Dance of the War Magi

The caster uses their deep knowledge of war magic to enhance their senses and reflexes making the world around them seem to slow to a crawl. 
While Dance of the War Magi is in effect, the caster has advantage on all attack rolls and may add either their dexterity or Inteligence bonus to their AC. 

if cast at a higher level the spell lasts for a number of rounds equal to the level of spell slot used.