Morgana, Decieving Schemer

At the beginning of combat on your turn, each
player reveals the top card of their libary, then you
gain 4 life for each white card revealed this way,
draw a card for each blue card revealled this way and
add one mana of any color for each each green card revealled each way. Then, Morgana deals 3 damage
to each opponent who has a red card revealled this
way and each opponent mills 3 cards if he/her revealled a black card.
{t},{x}{u/b}{u/r}: You may cast a spell less than or equal to
X this tur