bowlinggame

gistfile1.txt

class BowlingGame
  attr_reader :rolls

  def initialize(rolls)
    @rolls = rolls
  end

  def score
    (1..10).reduce([]) { |frame_calc_a, frame_number|
      frame_calc_a << rolls[range(frame_number)]
    }.flatten.reduce(:+)
  end

  def range(frame_number)
    first_i = (frame_number - 1) * 2
    second_i = first_i + 1
    return (first_i..second_i + 3) if frame_number <= 8 and double_strike?(first_i)
    return (first_i..second_i + 2) if strike?(first_i)
    return (first_i..second_i + 1) if spare?(first_i)
    (first_i..second_i)
  end

  def spare?(first_i)
    (rolls[first_i] + rolls[first_i + 1]) == 10 and !strike?(first_i)
  end

  def strike?(first_i)
    rolls[first_i] == 10
  end

  def double_strike?(first_i)
    strike?(first_i) and strike?(first_i + 2)
  end
end