Vivi's Itemshop --> Weapon Modifyer --> Stats Modifyer

Wassup guys'

I am currently trying to create a modification of VIVI's itemshop to which the admin in adding another item to the itemshop would designate a power level of certain items. For example:

Entering the #2 for a sword would increase a persons ATTACK by 2.

Entering the #4 for a piece of armor would increase there Defense by 4.

And there would also be exceptions to enter for example:

Creating a Mage's Robe with a Defense of 2 and a Magic Defense of 5 would alter the character's stats accordingly.

SO i am trying but trying in vain to create 4 extra input fields into the itemshop then integrating them into the stats of each character.

The 4 input fields being:

*Weapon Attack against normal *Weapon attack against magic

*Armor Defend against normal *Armor Defend against Magic

But heres the kicker, people will obviously will and can have possibly more than 1 weapon or piece of armor. Getting the code to properly multiply and Divide the original stat so it doesnt multiply twice or three times is whats hard.. lol

Is there anyone brave enough to maybe help me out or take on this task themselves?

lol.. I didnt think so, jk