When enemy gets to your reach, you can use AOO ... ?
In a sense. A ready action (melee version, at least) is basically an attack of opportunity that doesn't require for the enemy to "move wrong in your zone of control". Just to come in your range in any way, shape or form.
The way Solasta let you manage RA for casters is that they work only with attack cantrips (i.e. Firebolt or Eldritch Blast) on the other hand.
