bottles.rb

class Bottles
  def song
    verses(99, 0)
  end

  def verses(high, low)
    high.downto(low).map { |n| verse(n) }.join("\n")
  end

  def verse(n)
    [line1(n), line2(n)].join("\n") + "\n"
  end

  private

  def line1(n)
    "#{bottle_str(n).capitalize} of beer on the wall, #{bottle_str(n)} of beer."
  end

  def line2(n)
    if n > 0
      "Take #{it_one(n)} down and pass it around, #{bottle_str(n - 1)} of beer on the wall."
    else
      "Go to the store and buy some more, 99 bottles of beer on the wall."
    end
  end

  def it_one(n)
    n == 1 ? "it" : "one"
  end

  def count(n)
    n > 0 ? n : "no more"
  end

  def bottle_str(n)
    [count(n), bottle(n)].join(" ")
  end

  def bottle(n)
    n == 1 ? "bottle" : "bottles"
  end
end