config.py

# -*- coding: utf-8 -*-
"""
Python Bitcoin Utils CLI — configuration management.
Handles network selection, fee estimation defaults, and tool preferences.
"""
import json
from pathlib import Path
from dataclasses import dataclass, asdict
from typing import Optional


_BASE_DIR = Path(__file__).resolve().parent
_CONFIG_FILE = _BASE_DIR / "btc_config.json"

NETWORKS = {
    "mainnet": {
        "name": "Bitcoin Mainnet",
        "prefix_p2pkh": 0x00,
        "prefix_p2sh": 0x05,
        "bech32_hrp": "bc",
        "wif_prefix": 0x80,
        "explorer": "https://blockstream.info",
    },
    "testnet": {
        "name": "Bitcoin Testnet3",
        "prefix_p2pkh": 0x6F,
        "prefix_p2sh": 0xC4,
        "bech32_hrp": "tb",
        "wif_prefix": 0xEF,
        "explorer": "https://blockstream.info/testnet",
    },
    "signet": {
        "name": "Bitcoin Signet",
        "prefix_p2pkh": 0x6F,
        "prefix_p2sh": 0xC4,
        "bech32_hrp": "tb",
        "wif_prefix": 0xEF,
        "explorer": "https://mutinynet.com",
    },
}

DEFAULT_NETWORK = "testnet"
DEFAULT_FEE_RATE = 10
DEFAULT_DUST_LIMIT = 546
DEFAULT_RBF = True


@dataclass
class BtcConfig:
    network: str = DEFAULT_NETWORK
    fee_rate_sat_vb: int = DEFAULT_FEE_RATE
    dust_limit_sat: int = DEFAULT_DUST_LIMIT
    enable_rbf: bool = DEFAULT_RBF
    address_type: str = "bech32"
    explorer_url: str = NETWORKS[DEFAULT_NETWORK]["explorer"]
    log_level: str = "INFO"
    auto_broadcast: bool = False
    rpc_host: Optional[str] = None
    rpc_port: Optional[int] = None
    rpc_user: Optional[str] = None

    @property
    def network_params(self) -> dict:
        return NETWORKS.get(self.network, NETWORKS["testnet"])

    def validate(self) -> list[str]:
        errors = []
        if self.network not in NETWORKS:
            errors.append(f"Unknown network: {self.network}")
        if self.fee_rate_sat_vb < 1:
            errors.append("Fee rate must be >= 1 sat/vB")
        if self.dust_limit_sat < 0:
            errors.append("Dust limit cannot be negative")
        if self.address_type not in ("legacy", "p2sh-segwit", "bech32", "bech32m"):
            errors.append(f"Unknown address type: {self.address_type}")
        return errors


def load_config() -> BtcConfig:
    """Load configuration from disk or return defaults."""
    if not _CONFIG_FILE.exists():
        cfg = BtcConfig()
        save_config(cfg)
        return cfg

    with open(_CONFIG_FILE, "r", encoding="utf-8") as fp:
        raw = json.load(fp)

    cfg = BtcConfig()
    for k, v in raw.items():
        if hasattr(cfg, k):
            setattr(cfg, k, v)
    return cfg


def save_config(cfg: BtcConfig) -> None:
    """Persist configuration to disk."""
    with open(_CONFIG_FILE, "w", encoding="utf-8") as fp:
        json.dump(asdict(cfg), fp, indent=2, ensure_ascii=False)


def reset_config() -> BtcConfig:
    """Reset to defaults."""
    cfg = BtcConfig()
    save_config(cfg)
    return cfg


def switch_network(network: str) -> Optional[str]:
    """Switch active network. Returns error string or None."""
    if network not in NETWORKS:
        return f"Unknown network '{network}'. Available: {', '.join(NETWORKS.keys())}"
    cfg = load_config()
    cfg.network = network
    cfg.explorer_url = NETWORKS[network]["explorer"]
    save_config(cfg)
    return None