class Deck

  include Enumerable

  attr_reader :cards

  RANKS = [*2..10, 'Jack', 'Queen', 'King', 'Ace']
  SUITS = %w{ Clubs Diamonds Hearts Spades }

  # initialize a deck of cards using the RANKS and SUITS constants
  def initialize
    @cards = []

    RANKS.product(SUITS).each do |rank, suit|
      @cards << Card.new(rank, suit)
    end
  end

  # shuffle the deck
  def shuffle!
    @cards.shuffle!
  end

  # draw a card from the deck
  def draw
    @cards.shift
  end

  # determines if the deck is empty
  def empty?
    @cards.empty?
  end

  # Enumerable#each
  def each(&block)
    @cards.each do |card|
      if block_given?
        block.call card
      else
        yield card
      end
    end
  end

end