Current MP based stat changes

Hi Guys

Ok, so the in the game I am currently making you play as a single wizard, and the fights are all about mp manipulation. You start each fight with 50% of your max mp every time. Various skills and events in each battle will increase or decrease your current mp. As your mp increases, your matk, mdef and speed increase. And likewise as it decreases, those same skills will decrease.

To make it a bit easier to implement, you will always have a max mp of 200 (regardless of level, equipment, etc). So you always start on 100, and each 2 extra mp you get gives you a 1% boost to your stats. So max mp is 150% stats and 0 mp is 50% stats.

The maths to figure out your increases and decreases is fairly simple, but I am not sure how to put it in the game as the stat changes need to happen after each attack. Ideally I would be able to manipulate elemental affinity the same way.

Any help with this would be greatly appreciated.