Contents

module BookKeeping
  VERSION = 2
end

class Game
  PINS = { MIN: 0, MAX: 10 }.freeze
  at_exit { public :roll, :score }

  private

  def initialize
    @score_card = Hash.new { |frame_number, k| frame_number[k] = [] }
    @score_card[1]
  end

  def roll(pins)
    validate(pins)
    @score_card[current_frame] << pins
    @score_card[current_frame + 1] unless last_frame? || !frame_complete?
  end

  def validate(pins)
    raise StandardError, 'Invalid number of pins' unless (PINS[:MIN]..PINS[:MAX]).cover?(pins)
    raise StandardError, 'Too many pins in frame' unless valid_frame?(pins)
    raise StandardError, 'Game is over, no rolls allowed' if game_complete?
  end

  def valid_frame?(pins)
    last_roll_was_strike = @score_card[current_frame].last == 10

    (last_frame? && last_roll_was_strike || spare?) ||
      @score_card[current_frame].last.to_i + pins <= PINS[:MAX]
  end

  def score
    raise StandardError, 'Score unavailable until end of the game' unless game_complete?
    @score_card.values.map.with_index(1) do |f, i|
      score_frame(f, i)
    end.reduce(:+)
  end

  def score_frame(f, i)
    strike_or_spare = [f.first, f.inject(:+)].any? { |e| e == PINS[:MAX] }

    if strike_or_spare
      special(@score_card[i], @score_card[i + 1], @score_card[i + 2])
    else
      f.reduce(:+)
    end
  end

  def special(*frames)
    first_three_scores = 0..2
    frames.flatten[first_three_scores].reduce(:+)
  end

  def current_frame
    @score_card.keys.max
  end

  def game_complete?
    last_frame? && frame_complete?
  end

  def last_frame?
    current_frame == 10
  end

  def frame_complete?
    if last_frame?
      frame_filled && open_frame? || frame_filled(3)
    else
      frame_filled || strike?
    end
  end

  def frame_filled(rolls = 2)
    @score_card[current_frame].size == rolls
  end

  def open_frame?
    !(strike? || spare?)
  end

  def strike?
    @score_card[current_frame].first == 10
  end

  def spare?
    @score_card[current_frame].inject(:+) == 10
  end
end

Version data entries

6 entries across 6 versions & 1 rubygems

Version	Path
trackler-2.0.3.0	tracks/ruby/exercises/bowling/example.rb
trackler-2.0.2.0	tracks/ruby/exercises/bowling/example.rb
trackler-2.0.1.2	tracks/ruby/exercises/bowling/example.rb
trackler-2.0.1.1	tracks/ruby/exercises/bowling/example.rb
trackler-2.0.1.0	tracks/ruby/exercises/bowling/example.rb
trackler-2.0.0.10	tracks/ruby/exercises/bowling/example.rb