Preparation Macro?Follow

Simple question: Would it be possible to create macros for abilities such as Vanish and Evasion where you click it... and first it checks to see if the ability is on cooldown. If not, it does the action, but if it is on cooldown, it casts Prep?

Ex. I want to use Vanish. I hit the macro when Vanish is not on cooldown; I vanish. I hit it again when there is 3 min. left in the cooldown; Prep is cast. I hit it again; I vanish.

Would this be possible, and if yes, can someone write it out for me, I'm terrible with teh macroz. Thanks for any replies.

I'm not much of a macro guy, but you should try WoW forums. They have forums dedicated to it... just c & p it. May even have an addon for it.