Go into the scripts for the game and hit ctrl alt F and search for the abilities like tinted lense and adaptability. Those are kind of similar. Basically what they do is change the damage output of a move based on ability. So you can get a base from there. Then something you could do is specify every type of move and add a boosted damage output to it. So if the move type is normal, then the damage is boosted by X amount and so on for every type.
I'm sure there's an easier way to do it but that's how I would go about it. Sorry I can't be more specific now I'm not at home, but it's a good place to start building your script