module ReadingTimeFilter
  def reading_time(input)
    words_per_minute = 180

    words = input.split.size
    minutes = (words / words_per_minute).floor
    minutes_label = minutes === 1 ? ' minute' : ' minutes'
    minutes > 0 ? "about #{minutes} #{minutes_label}" : 'less than 1 minute'
  end
end

Liquid::Template.register_filter(ReadingTimeFilter)
