from subprocess import call, Popen, PIPE
from os import listdir, remove
from os.path import splitext
from re import match
from sys import argv
from enum import Enum
from datetime import timedelta
from math import ceil



class Stream(Enum):
    AUDIO = 1
    VIDEO = 2

class File(Enum):
    LIST = 1
    LOOP = 2
    OUTPUT = 3

def getCmdStdErr(command):
    process = Popen(command, stderr=PIPE, stdout=PIPE)
    out, err = process.communicate()
    return err

def getDuration(ffprobe_output):
    durationPattern = r'.*Duration:\s(.+),\sstart.*'
    regex = match(durationPattern, str(ffprobe_output))
    duration = regex.groups()[0] if regex else None
    if not duration:
        raise ValueError('Cannot process ffprobe output!')
    return duration


argv.append('https://coub.com/view/aeeuu')  # TODO: remove debug line

FILES = {Stream.AUDIO: 'audio', Stream.VIDEO: 'video',
         File.LIST: 'list.txt', File.LOOP: 'loop', File.OUTPUT: 'output.mp4'}
OUTPUT_KEYS = [File.OUTPUT]
URL = argv[1] if len(argv) > 0 else ''  # youtube-dl error message will be shown if ''


call(('/usr/bin/env', 'youtube-dl', '--extract-audio',
                                    '--output',         '{}.%(ext)s'.format(FILES[Stream.AUDIO]),
                                    URL))
call(('/usr/bin/env', 'youtube-dl', '--output',         '{}.%(ext)s'.format(FILES[Stream.VIDEO]),
                                    URL))

for file in listdir():
    for filename in FILES:
        if match('^{}.*'.format(FILES[filename]), file):
            FILES[filename] = file

audioData= getDuration(getCmdStdErr(('/usr/bin/env', 'ffprobe', FILES[Stream.AUDIO]))).split(':')
videoData = getDuration(getCmdStdErr(('/usr/bin/env', 'ffprobe', FILES[Stream.VIDEO]))).split(':')

audioLen = timedelta(hours=float(audioData[0]), minutes=float(audioData[1]), seconds=float(audioData[2]))
videoLen = timedelta(hours=float(videoData[0]), minutes=float(videoData[1]), seconds=float(videoData[2]))

longer = audioLen if audioLen > videoLen else videoLen
shorter = audioLen if audioLen < videoLen else videoLen
shorterFile = FILES[Stream.AUDIO] if audioLen < videoLen else FILES[Stream.VIDEO]
FILES[File.LOOP] += splitext(shorterFile)[1]

timesLoop = ceil(longer.seconds / shorter.seconds)

with open(FILES[File.LIST], 'w') as f:
    for i in range(timesLoop):
        print("file '{}'".format(shorterFile), file=f)


call(('/usr/bin/env', 'ffmpeg', '-f', 'concat', '-i', FILES[File.LIST], '-c', 'copy', FILES[File.LOOP]))
call(('/usr/bin/env', 'ffmpeg', '-i', FILES[File.LOOP],
                                '-i', FILES[Stream.AUDIO],
                                '-map', '0', '-map', '1',
                                '-c', 'copy', FILES[File.OUTPUT]))

for key in FILES:
    if key not in OUTPUT_KEYS:
        remove(FILES[key])