import 'package:flutter_test/flutter_test.dart';
import 'package:timbre/library/offline_library.dart';
import 'package:timbre/subsonic/models.dart';

/// Builds a downloaded-track [Song] with just the fields the offline
/// reconstruction reads. Everything else defaults to null.
Song _song(
  String id, {
  String? title,
  String? album,
  String? albumId,
  String? artist,
  String? artistId,
  String? coverArt,
  int? track,
  int? discNumber,
  int? year,
  String? genre,
}) =>
    Song(
      id: id,
      title: title,
      album: album,
      albumId: albumId,
      artist: artist,
      artistId: artistId,
      coverArt: coverArt,
      track: track,
      discNumber: discNumber,
      year: year,
      genre: genre,
    );

void main() {
  group('offline_library — album reconstruction', () {
    test('groups songs by albumId and synthesizes album metadata', () {
      final songs = [
        _song('1',
            title: 'A',
            album: 'Rumours',
            albumId: 'alb1',
            artist: 'Fleetwood Mac',
            artistId: 'art1',
            coverArt: 'cov1',
            track: 2,
            year: 1977,
            genre: 'Rock'),
        _song('2',
            title: 'B',
            album: 'Rumours',
            albumId: 'alb1',
            artist: 'Fleetwood Mac',
            artistId: 'art1',
            coverArt: 'cov1',
            track: 1,
            year: 1977,
            genre: 'Rock'),
      ];
      final albums = albumsFromSongs(songs);
      expect(albums, hasLength(1));
      final a = albums.single;
      expect(a.id, 'alb1');
      expect(a.name, 'Rumours');
      expect(a.artist, 'Fleetwood Mac');
      expect(a.artistId, 'art1');
      expect(a.coverArt, 'cov1');
      expect(a.year, 1977);
      expect(a.genre, 'Rock');
      expect(a.songCount, 2);
    });

    test('orders an album by disc then track, nulls last', () {
      final songs = [
        _song('1', album: 'X', albumId: 'x', title: 'no-track'),
        _song('2', album: 'X', albumId: 'x', title: 'd1t2', discNumber: 1, track: 2),
        _song('3', album: 'X', albumId: 'x', title: 'd2t1', discNumber: 2, track: 1),
        _song('4', album: 'X', albumId: 'x', title: 'd1t1', discNumber: 1, track: 1),
      ];
      final ids = albumsFromSongs(songs).single.songs.map((s) => s.title).toList();
      expect(ids, ['d1t1', 'd1t2', 'd2t1', 'no-track']);
    });

    test('falls back to album name as key and id when albumId is missing', () {
      final songs = [
        _song('1', album: 'Untitled Sessions', title: 'A'),
        _song('2', album: 'Untitled Sessions', title: 'B'),
      ];
      final albums = albumsFromSongs(songs);
      expect(albums, hasLength(1));
      expect(albums.single.id, 'Untitled Sessions');
      expect(albums.single.songCount, 2);
    });

    test('skips songs with no album identity', () {
      final songs = [
        _song('1', title: 'orphan'),
        _song('2', album: 'Real', albumId: 'r', title: 'kept'),
      ];
      final albums = albumsFromSongs(songs);
      expect(albums, hasLength(1));
      expect(albums.single.id, 'r');
    });

    test('sorts albums by name case-insensitively', () {
      final songs = [
        _song('1', album: 'zebra', albumId: 'z'),
        _song('2', album: 'Apple', albumId: 'a'),
        _song('3', album: 'mango', albumId: 'm'),
      ];
      final names = albumsFromSongs(songs).map((a) => a.name).toList();
      expect(names, ['Apple', 'mango', 'zebra']);
    });
  });

  group('offline_library — artist reconstruction', () {
    test('groups by artistId and nests albums', () {
      final songs = [
        _song('1',
            album: 'One',
            albumId: 'a1',
            artist: 'Radiohead',
            artistId: 'r',
            coverArt: 'c1'),
        _song('2',
            album: 'Two',
            albumId: 'a2',
            artist: 'Radiohead',
            artistId: 'r',
            coverArt: 'c2'),
      ];
      final artists = artistsFromSongs(songs);
      expect(artists, hasLength(1));
      final a = artists.single;
      expect(a.id, 'r');
      expect(a.name, 'Radiohead');
      expect(a.albumCount, 2);
      expect(a.albums.map((al) => al.id), containsAll(['a1', 'a2']));
      expect(a.coverArt, isNotNull);
    });

    test('falls back to artist name as key and id', () {
      final songs = [_song('1', album: 'X', albumId: 'x', artist: 'Nameless Band')];
      final artists = artistsFromSongs(songs);
      expect(artists.single.id, 'Nameless Band');
    });
  });

  group('offline_library — keyed lookups', () {
    final songs = [
      _song('1', album: 'One', albumId: 'a1', artist: 'Band', artistId: 'b1'),
      _song('2', album: 'Two', albumId: 'a2', artist: 'Band', artistId: 'b1'),
    ];

    test('albumFromSongs returns the matching album or null', () {
      expect(albumFromSongs(songs, 'a2')?.name, 'Two');
      expect(albumFromSongs(songs, 'nope'), isNull);
    });

    test('artistFromSongs returns the matching artist or null', () {
      final artist = artistFromSongs(songs, 'b1');
      expect(artist?.name, 'Band');
      expect(artist?.albumCount, 2);
      expect(artistFromSongs(songs, 'nope'), isNull);
    });
  });

  test('empty input yields empty output', () {
    expect(albumsFromSongs(const []), isEmpty);
    expect(artistsFromSongs(const []), isEmpty);
    expect(albumFromSongs(const [], 'x'), isNull);
    expect(artistFromSongs(const [], 'x'), isNull);
  });
}