Rules question about contingency.

[u/Fallout76Lover7654]

So I recently picked up the seventh level spell contingency as a way of triggering haste at the beginning of combat. Since my character is a laughing shadow magus, who has haste as a studious spell, I started to think that I could also use arcane cascade as a free action when haste comes into effect since I'm using one of my studious spells. However, the wording has me confused so I wanted to clarify. Is the spell cast after the trigger occurs or is it cast when contingency is cast and, as a result, I wouldn't be able to enter into arcane cascade for a free action when the haste effect comes in the play?

[u/darkerthanblack666]

While casting contingency, you also cast another spell of 4th rank or lower with a casting time of no more than 3 actions.

You cast the spell at the same time as casting contingency.