#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import mutagen
import mutagen.id3
import mutagen.mp4
import os
import re
import subprocess
import sys

import symuid

# freeform keys start with '----'
# http://mutagen.readthedocs.io/en/latest/api/mp4.html
TRACK_UUID_MP4_TAG = '----:symuid:uuid'
PATH_DEFAULT_IGNORE_REGEX = r'\.(itdb|itc2|itl|jpg|midi?|plist|xml|zip)$'


def generate_uuid():
    return subprocess.check_output(['uuid', '-v', '4', '-F', 'BIN']).strip()


def get_or_assign_uuid_id3(track):
    uuid = track._iface.get_uuid()
    if uuid is None:
        id3_tags = track._iface._mutagen_file.tags
        # mutagen.id3._specs.EncodedTextSpec.write encodes 'owner'
        id3_tags.add(mutagen.id3.UFID(
            owner=track._iface._UFID_OWNER_ID,
            data=generate_uuid(),
        ))
        id3_tags.save()
        id3_tags.load(filename=id3_tags.filename)
        uuid = track._iface.get_uuid()
        print("{!r}: assigned uuid {!r}".format(id3_tags.filename, uuid))
        assert uuid is not None
    return uuid


def get_or_assign_uuid_mp4(mp4_file):
    if not TRACK_UUID_MP4_TAG in mp4_file:
        mp4_file[TRACK_UUID_MP4_TAG] = mutagen.mp4.MP4FreeForm(
            data=generate_uuid(),
            # https://mutagen.readthedocs.io/en/latest/api/mp4.html#mutagen.mp4.AtomDataType.UUID
            dataformat=mutagen.mp4.AtomDataType.UUID,
        )
        mp4_file.save()
        mp4_file.load(filename=mp4_file.filename)
        print("{!r}: assigned uuid {!r}".format(
            mp4_file.filename, mp4_file[TRACK_UUID_MP4_TAG][0],
        ))
    return mp4_file[TRACK_UUID_MP4_TAG][0]


def log_path(track_path, msg, stream=sys.stdout):
    stream.write("{!r}: {}\n".format(track_path, msg))


def log_path_error(track_path, msg):
    log_path(track_path, msg, stream=sys.stderr)


def symuid_sync(path, path_ignore_regex, show_ignored=False):
    for track in symuid.Track.walk(
            root_path=path,
            path_ignore_regex=path_ignore_regex,
            ignored_cb=lambda p: show_ignored and log_path(p, 'ignored'),
            unsupported_cb=lambda p, e: log_path_error(p, 'unsupported type, skipped'),
        ):
        if isinstance(track._iface, symuid.tag_interface.MP4):
            get_or_assign_uuid_mp4(track._iface._mutagen_file)
        elif isinstance(track._iface, symuid.tag_interface.ID3):
            get_or_assign_uuid_id3(track)
        else:
            raise Exception(track)


def _init_argparser():
    import argparse
    argparser = argparse.ArgumentParser(description=None)
    argparser.add_argument('path')
    argparser.add_argument(
        '--path-ignore-regex',
        default=PATH_DEFAULT_IGNORE_REGEX,
        nargs=1,
        metavar='pattern',
        dest='path_ignore_regex',
        type=lambda pattern: re.compile(pattern),
        help='(default: %(default)s)',
    )
    argparser.add_argument(
        '--show-ignored',
        action='store_true',
    )
    return argparser


def main(argv):
    argparser = _init_argparser()
    args = argparser.parse_args(argv[1:])
    symuid_sync(**vars(args))
    return 0

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