Suggestions on a good way to get angle?

[mkaa00x]

Hey guys! we need a somewhat powerful motor than can also calculate angle, we want this motor to be able to turn all the time and for infinite rotations in either direction, (so kinda like a Mini CIM or maybe even a CIM although it can measure angle of it's rotation [0-360degress])

I'm not good at all with this sort of stuff, as in I'm not good with parts but once I know how they work I'll program them anytime. soooooo like is it possible to use a servo? is it turn-able over and over or how would we use some sort of encoder to calculate angle? helps please