controller...

Hiya Im designing a ''movement'' system right now. Both the character and npc''s will use it. Basically it simply handels transformations and such. The camera class will simply be attached to the character entity and can be rotated and zoomed by the user, but follows the character model. Anyway, since im using the movement class for both npc and non npc''s, I think Ill need to make some sorta controller system so that ai and the user can both control whatever entity there attached to. I don''t want to over design the system, but right now im thinking that the controller class will have to be a base class for derived controller classes since each entity may/will have its own unique actions. This lead me to think that maybe the controller class can be but a small interface for the ai system... hmmm. Confusing, but fun If anyone can follow what im asking, can you please give some some advice, please ?? ~Jason