Contingency condition: "If I am damaged by fire."
Companion spell: protection from energy (fire), caster level 11 (11x12=132 points of fire protection).
I know I could have said "If I am exposed to fire", or some other wording, but for the sake of this argument, consider the above condition.
If I am hit by a fire attack for 150 points of damage, do I take 1 point of fire damage and then the contingency triggers the protection from energy (fire) "immediately", in which case I would then only take an additional (149-132=) 17 points of fire damage?
Or would the contingency not be able to react until I've taken the full damage of the spell (150 points of fire damage) and then trigger--likely after I'm dead?
Per your own trigger you must first be hurt. Only in a couple places is damage minced up point by point. Otherwise, it's all nothing if you lack pre-existing resistance, protection, etc. One you have protection/absorption and so forth that's different. But per your post I'd say you take all 150 points of fire damage then your contingency would take effect as you don't have the benefit of protection from energy until after that point.
Since you specifically worded as "damaged" by fire then you take the 150 points damage, then contingency kicks in. If you had said "I am in danger of being damaged by fire" then it would have kicked in before damage occurs. Since the fire attack doesn't hit you with 150 points of damage over time, rather it hits you all at one
Also note that the spell that is triggered bycontingency can be no higher than 1/3 your caster level rounded down, with a maximum of 6th level. So I'm assuming you are level 11 and protection from energy is 3rd level...you should be good on that respect.
**EDIT**
Ninja'ed! That's what I get for not pressing submit until AFTER my meeting!
Or you could say "just prior to being hit with an attack that does fire damage."
Some GMs treat contingency triggers like genies do wishes. The "I am in danger of" could be twisted to mean many things.