#!/usr/bin/env python3

import sys
import os
import subprocess

import mutagen
from mutagen.id3 import ID3, CTOC, CHAP, TIT2, CTOCFlags


def time_to_milliseconds(time_str):
    time_parts = list(map(lambda t: float(t), time_str.split(':')))
    time = 0
    for part in time_parts[:-1]:
        time = part + time * 60

    time = int((time_parts[-1] + time) * 1000)

    return time


def read_chapter_file(chapter_file):
    chapters = []

    if not os.path.isfile(chapter_file):
        raise RuntimeError("Chapter file %s does not exist" % chapter_file)

    for line in open(chapter_file, "r"):
        line = line.strip()
        if line != "":
            time, name = line.split(maxsplit=1)
            chapters += [(time, name)]

    return chapters


def make_mp3_chapters(chapters, audio):
    file_length = int(audio.info.length * 1000)

    element_ids = [(u"ch%d" % i) for i in range(0, len(chapters))]

    audio.tags.add(CTOC(element_id = u"toc",
                    flags = CTOCFlags.TOP_LEVEL | CTOCFlags.ORDERED,
                    child_element_ids = element_ids,
                    sub_frames = [
                        TIT2(text = [u"TOC"]),
                    ]))

    for i in range(0, len(chapters)):
        start_time, name = chapters[i]
        start_time = time_to_milliseconds(start_time)

        end_time = file_length - 1
        if i < len(chapters) - 1:
            end_time = time_to_milliseconds(chapters[i+1][0])

        audio.tags.add(CHAP(element_id = u"chp%d" % i, start_time = start_time, end_time = end_time,
                        sub_frames = [
                            TIT2(text = [name]),
                        ]))


def make_mp4_chapters(chapters, path):
    chap_path = "%s.chapters.txt" % os.path.splitext(path)[0]
    chapter_file = open(chap_path, 'w')
    lines = [u"%s %s\n" % (start_time, name) for start_time, name in chapters]
    chapter_file.writelines(lines)
    chapter_file.close()

    popen = subprocess.Popen(["mp4chaps", "-i", path])
    popen.wait()

    os.remove(chap_path)


def make_ogg_chapters(chapters, audio):
    for i in range(0, len(chapters)):
        num = str(i).zfill(3)
        audio.tags['CHAPTER%s' % num] = chapters[i][0]
        audio.tags['CHAPTER%sNAME' % num] = chapters[i][1]



def main():

    if len(sys.argv) < 3:
        print("Usage: %s chapterfile mediafile1 mediafile2 mediafile3 ..." % sys.argv[0])
        sys.exit(0)

    chapter_file_path = sys.argv[1]
    media_files = sys.argv[1:]


    chapters = read_chapter_file(chapter_file_path)

    for path in media_files:
        print("Adding chapters to: %s" % path)
        audio = mutagen.File(path)

        if isinstance(audio, mutagen.mp3.MP3):
            make_mp3_chapters(chapters, audio)
            audio.save()
        elif isinstance(audio, mutagen.mp4.MP4):
            make_mp4_chapters(chapters, path)
        elif isinstance(audio, mutagen.oggvorbis.OggVorbis) or isinstance(audio, mutagen.oggopus.OggOpus):
            make_ogg_chapters(chapters, audio)
            audio.save()
        else:
            print("Skipping unsupported file: %s" % path)




if __name__ == '__main__':
    main()