Custom mana cost questions

[Josemite]

I'm wondering if it's possible to either cancel a spell that is currently being cast or to reset the cooldown for one particular ability (or, for that matter, dynamically add a cooldown to an ability i.e. have a 0 second base cooldown and then later add an 8 second cooldown onto the ability if the spell is cast successfully). Or if anyone knows a decent way to do mana costs based on character level/max mana rather than built into the ability.

 

[chenlimin]

triggers, the action should be set cooldown and set unit's mana to whatever