updates

lib/library/browse_query.dart

@@ -0,0 +1,149 @@
+import '../settings/settings_store.dart';
+import '../subsonic/models.dart';
+
+/// Session-scoped filter for a browse view: an optional genre and release year.
+/// Held in `state/providers.dart` (not persisted) so the app never silently
+/// reopens filtered. Sort order *is* persisted (see [AppSettings]).
+class BrowseFilter {
+  const BrowseFilter({this.genre, this.year});
+
+  /// Case-insensitive genre match, or null for "all genres".
+  final String? genre;
+
+  /// Exact release-year match, or null for "all years".
+  final int? year;
+
+  bool get isActive => genre != null || year != null;
+
+  int get activeCount => (genre != null ? 1 : 0) + (year != null ? 1 : 0);
+
+  BrowseFilter copyWith({Object? genre = _unset, Object? year = _unset}) =>
+      BrowseFilter(
+        genre: identical(genre, _unset) ? this.genre : genre as String?,
+        year: identical(year, _unset) ? this.year : year as int?,
+      );
+
+  static const Object _unset = Object();
+}
+
+/// Distinct, display-cased genres from a set of raw genre strings, sorted
+/// alphabetically. Dedupes case-insensitively (keeping first-seen casing) so a
+/// server that mixes "Rock"/"rock" collapses to one entry.
+List<String> distinctGenres(Iterable<String?> raw) {
+  final byKey = <String, String>{};
+  for (final g in raw) {
+    final v = g?.trim();
+    if (v == null || v.isEmpty) continue;
+    byKey.putIfAbsent(v.toLowerCase(), () => v);
+  }
+  final out = byKey.values.toList()
+    ..sort((a, b) => a.toLowerCase().compareTo(b.toLowerCase()));
+  return out;
+}
+
+/// Distinct release years present, newest first.
+List<int> distinctYears(Iterable<int?> raw) {
+  final set = <int>{};
+  for (final y in raw) {
+    if (y != null && y > 0) set.add(y);
+  }
+  final out = set.toList()..sort((a, b) => b.compareTo(a));
+  return out;
+}
+
+bool _genreMatches(String? itemGenre, String? filterGenre) {
+  if (filterGenre == null) return true;
+  return itemGenre != null &&
+      itemGenre.toLowerCase() == filterGenre.toLowerCase();
+}
+
+int _byString(String? a, String? b) =>
+    (a ?? '').toLowerCase().compareTo((b ?? '').toLowerCase());
+
+/// Compare where a null [a]/[b] always sorts *last*, regardless of [descending].
+/// Takes bare [Comparable] so both `int` (`Comparable<num>`) and `DateTime` work.
+int _nullsLast(Comparable? a, Comparable? b, {bool descending = false}) {
+  if (a == null && b == null) return 0;
+  if (a == null) return 1;
+  if (b == null) return -1;
+  final c = a.compareTo(b);
+  return descending ? -c : c;
+}
+
+/// Filter then sort albums for the browse grid. Pure — no I/O.
+List<Album> applyAlbumQuery(
+  List<Album> albums,
+  BrowseFilter filter,
+  AlbumSort sort,
+) {
+  final out = albums
+      .where((a) => _genreMatches(a.genre, filter.genre))
+      .where((a) => filter.year == null || a.year == filter.year)
+      .toList();
+
+  switch (sort) {
+    case AlbumSort.nameAsc:
+      out.sort((a, b) => _byString(a.name, b.name));
+    case AlbumSort.artistAsc:
+      out.sort((a, b) {
+        final c = _byString(a.artist, b.artist);
+        return c != 0 ? c : _byString(a.name, b.name);
+      });
+    case AlbumSort.yearDesc:
+      out.sort((a, b) {
+        final c = _nullsLast(a.year, b.year, descending: true);
+        return c != 0 ? c : _byString(a.name, b.name);
+      });
+    case AlbumSort.yearAsc:
+      out.sort((a, b) {
+        final c = _nullsLast(a.year, b.year);
+        return c != 0 ? c : _byString(a.name, b.name);
+      });
+    case AlbumSort.recentlyAdded:
+      out.sort((a, b) {
+        final c = _nullsLast(a.createdAt, b.createdAt, descending: true);
+        return c != 0 ? c : _byString(a.name, b.name);
+      });
+  }
+  return out;
+}
+
+/// Filter then sort tracks for the browse list. Pure — no I/O.
+List<Song> applyTrackQuery(
+  List<Song> songs,
+  BrowseFilter filter,
+  TrackSort sort,
+) {
+  final out = songs
+      .where((s) => _genreMatches(s.genre, filter.genre))
+      .where((s) => filter.year == null || s.year == filter.year)
+      .toList();
+
+  switch (sort) {
+    case TrackSort.titleAsc:
+      out.sort((a, b) => _byString(a.title, b.title));
+    case TrackSort.artistAsc:
+      out.sort((a, b) {
+        final c = _byString(a.artist, b.artist);
+        return c != 0 ? c : _byString(a.title, b.title);
+      });
+    case TrackSort.albumAsc:
+      out.sort((a, b) {
+        final c = _byString(a.album, b.album);
+        if (c != 0) return c;
+        final t = _nullsLast(a.track, b.track);
+        return t != 0 ? t : _byString(a.title, b.title);
+      });
+    case TrackSort.yearDesc:
+      out.sort((a, b) {
+        final c = _nullsLast(a.year, b.year, descending: true);
+        return c != 0 ? c : _byString(a.title, b.title);
+      });
+    case TrackSort.recentlyAdded:
+      out.sort((a, b) {
+        final c = _nullsLast(a.createdAt, b.createdAt, descending: true);
+        return c != 0 ? c : _byString(a.title, b.title);
+      });
+  }
+  return out;
+}