated by our
	/// counterparty.
	///
	/// In rare cases where we initiated closure immediately prior to shutting down without
	/// persisting, this value may be provided for channels we initiated closure for.
	CounterpartyInitiatedCooperativeClosure,
	/// The channel was closed after negotiating a cooperative close and we've now broadcasted
	/// the cooperative close transaction. This indicates that the shutdown was initiated by us.
	LocallyInitiatedCooperativeClosure,
	/// A commitment transaction was confirmed on chain, closing the channel. Most likely this
	/// commitment transaction came from our counterparty, but it may also have come from
	/// a copy of our own `ChannelMonitor`.
	CommitmentTxConfirmed,
	/// The funding transaction failed to confirm in a timely manner on an inbound channel or the
	/// counterparty failed to fund the channel in a timely manner.
	FundingTimedOut,
	/// Closure generated from processing an event, likely a HTLC forward/relay/reception.
	ProcessingError {
		/// A developer-readable error message which we generated.
		err: String,
	},
	/// The peer disconnected prior to funding completing. In this case the spec mandates that we
	/// forget the channel entirely - we can attempt again if the peer reconnects.
	///
	/// This includes cases where we restarted prior to funding completion, including prior to the
	/// initial [`ChannelMonitor`] persistence completing.
	///
	/// In LDK versions prior to 0.0.107 this could also occur if we were unable to connect to the
	/// peer because of mutual incompatibility between us and our channel counterparty.
	///
	/// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
	DisconnectedPeer,
	/// Closure generated from `ChannelManager::read` if the [`ChannelMonitor`] is newer than
	/// the [`ChannelManager`] deserialized.
	///
	/// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor
	/// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
	OutdatedChannelManager,
	/// The counterparty requested a cooperative close of a channel that had not been funded yet.
	/// The channel has been immediately closed.
	CounterpartyCoopClosedUnfundedChannel,
	/// We requested a cooperative close of a channel that had not been funded yet.
	/// The channel has been immediately closed.
	///
	/// Note that events containing this variant will be lost on downgrade to a version of LDK
	/// prior to 0.2.
	LocallyCoopClosedUnfundedChannel,
	/// Another channel in the same funding batch closed before the funding transaction
	/// was ready to be broadcast.
	FundingBatchClosure,
	/// One of our HTLCs timed out in a channel, causing us to force close the channel.
	HTLCsTimedOut,
	/// Our peer provided a feerate which violated our required minimum (fetched from our
	/// [`FeeEstimator`] either as [`ConfirmationTarget::MinAllowedAnchorChannelRemoteFee`] or
	/// [`ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee`]).
	///
	/// [`FeeEstimator`]: crate::chain::chaininterface::FeeEstimator
	/// [`ConfirmationTarget::MinAllowedAnchorChannelRemoteFee`]: crate::chain::chaininterface::ConfirmationTarget::MinAllowedAnchorChannelRemoteFee
	/// [`ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee`]: crate::chain::chaininterface::ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee
	PeerFeerateTooLow {
		/// The feerate on our channel set by our peer.
		peer_feerate_sat_per_kw: u32,
		/// The required feerate we enforce, from our [`FeeEstimator`].
		///
		/// [`FeeEstimator`]: crate::chain::chaininterface::FeeEstimator
		required_feerate_sat_per_kw: u32,
	},
}

impl core::fmt::Display for ClosureReason {
	fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
		f.write_str("Channel closed because ")?;
		match self {
			ClosureReason::CounterpartyForceClosed { peer_msg } => {
				f.write_fmt(format_args!("counterparty force-closed with message: {}", peer_msg))
			},
			ClosureReason::HolderForceClosed { broadcasted_latest_txn, message } => {
				f.write_str("user force-closed the channel with the message \"")?;
				f.write_str(message)?;
				if let Some(brodcasted) = broadcasted_latest_txn {
					write!(
						f,
						"\" and {} the latest transaction",
						if *brodcasted { "broadcasted" } else { "elected not to broadcast" }
					)
				} else {
					Ok(())
				}
			},
			ClosureReason::LegacyCooperativeClosure => {
				f.write_str("the channel was cooperatively closed")
			},
			ClosureReason::CounterpartyInitiatedCooperativeClosure => {
				f.write_str("the channel was cooperatively closed by our peer")
			},
			ClosureReason::LocallyInitiatedCooperativeClosure => {
				f.write_str("the channel was cooperatively closed by us")
			},
			ClosureReason::CommitmentTxConfirmed => {
				f.write_str("commitment or closing transaction was confirmed on chain.")
			},
			ClosureReason::FundingTimedOut => write!(
				f,
				"funding transaction failed to confirm within {} blocks",
				FUNDING_CONF_DEADLINE_BLOCKS
			),
			ClosureReason::ProcessingError { err } => {
				f.write_str("of an exception: ")?;
				f.write_str(&err)
			},
			ClosureReason::DisconnectedPeer => {
				f.write_str("the peer disconnected prior to the channel being funded")
			},
			ClosureReason::OutdatedChannelManager => f.write_str(
				"the ChannelManager read from disk was stale compared to ChannelMonitor(s)",
			),
			ClosureReason::CounterpartyCoopClosedUnfundedChannel => {
				f.write_str("the peer requested the unfunded channel be closed")
			},
			ClosureReason::LocallyCoopClosedUnfundedChannel => {
				f.write_str("we requested the unfunded channel be closed")
			},
			ClosureReason::FundingBatchClosure => {
				f.write_str("another channel in the same funding batch closed")
			},
			ClosureReason::HTLCsTimedOut => f.write_str("htlcs on the channel timed out"),
			ClosureReason::PeerFeerateTooLow {
				peer_feerate_sat_per_kw,
				required_feerate_sat_per_kw,
			} => f.write_fmt(format_args!(
				"peer provided a feerate ({} sat/kw) which was below our lower bound ({} sat/kw)",
				peer_feerate_sat_per_kw, required_feerate_sat_per_kw,
			)),
		}
	}
}

impl_writeable_tlv_based_enum_upgradable!(ClosureReason,
	(0, CounterpartyForceClosed) => { (1, peer_msg, required) },
	(1, FundingTimedOut) => {},
	(2, HolderForceClosed) => {
		(1, broadcasted_latest_txn, option),
		(3, message, (default_value, String::new())),
	},
	(6, CommitmentTxConfirmed) => {},
	(4, LegacyCooperativeClosure) => {},
	(8, ProcessingError) => { (1, err, required) },
	(10, DisconnectedPeer) => {},
	(12, OutdatedChannelManager) => {},
	(13, CounterpartyCoopClosedUnfundedChannel) => {},
	(15, FundingBatchClosure) => {},
	(17, CounterpartyInitiatedCooperativeClosure) => {},
	(19, LocallyInitiatedCooperativeClosure) => {},
	(21, HTLCsTimedOut) => {},
	(23, PeerFeerateTooLow) => {
		(0, peer_feerate_sat_per_kw, required),
		(2, required_feerate_sat_per_kw, required),
	},
	(25, LocallyCoopClosedUnfundedChannel) => {},
);

/// The type of HTLC handling performed in [`Event::HTLCHandlingFailed`].
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum HTLCHandlingFailureType {
	/// We tried forwarding to a channel but failed to do so. An example of such an instance is when
	/// there is insufficient capacity in our outbound channel.
	Forward {
		/// The `node_id` of the next node. For backwards compatibility, this field is
		/// marked as optional, versions prior to 0.0.110 may not always be able to provide
		/// counterparty node information.
		node_id: Option<PublicKey>,
		/// The outgoing `channel_id` between us and the next node.
		channel_id: ChannelId,
	},
	/// Scenario where we are unsure of the next node to forward the HTLC to.
	///
	/// Deprecated: will only be used in versions before LDK v0.2.0. Downgrades will result in
	/// this type being represented as [`Self::InvalidForward`].
	UnknownNextHop {
		/// Short channel id we are requesting to forward an HTLC to.
		requested_forward_scid: u64,
	},
	/// We couldn't forward to the outgoing scid. An example would be attempting to send a duplicate
	/// intercept HTLC.
	///
	/// In LDK v0.2.0 and greater, this variant replaces [`Self::UnknownNextHop`].
	InvalidForward {
		/// Short channel id we are requesting to forward an HTLC to.
		requested_forward_scid: u64,
	},
	/// We couldn't decode the incoming onion to obtain the forwarding details.
	InvalidOnion,
	/// Failure scenario where an HTLC may have been forwarded to be intended for us,
	/// but is invalid for some reason, so we reject it.
	///
	/// Some of the reasons may include:
	/// * HTLC Timeouts
	/// * Excess HTLCs for a payment that we have already fully received, over-paying for the
	///   payment,
	/// * The counterparty node modified the HTLC in transit,
	/// * A probing attack where an intermediary node is trying to detect if we are the ultimate
	///   recipient for a payment.
	Receive {
		/// The payment hash of the payment we attempted to process.
		payment_hash: PaymentHash,
	},
}

impl_writeable_tlv_based_enum_upgradable!(HTLCHandlingFailureType,
	(0, Forward) => {
		(0, node_id, required),
		(2, channel_id, required),
	},
	(1, InvalidForward) => {
		(0, requested_forward_scid, required),
	},
	(2, UnknownNextHop) => {
		(0, requested_forward_scid, required),
	},
	(3, InvalidOnion) => {},
	(4, Receive) => {
		(0, payment_hash, required),
	},
);

/// The reason for HTLC failures in [`Event::HTLCHandlingFailed`].
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum HTLCHandlingFailureReason {
	/// The forwarded HTLC was failed back by the downstream node with an encrypted error reason.
	Downstream,
	/// The HTLC was failed locally by our node.
	Local {
		/// The reason that our node chose to fail the HTLC.
		reason: LocalHTLCFailureReason,
	},
}

impl_writeable_tlv_based_enum!(HTLCHandlingFailureReason,
	(1, Downstream) => {},
	(3, Local) => {
		(0, reason, required),
	},
);

impl From<LocalHTLCFailureReason> for HTLCHandlingFailureReason {
	fn from(value: LocalHTLCFailureReason) -> Self {
		HTLCHandlingFailureReason::Local { reason: value }
	}
}

/// Will be used in [`Event::HTLCIntercepted`] to identify the next hop in the HTLC's path.
/// Currently only used in serialization for the sake of maintaining compatibility. More variants
/// will be added for general-purpose HTLC forward intercepts as well as trampoline forward
/// intercepts in upcoming work.
enum InterceptNextHop {
	FakeScid { requested_next_hop_scid: u64 },
}

impl_writeable_tlv_based_enum!(InterceptNextHop,
	(0, FakeScid) => {
		(0, requested_next_hop_scid, required),
	},
);

/// The reason the payment failed. Used in [`Event::PaymentFailed`].
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum PaymentFailureReason {
	/// The intended recipient rejected our payment.
	///
	/// Also used for [`UnknownRequiredFeatures`] and [`InvoiceRequestRejected`] when downgrading to
	/// version prior to 0.0.124.
	///
	/// [`UnknownRequiredFeatures`]: Self::UnknownRequiredFeatures
	/// [`InvoiceRequestRejected`]: Self::InvoiceRequestRejected
	RecipientRejected,
	/// The user chose to abandon this payment by calling [`ChannelManager::abandon_payment`].
	///
	/// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
	UserAbandoned,
	#[cfg_attr(
		feature = "std",
		doc = "We exhausted all of our retry attempts while trying to send the payment, or we"
	)]
	#[cfg_attr(feature = "std", doc = "exhausted the [`Retry::Timeout`] if the user set one.")]
	#[cfg_attr(
		not(feature = "std"),
		doc = "We exhausted all of our retry attempts while trying to send the payment."
	)]
	/// If at any point a retry attempt failed while being forwarded along the path, an [`Event::PaymentPathFailed`] will
	/// have come before this.
	#[cfg_attr(feature = "std", doc = "")]
	#[cfg_attr(
		feature = "std",
		doc = "[`Retry::Timeout`]: crate::ln::channelmanager::Retry::Timeout"
	)]
	RetriesExhausted,
	/// Either the BOLT 12 invoice was expired by the time we received it or the payment expired while
	/// retrying based on the provided [`PaymentParameters::expiry_time`].
	///
	/// Also used for [`InvoiceRequestExpired`] when downgrading to version prior to 0.0.124.
	///
	/// [`PaymentParameters::expiry_time`]: crate::routing::router::PaymentParameters::expiry_time
	/// [`InvoiceRequestExpired`]: Self::InvoiceRequestExpired
	PaymentExpired,
	/// We failed to find a route while sending or retrying the payment.
	///
	/// Note that this generally indicates that we've exhausted the available set of possible
	/// routes - we tried the payment over a few routes but were not able to find any further
	/// candidate routes beyond those.
	///
	/// Also used for [`BlindedPathCreationFailed`] when downgrading to versions prior to 0.0.124.
	///
	/// [`BlindedPathCreationFailed`]: Self::BlindedPathCreationFailed
	RouteNotFound,
	/// This error should generally never happen. This likely means that there is a problem with
	/// your router.
	UnexpectedError,
	/// An invoice was received that required unknown features.
	UnknownRequiredFeatures,
	/// A [`Bolt12Invoice`] was not received in a reasonable amount of time.
	InvoiceRequestExpired,
	/// An [`InvoiceRequest`] for the payment was rejected by the recipient.
	///
	/// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
	InvoiceRequestRejected,
	/// Failed to create a blinded path back to ourselves.
	/// We attempted to initiate payment to a static invoice but failed to create a reply path for our
	/// [`HeldHtlcAvailable`] message.
	///
	/// [`HeldHtlcAvailable`]: crate::onion_message::async_payments::HeldHtlcAvailable
	BlindedPathCreationFailed,
}

impl_writeable_tlv_based_enum_upgradable!(PaymentFailureReason,
	(0, RecipientRejected) => {},
	(1, UnknownRequiredFeatures) => {},
	(2, UserAbandoned) => {},
	(3, InvoiceRequestExpired) => {},
	(4, RetriesExhausted) => {},
	(5, InvoiceRequestRejected) => {},
	(6, PaymentExpired) => {},
	(7, BlindedPathCreationFailed) => {},
	(8, RouteNotFound) => {},
	(10, UnexpectedError) => {},
);

/// Used to indicate the kind of funding for this channel by the channel acceptor (us).
///
/// Allows the differentiation between a request for a dual-funded and non-dual-funded channel.
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum InboundChannelFunds {
	/// For a non-dual-funded channel, the `push_msat` value from the channel initiator to us.
	PushMsat(u64),
	/// Indicates the open request is for a dual funded channel.
	///
	/// Note that these channels do not support starting with initial funds pushed from the counterparty,
	/// who is the channel opener in this case.
	DualFunded,
}

/// An Event which you should probably take some action in response to.
///
/// Note that while Writeable and Readable are implemented for Event, you probably shouldn't use
/// them directly as they don't round-trip exactly (for example FundingGenerationReady is never
/// written as it makes no sense to respond to it after reconnecting to peers).
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum Event {
	/// Used to indicate that the client should generate a funding transaction with the given
	/// parameters and then call [`ChannelManager::funding_transaction_generated`].
	/// Generated in [`ChannelManager`] message handling.
	/// Note that *all inputs* in the funding transaction must spend SegWit outputs or your
	/// counterparty can steal your funds!
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`), but won't be persisted across restarts.
	///
	/// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
	/// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
	FundingGenerationReady {
		/// The random channel_id we picked which you'll need to pass into
		/// [`ChannelManager::funding_transaction_generated`].
		///
		/// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
		temporary_channel_id: ChannelId,
		/// The counterparty's node_id, which you'll need to pass back into
		/// [`ChannelManager::funding_transaction_generated`].
		///
		/// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
		counterparty_node_id: PublicKey,
		/// The value, in satoshis, that the output should have.
		channel_value_satoshis: u64,
		/// The script which should be used in the transaction output.
		output_script: ScriptBuf,
		/// The `user_channel_id` value passed in to [`ChannelManager::create_channel`] for outbound
		/// channels, or to [`ChannelManager::accept_inbound_channel`] for inbound channels if
		/// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true. Otherwise
		/// `user_channel_id` will be randomized for an inbound channel.  This may be zero for objects
		/// serialized with LDK versions prior to 0.0.113.
		///
		/// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
		/// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
		/// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
		user_channel_id: u128,
	},
	/// Used to indicate that the counterparty node has provided the signature(s) required to
	/// recover our funds in case they go offline.
	///
	/// It is safe (and your responsibility) to broadcast the funding transaction upon receiving this
	/// event.
	///
	/// This event is only emitted if you called
	/// [`ChannelManager::unsafe_manual_funding_transaction_generated`] instead of
	/// [`ChannelManager::funding_transaction_generated`].
	///
	/// [`ChannelManager::unsafe_manual_funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::unsafe_manual_funding_transaction_generated
	/// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
	FundingTxBroadcastSafe {
		/// The `channel_id` indicating which channel has reached this stage.
		channel_id: ChannelId,
		/// The `user_channel_id` value passed in to [`ChannelManager::create_channel`].
		///
		/// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
		user_channel_id: u128,
		/// The outpoint of the channel's funding transaction.
		funding_txo: OutPoint,
		/// The `node_id` of the channel counterparty.
		counterparty_node_id: PublicKey,
		/// The `temporary_channel_id` this channel used to be known by during channel establishment.
		former_temporary_channel_id: ChannelId,
	},
	/// Indicates that we've been offered a payment and it needs to be claimed via calling
	/// [`ChannelManager::claim_funds`] with the preimage given in [`PaymentPurpose`].
	///
	/// Note that if the preimage is not known, you should call
	/// [`ChannelManager::fail_htlc_backwards`] or [`ChannelManager::fail_htlc_backwards_with_reason`]
	/// to free up resources for this HTLC and avoid network congestion.
	///
	/// If [`Event::PaymentClaimable::onion_fields`] is `Some`, and includes custom TLVs with even type
	/// numbers, you should use [`ChannelManager::fail_htlc_backwards_with_reason`] with
	/// [`FailureCode::InvalidOnionPayload`] if you fail to understand and handle the contents, or
	/// [`ChannelManager::claim_funds_with_known_custom_tlvs`] upon successful handling.
	/// If you don't intend to check for custom TLVs, you can simply use
	/// [`ChannelManager::claim_funds`], which will automatically fail back even custom TLVs.
	///
	/// If you fail to call [`ChannelManager::claim_funds`],
	/// [`ChannelManager::claim_funds_with_known_custom_tlvs`],
	/// [`ChannelManager::fail_htlc_backwards`], or
	/// [`ChannelManager::fail_htlc_backwards_with_reason`] within the HTLC's timeout, the HTLC will
	/// be automatically failed.
	///
	/// # Note
	/// LDK will not stop an inbound payment from being paid multiple times, so multiple
	/// `PaymentClaimable` events may be generated for the same payment. In such a case it is
	/// polite (and required in the lightning specification) to fail the payment the second time
	/// and give the sender their money back rather than accepting double payment.
	///
	/// # Note
	/// This event used to be called `PaymentReceived` in LDK versions 0.0.112 and earlier.
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`) and will be persisted across restarts.
	///
	/// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
	/// [`ChannelManager::claim_funds_with_known_custom_tlvs`]: crate::ln::channelmanager::ChannelManager::claim_funds_with_known_custom_tlvs
	/// [`FailureCode::InvalidOnionPayload`]: crate::ln::channelmanager::FailureCode::InvalidOnionPayload
	/// [`ChannelManager::fail_htlc_backwards`]: crate::ln::channelmanager::ChannelManager::fail_htlc_backwards
	/// [`ChannelManager::fail_htlc_backwards_with_reason`]: crate::ln::channelmanager::ChannelManager::fail_htlc_backwards_with_reason
	PaymentClaimable {
		/// The node that will receive the payment after it has been claimed.
		/// This is useful to identify payments received via [phantom nodes].
		/// This field will always be filled in when the event was generated by LDK versions
		/// 0.0.113 and above.
		///
		/// [phantom nodes]: crate::sign::PhantomKeysManager
		receiver_node_id: Option<PublicKey>,
		/// The hash for which the preimage should be handed to the ChannelManager. Note that LDK will
		/// not stop you from registering duplicate payment hashes for inbound payments.
		payment_hash: PaymentHash,
		/// The fields in the onion which were received with each HTLC. Only fields which were
		/// identical in each HTLC involved in the payment will be included here.
		///
		/// Payments received on LDK versions prior to 0.0.115 will have this field unset.
		onion_fields: Option<RecipientOnionFields>,
		/// The value, in thousandths of a satoshi, that this payment is claimable for. May be greater
		/// than the invoice amount.
		///
		/// May be less than the invoice amount if [`ChannelConfig::accept_underpaying_htlcs`] is set
		/// and the previous hop took an extra fee.
		///
		/// # Note
		/// If [`ChannelConfig::accept_underpaying_htlcs`] is set and you claim without verifying this
		/// field, you may lose money!
		///
		/// [`ChannelConfig::accept_underpaying_htlcs`]: crate::util::config::ChannelConfig::accept_underpaying_htlcs
		amount_msat: u64,
		/// The value, in thousands of a satoshi, that was skimmed off of this payment as an extra fee
		/// taken by our channel counterparty.
		///
		/// Will always be 0 unless [`ChannelConfig::accept_underpaying_htlcs`] is set.
		///
		/// [`ChannelConfig::accept_underpaying_htlcs`]: crate::util::config::ChannelConfig::accept_underpaying_htlcs
		counterparty_skimmed_fee_msat: u64,
		/// Information for claiming this received payment, based on whether the purpose of the
		/// payment is to pay an invoice or to send a spontaneous payment.
		purpose: PaymentPurpose,
		/// The `(channel_id, user_channel_id)` pairs over which the payment was received.
		///
		/// This will be an incomplete vector for MPP payment events created/serialized using LDK version 0.1.0 and prior.
		receiving_channel_ids: Vec<(ChannelId, Option<u128>)>,
		/// The block height at which this payment will be failed back and will no longer be
		/// eligible for claiming.
		///
		/// Prior to this height, a call to [`ChannelManager::claim_funds`] is guaranteed to
		/// succeed, however you should wait for [`Event::PaymentClaimed`] to be sure.
		///
		/// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
		claim_deadline: Option<u32>,
		/// A unique ID describing this payment (derived from the list of HTLCs in the payment).
		///
		/// Payers may pay for the same [`PaymentHash`] multiple times (though this is unsafe and
		/// an intermediary node may steal the funds). Thus, in order to accurately track when
		/// payments are received and claimed, you should use this identifier.
		///
		/// Only filled in for payments received on LDK versions 0.1 and higher.
		payment_id: Option<PaymentId>,
	},
	/// Indicates a payment has been claimed and we've received money!
	///
	/// This most likely occurs when [`ChannelManager::claim_funds`] has been called in response
	/// to an [`Event::PaymentClaimable`]. However, if we previously crashed during a
	/// [`ChannelManager::claim_funds`] call you may see this event without a corresponding
	/// [`Event::PaymentClaimable`] event.
	///
	/// # Note
	/// LDK will not stop an inbound payment from being paid multiple times, so multiple
	/// `PaymentClaimable` events may be generated for the same payment. If you then call
	/// [`ChannelManager::claim_funds`] twice for the same [`Event::PaymentClaimable`] you may get
	/// multiple `PaymentClaimed` events.
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`) and will be persisted across restarts.
	///
	/// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
	PaymentClaimed {
		/// The node that received the payment.
		/// This is useful to identify payments which were received via [phantom nodes].
		/// This field will always be filled in when the event was generated by LDK versions
		/// 0.0.113 and above.
		///
		/// [phantom nodes]: crate::sign::PhantomKeysManager
		receiver_node_id: Option<PublicKey>,
		/// The payment hash of the claimed payment. Note that LDK will not stop you from
		/// registering duplicate payment hashes for inbound payments.
		payment_hash: PaymentHash,
		/// The value, in thousandths of a satoshi, that this payment is for. May be greater than the
		/// invoice amount.
		amount_msat: u64,
		/// The purpose of the claimed payment, i.e. whether the payment was for an invoice or a
		/// spontaneous payment.
		purpose: PaymentPurpose,
		/// The HTLCs that comprise the claimed payment. This will be empty for events serialized prior
		/// to LDK version 0.0.117.
		htlcs: Vec<ClaimedHTLC>,
		/// The sender-intended sum total of all the MPP parts. This will be `None` for events
		/// serialized prior to LDK version 0.0.117.
		sender_intended_total_msat: Option<u64>,
		/// The fields in the onion which were received with each HTLC. Only fields which were
		/// identical in each HTLC involved in the payment will be included here.
		///
		/// Payments received on LDK versions prior to 0.0.124 will have this field unset.
		onion_fields: Option<RecipientOnionFields>,
		/// A unique ID describing this payment (derived from the list of HTLCs in the payment).
		///
		/// Payers may pay for the same [`PaymentHash`] multiple times (though this is unsafe and
		/// an intermediary node may steal the funds). Thus, in order to accurately track when
		/// payments are received and claimed, you should use this identifier.
		///
		/// Only filled in for payments received on LDK versions 0.1 and higher.
		payment_id: Option<PaymentId>,
	},
	/// Indicates that a peer connection with a node is needed in order to send an [`OnionMessage`].
	///
	/// Typically, this happens when a [`MessageRouter`] is unable to find a complete path to a
	/// [`Destination`]. Once a connection is established, any messages buffered by an
	/// [`OnionMessageHandler`] may be sent.
	///
	/// This event will not be generated for onion message forwards; only for sends including
	/// replies. Handlers should connect to the node otherwise any buffered messages may be lost.
	///
	/// # Failure Behavior and Persistence
	/// This event won't be replayed after failures-to-handle
	/// (i.e., the event handler returning `Err(ReplayEvent ())`), and also won't be persisted
	/// across restarts.
	///
	/// [`OnionMessage`]: msgs::OnionMessage
	/// [`MessageRouter`]: crate::onion_message::messenger::MessageRouter
	/// [`Destination`]: crate::onion_message::messenger::Destination
	/// [`OnionMessageHandler`]: crate::ln::msgs::OnionMessageHandler
	ConnectionNeeded {
		/// The node id for the node needing a connection.
		node_id: PublicKey,
		/// Sockets for connecting to the node.
		addresses: Vec<msgs::SocketAddress>,
	},
	/// Indicates a [`Bolt12Invoice`] in response to an [`InvoiceRequest`] or a [`Refund`] was
	/// received.
	///
	/// This event will only be generated if [`UserConfig::manually_handle_bolt12_invoices`] is set.
	/// Use [`ChannelManager::send_payment_for_bolt12_invoice`] to pay the invoice or
	/// [`ChannelManager::abandon_payment`] to abandon the associated payment. See those docs for
	/// further details.
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`) and will be persisted across restarts.
	///
	/// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
	/// [`Refund`]: crate::offers::refund::Refund
	/// [`UserConfig::manually_handle_bolt12_invoices`]: crate::util::config::UserConfig::manually_handle_bolt12_invoices
	/// [`ChannelManager::send_payment_for_bolt12_invoice`]: crate::ln::channelmanager::ChannelManager::send_payment_for_bolt12_invoice
	/// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
	InvoiceReceived {
		/// The `payment_id` associated with payment for the invoice.
		payment_id: PaymentId,
		/// The invoice to pay.
		invoice: Bolt12Invoice,
		/// The context of the [`BlindedMessagePath`] used to send the invoice.
		///
		/// [`BlindedMessagePath`]: crate::blinded_path::message::BlindedMessagePath
		context: Option<OffersContext>,
		/// A responder for replying with an [`InvoiceError`] if needed.
		///
		/// `None` if the invoice wasn't sent with a reply path.
		///
		/// [`InvoiceError`]: crate::offers::invoice_error::InvoiceError
		responder: Option<Responder>,
	},
	/// Indicates an outbound payment we made succeeded (i.e. it made it all the way to its target
	/// and we got back the payment preimage for it).
	///
	/// Note for MPP payments: in rare cases, this event may be preceded by a `PaymentPathFailed`
	/// event. In this situation, you SHOULD treat this payment as having succeeded.
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`) and will be persisted across restarts.
	PaymentSent {
		/// The `payment_id` passed to [`ChannelManager::send_payment`].
		///
		/// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
		payment_id: Option<PaymentId>,
		/// The preimage to the hash given to ChannelManager::send_payment.
		/// Note that this serves as a payment receipt, if you wish to have such a thing, you must
		/// store it somehow!
		payment_preimage: PaymentPreimage,
		/// The hash that was given to [`ChannelManager::send_payment`].
		///
		/// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
		payment_hash: PaymentHash,
		/// The total amount that was paid, across all paths.
		///
		/// Note that, like [`Route::get_total_amount`], this does *not* include the paid fees.
		///
		/// This is only `None` for payments initiated on LDK versions prior to 0.2.
		///
		/// [`Route::get_total_amount`]: crate::routing::router::Route::get_total_amount
		amount_msat: Option<u64>,
		/// The total fee which was spent at intermediate hops in this payment, across all paths.
		///
		/// Note that, like [`Route::get_total_fees`], this does *not* include any potential
		/// overpayment to the recipient node.
		///
		/// If the recipient or an intermediate node misbehaves and gives us free money, this may
		/// overstate the amount paid, though this is unlikely.
		///
		/// This is only `None` for payments initiated on LDK versions prior to 0.0.103.
		///
		/// [`Route::get_total_fees`]: crate::routing::router::Route::get_total_fees
		fee_paid_msat: Option<u64>,
		/// The BOLT 12 invoice that was paid. `None` if the payment was a non BOLT 12 payment.
		///
		/// The BOLT 12 invoice is useful for proof of payment because it contains the
		/// payment hash. A third party can verify that the payment was made by
		/// showing the invoice and confirming that the payment hash matches
		/// the hash of the payment preimage.
		///
		/// However, the [`PaidBolt12Invoice`] can also be of type [`StaticInvoice`], which
		/// is a special [`Bolt12Invoice`] where proof of payment is not possible.
		///
		/// [`StaticInvoice`]: crate::offers::static_invoice::StaticInvoice
		bolt12_invoice: Option<PaidBolt12Invoice>,
	},
	/// Indicates an outbound payment failed. Individual [`Event::PaymentPathFailed`] events
	/// provide failure information for each path attempt in the payment, including retries.
	///
	/// This event is provided once there are no further pending HTLCs for the payment and the
	/// payment is no longer retryable, due either to the [`Retry`] provided or
	/// [`ChannelManager::abandon_payment`] having been called for the corresponding payment.
	///
	/// In exceedingly rare cases, it is possible that an [`Event::PaymentFailed`] is generated for
	/// a payment after an [`Event::PaymentSent`] event for this same payment has already been
	/// received and processed. In this case, the [`Event::PaymentFailed`] event MUST be ignored,
	/// and the payment MUST be treated as having succeeded.
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`) and will be persisted across restarts.
	///
	/// [`Retry`]: crate::ln::channelmanager::Retry
	/// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
	PaymentFailed {
		/// The `payment_id` passed to [`ChannelManager::send_payment`].
		///
		/// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
		payment_id: PaymentId,
		/// The hash that was given to [`ChannelManager::send_payment`]. `None` if the payment failed
		/// before receiving an invoice when paying a BOLT12 [`Offer`].
		///
		/// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
		/// [`Offer`]: crate::offers::offer::Offer
		payment_hash: Option<PaymentHash>,
		/// The reason the payment failed. This is only `None` for events generated or serialized
		/// by versions prior to 0.0.115, or when downgrading to a version with a reason that was
		/// added after.
		reason: Option<PaymentFailureReason>,
	},
	/// Indicates that a path for an outbound payment was successful.
	///
	/// Always generated after [`Event::PaymentSent`] and thus useful for scoring channels. See
	/// [`Event::PaymentSent`] for obtaining the payment preimage.
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`) and will be persisted across restarts.
	PaymentPathSuccessful {
		/// The `payment_id` passed to [`ChannelManager::send_payment`].
		///
		/// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
		payment_id: PaymentId,
		/// The hash that was given to [`ChannelManager::send_payment`].
		///
		/// This will be `Some` for all payments which completed on LDK 0.0.104 or later.
		///
		/// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
		payment_hash: Option<PaymentHash>,
		/// The payment path that was successful.
		///
		/// May contain a closed channel if the HTLC sent along the path was fulfilled on chain.
		path: Path,
		/// The time that each hop indicated it held the HTLC.
		///
		/// The unit in which the hold times are expressed are 100's of milliseconds. So a hop
		/// reporting 2 is a hold time that corresponds to between 200 and 299 milliseconds.
		///
		/// We expect that at each hop the actual hold time will be strictly greater than the hold
		/// time of the following hops, as a node along the path shouldn't have completed the HTLC
		/// until the next node has completed it. Note that because hold times are in 100's of ms,
		/// hold times as reported are likely to often be equal across hops.
		///
		/// If our peer didn't provide attribution data or the HTLC resolved on chain, the list
		/// will be empty.
		///
		/// Each entry will correspond with one entry in [`Path::hops`], or, thereafter, the
		/// [`BlindedTail::trampoline_hops`] in [`Path::blinded_tail`]. Because not all nodes
		/// support hold times, the list may be shorter than the number of hops in the path.
		hold_times: Vec<u32>,
	},
	/// Indicates an outbound HTLC we sent failed, likely due to an intermediary node being unable to
	/// handle the HTLC.
	///
	/// Note that this does *not* indicate that all paths for an MPP payment have failed, see
	/// [`Event::PaymentFailed`].
	///
	/// See [`ChannelManager::abandon_payment`] for giving up on this payment before its retries have
	/// been exhausted.
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`) and will be persisted across restarts.
	///
	/// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
	PaymentPathFailed {
		/// The `payment_id` passed to [`ChannelManager::send_payment`].
		///
		/// This will be `Some` for all payment paths which failed on LDK 0.0.103 or later.
		///
		/// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
		/// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
		payment_id: Option<PaymentId>,
		/// The hash that was given to [`ChannelManager::send_payment`].
		///
		/// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
		payment_hash: PaymentHash,
		/// Indicates the payment was rejected for some reason by the recipient. This implies that
		/// the payment has failed, not just the route in question. If this is not set, the payment may
		/// be retried via a different route.
		payment_failed_permanently: bool,
		/// Extra error details based on the failure type. May contain an update that needs to be
		/// applied to the [`NetworkGraph`].
		///
		/// [`NetworkGraph`]: crate::routing::gossip::NetworkGraph
		failure: PathFailure,
		/// The payment path that failed.
		path: Path,
		/// The channel responsible for the failed payment path.
		///
		/// Note that for route hints or for the first hop in a path this may be an SCID alias and
		/// may not refer to a channel in the public network graph. These aliases may also collide
		/// with channels in the public network graph.
		///
		/// If this is `Some`, then the corresponding channel should be avoided when the payment is
		/// retried. May be `None` for older [`Event`] serializations.
		short_channel_id: Option<u64>,
		#[cfg(any(test, feature = "_test_utils"))]
		error_code: Option<u16>,
		#[cfg(any(test, feature = "_test_utils"))]
		error_data: Option<Vec<u8>>,
		/// The time that each hop indicated it held the HTLC.
		///
		/// The unit in which the hold times are expressed are 100's of milliseconds. So a hop
		/// reporting 2 is a hold time that corresponds to between 200 and 299 milliseconds.
		///
		/// We expect that at each hop the actual hold time will be strictly greater than the hold
		/// time of the following hops, as a node along the path shouldn't have completed the HTLC
		/// until the next node has completed it. Note that because hold times are in 100's of ms,
		/// hold times as reported are likely to often be equal across hops.
		///
		/// If our peer didn't provide attribution data or the HTLC resolved on chain, the list
		/// will be empty.
		///
		/// Each entry will correspond with one entry in [`Path::hops`], or, thereafter, the
		/// [`BlindedTail::trampoline_hops`] in [`Path::blinded_tail`]. Because not all nodes
		/// support hold times, the list may be shorter than the number of hops in the path.
		hold_times: Vec<u32>,
	},
	/// Indicates that a probe payment we sent returned successful, i.e., only failed at the destination.
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`) and will be persisted across restarts.
	ProbeSuccessful {
		/// The id returned by [`ChannelManager::send_probe`].
		///
		/// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
		payment_id: PaymentId,
		/// The hash generated by [`ChannelManager::send_probe`].
		///
		/// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
		payment_hash: PaymentHash,
		/// The payment path that was successful.
		path: Path,
	},
	/// Indicates that a probe payment we sent failed at an intermediary node on the path.
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`) and will be persisted across restarts.
	ProbeFailed {
		/// The id returned by [`ChannelManager::send_probe`].
		///
		/// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
		payment_id: PaymentId,
		/// The hash generated by [`ChannelManager::send_probe`].
		///
		/// [`ChannelManager::send_probe`]: crate::ln::channelmanager::ChannelManager::send_probe
		payment_hash: PaymentHash,
		/// The payment path that failed.
		path: Path,
		/// The channel responsible for the failed probe.
		///
		/// Note that for route hints or for the first hop in a path this may be an SCID alias and
		/// may not refer to a channel in the public network graph. These aliases may also collide
		/// with channels in the public network graph.
		short_channel_id: Option<u64>,
	},
	/// Used to indicate that we've intercepted an HTLC forward. This event will only be generated if
	/// you've encoded an intercept scid in the receiver's invoice route hints using
	/// [`ChannelManager::get_intercept_scid`] and have set [`UserConfig::accept_intercept_htlcs`].
	///
	/// [`ChannelManager::forward_intercepted_htlc`] or
	/// [`ChannelManager::fail_intercepted_htlc`] MUST be called in response to this event. See
	/// their docs for more information.
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`) and will be persisted across restarts.
	///
	/// [`ChannelManager::get_intercept_scid`]: crate::ln::channelmanager::ChannelManager::get_intercept_scid
	/// [`UserConfig::accept_intercept_htlcs`]: crate::util::config::UserConfig::accept_intercept_htlcs
	/// [`ChannelManager::forward_intercepted_htlc`]: crate::ln::channelmanager::ChannelManager::forward_intercepted_htlc
	/// [`ChannelManager::fail_intercepted_htlc`]: crate::ln::channelmanager::ChannelManager::fail_intercepted_htlc
	HTLCIntercepted {
		/// An id to help LDK identify which HTLC is being forwarded or failed.
		intercept_id: InterceptId,
		/// The fake scid that was programmed as the next hop's scid, generated using
		/// [`ChannelManager::get_intercept_scid`].
		///
		/// [`ChannelManager::get_intercept_scid`]: crate::ln::channelmanager::ChannelManager::get_intercept_scid
		requested_next_hop_scid: u64,
		/// The payment hash used for this HTLC.
		payment_hash: PaymentHash,
		/// How many msats were received on the inbound edge of this HTLC.
		inbound_amount_msat: u64,
		/// How many msats the payer intended to route to the next node. Depending on the reason you are
		/// intercepting this payment, you might take a fee by forwarding less than this amount.
		/// Forwarding less than this amount may break compatibility with LDK versions prior to 0.0.116.
		///
		/// Note that LDK will NOT check that expected fees were factored into this value. You MUST
		/// check that whatever fee you want has been included here or subtract it as required. Further,
		/// LDK will not stop you from forwarding more than you received.
		expected_outbound_amount_msat: u64,
	},
	/// Used to indicate that an output which you should know how to spend was confirmed on chain
	/// and is now spendable.
	///
	/// Such an output will *never* be spent directly by LDK, and are not at risk of your
	/// counterparty spending them due to some kind of timeout. Thus, you need to store them
	/// somewhere and spend them when you create on-chain transactions.
	///
	/// You may hand them to the [`OutputSweeper`] utility which will store and (re-)generate spending
	/// transactions for you.
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`) and will be persisted across restarts.
	///
	/// [`OutputSweeper`]: crate::util::sweep::OutputSweeper
	SpendableOutputs {
		/// The outputs which you should store as spendable by you.
		outputs: Vec<SpendableOutputDescriptor>,
		/// The `channel_id` indicating which channel the spendable outputs belong to.
		///
		/// This will always be `Some` for events generated by LDK versions 0.0.117 and above.
		channel_id: Option<ChannelId>,
	},
	/// This event is generated when a payment has been successfully forwarded through us and a
	/// forwarding fee earned.
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`) and will be persisted across restarts.
	PaymentForwarded {
		/// The channel id of the incoming channel between the previous node and us.
		///
		/// This is only `None` for events generated or serialized by versions prior to 0.0.107.
		prev_channel_id: Option<ChannelId>,
		/// The channel id of the outgoing channel between the next node and us.
		///
		/// This is only `None` for events generated or serialized by versions prior to 0.0.107.
		next_channel_id: Option<ChannelId>,
		/// The `user_channel_id` of the incoming channel between the previous node and us.
		///
		/// This is only `None` for events generated or serialized by versions prior to 0.0.122.
		prev_user_channel_id: Option<u128>,
		/// The `user_channel_id` of the outgoing channel between the next node and us.
		///
		/// This will be `None` if the payment was settled via an on-chain transaction. See the
		/// caveat described for the `total_fee_earned_msat` field. Moreover it will be `None` for
		/// events generated or serialized by versions prior to 0.0.122.
		next_user_channel_id: Option<u128>,
		/// The node id of the previous node.
		///
		/// This is only `None` for HTLCs received prior to 0.1 or for events serialized by
		/// versions prior to 0.1
		prev_node_id: Option<PublicKey>,
		/// The node id of the next node.
		///
		/// This is only `None` for HTLCs received prior to 0.1 or for events serialized by
		/// versions prior to 0.1
		next_node_id: Option<PublicKey>,
		/// The total fee, in milli-satoshis, which was earned as a result of the payment.
		///
		/// Note that if we force-closed the channel over which we forwarded an HTLC while the HTLC
		/// was pending, the amount the next hop claimed will have been rounded down to the nearest
		/// whole satoshi. Thus, the fee calculated here may be higher than expected as we still
		/// claimed the full value in millisatoshis from the source. In this case,
		/// `claim_from_onchain_tx` will be set.
		///
		/// If the channel which sent us the payment has been force-closed, we will claim the funds
		/// via an on-chain transaction. In that case we do not yet know the on-chain transaction
		/// fees which we will spend and will instead set this to `None`. It is possible duplicate
		/// `PaymentForwarded` events are generated for the same payment iff `total_fee_earned_msat` is
		/// `None`.
		total_fee_earned_msat: Option<u64>,
		/// The share of the total fee, in milli-satoshis, which was withheld in addition to the
		/// forwarding fee.
		///
		/// This will only be `Some` if we forwarded an intercepted HTLC with less than the
		/// expected amount. This means our counterparty accepted to receive less than the invoice
		/// amount, e.g., by claiming the payment featuring a corresponding
		/// [`PaymentClaimable::counterparty_skimmed_fee_msat`].
		///
		/// Will also always be `None` for events serialized with LDK prior to version 0.0.122.
		///
		/// The caveat described above the `total_fee_earned_msat` field applies here as well.
		///
		/// [`PaymentClaimable::counterparty_skimmed_fee_msat`]: Self::PaymentClaimable::counterparty_skimmed_fee_msat
		skimmed_fee_msat: Option<u64>,
		/// If this is `true`, the forwarded HTLC was claimed by our counterparty via an on-chain
		/// transaction.
		claim_from_onchain_tx: bool,
		/// The final amount forwarded, in milli-satoshis, after the fee is deducted.
		///
		/// The caveat described above the `total_fee_earned_msat` field applies here as well.
		outbound_amount_forwarded_msat: Option<u64>,
	},
	/// Used to indicate that a channel with the given `channel_id` is being opened and pending
	/// confirmation on-chain.
	///
	/// This event is emitted when the funding transaction has been signed and is broadcast to the
	/// network. For 0conf channels it will be immediately followed by the corresponding
	/// [`Event::ChannelReady`] event.
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`) and will be persisted across restarts.
	ChannelPending {
		/// The `channel_id` of the channel that is pending confirmation.
		channel_id: ChannelId,
		/// The `user_channel_id` value passed in to [`ChannelManager::create_channel`] for outbound
		/// channels, or to [`ChannelManager::accept_inbound_channel`] for inbound channels if
		/// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true. Otherwise
		/// `user_channel_id` will be randomized for an inbound channel.
		///
		/// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
		/// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
		/// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
		user_channel_id: u128,
		/// The `temporary_channel_id` this channel used to be known by during channel establishment.
		///
		/// Will be `None` for channels created prior to LDK version 0.0.115.
		former_temporary_channel_id: Option<ChannelId>,
		/// The `node_id` of the channel counterparty.
		counterparty_node_id: PublicKey,
		/// The outpoint of the channel's funding transaction.
		funding_txo: OutPoint,
		/// The features that this channel will operate with.
		///
		/// Will be `None` for channels created prior to LDK version 0.0.122.
		channel_type: Option<ChannelTypeFeatures>,
	},
	/// Used to indicate that a channel with the given `channel_id` is ready to be used. This event
	/// is emitted when
	/// - the initial funding transaction has been confirmed on-chain to an acceptable depth
	///   according to both parties (i.e., `channel_ready` messages were exchanged),
	/// - a splice funding transaction has been confirmed on-chain to an acceptable depth according
	///   to both parties (i.e., `splice_locked` messages were exchanged), or,
	/// - in case of a 0conf channel, when both parties have confirmed the channel establishment.
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`) and will be persisted across restarts.
	ChannelReady {
		/// The `channel_id` of the channel that is ready.
		channel_id: ChannelId,
		/// The `user_channel_id` value passed in to [`ChannelManager::create_channel`] for outbound
		/// channels, or to [`ChannelManager::accept_inbound_channel`] for inbound channels if
		/// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true. Otherwise
		/// `user_channel_id` will be randomized for an inbound channel.
		///
		/// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
		/// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
		/// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
		user_channel_id: u128,
		/// The `node_id` of the channel counterparty.
		counterparty_node_id: PublicKey,
		/// The outpoint of the channel's funding transaction.
		///
		/// Will be `None` if the channel's funding transaction reached an acceptable depth prior to
		/// version 0.2.
		funding_txo: Option<OutPoint>,
		/// The features that this channel will operate with.
		channel_type: ChannelTypeFeatures,
	},
	/// Used to indicate that a channel that got past the initial handshake with the given `channel_id` is in the
	/// process of closure. This includes previously opened channels, and channels that time out from not being funded.
	///
	/// Note that this event is only triggered for accepted channels: if the
	/// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true and the channel is
	/// rejected, no `ChannelClosed` event will be sent.
	///
	/// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
	/// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`) and will be persisted across restarts.
	ChannelClosed {
		/// The `channel_id` of the channel which has been closed. Note that on-chain transactions
		/// resolving the channel are likely still awaiting confirmation.
		channel_id: ChannelId,
		/// The `user_channel_id` value passed in to [`ChannelManager::create_channel`] for outbound
		/// channels, or to [`ChannelManager::accept_inbound_channel`] for inbound channels if
		/// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true. Otherwise
		/// `user_channel_id` will be randomized for inbound channels.
		/// This may be zero for inbound channels serialized prior to 0.0.113 and will always be
		/// zero for objects serialized with LDK versions prior to 0.0.102.
		///
		/// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
		/// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
		/// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
		user_channel_id: u128,
		/// The reason the channel was closed.
		reason: ClosureReason,
		/// Counterparty in the closed channel.
		///
		/// This field will be `None` for objects serialized prior to LDK 0.0.117.
		counterparty_node_id: Option<PublicKey>,
		/// Channel capacity of the closing channel (sats).
		///
		/// This field will be `None` for objects serialized prior to LDK 0.0.117.
		channel_capacity_sats: Option<u64>,

		/// The original channel funding TXO; this helps checking for the existence and confirmation
		/// status of the closing tx.
		/// Note that for instances serialized in v0.0.119 or prior this will be missing (None).
		channel_funding_txo: Option<transaction::OutPoint>,
		/// An upper bound on the our last local balance in msats before the channel was closed.
		///
		/// Will overstate our balance as it ignores pending outbound HTLCs and transaction fees.
		///
		/// For more accurate balances including fee information see
		/// [`ChainMonitor::get_claimable_balances`].
		///
		/// This field will be `None` only for objects serialized prior to LDK 0.1.
		///
		/// [`ChainMonitor::get_claimable_balances`]: crate::chain::chainmonitor::ChainMonitor::get_claimable_balances
		last_local_balance_msat: Option<u64>,
	},
	/// Used to indicate to the user that they can abandon the funding transaction and recycle the
	/// inputs for another purpose.
	///
	/// This event is not guaranteed to be generated for channels that are closed due to a restart.
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`) and will be persisted across restarts.
	DiscardFunding {
		/// The channel_id of the channel which has been closed.
		channel_id: ChannelId,
		/// The full transaction received from the user
		funding_info: FundingInfo,
	},
	/// Indicates a request to open a new channel by a peer.
	///
	/// To accept the request (and in the case of a dual-funded channel, not contribute funds),
	/// call [`ChannelManager::accept_inbound_channel`].
	/// To reject the request, call [`ChannelManager::force_close_broadcasting_latest_txn`].
	/// Note that a ['ChannelClosed`] event will _not_ be triggered if the channel is rejected.
	///
	/// The event is only triggered when a new open channel request is received and the
	/// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true.
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`) and won't be persisted across restarts.
	///
	/// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
	/// [`ChannelManager::force_close_broadcasting_latest_txn`]: crate::ln::channelmanager::ChannelManager::force_close_broadcasting_latest_txn
	/// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
	OpenChannelRequest {
		/// The temporary channel ID of the channel requested to be opened.
		///
		/// When responding to the request, the `temporary_channel_id` should be passed
		/// back to the ChannelManager through [`ChannelManager::accept_inbound_channel`] to accept,
		/// or through [`ChannelManager::force_close_broadcasting_latest_txn`] to reject.
		///
		/// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
		/// [`ChannelManager::force_close_broadcasting_latest_txn`]: crate::ln::channelmanager::ChannelManager::force_close_broadcasting_latest_txn
		temporary_channel_id: ChannelId,
		/// The node_id of the counterparty requesting to open the channel.
		///
		/// When responding to the request, the `counterparty_node_id` should be passed
		/// back to the `ChannelManager` through [`ChannelManager::accept_inbound_channel`] to
		/// accept the request, or through [`ChannelManager::force_close_broadcasting_latest_txn`]
		/// to reject the request.
		///
		/// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
		/// [`ChannelManager::force_close_broadcasting_latest_txn`]: crate::ln::channelmanager::ChannelManager::force_close_broadcasting_latest_txn
		counterparty_node_id: PublicKey,
		/// The channel value of the requested channel.
		funding_satoshis: u64,
		/// If `channel_negotiation_type` is `InboundChannelFunds::DualFunded`, this indicates that the peer wishes to
		/// open a dual-funded channel. Otherwise, this field will be `InboundChannelFunds::PushMsats`,
		/// indicating the `push_msats` value our peer is pushing to us for a non-dual-funded channel.
		channel_negotiation_type: InboundChannelFunds,
		/// The features that this channel will operate with. If you reject the channel, a
		/// well-behaved counterparty may automatically re-attempt the channel with a new set of
		/// feature flags.
		///
		/// Note that if [`ChannelTypeFeatures::supports_scid_privacy`] returns true on this type,
		/// the resulting [`ChannelManager`] will not be readable by versions of LDK prior to
		/// 0.0.106.
		///
		/// Furthermore, note that if [`ChannelTypeFeatures::supports_zero_conf`] returns true on this type,
		/// the resulting [`ChannelManager`] will not be readable by versions of LDK prior to
		/// 0.0.107. Channels setting this type also need to get manually accepted via
		/// [`crate::ln::channelmanager::ChannelManager::accept_inbound_channel_from_trusted_peer_0conf`],
		/// or will be rejected otherwise.
		///
		/// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
		channel_type: ChannelTypeFeatures,
		/// True if this channel is (or will be) publicly-announced.
		is_announced: bool,
		/// Channel parameters given by the counterparty.
		params: msgs::ChannelParameters,
	},
	/// Indicates that the HTLC was accepted, but could not be processed when or after attempting to
	/// forward it.
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`) and will be persisted across restarts.
	HTLCHandlingFailed {
		/// The channel over which the HTLC was received.
		prev_channel_id: ChannelId,
		/// The type of HTLC handling that failed.
		failure_type: HTLCHandlingFailureType,
		/// The reason that the HTLC failed.
		///
		/// This field will be `None` only for objects serialized prior to LDK 0.2.0.
		failure_reason: Option<HTLCHandlingFailureReason>,
	},
	/// Indicates that a transaction originating from LDK needs to have its fee bumped. This event
	/// requires confirmed external funds to be readily available to spend.
	///
	/// LDK does not currently generate this event unless the
	/// [`ChannelHandshakeConfig::negotiate_anchors_zero_fee_htlc_tx`] config flag is set to true.
	/// It is limited to the scope of channels with anchor outputs.
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`), but will only be regenerated as needed after restarts.
	///
	/// [`ChannelHandshakeConfig::negotiate_anchors_zero_fee_htlc_tx`]: crate::util::config::ChannelHandshakeConfig::negotiate_anchors_zero_fee_htlc_tx
	BumpTransaction(BumpTransactionEvent),
	/// We received an onion message that is intended to be forwarded to a peer
	/// that is currently offline. This event will only be generated if the
	/// `OnionMessenger` was initialized with
	/// [`OnionMessenger::new_with_offline_peer_interception`], see its docs.
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`), but won't be persisted across restarts.
	///
	/// [`OnionMessenger::new_with_offline_peer_interception`]: crate::onion_message::messenger::OnionMessenger::new_with_offline_peer_interception
	OnionMessageIntercepted {
		/// The node id of the offline peer.
		peer_node_id: PublicKey,
		/// The onion message intended to be forwarded to `peer_node_id`.
		message: msgs::OnionMessage,
	},
	/// Indicates that an onion message supporting peer has come online and it may
	/// be time to forward any onion messages that were previously intercepted for
	/// them. This event will only be generated if the `OnionMessenger` was
	/// initialized with
	/// [`OnionMessenger::new_with_offline_peer_interception`], see its docs.
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`), but won't be persisted across restarts.
	///
	/// [`OnionMessenger::new_with_offline_peer_interception`]: crate::onion_message::messenger::OnionMessenger::new_with_offline_peer_interception
	OnionMessagePeerConnected {
		/// The node id of the peer we just connected to, who advertises support for
		/// onion messages.
		peer_node_id: PublicKey,
	},
	/// As a static invoice server, we received a [`StaticInvoice`] from an async recipient that wants
	/// us to serve the invoice to payers on their behalf when they are offline. This event will only
	/// be generated if we previously created paths using
	/// [`ChannelManager::blinded_paths_for_async_recipient`] and the recipient was configured with
	/// them via [`ChannelManager::set_paths_to_static_invoice_server`].
	///
	/// [`ChannelManager::blinded_paths_for_async_recipient`]: crate::ln::channelmanager::ChannelManager::blinded_paths_for_async_recipient
	/// [`ChannelManager::set_paths_to_static_invoice_server`]: crate::ln::channelmanager::ChannelManager::set_paths_to_static_invoice_server
	#[cfg(async_payments)]
	PersistStaticInvoice {
		/// The invoice that should be persisted and later provided to payers when handling a future
		/// [`Event::StaticInvoiceRequested`].
		invoice: StaticInvoice,
		/// Useful for the recipient to replace a specific invoice stored by us as the static invoice
		/// server.
		///
		/// When this invoice and its metadata are persisted, this slot number should be included so if
		/// we receive another [`Event::PersistStaticInvoice`] containing the same slot number we can
		/// swap the existing invoice out for the new one.
		invoice_slot: u16,
		/// An identifier for the recipient, originally provided to
		/// [`ChannelManager::blinded_paths_for_async_recipient`].
		///
		/// When an [`Event::StaticInvoiceRequested`] comes in for the invoice, this id will be surfaced
		/// and can be used alongside the `invoice_id` to retrieve the invoice from the database.
		recipient_id: Vec<u8>,
		/// A random identifier for the invoice. When an [`Event::StaticInvoiceRequested`] comes in for
		/// the invoice, this id will be surfaced and can be used alongside the `recipient_id` to
		/// retrieve the invoice from the database.
		///
		/// Note that this id will remain the same for all invoice updates corresponding to a particular
		/// offer that the recipient has cached.
		invoice_id: u128,
		/// Once the [`StaticInvoice`], `invoice_slot` and `invoice_id` are persisted,
		/// [`ChannelManager::static_invoice_persisted`] should be called with this responder to confirm
		/// to the recipient that their [`Offer`] is ready to be used for async payments.
		///
		/// [`ChannelManager::static_invoice_persisted`]: crate::ln::channelmanager::ChannelManager::static_invoice_persisted
		/// [`Offer`]: crate::offers::offer::Offer
		invoice_persisted_path: Responder,
	},
	/// As a static invoice server, we received an [`InvoiceRequest`] on behalf of an often-offline
	/// recipient for whom we are serving [`StaticInvoice`]s.
	///
	/// This event will only be generated if we previously created paths using
	/// [`ChannelManager::blinded_paths_for_async_recipient`] and the recipient was configured with
	/// them via [`ChannelManager::set_paths_to_static_invoice_server`].
	///
	/// If we previously persisted a [`StaticInvoice`] from an [`Event::PersistStaticInvoice`] that
	/// matches the below `recipient_id` and `invoice_id`, that invoice should be retrieved now
	/// and forwarded to the payer via [`ChannelManager::send_static_invoice`].
	///
	/// [`ChannelManager::blinded_paths_for_async_recipient`]: crate::ln::channelmanager::ChannelManager::blinded_paths_for_async_recipient
	/// [`ChannelManager::set_paths_to_static_invoice_server`]: crate::ln::channelmanager::ChannelManager::set_paths_to_static_invoice_server
	/// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
	/// [`ChannelManager::send_static_invoice`]: crate::ln::channelmanager::ChannelManager::send_static_invoice
	#[cfg(async_payments)]
	StaticInvoiceRequested {
		/// An identifier for the recipient previously surfaced in
		/// [`Event::PersistStaticInvoice::recipient_id`]. Useful when paired with the `invoice_id` to
		/// retrieve the [`StaticInvoice`] requested by the payer.
		recipient_id: Vec<u8>,
		/// A random identifier for the invoice being requested, previously surfaced in
		/// [`Event::PersistStaticInvoice::invoice_id`]. Useful when paired with the `recipient_id` to
		/// retrieve the [`StaticInvoice`] requested by the payer.
		invoice_id: u128,
		/// The path over which the [`StaticInvoice`] will be sent to the payer, which should be
		/// provided to [`ChannelManager::send_static_invoice`] along with the invoice.
		///
		/// [`ChannelManager::send_static_invoice`]: crate::ln::channelmanager::ChannelManager::send_static_invoice
		reply_path: Responder,
	},
	/// Indicates that a channel funding transaction constructed interactively is ready to be
	/// signed. This event will only be triggered if at least one input was contributed.
	///
	/// The transaction contains all inputs and outputs provided by both parties including the
	/// channel's funding output and a change output if applicable.
	///
	/// No part of the transaction should be changed before signing as the content of the transaction
	/// has already been negotiated with the counterparty.
	///
	/// Each signature MUST use the `SIGHASH_ALL` flag to avoid invalidation of the initial commitment and
	/// hence possible loss of funds.
	///
	/// After signing, call [`ChannelManager::funding_transaction_signed`] with the (partially) signed
	/// funding transaction.
	///
	/// Generated in [`ChannelManager`] message handling.
	///
	/// # Failure Behavior and Persistence
	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
	/// returning `Err(ReplayEvent ())`), but will only be regenerated as needed after restarts.
	///
	/// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
	/// [`ChannelManager::funding_transaction_signed`]: crate::ln::channelmanager::ChannelManager::funding_transaction_signed
	FundingTransactionReadyForSigning {
		/// The `channel_id` of the channel which you'll need to pass back into
		/// [`ChannelManager::funding_transaction_signed`].
		///
		/// [`ChannelManager::funding_transaction_signed`]: crate::ln::channelmanager::ChannelManager::funding_transaction_signed
		channel_id: ChannelId,
		/// The counterparty's `node_id`, which you'll need to pass back into
		/// [`ChannelManager::funding_transaction_signed`].
		///
		/// [`ChannelManager::funding_transaction_signed`]: crate::ln::channelmanager::ChannelManager::funding_transaction_signed
		counterparty_node_id: PublicKey,
		/// The `user_channel_id` value passed in for outbound channels, or for inbound channels if
		/// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true. Otherwise
		/// `user_channel_id` will be randomized for inbound channels.
		///
		/// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
		user_channel_id: u128,
		/// The unsigned transaction to be signed and passed back to
		/// [`ChannelManager::funding_transaction_signed`].
		///
		/// [`ChannelManager::funding_transaction_signed`]: crate::ln::channelmanager::ChannelManager::funding_transaction_signed
		unsigned_transaction: Transaction,
	},
}

impl Writeable for Event {
	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
		match self {
			&Event::FundingGenerationReady { .. } => {
				0u8.write(writer)?;
				// We never write out FundingGenerationReady events as, upon disconnection, peers
				// drop any channels which have not yet exchanged funding_signed.
			},
			&Event::PaymentClaimable {
				ref payment_hash,
				ref amount_msat,
				counterparty_skimmed_fee_msat,
				ref purpose,
				ref receiver_node_id,
				ref receiving_channel_ids,
				ref claim_deadline,
				ref onion_fields,
				ref payment_id,
			} => {
				1u8.write(writer)?;
				let mut payment_secret = None;
				let payment_preimage;
				let mut payment_context = None;
				match &purpose {
					PaymentPurpose::Bolt11InvoicePayment {
						payment_preimage: preimage,
						payment_secret: secret,
					} => {
						payment_secret = Some(secret);
						payment_preimage = *preimage;
					},
					PaymentPurpose::Bolt12OfferPayment {
						payment_preimage: preimage,
						payment_secret: secret,
						payment_context: context,
					} => {
						payment_secret = Some(secret);
						payment_preimage = *preimage;
						payment_context = Some(PaymentContextRef::Bolt12Offer(context));
					},
					PaymentPurpose::Bolt12RefundPayment {
						payment_preimage: preimage,
						payment_secret: secret,
						payment_context: context,
					} => {
						payment_secret = Some(secret);
						payment_preimage = *preimage;
						payment_context = Some(PaymentContextRef::Bolt12Refund(context));
					},
					PaymentPurpose::SpontaneousPayment(preimage) => {
						payment_preimage = Some(*preimage);
					},
				}
				let skimmed_fee_opt = if counterparty_skimmed_fee_msat == 0 {
					None
				} else {
					Some(counterparty_skimmed_fee_msat)
				};

				let (receiving_channel_id_legacy, receiving_user_channel_id_legacy) =
					match receiving_channel_ids.last() {
						Some((chan_id, user_chan_id)) => (Some(*chan_id), *user_chan_id),
						None => (None, None),
					};
				write_tlv_fields!(writer, {
					(0, payment_hash, required),
					(1, receiver_node_id, option),
					(2, payment_secret, option),
					// Marked as legacy in version 0.2.0; superseded by `receiving_channel_ids`,
					// which includes all channel IDs used in the payment instead of only the last
					// one.
					(3, receiving_channel_id_legacy, option),
					(4, amount_msat, required),
					// Marked as legacy in version 0.2.0 for the same reason as
					// `receiving_channel_id_legacy`; superseded by `receiving_channel_ids`.
					(5, receiving_user_channel_id_legacy, option),
					// Type 6 was `user_payment_id` on 0.0.103 and earlier
					(7, claim_deadline, option),
					(8, payment_preimage, option),
					(9, onion_fields, option),
					(10, skimmed_fee_opt, option),
					(11, payment_context, option),
					(13, payment_id, option),
					(15, *receiving_channel_ids, optional_vec),
				});
			},
			&Event::PaymentSent {
				ref payment_id,
				ref payment_preimage,
				ref payment_hash,
				ref amount_msat,
				ref fee_paid_msat,
				ref bolt12_invoice,
			} => {
				2u8.write(writer)?;
				write_tlv_fields!(writer, {
					(0, payment_preimage, required),
					(1, payment_hash, required),
					(3, payment_id, option),
					(5, fee_paid_msat, option),
					(7, amount_msat, option),
					(9, bolt12_invoice, option),
				});
			},
			&Event::PaymentPathFailed {
				ref payment_id,
				ref payment_hash,
				ref payment_failed_permanently,
				ref failure,
				ref path,
				ref short_channel_id,
				#[cfg(any(test, feature = "_test_utils"))]
				ref error_code,
				#[cfg(any(test, feature = "_test_utils"))]
				ref error_data,
				ref hold_times,
			} => {
				3u8.write(writer)?;
				#[cfg(any(test, feature = "_test_utils"))]
				error_code.write(writer)?;
				#[cfg(any(test, feature = "_test_utils"))]
				error_data.write(writer)?;
				write_tlv_fields!(writer, {
					(0, payment_hash, required),
					(1, None::<NetworkUpdate>, option), // network_update in LDK versions prior to 0.0.114
					(2, payment_failed_permanently, required),
					(3, false, required), // all_paths_failed in LDK versions prior to 0.0.114
					(4, path.blinded_tail, option),
					(5, path.hops, required_vec),
					(7, short_channel_id, option),
					(9, None::<RouteParameters>, option), // retry in LDK versions prior to 0.0.115
					(11, payment_id, option),
					(13, failure, required),
					(15, *hold_times, optional_vec),
				});
			},
			// 4u8 used to be `PendingHTLCsForwardable`
			&Event::SpendableOutputs { ref outputs, channel_id } => {
				5u8.write(writer)?;
				write_tlv_fields!(writer, {
					(0, WithoutLength(outputs), required),
					(1, channel_id, option),
				});
			},
			&Event::HTLCIntercepted {
				requested_next_hop_scid,
				payment_hash,
				inbound_amount_msat,
				expected_outbound_amount_msat,
				intercept_id,
			} => {
				6u8.write(writer)?;
				let intercept_scid = InterceptNextHop::FakeScid { requested_next_hop_scid };
				write_tlv_fields!(writer, {
					(0, intercept_id, required),
					(2, intercept_scid, required),
					(4, payment_hash, required),
					(6, inbound_amount_msat, required),
					(8, expected_outbound_amount_msat, required),
				});
			},
			&Event::PaymentForwarded {
				prev_channel_id,
				next_channel_id,
				prev_user_channel_id,
				next_user_channel_id,
				prev_node_id,
				next_node_id,
				total_fee_earned_msat,
				skimmed_fee_msat,
				claim_from_onchain_tx,
				outbound_amount_forwarded_msat,
			} => {
				7u8.write(writer)?;
				write_tlv_fields!(writer, {
					(0, total_fee_earned_msat, option),
					(1, prev_channel_id, option),
					(2, claim_from_onchain_tx, required),
					(3, next_channel_id, option),
					(5, outbound_amount_forwarded_msat, option),
					(7, skimmed_fee_msat, option),
					(9, prev_user_channel_id, option),
					(11, next_user_channel_id, option),
					(13, prev_node_id, option),
					(15, next_node_id, option),
				});
			},
			&Event::ChannelClosed {
				ref channel_id,
				ref user_channel_id,
				ref reason,
				ref counterparty_node_id,
				ref channel_capacity_sats,
				ref channel_funding_txo,
				ref last_local_balance_msat,
			} => {
				9u8.write(writer)?;
				// `user_channel_id` used to be a single u64 value. In order to remain backwards
				// compatible with versions prior to 0.0.113, the u128 is serialized as two
				// separate u64 values.
				let user_channel_id_low = *user_channel_id as u64;
				let user_channel_id_high = (*user_channel_id >> 64) as u64;
				write_tlv_fields!(writer, {
					(0, channel_id, required),
					(1, user_channel_id_low, required),
					(2, reason, required),
					(3, user_channel_id_high, required),
					(5, counterparty_node_id, option),
					(7, channel_capacity_sats, option),
					(9, channel_funding_txo, option),
					(11, last_local_balance_msat, option)
				});
			},
			&Event::DiscardFunding { ref channel_id, ref funding_info } => {
				11u8.write(writer)?;

				let transaction = if let FundingInfo::Tx { transaction } = funding_info {
					Some(transaction)
				} else {
					None
				};
				write_tlv_fields!(writer, {
					(0, channel_id, required),
					(2, transaction, option),
					(4, funding_info, required),
				})
			},
			&Event::PaymentPathSuccessful {
				ref payment_id,
				ref payment_hash,
				ref path,
				ref hold_times,
			} => {
				13u8.write(writer)?;
				write_tlv_fields!(writer, {
					(0, payment_id, required),
					(1, *hold_times, optional_vec),
					(2, payment_hash, option),
					(4, path.hops, required_vec),
					(6, path.blinded_tail, option),
				})
			},
			&Event::PaymentFailed { ref payment_id, ref payment_hash, ref reason } => {
				15u8.write(writer)?;
				let (payment_hash, invoice_received) = match payment_hash {
					Some(payment_hash) => (payment_hash, true),
					None => (&PaymentHash([0; 32]), false),
				};
				let legacy_reason = match reason {
					None => &None,
					// Variants available prior to version 0.0.124.
					Some(PaymentFailureReason::RecipientRejected)
					| Some(PaymentFailureReason::UserAbandoned)
					| Some(PaymentFailureReason::RetriesExhausted)
					| Some(PaymentFailureReason::PaymentExpired)
					| Some(PaymentFailureReason::RouteNotFound)
					| Some(PaymentFailureReason::UnexpectedError) => reason,
					// Variants introduced at version 0.0.124 or later. Prior versions fail to parse
					// unknown variants, while versions 0.0.124 or later will use None.
					Some(PaymentFailureReason::UnknownRequiredFeatures) => {
						&Some(PaymentFailureReason::RecipientRejected)
					},
					Some(PaymentFailureReason::InvoiceRequestExpired) => {
						&Some(PaymentFailureReason::RetriesExhausted)
					},
					Some(PaymentFailureReason::InvoiceRequestRejected) => {
						&Some(PaymentFailureReason::RecipientRejected)
					},
					Some(PaymentFailureReason::BlindedPathCreationFailed) => {
						&Some(PaymentFailureReason::RouteNotFound)
					},
				};
				write_tlv_fields!(writer, {
					(0, payment_id, required),
					(1, legacy_reason, option),
					(2, payment_hash, required),
					(3, invoice_received, required),
					(5, reason, option),
				})
			},
			&Event::OpenChannelRequest { .. } => {
				17u8.write(writer)?;
				// We never write the OpenChannelRequest events as, upon disconnection, peers
				// drop any channels which have not yet exchanged funding_signed.
			},
			&Event::PaymentClaimed {
				ref payment_hash,
				ref amount_msat,
				ref purpose,
				ref receiver_node_id,
				ref htlcs,
				ref sender_intended_total_msat,
				ref onion_fields,
				ref payment_id,
			} => {
				19u8.write(writer)?;
				write_tlv_fields!(writer, {
					(0, payment_hash, required),
					(1, receiver_node_id, option),
					(2, purpose, required),
					(4, amount_msat, required),
					(5, *htlcs, optional_vec),
					(7, sender_intended_total_msat, option),
					(9, onion_fields, option),
					(11, payment_id, option),
				});
			},
			&Event::ProbeSuccessful { ref payment_id, ref payment_hash, ref path } => {
				21u8.write(writer)?;
				write_tlv_fields!(writer, {
					(0, payment_id, required),
					(2, payment_hash, required),
					(4, path.hops, required_vec),
					(6, path.blinded_tail, option),
				})
			},
			&Event::ProbeFailed {
				ref payment_id,
				ref payment_hash,
				ref path,
				ref short_channel_id,
			} => {
				23u8.write(writer)?;
				write_tlv_fields!(writer, {
					(0, payment_id, required),
					(2, payment_hash, required),
					(4, path.hops, required_vec),
					(6, short_channel_id, option),
					(8, path.blinded_tail, option),
				})
			},
			&Event::HTLCHandlingFailed {
				ref prev_channel_id,
				ref failure_type,
				ref failure_reason,
			} => {
				25u8.write(writer)?;
				write_tlv_fields!(writer, {
					(0, prev_channel_id, required),
					(1, failure_reason, option),
					(2, failure_type, required),
				})
			},
			&Event::BumpTransaction(ref event) => {
				27u8.write(writer)?;
				match event {
					// We never write the ChannelClose|HTLCResolution events as they'll be replayed
					// upon restarting anyway if they remain unresolved.
					BumpTransactionEvent::ChannelClose { .. } => {},
					BumpTransactionEvent::HTLCResolution { .. } => {},
				}
				write_tlv_fields!(writer, {}); // Write a length field for forwards compat
			},
			&Event::ChannelReady {
				ref channel_id,
				ref user_channel_id,
				ref counterparty_node_id,
				ref funding_txo,
				ref channel_type,
			} => {
				29u8.write(writer)?;
				write_tlv_fields!(writer, {
					(0, channel_id, required),
					(1, funding_txo, option),
					(2, user_channel_id, required),
					(4, counterparty_node_id, required),
					(6, channel_type, required),
				});
			},
			&Event::ChannelPending {
				ref channel_id,
				ref user_channel_id,
				ref former_temporary_channel_id,
				ref counterparty_node_id,
				ref funding_txo,
				ref channel_type,
			} => {
				31u8.write(writer)?;
				write_tlv_fields!(writer, {
					(0, channel_id, required),
					(1, channel_type, option),
					(2, user_channel_id, required),
					(4, former_temporary_channel_id, required),
					(6, counterparty_node_id, required),
					(8, funding_txo, required),
				});
			},
			&Event::ConnectionNeeded { .. } => {
				35u8.write(writer)?;
				// Never write ConnectionNeeded events as buffered onion messages aren't serialized.
			},
			&Event::OnionMessageIntercepted { ref peer_node_id, ref message } => {
				37u8.write(writer)?;
				write_tlv_fields!(writer, {
					(0, peer_node_id, required),
					(2, message, required),
				});
			},
			&Event::OnionMessagePeerConnected { ref peer_node_id } => {
				39u8.write(writer)?;
				write_tlv_fields!(writer, {
					(0, peer_node_id, required),
				});
			},
			&Event::InvoiceReceived { ref payment_id, ref invoice, ref context, ref responder } => {
				41u8.write(writer)?;
				write_tlv_fields!(writer, {
					(0, payment_id, required),
					(2, invoice, required),
					(4, context, option),
					(6, responder, option),
				});
			},
			&Event::FundingTxBroadcastSafe {
				ref channel_id,
				ref user_channel_id,
				ref funding_txo,
				ref counterparty_node_id,
				ref former_temporary_channel_id,
			} => {
				43u8.write(writer)?;
				write_tlv_fields!(writer, {
					(0, channel_id, required),
					(2, user_channel_id, required),
					(4, funding_txo, required),
					(6, counterparty_node_id, required),
					(8, former_temporary_channel_id, required),
				});
			},
			#[cfg(async_payments)]
			&Event::PersistStaticInvoice { .. } => {
				45u8.write(writer)?;
				// No need to write these events because we can just restart the static invoice negotiation
				// on startup.
			},
			#[cfg(async_payments)]
			&Event::StaticInvoiceRequested { .. } => {
				47u8.write(writer)?;
				// Never write StaticInvoiceRequested events as buffered onion messages aren't serialized.
			},
			&Event::FundingTransactionReadyForSigning { .. } => {
				49u8.write(writer)?;
				// We never write out FundingTransactionReadyForSigning events as they will be regenerated when
				// necessary.
			},
			// Note that, going forward, all new events must only write data inside of
			// `write_tlv_fields`. Versions 0.0.101+ will ignore odd-numbered events that write
			// data via `write_tlv_fields`.
		}
		Ok(())
	}
}
impl MaybeReadable for Event {
	fn read<R: io::Read>(reader: &mut R) -> Result<Option<Self>, msgs::DecodeError> {
		match Readable::read(reader)? {
			// Note that we do not write a length-prefixed TLV for FundingGenerationReady events.
			0u8 => Ok(None),
			1u8 => {
				let mut f = || {
					let mut payment_hash = PaymentHash([0; 32]);
					let mut payment_preimage = None;
					let mut payment_secret = None;
					let mut amount_msat = 0;
					let mut counterparty_skimmed_fee_msat_opt = None;
					let mut receiver_node_id = None;
					let mut _user_payment_id = None::<u64>; // Used in 0.0.103 and earlier, no longer written in 0.0.116+.
					let mut receiving_channel_id_legacy = None;
					let mut claim_deadline = None;
					let mut receiving_user_channel_id_legacy = None;
					let mut onion_fields = None;
					let mut payment_context = None;
					let mut payment_id = None;
					let mut receiving_channel_ids_opt = None;
					read_tlv_fields!(reader, {
						(0, payment_hash, required),
						(1, receiver_node_id, option),
						(2, payment_secret, option),
						(3, receiving_channel_id_legacy, option),
						(4, amount_msat, required),
						(5, receiving_user_channel_id_legacy, option),
						(6, _user_payment_id, option),
						(7, claim_deadline, option),
						(8, payment_preimage, option),
						(9, onion_fields, option),
						(10, counterparty_skimmed_fee_msat_opt, option),
						(11, payment_context, option),
						(13, payment_id, option),
						(15, receiving_channel_ids_opt, optional_vec),
					});
					let purpose = match payment_secret {
						Some(secret) => {
							PaymentPurpose::from_parts(payment_preimage, secret, payment_context)
								.map_err(|()| msgs::DecodeError::InvalidValue)?
						},
						None if payment_preimage.is_some() => {
							PaymentPurpose::SpontaneousPayment(payment_preimage.unwrap())
						},
						None => return Err(msgs::DecodeError::InvalidValue),
					};

					let receiving_channel_ids = receiving_channel_ids_opt
						.or_else(|| {
							receiving_channel_id_legacy
								.map(|chan_id| vec![(chan_id, receiving_user_channel_id_legacy)])
						})
						.unwrap_or_default();

					Ok(Some(Event::PaymentClaimable {
						receiver_node_id,
						payment_hash,
						amount_msat,
						counterparty_skimmed_fee_msat: counterparty_skimmed_fee_msat_opt
							.unwrap_or(0),
						purpose,
						receiving_channel_ids,
						claim_deadline,
						onion_fields,
						payment_id,
					}))
				};
				f()
			},
			2u8 => {
				let mut f = || {
					let mut payment_preimage = PaymentPreimage([0; 32]);
					let mut payment_hash = None;
					let mut payment_id = None;
					let mut amount_msat = None;
					let mut fee_paid_msat = None;
					let mut bolt12_invoice = None;
					read_tlv_fields!(reader, {
						(0, payment_preimage, required),
						(1, payment_hash, option),
						(3, payment_id, option),
						(5, fee_paid_msat, option),
						(7, amount_msat, option),
						(9, bolt12_invoice, option),
					});
					if payment_hash.is_none() {
						payment_hash = Some(PaymentHash(
							Sha256::hash(&payment_preimage.0[..]).to_byte_array(),
						));
					}
					Ok(Some(Event::PaymentSent {
						payment_id,
						payment_preimage,
						payment_hash: payment_hash.unwrap(),
						amount_msat,
						fee_paid_msat,
						bolt12_invoice,
					}))
				};
				f()
			},
			3u8 => {
				let mut f = || {
					#[cfg(any(test, feature = "_test_utils"))]
					let error_code = Readable::read(reader)?;
					#[cfg(any(test, feature = "_test_utils"))]
					let error_data = Readable::read(reader)?;
					let mut payment_hash = PaymentHash([0; 32]);
					let mut payment_failed_permanently = false;
					let mut network_update = None;
					let mut blinded_tail: Option<BlindedTail> = None;
					let mut path: Option<Vec<RouteHop>> = Some(vec![]);
					let mut short_channel_id = None;
					let mut payment_id = None;
					let mut failure_opt = None;
					let mut hold_times = None;
					read_tlv_fields!(reader, {
						(0, payment_hash, required),
						(1, network_update, upgradable_option),
						(2, payment_failed_permanently, required),
						(4, blinded_tail, option),
						// Added as a part of LDK 0.0.101 and always filled in since.
						// Defaults to an empty Vec, though likely should have been `Option`al.
						(5, path, optional_vec),
						(7, short_channel_id, option),
						(11, payment_id, option),
						(13, failure_opt, upgradable_option),
						(15, hold_times, optional_vec),
					});
					let hold_times = hold_times.unwrap_or(Vec::new());
					let failure =
						failure_opt.unwrap_or_else(|| PathFailure::OnPath { network_update });
					Ok(Some(Event::PaymentPathFailed {
						payment_id,
						payment_hash,
						payment_failed_permanently,
						failure,
						path: Path { hops: path.unwrap(), blinded_tail },
						short_channel_id,
						#[cfg(any(test, feature = "_test_utils"))]
						error_code,
						#[cfg(any(test, feature = "_test_utils"))]
						error_data,
						hold_times,
					}))
				};
				f()
			},
			4u8 => Ok(None),
			5u8 => {
				let mut f = || {
					let mut outputs = WithoutLength(Vec::new());
					let mut channel_id: Option<ChannelId> = None;
					read_tlv_fields!(reader, {
						(0, outputs, required),
						(1, channel_id, option),
					});
					Ok(Some(Event::SpendableOutputs { outputs: outputs.0, channel_id }))
				};
				f()
			},
			6u8 => {
				let mut payment_hash = PaymentHash([0; 32]);
				let mut intercept_id = InterceptId([0; 32]);
				let mut requested_next_hop_scid =
					InterceptNextHop::FakeScid { requested_next_hop_scid: 0 };
				let mut inbound_amount_msat = 0;
				let mut expected_outbound_amount_msat = 0;
				read_tlv_fields!(reader, {
					(0, intercept_id, required),
					(2, requested_next_hop_scid, required),
					(4, payment_hash, required),
					(6, inbound_amount_msat, required),
					(8, expected_outbound_amount_msat, required),
				});
				let next_scid = match requested_next_hop_scid {
					InterceptNextHop::FakeScid { requested_next_hop_scid: scid } => scid,
				};
				Ok(Some(Event::HTLCIntercepted {
					payment_hash,
					requested_next_hop_scid: next_scid,
					inbound_amount_msat,
					expected_outbound_amount_msat,
					intercept_id,
				}))
			},
			7u8 => {
				let mut f = || {
					let mut prev_channel_id = None;
					let mut next_channel_id = None;
					let mut prev_user_channel_id = None;
					let mut next_user_channel_id = None;
					let mut prev_node_id = None;
					let mut next_node_id = None;
					let mut total_fee_earned_msat = None;
					let mut skimmed_fee_msat = None;
					let mut claim_from_onchain_tx = false;
					let mut outbound_amount_forwarded_msat = None;
					read_tlv_fields!(reader, {
						(0, total_fee_earned_msat, option),
						(1, prev_channel_id, option),
						(2, claim_from_onchain_tx, required),
						(3, next_channel_id, option),
						(5, outbound_amount_forwarded_msat, option),
						(7, skimmed_fee_msat, option),
						(9, prev_user_channel_id, option),
						(11, next_user_channel_id, option),
						(13, prev_node_id, option),
						(15, next_node_id, option),
					});
					Ok(Some(Event::PaymentForwarded {
						prev_channel_id,
						next_channel_id,
						prev_user_channel_id,
						next_user_channel_id,
						prev_node_id,
						next_node_id,
						total_fee_earned_msat,
						skimmed_fee_msat,
						claim_from_onchain_tx,
						outbound_amount_forwarded_msat,
					}))
				};
				f()
			},
			9u8 => {
				let mut f = || {
					let mut channel_id = ChannelId::new_zero();
					let mut reason = UpgradableRequired(None);
					let mut user_channel_id_low_opt: Option<u64> = None;
					let mut user_channel_id_high_opt: Option<u64> = None;
					let mut counterparty_node_id = None;
					let mut channel_capacity_sats = None;
					let mut channel_funding_txo = None;
					let mut last_local_balance_msat = None;
					read_tlv_fields!(reader, {
						(0, channel_id, required),
						(1, user_channel_id_low_opt, option),
						(2, reason, upgradable_required),
						(3, user_channel_id_high_opt, option),
						(5, counterparty_node_id, option),
						(7, channel_capacity_sats, option),
						(9, channel_funding_txo, option),
						(11, last_local_balance_msat, option)
					});

					// `user_channel_id` used to be a single u64 value. In order to remain
					// backwards compatible with versions prior to 0.0.113, the u128 is serialized
					// as two separate u64 values.
					let user_channel_id = (user_channel_id_low_opt.unwrap_or(0) as u128)
						+ ((user_channel_id_high_opt.unwrap_or(0) as u128) << 64);

					Ok(Some(Event::ChannelClosed {
						channel_id,
						user_channel_id,
						reason: _init_tlv_based_struct_field!(reason, upgradable_required),
						counterparty_node_id,
						channel_capacity_sats,
						channel_funding_txo,
						last_local_balance_msat,
					}))
				};
				f()
			},
			11u8 => {
				let mut f = || {
					let mut channel_id = ChannelId::new_zero();
					let mut transaction: Option<Transaction> = None;
					let mut funding_info: Option<FundingInfo> = None;
					read_tlv_fields!(reader, {
						(0, channel_id, required),
						(2, transaction, option),
						(4, funding_info, option),
					});

					let funding_info = if let Some(tx) = transaction {
						FundingInfo::Tx { transaction: tx }
					} else {
						funding_info.ok_or(msgs::DecodeError::InvalidValue)?
					};
					Ok(Some(Event::DiscardFunding { channel_id, funding_info }))
				};
				f()
			},
			13u8 => {
				let mut f = || {
					_init_and_read_len_prefixed_tlv_fields!(reader, {
						(0, payment_id, required),
						(1, hold_times, optional_vec),
						(2, payment_hash, option),
						(4, path, required_vec),
						(6, blinded_tail, option),
					});

					let hold_times = hold_times.unwrap_or(Vec::new());

					Ok(Some(Event::PaymentPathSuccessful {
						payment_id: payment_id.0.unwrap(),
						payment_hash,
						path: Path { hops: path, blinded_tail },
						hold_times,
					}))
				};
				f()
			},
			15u8 => {
				let mut f = || {
					let mut payment_hash = PaymentHash([0; 32]);
					let mut payment_id = PaymentId([0; 32]);
					let mut reason = None;
					let mut legacy_reason = None;
					let mut invoice_received: Option<bool> = None;
					read_tlv_fields!(reader, {
						(0, payment_id, required),
						(1, legacy_reason, upgradable_option),
						(2, payment_hash, required),
						(3, invoice_received, option),
						(5, reason, upgradable_option),
					});
					let payment_hash = match invoice_received {
						Some(invoice_received) => invoice_received.then(|| payment_hash),
						None => (payment_hash != PaymentHash([0; 32])).then(|| payment_hash),
					};
					let reason = reason.or(legacy_reason);
					Ok(Some(Event::PaymentFailed {
						payment_id,
						payment_hash,
						reason: _init_tlv_based_struct_field!(reason, upgradable_option),
					}))
				};
				f()
			},
			17u8 => {
				// Value 17 is used for `Event::OpenChannelRequest`.
				Ok(None)
			},
			19u8 => {
				let mut f = || {
					let mut payment_hash = PaymentHash([0; 32]);
					let mut purpose = UpgradableRequired(None);
					let mut amount_msat = 0;
					let mut receiver_node_id = None;
					let mut htlcs: Option<Vec<ClaimedHTLC>> = Some(vec![]);
					let mut sender_intended_total_msat: Option<u64> = None;
					let mut onion_fields = None;
					let mut payment_id = None;
					read_tlv_fields!(reader, {
						(0, payment_hash, required),
						(1, receiver_node_id, option),
						(2, purpose, upgradable_required),
						(4, amount_msat, required),
						(5, htlcs, optional_vec),
						(7, sender_intended_total_msat, option),
						(9, onion_fields, option),
						(11, payment_id, option),
					});
					Ok(Some(Event::PaymentClaimed {
						receiver_node_id,
						payment_hash,
						purpose: _init_tlv_based_struct_field!(purpose, upgradable_required),
						amount_msat,
						htlcs: htlcs.unwrap_or_default(),
						sender_intended_total_msat,
						onion_fields,
						payment_id,
					}))
				};
				f()
			},
			21u8 => {
				let mut f = || {
					_init_and_read_len_prefixed_tlv_fields!(reader, {
						(0, payment_id, required),
						(2, payment_hash, required),
						(4, path, required_vec),
						(6, blinded_tail, option),
					});
					Ok(Some(Event::ProbeSuccessful {
						payment_id: payment_id.0.unwrap(),
						payment_hash: payment_hash.0.unwrap(),
						path: Path { hops: path, blinded_tail },
					}))
				};
				f()
			},
			23u8 => {
				let mut f = || {
					_init_and_read_len_prefixed_tlv_fields!(reader, {
						(0, payment_id, required),
						(2, payment_hash, required),
						(4, path, required_vec),
						(6, short_channel_id, option),
						(8, blinded_tail, option),
					});
					Ok(Some(Event::ProbeFailed {
						payment_id: payment_id.0.unwrap(),
						payment_hash: payment_hash.0.unwrap(),
						path: Path { hops: path, blinded_tail },
						short_channel_id,
					}))
				};
				f()
			},
			25u8 => {
				let mut f = || {
					let mut prev_channel_id = ChannelId::new_zero();
					let mut failure_reason = None;
					let mut failure_type_opt = UpgradableRequired(None);
					read_tlv_fields!(reader, {
						(0, prev_channel_id, required),
						(1, failure_reason, option),
						(2, failure_type_opt, upgradable_required),
					});

					// If a legacy HTLCHandlingFailureType::UnknownNextHop was written, upgrade
					// it to its new representation, otherwise leave unchanged.
					if let Some(HTLCHandlingFailureType::UnknownNextHop {
						requested_forward_scid,
					}) = failure_type_opt.0
					{
						failure_type_opt.0 = Some(HTLCHandlingFailureType::InvalidForward {
							requested_forward_scid,
						});
						failure_reason = Some(LocalHTLCFailureReason::UnknownNextPeer.into());
					}
					Ok(Some(Event::HTLCHandlingFailed {
						prev_channel_id,
						failure_type: _init_tlv_based_struct_field!(
							failure_type_opt,
							upgradable_required
						),
						failure_reason,
					}))
				};
				f()
			},
			27u8 => Ok(None),
			29u8 => {
				let mut f = || {
					let mut channel_id = ChannelId::new_zero();
					let mut user_channel_id: u128 = 0;
					let mut counterparty_node_id = RequiredWrapper(None);
					let mut funding_txo = None;
					let mut channel_type = RequiredWrapper(None);
					read_tlv_fields!(reader, {
						(0, channel_id, required),
						(1, funding_txo, option),
						(2, user_channel_id, required),
						(4, counterparty_node_id, required),
						(6, channel_type, required),
					});

					Ok(Some(Event::ChannelReady {
						channel_id,
						user_channel_id,
						counterparty_node_id: counterparty_node_id.0.unwrap(),
						funding_txo,
						channel_type: channel_type.0.unwrap(),
					}))
				};
				f()
			},
			31u8 => {
				let mut f = || {
					let mut channel_id = ChannelId::new_zero();
					let mut user_channel_id: u128 = 0;
					let mut former_temporary_channel_id = None;
					let mut counterparty_node_id = RequiredWrapper(None);
					let mut funding_txo = RequiredWrapper(None);
					let mut channel_type = None;
					read_tlv_fields!(reader, {
						(0, channel_id, required),
						(1, channel_type, option),
						(2, user_channel_id, required),
						(4, former_temporary_channel_id, required),
						(6, counterparty_node_id, required),
						(8, funding_txo, required),
					});

					Ok(Some(Event::ChannelPending {
						channel_id,
						user_channel_id,
						former_temporary_channel_id,
						counterparty_node_id: counterparty_node_id.0.unwrap(),
						funding_txo: funding_txo.0.unwrap(),
						channel_type,
					}))
				};
				f()
			},
			// This was Event::InvoiceRequestFailed prior to version 0.0.124.
			33u8 => {
				let mut f = || {
					_init_and_read_len_prefixed_tlv_fields!(reader, {
						(0, payment_id, required),
					});
					Ok(Some(Event::PaymentFailed {
						payment_id: payment_id.0.unwrap(),
						payment_hash: None,
						reason: Some(PaymentFailureReason::InvoiceRequestExpired),
					}))
				};
				f()
			},
			// Note that we do not write a length-prefixed TLV for ConnectionNeeded events.
			35u8 => Ok(None),
			37u8 => {
				let mut f = || {
					_init_and_read_len_prefixed_tlv_fields!(reader, {
						(0, peer_node_id, required),
						(2, message, required),
					});
					Ok(Some(Event::OnionMessageIntercepted {
						peer_node_id: peer_node_id.0.unwrap(),
						message: message.0.unwrap(),
					}))
				};
				f()
			},
			39u8 => {
				let mut f = || {
					_init_and_read_len_prefixed_tlv_fields!(reader, {
						(0, peer_node_id, required),
					});
					Ok(Some(Event::OnionMessagePeerConnected {
						peer_node_id: peer_node_id.0.unwrap(),
					}))
				};
				f()
			},
			41u8 => {
				let mut f = || {
					_init_and_read_len_prefixed_tlv_fields!(reader, {
						(0, payment_id, required),
						(2, invoice, required),
						(4, context, option),
						(6, responder, option),
					});
					Ok(Some(Event::InvoiceReceived {
						payment_id: payment_id.0.unwrap(),
						invoice: invoice.0.unwrap(),
						context,
						responder,
					}))
				};
				f()
			},
			43u8 => {
				let mut channel_id = RequiredWrapper(None);
				let mut user_channel_id = RequiredWrapper(None);
				let mut funding_txo = RequiredWrapper(None);
				let mut counterparty_node_id = RequiredWrapper(None);
				let mut former_temporary_channel_id = RequiredWrapper(None);
				read_tlv_fields!(reader, {
					(0, channel_id, required),
					(2, user_channel_id, required),
					(4, funding_txo, required),
					(6, counterparty_node_id, required),
					(8, former_temporary_channel_id, required)
				});
				Ok(Some(Event::FundingTxBroadcastSafe {
					channel_id: channel_id.0.unwrap(),
					user_channel_id: user_channel_id.0.unwrap(),
					funding_txo: funding_txo.0.unwrap(),
					counterparty_node_id: counterparty_node_id.0.unwrap(),
					former_temporary_channel_id: former_temporary_channel_id.0.unwrap(),
				}))
			},
			// Note that we do not write a length-prefixed TLV for PersistStaticInvoice events.
			#[cfg(async_payments)]
			45u8 => Ok(None),
			// Note that we do not write a length-prefixed TLV for StaticInvoiceRequested events.
			#[cfg(async_payments)]
			47u8 => Ok(None),
			// Note that we do not write a length-prefixed TLV for FundingTransactionReadyForSigning events.
			49u8 => Ok(None),
			// Versions prior to 0.0.100 did not ignore odd types, instead returning InvalidValue.
			// Version 0.0.100 failed to properly ignore odd types, possibly resulting in corrupt
			// reads.
			x if x % 2 == 1 => {
				// If the event is of unknown type, assume it was written with `write_tlv_fields`,
				// which prefixes the whole thing with a length BigSize. Because the event is
				// odd-type unknown, we should treat it as `Ok(None)` even if it has some TLV
				// fields that are even. Thus, we avoid using `read_tlv_fields` and simply read
				// exactly the number of bytes specified, ignoring them entirely.
				let tlv_len: BigSize = Readable::read(reader)?;
				FixedLengthReader::new(reader, tlv_len.0)
					.eat_remaining()
					.map_err(|_| msgs::DecodeError::ShortRead)?;
				Ok(None)
			},
			_ => Err(msgs::DecodeError::InvalidValue),
		}
	}
}

/// A trait indicating an object may generate events.
///
/// Events are processed by passing an [`EventHandler`] to [`process_pending_events`].
///
/// Implementations of this trait may also feature an async version of event handling, as shown with
/// [`ChannelManager::process_pending_events_async`] and
/// [`ChainMonitor::process_pending_events_async`].
///
/// # Requirements
///
/// When using this trait, [`process_pending_events`] will call [`handle_event`] for each pending
/// event since the last invocation.
///
/// In order to ensure no [`Event`]s are lost, implementors of this trait will persist [`Event`]s
/// and replay any unhandled events on startup. An [`Event`] is considered handled when
/// [`process_pending_events`] returns `Ok(())`, thus handlers MUST fully handle [`Event`]s and
/// persist any relevant changes to disk *before* returning `Ok(())`. In case of an error (e.g.,
/// persistence failure) implementors should return `Err(ReplayEvent())`, signalling to the
/// [`EventsProvider`] to replay unhandled events on the next invocation (generally immediately).
/// Note that some events might not be replayed, please refer to the documentation for
/// the individual [`Event`] variants for more detail.
///
/// Further, because an application may crash between an [`Event`] being handled and the
/// implementor of this trait being re-serialized, [`Event`] handling must be idempotent - in
/// effect, [`Event`]s may be replayed.
///
/// Note, handlers may call back into the provider and thus deadlocking must be avoided. Be sure to
/// consult the provider's documentation on the implication of processing events and how a handler
/// may safely use the provider (e.g., see [`ChannelManager::process_pending_events`] and
/// [`ChainMonitor::process_pending_events`]).
///
/// (C-not implementable) As there is likely no reason for a user to implement this trait on their
/// own type(s).
///
/// [`process_pending_events`]: Self::process_pending_events
/// [`handle_event`]: EventHandler::handle_event
/// [`ChannelManager::process_pending_events`]: crate::ln::channelmanager::ChannelManager#method.process_pending_events
/// [`ChainMonitor::process_pending_events`]: crate::chain::chainmonitor::ChainMonitor#method.process_pending_events
/// [`ChannelManager::process_pending_events_async`]: crate::ln::channelmanager::ChannelManager::process_pending_events_async
/// [`ChainMonitor::process_pending_events_async`]: crate::chain::chainmonitor::ChainMonitor::process_pending_events_async
pub trait EventsProvider {
	/// Processes any events generated since the last call using the given event handler.
	///
	/// See the trait-level documentation for requirements.
	fn process_pending_events<H: Deref>(&self, handler: H)
	where
		H::Target: EventHandler;
}

/// An error type that may be returned to LDK in order to safely abort event handling if it can't
/// currently succeed (e.g., due to a persistence failure).
///
/// Depending on the type, LDK may ensure the event is persisted and will eventually be replayed.
/// Please refer to the documentation of each [`Event`] variant for more details.
#[derive(Clone, Copy, Debug)]
pub struct ReplayEvent();

/// A trait implemented for objects handling events from [`EventsProvider`].
///
/// An async variation also exists for implementations of [`EventsProvider`] that support async
/// event handling. The async event handler should satisfy the generic bounds: `F:
/// core::future::Future<Output = Result<(), ReplayEvent>>, H: Fn(Event) -> F`.
pub trait EventHandler {
	/// Handles the given [`Event`].
	///
	/// See [`EventsProvider`] for details that must be considered when implementing this method.
	fn handle_event(&self, event: Event) -> Result<(), ReplayEvent>;
}

impl<F> EventHandler for F
where
	F: Fn(Event) -> Result<(), ReplayEvent>,
{
	fn handle_event(&self, event: Event) -> Result<(), ReplayEvent> {
		self(event)
	}
}

impl<T: EventHandler> EventHandler for Arc<T> {
	fn handle_event(&self, event: Event) -> Result<(), ReplayEvent> {
		self.deref().handle_event(event)
	}
}

/// The BOLT 12 invoice that was paid, surfaced in [`Event::PaymentSent::bolt12_invoice`].
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub enum PaidBolt12Invoice {
	/// The BOLT 12 invoice specified by the BOLT 12 specification,
	/// allowing the user to perform proof of payment.
	Bolt12Invoice(Bolt12Invoice),
	/// The Static invoice, used in the async payment specification update proposal,
	/// where the user cannot perform proof of payment.
	StaticInvoice(StaticInvoice),
}

impl_writeable_tlv_based_enum!(PaidBolt12Invoice,
	{0, Bolt12Invoice} => (),
	{2, StaticInvoice} => (),
);