How to perform this very specific visual check in code?

I’ll not be too verbose about this problem (no need for any code examples really).

So I have a problem with a UV-feature that I’m currently working on. I’ve managed to narrow down the issue to the bone and it all comes down to just performing a very simple visual check - a check that is very easy for a human eye to do but maybe not as easy to do in code with logic.

Is it possible to check if the face is to the left or to the right without doing a lot of selection operations (select/deselect/convert, etc)?? Creating the vector between the two points (v1) and the two perpendicular vectors (v2 and v3) is easy - just get the coordinates of these two points. But then the question is: Is it v2 or v3 that crosses over the face?