/**
 * CHAMPIONS OF LUNERARIA - Portal & Control Center Server
 * Production-ready, zero-dependency Node.js HTTP server with REST APIs,
 * Server-Sent Events (SSE) for live telemetry, and static asset streaming.
 */

const http = require('http');
const fs = require('fs');
const path = require('path');
const url = require('url');
const telemetry = require('./src/data/telemetry');

const PORT = parseInt(process.env.PORT, 10) || 8080;
const PUBLIC_DIR = path.join(__dirname, 'public');

const MIME_TYPES = {
  '.html': 'text/html; charset=UTF-8',
  '.css': 'text/css; charset=UTF-8',
  '.js': 'application/javascript; charset=UTF-8',
  '.json': 'application/json; charset=UTF-8',
  '.png': 'image/png',
  '.jpg': 'image/jpeg',
  '.jpeg': 'image/jpeg',
  '.gif': 'image/gif',
  '.svg': 'image/svg+xml',
  '.ico': 'image/x-icon',
  '.mp4': 'video/mp4',
  '.ttf': 'font/ttf',
  '.otf': 'font/otf',
  '.woff': 'font/woff',
  '.woff2': 'font/woff2'
};

// Connected SSE clients for live metrics push
const sseClients = new Set();

// Broadcast SSE update every 2 seconds
setInterval(() => {
  if (sseClients.size === 0) return;
  const payload = JSON.stringify(telemetry.getLiveMetrics());
  sseClients.forEach(res => {
    try {
      res.write(`data: ${payload}\n\n`);
    } catch (e) {
      sseClients.delete(res);
    }
  });
}, 2000);

const server = http.createServer((req, res) => {
  const parsedUrl = url.parse(req.url, true);
  const pathname = parsedUrl.pathname;

  // CORS headers
  res.setHeader('Access-Control-Allow-Origin', '*');
  res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS');
  res.setHeader('Access-Control-Allow-Headers', 'Content-Type');

  if (req.method === 'OPTIONS') {
    res.writeHead(204);
    res.end();
    return;
  }

  // ------------------------------------------------------------------------
  // API Routes
  // ------------------------------------------------------------------------
  if (pathname === '/api/metrics' && req.method === 'GET') {
    res.writeHead(200, { 'Content-Type': 'application/json' });
    res.end(JSON.stringify(telemetry.getLiveMetrics()));
    return;
  }

  if (pathname === '/api/benchmarks' && req.method === 'GET') {
    res.writeHead(200, { 'Content-Type': 'application/json' });
    res.end(JSON.stringify(telemetry.getBenchmarks()));
    return;
  }

  if (pathname === '/api/downloads/history' && req.method === 'GET') {
    res.writeHead(200, { 'Content-Type': 'application/json' });
    res.end(JSON.stringify(telemetry.getDailyDownloads()));
    return;
  }

  if (pathname === '/api/logs' && req.method === 'GET') {
    res.writeHead(200, { 'Content-Type': 'application/json' });
    res.end(JSON.stringify(telemetry.getLogs()));
    return;
  }

  // Server-Sent Events (SSE) Live Feed
  if (pathname === '/api/events' && req.method === 'GET') {
    res.writeHead(200, {
      'Content-Type': 'text/event-stream',
      'Cache-Control': 'no-cache',
      'Connection': 'keep-alive'
    });
    res.write(`data: ${JSON.stringify(telemetry.getLiveMetrics())}\n\n`);
    sseClients.add(res);

    req.on('close', () => {
      sseClients.delete(res);
    });
    return;
  }

  // Operations Control APIs (POST)
  if (pathname.startsWith('/api/control/') && req.method === 'POST') {
    let body = '';
    req.on('data', chunk => { body += chunk; });
    req.on('end', () => {
      let data = {};
      try { if (body) data = JSON.parse(body); } catch (e) {}

      if (pathname === '/api/control/tickrate') {
        const newRate = telemetry.setTickrate(data.rate || 20);
        res.writeHead(200, { 'Content-Type': 'application/json' });
        res.end(JSON.stringify({ success: true, targetTickrate: newRate }));
        return;
      }

      if (pathname === '/api/control/maintenance') {
        const mode = telemetry.toggleMaintenance();
        res.writeHead(200, { 'Content-Type': 'application/json' });
        res.end(JSON.stringify({ success: true, maintenanceMode: mode }));
        return;
      }

      if (pathname === '/api/control/spike') {
        const newBaseline = telemetry.simulateSpike(data.amount || 25);
        res.writeHead(200, { 'Content-Type': 'application/json' });
        res.end(JSON.stringify({ success: true, ccuBaseline: newBaseline }));
        return;
      }

      if (pathname === '/api/control/broadcast') {
        const msg = data.message || 'Server-Ankündigung';
        telemetry.addLog('WARN', 'BROADCAST', msg);
        res.writeHead(200, { 'Content-Type': 'application/json' });
        res.end(JSON.stringify({ success: true, message: msg }));
        return;
      }

      res.writeHead(404, { 'Content-Type': 'application/json' });
      res.end(JSON.stringify({ error: 'Unknown control action' }));
    });
    return;
  }

  // ------------------------------------------------------------------------
  // Static Page Routes
  // ------------------------------------------------------------------------
  let filePath = '';
  if (pathname === '/' || pathname === '/index.html') {
    filePath = path.join(PUBLIC_DIR, 'index.html');
  } else if (pathname === '/dashboard' || pathname === '/dashboard.html') {
    filePath = path.join(PUBLIC_DIR, 'dashboard.html');
  } else {
    filePath = path.join(PUBLIC_DIR, pathname);
  }

  // Security: prevent directory traversal
  if (!filePath.startsWith(PUBLIC_DIR)) {
    res.writeHead(403);
    res.end('Access Denied');
    return;
  }

  fs.stat(filePath, (err, stats) => {
    if (err || !stats.isFile()) {
      res.writeHead(404, { 'Content-Type': 'text/plain; charset=UTF-8' });
      res.end('404 Not Found - Champions of Luneraria');
      return;
    }

    const ext = path.extname(filePath).toLowerCase();
    const contentType = MIME_TYPES[ext] || 'application/octet-stream';

    // Support video streaming (HTTP 206 Partial Content)
    if (ext === '.mp4') {
      const range = req.headers.range;
      const fileSize = stats.size;

      if (range) {
        const parts = range.replace(/bytes=/, '').split('-');
        const start = parseInt(parts[0], 10);
        const end = parts[1] ? parseInt(parts[1], 10) : fileSize - 1;
        const chunksize = (end - start) + 1;
        const fileStream = fs.createReadStream(filePath, { start, end });

        res.writeHead(206, {
          'Content-Range': `bytes ${start}-${end}/${fileSize}`,
          'Accept-Ranges': 'bytes',
          'Content-Length': chunksize,
          'Content-Type': 'video/mp4'
        });
        fileStream.pipe(res);
        return;
      }
    }

    // Standard static file response
    res.writeHead(200, {
      'Content-Type': contentType,
      'Content-Length': stats.size,
      'Cache-Control': ext === '.html' ? 'no-cache' : 'public, max-age=86400'
    });
    fs.createReadStream(filePath).pipe(res);
  });
});

server.listen(PORT, '0.0.0.0', () => {
  console.log('===============================================================');
  console.log(` ⚔️  CHAMPIONS OF LUNERARIA - PORTAL & CONTROL CENTER READY`);
  console.log('===============================================================');
  console.log(` 🌐 Öffentliche Website:  http://localhost:${PORT}/`);
  console.log(` 🎛️  Schaltzentrale / Ops:  http://localhost:${PORT}/dashboard`);
  console.log(` 📊 Live Telemetrie API:  http://localhost:${PORT}/api/metrics`);
  console.log(` 📈 Benchmarks API:       http://localhost:${PORT}/api/benchmarks`);
  console.log('---------------------------------------------------------------');
});