const Cart = require('../models/cartModel');
const Product = require('../models/productModel');
// add to cart function
exports.addToCart = async (req, res) => {
  try {
    const userId = req.user.id;
    const { productId, quantity } = req.body;

    const product = await Product.findById(productId);
    if (!product) {
      return res.status(404).json({ message: 'Product not found' });
    }
    let cart = await Cart.findOne({ user: userId });

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

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

    // Populate product details before returning
    await cart.populate({
      path: 'items.product',
      select: 'nameAr nameEn price salePrice imageCover stock',
    });

    res.status(200).json({
      status: 'success',
      message: 'Product added to cart',
      cart,
    });
  } catch (err) {
    res
      .status(500)
      .json({ message: 'Failed to add product', error: err.message });
  }
};

exports.getCart = async (req, res) => {
  try {
    const userId = req.user.id;

    // Find the cart associated with the user
    const cart = await Cart.findOne({ user: userId }).populate({
      path: 'items.product',
      select: 'nameAr nameEn price salePrice imageCover',
    });

    if (!cart || cart.items.length === 0) {
      return res.status(200).json({
        status: 'success',
        message: 'Cart is empty',
        cart: { items: [] },
      });
    }

    // Calculate the total price
    const totalPrice = cart.items.reduce((acc, item) => {
      const price = item.product.salePrice || item.product.price;
      return acc + price * item.quantity;
    }, 0);

    res.status(200).json({
      status: 'success',
      cart,
      totalPrice,
    });
  } catch (err) {
    res
      .status(500)
      .json({ message: 'Failed to fetch cart', error: err.message });
  }
};

// PATCH /samoulla/v1/cart/update-quantity
exports.updateQuantity = async (req, res) => {
  try {
    const userId = req.user.id;
    const { productId, action } = req.body;

    const cart = await Cart.findOne({ user: userId }).populate({
      path: 'items.product',
      select: 'nameAr nameEn price salePrice imageCover',
    });

    if (!cart) {
      return res.status(404).json({ message: 'Cart not found' });
    }

    const cartItem = cart.items.find(
      (el) => el.product._id.toString() === productId,
    );

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

    if (action === 'increase') {
      cartItem.quantity += 1;
    } else if (action === 'decrease') {
      cartItem.quantity -= 1;

      if (cartItem.quantity <= 0) {
        cart.items = cart.items.filter(
          (el) => el.product._id.toString() !== productId,
        );
      }
    } else {
      return res.status(400).json({ message: 'Invalid action' });
    }

    await cart.save();

    const totalPrice = cart.items.reduce((acc, item) => {
      const price = item.product.salePrice || item.product.price;
      return acc + price * item.quantity;
    }, 0);

    res.status(200).json({
      status: 'success',
      cart,
      totalPrice,
    });
  } catch (err) {
    res
      .status(500)
      .json({ message: 'Error updating quantity', error: err.message });
  }
};

// PATCH /samoulla/v1/cart/update-quantity
// {
//   "productId": "ID_OF_PRODUCT",
//   "action": "increase"
// }
// {
//   "productId": "ID_OF_PRODUCT",
//   "action": "decrease"
// }

// DELETE /samoulla/v1/cart/remove-item
exports.removeFromCart = async (req, res) => {
  try {
    const userId = req.user.id;
    const { productId } = req.params;

    const cart = await Cart.findOne({ user: userId }).populate({
      path: 'items.product',
      select: 'nameAr nameEn price salePrice imageCover',
    });

    if (!cart) {
      return res.status(404).json({ message: 'Cart not found' });
    }

    const itemExists = cart.items.find(
      (el) => el.product._id.toString() === productId,
    );

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

    cart.items = cart.items.filter(
      (el) => el.product._id.toString() !== productId,
    );

    await cart.save();

    const totalPrice = cart.items.reduce((acc, item) => {
      const price = item.product.salePrice || item.product.price;
      return acc + price * item.quantity;
    }, 0);

    res.status(200).json({
      status: 'success',
      message: 'Product removed from cart',
      cart,
      totalPrice,
    });
  } catch (err) {
    res
      .status(500)
      .json({ message: 'Error removing product', error: err.message });
  }
};

exports.clearCart = async (req, res) => {
  try {
    const cart = await Cart.findOne({ user: req.user._id });

    if (!cart) {
      return res.status(404).json({ message: 'Cart not found' });
    }

    cart.items = [];
    await cart.save();

    res.status(200).json({
      status: 'success',
      message: 'Cart cleared successfully',
      cart,
    });
  } catch (err) {
    res
      .status(500)
      .json({ message: 'Something went wrong', error: err.message });
  }
};

// GET /samoulla/v1/cart/all (Admin only)
exports.getAllCarts = async (req, res) => {
  try {
    // Find all carts that are not empty and belong to a user
    const carts = await Cart.find({
      user: { $exists: true, $ne: null },
      items: { $exists: true, $not: { $size: 0 } },
    })
      .populate({
        path: 'user',
        select: 'name email phone',
      })
      .populate({
        path: 'items.product',
        select: 'nameAr nameEn price salePrice imageCover',
      })
      .sort('-updatedAt');

    res.status(200).json({
      status: 'success',
      results: carts.length,
      data: {
        carts,
      },
    });
  } catch (err) {
    res.status(500).json({
      status: 'error',
      message: 'Failed to fetch carts',
      error: err.message,
    });
  }
};
// DELETE /samoulla/v1/cart/:id (Admin only)
exports.deleteCart = async (req, res) => {
  try {
    const cart = await Cart.findByIdAndDelete(req.params.id);

    if (!cart) {
      return res.status(404).json({
        status: 'fail',
        message: 'No cart found with that ID',
      });
    }

    res.status(204).json({
      status: 'success',
      data: null,
    });
  } catch (err) {
    res.status(500).json({
      status: 'error',
      message: 'Failed to delete cart',
      error: err.message,
    });
  }
};