elevator lobby display

local modem = peripheral.find("modem")
local monitor = peripheral.find("monitor")
local speaker = peripheral.find("speaker")

monitor.setTextScale(1)
monitor.setTextColour(colours.green)

local configFileName = "lobby_display_config.txt"
local computerID = os.getComputerID()
local config = {channel = "", currentFloor = "", computerID = ""}

local elevatorFloor = 0
local prevFloor = 0

-- Save Config to file
local function saveConfig(config)
  local configData = textutils.serializeJSON(config)
  local file = fs.open(configFileName, "w")
  file.write(configData)
  file.close()
end

-- Load Config from file
local function loadConfig()
  if fs.exists(configFileName) then
    local file = fs.open(configFileName, "r")
    local configData = file.readAll()
    file.close()
    config = textutils.unserializeJSON(configData)
  end
end

local function refreshMonitor()
  monitor.clear()
  monitor.setCursorPos(1, 1)
end

local function animateFloorChange(newFloor)
  local width, height = monitor.getSize()
  local x = math.ceil(width / 2)
  local startY, endY

  if newFloor > prevFloor then

    startY = height
    endY = math.ceil(height / 2)
  else
    startY = 1
    endY = math.ceil(height / 2)
  end

  for y = startY, endY, newFloor > prevFloor and -1 or 1 do
    refreshMonitor()
    monitor.setCursorPos(x, y)
    monitor.write(tostring(newFloor))
    sleep(0.1)
  end

  prevFloor = newFloor
end

local function mainLoop(config)
  modem.open(tonumber(config.channel))
  while true do
    local event, modem, senderChannel, replyChannel, message, senderDistance = os.pullEvent()
    if event == "modem_message" and senderChannel == tonumber(config.channel) then  -- Use config.channel here
      if string.sub(message, 1, 5) == "idle:" then
        elevatorFloor = tonumber(string.sub(message, 6))
        animateFloorChange(elevatorFloor)
        print("Elevator floor: " .. elevatorFloor)
        if elevatorFloor == tonumber(config.currentFloor) then  -- Use config.currentFloor here
          if prevFloor ~= elevatorFloor then
            speaker.playSound("minecraft:block.note_block.pling")
          else
            speaker.playSound("minecraft:block.note_block.bell", 0.5, 0.3)
          end
        end
      end
    end
  end
end

-- Initialization
local function initializeClient()
  loadConfig()
  if not config.channel or config.channel == "" then
    print("Please enter the channel to use:")
    config.channel = tonumber(read())
  end
  if not config.currentFloor or config.currentFloor == "" then
    print("Please enter the current floor:")
    config.currentFloor = tonumber(read())
  end
  if not config.computerID then
    config.computerID = tostring(computerID)  -- Convert to string if needed
  end
  saveConfig(config)
  mainLoop(config)
end

-- Entry Point
initializeClient()