const express = require('express');
const cors = require('cors');
const helmet = require('helmet');
const morgan = require('morgan');
const compression = require('compression');
const rateLimit = require('express-rate-limit');
const { createServer } = require('http');
const { Server } = require('socket.io');
require('dotenv').config();

const { sequelize } = require('./models');
const routes = require('./routes');
const { initializeSocketHandlers } = require('./services/socketService');
const errorHandler = require('./middleware/errorHandler');

const app = express();
const server = createServer(app);
const io = new Server(server, {
  cors: {
    origin: process.env.CORS_ORIGIN || "http://localhost:3000",
    methods: ["GET", "POST", "PUT", "DELETE"]
  }
});

// Rate limiting
const limiter = rateLimit({
  windowMs: parseInt(process.env.RATE_LIMIT_WINDOW_MS) || 15 * 60 * 1000, // 15 minutes
  max: parseInt(process.env.RATE_LIMIT_MAX_REQUESTS) || 100,
  message: 'Too many requests from this IP, please try again later.'
});

// Middleware
app.use(helmet());
app.use(compression());
app.use(morgan('combined'));
app.use(cors({
  origin: process.env.CORS_ORIGIN || "http://localhost:3000",
  credentials: true
}));
app.use(express.json({ limit: '10mb' }));
app.use(express.urlencoded({ extended: true }));
app.use('/api/', limiter);

// Make io available to routes
app.use((req, res, next) => {
  req.io = io;
  next();
});

// Routes
app.use('/api', routes);

// Health check endpoints
app.get('/health', (req, res) => {
  res.status(200).json({ 
    status: 'OK', 
    timestamp: new Date().toISOString(),
    environment: process.env.NODE_ENV 
  });
});

app.use('/api/health', require('./routes/health'));

// Error handling
app.use(errorHandler);

// Socket.IO initialization
initializeSocketHandlers(io);

const PORT = process.env.PORT || 3001;

// Database connection and server startup
async function startServer() {
  try {
    await sequelize.authenticate();
    console.log('Database connected successfully.');
    
    if (process.env.NODE_ENV !== 'production') {
      await sequelize.sync({ alter: true });
      console.log('Database synchronized.');
    }
    
    server.listen(PORT, () => {
      console.log(`Server running on port ${PORT}`);
      console.log(`Environment: ${process.env.NODE_ENV}`);
    });
  } catch (error) {
    console.error('Unable to start server:', error);
    process.exit(1);
  }
}

startServer();

module.exports = { app, server, io };