Defensive Duelist (Rework)

When you are Wielding a weapon that uses your Dexterity modifier and hold nothing else in your other hand you can add your proficiency bonus to your total AC to any melee attack made against you.

Additionally, when a melee attack made against you hits, you can use your reaction to take half the total damage it deals. As part of the same reaction, if the target is within your reach, you may make a melee weapon attack against it, if you hit, it takes half of your weapon's damage type of the damage you took.
This effect can only be done once per long rest.