gistfile1.rb

class TimeHelper
  class << self
    def time_difference(time_start, time_end)
      total_seconds = Integer(time_end - time_start)

      seconds = (total_seconds % 60)
      minutes = (total_seconds - seconds) / 60
      hours = (minutes - (minutes % 60)) / 60
      minutes = minutes - hours * 60
      result = []
      result << get_string_for_number("hour", hours) if hours > 0
      result << get_string_for_number("minute", minutes) if minutes > 0
      result << get_string_for_number("second", seconds) if seconds > 0
      result.join(" ")
    end

    def get_string_for_number(name, number)
      result = number.to_s + " " + name
      result = result + "s" if number != 1
      result
    end
  end
end