theseus/bundled-addons/bchwallet/lib/chain-bch.js

// BCH chain adapter — wraps the existing keys.js / wallet.js / tx.js /
// electrum.js / cashaddr.js code with the common adapter shape that the
// multi-wallet manager talks to. Every BCH wallet is one BIP32 account
// derived from its own 32-byte root (from api.vault.derive).
//
// Deps are handed in so index.js loads @noble/* once and shares them across
// every wallet, rather than each adapter dynamic-importing on its own.

const BCH_NETWORKS = {
  mainnet: {
    id: "mainnet",
    label: "Mainnet",
    prefix: "bitcoincash",
    defaultAccountPath: "m/44'/145'/0'",
    explorerTx: "https://blockchair.com/bitcoin-cash/transaction/",
    explorerAddr: "https://blockchair.com/bitcoin-cash/address/",
    defaultServers: [
      "wss://bch.imaginary.cash:50004",
      "wss://cashnode.bch.ninja:50004",
      "wss://electroncash.dk:50004",
      "wss://fulcrum.jettscythe.xyz:50004",
    ],
    faucet: null,
  },
  chipnet: {
    id: "chipnet",
    label: "Chipnet testnet",
    prefix: "bchtest",
    // BIP44 testnet coin type is 1 across every chain; the account is still 0.
    defaultAccountPath: "m/44'/1'/0'",
    explorerTx: "https://chipnet.imaginary.cash/tx/",
    explorerAddr: "https://chipnet.imaginary.cash/address/",
    defaultServers: [
      "wss://chipnet.imaginary.cash:50004",
      "wss://chipnet.bch.ninja:50004",
    ],
    faucet: "https://tbch.googol.cash/",
  },
};

module.exports = function makeBchAdapter({
  HDKey, secp256k1, sha256, ripemd160, cashaddr,
  keysLib, tx, electrum, WebSocket,
}) {

  // storage is the FULL api.storage. keyPrefix scopes every read/write under
  // "wallets/<walletId>/…" so multiple BCH wallets don't stomp each other.
  function scopedStorage(storage, keyPrefix) {
    const k = (key) => keyPrefix + key;
    return {
      get: (key, fallback = null) => storage.get(k(key), fallback),
      set: (key, value) => storage.set(k(key), value),
    };
  }

  class BchWallet {
    constructor(root32, {
      walletId, storage, log = () => {}, onChange = () => {}, servers,
      network = "mainnet", accountPath,
    } = {}) {
      if (!walletId) throw new Error("chain-bch: walletId required");
      const net = BCH_NETWORKS[network];
      if (!net) throw new Error(`chain-bch: unknown network ${network}`);
      this.walletId = walletId;
      this.chain = "bch";
      this.network = net.id;
      this._net = net;
      this.log = log;
      this.onChange = onChange;
      this.storage = scopedStorage(storage, `wallets/${walletId}/`);
      // Servers: caller-provided override → user-set custom list (handled by
      // index.js already, this is a fallback path) → the network's built-in
      // defaults so a wallet always has somewhere to connect.
      this._servers = Array.isArray(servers) && servers.length ? servers : net.defaultServers.slice();
      const wantPath = accountPath || net.defaultAccountPath;
      this._accountPath = /^m(\/\d+'?)+$/.test(wantPath) ? wantPath : net.defaultAccountPath;
      this._client = new electrum.Client(this._servers);
      this._client.onServer = () => this._emit();
      this._keys = new keysLib.WalletKeys(root32, this._accountPath, net.prefix);
      this._root = new Uint8Array(root32);
      const walletFactory = require("./wallet.js");
      this._wallet = walletFactory({
        client: this._client, keys: this._keys, tx, cashaddr, sha256,
        storage: this.storage,
        log: (...a) => this.log(...a),
        onChange: () => this._emit(),
      });
    }

    setServers(list) {
      this._servers = Array.isArray(list) && list.length ? list : this._net.defaultServers.slice();
      this._client.setServers(this._servers);
    }

    _emit() { try { this.onChange(); } catch {} }

    snapshot() {
      const w = this._wallet.snapshot();
      return {
        chain: "bch",
        network: this._net.id,
        ticker: "BCH",
        decimals: 8,
        address: w.address,
        addressIndex: w.addressIndex,
        addressPath: w.addressPath,
        balance: w.balance,
        height: w.height,
        history: w.history,
        scanning: w.scanning,
        error: w.error,
        server: this._client.url || null,
        servers: this._servers,
        accountPath: this._accountPath,
        xpub: this._keys.xpub,
        explorerTx: this._net.explorerTx,
        explorerAddr: this._net.explorerAddr,
        faucet: this._net.faucet,
      };
    }

    async refresh(full) { return this._wallet.refresh(!!full); }
    nextAddress() { return this._wallet.nextUnusedAddress(); }
    current() { return this._wallet.current(); }
    plan(spec) {
      const targets = Array.isArray(spec.outputs) && spec.outputs.length
        ? spec.outputs.map((o) => ({ to: o.to, value: o.amount ?? o.value }))
        : [{ to: spec.to, value: spec.amount ?? spec.value }];
      return this._wallet.plan({ targets, feeRate: spec.feeRate, sendMax: !!spec.sendMax });
    }
    async signAndBroadcast(plan) { return this._wallet.signAndBroadcast(plan); }
    // 65-byte BIP-137 recoverable signature — the format Electron Cash and
    // most BCH tooling verify against.
    signMessage(message) {
      const enc = new TextEncoder();
      const varstr = (s) => { const b = enc.encode(s); if (b.length >= 0xfd) throw new Error("too long"); return Uint8Array.from([b.length, ...b]); };
      const MAGIC = "Bitcoin Signed Message:\n";
      const payload = Uint8Array.from([...varstr(MAGIC), ...varstr(String(message))]);
      const digest = sha256(sha256(payload));
      const entry = this.current();
      const sig = this._keys.signRecoverable(entry, digest);
      return { address: entry.address, signature: Buffer.from(sig).toString("base64") };
    }
    recovery() {
      return { accountPath: this._accountPath, xpub: this._keys.xpub, xprv: this._keys.xprv };
    }
    dispose() {
      try { this._wallet.dispose(); } catch {}
      try { this._keys.wipe(); } catch {}
      try { this._client.disconnect(); } catch {}
      if (this._root) this._root.fill(0);
    }
  }

  return { BchWallet, BCH_NETWORKS };
};