gistfile1.rb

require 'test/unit'

class Frame
  attr_reader :rolls

  def initialize(first_roll)
    @rolls = [first_roll]
  end

  def << pins
    @rolls << pins
  end

  def score
    @rolls.inject(0) { |total,roll| total + roll }
  end

  def score_with_bonus(remaining_frames)
    s = score
    unless remaining_frames.empty?
      next_rolls = remaining_frames[0..1].map{|f| f.rolls }.flatten
      s += next_rolls[0].to_i if self.closed?
      s += next_rolls[1].to_i if self.strike?
    end
    s
  end

  def unclosed?
    @rolls.size == 1 && !strike?
  end

  def closed?
    score == 10
  end

  def strike?
    @rolls.first == 10
  end
end

class Game
  def initialize
    @frames = []
  end

  def roll pins
    if @frames.size == 10 || (!@frames.empty? && @frames.last.unclosed?)
      @frames.last << pins
    else
      @frames << Frame.new(pins)
    end
  end

  def score
    s = 0
    @frames.each_with_index do |frame,i|
      s += frame.score_with_bonus(@frames[(i+1)..-1])
    end
    s
  end
end

class GameTest < Test::Unit::TestCase

  def setup
    @g = Game.new
  end

  def test_gutter_game
    rolls 20.gutters
    # roll_many(20,0)
    assert_equal 0, @g.score
  end

  def test_all_ones
    rolls '1'*20
    assert_equal 20, @g.score
  end

  def test_one_spare
    rolls '553' + 17.gutters
    assert_equal 16, @g.score
  end

  def test_one_strike
    rolls 'x34' + 16.gutters
    assert_equal 24, @g.score
  end

  def test_almost_perfect
    rolls 'x'*10+'00'
    assert_equal 270, @g.score
  end

  def test_perfect
    rolls 'x'*12
    assert_equal 300, @g.score
  end

  def test_crazy_normal_game
    rolls 'x |5/|3-|4/|x |24|81|x |x |1/3'
    assert_equal 141, @g.score
  end

  def test_rolls
    assert_equal 'x5532', numerify_rolls('x|5/|32')
  end

  def rolls string
    numerify_rolls(string).each_char do |c|
      @g.roll c.to_i
    end
  end

  def numerify_rolls string
    string.gsub(/[|\s]/,'').gsub(/(\d)\//){"#{$1}#{10-$1.to_i}"}
  end

end

class String
  alias :normal_to_i :to_i
  def to_i
    self == 'x' ? 10 : normal_to_i
  end
end

class Fixnum
  def gutters
    '0' * self
  end
end