index.js

const express = require("express");
const mongoose = require("mongoose");
const dotenv = require("dotenv");
const cors = require("cors");
const swaggerUi = require('swagger-ui-express');
const swaggerDocument = require('./swagger.json');

dotenv.config();

const app = express();

// Middleware
app.use(express.json());
app.use(express.urlencoded({ extended: true }));

// CORS - Allow all origins with preflight handling
app.use(cors({
  origin: true, // Allow all origins
  methods: ['GET', 'POST', 'PUT', 'DELETE', 'PATCH', 'OPTIONS'],
  allowedHeaders: ['Origin', 'X-Requested-With', 'Content-Type', 'Accept', 'Authorization', 'Cache-Control'],
  credentials: false,
  preflightContinue: false,
  optionsSuccessStatus: 200
}));

// Additional CORS handling for preflight requests
// app.options('/*', cors()); // Removed due to Express 5.x compatibility

// Manual CORS headers for all requests (backup)
app.use((req, res, next) => {
  res.header('Access-Control-Allow-Origin', '*');
  res.header('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE, PATCH, OPTIONS');
  res.header('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept, Authorization, Cache-Control');
  res.header('Access-Control-Max-Age', '86400');
  
  if (req.method === 'OPTIONS') {
    res.status(200).end();
    return;
  }
  
  next();
});

// MongoDB Connection with retry logic for Render
const connectDB = async () => {
  try {
    const conn = await mongoose.connect(process.env.MONGO_URI);
    console.log(`✅ MongoDB connected: ${conn.connection.host}`);
  } catch (error) {
    console.error("❌ MongoDB connection error:", error);
    process.exit(1);
  }
};

connectDB();

// Import Routes
const authRoutes = require("./routes/authRoutes");
const vehicleRoutes = require("./routes/vehicleRoutes");
const dealerRoutes = require("./routes/dealerRoutes");
const promotionRoutes = require("./routes/promotionRoutes");
const customerRoutes = require("./routes/customerRoutes");
const orderRoutes = require("./routes/orderRoutes");
const inventoryRoutes = require("./routes/inventoryRoutes");
const reportRoutes = require("./routes/reportRoutes");
const quoteRoutes = require("./routes/quoteRoutes");
const testDriveRoutes = require("./routes/testDriveRoutes");
const contractRoutes = require("./routes/contractRoutes");
const paymentRoutes = require("./routes/paymentRoutes");
const vehicleModelRoutes = require("./routes/vehicleModelRoutes");
const vehicleColorRoutes = require("./routes/vehicleColorRoutes");
const deliveryRoutes = require("./routes/deliveryRoutes");
const feedbackRoutes = require("./routes/feedbackRoutes");
const dashboardRoutes = require("./routes/dashboardRoutes");
const userRoutes = require("./routes/userRoutes");
const vehicleRequestRoutes = require("./routes/vehicleRequestRoutes");
const installmentPlanRoutes = require("./routes/installmentPlanRoutes");
const dealerContractRoutes = require("./routes/dealerContractRoutes");

// Use Routes
app.use("/api/auth", authRoutes);
app.use("/api/vehicles", vehicleRoutes);
app.use("/api/dealers", dealerRoutes);
app.use("/api/promotions", promotionRoutes);
app.use("/api/customers", customerRoutes);
app.use("/api/orders", orderRoutes);
app.use("/api/inventory", inventoryRoutes);
app.use("/api/reports", reportRoutes);
app.use("/api/quotes", quoteRoutes);
app.use("/api/test-drives", testDriveRoutes);
app.use("/api/contracts", contractRoutes);
app.use("/api/payments", paymentRoutes);
app.use("/api/vehicle-models", vehicleModelRoutes);
app.use("/api/vehicle-colors", vehicleColorRoutes);
app.use("/api/deliveries", deliveryRoutes);
app.use("/api/feedbacks", feedbackRoutes);
app.use("/api/dashboard", dashboardRoutes);
app.use("/api/users", userRoutes);
app.use("/api/vehicle-requests", vehicleRequestRoutes);
app.use("/api/installment-plans", installmentPlanRoutes);
app.use("/api/dealer-contracts", dealerContractRoutes);

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

// Root endpoint
app.get('/', (req, res) => {
  res.json({
    message: 'Electric Vehicle Dealer Management System API',
    version: '1.0.0',
    documentation: '/api-docs',
    health: '/health',
    endpoints: {
      auth: '/api/auth',
      vehicles: '/api/vehicles',
      dealers: '/api/dealers',
      customers: '/api/customers',
      orders: '/api/orders',
      inventory: '/api/inventory',
      quotes: '/api/quotes',
      promotions: '/api/promotions',
      reports: '/api/reports'
    }
  });
});

// Swagger Documentation
app.use('/api-docs', swaggerUi.serve, swaggerUi.setup(swaggerDocument, {
  customCss: '.swagger-ui .topbar { display: none }',
  customSiteTitle: "EVM API Documentation",
  swaggerOptions: {
    persistAuthorization: true,
    displayRequestDuration: true,
    docExpansion: 'none',
    filter: true,
    showExtensions: true,
    showCommonExtensions: true
  }
}));

// 404 handler
app.use((req, res) => {
  res.status(404).json({
    error: 'Route not found',
    message: `Cannot ${req.method} ${req.originalUrl}`
  });
});

// Global error handler
app.use((err, req, res, next) => {
  console.error(err.stack);
  res.status(500).json({
    error: 'Something went wrong!',
    message: process.env.NODE_ENV === 'production' ? 'Internal server error' : err.message
  });
});

// Start Server
const PORT = process.env.PORT || 5000;
const server = app.listen(PORT, '0.0.0.0', () => {
  console.log(`🚀 Server running on port ${PORT}`);
  console.log(`📚 API Documentation: http://localhost:${PORT}/api-docs`);
  console.log(`🏥 Health Check: http://localhost:${PORT}/health`);
  console.log(`🌍 Environment: ${process.env.NODE_ENV || 'development'}`);
});

// Graceful shutdown for Render
process.on('SIGTERM', () => {
  console.log('SIGTERM received. Shutting down gracefully...');
  server.close(() => {
    console.log('Process terminated');
    mongoose.connection.close();
  });
});

process.on('SIGINT', () => {
  console.log('SIGINT received. Shutting down gracefully...');
  server.close(() => {
    console.log('Process terminated');
    mongoose.connection.close();
  });
});