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

-- Try to open modem on any side
local modemOpened = false
for _, side in ipairs({"top", "bottom", "left", "right", "front", "back"}) do
    if peripheral.getType(side) == "modem" then
        rednet.open(side)
        modemOpened = true
        break
    end
end

if not modemOpened then
    print("No modem found. Cannot continue.")
    return
end

if monitor then
    monitor.setTextScale(0.5)
    monitor.clear()
end

-- Logging function
local function logToFile(line)
    local file = fs.open(logFileName, "a")
    file.writeLine(("[%s] %s"):format(os.date("%H:%M:%S"), line))
    file.close()
end

-- Draws to monitor or terminal
local function draw()
    local output = {}

    table.insert(output, "Turtle Monitor")
    for id, data in pairs(turtleStates) do
        local age = os.clock() - data.time
        local status = (age > 10) and "offline" or data.status
        local line = string.format("%s (ID %d): %s - %d", data.label, id, status, age)
        table.insert(output, line)
    end

    -- Output to monitor if present
    if monitor then
        monitor.clear()
        monitor.setCursorPos(1,1)
        for i, line in ipairs(output) do
            monitor.setCursorPos(1, i)
            monitor.write(line)
        end
    else
        term.clear()
        term.setCursorPos(1,1)
        for _, line in ipairs(output) do
            print(line)
        end
    end
end

-- Main loop
while true do
    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
            logToFile(string.format("Received from %s (ID %d): %s", data.label, data.id, data.status))
        end
    end
    draw()
end