const User = require("../models/userModel.js");
const asyncHandler = require("express-async-handler");
const generateToken = require("../utils/generateToken.js");
const jwt = require("jsonwebtoken");

const createUser = async (req, res, next) => {
  const { name, email, password, dateOfBirth, gender, country } = req.body;
  console.log('User registration attempt:', { name, email, dateOfBirth, gender, country });

  if (!name || !email || !password) {
    res.status(400);
    const err = new Error("Please provide name, email and password");
    return next(err);
  }

  if (password.length < 6) {
    res.status(400);
    const err = new Error("Password must be atleast 6 characters");
    return next(err);
  }

  const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
  if (!emailRegex.test(email)) {
    res.status(400);
    const err = new Error("Invalid email address");
    return next(err);
  }

  try {
    
    const userExists = await User.findOne({ email });
    if (userExists) {
      res.status(400);
      const err = new Error(
        "Email is already registered. Please use a different email address"
      );
      return next(err);
    }

    const user = await User.create({
      name,
      email,
      password,
      dateOfBirth: dateOfBirth || '',
      gender: gender || '',
      country: country || '',
      createdAt: new Date(),
    });

    if (user) {
      
      const token = jwt.sign({ userId: user._id }, process.env.JWT_SECRET_KEY, {
        expiresIn: "10d",
      });

      generateToken(res, user._id);

      res.status(201).json({
        _id: user._id,
        name: user.name,
        email: user.email,
        dateOfBirth: user.dateOfBirth,
        gender: user.gender,
        country: user.country,
        token: token, 
      });
    }
  } catch (error) {
    console.log(error);
    if (error.code === 11000) {
      res.status(400);
      const err = new Error(
        "Email is already registered. Please use a different email address..."
      );
      return next(err);
    }
    res.status(500).json({ error: error.message } || "Internal server error");
  }
};

const login = asyncHandler(async (req, res) => {
  const { email, password } = req.body;
  console.log('Login attempt for:', email);

  const user = await User.findOne({ email });

  if (user && (await user.checkPassword(password))) {
    console.log('Password check passed for user:', user._id);

    try {
      await User.findByIdAndUpdate(user._id, {
        $set: { isActive: true, lastLogin: new Date() }
      });
    } catch (e) {
      console.error('Failed to update user active state/lastLogin:', e);
    }

    try {
      const token = jwt.sign({ userId: user._id }, process.env.JWT_SECRET_KEY, {
        expiresIn: "10d",
      });
      console.log('Token generated successfully:', token ? 'YES' : 'NO');
      console.log('JWT_SECRET_KEY exists:', !!process.env.JWT_SECRET_KEY);

      generateToken(res, user._id);

      const responseData = {
        _id: user._id,
        name: user.name,
        email: user.email,
        dateOfBirth: user.dateOfBirth,
        gender: user.gender,
        country: user.country,
        token: token, 
      };
      
      console.log('Sending response with token:', !!responseData.token);
      res.status(200).json(responseData);
    } catch (tokenError) {
      console.error('Error generating token:', tokenError);
      res.status(500).json({ error: 'Failed to generate authentication token' });
    }
  } else {
    console.log('Login failed for:', email);
    res.status(400);
    throw new Error("Invalid email or password");
  }
});

const logout = asyncHandler(async (req, res) => {
  const isProduction = process.env.NODE_ENV === 'production';
  
  try {
    if (req.user?._id) {
      await User.findByIdAndUpdate(req.user._id, { $set: { isActive: false } });
    }
  } catch (e) {
    console.error('Failed to mark user inactive on logout:', e);
  }
  
  const cookieOptions = {
    httpOnly: true,
    expires: new Date(0),
    path: '/',
    sameSite: isProduction ? 'none' : 'lax',
    secure: isProduction,
    ...(isProduction && process.env.COOKIE_DOMAIN && {
      domain: process.env.COOKIE_DOMAIN
    })
  };
  
  res.cookie("token", "", cookieOptions);
  res.status(200).json({ message: "Logged out.." });
});

const getProfile = asyncHandler(async (req, res) => {
  const user = {
    _id: req.user._id,
    name: req.user.name,
    email: req.user.email,
    dateOfBirth: req.user.dateOfBirth,
    gender: req.user.gender,
    country: req.user.country,
  };
  res.status(200).json(user);
});

const updateProfile = asyncHandler(async (req, res) => {
  const { password } = req.body;

  if (password && password.length < 6) { 
    res.status(400);
    throw new Error("Password must be at least 6 characters");
  }

  const user = await User.findById(req.user._id);
  if (user) {
    user.name = req.body.name || user.name;
    if (password) {
      user.password = password;
    }
    const updatedUser = await user.save();
    res.status(200).json({
      _id: updatedUser._id,
      name: updatedUser.name,
      email: updatedUser.email,
    });
  } else {
    res.status(404);
    throw new Error("User not found.");
  }
});

const getWishlist = asyncHandler(async (req, res) => {
  if (!req.user || !req.user._id) {
    return res.status(401).json({ message: "Not authorized, user not found" });
  }
  const user = await User.findById(req.user._id).populate("wishlist");
  res.json({ wishlist: user.wishlist });
});

const createWishlistItem = asyncHandler(async (req, res) => {
  if (!req.user || !req.user._id) {
    return res.status(401).json({ message: "Not authorized, user not found" });
  }
  const { productId } = req.body;
  if (!productId) {
    res.status(400);
    throw new Error("Missing productId in request body");
  }
  const user = await User.findById(req.user._id);
  
  if (!user.wishlist.some(item => item.productId && item.productId.toString() === productId.toString())) {
    
    const Product = require('../models/productModel');
    const product = await Product.findById(productId);
    if (!product) {
      res.status(404);
      throw new Error("Product not found");
    }
    user.wishlist.push({
      productId: product._id,
      name: product.name,
      price: Number(product.price), 
      category: product.category,
      seller: product.seller,
      stock: product.stock,
      image: product.images && product.images.length > 0 ? product.images[0].image : '',
      ratings: Number(product.ratings), 
      createdAt: new Date()
    });
    await user.save();
  }
  res.json({ wishlist: user.wishlist });
});

const deleteWishlistItem = asyncHandler(async (req, res) => {
  if (!req.user || !req.user._id) {
    return res.status(401).json({ message: "Not authorized, user not found" });
  }
  const { productId } = req.body;
  const user = await User.findById(req.user._id);
  user.wishlist = user.wishlist.filter(
    (item) => item.productId && item.productId.toString() !== productId.toString()
  );
  await user.save();
  res.json({ wishlist: user.wishlist });
});

const updateWishlist = asyncHandler(async (req, res) => {
  if (!req.user || !req.user._id) {
    return res.status(401).json({ message: "Not authorized, user not found" });
  }
  const { wishlistIndex, update } = req.body; 
  const user = await User.findById(req.user._id);
  if (user.wishlist[wishlistIndex]) {
    Object.assign(user.wishlist[wishlistIndex], update);
    await user.save();
    res.json({ success: true, wishlist: user.wishlist[wishlistIndex] });
  } else {
    res.status(404);
    throw new Error("Wishlist item not found");
  }
});

const getWishlists = asyncHandler(async (req, res) => {
  if (!req.user || !req.user._id) {
    return res.status(401).json({ message: "Not authorized, user not found" });
  }
  const user = await User.findById(req.user._id).populate("wishlist");
  res.json({ wishlist: user.wishlist });
});

const createWishlistItems = asyncHandler(async (req, res) => {
  if (!req.user || !req.user._id) {
    return res.status(401).json({ message: "Not authorized, user not found" });
  }
  const { productIds } = req.body;
  if (!Array.isArray(productIds) || productIds.length === 0) {
    res.status(400);
    throw new Error("Missing productIds array in request body");
  }
  const user = await User.findById(req.user._id);
  const Product = require('../models/productModel');
  for (const productId of productIds) {
    if (!user.wishlist.some(item => item.productId && item.productId.toString() === productId.toString())) {
      const product = await Product.findById(productId);
      if (product) {
        user.wishlist.push({
          productId: product._id,
          name: product.name,
          price: Number(product.price),
          category: product.category,
          seller: product.seller,
          stock: product.stock,
          image: product.images && product.images.length > 0 ? product.images[0].image : '',
          ratings: Number(product.ratings),
          createdAt: new Date()
        });
      }
    }
  }
  await user.save();
  res.json({ wishlist: user.wishlist });
});

const deleteWishlistItems = asyncHandler(async (req, res) => {
  if (!req.user || !req.user._id) {
    return res.status(401).json({ message: "Not authorized, user not found" });
  }
  const { productIds } = req.body;
  if (!Array.isArray(productIds) || productIds.length === 0) {
    res.status(400);
    throw new Error("Missing productIds array in request body");
  }
  const user = await User.findById(req.user._id);
  user.wishlist = user.wishlist.filter(
    (item) => !productIds.includes(item.productId?.toString())
  );
  await user.save();
  res.json({ wishlist: user.wishlist });
});

const updateWishlists = asyncHandler(async (req, res) => {
  if (!req.user || !req.user._id) {
    return res.status(401).json({ message: "Not authorized, user not found" });
  }
  const { updates } = req.body; 
  if (!Array.isArray(updates) || updates.length === 0) {
    res.status(400);
    throw new Error("Missing updates array in request body");
  }
  const user = await User.findById(req.user._id);
  for (const { productId, update } of updates) {
    const item = user.wishlist.find(item => item.productId && item.productId.toString() === productId.toString());
    if (item) {
      Object.assign(item, update);
    }
  }
  await user.save();
  res.json({ wishlist: user.wishlist });
});

const getReviews = asyncHandler(async (req, res) => {
  if (!req.user || !req.user._id) {
    return res.status(401).json({ message: "Not authorized, user not found" });
  }
  const user = await User.findById(req.user._id).populate("reviews.product");
  res.json({ reviews: user.reviews });
});

const addReview = asyncHandler(async (req, res) => {
  if (!req.user || !req.user._id) {
    return res.status(401).json({ message: "Not authorized, user not found" });
  }
  const { productId, rating, comment } = req.body;
  const user = await User.findById(req.user._id);
  user.reviews.push({ product: productId, rating, comment });
  await user.save();
  res.json({ reviews: user.reviews });
});

const deleteReview = asyncHandler(async (req, res) => {
  if (!req.user || !req.user._id) {
    return res.status(401).json({ message: "Not authorized, user not found" });
  }
  const { reviewId } = req.body;
  const user = await User.findById(req.user._id);
  user.reviews = user.reviews.filter(
    (r) => r._id.toString() !== reviewId.toString()
  );
  await user.save();
  res.json({ reviews: user.reviews });
});

const getOrders = asyncHandler(async (req, res) => {
  if (!req.user || !req.user._id) {
    return res.status(401).json({ message: "Not authorized, user not found" });
  }
  const user = await User.findById(req.user._id);
  res.json({ orders: user.orders });
});

const getOrderById = asyncHandler(async (req, res) => {
  if (!req.user || !req.user._id) {
    return res.status(401).json({ message: "Not authorized, user not found" });
  }
  const { orderId } = req.params;
  const user = await User.findById(req.user._id);
  
      const order = user.orders.find(order => 
      order._id.toString() === orderId || 
      (order.createdAt && order.createdAt.toISOString() === orderId)
    );
  
  if (order) {
    res.json({ success: true, order });
  } else {
    res.status(404).json({ success: false, message: "Order not found" });
  }
});

const createOrderSnapshot = asyncHandler(async (req, res) => {
  if (!req.user || !req.user._id) {
    return res.status(401).json({ message: "Not authorized, user not found" });
  }
  const { order } = req.body;
  
  const orderToSave = {
    ...order,
    shippingAddress: order.shippingAddress || null,
    paymentMethod: order.paymentMethod || null,
  };
  const user = await User.findById(req.user._id);
  user.orders.push(orderToSave);
  await user.save();
  const newOrder = user.orders[user.orders.length - 1];
  res.json({ success: true, order: newOrder, orders: user.orders });
});

const deleteOrderSnapshot = asyncHandler(async (req, res) => {
  if (!req.user || !req.user._id) {
    return res.status(401).json({ message: "Not authorized, user not found" });
  }
  const { createdAt } = req.body; 
  const user = await User.findById(req.user._id);
  const initialLength = user.orders.length;
  user.orders = user.orders.filter(order => order.createdAt && order.createdAt.toISOString() !== createdAt);
  if (user.orders.length === initialLength) {
    return res.status(404).json({ message: "Order not found" });
  }
  await user.save();
  res.json({ orders: user.orders });
});

const updateOrderSnapshot = asyncHandler(async (req, res) => {
  if (!req.user || !req.user._id) {
    return res.status(401).json({ message: "Not authorized, user not found" });
  }
  const { createdAt, update } = req.body; 
  const user = await User.findById(req.user._id);
  const order = user.orders.find(order => order.createdAt && order.createdAt.toISOString() === createdAt);
  if (order) {
    Object.assign(order, update);
    await user.save();
    res.json({ order, orders: user.orders });
  } else {
    res.status(404);
    throw new Error("Order not found in user history");
  }
});

const getCarts = asyncHandler(async (req, res) => {
  if (!req.user || !req.user._id) {
    return res.status(401).json({ message: "Not authorized, user not found" });
  }
  const user = await User.findById(req.user._id);
  res.json({ carts: user.carts });
});

const createCartSnapshot = asyncHandler(async (req, res) => {
  if (!req.user || !req.user._id) {
    return res.status(401).json({ message: "Not authorized, user not found" });
  }
  const { cart } = req.body;
  if (!cart || !Array.isArray(cart.cartItems) || cart.cartItems.length === 0) {
    res.status(400);
    throw new Error("Missing or invalid cart in request body");
  }
  
  for (const item of cart.cartItems) {
    if (!item.productId || typeof item.qty !== 'number') {
      res.status(400);
      throw new Error("Each cart item must have a productId and qty");
    }
  }
  const user = await User.findById(req.user._id);
  user.carts.push(cart);
  await user.save();
  res.json({ success: true, carts: user.carts });
});

const deleteCartSnapshot = asyncHandler(async (req, res) => {
  if (!req.user || !req.user._id) {
    return res.status(401).json({ message: "Not authorized, user not found" });
  }
  const { createdAt } = req.body; 
  const user = await User.findById(req.user._id);
  const initialLength = user.carts.length;
  user.carts = user.carts.filter(cart => cart.createdAt && cart.createdAt.toISOString() !== createdAt);
  if (user.carts.length === initialLength) {
    return res.status(404).json({ message: "Cart not found" });
  }
  await user.save();
  res.json({ carts: user.carts });
});

const updateCartSnapshot = asyncHandler(async (req, res) => {
  if (!req.user || !req.user._id) {
    return res.status(401).json({ message: "Not authorized, user not found" });
  }
  const { createdAt, update } = req.body; 
  const user = await User.findById(req.user._id);
  const cart = user.carts.find(cart => cart.createdAt && cart.createdAt.toISOString() === createdAt);
  if (cart) {
    Object.assign(cart, update);
    await user.save();
    res.json({ cart, carts: user.carts });
  } else {
    res.status(404);
    throw new Error("Cart not found in user history");
  }
});

module.exports = { createUser, login, logout, getProfile, updateProfile, getWishlist, createWishlistItem, deleteWishlistItem, updateWishlist, getWishlists, createWishlistItems, deleteWishlistItems, updateWishlists, getOrders, getOrderById, createOrderSnapshot, deleteOrderSnapshot, updateOrderSnapshot, getCarts, createCartSnapshot, deleteCartSnapshot, updateCartSnapshot, getReviews, addReview, deleteReview };