Mastermind

mastermind.rb

class Code
  attr_reader :pegs
  def initialize
    @pegs = random
  end
  
  def random
    colors = ["R", "G", "B", "Y", "O", "P"]
    [colors[rand(6)], colors[rand(6)], colors[rand(6)], colors[rand(6)]].join
  end 
  
  def parse(input)
    input = input.split("")
    [exact_match(input), near_match(input)]
  end 
  
  def exact_match(input)
    exact_count = 0
    pegs_array = pegs.dup.split("")
    pegs_array.each_index do |i|
      exact_count += 1 if pegs[i] == input[i]
    end 
    exact_count
  end
  
  def near_match(input) 
    pegs_array = pegs.dup.split("")
    near_count = 0
    pegs.split("").each_index do |i|
      pegs_array[i] = nil if pegs[i] == input[i]
    end
    input.each_index do |i|
      if pegs_array.include?(input[i])
        near_count += 1 
        item = pegs_array.index(input[i])
        pegs_array[item] = nil
      end 
    end 
    near_count
  end 
end

class Game
  attr_reader :new_code, :secret_code, :last_input
  
  def rules
    puts "
    There are six different peg colors:
    * Red
    * Green
    * Blue
    * Yellow
    * Orange
    * Purple
  
    1. The computer selects a random code of four pegs.
    2. The player gets ten turns to guess the code.
    2. The player inputs their guess like so: 
      \"RGBY\" for red-green-blue-yellow.
    3. The computer tells the player how many exact matches 
       (right color in right spot) and near matches (right 
       color, wrong spot) the player guessed.
    4. The game ends when the player guesses the code, or 
       is out of turns.\n\n"
  end
  
  def initialize
    @turns = 10
    @new_code = Code.new
    @secret_code = @new_code.pegs
    @last_input = ""
  end 
  
  def turns
    @turns
  end 
  
  def round 
    puts "Welcome to Mastermind!"
    puts "Would you like to see the rules? (yes or no)"
    answer = gets.chomp
    rules if answer == "yes"
    puts "Press enter to play:"
    gets
    puts "Computer has thought of a sequence."
    
    while last_input != secret_code && turns > 0
      puts "Last chance!" if turns == 1
      puts "Make a guess:"
      @last_input = gets.chomp.upcase
      result = new_code.parse(last_input)
      puts "Exact matches: #{result[0]}, Near matches: #{result[1]}"
      @turns -= 1
    end
    
    if turns == 0 && last_input != secret_code
      puts "You lost. The sequence was #{secret_code}."
    else
      puts "You won with #{turns} turns to go!"
    end
  end
end


if __FILE__ == $PROGRAM_NAME
  game = Game.new
  game.round
end