In a defense i am not used

I consider a strange defense the ones that i am not familiar with, and there are many, in this game my oponnent played Philidor Defense, i had played this one very few times and i don't know the lines of it. I usually get to italian game or spanish game (Ruy López).

But in this ocation my oponent made a totally unexpected move, nad that give me the oportunity to start an attack very early in the game.

So here is it: