A simple implementation of a Jokenpo server

jokenpo.rb

# Author: Rodrigo Chamun

# How to run:
#   Server: ruby jokenpo.rb
#   Players: $ nc server_address 6666 - 2>/dev/null

require 'socket'
require 'forwardable'

class Move
  attr_accessor :player, :verb

  def initialize(player, verb, inferior_move)
    @player = player
    @verb = verb
    @inferior_move = inferior_move
  end

  def >(move)
    move.class == @inferior_move
  end

  def win_sentence(loser)
    "#{self.class} #{verb} #{loser.class}. #{player} wins!"
  end
end

class Rock < Move
  def initialize(player)
    super(player, 'smashes', Scissors)
  end
end

class Scissors < Move
  def initialize(player)
    super(player, 'cuts', Paper)
  end
end

class Paper < Move
  def initialize(player)
    super(player, 'wraps', Rock)
  end
end

class Hulk < Move
  def initialize(player)
    super(player, 'smashes', nil)
  end
  
  def >(move)
    move.class != Hulk
  end

  def win_sentence(loser)
    "Hulk smashes! #{player} wins."
  end
end

class Broadcast
  def initialize(*connections)
    @connections = connections
  end

  def puts(message, *ignore)
    @connections.each do |c|
      c.puts message unless ignore.include?(c)
    end
  end

  def new_line
    puts("\n")
  end

  def <<(item)
    @connections << item
  end
end

class Player
  extend Forwardable
  def_delegators :@socket, :puts
  attr_accessor :name

  def initialize(name, socket)
    @name = name    
    @socket = socket
  end

  def get_move
    Object.const_get(@socket.gets.chomp.capitalize).new(name)
  end
end

class Game
  def self.start
    Game.new.start
  end

  def initialize
    @broadcast = Broadcast.new(STDOUT) 
    connection = TCPServer.new 6666

    @broadcast.puts 'Waiting for Player 1'

    @p1 = Player.new('Player 1', connection.accept)
    puts_welcome_message(@p1)
    @broadcast << @p1

    @broadcast.puts 'Waiting for Player 2 to connect'
    
    @p2 = Player.new('Player 2', connection.accept)
    puts_welcome_message(@p2)
    @broadcast << @p2
  end

  def start
    loop do
      m1 = get_player_move(@p1)
      m2 = get_player_move(@p2)

      begin
        winner, loser = eval_moves(m1, m2)
        @broadcast.puts winner.win_sentence(loser)
      rescue
        @broadcast.puts "Both played #{m1.class}. It's a draw!"
      end
      @broadcast.new_line
    end
  rescue Interrupt
    @broadcast.puts "Server shut down."
  end

  private

  def get_player_move(player)
    @broadcast.puts("Waiting for #{player.name} to play.", player)
    begin
      player.puts('You move!')
      move = player.get_move 
    rescue NameError
      player.puts("You can't play that!")
    end while move.nil? 
    move
  end

  def eval_moves(m1, m2)
    return [m1, m2] if m1 > m2
    return [m2, m1] if m2 > m1
    raise 'draw'
  end

  def puts_welcome_message(player)
    player.puts "Welcome to Jokenpo! You are #{player.name}"
    player.puts 'Valid moves are: rock, paper and scissors'
  end
end

Game.start