Cast only if

[jwan]

Hello (and sorry for my english).
Is there any addon or is it real to make one that track buff on character and only allow to re-cast buff skill if previous has already expired.
Maybe smth like addon "Only Cast Crystal Fragments Proc" (that check skillID on action bar and prevent cast if skill has basic form), but for check BuffID ?
upd1: what about debuffID check? if it is working it is possible to "Hit all 6 buttons and only 1 skill will be used because other casts will be prevented if buff or dot skill active.