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cards.rb

# TODO: Create InvalidCard, DuplicateCard & InvalidDeck exceptions

class Card
  # 11 - 14 represent Jack through Ace respectively
  VALUES = (2..14).to_a
  SUITS = [:spades, :clubs, :hearts, :diamonds]

  attr_reader :value, :suit

  def initialize value, suit
    ensure_valid value, suit
    @value = value
    @suit = suit
  end

  def to_s
    case @value
    when 11
      "Jack of " + suit_to_s
    when 12
      "Queen of " + suit_to_s
    when 13
      "King of " + suit_to_s
    when 14
      "Ace of " + suit_to_s
    else
      @value.to_s + " of " + suit_to_s
    end
  end

  def >(other_card)
    @value > other_card.value
  end

  def <(other_card)
    @value < other_card.value
  end

  def ==(other_card)
    @value == other_card.value
  end

  private
    def ensure_valid value, suit
      # TODO: raise InvalidCard
      raise TypeError unless VALUES.include?(value) && SUITS.include?(suit)
    end

    def suit_to_s
      @suit.to_s.capitalize
    end
end

# Monkeypatch to determine if an array consists of unique elements
class Array
  def uniq?
    self.length == self.uniq.length
  end
end

class Deck
  include Enumerable
  extend Forwardable

  def initialize cards=[]
    ensure_valid cards
    @cards = cards
  end

  def_delegator :@cards, :shift, :draw
  def_delegator :@cards, :shift, :deal_card
  def_delegator :@cards, :include?, :has_card?
  def_delegators :@cards, :first, :last, :select

  def each &block
    @cards.each &block
  end

  def shuffle
    Deck.new @cards.shuffle
  end

  def shuffle!
    @cards.shuffle!
    self
  end

  def << new_card
    Deck.new @cards << new_card
  end

  def self.full_deck
    all_cards = []
    Card::SUITS.each do |suit|
      Card::VALUES.each do |value|
        all_cards << Card.new(value, suit)
      end
    end
    Deck.new all_cards
  end

  private
    def ensure_valid cards
      raise TypeError unless cards.uniq? # TODO: raise DuplicateCard
      cards.each do |card|
        raise TypeError unless card.is_a?(Card) # TODO: raise InvalidDeck
      end
    end
end