Rock paper scissors

rps.rb

Hand = Struct.new(:name, :trumps) do
  def beats?(other_hand); trumps.include?(other_hand.name); end
  def draw?(other_hand); name == other_hand.name; end
end

class Game
  def self.rock_paper_scissors
    new([Hand.new(:rock, [:scissors]), Hand.new(:scissors, [:paper]), Hand.new(:paper, [:rock])])
  end

  def self.rock_paper_scissors_lizards_spock
    new([Hand.new(:rock, [:scissors, :lizard]),
         Hand.new(:scissors, [:paper, :lizard]),
         Hand.new(:paper, [:rock, :spock]),
         Hand.new(:lizard, [:spock, :paper]),
         Hand.new(:spock, [:scissors, :rock])])
  end

  def initialize(hands)
    @hands = hands
  end

  def winner(hand_name)
    player_hand, ai_hand = @hands.find { |hand| hand.name == hand_name }, @hands.sample

    return "It's a draw" if player_hand.draw?(ai_hand)
    winner = player_hand.beats?(ai_hand) ? "player" : "ai"
    "Player #{player_hand.name} vs. Ai #{ai_hand.name}\nWinner is: #{winner}"
  end
end