// WizardConnect wallet-side bridge for Aegis.
//
// Aegis's BCH runtime acts as a WizardConnect wallet: sites we build (dapps)
// pair via a wiz:// URI, get xpubs for BCH derivation paths, and send us
// sign requests that we route through the existing approval-modal capability.
//
// LGPL boundary: @wizardconnect/{core,wallet} are dynamic-linked via
// api.import(); we do not statically embed them. Their sources live at
// https://github.com/whiterun-labs/wizardconnect (also on npm) and their
// LICENSE / copyright headers are shipped by npm inside the package.
//
// Docs: https://docs.riftenlabs.com/wizardconnect/

const WC_PATH_RECEIVE  = "receive";   // m/44'/145'/0'/0
const WC_PATH_CHANGE   = "change";    // m/44'/145'/0'/1
const WC_PATH_CAULDRON = "defi";      // m/44'/145'/0'/7 (BCH DEX ecosystem)

const WALLET_ICON = "data:image/svg+xml;utf8," + encodeURIComponent(
  `<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 32 32' fill='none'>
    <polygon points='16,2 28,9 28,23 16,30 4,23 4,9' fill='#0a0a0d' stroke='#D6FF3D' stroke-width='1.6' stroke-linejoin='round'/>
    <circle cx='16' cy='16' r='4.5' fill='none' stroke='#D6FF3D' stroke-width='1.4'/>
    <circle cx='16' cy='16' r='1.6' fill='#D6FF3D'/>
  </svg>`
);

module.exports = function makeWc({ HDKey, secp256k1, sha256, hkdf, WalletConnectionManager, wcCore, libauth, log = () => {}, api, approvalRequest }) {

  // ---- WalletAdapter --------------------------------------------------------
  //
  // Bound to one BCH runtime. Uses its 32-byte root to reproduce the account
  // HDKey and to derive per-URI relay identities via HKDF, so reconnecting
  // yields the same Nostr identity (dapp recognises us on reload).
  function makeAdapter({ root32, accountPath, walletId, label }) {
    // Own copy: the caller may wipe its buffer once this returns.
    root32 = new Uint8Array(root32);
    const account = HDKey.fromMasterSeed(root32).derive(accountPath);
    const branches = new Map();
    const branchFor = (childIndex) => {
      let b = branches.get(childIndex);
      if (!b) { b = account.deriveChild(childIndex); branches.set(childIndex, b); }
      return b;
    };
    // WC path enum → BCH child index (identity mapping today; enum members
    // hold the numeric child index directly — see docs/protocol.
    const childOf = (path) => Number(path);

    return {
      walletName: label ? `Aegis · ${label}` : "Aegis",
      walletIcon: WALLET_ICON,

      // Stable identity per pairing URI. HKDF salt binds it to this wallet's
      // root, info binds it to the URI, so:
      //  - reconnecting to the same URI = same Nostr identity
      //  - two different URIs = uncorrelatable identities (privacy)
      getRelayPrivateKey(uri) {
        const salt = new TextEncoder().encode("aegis/wc/relay/v1");
        const info = new TextEncoder().encode(uri);
        // 32 bytes for a Nostr secp256k1 private key.
        return hkdf(sha256, root32, salt, info, 32);
      },

      getPublicKey(path, index) {
        const branch = branchFor(childOf(path));
        const node = branch.deriveChild(Number(index));
        return node.publicKey; // 33 bytes compressed
      },

      getXpub(path) {
        return branchFor(childOf(path)).publicExtendedKey;
      },

      // Sign a transaction the dapp has already assembled. See signTx.js for
      // the heavy lifting (SIGHASH_ALL|FORKID|UTXOS enforcement, libauth
      // preimage + secp256k1 der/lowS signatures).
      // `pairing` is what Aegis itself recorded when this connection was
      // made ({ origin } — the page origin the host verified, or "panel"),
      // never what the dapp says about itself: the dapp's userPrompt and
      // name are free text it controls.
      async signTransaction(request, pairing = null) {
        // Route through approval-modal first — the user always sees what
        // they're signing before any private key touches the request.
        if (!approvalRequest) throw new Error("no approval channel");
        const decision = await approvalRequest({
          kind: "wc-sign",
          walletId, label,
          request,
          pairing,
        });
        if (!decision?.approved) throw new Error("cancelled");
        const { signTx } = require("./wc-sign.js");
        return signTx({
          request,
          account,
          branches: { receive: branchFor(0), change: branchFor(1), defi: branchFor(7) },
          libauth, secp256k1,
        });
      },
    };
  }

  // ---- connection tracker --------------------------------------------------

  // One manager per BCH wallet. We keep them in a per-walletId map so the
  // panel can show "Wallet A connected to 2 dapps, Wallet B to none" etc.
  const managers = new Map();       // walletId -> WalletConnectionManager
  const uris = new Map();           // walletId -> Set<uri> (persisted)
  const origins = new Map();        // walletId -> Map<uri, { origin, at }> (persisted)
  const busy = new Set();           // connection ids with a sign request on screen
  const listeners = new Set();      // () => void — panel resubscribes on state change

  function fireStateChange() { for (const fn of listeners) try { fn(); } catch {} }

  function persist(walletId) {
    const list = [...(uris.get(walletId) || new Set())];
    api.storage.set(`wc/${walletId}/uris`, list);
    const o = origins.get(walletId) || new Map();
    for (const u of [...o.keys()]) if (!list.includes(u)) o.delete(u);
    api.storage.set(`wc/${walletId}/origins`, Object.fromEntries(o));
  }
  function uriOf(mgr, connectionId) {
    const all = typeof mgr.getConnections === "function" ? Object.values(mgr.getConnections() || {}) : [...(mgr.connections?.values?.() || [])];
    return all.find((c) => c.id === connectionId)?.uri || null;
  }

  async function startForWallet({ walletId, label, root32, accountPath }) {
    if (managers.has(walletId)) return managers.get(walletId);
    const adapter = makeAdapter({ root32, accountPath, walletId, label });
    const mgr = new WalletConnectionManager(adapter);
    managers.set(walletId, mgr);

    mgr.on("connectionsChanged", fireStateChange);
    mgr.on("connectionStatusChanged", fireStateChange);
    mgr.on("remoteDisconnect", (connId, reason) => {
      log(`wc[${walletId}] remote disconnect ${connId}: ${reason}`);
      fireStateChange();
    });
    mgr.on("pendingSignRequest", async ({ connectionId, request }) => {
      // One request per connection on screen at a time: a paired dapp can
      // send over the relay whenever it likes, with no tab open, and must not
      // be able to stack overlays.
      if (busy.has(connectionId)) {
        try { await mgr.sendSignError(connectionId, request?.sequence, "another request from this dapp is waiting for the user"); } catch {}
        return;
      }
      busy.add(connectionId);
      try {
        const uri = uriOf(mgr, connectionId);
        const pairing = (uri && origins.get(walletId)?.get(uri)) || null;
        const { signedTransaction } = await adapter.signTransaction(request, pairing);
        await mgr.sendSignResponse(connectionId, request.sequence, signedTransaction);
      } catch (e) {
        log(`wc[${walletId}] sign failed:`, e?.message || e);
        try { await mgr.sendSignError(connectionId, request.sequence, cleanErrForDapp(e)); } catch {}
      } finally { busy.delete(connectionId); }
    });

    // Restore persisted pairings.
    uris.set(walletId, new Set(api.storage.get(`wc/${walletId}/uris`, []) || []));
    const savedOrigins = api.storage.get(`wc/${walletId}/origins`, {}) || {};
    origins.set(walletId, new Map(Object.entries(savedOrigins).filter(([, v]) => v && typeof v.origin === "string")));
    for (const uri of uris.get(walletId)) {
      try { mgr.connect(uri); } catch (e) { log(`wc[${walletId}] reconnect failed:`, e?.message); }
    }
    return mgr;
  }

  function stopForWallet(walletId) {
    const mgr = managers.get(walletId); if (!mgr) return;
    try { mgr.disconnectAll?.(); } catch {}
    managers.delete(walletId);
    uris.delete(walletId);
    origins.delete(walletId);
  }

  // `origin`: the verified page origin that asked to pair, or "panel" when
  // the user pasted the code into Aegis themselves.
  async function connectUri(walletId, uri, origin = "panel") {
    const mgr = managers.get(walletId);
    if (!mgr) throw new Error("wc: wallet not ready");
    const trimmed = String(uri || "").trim();
    if (!/^wiz:\/\//i.test(trimmed)) throw new Error("wc: URI must start with wiz://");
    const id = mgr.connect(trimmed);
    const set = uris.get(walletId) || new Set();
    set.add(trimmed);
    uris.set(walletId, set);
    const o = origins.get(walletId) || new Map();
    o.set(trimmed, { origin: String(origin || "panel"), at: Date.now() });
    origins.set(walletId, o);
    persist(walletId);
    fireStateChange();
    return id;
  }

  async function disconnect(walletId, connId) {
    const mgr = managers.get(walletId); if (!mgr) return;
    try { await mgr.disconnect(connId); } catch {}
    // Trim the persisted URI so the next start doesn't re-add it.
    const conn = [...(mgr.connections?.values?.() || [])].find((c) => c.id === connId);
    if (conn?.uri) {
      const set = uris.get(walletId); if (set) { set.delete(conn.uri); persist(walletId); }
    }
    fireStateChange();
  }

  // Revoking a site in Aegis also ends the WizardConnect pairings it made.
  async function disconnectOrigin(origin) {
    let n = 0;
    for (const [walletId, o] of origins) {
      const mgr = managers.get(walletId);
      for (const [uri, rec] of [...o]) {
        if (rec.origin !== origin) continue;
        const conn = mgr ? (typeof mgr.getConnections === "function" ? Object.values(mgr.getConnections() || {}) : []).find((c) => c.uri === uri) : null;
        if (conn) { try { await mgr.disconnect(conn.id); } catch {} }
        uris.get(walletId)?.delete(uri);
        o.delete(uri);
        persist(walletId);
        n++;
      }
    }
    if (n) fireStateChange();
    return n;
  }

  function snapshot() {
    const out = {};
    for (const [walletId, mgr] of managers) {
      // getConnections() is the documented accessor and returns a plain
      // {id: RelayConnectionState} record. We used to walk mgr.connections
      // (a private Map) directly, which works but is one library refactor
      // away from silently returning nothing.
      const states = typeof mgr.getConnections === "function"
        ? Object.values(mgr.getConnections() || {})
        : [...(mgr.connections?.values?.() || [])];
      const list = states.map((c) => ({
        id: c.id,
        uri: c.uri,
        // `label` is the library's own "dapp name once known, otherwise
        // Connecting…", so it's the right thing to show while a pairing
        // is still settling.
        label: c.label || null,
        dappName: c.dappName || null,
        dappIcon: c.dappIcon || null,
        pairedFrom: origins.get(walletId)?.get(c.uri)?.origin || null,
        // RelayStatus is an OBJECT: { status: "connected" | "reconnecting"
        // | "disconnected" | "session_deleted" }. Reading `.kind` (which
        // does not exist) fell through to String(object) and put the
        // literal "[object Object]" in the panel's status field.
        status: typeof c.status === "string"
          ? c.status
          : (c.status?.status || "unknown"),
        connectedAt: c.connectedAt || null,
      }));
      out[walletId] = list;
    }
    return out;
  }

  function onStateChange(fn) { listeners.add(fn); return () => listeners.delete(fn); }

  function cleanErrForDapp(e) {
    const m = String(e?.message || e);
    if (m === "cancelled") return "user rejected";
    return m.replace(/\n[\s\S]*$/, "").slice(0, 200);
  }

  return { startForWallet, stopForWallet, connectUri, disconnect, disconnectOrigin, snapshot, onStateChange };
};