Desktop Notifications for Mac

Hi there, I am from a small startup based out of Boston and Toronto called Rayku (@[login to view URL]). We're the eBay for on-demand tutoring. Currently, we're looking to get an urgent Mac application developed that would detect the online, away, or offline status of the user, as well as notify them in real time with a tailored message (a question), along with a link in the form of desktop notification (if they're online). A windows version is already finished, and we're looking to create a Mac duplicate. Please get in touch if this sounds interesting. Thanks! Donny