Notes

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

namespace _Electronix.Models
{
public class ShoppingCart
{
NorthwindEntities db = new NorthwindEntities();
private string ShoppingCartId { get; set; }

public const string CartSessionKey = "CartId";

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

public static ShoppingCart GetCart(Controller controller)
{
return GetCart(controller.HttpContext);
}

public string GetCartId(HttpContextBase context)
{
if (context.Session[CartSessionKey] == null)
{
if (!String.IsNullOrEmpty(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();
}

public void AddToCart(Product product)
{
var cartItem = db.Carts.SingleOrDefault(c => c.CartId == ShoppingCartId && c.ProductId == product.ProductID);
if (cartItem == null)
{
cartItem = new Cart
{
ProductId = product.ProductID,
CartId = ShoppingCartId,
Count = 1,
DateCreated = DateTime.Now
};
db.Carts.Add(cartItem);
}
else
{
cartItem.Count++;
}
db.SaveChanges();
}

public int RemoveItem(int id)
{
var cartItem = db.Carts.Single(cart => cart.CartId == ShoppingCartId && cart.RecordId == id);
int itemCount = 0;
if (cartItem != null)
{
if (cartItem.Count > 1)
{
cartItem.Count--;
itemCount = (int)cartItem.Count;
}
else
{
db.Carts.Remove(cartItem);
}
db.SaveChanges();
}
return itemCount;
}

public void EmptyCart()
{
var cartItems = db.Carts.Where(cart => cart.CartId == ShoppingCartId);
foreach (var item in cartItems)
{
db.Carts.Remove(item);
}
db.SaveChanges();
}

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

public int GetCount()
{
int? count = (from cartItems in db.Carts
where cartItems.CartId == ShoppingCartId
select (int?)cartItems.Count).Sum();
return count ?? 0;
}

public decimal GetTotal()
{
decimal? total = (from cartItems in db.Carts
where cartItems.CartId == ShoppingCartId
select (int?)cartItems.Count * cartItems.Product.UnitPrice).Sum();
return total ?? decimal.Zero;
}

public int CreateOrder(Order order)
{
decimal orderTotal = 0;
var cartItems = GetCartItems();
foreach (var item in cartItems)
{
var orderDetail = new OrderDetail
{
OrderID=order.OrderID,
ProductID=(int)item.ProductId,
Quantity = (short)item.Count,
UnitPrice = (int)item.Product.UnitPrice
};
orderTotal += ((int)item.Count * (decimal)item.Product.UnitPrice);
db.OrderDetails.Add(orderDetail);
}

order.Total = orderTotal;
db.SaveChanges();
EmptyCart();
return order.OrderID;
}

public void MigrateCart(string userName)
{
var shoppinCart = db.Carts.Where(c => c.CartId == ShoppingCartId);
foreach (Cart item in shoppinCart)
{
item.CartId = userName;
}
db.SaveChanges();
}
}
}