[Closed] file timer

hi. Does anybody know of any script or plugin that times how long you work on any file
or maybe folder so that you can allow for incremental saves etc. It would be very usefull
for timing how long is spent on any job. It would be cool if it didnt include time spent
previewing / rendering maybe stops counting while mouse is inactive.
Just a thought, maybe there is something available similar if not would it be difficult
to script.