bottles_short.rb

bottle_lyric = ->(count) { "#{count} #{count == 1 ? "bottle" : "bottles"} of beer" }

99.downto(2) do |c|
  puts "#{bottle_lyric.call(c)} on the wall,"
  puts "#{bottle_lyric.call(c)}!"
  puts "Take one down, pass it around"
  puts "#{bottle_lyric.call(c-1)} on the wall!" 
  puts 
end

puts "1 bottle of beer on the wall,"
puts "1 bottle of beer!"
puts "Take one down, pass it around,"
puts "No more bottles of beer on the wall :-("   

bottlesofbeer.rb

class BottlesOfBeer
  attr_reader :bottles_in_the_bar
  def initialize(bottles_in_the_bar)
    @bottles_in_the_bar = bottles_in_the_bar
  end

  def count_off
    bottles_in_the_bar.downto(2) do |number|
      current_beer_count = beer_count_lyric(number)
      next_beer_count = beer_count_lyric(number - 1)

      puts "#{current_beer_count} on the wall, 
      #{current_beer_count}! 
      Take one down, pass it around, 
      #{next_beer_count} on the wall!"   
    end
    sing_final!
  end

  def sing_final!
    puts "1 bottle of beer on the wall, 
      1 bottle of beer! 
      Take one down, pass it around, 
      No more bottles of beer on the wall :-("   
  end

  private
  def beer_count_lyric(beer_bottle_count)
    "#{pluralize('bottle', beer_bottle_count)} of beer"
  end


  def pluralize(word, count)
    "#{count} #{word}".tap do |p|
      p << "s" if count != 1
    end
  end
end

puts "How many bottles of beer have you got? "
bottles_in_the_bar = gets.to_i
bottle = BottlesOfBeer.new(bottles_in_the_bar)
bottle.count_off