Ouroborian Constellomancer

The mana values of the top four cards of your
library are revealed.
{t}, Shuffle your library: Spells you cast this turn
cost {1}{u} less to cast. Activate this ability only if
the top four cards of your library have different
mana values.
{t}: Draw a card, then put a card from your hand
into your library fourth from the top.