Audio Switcher involving Optical and Stereo In, 5.1 Out

[hsadan]

I'm thinking of making an audio switcher that can switch between using an optical input or a stereo input.

The optical input would be coming from my PC, and can alternatively be analog 5.1 instead.

It would output analog 5.1 in order to connect to my speaker system. Preferably, a DSP chip that would do something with the stereo input to make it 5.1 would be nice.

What components would I need?

I'm very new to this, so would appreciate someone pointing me in the correct direction I have minor experience using microcontrollers, so that is an option if needed.