#!/usr/bin/env python2
#
# Quick and dirty ffmpeg command crafter
#
# Outputs the ffmpeg command to encode your raw MPEG2 Video file with h264 into
# a matroska container. You can optionally select start/end time and a specific
# audio tracks (e.g ac3).
# 
# Copyright (c) 2014 by ManiacTwister
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#


import sys, getopt, time, os
try:
  from ffprobe import FFProbe
except ImportError:
  raise ImportError('Please install the python ffprobe package. E.g with: sudo pip2 install ffprobe')

def printHelp(argv):
  print argv[0] + ' -i <inputfile> -o <outputfile> [-s <start hh:mm:ss> -e <end hh:mm:ss> -ac <audio codec name> --overwrite]'

def errorMsg(msg):
  print msg
  sys.exit(2)

def isTimeFormat(input):
  try:
    time.strptime(input, '%H:%M:%S')
    return True
  except ValueError:
    return False

def main(argv):
  ffmpeg_args = ["ffmpeg", "-i"]
  inputfile = ''
  outputfile = ''
  start = None
  end = None
  acodec = None
  overwrite = False
  audio_index = None

  try:
    opts, args = getopt.getopt(argv[1:],"hi:o:s:e:a:f",["ifile=","ofile=","start=","end=","acodec=", "overwrite"])
  except getopt.GetoptError:
    printHelp(argv)
    sys.exit(2)
  for opt, arg in opts:
    if opt == '-h':
      printHelp(argv)
      sys.exit()
    elif opt in ("-i", "--ifile"):
      inputfile = arg
    elif opt in ("-o", "--ofile"):
      outputfile = arg
    elif opt in ("-s", "--start"):
      start = arg
    elif opt in ("-e", "--end"):
      end = arg
    elif opt in ("-a", "--acodec"):
      acodec = arg
    elif opt in ("-f", "--overwrite"):
      overwrite = True

  if not os.path.isfile(inputfile):
    errorMsg("Input file '" + inputfile + "' doesn't exist")
  if os.path.isfile(outputfile) and not overwrite:
    errorMsg("Input file '" + inputfile + "' does exist. Use -f to overwrite")

  ffmpeg_args.append(inputfile)
  ffmpeg_args.append("-sn")

  # Append start and end time
  if start is not None:
    if isTimeFormat(start):
      ffmpeg_args.append("-ss " + start)
    else:
      errorMsg("Start time '" + start + "' has wrong format")
  if end is not None:
    if isTimeFormat(end):
      ffmpeg_args.append("-to " + end)
    else:
      errorMsg("End time '" + end + "' has wrong format")

  ffmpeg_args.append("-c:v libx264 -map 0:0 -c:a copy")

  # Append audio stream
  if acodec is not None:
    metadata=FFProbe(inputfile)
    for stream in metadata.streams:
      if stream.isAudio() and stream.codec() == acodec:
        audio_index = stream.__dict__['index']
        break
    if audio_index is None:
      errorMsg("Audio stream with codec '" + acodec + "' not found")
    ffmpeg_args.append("-map 0:" + audio_index)

  ffmpeg_args.append("-f matroska")
  ffmpeg_args.append(outputfile)

  print 'Your ffmpeg command:'
  print ' '.join(ffmpeg_args)


if __name__ == "__main__":
  main(sys.argv)