fix(metadata): support extension custom search

lib/providers/extension_models.dart

@@ -361,6 +361,20 @@ class SearchFilter {
   }
 }
 
+String canonicalExtensionSearchFilterId(String value) {
+  final normalized = value.trim().toLowerCase().replaceAll(
+    RegExp(r'[^a-z0-9]+'),
+    '',
+  );
+  return switch (normalized) {
+    'track' || 'tracks' || 'song' || 'songs' || 'music' => 'track',
+    'artist' || 'artists' => 'artist',
+    'album' || 'albums' => 'album',
+    'playlist' || 'playlists' => 'playlist',
+    _ => normalized,
+  };
+}
+
 class SearchBehavior {
   final bool enabled;
   final String? placeholder;
@@ -399,6 +413,23 @@ class SearchBehavior {
     );
   }
 
+  String? filterIdForKind(String kind) {
+    final canonicalKind = canonicalExtensionSearchFilterId(kind);
+    for (final filter in filters) {
+      if (canonicalExtensionSearchFilterId(filter.id) == canonicalKind ||
+          (filter.label != null &&
+              canonicalExtensionSearchFilterId(filter.label!) ==
+                  canonicalKind) ||
+          (filter.icon != null &&
+              canonicalExtensionSearchFilterId(filter.icon!) ==
+                  canonicalKind)) {
+        final id = filter.id.trim();
+        if (id.isNotEmpty) return id;
+      }
+    }
+    return null;
+  }
+
   (double, double) getThumbnailSize({double defaultSize = 56}) {
     if (thumbnailWidth != null && thumbnailHeight != null) {
       return (thumbnailWidth!.toDouble(), thumbnailHeight!.toDouble());

lib/screens/home_search_logic.dart

@@ -183,32 +183,11 @@ class HomeSearchProviderPolicy {
       return null;
     }
 
-    return filters
-        .where(
-          (candidate) =>
-              canonicalFilterId(candidate.id) == canonicalFilter ||
-              (candidate.label != null &&
-                  canonicalFilterId(candidate.label!) == canonicalFilter) ||
-              (candidate.icon != null &&
-                  canonicalFilterId(candidate.icon!) == canonicalFilter),
-        )
-        .firstOrNull
-        ?.id;
+    return extension?.searchBehavior?.filterIdForKind(canonicalFilter);
   }
 
-  static String canonicalFilterId(String value) {
-    final normalized = value.trim().toLowerCase().replaceAll(
-      RegExp(r'[^a-z0-9]+'),
-      '',
-    );
-    return switch (normalized) {
-      'track' || 'tracks' || 'song' || 'songs' || 'music' => 'track',
-      'artist' || 'artists' => 'artist',
-      'album' || 'albums' => 'album',
-      'playlist' || 'playlists' => 'playlist',
-      _ => normalized,
-    };
-  }
+  static String canonicalFilterId(String value) =>
+      canonicalExtensionSearchFilterId(value);
 
   static String? preferredFilter(
     String preferredSearchTab,

lib/screens/track_metadata_edit_sheet.dart

@@ -870,16 +870,17 @@ class _EditMetadataSheetState extends State<_EditMetadataSheet> {
         context,
         listen: false,
       ).read(extensionProvider);
-      final selectedProviderId =
-          configuredProviderId != null &&
-              extensionState.extensions.any(
-                (extension) =>
-                    extension.id == configuredProviderId &&
-                    extension.enabled &&
-                    extension.hasMetadataProvider,
-              )
-          ? configuredProviderId
-          : null;
+      final selectedProvider = configuredProviderId == null
+          ? null
+          : extensionState.extensions
+                .where(
+                  (extension) =>
+                      extension.id == configuredProviderId &&
+                      extension.enabled &&
+                      extension.hasMetadataProvider,
+                )
+                .firstOrNull;
+      final selectedProviderId = selectedProvider?.id;
       final usesAutomaticProvider =
           selectedProviderId == null || selectedProviderId.isEmpty;
       final shouldFetchLyrics = _autoFillFields.contains('lyrics');
@@ -920,16 +921,31 @@ class _EditMetadataSheetState extends State<_EditMetadataSheet> {
 
       if (needsTrackLookup && best == null) {
         final query = queryParts.join(' ');
-        final results = usesAutomaticProvider
-            ? await PlatformBridge.searchTracksWithMetadataProviders(
-                query,
-                limit: 5,
-              )
-            : await PlatformBridge.searchTracksWithMetadataProvider(
-                selectedProviderId,
-                query,
-                limit: 5,
-              );
+        final List<Map<String, dynamic>> results;
+        if (usesAutomaticProvider) {
+          results = await PlatformBridge.searchTracksWithMetadataProviders(
+            query,
+            limit: 5,
+          );
+        } else if (selectedProvider!.hasCustomSearch) {
+          final trackFilter = selectedProvider.searchBehavior?.filterIdForKind(
+            'track',
+          );
+          results = await PlatformBridge.customSearchWithExtension(
+            selectedProvider.id,
+            query,
+            options: {
+              'limit': 5,
+              if (trackFilter != null) 'filter': trackFilter,
+            },
+          );
+        } else {
+          results = await PlatformBridge.searchTracksWithMetadataProvider(
+            selectedProvider!.id,
+            query,
+            limit: 5,
+          );
+        }
 
         if (!mounted) return;
 
@@ -1186,7 +1202,8 @@ class _EditMetadataSheetState extends State<_EditMetadataSheet> {
           coverUrl: coverUrl?.isNotEmpty == true ? coverUrl : null,
         );
       });
-    } catch (e) {
+    } catch (e, stackTrace) {
+      _log.e('Metadata auto-fill failed: $e', e, stackTrace);
       if (mounted) {
         _showSheetSnackBar(
           context.l10n.snackbarError(context.friendlyError(e)),