server.js

const http = require('http');
const fs = require('fs');
const path = require('path');
const url = require('url');

// Try to load WebSocket module, fallback if not available
let WebSocket = null;
let isWebSocketAvailable = false;
try {
  WebSocket = require('ws');
  isWebSocketAvailable = true;
  console.log('WebSocket support enabled');
} catch (error) {
  console.log('WebSocket support disabled (ws package not installed)');
  console.log('Install with: npm install ws');
}

const DIST_DIR = path.join(__dirname, 'dist');
const CLIENT_DIR = path.join(__dirname, 'client');
const LOG_DIR = path.join(__dirname, 'logs');
// Check if IS_PRODUCTION is set to true
const isProduction = process.env.IS_PRODUCTION === 'true';
// In production mode, dist directory must exist
if (isProduction && !fs.existsSync(DIST_DIR)) {
  throw new Error(`Production mode enabled but dist directory does not exist: ${DIST_DIR}`);
}
// Force port 3000 in production, otherwise use PORT environment variable or default to 3000
const PORT = isProduction ? 3000 : (process.env.PORT || 3000);

// Track connected WebSocket clients
const wsClients = new Set();

// MIME types for different file extensions
const mimeTypes = {
  '.html': 'text/html',
  '.js': 'text/javascript',
  '.css': 'text/css',
  '.json': 'application/json',
  '.png': 'image/png',
  '.jpg': 'image/jpeg',
  '.jpeg': 'image/jpeg',
  '.gif': 'image/gif',
  '.svg': 'image/svg+xml',
  '.ico': 'image/x-icon',
  '.woff': 'font/woff',
  '.woff2': 'font/woff2',
  '.ttf': 'font/ttf',
  '.eot': 'application/vnd.ms-fontobject'
};

// Get MIME type based on file extension
function getMimeType(filePath) {
  const ext = path.extname(filePath).toLowerCase();
  return mimeTypes[ext] || 'text/plain';
}

// Serve static files
function serveFile(filePath, res) {
  fs.readFile(filePath, (err, data) => {
    if (err) {
      res.writeHead(404, { 'Content-Type': 'text/plain' });
      res.end('File not found');
      return;
    }

    const mimeType = getMimeType(filePath);
    res.writeHead(200, { 'Content-Type': mimeType });
    res.end(data);
  });
}

// Handle POST requests
function handlePostRequest(req, res, parsedUrl) {
  if (parsedUrl.pathname === '/message') {
    let body = '';

    req.on('data', chunk => {
      body += chunk.toString();
    });

    req.on('end', () => {
      try {
        const data = JSON.parse(body);
        const message = data.message;

        if (!message) {
          res.writeHead(400, { 'Content-Type': 'application/json' });
          res.end(JSON.stringify({ error: 'Message is required' }));
          return;
        }

        // Check if WebSocket is available
        if (!isWebSocketAvailable) {
          res.writeHead(503, { 'Content-Type': 'application/json' });
          res.end(JSON.stringify({
            error: 'WebSocket functionality not available',
            details: 'Install the ws package with: npm install ws'
          }));
          return;
        }

        // Broadcast message to all connected WebSocket clients
        wsClients.forEach(client => {
          if (client.readyState === WebSocket.OPEN) {
            client.send(JSON.stringify({ type: 'message', message: message }));
          }
        });

        res.writeHead(200, { 'Content-Type': 'application/json' });
        res.end(JSON.stringify({ success: true, clientCount: wsClients.size }));

      } catch (error) {
        res.writeHead(400, { 'Content-Type': 'application/json' });
        res.end(JSON.stringify({ error: 'Invalid JSON' }));
      }
    });
  } else if (parsedUrl.pathname === '/log') {
    let body = '';

    req.on('data', chunk => {
      body += chunk.toString();
    });

    req.on('end', () => {
      try {
        const data = JSON.parse(body);
        const message = data.message;

        if (message === undefined || message === null) {
          res.writeHead(400, { 'Content-Type': 'application/json' });
          res.end(JSON.stringify({ error: 'Message is required' }));
          return;
        }

        const logPath = path.join(LOG_DIR, 'user_actions.log');
        const logEntry = String(message) + '\n';

        fs.appendFile(logPath, logEntry, (err) => {
          if (err) {
            console.error('Error writing to log file:', err);
            res.writeHead(500, { 'Content-Type': 'application/json' });
            res.end(JSON.stringify({ error: 'Failed to write log' }));
            return;
          }

          res.writeHead(200, { 'Content-Type': 'application/json' });
          res.end(JSON.stringify({ success: true }));
        });
      } catch (error) {
        res.writeHead(400, { 'Content-Type': 'application/json' });
        res.end(JSON.stringify({ error: 'Invalid JSON' }));
      }
    });
  } else {
    res.writeHead(404, { 'Content-Type': 'text/plain' });
    res.end('Not found');
  }
}

function initializeLogsDirectory() {
  try {
    if (!fs.existsSync(LOG_DIR)) {
      fs.mkdirSync(LOG_DIR, { recursive: true });
    }
  } catch (error) {
    console.error('Error creating logs directory:', error);
  }
}

// Create HTTP server
const server = http.createServer((req, res) => {
  const parsedUrl = url.parse(req.url, true);
  let pathName = parsedUrl.pathname === '/' ? '/index.html' : parsedUrl.pathname;

  // Handle POST requests
  if (req.method === 'POST') {
    handlePostRequest(req, res, parsedUrl);
    return;
  }

  // Serve static files: production from dist, development from client
  const staticDir = isProduction ? DIST_DIR : CLIENT_DIR;
  let filePath = path.join(staticDir, pathName.replace(/^\/+/, ''));

  // Security check - prevent directory traversal
  const resolvedStaticDir = path.resolve(staticDir);
  const resolvedFilePath = path.resolve(filePath);
  const relativePath = path.relative(resolvedStaticDir, resolvedFilePath);

  if (relativePath.startsWith('..')) {
    res.writeHead(403, { 'Content-Type': 'text/plain' });
    res.end('Forbidden');
    return;
  }

  serveFile(filePath, res);
});

// Create WebSocket server only if WebSocket is available
// Note: WebSocket upgrade handling is performed automatically by the ws library
// when attached to the HTTP server. The HTTP request handler should NOT send
// a response for upgrade requests - the ws library handles the upgrade internally.
if (isWebSocketAvailable) {
  const wss = new WebSocket.Server({
    server,
    path: '/ws'
  });

  wss.on('connection', (ws, req) => {
    console.log('New WebSocket client connected');
    wsClients.add(ws);

    ws.on('close', () => {
      console.log('WebSocket client disconnected');
      wsClients.delete(ws);
    });

    ws.on('error', (error) => {
      console.error('WebSocket error:', error);
      wsClients.delete(ws);
    });
  });
}

// Initialize logs directory at startup
initializeLogsDirectory();

// Start server
server.listen(PORT, () => {
  console.log(`Server running at http://localhost:${PORT}`);
  if (isProduction) {
    console.log(`Serving static files from: ${DIST_DIR}`);
  } else {
    console.log(`Serving static files from: ${CLIENT_DIR}`);
  }
  if (isWebSocketAvailable) {
    console.log(`WebSocket server running on /ws`);
  } else {
    console.log(`WebSocket functionality disabled - install 'ws' package to enable`);
  }
  console.log('Press Ctrl+C to stop the server');
});

// Handle server errors
server.on('error', (err) => {
  if (err.code === 'EADDRINUSE') {
    console.error(`Port ${PORT} is already in use. Please try a different port.`);
  } else {
    console.error('Server error:', err);
  }
  process.exit(1);
});

// Graceful shutdown
process.on('SIGINT', () => {
  console.log('\nShutting down server...');
  server.close(() => {
    console.log('Server closed');
    process.exit(0);
  });
});