Imports Microsoft.VisualBasic
Imports System.Data
Imports System.Data.SqlClient
Imports System.Collections.Generic

''' <summary>
''' The layer between the shopping cart and the storage location of the cart
''' </summary>
''' <remarks>The cart is stored in the session. Unlike many shopping carts, choice of a Pizza is fairly
''' ephemeral, so doesn't need long-lived storage</remarks>
Public Class StoredShoppingCart

    ''' <summary>
    ''' Read the shopping cart from its storage location
    ''' </summary>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Shared Function Read() As ShoppingCart

        Return FetchCart()

    End Function

    ''' <summary>
    ''' Update the delivery charge of the cart
    ''' </summary>
    ''' <param name="DeliveryCharge"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Shared Function Update(ByVal DeliveryCharge As Decimal) As Integer

        Dim cart As ShoppingCart = FetchCart()

        cart.DeliveryCharge = DeliveryCharge

    End Function

#Region "Cart Items"

    ''' <summary>
    ''' Read the cart items from their storage location
    ''' </summary>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Shared Function ReadItems() As List(Of CartItem)

        Dim cart As ShoppingCart = FetchCart()

        Return cart.Items

    End Function

    ''' <summary>
    ''' Update the quantity required for the cart item
    ''' </summary>
    ''' <param name="MenuItemID"></param>
    ''' <param name="ItemSize"></param>
    ''' <param name="Quantity"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Shared Function UpdateItem(ByVal MenuItemID As Integer, ByVal ItemSize As String, ByVal Quantity As Integer) As Integer

        Dim cart As ShoppingCart = FetchCart()

        cart.Update(MenuItemID, ItemSize, Quantity)

    End Function

    ''' <summary>
    ''' Delete the cart item
    ''' </summary>
    ''' <param name="MenuItemID"></param>
    ''' <param name="ItemSize"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Shared Function DeleteItem(ByVal MenuItemID As Integer, ByVal ItemSize As String) As Integer

        Dim cart As ShoppingCart = FetchCart()

        cart.Delete(MenuItemID, ItemSize)

    End Function

    ''' <summary>
    ''' Insert an item into the cart
    ''' </summary>
    ''' <param name="MenuItemID"></param>
    ''' <param name="ItemName"></param>
    ''' <param name="ItemSize"></param>
    ''' <param name="Quantity"></param>
    ''' <param name="ItemPrice"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Shared Function InsertItem(ByVal MenuItemID As Integer, ByVal ItemName As String, ByVal ItemSize As String, ByVal Quantity As Integer, ByVal ItemPrice As Decimal) As Integer

        Dim cart As ShoppingCart = FetchCart()

        cart.Insert(MenuItemID, ItemSize, ItemName, ItemPrice, Quantity)

    End Function

#End Region

    ''' <summary>
    ''' Fetch the cart from it's storage location
    ''' </summary>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Private Shared Function FetchCart() As ShoppingCart

        ' Fetch the cart from the session
        Dim cart As ShoppingCart = DirectCast(HttpContext.Current.Session("Cart"), ShoppingCart)

        ' If it isn't in the session, then create a new cart
        ' and place it in the session
        If cart Is Nothing Then
            cart = New ShoppingCart()
            HttpContext.Current.Session("Cart") = cart
        End If

        Return cart

    End Function


End Class