// Import required modules
const express = require('express');
const bodyParser = require('body-parser');
const mongoose = require('mongoose');

// Create the Express application
const app = express();
const PORT = process.env.PORT || 3000;

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

// Connect to MongoDB using Mongoose
const MONGODB_URI = 'mongodb://localhost:27017/ecommerce_db'; // Replace with your MongoDB URI
mongoose.connect(MONGODB_URI, {
  useNewUrlParser: true,
  useUnifiedTopology: true,
});

// Create Mongoose Schema and Model for Products
const productSchema = new mongoose.Schema({
  name: { type: String, required: true },
  price: { type: Number, required: true },
  category: { type: mongoose.Schema.Types.ObjectId, ref: 'Category' },
});

const Product = mongoose.model('Product', productSchema);

// Create Mongoose Schema and Model for Categories
const categorySchema = new mongoose.Schema({
  name: { type: String, required: true },
});

const Category = mongoose.model('Category', categorySchema);

// Create Mongoose Schema and Model for Orders
const orderSchema = new mongoose.Schema({
  products: [{ type: mongoose.Schema.Types.ObjectId, ref: 'Product' }],
  totalAmount: { type: Number, required: true },
  // Add other order-related fields as needed
});

const Order = mongoose.model('Order', orderSchema);

// Endpoints

// Products
app.get('/products', async (req, res) => {
  try {
    const products = await Product.find().populate('category', 'name');
    res.json(products);
  } catch (error) {
    res.status(500).json({ message: 'Error fetching products', error: error.message });
  }
});

app.get('/products/:id', async (req, res) => {
  try {
    const product = await Product.findById(req.params.id).populate('category', 'name');
    if (!product) {
      return res.status(404).json({ message: 'Product not found' });
    }
    res.json(product);
  } catch (error) {
    res.status(500).json({ message: 'Error fetching product', error: error.message });
  }
});

app.post('/products', async (req, res) => {
  try {
    const { name, price, category } = req.body;
    const product = new Product({ name, price, category });
    await product.save();
    res.status(201).json(product);
  } catch (error) {
    res.status(500).json({ message: 'Error creating product', error: error.message });
  }
});

app.put('/products/:id', async (req, res) => {
  try {
    const { name, price, category } = req.body;
    const product = await Product.findByIdAndUpdate(
      req.params.id,
      { name, price, category },
      { new: true }
    ).populate('category', 'name');
    if (!product) {
      return res.status(404).json({ message: 'Product not found' });
    }
    res.json(product);
  } catch (error) {
    res.status(500).json({ message: 'Error updating product', error: error.message });
  }
});

app.delete('/products/:id', async (req, res) => {
  try {
    const product = await Product.findByIdAndRemove(req.params.id);
    if (!product) {
      return res.status(404).json({ message: 'Product not found' });
    }
    res.json({ message: 'Product deleted successfully' });
  } catch (error) {
    res.status(500).json({ message: 'Error deleting product', error: error.message });
  }
});

// Categories
app.get('/categories', async (req, res) => {
  try {
    const categories = await Category.find();
    res.json(categories);
  } catch (error) {
    res.status(500).json({ message: 'Error fetching categories', error: error.message });
  }
});

app.get('/categories/:id', async (req, res) => {
  try {
    const category = await Category.findById(req.params.id);
    if (!category) {
      return res.status(404).json({ message: 'Category not found' });
    }
    res.json(category);
  } catch (error) {
    res.status(500).json({ message: 'Error fetching category', error: error.message });
  }
});

app.post('/categories', async (req, res) => {
  try {
    const { name } = req.body;
    const category = new Category({ name });
    await category.save();
    res.status(201).json(category);
  } catch (error) {
    res.status(500).json({ message: 'Error creating category', error: error.message });
  }
});

app.put('/categories/:id', async (req, res) => {
  try {
    const { name } = req.body;
    const category = await Category.findByIdAndUpdate(
      req.params.id,
      { name },
      { new: true }
    );
    if (!category) {
      return res.status(404).json({ message: 'Category not found' });
    }
    res.json(category);
  } catch (error) {
    res.status(500).json({ message: 'Error updating category', error: error.message });
  }
});

app.delete('/categories/:id', async (req, res) => {
  try {
    const category = await Category.findByIdAndRemove(req.params.id);
    if (!category) {
      return res.status(404).json({ message: 'Category not found' });
    }
    res.json({ message: 'Category deleted successfully' });
  } catch (error) {
    res.status(500).json({ message: 'Error deleting category', error: error.message });
  }
});

// Start the server
app.listen(PORT, () => {
  console.log(`Server is running on port ${PORT}`);
});