Option Strict On
Public Class Form1

    Private Sub btnCalc_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalc.Click
        Dim SpoolsOrdered As Integer
        Dim SpoolsInStock As Integer
        Dim ReadyToShip As Integer
        Dim BackOrder As Integer
        Dim SpoolsCost As Integer

        Dim Shipping As Decimal
        Dim TotalCost As Decimal


        SpoolsInStock = getInStock()
        SpoolsOrdered = CInt(txtNumSpools.Text)
        If SpoolsOrdered < SpoolsInStock Then
            SpoolsCost = SpoolsOrdered * 100
        Else
            SpoolsCost = SpoolsInStock * 100
        End If
        ReadyToShip = CalcReadyToShip(SpoolsInStock, SpoolsOrdered)

        TotalCost = ShippingCharges(ReadyToShip) + SpoolsCost

        lblSpoolsReadyOut.Text = ReadyToShip.ToString()
        BackOrder = BackOrdered(SpoolsInStock, SpoolsOrdered)
        lblSpoolsBackOrderOut.Text = BackOrder.ToString()
        Shipping = ShippingCharges(ReadyToShip)
        lblShipHandleOut.Text = Shipping.ToString("c")
        lblTotalOut.Text = TotalCost.ToString("c")
    End Sub

    Function getInStock() As Integer
        Dim Input As String
        Dim SpoolsInStock As Integer

        Input = InputBox("Enter number of spools that are in stock")
        SpoolsInStock = CInt(Input)

        Return SpoolsInStock
    End Function

    Function CalcReadyToShip(ByVal SpoolsInStock As Integer, ByVal SpoolsOrdered As Integer) As Integer
        Dim NumReadyToShip As Integer
        If SpoolsOrdered <= SpoolsInStock Then
            NumReadyToShip = SpoolsOrdered
        Else
            NumReadyToShip = SpoolsInStock
        End If
        Return NumReadyToShip
    End Function

    Function BackOrdered(ByVal SpoolsInStock As Integer, ByVal SpoolsOrdered As Integer) As Integer
        Dim NumBackOrdered As Integer

        If SpoolsInStock >= SpoolsOrdered Then
            NumBackOrdered = 0
        Else
            NumBackOrdered = SpoolsOrdered - SpoolsInStock
        End If
        Return NumBackOrdered
    End Function

    Function ShippingCharges(ByVal ReadyToShip As Integer) As Decimal
        Dim Shipping As Decimal
        If chkRush.Checked Then
            Shipping = 15D * CDec(ReadyToShip)
        Else
            Shipping = 10D * CDec(ReadyToShip)
        End If
        Return Shipping
    End Function

    Private Sub btnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClear.Click
        resetSpools()
        resetDelivery()
    End Sub
    Private Sub resetSpools()
        txtNumSpools.Text = String.Empty
        chkRush.Checked = False
        txtNumSpools.Focus()
    End Sub
    Private Sub resetDelivery()
        lblSpoolsReadyOut.Text = String.Empty
        lblShipHandleOut.Text = String.Empty
        lblSpoolsBackOrderOut.Text = String.Empty
        lblTotalOut.Text = String.Empty
    End Sub

    Private Sub btnExit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnExit.Click
        Me.Close()
    End Sub
End Class