Credit Card Reading Cashregister Mk 1 SCS3

--this program deals with Cash Transfers, as sort of a Cash Register, or a Card Swipe, WIP
Settings_AccountID = "Guest"
Settings_PaymentMode = 0--0= Set Price, 1 = Choose item, 2 = Quanity of Item
Settings_AdminCode = 0000
Settings_Prices = [1,1,1,1,1]--prices for sold items
Settings_Products = ["item","item","item","item","item"]
Settings_CashRegisterState = "Closed"--Open or closed, closed will prevent any Use from Customers.
--Sells
Temp_Items = nil
Temp_Total = 0
Temp_CustomerAccount = nil
local monitor = peripheral.find("monitor")
start()
function start()
    term.clear()
    Display("State")
    if Settings_CashRegiserState == "Open" then
        Standby()
    else
        print("this Register is Currently Closed")
    end
end

function Standby()
    term.clear()
    print("Please Wait for Cashier")
    local event, key = os.pullEvent("key")
    while true do
        Display("Total")
        if key == keys.1 then
            TempTotal = TempTotal + Settings_Prices[0]
        else if key == keys.2 && Settings_PaymentMode == 1 && Settings_Prices[1] != nil then
            TempTotal = TempTotal + Settings_Prices[1]
        else if key == keys.3 && Settings_PaymentMode == 1 && Settings_Prices[2] != nil then
            TempTotal = TempTotal + Settings_Prices[2]
        else if key == keys.4 && Settings_PaymentMode == 1 && Settings_Prices[3] != nil then
            TempTotal = TempTotal + Settings_Prices[3]
        else if key == keys.5 && Settings_PaymentMode == 1 && Settings_Prices[4] != nil then
            TempTotal = TempTotal + Settings_Prices[4]
        else if key == keys.enter then
            break
            sleep(20)
            CreditReader()
        end
    end
end

function CreditReader()
    print("Waiting for Customer to Insert Credit Card")
    Display("Write","Insert Card")
    while true do

    end
end

function Display(Action,Text)
    if Action == "Write" then
        monitor.setCursorPos(1,1)
        monitor.write(Text)
    else if Action == "Clear" then
        monitor.clear()
    else if Action == "Total" then
        monitor.setCursorPos(1,1)
        monitor.write(Temp_Total)
    else if Action == "State" then
        monitor.clear()
        monitor.setCursorPos(1,1)
        if Settings_CashRegisterState == "Open" then
            monitor.write("REGISTER IS OPEN")
        else if Settings_CashRegisterState == "Closed" then
            monitor.write("THIS REGISTER IS CLOSED")
        end
    end
end

function PaymentHandler()

end

function ErrorHandler()

end