How to make an idle detector on Mac os x?

Question

Objective-C

I want to write a program that will determine whether I am afk now or not.
How to do it? I understand that you need to monitor keystrokes and mouse movements. Will it load the processor? Maybe Macos is already generating the notification I need?

Answer 1

Maybe this will help? www.xs-labs.com/en/archives/articles/iokit-idle-time

Answer 2

How are screensavers arranged?
What latency (accuracy) do you need?