import argparse
import re
import typing

import symuid


def _walk_track_attrs(path, path_ignore_regex) -> typing.Iterator[dict]:
    for track in symuid.Track.walk(path, path_ignore_regex):
        yield {'path': track.path,
               'comment': track.comment,
               'play_count': track.get_play_count_sum()}

def _init_argparser():
    argparser = argparse.ArgumentParser(description='filter & sort tracks')
    argparser.add_argument('path')
    argparser.add_argument(
        '--path-ignore-regex',
        default=symuid.Track.PATH_DEFAULT_IGNORE_REGEX,
        dest='path_ignore_regex',
        nargs=1,
        type=re.compile,
        metavar='pattern',
        help='(default: %(default)s)',
    )
    argparser.add_argument(
        '--filter',
        metavar='expression',
        dest='filter_expression',
        help='(example: {!r} or {!r})'.format(
            "play_count > 16 and path.endswith('.mp3')",
            "comment is None or len(comment) < 16",
        ),
    )
    argparser.add_argument(
        '--sort',
        metavar='expression',
        dest='sort_expression',
        help='(example: {!r} or {!r})'.format(
            "play_count * -1",
            "(play_count, len(path))",
        ),
    )
    argparser.add_argument(
        '--limit',
        type=int,
        help='(default: none)',
    )
    argparser.add_argument(
        '--prefix',
        type=str,
        default='',
        help='add prefix to each resulting path (default: %(default)r)',
    )
    return argparser


def _main():
    args = _init_argparser().parse_args()
    # use generators until sort is required
    track_attrs = _walk_track_attrs(path=args.path, path_ignore_regex=args.path_ignore_regex)
    # pylint: disable=eval-used
    if args.filter_expression:
        track_attrs = filter(lambda a: eval(args.filter_expression, a), track_attrs)
    if args.sort_expression:
        track_attrs = sorted(track_attrs, key=lambda a: eval(args.sort_expression, a))
    for track_index, attr in enumerate(track_attrs):
        if args.limit and track_index == args.limit:
            break
        print(args.prefix + attr['path'])