Extended Shuffle

extended_shuffle

class Card
  attr_accessor :value, :suit

  def initialize(v, s)
    @value = v
    @suit = s
  end
end

class Deck
  def initialize
    suits = 'Clubs', 'Diamonds', 'Hearts', 'Spades'
    values = 'Ace', 2, 3, 4, 5, 6, 7, 8, 9, 10, 'Jack', 'Queen', 'King'

    @cards = suits.product(values)

    20.times { shuffle }
  end

  def shuffle
    riffle_shuffle
    over_hand_shuffle
    riffle_shuffle
    riffle_shuffle
    riffle_shuffle
    over_hand_shuffle
    cut
  end

  def cut    
    split_at = (((45..55).to_a.sample / 100.0) * @cards.count).to_i
    left_hand = @cards.shift(split_at)
    right_hand = @cards.shift(@cards.count)
    @cards += right_hand
    @cards += left_hand  
  end

  def over_hand_shuffle
    split_at = (((10..15).to_a.sample / 100.00) * @cards.count).to_i
    left_hand = @cards.shift(split_at)
    right_hand = @cards.shift(@cards.count)

    while right_hand.count > 0 
      left_hand.unshift(right_hand.shift([8,9,10,11,12,13,14,15].sample))
    end
    @cards += left_hand
  end

  def riffle_shuffle    
    split_at = (((40..60).to_a.sample / 100.0) * @cards.count).to_i # split the deck somewhere between 40% and 60%
    left_hand = @cards.shift(split_at)
    right_hand = @cards.shift(@cards.count)

    while left_hand.count > 0 || right_hand.count > 0
      if left_hand.count > 0
        case
        when left_hand.count >= 3
          @cards += left_hand.shift([1, 2, 3].sample)
        when left_hand.count == 2
          @cards += left_hand.shift([1, 2].sample)
        when left_hand.count == 1
          @cards += left_hand.shift(1)
        end
      end

      if right_hand.count > 0
        case
        when right_hand.count >= 3
          @cards += right_hand.shift([1, 2, 3].sample)
        when right_hand.count == 2
          @cards += right_hand.shift([1, 2].sample)
        when right_hand.count == 1
          @cards += right_hand.shift(1)
        end
      end
    end
  end
end

deck = Deck.new