Ruby: Convert seconds to HH:MM:SS time notation without will resetting HH to 00 when crossing 24-hour day boundary.

formatted_duration.rb

# Will take as input a time in seconds (which is typically a result after subtracting two Time objects),
# and return the result in HH:MM:SS, but instead of resetting HH to 00 when the time exceeds a 24 hour period,
# it will increase it indefinitely. For other variations, see discussion here: https://gist.github.com/shunchu/3175001
def formatted_duration(total_seconds)
  total_seconds = total_seconds.round # to avoid fractional seconds to potentially compound and mess up seconds, minutes and hours
  hours = total_seconds / (60*60)
  minutes = (total_seconds / 60) % 60  # the modulo operator (%) gives the remainder when leftside is divided by rightside
  seconds = total_seconds % 60
  [hours, minutes, seconds].map do |t|
    # Right justify and pad with 0 until length is 2. 
    # So if the duration of any of the time components is 0, then it will display as 00
    t.round.to_s.rjust(2,'0')
  end.join(':')
end