Just you know, don’t go into “I’ll use modules because someone said it’s cool” mode. Make sure you understand why certain classes are in a seperate module before you do it.
As to notify: since you are triggering “attack” flipbook I guess you know that you are in “attacking” state. So if you collide with enemy check whether you are in “attacking” state at the moment and then you know you are damaging them. And of course it’d be better if you have a “Damagable” interface which enemies implement and you just call “damage” function on that interface ;).