const express = require('express');
const http = require('http');
const socketIo = require('socket.io');
const path = require('path');
const helmet = require('helmet');
const compression = require('compression');
const rateLimit = require('express-rate-limit');
const session = require('express-session');
const SQLiteStore = require('connect-sqlite3')(session);
const csrf = require('csurf');
const { spawn } = require('child_process');
const chokidar = require('chokidar');
const os = require('os');

// Import utilities
const paths = require('./utils/paths');
const ConfigParser = require('./utils/config-parser');
const ContentDBClient = require('./utils/contentdb');
const serverManager = require('./utils/shared-server-manager');

// Import middleware
const { requireAuth, attachUser } = require('./middleware/auth');
const { validateInput, xssProtection, additionalSecurityHeaders, validateRequestSize, pathTraversalProtection } = require('./middleware/security');

// Import routes
const authRouter = require('./routes/auth');
const usersRouter = require('./routes/users');
const worldsRouter = require('./routes/worlds');
const modsRouter = require('./routes/mods');
const serverRouter = require('./routes/server');
const configRouter = require('./routes/config');
const contentdbRouter = require('./routes/contentdb');
const extensionsRouter = require('./routes/extensions');
const { router: apiRouter, setSocketIO } = require('./routes/api');

const app = express();
const server = http.createServer(app);
const io = socketIo(server);

const PORT = process.env.PORT || 3000;

// Global server state
let serverProcess = null;
let serverStatus = 'stopped';
let logWatcher = null;

// Security and performance middleware
app.use(additionalSecurityHeaders);
app.use(helmet({
  contentSecurityPolicy: {
    directives: {
      defaultSrc: ["'self'"],
      styleSrc: ["'self'", "'unsafe-inline'"], // Allow inline styles for now
      scriptSrc: ["'self'", "'unsafe-inline'"], // Allow inline scripts for now
      imgSrc: ["'self'", "data:", "https:"],
      connectSrc: ["'self'", "ws:", "wss:"],
      formAction: ["'self'"],
      frameAncestors: ["'none'"]
    }
  }
}));
app.use(compression());
app.use(validateRequestSize);

// Rate limiting
const limiter = rateLimit({
  windowMs: 15 * 60 * 1000, // 15 minutes
  max: 1000 // limit each IP to 1000 requests per windowMs (increased for testing)
});
app.use(limiter);

// Session middleware
app.use(session({
  store: new SQLiteStore({
    db: 'sessions.db',
    dir: '.'
  }),
  secret: process.env.SESSION_SECRET || 'luanti-server-manager-secret-key-change-in-production',
  resave: false,
  saveUninitialized: false,
  cookie: {
    secure: process.env.NODE_ENV === 'production' && process.env.HTTPS === 'true',
    httpOnly: true,
    maxAge: 24 * 60 * 60 * 1000 // 24 hours
  }
}));

// Body parsing
app.use(express.json({ limit: '10mb' }));
app.use(express.urlencoded({ extended: true, limit: '10mb' }));

// Security middleware
app.use(pathTraversalProtection);
app.use(validateInput);
app.use(xssProtection);

// Authentication middleware
app.use(attachUser);

// CSRF protection middleware (only for non-API routes)
const csrfProtection = csrf();
app.use((req, res, next) => {
  // Skip CSRF for API routes and auth endpoints during setup
  if (req.path.startsWith('/api/') || 
      req.path.startsWith('/health') ||
      (req.path === '/login' && req.method === 'POST') ||
      (req.path === '/register' && req.method === 'POST')) {
    return next();
  }
  return csrfProtection(req, res, next);
});

// Make CSRF token and security functions available to all templates
app.use((req, res, next) => {
  res.locals.csrfToken = req.csrfToken ? req.csrfToken() : null;
  res.locals.escapeHtml = require('./middleware/security').escapeHtml;
  next();
});

// Static files
app.use('/static', express.static(path.join(__dirname, 'public')));

// Template engine
app.set('view engine', 'ejs');
app.set('views', path.join(__dirname, 'views'));

// Make utility functions available to templates
app.locals.formatDate = (date) => new Date(date).toLocaleString();
app.locals.formatFileSize = (bytes) => {
  if (bytes === 0) return '0 B';
  const k = 1024;
  const sizes = ['B', 'KB', 'MB', 'GB'];
  const i = Math.floor(Math.log(bytes) / Math.log(k));
  return parseFloat((bytes / Math.pow(k, i)).toFixed(2)) + ' ' + sizes[i];
};
app.locals.formatUptime = (uptime) => {
  if (!uptime) return 'N/A';
  const seconds = Math.floor(uptime / 1000);
  const minutes = Math.floor(seconds / 60);
  const hours = Math.floor(minutes / 60);
  
  if (hours > 0) {
    return `${hours}h ${minutes % 60}m ${seconds % 60}s`;
  } else if (minutes > 0) {
    return `${minutes}m ${seconds % 60}s`;
  } else {
    return `${seconds}s`;
  }
};

// Initialize API with Socket.IO
setSocketIO(io);

// Socket.IO connection handling
io.on('connection', (socket) => {
  console.log('Client connected:', socket.id);
  
  // Send current server status
  socket.emit('serverStatus', {
    status: serverStatus,
    pid: serverProcess ? serverProcess.pid : null,
    uptime: serverProcess ? Date.now() - serverProcess.startTime : 0
  });

  socket.on('disconnect', () => {
    console.log('Client disconnected:', socket.id);
  });
});

// Broadcast server status updates
function broadcastServerStatus() {
  io.emit('serverStatus', {
    status: serverStatus,
    pid: serverProcess ? serverProcess.pid : null,
    uptime: serverProcess ? Date.now() - serverProcess.startTime : 0
  });
}

// Broadcast log messages
function broadcastLog(logEntry) {
  io.emit('serverLog', logEntry);
}

// Authentication routes (public)
app.use('/', authRouter);

// API routes (require authentication)
app.use('/api', requireAuth, apiRouter);

// Protected routes (require authentication)
app.use('/users', requireAuth, usersRouter);
app.use('/worlds', requireAuth, worldsRouter);
app.use('/mods', requireAuth, modsRouter);
app.use('/server', requireAuth, serverRouter);
app.use('/config', requireAuth, configRouter);
app.use('/contentdb', requireAuth, contentdbRouter);
app.use('/extensions', requireAuth, extensionsRouter);

// Main dashboard route (protected)
app.get('/', requireAuth, async (req, res) => {
  try {
    paths.ensureDirectories();
    
    // Get basic stats for dashboard
    const fs = require('fs').promises;
    let worldCount = 0;
    let modCount = 0;
    
    try {
      const worldDirs = await fs.readdir(paths.worldsDir);
      worldCount = worldDirs.length;
    } catch {}
    
    try {
      const modDirs = await fs.readdir(paths.modsDir);
      modCount = modDirs.length;
    } catch {}
    
    const stats = {
      worlds: worldCount,
      mods: modCount,
      minetestDir: paths.minetestDir
    };
    
    const systemInfo = {
      platform: os.platform(),
      arch: os.arch(),
      nodeVersion: process.version
    };
    
    res.render('dashboard', { 
      title: 'LuHost Dashboard',
      stats: stats,
      systemInfo: systemInfo
    });
  } catch (error) {
    console.error('Error loading dashboard:', error);
    res.status(500).render('error', { 
      error: 'Failed to load dashboard',
      message: error.message 
    });
  }
});

// Health check endpoint
app.get('/health', (req, res) => {
  res.json({ 
    status: 'ok', 
    timestamp: new Date().toISOString(),
    minetestDir: paths.minetestDir,
    serverStatus: serverStatus
  });
});

// Error handling middleware
app.use((err, req, res, next) => {
  console.error(err.stack);
  res.status(500).render('error', { 
    error: 'Something went wrong!',
    message: err.message
  });
});

// 404 handler
app.use((req, res) => {
  res.status(404).render('error', { 
    error: 'Page not found',
    message: `The page ${req.url} does not exist.`
  });
});

// Server startup
server.listen(PORT, async () => {
  console.log(`LuHost Server running on http://localhost:${PORT}`);
  
  // Initialize paths with configuration
  try {
    await paths.initialize();
    console.log(`Luanti data directory: ${paths.minetestDir}`);
  } catch (error) {
    console.error('Failed to initialize paths:', error);
    console.log(`Using default Luanti directory: ${paths.minetestDir}`);
  }
  
  // Ensure minetest directories exist
  paths.ensureDirectories();
});

// Export for potential testing
module.exports = { app, server, io };