server.js

// Load environment variables from .env file
require('dotenv').config();

// Import required packages
const express = require('express');
const mongoose = require('mongoose');
const cors = require('cors');

// Import route files
const authRoutes = require('./authRoutes');
const productRoutes = require('./productRoutes');
const cartRoutes = require('./cartRoutes');

// Middleware: Handle errors
const errorHandler = (err, req, res, next) => {
  console.error('Error:', err);
  res.status(err.statusCode || 500).json({
    success: false,
    message: err.message || 'Server Error'
  });
};

// Middleware: Handle 404 errors
const notFound = (req, res, next) => {
  res.status(404).json({
    success: false,
    message: `Route ${req.originalUrl} not found`
  });
};

// Step 1: Initialize Express application
const app = express();

// Step 2: Connect to MongoDB database
mongoose.connect(process.env.MONGODB_URI)
  .then(() => console.log('MongoDB Connected'))
  .catch(err => {
    console.error('Database connection error:', err);
    process.exit(1);
  });

// Step 3: Setup middleware
app.use(cors());  // Allow cross-origin requests
app.use(express.json());  // Parse JSON request bodies
app.use(express.urlencoded({ extended: true }));  // Parse URL-encoded bodies

// Step 4: Define routes
// Welcome route - shows API information
app.get('/', (req, res) => {
  res.json({
    success: true,
    message: 'Welcome to ShoppyGlobe API',
    version: '1.0.0',
    endpoints: {
      auth: '/api/auth',
      products: '/api/products',
      cart: '/api/cart'
    }
  });
});

// API Routes
app.use('/api/auth', authRoutes);        // Authentication routes (register, login)
app.use('/api/products', productRoutes);  // Product routes (get products)
app.use('/api/cart', cartRoutes);        // Cart routes (protected - requires login)

// Step 5: Error handling (must be at the end)
app.use(notFound);       // Handle 404 errors
app.use(errorHandler);   // Handle all other errors

// Step 6: Start the server
const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
  console.log(`Server running on port ${PORT}`);
});

module.exports = app;