It may seem like a simple question, but how do I put a p-trap in here without making it into an s-trap?

It's a room addition which required a new slab and footing to be poured. I think the rough-in drain line should have been installed in the wall cavity and not in front of it. In this picture, the sink is on the left, which will have the vent, with the toilet in the middle and the problem bathtub drain on the right.

Any suggestions?