const Cart = require('../model/Cart');

exports.addToCart = async (req, res) => {
  const { userId } = req.body;
  const { productId, quantity } = req.body;

  try {
    let cart = await Cart.findOne({ userId });

    if (!cart) {
      cart = new Cart({
        userId,
        items: [{ productId, quantity }],
      });
    } else {
      const existingItem = cart.items.find(item => item.productId.toString() === productId);

      if (existingItem) {
        existingItem.quantity += quantity;
      } else {
        cart.items.push({ productId, quantity });
      }
    }

    await cart.save();

    res.json({ message: 'Item added to cart successfully' });
  } catch (error) {
    console.error(error);
    res.status(500).json({ error: 'Internal Server Error' });
  }
};

exports.updateQuantity = async (req, res) => {
  const { userId, productId, quantity } = req.body;

  try {
    let cart = await Cart.findOne({ userId });

    if (!cart) {
      return res.status(404).json({ error: 'Cart not found for the user' });
    }

    const existingItem = cart.items.find(item => item.productId.toString() === productId);

    if (!existingItem) {
      return res.status(404).json({ error: 'Product not found in the cart' });
    }

    existingItem.quantity = quantity;

    await cart.save();

    res.json({ message: 'Quantity updated successfully' });
  } catch (error) {
    console.error(error);
    res.status(500).json({ error: 'Internal Server Error' });
  }
};

exports.removeFromCart = async (req, res) => {
  const { userId, productId } = req.body;

  try {
    let cart = await Cart.findOne({ userId });

    if (!cart) {
      return res.status(404).json({ error: 'Cart not found for the user' });
    }

    cart.items = cart.items.filter(item => item.productId.toString() !== productId);

    await cart.save();

    res.json({ message: 'Product removed from cart successfully' });
  } catch (error) {
    console.error(error);
    res.status(500).json({ error: 'Internal Server Error' });
  }
};

exports.getCartDetails = async (req, res) => {
  const { userId } = req.body;

  try {
    const cart = await Cart.findOne({ userId }).populate('items.productId', 'name price');

    if (!cart) {
      return res.status(404).json({ error: 'Cart not found for the user' });
    }

    // Calculate subtotal for each item
    const itemsWithSubtotal = cart.items.map(item => ({
      ...item.toObject(),
      subtotal: item.quantity * item.productId.price,
    }));

    // Calculate total price for all items
    const totalPrice = itemsWithSubtotal.reduce((total, item) => total + item.subtotal, 0);

    res.json({
      items: itemsWithSubtotal,
      totalPrice,
    });
  } catch (error) {
    console.error(error);
    res.status(500).json({ error: 'Internal Server Error' });
  }
};