require 'osx/cocoa'

class Bowling < OSX::NSObject
  
  def initialize
    @rolls = []
  end
  
  def roll(score)
    @rolls << score
  end
  
  def score
    score = 0
    first_roll_in_frame = 0

    10.times do |index|
      if is_strike?(first_roll_in_frame)
        score += 10 + next_two_rolls_for_strike(first_roll_in_frame)
        first_roll_in_frame += 1
      elsif is_spare?(first_roll_in_frame)
        score += 10 + bonus_roll_for_spare(first_roll_in_frame)
        first_roll_in_frame += 2
      else
        score += next_two_rolls(first_roll_in_frame)
        first_roll_in_frame += 2
      end
    end
    
    return score
  end
  
  def frame
    first_roll_in_frame = 0
    10.times do |index|
      if is_strike?(first_roll_in_frame)
        first_roll_in_frame += 1
      else
        return index + 1 if @rolls[first_roll_in_frame].nil? or @rolls[first_roll_in_frame + 1].nil?
        first_roll_in_frame += 2
      end
    end
  end
  
  def is_spare?(index)
    return (@rolls[index].to_i + @rolls[index + 1].to_i == 10)
  end
  
  def is_strike?(index)
    return @rolls[index] == 10
  end
    
  private #################################################
  
  def next_two_rolls_for_strike(index)
    return @rolls[index + 1].to_i + @rolls[index + 2].to_i
  end
  
  def bonus_roll_for_spare(index)
    return @rolls[index + 2].to_i
  end
  
  def next_two_rolls(index)
    return @rolls[index].to_i + @rolls[index + 1].to_i
  end
end