cashRegister

os.pullEvent = os.pullEventRaw
checkoutcomputer = 32
alogin = "adminpassword"

function connect()
    rednet.open("bottom")
end

success = pcall(connect)
if not success then
    os.reboot()
end

monitor = peripheral.wrap("top")
if not monitor then
    os.reboot()
end

function displayBalance(balance)
    monitor.clear()
    monitor.setCursorPos(1, 2)
    monitor.write("Welcome!")
    monitor.setCursorPos(1, 4)
    monitor.write("$" .. balance)
end

function checkOut(balance)
    success = false
    while success ~= "true" do
        rednet.send(checkoutcomputer, balance)
        id, success = rednet.receive()
    end
    print("SUCCESS!")
end

function evaluateFormula(formula)
    -- Load the formula as a Lua function
    local func, err = load("return " .. formula)

    -- Check if there was an error compiling the formula
    if not func then
        return nil, "Invalid formula: " .. err
    end

    -- Execute the function and return the result
    local success, result = pcall(func)
    if success then
        return result
    else
        return nil, "Error evaluating formula: " .. result
    end
end

balance = 0
displayBalance(balance)

while true do
    print("type end to confirm order \n")
    print("Current Order: $" .. balance)
    input = io.read()
    if input == alogin then
        os.exit(1)
    end
    if input == "end" then
        checkOut(balance)
        break
    end
    if input ~= 0 then
        change = evaluateFormula(input)
        if change then
            balance = balance + change
        end
        displayBalance(balance)
    end
end
monitor.clear()
monitor.setCursorPos(1, 2)
monitor.write("Thank")
monitor.setCursorPos(1, 4)
monitor.write("You!")
os.sleep(5)
displayBalance(0)