const express = require('express');
const path = require('path');
const fs = require('fs');
const { spawn } = require('child_process');
const { createProxyMiddleware } = require('http-proxy-middleware');

const app = express();
const PORT = Number(process.env.PORT) || 4000;
const ARCHIVES_DIR = path.join(__dirname, '..', 'archives');
const gameProcs = [];
const tunnelProcs = [];
const tunnelUrls = {};
const gamePorts = {};

const useHosting = process.argv.includes('--host') || process.env.HOSTING === 'true' || process.env.HOST === 'true';

function loadEntries() {
  const entries = [];
  const dirs = fs.readdirSync(ARCHIVES_DIR, { withFileTypes: true });
  for (const d of dirs) {
    if (!d.isDirectory()) continue;
    const metaPath = path.join(ARCHIVES_DIR, d.name, 'archive.json');
    if (!fs.existsSync(metaPath)) continue;
    try {
      const entry = JSON.parse(fs.readFileSync(metaPath, 'utf8'));
      entries.push(entry);
    } catch (e) {
      console.error(`Skipping ${d.name}: ${e.message}`);
    }
  }
  entries.sort((a, b) => new Date(b.date) - new Date(a.date));
  return entries;
}

function getEntry(id) {
  return loadEntries().find(e => e.id === id);
}

function mapEntryUrl(entry) {
  const port = gamePorts[entry.id] || entry.port;
  if (port) {
    if (useHosting && tunnelUrls[port]) {
      return { ...entry, url: tunnelUrls[port] };
    }
    return { ...entry, url: `/play/${entry.id}` };
  }
  return entry;
}

function startTunnel(port) {
  return new Promise((resolve, reject) => {
    console.log(`[tunnel] Starting cloudflared tunnel for port ${port}...`);
    const proc = spawn('cloudflared', ['tunnel', '--url', `http://localhost:${port}`]);
    let resolved = false;

    tunnelProcs.push(proc);

    const timer = setTimeout(() => {
      if (!resolved) {
        resolved = true;
        reject(new Error(`cloudflared tunnel for port ${port} timed out after 15 seconds`));
      }
    }, 15000);

    const handleData = (data) => {
      const text = data.toString();
      const match = text.match(/https:\/\/[a-zA-Z0-9-]+\.trycloudflare\.com/);
      if (match && !resolved) {
        resolved = true;
        clearTimeout(timer);
        const url = match[0];
        console.log(`[tunnel] Tunnel established for port ${port} -> ${url}`);
        resolve(url);
      }
    };

    proc.stdout.on('data', handleData);
    proc.stderr.on('data', handleData);

    proc.on('error', (err) => {
      if (!resolved) {
        resolved = true;
        clearTimeout(timer);
        reject(new Error(`Failed to start cloudflared: ${err.message}`));
      }
    });

    proc.on('exit', (code) => {
      if (!resolved) {
        resolved = true;
        clearTimeout(timer);
        reject(new Error(`cloudflared exited with code ${code} before establishing tunnel`));
      }
    });
  });
}

const refererProxies = {};

function getRefererProxy(port) {
  if (!refererProxies[port]) {
    refererProxies[port] = createProxyMiddleware({
      target: `http://localhost:${port}`,
      changeOrigin: true,
      logLevel: 'silent',
    });
  }
  return refererProxies[port];
}

// 1. Redirect /play/:id to /play/:id/ to ensure proper relative asset resolution and set active_game cookie
app.use((req, res, next) => {
  const match = req.path.match(/^\/play\/([^\/]+)/);
  if (match) {
    const gameId = match[1];
    const isSecure = req.secure || req.headers['x-forwarded-proto'] === 'https';
    res.cookie('active_game', gameId, {
      path: '/',
      sameSite: isSecure ? 'none' : 'lax',
      secure: isSecure
    });
    if (req.path === `/play/${gameId}`) {
      return res.redirect(301, `${req.path}/`);
    }
  }
  next();
});

// Helper to extract game ID from referer or cookies
function getGameId(req) {
  const referer = req.headers.referer || '';
  
  // 1. Try to extract game ID directly from Referer (e.g. /play/rblx/...)
  const refMatch = referer.match(/\/play\/([^\/]+)/);
  if (refMatch) {
    return refMatch[1];
  }

  // 2. Determine if the referer is the main portal page (path is exactly "/")
  let isPortal = false;
  if (referer) {
    try {
      const refUrl = new URL(referer);
      if (refUrl.pathname === '/') {
        isPortal = true;
      }
    } catch (e) {
      // Ignore URL parsing errors
    }
  }

  // 3. Fallback to cookie if we are not on the portal page
  if (!isPortal) {
    const cookieHeader = req.headers.cookie || '';
    const cookieMatch = cookieHeader.match(/(?:^|; )active_game=([^;]*)/);
    if (cookieMatch) {
      return cookieMatch[1];
    }
  }

  return null;
}

// 2. Referer/Cookie-based HTTP proxy for absolute paths (e.g. /css/..., /js/..., /api/...)
app.use((req, res, next) => {
  if (req.path === '/ws') return next();
  if (req.path.startsWith('/api/entries') || req.path.startsWith('/archives') || req.path.startsWith('/play/')) {
    return next();
  }
  const gameId = getGameId(req);
  if (gameId) {
    const port = gamePorts[gameId];
    if (port) {
      const proxy = getRefererProxy(port);
      return proxy(req, res, next);
    }
  }
  next();
});

// 3. WS Proxy specifically for WebSocket connections to /ws
const wsProxy = createProxyMiddleware({
  target: 'http://localhost:3000', // dummy fallback, overridden by router
  router: (req) => {
    const gameId = getGameId(req);
    if (gameId) {
      const port = gamePorts[gameId];
      if (port) {
        return `http://localhost:${port}`;
      }
    }
    return undefined;
  },
  changeOrigin: true,
  ws: true,
  logLevel: 'silent',
  on: {
    error: (err, req, res) => {
      console.error('[ws-proxy] error:', err);
    }
  }
});
app.use('/ws', wsProxy);

app.use('/archives', express.static(ARCHIVES_DIR));
app.use(express.static(path.join(__dirname, '..', 'public')));

app.get('/api/entries', (req, res) => {
  res.json(loadEntries().map(mapEntryUrl));
});

app.get('/api/entries/:id', (req, res) => {
  const entry = getEntry(req.params.id);
  if (!entry) return res.status(404).json({ error: 'not found' });
  res.json(mapEntryUrl(entry));
});

function serveIndex(req, res) {
  res.sendFile(path.join(__dirname, '..', 'public', 'index.html'));
}

async function startGameServers() {
  const entries = loadEntries();
  let nextPort = 3001;
  const tunnelPromises = [];

  for (const entry of entries) {
    const gameDir = path.join(ARCHIVES_DIR, entry.id, 'app');
    const serverEntry = path.join(gameDir, 'server', 'index.js');
    if (!fs.existsSync(serverEntry)) continue;
    const port = entry.port || nextPort;
    nextPort = Math.max(nextPort, port) + 1;
    gamePorts[entry.id] = port;

    const proc = spawn('node', ['server/index.js'], {
      cwd: gameDir,
      stdio: 'pipe',
      env: { ...process.env, PORT: String(port) },
    });
    proc.stdout.on('data', d => process.stdout.write(`[${entry.id}] ${d}`));
    proc.stderr.on('data', d => process.stderr.write(`[${entry.id}] ${d}`));
    proc.on('error', err => console.error(`[${entry.id}] failed:`, err.message));
    proc.on('exit', (code) => {
      if (code !== 0) console.error(`[${entry.id}] exited with code ${code}`);
    });
    gameProcs.push(proc);

    app.use(`/play/${entry.id}`, createProxyMiddleware({
      target: `http://localhost:${port}`,
      changeOrigin: true,
    }));

    console.log(`[proxy] /play/${entry.id} -> http://localhost:${port}`);

    if (useHosting) {
      const tunnelPromise = startTunnel(port)
        .then(url => {
          tunnelUrls[port] = url;
        })
        .catch(err => {
          console.error(`[${entry.id}] Tunnel error: ${err.message}`);
        });
      tunnelPromises.push(tunnelPromise);
    }
  }

  if (useHosting && tunnelPromises.length > 0) {
    console.log('[tunnel] Waiting for all game tunnels to be established...');
    await Promise.all(tunnelPromises);
    console.log('[tunnel] All game tunnels established!');
  }
}

function cleanup() {
  for (const proc of gameProcs) proc.kill();
  for (const proc of tunnelProcs) proc.kill();
}

function listen(port) {
  const srv = app.listen(port);
  srv.on('upgrade', wsProxy.upgrade);
  srv.on('error', (err) => {
    if (err.code === 'EADDRINUSE') {
      console.log(`port ${port} busy, trying ${port + 1}`);
      listen(port + 1);
    } else {
      throw err;
    }
  });
  srv.on('listening', async () => {
    const actualPort = srv.address().port;
    console.log('');
    console.log(`  ✦ AI Archives`);
    console.log(`  ✦ running at http://localhost:${actualPort}`);

    if (useHosting) {
      try {
        const portalUrl = await startTunnel(actualPort);
        tunnelUrls[actualPort] = portalUrl;
        console.log('');
        console.log(`  ✦ Public Portal URL: ${portalUrl}`);
        console.log('');
      } catch (err) {
        console.error(`  ✦ Failed to start portal tunnel: ${err.message}`);
        console.log('');
      }
    } else {
      console.log('');
    }

    await startGameServers();

    app.use(serveIndex);
  });
}

process.on('SIGINT', () => { cleanup(); process.exit(); });
process.on('SIGTERM', () => { cleanup(); process.exit(); });
process.on('exit', cleanup);

listen(PORT);