Always listening digital assistant for the raspberry pi (or any ubuntu based os)

code and develop an always listening digital assistant for the raspberry pi (im guessing this might best be done as a raspbian app) so it can interface with a usb webcam and mic. it should be able to communicate with wolfram and input and read out mathematical problems. also schedule appointments with google calendar and read out the news headlines and conduct google searches. also play music on request by album, artist or genre from the library. the final app will be open source to unfortunately the budget is rather low.