module DashedMap

# File lib/dashed_map.rb, line 4
def dashed_map(words, n=30)
  line_length = 0
  words.inject([]) do |list, word|

    # Get the length of the word
    word_size = word.size
    # Add 1 for the space preceding the word
    # There is no space added before the first word
    word_size += 1 unless list.empty?

    # If adding a word takes us over our limit,
    # join two words by a dash and insert that
    if word_size >= n
      word_pieces = []
      ((word_size / 15) + 1).times do |i|
        word_pieces << word[(i * 15)..(((i+1) * 15)-1)]
      end
      word = word_pieces.compact.select{|p| p.length > 0}.join('-')
      list << word
      line_length = word.size
    elsif (line_length + word_size >= n) and not list.empty?
      previous = list.pop
      previous ||= ''
      list << previous + '-' + word
      line_length = word_size
    # Otherwise just add the word to the list
    else
      list << word
      line_length += word_size
    end

    # Return the list so that inject works
    list
  end
end