import express from 'express'
import { createServer } from 'http'
import { Server } from 'socket.io'
import cors from 'cors'
import helmet from 'helmet'
import compression from 'compression'
import morgan from 'morgan'
import dotenv from 'dotenv'
import path from 'path'

// Load environment variables
dotenv.config()

// Import routes and middleware
import authRoutes from './routes/auth'
import userRoutes from './routes/users'
import chatRoutes from './routes/chats'
import messageRoutes from './routes/messages'
import uploadRoutes from './routes/upload'
import adminRoutes from './routes/admin'

// Import middleware
import { errorHandler } from './middleware/errorHandler'
import { rateLimiter } from './middleware/rateLimiter'
import { authMiddleware } from './middleware/auth'

// Import socket handlers
import { setupSocketHandlers } from './socket'

// Import database
import { initializeDatabase } from './config/database'

const app = express()
const server = createServer(app)

// Initialize Socket.IO
const io = new Server(server, {
  cors: {
    origin: process.env.CORS_ORIGIN || "http://localhost:5173",
    methods: ["GET", "POST"],
    credentials: true
  },
  transports: ['websocket', 'polling']
})

// Middleware
app.use(helmet({
  crossOriginEmbedderPolicy: false,
  contentSecurityPolicy: {
    directives: {
      defaultSrc: ["'self'"],
      styleSrc: ["'self'", "'unsafe-inline'"],
      scriptSrc: ["'self'"],
      imgSrc: ["'self'", "data:", "https:"],
    },
  },
}))

app.use(cors({
  origin: process.env.CORS_ORIGIN || "http://localhost:5173",
  credentials: true
}))

app.use(compression())
app.use(morgan('combined'))
app.use(express.json({ limit: '10mb' }))
app.use(express.urlencoded({ extended: true, limit: '10mb' }))

// Rate limiting
app.use(rateLimiter)

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

// Health check
app.get('/health', (req, res) => {
  res.json({ 
    status: 'OK', 
    timestamp: new Date().toISOString(),
    uptime: process.uptime()
  })
})

// API Routes
app.use('/api/auth', authRoutes)
app.use('/api/users', authMiddleware, userRoutes)
app.use('/api/chats', authMiddleware, chatRoutes)
app.use('/api/messages', authMiddleware, messageRoutes)
app.use('/api/upload', authMiddleware, uploadRoutes)
app.use('/api/admin', authMiddleware, adminRoutes)

// 404 handler
app.use('*', (req, res) => {
  res.status(404).json({
    success: false,
    error: 'Route not found'
  })
})

// Error handling middleware
app.use(errorHandler)

// Setup Socket.IO handlers
setupSocketHandlers(io)

// Initialize database and start server
async function startServer() {
  try {
    // Initialize database connection
    await initializeDatabase()
    console.log('Database connected successfully')

    const PORT = process.env.PORT || 3001
    const HOST = process.env.HOST || 'localhost'

    server.listen(PORT, () => {
      console.log(`🚀 Server running on http://${HOST}:${PORT}`)
      console.log(`📡 Socket.IO server ready`)
      console.log(`🌍 Environment: ${process.env.NODE_ENV || 'development'}`)
    })
  } catch (error) {
    console.error('Failed to start server:', error)
    process.exit(1)
  }
}

// Graceful shutdown
process.on('SIGTERM', () => {
  console.log('SIGTERM received, shutting down gracefully')
  server.close(() => {
    console.log('Server closed')
    process.exit(0)
  })
})

process.on('SIGINT', () => {
  console.log('SIGINT received, shutting down gracefully')
  server.close(() => {
    console.log('Server closed')
    process.exit(0)
  })
})

// Handle uncaught exceptions
process.on('uncaughtException', (error) => {
  console.error('Uncaught Exception:', error)
  process.exit(1)
})

process.on('unhandledRejection', (reason, promise) => {
  console.error('Unhandled Rejection at:', promise, 'reason:', reason)
  process.exit(1)
})

startServer()

export { app, server, io }