receiver.lua

-- Adjust as needed for your setup:

    -- Modem
    local modemSide = "top"
    -- Current Floor Header (used in multiline displays only)
    local multiH = "Current Floor"
    -- Moving Text (Used when elevator is moving between floors on name displays)
        -- Multiline config
        local moveL1 = "Elevator is"  -- Line 1
        local moveL2 = "moving"  -- Line 2
        -- Single Line config
        local moveSL = "Moving"


--Code starts here
local configFileName = "displays.txt"

function loadConfig()
    if fs.exists(configFileName) then
        local file = fs.open(configFileName, "r")
        local config = textutils.unserialize(file.readAll())
        file.close()
        return config
    else
        error("Configuration file not found. Please run the setup script first.")
    end
end

local config = loadConfig()

-- Prepare a table to hold the last displayed text for each display to minimize updates
local lastDisplayedText = {}


rednet.open(modemSide)

function centerText(text, line)
    local width, height = term.getSize()
    term.setCursorPos((width - string.len(text)) / 2, line)
    print(text)
end

function displayUI()
    term.clear()
    centerText("Controlling Displays", 1)
    centerText("Current Floor", 4)
end


function clearAndUpdateDisplay(display, text, displayId)
    if lastDisplayedText[displayId] ~= text then
        display.clear()
        display.setCursorPos(1, 1)
        display.write(text)
        display.update()
        lastDisplayedText[displayId] = text
    end
end

function updateDisplays(floor)
    for i, dispConfig in ipairs(config.displays) do
        local display = peripheral.wrap(dispConfig.side)
        if display then
            local displayText = dispConfig.type == "name" and floor.name or floor.num
            local h, w = display.getSize()
            local DispType = GetDispType(h, w)
            centerText(floor.num .. " - " .. floor.name, 6)

            if dispConfig.type == "name" then
                if DispType == "multi" then
                    if floor.num == "--" then
                        centerTextAndUpdate(display, moveL1, i, 1)
                        centerTextAndUpdate(display, moveL2, i, 2)
                    else
                        centerTextAndUpdate(display, multiH, i, 1)
                        centerTextAndUpdate(display, displayText, i, 2)
                    end
                    lastDisplayedText[i] = displayText
                else
                    if floor.num == "--" then
                        centerTextAndUpdate(display, moveSL, i, 1)
                    else
                        centerTextAndUpdate(display, displayText, i, 1)
                    end
                    lastDisplayedText[i] = displayText
                end
            else
                clearAndUpdateDisplay(display, displayText, i, 1)
            end
        else
            print("Display not found on side: " .. dispConfig.side)
        end
    end
end

function centerTextAndUpdate(display, text, displayId, line)
    if lastDisplayedText[displayId] ~= text then
        local h, w = display.getSize()
        display.setCursorPos(((w - string.len(text)) / 2) + 1, line)
        display.clearLine()
        display.write(text)
        display.update()
    end
end

function GetDispType(disph, dispw)
    local dtype = ""
    if disph == 1 then
        dtype = "single"
    else
        dtype = "multi"
    end
    return dtype
end

displayUI()

while true do
    local senderId, message, protocol = rednet.receive("ElevatorFloor")
    if protocol == "ElevatorFloor" then
        updateDisplays(message)
    end
end