using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace AdmissionsRepresentatives.Models
{
    public class ShoppingCart
    {
        string ShoppingCartId { get; set; }
        AdmissionsStoreEntities storeDB = new AdmissionsStoreEntities();
        public const string CartSessionKey = "CartId";

        public static ShoppingCart GetCart(HttpContextBase context)
        {
            var cart = new ShoppingCart();
            cart.ShoppingCartId = cart.GetCartId(context);
            return cart;
        }

        // Helper method to simplify shopping cart calls
        public static ShoppingCart GetCart(Controller controller)
        {
            return GetCart(controller.HttpContext);
        }

        public void AddToCart(Product product)
        {
            // Get the matching cart and product instances
            var cartItem = storeDB.Carts.SingleOrDefault(
                c => c.CartId == ShoppingCartId
                && c.ProductId == product.ProductId);

            if (cartItem == null)
            {
                // Create a new cart item if no cart item exists
                cartItem = new Cart
                {
                    ProductId = product.ProductId,
                    Product = product,
                    CartId = ShoppingCartId,
                    Count = 1,
                    DateCreated = DateTime.Now
                };

                storeDB.Carts.Add(cartItem);
            }
            else
            {
                // If the item does exist in the cart, then add one to the quantity.
                cartItem.Count++;
            }

            System.Diagnostics.Debug.WriteLine(cartItem.ProductId);
            // Save Changes
            storeDB.SaveChanges();

            System.Diagnostics.Debug.WriteLine(cartItem.ProductId);
        }

        public int RemoveFromCart(int id)
        {
            // Get the cart
            var cartItem = storeDB.Carts.Single(
                cart => cart.CartId == ShoppingCartId
                && cart.RecordId == id);

            int itemCount = 0;

            if (cartItem != null)
            {
                if (cartItem.Count > 1)
                {
                    cartItem.Count--;
                    itemCount = cartItem.Count;
                }
                else
                {
                    storeDB.Carts.Remove(cartItem);
                }

                //Save changes
                storeDB.SaveChanges();
            }

            return itemCount;
        }

        public void EmptyCart()
        {
            var cartItems = storeDB.Carts.Where(cart => cart.CartId == ShoppingCartId);

            foreach (var cartItem in cartItems)
            {
                storeDB.Carts.Remove(cartItem);
            }

            // Save changes
            storeDB.SaveChanges();
        }

        public List<Cart> GetCartItems()
        {
            return storeDB.Carts.Where(cart => cart.CartId == ShoppingCartId).ToList();
        }

        public int GetCount()
        {
            // Get the count of each item in the cart and sum them up
            int? count = (from cartItems in storeDB.Carts
                          where cartItems.CartId == ShoppingCartId
                          select (int?)cartItems.Count).Sum();

            // Return 0 if all entries are null
            return count ?? 0;
        }

        public int CreateOrder(Order order)
        {
            var cartItems = GetCartItems();

            // Iterate over the items in the car, adding the order details for each
            foreach (var item in cartItems)
            {
                var orderDetail = new OrderDetail
                {
                    ProductId = item.ProductId,
                    OrderId = order.OrderId,
                    Quantity = item.Count
                };

                storeDB.OrderDetails.Add(orderDetail);
            }

            storeDB.SaveChanges();
            EmptyCart();

            return order.OrderId;
        }

        public string GetCartId(HttpContextBase context)
        {
            if (context.Session[CartSessionKey] == null)
            {
                if (!string.IsNullOrWhiteSpace(context.User.Identity.Name))
                {
                    context.Session[CartSessionKey] = context.User.Identity.Name;
                }
                else
                {
                    Guid tempCartId = Guid.NewGuid();

                    context.Session[CartSessionKey] = tempCartId.ToString();
                }
            }
            return context.Session[CartSessionKey].ToString();
        }
    }
}