/**
 * Full server.js
 *
 * - Robust /api/yt/source -> resolves YouTube via VidFly (configurable via VIDFLY_API env)
 * - Debug endpoint /api/vidfly/debug -> calls VidFly and returns the raw JSON for debugging
 * - Robust /api/yt/proxy -> proxies googlevideo redirector URLs (for browser CORS + Range support)
 * - Full Socket.IO room handlers (join, set_track, play/pause/seek/ended, requests, admin commands)
 *
 * Notes:
 * - Set VIDFLY_API to override the default VidFly endpoint (default: https://api.vidfly.ai/api/media/youtube/download)
 * - This file is self-contained; keep your existing jiosaavn.js module alongside (imported)
 * - Be mindful of bandwidth when proxying large files through this server.
 */

import express from 'express';
import http from 'http';
import cors from 'cors';
import path from 'path';
import { fileURLToPath } from 'url';
import axios from 'axios';
import { PassThrough } from 'stream';
import { Server as SocketIOServer } from 'socket.io';

import {
  searchUniversal,
  getSong,
  getAlbum,
  getPlaylist,
  getLyrics
} from './jiosaavn.js'; // keep your module

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const app = express();
app.use(cors());
app.use(express.json());

function log(...args) { console.log(new Date().toISOString(), ...args); }
function short(v, n = 400) {
  try {
    const s = typeof v === 'string' ? v : JSON.stringify(v);
    return s.length > n ? s.slice(0, n) + '…' : s;
  } catch { return String(v).slice(0, n) + '…'; }
}

// ---------- Room state ----------
/*
room = {
  id, name, hostId,
  users: Map<socketId, { name, role: 'host'|'cohost'|'member', muted?: boolean }>,
  track: { url, title, meta, kind, thumb? },
  isPlaying, anchor, anchorAt,
  queue: Array<track>
}
*/
const rooms = new Map();
function ensureRoom(roomId) {
  if (!rooms.has(roomId)) {
    rooms.set(roomId, {
      id: roomId,
      name: null,
      hostId: null,
      users: new Map(),
      track: null,
      isPlaying: false,
      anchor: 0,
      anchorAt: 0,
      queue: []
    });
  }
  return rooms.get(roomId);
}
function currentState(room) {
  return {
    track: room.track,
    isPlaying: room.isPlaying,
    anchor: room.anchor,
    anchorAt: room.anchorAt,
    queue: room.queue
  };
}
function membersPayload(room) {
  return [...room.users.entries()].map(([id, u]) => ({
    id,
    name: u.name || 'Guest',
    role: u.role || 'member',
    muted: !!u.muted,
    isHost: id === room.hostId
  }));
}
function broadcastMembers(roomId) {
  const room = rooms.get(roomId);
  if (!room) return;
  const members = membersPayload(room);
  io.to(roomId).emit('members', { members, roomName: room.name || room.id });
}
function requireHostOrCohost(room, socketId) {
  const u = room.users.get(socketId);
  return (socketId === room.hostId) || (u && (u.role === 'cohost'));
}
function normalizeThumb(meta) {
  const candidates = [
    meta?.thumb,
    meta?.image,
    meta?.thumbnail,
    meta?.song_image,
    meta?.album_image,
    meta?.image_url,
    meta?.images?.cover,
    meta?.images?.[0]
  ].filter(Boolean);
  return candidates[0] || null;
}
function findUserByName(room, targetNameRaw) {
  if (!targetNameRaw) return null;
  const targetName = String(targetNameRaw).replace(/^@/, '').trim().toLowerCase();
  let candidate = null;
  for (const [id, u] of room.users.entries()) {
    const n = (u.name || '').toLowerCase();
    if (n === targetName) return { id, u };
    if (!candidate && n.startsWith(targetName)) candidate = { id, u };
  }
  if (candidate) return candidate;
  for (const [id, u] of room.users.entries()) {
    const n = (u.name || '').toLowerCase();
    if (n.includes(targetName)) return { id, u };
  }
  return null;
}

// Health
app.get('/healthz', (_req, res) => res.send('OK'));

// ---------- JioSaavn proxies ----------
app.get('/api/result', async (req, res) => {
  try {
    const q = req.query.q || '';
    const data = await searchUniversal(q);
    res.json(data);
  } catch (e) {
    log('/api/result error', e?.message || short(e?.response?.data));
    res.status(500).json({ error: e.message });
  }
});
app.get('/api/song', async (req, res) => {
  try {
    const q = req.query.q || '';
    const data = await getSong(q);
    res.json(data);
  } catch (e) { log('/api/song error', e?.message || short(e?.response?.data)); res.status(500).json({ error: e.message }); }
});
app.get('/api/album', async (req, res) => {
  try {
    const q = req.query.q || '';
    const data = await getAlbum(q);
    res.json(data);
  } catch (e) { log('/api/album error', e?.message || short(e?.response?.data)); res.status(500).json({ error: e.message }); }
});
app.get('/api/playlist', async (req, res) => {
  try {
    const q = req.query.q || '';
    const data = await getPlaylist(q);
    res.json(data);
  } catch (e) { log('/api/playlist error', e?.message || short(e?.response?.data)); res.status(500).json({ error: e.message }); }
});
app.get('/api/lyrics', async (req, res) => {
  try {
    const q = req.query.q || '';
    const data = await getLyrics(q);
    res.json(data);
  } catch (e) { log('/api/lyrics error', e?.message || short(e?.response?.data)); res.status(500).json({ error: e.message }); }
});

// ---------- YouTube search (optional) ----------
app.get('/api/ytsearch', async (req, res) => {
  try {
    const key = process.env.YT_API_KEY;
    if (!key) return res.status(501).json({ error: 'YouTube search unavailable: set YT_API_KEY env' });
    const q = req.query.q || '';
    const resp = await axios.get('https://www.googleapis.com/youtube/v3/search', {
      params: { key, q, part: 'snippet', type: 'video', maxResults: 12 },
      timeout: 10000
    });
    const items = (resp.data.items || []).map(it => ({
      videoId: it.id?.videoId,
      title: it.snippet?.title,
      channelTitle: it.snippet?.channelTitle,
      thumb: it.snippet?.thumbnails?.medium?.url || it.snippet?.thumbnails?.default?.url
    })).filter(x => x.videoId);
    res.json({ items });
  } catch (e) {
    log('/api/ytsearch error', e?.message || short(e?.response?.data));
    res.status(500).json({ error: e.message });
  }
});

// ---------- YouTube resolve via VidFly ----------
const VIDFLY_API = process.env.VIDFLY_API || 'https://api.vidfly.ai/api/media/youtube/download';

app.get('/api/vidfly/debug', async (req, res) => {
  // Debug endpoint: calls VidFly and returns raw response (JSON) for troubleshooting
  try {
    let raw = (req.query.url || '').trim();
    if (!raw) return res.status(400).json({ error: 'Missing url' });
    if (/^[a-zA-Z0-9_-]{11}$/.test(raw)) raw = `https://www.youtube.com/watch?v=${raw}`;

    const apiUrl = `${VIDFLY_API}?url=${encodeURIComponent(raw)}`;
    log('VIDFLY debug call ->', apiUrl);
    const resp = await axios.get(apiUrl, { timeout: 20000, validateStatus: () => true });
    // Return status and body so caller can inspect
    res.status(200).json({ status: resp.status, headers: resp.headers, data: resp.data });
  } catch (e) {
    log('/api/vidfly/debug error', e?.message ?? e);
    res.status(500).json({ error: e?.message ?? String(e) });
  }
});

app.get('/api/yt/source', async (req, res) => {
  // Primary resolver: call VidFly and return chosen playable url + metadata
  try {
    let raw = (req.query.url || '').trim();
    if (!raw) return res.status(400).json({ error: 'Missing url' });
    if (/^[a-zA-Z0-9_-]{11}$/.test(raw)) raw = `https://www.youtube.com/watch?v=${raw}`;

    const apiUrl = `${VIDFLY_API}?url=${encodeURIComponent(raw)}`;
    log('Calling VidFly API:', apiUrl);
    const resp = await axios.get(apiUrl, { timeout: 20000, validateStatus: () => true });
    const data = resp.data;

    if (!data || typeof data !== 'object') {
      log('/api/yt/source vidfly non-object response:', short(data, 1000));
      return res.status(502).json({ error: 'Invalid VidFly response', snippet: short(data, 1000) });
    }
    if (Number(data.code) !== 0 || !data.data || !Array.isArray(data.data.items)) {
      // include vidfly response to aid debugging
      log('/api/yt/source vidfly returned error shape:', short(data, 1000));
      return res.status(502).json({ error: 'Invalid VidFly API response', detail: data });
    }

    const items = data.data.items;
    // prefer progressive (video with audio), otherwise highest-res video-only, otherwise any
    const progressive = items.filter(f => f.type === 'video_with_audio')
      .sort((a, b) => (Number(b.height || 0) - Number(a.height || 0)))[0];
    const videoOnly = items.filter(f => f.type === 'video')
      .sort((a, b) => (Number(b.height || 0) - Number(a.height || 0)))[0];
    const anyItem = items.find(f => f.url);
    const chosen = progressive || videoOnly || anyItem;

    if (!chosen || !chosen.url) {
      log('/api/yt/source no playable item found:', short(items, 1200));
      return res.status(502).json({ error: 'No playable format found in VidFly API response', detail: data });
    }

    res.json({
      url: chosen.url,
      title: data.data.title || raw,
      thumbnail: data.data.cover || null,
      duration: data.data.duration || null,
      kind: chosen.type || 'video',
      format: {
        ext: chosen.ext || null,
        fps: chosen.fps || null,
        resolution: `${chosen.width || '?'}x${chosen.height || '?'}`,
        label: chosen.label || null
      }
    });
  } catch (e) {
    log('/api/yt/source unexpected error:', e?.response?.data ?? e?.message ?? String(e));
    res.status(500).json({ error: 'Failed to fetch from VidFly API', detail: e?.response?.data ?? e?.message ?? String(e) });
  }
});

/*
  /api/yt/proxy
  - Proxies direct signed googlevideo URLs (redirector.googlevideo.com / googlevideo.com).
  - Forwards Range header to support seeking.
  - Forwards upstream headers (content-type, content-length, content-range, accept-ranges).
  - Responds with CORS header.
*/
function isAllowedProxyHost(urlStr) {
  try {
    const u = new URL(urlStr);
    const host = u.hostname.toLowerCase();
    return host.endsWith('googlevideo.com') || host.endsWith('redirector.googlevideo.com');
  } catch {
    return false;
  }
}

app.get('/api/yt/proxy', async (req, res) => {
  try {
    const raw = (req.query.url || '').trim();
    if (!raw) return res.status(400).json({ error: 'Missing url' });

    if (!isAllowedProxyHost(raw)) {
      return res.status(400).json({ error: 'Proxy to this host is not allowed by server policy' });
    }

    const rangeHeader = req.headers.range || null;
    const requestHeaders = {
      'User-Agent': req.headers['user-agent'] || 'Mozilla/5.0 (Windows NT 10.0; Win64; x64)',
      'Accept': '*/*',
      'Referer': 'https://www.youtube.com/',
      ...(rangeHeader ? { Range: rangeHeader } : {})
    };

    log('/api/yt/proxy fetching', short(raw, 200), 'Range:', rangeHeader ? rangeHeader.slice(0,120) : 'none');

    const resp = await axios.get(raw, {
      responseType: 'stream',
      timeout: 20000,
      headers: requestHeaders,
      maxRedirects: 5,
      validateStatus: () => true
    });

    if (resp.status >= 400) {
      // try to capture a short snippet for debugging
      let snippet = '';
      try {
        const reader = resp.data;
        const chunk = await new Promise((resolve) => {
          let done = false;
          const onData = (c) => { if (!done) { done = true; cleanup(); resolve(c); } };
          const onEnd = () => { if (!done) { done = true; cleanup(); resolve(null); } };
          const onErr = () => { if (!done) { done = true; cleanup(); resolve(null); } };
          const cleanup = () => { reader.removeListener('data', onData); reader.removeListener('end', onEnd); reader.removeListener('error', onErr); };
          reader.once('data', onData);
          reader.once('end', onEnd);
          reader.once('error', onErr);
        });
        if (chunk) snippet = chunk.toString('utf8', 0, 800);
      } catch (xx) { /* ignore */ }

      log('/api/yt/proxy remote returned error status', resp.status, 'snippet:', short(snippet, 400));
      return res.status(502).json({ error: 'Remote returned error', status: resp.status, snippet: short(snippet, 800) });
    }

    // check content-type header for obvious non-media responses
    const ct = String(resp.headers['content-type'] || '').toLowerCase();
    if (ct.includes('text/html') || ct.includes('application/json') || ct.includes('text/plain')) {
      // read a small snippet then return 502
      let snippet = '';
      try {
        const reader = resp.data;
        const chunk = await new Promise((resolve) => {
          let done = false;
          const onData = (c) => { if (!done) { done = true; cleanup(); resolve(c); } };
          const onEnd = () => { if (!done) { done = true; cleanup(); resolve(null); } };
          const onErr = () => { if (!done) { done = true; cleanup(); resolve(null); } };
          const cleanup = () => { reader.removeListener('data', onData); reader.removeListener('end', onEnd); reader.removeListener('error', onErr); };
          reader.once('data', onData);
          reader.once('end', onEnd);
          reader.once('error', onErr);
        });
        if (chunk) snippet = chunk.toString('utf8', 0, 1600);
      } catch (xx) {}

      log('/api/yt/proxy remote returned non-media content-type', ct, short(snippet, 400));
      return res.status(502).json({ error: 'Remote returned non-media content-type', contentType: ct, snippet: short(snippet, 800) });
    }

    // forward useful headers
    const forwardable = ['content-type','content-length','content-range','accept-ranges','cache-control','last-modified','etag'];
    forwardable.forEach(h => {
      const v = resp.headers[h];
      if (v !== undefined) res.setHeader(h, v);
    });

    // CORS for browsers (already app.use(cors()) but explicitly set for stream)
    res.setHeader('Access-Control-Allow-Origin', '*');
    res.setHeader('Access-Control-Allow-Headers', 'Range,Accept,Content-Type');

    // status (206 or 200)
    res.status(resp.status);

    // pipe upstream stream directly to client (no peeking)
    const upstream = resp.data;
    upstream.on('error', (err) => {
      log('/api/yt/proxy upstream stream error:', err?.message || String(err));
      try {
        if (!res.headersSent) res.status(502).json({ error: 'Upstream stream error', detail: err?.message || String(err) });
        else res.destroy(err);
      } catch {}
    });
    upstream.pipe(res).on('error', (err) => {
      log('/api/yt/proxy pipe error:', err?.message || String(err));
      try { if (!res.headersSent) res.status(502).json({ error: 'Pipe error', detail: err?.message || String(err) }); } catch {}
    });

  } catch (e) {
    log('/api/yt/proxy unexpected error:', e?.response?.status ?? e?.message ?? String(e));
    const detail = e?.response?.data ?? e?.message ?? String(e);
    res.status(500).json({ error: 'Failed to proxy remote video', detail: short(detail, 800) });
  }
});

// ---------- Lobby ----------
app.get('/api/rooms', (_req, res) => {
  const data = [...rooms.values()]
    .filter(r => r.users.size > 0)
    .map(r => ({
      id: r.id,
      name: r.name || r.id,
      members: r.users.size,
      isPlaying: r.isPlaying
    }));
  res.json({ rooms: data });
});
app.get('/api/ping', (_req, res) => res.json({ ok: true }));

// ---------- Static client ----------
const clientDir = path.resolve(__dirname, '../client/dist');
app.use(express.static(clientDir));
app.get('*', (_req, res) => res.sendFile(path.join(clientDir, 'index.html')));

// ---------- Socket.IO ----------
const server = http.createServer(app);
const io = new SocketIOServer(server, {
  cors: { origin: '*', methods: ['GET', 'POST'] }
});

io.on('connection', (socket) => {
  let joinedRoom = null;

  socket.on('join_room', ({ roomId, name, asHost = false, roomName = null }, ack) => {
    const room = ensureRoom(roomId);

    if (asHost || !room.hostId) room.hostId = socket.id;
    if (!room.name && roomName) room.name = String(roomName).trim().slice(0, 60) || null;

    const role = socket.id === room.hostId ? 'host' : 'member';
    const cleanName = String(name || 'Guest').slice(0, 40);
    room.users.set(socket.id, { name: cleanName, role });

    socket.join(roomId);
    joinedRoom = roomId;

    ack?.({
      roomId,
      isHost: socket.id === room.hostId,
      state: currentState(room),
      roomName: room.name || room.id
    });

    // Single clean system message to everyone
    io.to(roomId).emit('system', { text: `System: ${cleanName} has joined the chat` });
    broadcastMembers(roomId);
  });

  socket.on('rename', ({ roomId, newName }) => {
    const room = rooms.get(roomId);
    if (!room) return;
    const u = room.users.get(socket.id);
    if (!u) return;
    u.name = String(newName || 'Guest').slice(0, 40);
    broadcastMembers(roomId);
  });

  socket.on('chat_message', ({ roomId, name, text }) => {
    const room = rooms.get(roomId);
    if (!room) return;
    const u = room.users.get(socket.id);
    if (!u) return;
    if (u.muted) {
      socket.emit('system', { text: 'System: You are muted by the host' });
      return;
    }
    socket.to(roomId).emit('chat_message', { name, text, at: Date.now() });
  });

  // /play request (user requests a song; host/cohost get notified)
  socket.on('song_request', ({ roomId, requester, query }) => {
    const room = rooms.get(roomId);
    if (!room) return;
    const payload = { requester, query, at: Date.now(), requestId: `${Date.now()}_${Math.random().toString(36).slice(2)}` };
    for (const [id, usr] of room.users.entries()) {
      if (id === room.hostId || usr.role === 'cohost') io.to(id).emit('song_request', payload);
    }
    io.to(roomId).emit('system', { text: `System: ${requester} requested /play ${query}` });
  });

  // Host handles request action
  socket.on('song_request_action', ({ roomId, action, track }) => {
    const room = rooms.get(roomId);
    if (!room) return;
    if (!requireHostOrCohost(room, socket.id)) return;
    if ((action === 'accept' || action === 'queue') && track) {
      const t = {
        url: track.url,
        title: track.title || track.url,
        meta: track.meta || {},
        kind: track.kind || 'audio',
        thumb: track.thumb || normalizeThumb(track.meta || {})
      };
      if (action === 'accept') {
        room.track = t;
        room.isPlaying = false;
        room.anchor = 0;
        room.anchorAt = Date.now();
        io.to(roomId).emit('set_track', { track: room.track });
        io.to(roomId).emit('pause', { anchor: 0, anchorAt: room.anchorAt });
        io.to(roomId).emit('system', { text: `System: Now playing ${room.track.title}` });
      } else {
        room.queue.push(t);
        io.to(roomId).emit('queue_update', { queue: room.queue });
        io.to(roomId).emit('system', { text: `System: Queued ${t.title}` });
      }
    }
  });

  // Host/cohost controls
  socket.on('set_track', ({ roomId, track }) => {
    const room = rooms.get(roomId);
    if (!room || !requireHostOrCohost(room, socket.id)) return;
    const thumb = track.thumb || normalizeThumb(track.meta || {});
    room.track = { ...track, thumb };
    room.isPlaying = false;
    room.anchor = 0;
    room.anchorAt = Date.now();
    io.to(roomId).emit('set_track', { track: room.track });
    io.to(roomId).emit('pause', { anchor: 0, anchorAt: room.anchorAt });
    io.to(roomId).emit('system', { text: `System: Selected ${room.track.title || room.track.url}` });
  });

  socket.on('play', ({ roomId }) => {
    const room = rooms.get(roomId);
    if (!room || !requireHostOrCohost(room, socket.id)) return;
    room.isPlaying = true;
    room.anchorAt = Date.now();
    io.to(roomId).emit('play', { anchor: room.anchor, anchorAt: room.anchorAt });
  });

  socket.on('pause', ({ roomId }) => {
    const room = rooms.get(roomId);
    if (!room || !requireHostOrCohost(room, socket.id)) return;
    const elapsed = Math.max(0, Date.now() - room.anchorAt) / 1000;
    if (room.isPlaying) room.anchor += elapsed;
    room.isPlaying = false;
    room.anchorAt = Date.now();
    io.to(roomId).emit('pause', { anchor: room.anchor, anchorAt: room.anchorAt });
  });

  socket.on('seek', ({ roomId, to }) => {
    const room = rooms.get(roomId);
    if (!room || !requireHostOrCohost(room, socket.id)) return;
    room.anchor = to;
    room.anchorAt = Date.now();
    io.to(roomId).emit('seek', { anchor: room.anchor, anchorAt: room.anchorAt, isPlaying: room.isPlaying });
  });

  // Ended -> auto next
  socket.on('ended', ({ roomId }) => {
    const room = rooms.get(roomId);
    if (!room || !requireHostOrCohost(room, socket.id)) return;
    const next = room.queue.shift();
    if (next) {
      const thumb = next.thumb || normalizeThumb(next.meta || {});
      room.track = { ...next, thumb };
      room.isPlaying = false;
      room.anchor = 0;
      room.anchorAt = Date.now();
      io.to(roomId).emit('set_track', { track: room.track });
      io.to(roomId).emit('pause', { anchor: 0, anchorAt: room.anchorAt });
      io.to(roomId).emit('queue_update', { queue: room.queue });
      io.to(roomId).emit('system', { text: `System: Now playing ${room.track.title}` });
    } else {
      io.to(roomId).emit('system', { text: 'System: Queue ended' });
    }
  });

  // Admin commands: kick/promote/mute
  socket.on('admin_command', ({ roomId, cmd, targetName }) => {
    const room = rooms.get(roomId);
    if (!room) return;
    const actor = room.users.get(socket.id);
    if (!actor || !(socket.id === room.hostId || actor.role === 'cohost')) return;

    const found = findUserByName(room, targetName);
    if (!found) {
      io.to(socket.id).emit('system', { text: `System: User @${targetName} not found` });
      return;
    }

    if (cmd === 'kick') {
      const { id } = found;
      io.to(id).emit('system', { text: 'System: You were kicked by the host' });
      io.sockets.sockets.get(id)?.leave(roomId);
      room.users.delete(id);
      io.to(roomId).emit('system', { text: `System: ${found.u.name} was kicked` });
      broadcastMembers(roomId);
    } else if (cmd === 'promote') {
      found.u.role = 'cohost';
      io.to(roomId).emit('system', { text: `System: ${found.u.name} was promoted to co-host` });
      broadcastMembers(roomId);
    } else if (cmd === 'mute') {
      found.u.muted = true;
      io.to(roomId).emit('system', { text: `System: ${found.u.name} was muted` });
      broadcastMembers(roomId);
    }
  });

  // Sync request: client asks for current room state
  socket.on('sync_request', ({ roomId }, ack) => {
    const room = rooms.get(roomId);
    if (!room) return;
    ack?.(currentState(room));
  });

  socket.on('disconnect', () => {
    if (!joinedRoom) return;
    const room = rooms.get(joinedRoom);
    if (!room) return;
    const leftUser = room.users.get(socket.id);
    room.users.delete(socket.id);
    if (socket.id === room.hostId) {
      const nextHost = [...room.users.keys()][0];
      room.hostId = nextHost || null;
      if (room.hostId) {
        const u = room.users.get(room.hostId);
        if (u) u.role = 'host';
      }
      io.to(joinedRoom).emit('host_changed', { hostId: room.hostId });
    }
    if (leftUser) {
      const nm = leftUser.name || 'User';
      io.to(joinedRoom).emit('system', { text: `System: ${nm} has left the chat` });
    }
    if (room.users.size === 0) rooms.delete(joinedRoom);
    else broadcastMembers(joinedRoom);
  });
});

// start server
const PORT = process.env.PORT || 3000;
server.listen(PORT, () => {
  log(`Server running on port ${PORT}`);
});