Any home improvement gurus here?

[Wapsie B]

I've got a problem with my upstairs bathroom. It seems there's a leak underneath the shower which is seeping onto the ceiling below, causing damage. How big of a job is it to remove the tub, fix the leak and whatever structural repairs? I'm assuming part of the flooring/ceiling would have to be replaced also. I know no one can give a hard and fast estimate on what it would cost without looking at it. But based on experience how expensive is a job like this?