// Imported BCH wallet — single-address, key material lives in Theseus's
// wallet-imports.enc (design §3.2). This adapter mirrors chain-bch.js's
// public shape (snapshot, refresh, plan, signAndBroadcast, signMessage,
// dispose) but does NOT go through vault.derive + HKDF: derivation is
// direct from the seed+path or WIF that the user imported.
//
// 0.6.36+: spend path enabled. plan() builds a P2PKH tx off the wallet's
// single scripthash UTXO set; signAndBroadcast() pulls the signer material
// from api.vault.imports.signer(importId), decodes the WIF or derives the
// mnemonic/path into a 32-byte priv key, and signs every input in RAM.
// The private key never lands in adapter state — signAndBroadcast fetches
// it fresh per broadcast and drops it before returning.

module.exports = function makeImportedBchAdapter({
  sha256, ripemd160, cashaddr, electrum, WebSocket, tx,
  HDKey, secp256k1, base58check, vaultImports,
}) {

  const toHex = (b) => Array.from(b, (x) => x.toString(16).padStart(2, "0")).join("");
  const p2pkhScript = (h160) => Uint8Array.from([0x76, 0xa9, 0x14, ...h160, 0x88, 0xac]);
  const scripthashOf = (script) => toHex(sha256(script).slice().reverse());
  const hash160 = (b) => ripemd160(sha256(b));

  const IMPORTED_BCH_NETWORKS = {
    mainnet: {
      id: "mainnet", label: "Mainnet", prefix: "bitcoincash", wifVersion: 0x80,
      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",
      ],
    },
    chipnet: {
      id: "chipnet", label: "Chipnet testnet", prefix: "bchtest", wifVersion: 0xef,
      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/",
    },
  };

  function h160OfCashaddr(addr) {
    const clean = String(addr || "").replace(/^bitcoincash:|^bchtest:/, "");
    const { type, hash } = cashaddr.decode(addr.includes(":") ? addr : "bitcoincash:" + clean);
    if (type !== 0) throw new Error(`imported wallet must be P2PKH (got type ${type})`);
    return hash;
  }

  // Decode a WIF-encoded private key. Accepts both mainnet (0x80) and
  // testnet (0xef) version bytes and both compressed and uncompressed
  // forms; returns { priv (32 bytes), compressed (bool) }.
  function decodeWif(wif, versionByte) {
    const bytes = base58check.decodeCheck(String(wif).trim());
    if (!(bytes[0] === versionByte || bytes[0] === 0x80 || bytes[0] === 0xef)) {
      throw new Error(`unexpected WIF version 0x${bytes[0].toString(16)}`);
    }
    const compressed = bytes.length === 34 && bytes[33] === 0x01;
    const priv = bytes.slice(1, 33);
    if (priv.length !== 32) throw new Error("WIF payload is not 32 bytes");
    return { priv, compressed };
  }

  // Derive a P2PKH signer (32-byte priv + 33-byte compressed pubkey) from
  // whatever vault.imports.signer returned. Two shapes today:
  //   { kind: "seed", seed: hex, path: "m/…" } — BIP32 derivation
  //   { kind: "wif",  wif:  base58check }      — direct decode
  // Anything else (or a missing signer) throws with a clear message so
  // the panel can surface it rather than the broadcast returning garbage.
  function signerToKey(signerBlob, net) {
    if (!signerBlob) throw new Error("no signer material for this wallet");
    if (signerBlob.kind === "seed") {
      const seed = signerBlob.seed;
      if (!/^[0-9a-f]+$/i.test(seed)) throw new Error("seed material must be hex");
      const seedBytes = Uint8Array.from(seed.match(/../g).map((x) => parseInt(x, 16)));
      const node = HDKey.fromMasterSeed(seedBytes).derive(signerBlob.path || "m");
      return { priv: node.privateKey, pub: node.publicKey };
    }
    if (signerBlob.kind === "wif") {
      const { priv } = decodeWif(signerBlob.wif, net.wifVersion);
      const pub = secp256k1.getPublicKey(priv, true);
      return { priv, pub };
    }
    throw new Error(`unknown signer kind: ${signerBlob.kind}`);
  }

  class ImportedBchWallet {
    constructor({
      walletId, storage, log = () => {}, onChange = () => {},
      network = "mainnet", cashaddr: address, servers, importId,
    } = {}) {
      const net = IMPORTED_BCH_NETWORKS[network];
      if (!net) throw new Error(`chain-bch-imported: unknown network ${network}`);
      if (!address) throw new Error("chain-bch-imported: cashaddr required");
      this.walletId = walletId;
      // importId is the vault-side id used to fetch the signer at
      // sign-time. Optional here so a mount without spend capability
      // still works (read-only surface unaffected).
      this._importId = importId || null;
      this.chain = "bch";
      this.network = net.id;
      this._net = net;
      this.log = log;
      this.onChange = onChange;
      this._address = address;
      this._h160 = h160OfCashaddr(address);
      this._script = p2pkhScript(this._h160);
      this._scripthash = scripthashOf(this._script);
      this._scriptHex = toHex(this._script);
      this._servers = Array.isArray(servers) && servers.length ? servers : net.defaultServers.slice();
      this._client = new electrum.Client(this._servers);
      this._client.onServer = () => this._emit();
      this._state = {
        balance: { confirmed: 0, unconfirmed: 0 },
        history: [],
        utxos: [],
        height: 0,
        scanning: false,
        error: null,
      };
    }

    setServers(list) {
      this._servers = Array.isArray(list) && list.length ? list : this._net.defaultServers.slice();
      this._client.setServers(this._servers);
    }
    schedulePoll(ms) {
      clearTimeout(this._pollTimer);
      this._pollTimer = setTimeout(() => { this.refresh(false).catch(() => {}); this.schedulePoll(ms); }, ms);
    }

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

    snapshot() {
      return {
        chain: "bch",
        network: this._net.id,
        ticker: "BCH",
        decimals: 8,
        address: this._address,
        addressIndex: 0,
        addressPath: null,
        balance: this._state.balance,
        height: this._state.height,
        history: this._state.history,
        scanning: this._state.scanning,
        error: this._state.error,
        server: this._client.url || null,
        servers: this._servers,
        imported: true,
        // 0.6.36+: imported wallets can spend when the vault signer is
        // reachable (i.e. Theseus is unlocked). canSpend reflects that so
        // the panel can enable the Send tab without probing.
        canSpend: !!this._importId,
        explorerTx: this._net.explorerTx,
        explorerAddr: this._net.explorerAddr,
        faucet: this._net.faucet,
      };
    }

    async refresh(full) {
      this._state.scanning = true; this._emit();
      try {
        const bal = await this._client.call("blockchain.scripthash.get_balance", [this._scripthash]);
        this._state.balance = { confirmed: Number(bal?.confirmed || 0), unconfirmed: Number(bal?.unconfirmed || 0) };
        // Always pull UTXOs so spend / send-max work off fresh state.
        const utxos = await this._client.call("blockchain.scripthash.listunspent", [this._scripthash]);
        this._state.utxos = (Array.isArray(utxos) ? utxos : []).map((u) => ({
          txid: u.tx_hash, vout: u.tx_pos, value: Number(u.value), height: Number(u.height || 0),
        }));
        if (full) {
          const hist = await this._client.call("blockchain.scripthash.get_history", [this._scripthash]);
          this._state.history = (hist || []).slice(-50).map((h) => ({
            txid: h.tx_hash, time: 0, delta: 0, confirmations: h.height > 0 ? 1 : 0,
          }));
        }
        this._state.error = null;
      } catch (e) {
        this._state.error = e?.message || String(e);
      } finally {
        this._state.scanning = false;
        this._emit();
      }
    }

    nextAddress() { return { address: this._address, index: 0 }; }
    current() {
      return {
        address: this._address, index: 0, branch: 0, path: null,
        h160: this._h160, script: this._script, scripthash: this._scripthash, scriptHex: this._scriptHex,
      };
    }

    // 0.6.36 spend path. Builds an unsigned P2PKH plan against the wallet's
    // own UTXO set. Signing happens in signAndBroadcast, which fetches the
    // key material from Theseus's vault at broadcast time — nothing key-
    // bearing lives in the plan itself, so a plan can round-trip through
    // the approval overlay without leaking secrets.
    plan(spec) {
      if (!this._state.utxos.length) throw new Error("wallet has no unspent outputs to spend from");
      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 }];
      const outs = targets.map((t) => {
        const a = cashaddr.parseAny(t.to, sha256, this._net.prefix);
        const script = a.type === 0
          ? Uint8Array.from([0x76, 0xa9, 0x14, ...a.hash, 0x88, 0xac])
          : Uint8Array.from([0xa9, 0x14, ...a.hash, 0x87]);
        return { value: Math.round(Number(t.value) || 0), script, to: a.cashaddr };
      });
      if (spec?.memo) outs.push({ value: 0, script: tx.memoScript(String(spec.memo)), data: true, memo: String(spec.memo) });
      const rate = Math.min(10, Math.max(1, Number(spec?.feeRate) || 1));
      // Imported wallets have exactly one address, so change goes back to
      // itself — no need to derive a fresh change entry from an HD tree.
      const changeScript = this._script;
      const spendable = this._state.utxos.slice().sort((a, b) => (b.height > 0) - (a.height > 0));
      const sel = tx.select(spendable, outs, rate, changeScript, { sendMax: !!spec?.sendMax });
      const nonData = sel.outputs.filter((o) => !o.data);
      const total = sel.outputs.reduce((a, o) => a + o.value, 0);
      return {
        ...sel,
        feeRate: rate,
        recipients: nonData
          .filter((_, i) => outs[i] && !outs[i].data)
          .map((o, i) => ({ to: outs[i].to, value: o.value })),
        memo: spec?.memo || null,
        total,
      };
    }

    async signAndBroadcast(plan) {
      if (!this._importId) throw new Error("this wallet has no signer registered");
      if (!vaultImports || typeof vaultImports.signer !== "function") throw new Error("vault.imports.signer unavailable");
      const signerBlob = await vaultImports.signer(this._importId);
      let key;
      try {
        key = signerToKey(signerBlob, this._net);
        // Belt-and-braces: the signer must match the wallet's own address.
        // Catches vault-side corruption and any accidental cross-mount.
        const derivedH160 = hash160(key.pub);
        const same = derivedH160.length === this._h160.length && derivedH160.every((b, i) => b === this._h160[i]);
        if (!same) throw new Error("signer material does not match this wallet's address");
        const inputs = plan.inputs.map((u) => ({ ...u, script: this._script }));
        const t = { inputs, outputs: plan.outputs };
        const signed = tx.sign(t, (inp, _i, digest) => ({
          sig: secp256k1.sign(digest, key.priv, { prehash: false, lowS: true, format: "der" }),
          publicKey: key.pub,
        }));
        const txid = await this._client.call("blockchain.transaction.broadcast", [signed.hex]);
        if (typeof txid !== "string" || txid.length !== 64) throw new Error("broadcast rejected: " + JSON.stringify(txid));
        this.log("broadcast", txid);
        setTimeout(() => this.refresh(false).catch(() => {}), 1500);
        return { txid, hex: signed.hex, fee: plan.fee };
      } finally {
        // Wipe the private material before returning. Not perfect (JS can
        // still relocate the underlying buffer during GC) but it minimises
        // the window in which the raw key sits in this frame.
        if (key && key.priv && key.priv.fill) { try { key.priv.fill(0); } catch {} }
      }
    }

    // BIP-137 message signing from the imported key. Same MAGIC / double-
    // sha256 payload as chain-bch.js so the resulting sig verifies through
    // Electron Cash and every other BCH tool.
    async signMessage(message) {
      if (!this._importId) throw new Error("this wallet has no signer registered");
      if (!vaultImports || typeof vaultImports.signer !== "function") throw new Error("vault.imports.signer unavailable");
      const signerBlob = await vaultImports.signer(this._importId);
      let key;
      try {
        key = signerToKey(signerBlob, this._net);
        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 sig = secp256k1.sign(digest, key.priv, { prehash: false, lowS: true, format: "recovered" });
        const out = new Uint8Array(65);
        out[0] = 27 + sig[0] + 4;
        out.set(sig.subarray(1), 1);
        return { address: this._address, signature: Buffer.from(out).toString("base64") };
      } finally {
        if (key && key.priv && key.priv.fill) { try { key.priv.fill(0); } catch {} }
      }
    }

    recovery() { return { accountPath: null, xpub: null, xprv: null, note: "Recovery lives in the source of the import (Deviant keystore or wherever you got the seed/WIF from)." }; }

    dispose() { clearTimeout(this._pollTimer); try { this._client.disconnect(); } catch {} }
  }

  return { ImportedBchWallet, IMPORTED_BCH_NETWORKS };
};