Hi Gozdom and welcome to the guild
I'd love to tell you that there is a silver bullet that will do all that you ask. The nearest that I've come to it is software called 'City Generator' (google will take you to the site). But City Generator is expensive and it has high learning curve (knowing how to write code is very, very helpful). City Generator builds 3d models of cities for you.
There is the (free) RPG City Creator (do a search on this site). That has a lots of dials and knobs but it is much easier to use, but it will not produce individual roofs. You will have to draw those in yourself.
I'd be interested to see what others have to say, but I can't think of an easy way to do what you want.
All the best