Write some Software for windows and Linux

I need a software to track working time of my staffs, this application should work on windows as well as on Linux. *It should follow a server client architecture. Server will run on admin system and the client will run on the employee systems. *Detect inactive desktop and log out automatically. *We should be able to use its api to extract data from this software to use that elseware. * It should be capable of capturing the screen.