CC:Tweaked Create Elevator screen

-- floor_pad.lua

local enderModem = peripheral.wrap("bottom")
local screen = peripheral.wrap("top")
local floor = 3
local isDocked = false
local currentFloorDocked = -1
local floors = {0, 1, 2, 3}

screen.setTextScale(0.5)

function requestElevatorStatus(floor)
    enderModem.open(10 + floor)
    enderModem.transmit(10 + floor, 10 + floor, "is_elevator_docked")
    local event, modemSide, receivedChannel, replyChannel, message, distance = os.pullEvent("modem_message")
    enderModem.close(10)
    if receivedChannel == 10 + floor and type(message) == "boolean" then
        return message
    else
        return false
    end
end

function updateStatus()
    while true do
        local localFloorDocked = -1

        for i = 0, 2 do
            local docked = requestElevatorStatus(i)
            if docked then
                localFloorDocked = i
                break
            end
        end

        isDocked = requestElevatorStatus(floor)
        currentFloorDocked = localFloorDocked

        sleep(1)
    end
end

function drawButton(background, textcolor, text, y)
    local screenWidth = screen.getSize()
    screen.setBackgroundColor(background)
    screen.setCursorPos(2, y)
    screen.write(string.rep(" ", screenWidth - 2))

    screen.setTextColor(textcolor)
    local textX = math.floor((screenWidth - #text) / 2) + 1
    screen.setCursorPos(textX, y)
    screen.write(text)
    screen.setBackgroundColor(colors.black)
    screen.setTextColor(colors.white)
end


function drawDisplay()
    while true do
        sleep(1)
        screen.clear()

        if not isDocked then
            screen.setTextScale(1)
            if currentFloorDocked == -1 then
                screen.setCursorPos(math.floor(screen.getSize() / 2) - 5, math.floor(screen.getSize() / 2))
                screen.write("In transit...")
            else
                screen.setCursorPos(math.floor(screen.getSize() / 2), math.floor(screen.getSize() / 2))
                screen.write("Call")
            end
        else
            screen.setTextScale(0.5)
            screen.setCursorPos(1,1)
            screen.clear()
            screen.setCursorPos(1,1)
            screen.setBackgroundColor(colors.green)
            screen.clearLine()
            screen.setCursorPos(math.floor(screen.getSize() / 2)-2, 1)
            screen.setTextColor(colors.white)
            screen.write("Floors")


            screen.setTextColor(colors.white)
            screen.setBackgroundColor(colors.black)
            for i, f in ipairs(floors) do
                drawButton(colors.white, colors.black, (i-1) .. "", 3 + f * 2)
            end
        end
    end
end

function listenForClicks()
    while true do
        local event, side, x, y = os.pullEvent("monitor_touch")

        if x == 1 and y == 1 then
            os.reboot()
        end

        if not isDocked then
            enderModem.transmit(10 + floor, 10 + floor, "elevator_request")
            os.sleep(0.5)
            os.reboot()
        else
            y = y - 3
            y = y / 2
            enderModem.transmit(10 + y, 10 + y, "elevator_request")
        end
    end
end

parallel.waitForAll(updateStatus, drawDisplay, listenForClicks)