// Tron chain adapter (mainnet + Nile testnet). One address per wallet, in the
// TronLink style: seed for this wallet → BIP32 → m/44'/195'/0'/0/0 → secp256k1
// private key → uncompressed pubkey (drop 0x04) → keccak256 last 20 bytes →
// prepend 0x41 → base58check → "T..." address.
//
// Balance and history come from TronGrid (read; no key required). Send is
// build-locally-signed-locally-broadcast-remotely:
//   POST /wallet/createtransaction {owner_address, to_address, amount, visible:true}
//     → { raw_data, raw_data_hex, txID, ... }
//   sig = secp256k1.sign(sha256(raw_data_hex), privateKey, {format:"recovered"})
//     → 65 bytes [r||s||recid]
//   POST /wallet/broadcasttransaction {raw_data, raw_data_hex, txID, signature:[hexSig]}
//     → { result: true/false, txid/message }
//
// Nile and mainnet share the address format (both prefix 0x41). The RPC host
// differs. Coin type 195 is used for both — the derivation-path *string* is
// identical; the difference between mainnet and Nile is which sub-wallet the
// user picked, which vault-derive purpose seeded it, and which RPC we hit.
// Two addresses; a mainnet wallet's key cannot accidentally sign for Nile
// (different key material entirely; the check is enforced at the seed layer).

const NETWORKS = {
  mainnet: {
    id: "mainnet",
    label: "Tron",
    ticker: "TRX",
    rpcBase: "https://api.trongrid.io",
    explorerTx: "https://tronscan.org/#/transaction/",
    explorerAddr: "https://tronscan.org/#/address/",
    faucet: null,
  },
  nile: {
    id: "nile",
    label: "Tron Nile testnet",
    ticker: "TRX",
    rpcBase: "https://nile.trongrid.io",
    explorerTx: "https://nile.tronscan.org/#/transaction/",
    explorerAddr: "https://nile.tronscan.org/#/address/",
    faucet: "https://nileex.io/join/getJoinPage",
  },
};

module.exports = function makeTronAdapter({ HDKey, secp256k1, sha256, keccak_256, base58check }) {
  if (!HDKey || !secp256k1 || !sha256 || !keccak_256 || !base58check) {
    throw new Error("chain-tron: missing dep");
  }
  const bytesToHex = (b) => Array.from(b, (x) => x.toString(16).padStart(2, "0")).join("");
  const hexToBytes = (h) => {
    const s = String(h).replace(/^0x/i, "");
    if (s.length % 2) throw new Error("hex: odd length");
    const out = new Uint8Array(s.length / 2);
    for (let i = 0; i < out.length; i++) out[i] = parseInt(s.slice(i * 2, i * 2 + 2), 16);
    return out;
  };

  // Derive the raw key material for a single Tron account.
  //   root32:  32-byte HKDF child from api.vault.derive.
  //   returns: { privateKey (Uint8Array 32), publicKey (Uint8Array 65 uncompressed),
  //             addressBytes (Uint8Array 21, prefix 0x41 || h20), address (base58) }
  function deriveAccount(root32) {
    const master = HDKey.fromMasterSeed(root32);
    // Tron follows Ethereum-style non-hardened branch/index: m/44'/195'/0'/0/0.
    const node = master.derive("m/44'/195'/0'/0/0");
    const priv = node.privateKey;
    // Uncompressed pub is 65 bytes with a 0x04 prefix; drop it to feed keccak256.
    const pubUncompressed = secp256k1.getPublicKey(priv, false);
    const inner = pubUncompressed.slice(1);   // 64 bytes
    const kh = keccak_256(inner);              // 32 bytes
    const h20 = kh.slice(kh.length - 20);
    const addrBytes = new Uint8Array(21);
    addrBytes[0] = 0x41;
    addrBytes.set(h20, 1);
    const address = base58check.encodeCheck(addrBytes);
    return { privateKey: priv, publicKey: pubUncompressed, addressBytes: addrBytes, address, node };
  }

  // "T..." → 21-byte payload (0x41 || h20). Throws on bad checksum / prefix.
  function decodeAddress(str) {
    const payload = base58check.decodeCheck(String(str).trim());
    if (payload.length !== 21) throw new Error("bad address length");
    if (payload[0] !== 0x41) throw new Error("bad address prefix (want 0x41 / T…)");
    return payload;
  }
  function hexToAddress(hex) {
    const b = hexToBytes(hex);
    if (b.length !== 21 || b[0] !== 0x41) throw new Error("bad address hex");
    return base58check.encodeCheck(b);
  }

  function makeClient(networkId) {
    const net = NETWORKS[networkId];
    if (!net) throw new Error(`unknown Tron network ${networkId}`);
    async function rpc(pathPart, body) {
      const url = net.rpcBase + pathPart;
      let r;
      try { r = await fetch(url, { method: "POST", headers: { "content-type": "application/json" }, body: JSON.stringify(body || {}) }); }
      catch (e) { throw new Error(`network: ${e?.message || e}`); }
      if (!r.ok) throw new Error(`${pathPart}: HTTP ${r.status}`);
      return r.json();
    }
    async function get(pathPart) {
      const url = net.rpcBase + pathPart;
      const r = await fetch(url);
      if (!r.ok) throw new Error(`${pathPart}: HTTP ${r.status}`);
      return r.json();
    }
    return { net, rpc, get };
  }

  class TronWallet {
    constructor(root32, networkId, { storage, log = () => {}, onChange = () => {} } = {}) {
      this.storage = storage;
      this.log = log;
      this.onChange = onChange;
      this.client = makeClient(networkId);
      this.net = this.client.net;
      const acc = deriveAccount(root32);
      // Root is stored so future revs can rotate accounts; the derived priv
      // is what actually signs. Both wiped in dispose().
      this._root = new Uint8Array(root32);
      this._priv = acc.privateKey;
      this.publicKey = acc.publicKey;
      this.addressBytes = acc.addressBytes;
      this.address = acc.address;
      this.state = {
        balance: { confirmed: 0, unconfirmed: 0 },
        history: [],
        height: 0,
        scanning: false,
        error: null,
        server: this.net.rpcBase,
      };
      this._pollTimer = null;
    }

    // Public snapshot (no key material).
    snapshot() {
      return {
        chain: "trx",
        network: this.net.id,
        ticker: this.net.ticker,
        address: this.address,
        addressIndex: 0,
        addressPath: "m/44'/195'/0'/0/0",
        balance: this.state.balance,
        height: this.state.height,
        history: this.state.history,
        scanning: this.state.scanning,
        error: this.state.error,
        server: this.state.server,
        explorerTx: this.net.explorerTx,
        explorerAddr: this.net.explorerAddr,
        faucet: this.net.faucet,
        decimals: 6,
      };
    }

    async refresh(_full = false) {
      if (this.state.scanning) return;
      this.state.scanning = true; this.state.error = null; this.onChange();
      try {
        const [acc, txs] = await Promise.all([this._fetchAccount(), this._fetchHistory()]);
        // TronGrid returns balance in "sun" (1 TRX = 1_000_000 sun).
        const sun = Number(acc?.balance || 0);
        this.state.balance = { confirmed: sun, unconfirmed: 0 };
        this.state.history = txs;
        // Block height comes from any recent tx or a getnowblock call.
        try {
          const nb = await this.client.rpc("/wallet/getnowblock", {});
          this.state.height = Number(nb?.block_header?.raw_data?.number || 0);
        } catch {}
      } catch (e) {
        this.state.error = e?.message || String(e);
        this.log("refresh failed:", this.state.error);
      } finally {
        this.state.scanning = false;
        this.onChange();
      }
    }

    schedulePoll(ms = 20_000) {
      clearTimeout(this._pollTimer);
      this._pollTimer = setTimeout(() => this.refresh(false).finally(() => this.schedulePoll(ms)), ms);
    }

    async _fetchAccount() {
      const body = { address: this.address, visible: true };
      // /wallet/getaccount returns {} for never-funded addresses.
      return this.client.rpc("/wallet/getaccount", body);
    }

    async _fetchHistory() {
      const url = `/v1/accounts/${encodeURIComponent(this.address)}/transactions?limit=25`;
      let raw;
      try { raw = await this.client.get(url); } catch (e) { this.log("history failed:", e?.message || e); return []; }
      const list = Array.isArray(raw?.data) ? raw.data : [];
      const now = Math.floor(Date.now() / 1000);
      return list.map((t) => this._describeTx(t, now)).filter(Boolean);
    }

    _describeTx(t, nowSec) {
      const contract = t?.raw_data?.contract?.[0];
      const type = contract?.type;
      const value = contract?.parameter?.value || {};
      const txID = t.txID || t.txid;
      const time = Math.floor((t.block_timestamp || t.raw_data?.timestamp || 0) / 1000);
      const conf = t.ret && Array.isArray(t.ret) ? (t.ret[0]?.contractRet === "SUCCESS" ? 1 : -1) : 0;
      if (type === "TransferContract") {
        // owner_address / to_address come as hex here (prefixed 41), regardless
        // of visible:true (that flag only affects some endpoints).
        let ownerB58 = "", toB58 = "";
        try { ownerB58 = value.owner_address ? hexToAddress(value.owner_address) : ""; } catch {}
        try { toB58 = value.to_address ? hexToAddress(value.to_address) : ""; } catch {}
        const amount = Number(value.amount || 0);
        const inc = toB58 === this.address;
        return {
          txid: txID,
          delta: inc ? amount : -amount,
          to: inc ? null : toB58,
          from: inc ? ownerB58 : null,
          fee: t.net_fee || t.energy_fee || null,
          time: time || 0,
          confirmations: conf > 0 ? 1 : (conf < 0 ? 0 : 0),
          status: conf > 0 ? "confirmed" : (conf < 0 ? "failed" : "pending"),
          kind: "transfer",
        };
      }
      // Non-transfer contracts (delegation, votes, TRC20) — surface as a
      // neutral entry so users see something happened without exaggerating.
      return {
        txid: txID,
        delta: 0,
        to: null, from: null, fee: null,
        time: time || 0,
        confirmations: conf > 0 ? 1 : 0,
        status: conf > 0 ? "confirmed" : "other",
        kind: type || "contract",
      };
    }

    // Preview a send: no side effects, no signature. Returns the fields the
    // panel needs plus the raw createtransaction result cached under _draft
    // so signAndBroadcast doesn't re-fetch.
    async plan({ to, amount, sendMax }) {
      if (!to) throw new Error("recipient required");
      const dest = decodeAddress(to);
      const balance = this.state.balance.confirmed;
      // Tron doesn't have a fee-market for plain TRX transfers between accounts
      // that carry enough bandwidth. For untouched addresses the network
      // consumes a fixed 100_000 sun (0.1 TRX) burn from the sender if no
      // free bandwidth is available. We show that as an upper-bound estimate.
      const FEE_EST = 100_000;
      let value;
      if (sendMax) {
        value = Math.max(0, balance - FEE_EST);
      } else {
        value = Math.round(Number(amount) || 0);
      }
      if (!(value > 0)) throw new Error("amount must be > 0 sun");
      if (value + FEE_EST > balance) throw new Error("insufficient funds");
      const body = { owner_address: this.address, to_address: base58check.encodeCheck(dest), amount: value, visible: true };
      const draft = await this.client.rpc("/wallet/createtransaction", body);
      if (draft?.Error || !draft?.raw_data_hex) {
        throw new Error("createtransaction: " + (draft?.Error || "empty response"));
      }
      const plan = {
        recipients: [{ to: base58check.encodeCheck(dest), value }],
        fee: FEE_EST,
        feeRate: 1,
        total: value + FEE_EST,
        inputs: [],
        _draft: draft,
      };
      return plan;
    }

    // Sign the raw_data_hex bytes with the wallet key and POST the signed tx.
    async signAndBroadcast(plan) {
      const draft = plan && plan._draft;
      if (!draft || !draft.raw_data_hex) throw new Error("bad plan");
      const rawBytes = hexToBytes(draft.raw_data_hex);
      const digest = sha256(rawBytes);
      const sig = secp256k1.sign(digest, this._priv, { prehash: false, lowS: false, format: "recovered" });
      // Recovered format from noble is 65 bytes: [recid || r(32) || s(32)]. Tron
      // wants [r(32) || s(32) || recid]. Reorder in place.
      const trxSig = new Uint8Array(65);
      trxSig.set(sig.subarray(1), 0);
      trxSig[64] = sig[0];
      const body = {
        raw_data: draft.raw_data,
        raw_data_hex: draft.raw_data_hex,
        txID: draft.txID,
        visible: true,
        signature: [bytesToHex(trxSig)],
      };
      const r = await this.client.rpc("/wallet/broadcasttransaction", body);
      if (r?.result !== true) {
        const msg = r?.message ? Buffer.from(r.message, "hex").toString("utf8") : (r?.code || "broadcast rejected");
        throw new Error("broadcast: " + msg);
      }
      // Refresh soon so history/balance catch up.
      setTimeout(() => this.refresh(false), 2500);
      return { txid: draft.txID };
    }

    // BIP137-style signing isn't standard on Tron; dapps use signMessageV2
    // (tronWeb.trx.signMessageV2), which is a raw ECDSA over sha256 of the
    // message bytes with a Tron prefix "\x19TRON Signed Message:\n32". Kept
    // simple here: signMessageV2 always asks the user.
    signMessageV2(message) {
      const enc = new TextEncoder();
      const bodyBytes = enc.encode(String(message));
      const prefix = enc.encode("\x19TRON Signed Message:\n" + bodyBytes.length);
      const buf = new Uint8Array(prefix.length + bodyBytes.length);
      buf.set(prefix, 0); buf.set(bodyBytes, prefix.length);
      const digest = keccak_256(buf);
      const sig = secp256k1.sign(digest, this._priv, { prehash: false, lowS: false, format: "recovered" });
      const out = new Uint8Array(65);
      out.set(sig.subarray(1), 0);
      out[64] = sig[0] + 27;   // Ethereum-style v = 27 + recid
      return { address: this.address, signature: "0x" + bytesToHex(out) };
    }

    // Sign an arbitrary raw_data_hex the dapp built with its own tronWeb.
    // The caller must have already presented an approval overlay.
    signRawData(rawDataHex) {
      const rawBytes = hexToBytes(rawDataHex);
      const digest = sha256(rawBytes);
      const sig = secp256k1.sign(digest, this._priv, { prehash: false, lowS: false, format: "recovered" });
      const trxSig = new Uint8Array(65);
      trxSig.set(sig.subarray(1), 0);
      trxSig[64] = sig[0];
      return bytesToHex(trxSig);
    }

    async broadcastSignedTx(signedTx) {
      const r = await this.client.rpc("/wallet/broadcasttransaction", signedTx);
      if (r?.result !== true) {
        const msg = r?.message ? Buffer.from(r.message, "hex").toString("utf8") : (r?.code || "broadcast rejected");
        throw new Error("broadcast: " + msg);
      }
      return { txid: signedTx.txID };
    }

    dispose() {
      clearTimeout(this._pollTimer);
      try { this._priv && this._priv.fill(0); } catch {}
      try { this._root && this._root.fill(0); } catch {}
    }
  }

  return { TronWallet, deriveAccount, decodeAddress, hexToAddress, NETWORKS };
};