local monitor = peripheral.find("monitor")
local turtleStates = {}

-- Set monitor display
monitor.setTextScale(0.5)
monitor.clear()
monitor.setCursorPos(1,1)

-- Pretty print function
local function draw()
    monitor.clear()
    monitor.setCursorPos(1,1)
    monitor.write("Turtle Monitor")
    local row = 2
    for id, data in pairs(turtleStates) do
        monitor.setCursorPos(1, row)
        local age = os.clock() - data.time
        local status = (age > 10) and "offline" or data.status
        monitor.write(string.format("%s (ID %d): %s", data.label, id, status))
        row = row + 1
    end
end

-- Main loop
rednet.open("back")  -- or side where modem is
while true do
    local msg, proto
    local id, message, protocol = rednet.receive("turtle_status", 2)
    if id then
        local ok, data = pcall(textutils.unserialize, message)
        if ok and data and data.id then
            turtleStates[data.id] = data
        end
    end
    draw()
end