99bottles.ex

defmodule Bottles do
  def song, do: verses(99, 0)

  def verses(first, last) do
    Enum.map_join first..last, "\n", &verse/1
  end

  def verse(0) do
    """
    No more bottles of beer on the wall, no more bottles of beer.
    Go to the store and buy some more, 99 bottles of beer on the wall.
    """
  end

  def verse(n) do
    """
    #{bottles(n)} of beer on the wall, #{bottles(n)} of beer.
    Take one down and pass it around, #{bottles(n - 1)} of beer on the wall.
    """
  end

  defp bottles(0), do: "No more bottles"
  defp bottles(1), do: "1 bottle"
  defp bottles(n), do: "#{n} bottles"
end