# This file is part of beets.
# Copyright 2016, Pedro Silva.
# Copyright 2017, Quentin Young.
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.

"""List missing tracks."""

from collections import defaultdict
from collections.abc import Iterator

import musicbrainzngs
from musicbrainzngs.musicbrainz import MusicBrainzError

from beets import config, metadata_plugins
from beets.dbcore import types
from beets.library import Album, Item, Library
from beets.plugins import BeetsPlugin
from beets.ui import Subcommand, print_

MB_ARTIST_QUERY = r"mb_albumartistid::^\w{8}-\w{4}-\w{4}-\w{4}-\w{12}$"


def _missing_count(album):
    """Return number of missing items in `album`."""
    return (album.albumtotal or 0) - len(album.items())


def _item(track_info, album_info, album_id):
    """Build and return `item` from `track_info` and `album info`
    objects. `item` is missing what fields cannot be obtained from
    MusicBrainz alone (encoder, rg_track_gain, rg_track_peak,
    rg_album_gain, rg_album_peak, original_year, original_month,
    original_day, length, bitrate, format, samplerate, bitdepth,
    channels, mtime.)
    """
    t = track_info
    a = album_info

    return Item(
        **{
            "album_id": album_id,
            "album": a.album,
            "albumartist": a.artist,
            "albumartist_credit": a.artist_credit,
            "albumartist_sort": a.artist_sort,
            "albumdisambig": a.albumdisambig,
            "albumstatus": a.albumstatus,
            "albumtype": a.albumtype,
            "artist": t.artist,
            "artist_credit": t.artist_credit,
            "artist_sort": t.artist_sort,
            "asin": a.asin,
            "catalognum": a.catalognum,
            "comp": a.va,
            "country": a.country,
            "day": a.day,
            "disc": t.medium,
            "disctitle": t.disctitle,
            "disctotal": a.mediums,
            "label": a.label,
            "language": a.language,
            "length": t.length,
            "mb_albumid": a.album_id,
            "mb_artistid": t.artist_id,
            "mb_releasegroupid": a.releasegroup_id,
            "mb_trackid": t.track_id,
            "media": t.media,
            "month": a.month,
            "script": a.script,
            "title": t.title,
            "track": t.index,
            "tracktotal": len(a.tracks),
            "year": a.year,
        }
    )


class MissingPlugin(BeetsPlugin):
    """List missing tracks"""

    album_types = {
        "missing": types.INTEGER,
    }

    def __init__(self):
        super().__init__()

        self.config.add(
            {
                "count": False,
                "total": False,
                "album": False,
            }
        )

        self.album_template_fields["missing"] = _missing_count

        self._command = Subcommand("missing", help=__doc__, aliases=["miss"])
        self._command.parser.add_option(
            "-c",
            "--count",
            dest="count",
            action="store_true",
            help="count missing tracks per album",
        )
        self._command.parser.add_option(
            "-t",
            "--total",
            dest="total",
            action="store_true",
            help="count total of missing tracks",
        )
        self._command.parser.add_option(
            "-a",
            "--album",
            dest="album",
            action="store_true",
            help="show missing albums for artist instead of tracks",
        )
        self._command.parser.add_format_option()

    def commands(self):
        def _miss(lib, opts, args):
            self.config.set_args(opts)
            albms = self.config["album"].get()

            helper = self._missing_albums if albms else self._missing_tracks
            helper(lib, args)

        self._command.func = _miss
        return [self._command]

    def _missing_tracks(self, lib, query):
        """Print a listing of tracks missing from each album in the library
        matching query.
        """
        albums = lib.albums(query)

        count = self.config["count"].get()
        total = self.config["total"].get()
        fmt = config["format_album" if count else "format_item"].get()

        if total:
            print(sum([_missing_count(a) for a in albums]))
            return

        # Default format string for count mode.
        if count:
            fmt += ": $missing"

        for album in albums:
            if count:
                if _missing_count(album):
                    print_(format(album, fmt))

            else:
                for item in self._missing(album):
                    print_(format(item, fmt))

    def _missing_albums(self, lib: Library, query: list[str]) -> None:
        """Print a listing of albums missing from each artist in the library
        matching query.
        """
        query.append(MB_ARTIST_QUERY)

        # build dict mapping artist to set of their album ids in library
        album_ids_by_artist = defaultdict(set)
        for album in lib.albums(query):
            # TODO(@snejus): Some releases have different `albumartist` for the
            # same `mb_albumartistid`. Since we're grouping by the combination
            # of these two fields, we end up processing the same
            # `mb_albumartistid` multiple times: calling MusicBrainz API and
            # reporting the same set of missing albums. Instead, we should
            # group by `mb_albumartistid` field only.
            artist = (album["albumartist"], album["mb_albumartistid"])
            album_ids_by_artist[artist].add(album)

        total_missing = 0
        calculating_total = self.config["total"].get()
        for (artist, artist_id), album_ids in album_ids_by_artist.items():
            try:
                resp = musicbrainzngs.browse_release_groups(artist=artist_id)
            except MusicBrainzError as err:
                self._log.info(
                    "Couldn't fetch info for artist '{}' ({}) - '{}'",
                    artist,
                    artist_id,
                    err,
                )
                continue

            missing_titles = [
                f"{artist} - {rg['title']}"
                for rg in resp["release-group-list"]
                if rg["id"] not in album_ids
            ]

            if calculating_total:
                total_missing += len(missing_titles)
            else:
                for title in missing_titles:
                    print(title)

        if calculating_total:
            print(total_missing)

    def _missing(self, album: Album) -> Iterator[Item]:
        """Query MusicBrainz to determine items missing from `album`."""
        if len(album.items()) == album.albumtotal:
            return

        item_mbids = {x.mb_trackid for x in album.items()}
        # fetch missing items
        # TODO: Implement caching that without breaking other stuff
        if album_info := metadata_plugins.album_for_id(album.mb_albumid):
            for track_info in album_info.tracks:
                if track_info.track_id not in item_mbids:
                    self._log.debug(
                        "track {0} in album {1}",
                        track_info.track_id,
                        album_info.album_id,
                    )
                    yield _item(track_info, album_info, album.id)
