symuid/symuid-import-cmus

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

import datetime as dt
import os
import symuid
import symuid.library.cmus

FILE_PREFIX = b'CTC'
VERSION_LENGTH = 1
SUPPORTED_VERSION = b'\x0c'
# always big endian, see cache_init()
FLAGS_BYTEORDER = 'big'
FLAGS_LENGTH = 4
FLAG_64_BIT = 0x01


def import_track(cmus_track):
    if cmus_track.play_count > 0:
        print(cmus_track.play_count, cmus_track.path)


def symuid_import_cmus(cache_path):
    with open(os.path.expanduser(cache_path), 'rb') as cache:
        # see cache.c cache_init()
        assert cache.read(len(FILE_PREFIX)) == FILE_PREFIX
        cache_version = cache.read(VERSION_LENGTH)
        assert cache_version == SUPPORTED_VERSION, cache_version
        flags = int.from_bytes(
            cache.read(FLAGS_LENGTH),
            byteorder=FLAGS_BYTEORDER,  # persistent
        )
        assert flags & FLAG_64_BIT
        # support no other flags
        assert flags & ~FLAG_64_BIT == 0, flags
        # size includes size itself
        while True:
            size = symuid.library.cmus._int_from_bytes_sys(cache.read(4))
            if size == 0:
                break
            cmus_track = symuid.library.cmus.Track(size, cache.read(size - 4))
            import_track(cmus_track)
            # see cache.c write_ti ALIGN
            cache.read((-size) % 8)


def _init_argparser():
    import argparse
    argparser = argparse.ArgumentParser(description=None)
    argparser.add_argument(
        'cache_path',
        nargs='?',
        default='~/.config/cmus/cache',
        help='(default: %(default)r)',
    )
    return argparser


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

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