refactor: remove Qobuz built-in provider and delete qobuz.go

Delete the entire Qobuz downloader implementation (qobuz.go, qobuz_test.go)
including all API clients, search, metadata, download, and track matching
code. Empty the builtInProviderRegistry now that all built-in providers are
retired. Remove Qobuz-specific exports (SearchQobuzAll, GetQobuzMetadata,
ParseQobuzURLExport) and the downloadWithBuiltInQobuz adapter. Stub out
PreWarmTrackCache and cache management since no built-in providers remain.
Move qobuz cover upgrade regex to cover.go. Update Dart screens, providers,
and localization strings for the provider-agnostic UI.

lib/l10n/app_localizations.dart

@@ -376,10 +376,10 @@ abstract class AppLocalizations {
   /// **'Choose which tab opens first for new search results.'**
   String get optionsDefaultSearchTabSubtitle;
 
-  /// Hint to switch back to built-in providers
+  /// Hint to switch away from the current provider selection
   ///
   /// In en, this message translates to:
-  /// **'Tap Deezer or Spotify to switch back from extension'**
+  /// **'Choose another provider below to stop using the current extension'**
   String get optionsSwitchBack;
 
   /// Auto-retry with other services
@@ -406,10 +406,10 @@ abstract class AppLocalizations {
   /// **'Extensions will be tried first'**
   String get optionsUseExtensionProvidersOn;
 
-  /// Status when extension providers disabled
+  /// Status when extension providers are disabled
   ///
   /// In en, this message translates to:
-  /// **'Using built-in providers only'**
+  /// **'Extensions are turned off'**
   String get optionsUseExtensionProvidersOff;
 
   /// Embed lyrics in audio files
@@ -5073,16 +5073,16 @@ abstract class AppLocalizations {
   /// **'Off: strict HTTPS certificate validation (recommended)'**
   String get downloadNetworkCompatibilityModeDisabled;
 
-  /// Hint shown instead of Ask-quality subtitle when no built-in service selected
+  /// Hint shown instead of Ask-quality subtitle when the selected provider does not expose built-in quality controls
   ///
   /// In en, this message translates to:
-  /// **'Select a built-in service to enable'**
+  /// **'Select a compatible download provider to enable quality options'**
   String get downloadSelectServiceToEnable;
 
-  /// Info hint when non-Tidal/Qobuz service is selected
+  /// Info hint when the selected provider does not expose built-in quality controls
   ///
   /// In en, this message translates to:
-  /// **'Select Tidal or Qobuz above to configure quality'**
+  /// **'Select a compatible provider above to configure quality'**
   String get downloadSelectTidalQobuz;
 
   /// Subtitle for Embed Lyrics when Embed Metadata is disabled

lib/l10n/app_localizations_de.dart

@@ -2952,11 +2952,11 @@ class AppLocalizationsDe extends AppLocalizations {
 
   @override
   String get downloadSelectServiceToEnable =>
-      'Select a built-in service to enable';
+      'Select a compatible download provider to enable quality options';
 
   @override
   String get downloadSelectTidalQobuz =>
-      'Select Tidal or Qobuz above to configure quality';
+      'Select a compatible provider above to configure quality';
 
   @override
   String get downloadEmbedLyricsDisabled =>

lib/l10n/app_localizations_en.dart

@@ -143,7 +143,7 @@ class AppLocalizationsEn extends AppLocalizations {
 
   @override
   String get optionsSwitchBack =>
-      'Tap Deezer or Spotify to switch back from extension';
+      'Choose another provider below to stop using the current extension';
 
   @override
   String get optionsAutoFallback => 'Auto Fallback';
@@ -159,7 +159,7 @@ class AppLocalizationsEn extends AppLocalizations {
   String get optionsUseExtensionProvidersOn => 'Extensions will be tried first';
 
   @override
-  String get optionsUseExtensionProvidersOff => 'Using built-in providers only';
+  String get optionsUseExtensionProvidersOff => 'Extensions are turned off';
 
   @override
   String get optionsEmbedLyrics => 'Embed Lyrics';
@@ -2920,11 +2920,11 @@ class AppLocalizationsEn extends AppLocalizations {
 
   @override
   String get downloadSelectServiceToEnable =>
-      'Select a built-in service to enable';
+      'Select a compatible download provider to enable quality options';
 
   @override
   String get downloadSelectTidalQobuz =>
-      'Select Tidal or Qobuz above to configure quality';
+      'Select a compatible provider above to configure quality';
 
   @override
   String get downloadEmbedLyricsDisabled =>

lib/l10n/app_localizations_es.dart

@@ -2920,11 +2920,11 @@ class AppLocalizationsEs extends AppLocalizations {
 
   @override
   String get downloadSelectServiceToEnable =>
-      'Select a built-in service to enable';
+      'Select a compatible download provider to enable quality options';
 
   @override
   String get downloadSelectTidalQobuz =>
-      'Select Tidal or Qobuz above to configure quality';
+      'Select a compatible provider above to configure quality';
 
   @override
   String get downloadEmbedLyricsDisabled =>

lib/l10n/app_localizations_fr.dart

@@ -2921,11 +2921,11 @@ class AppLocalizationsFr extends AppLocalizations {
 
   @override
   String get downloadSelectServiceToEnable =>
-      'Select a built-in service to enable';
+      'Select a compatible download provider to enable quality options';
 
   @override
   String get downloadSelectTidalQobuz =>
-      'Select Tidal or Qobuz above to configure quality';
+      'Select a compatible provider above to configure quality';
 
   @override
   String get downloadEmbedLyricsDisabled =>

lib/l10n/app_localizations_hi.dart

@@ -2919,11 +2919,11 @@ class AppLocalizationsHi extends AppLocalizations {
 
   @override
   String get downloadSelectServiceToEnable =>
-      'Select a built-in service to enable';
+      'Select a compatible download provider to enable quality options';
 
   @override
   String get downloadSelectTidalQobuz =>
-      'Select Tidal or Qobuz above to configure quality';
+      'Select a compatible provider above to configure quality';
 
   @override
   String get downloadEmbedLyricsDisabled =>

lib/l10n/app_localizations_id.dart

@@ -145,7 +145,7 @@ class AppLocalizationsId extends AppLocalizations {
 
   @override
   String get optionsSwitchBack =>
-      'Ketuk Deezer atau Spotify untuk beralih dari ekstensi';
+      'Pilih provider lain di bawah untuk berhenti memakai ekstensi saat ini';
 
   @override
   String get optionsAutoFallback => 'Cadangan Otomatis';
@@ -162,8 +162,7 @@ class AppLocalizationsId extends AppLocalizations {
       'Ekstensi akan dicoba terlebih dahulu';
 
   @override
-  String get optionsUseExtensionProvidersOff =>
-      'Hanya menggunakan provider bawaan';
+  String get optionsUseExtensionProvidersOff => 'Ekstensi dimatikan';
 
   @override
   String get optionsEmbedLyrics => 'Sematkan Lirik';
@@ -2930,11 +2929,11 @@ class AppLocalizationsId extends AppLocalizations {
 
   @override
   String get downloadSelectServiceToEnable =>
-      'Select a built-in service to enable';
+      'Select a compatible download provider to enable quality options';
 
   @override
   String get downloadSelectTidalQobuz =>
-      'Select Tidal or Qobuz above to configure quality';
+      'Select a compatible provider above to configure quality';
 
   @override
   String get downloadEmbedLyricsDisabled =>

lib/l10n/app_localizations_ja.dart

@@ -142,8 +142,7 @@ class AppLocalizationsJa extends AppLocalizations {
       'Choose which tab opens first for new search results.';
 
   @override
-  String get optionsSwitchBack =>
-      'Tap Deezer or Spotify to switch back from extension';
+  String get optionsSwitchBack => '現在の拡張の使用をやめるには、下から別のプロバイダーを選択してください';
 
   @override
   String get optionsAutoFallback => 'Auto Fallback';
@@ -159,7 +158,7 @@ class AppLocalizationsJa extends AppLocalizations {
   String get optionsUseExtensionProvidersOn => '最初に拡張で試みます';
 
   @override
-  String get optionsUseExtensionProvidersOff => '内蔵のプロバイダーのみを使用する';
+  String get optionsUseExtensionProvidersOff => '拡張はオフです';
 
   @override
   String get optionsEmbedLyrics => '歌詞を埋め込む';
@@ -2906,11 +2905,11 @@ class AppLocalizationsJa extends AppLocalizations {
 
   @override
   String get downloadSelectServiceToEnable =>
-      'Select a built-in service to enable';
+      'Select a compatible download provider to enable quality options';
 
   @override
   String get downloadSelectTidalQobuz =>
-      'Select Tidal or Qobuz above to configure quality';
+      'Select a compatible provider above to configure quality';
 
   @override
   String get downloadEmbedLyricsDisabled =>

lib/l10n/app_localizations_ko.dart

@@ -2899,11 +2899,11 @@ class AppLocalizationsKo extends AppLocalizations {
 
   @override
   String get downloadSelectServiceToEnable =>
-      'Select a built-in service to enable';
+      'Select a compatible download provider to enable quality options';
 
   @override
   String get downloadSelectTidalQobuz =>
-      'Select Tidal or Qobuz above to configure quality';
+      'Select a compatible provider above to configure quality';
 
   @override
   String get downloadEmbedLyricsDisabled =>

lib/l10n/app_localizations_nl.dart

@@ -2919,11 +2919,11 @@ class AppLocalizationsNl extends AppLocalizations {
 
   @override
   String get downloadSelectServiceToEnable =>
-      'Select a built-in service to enable';
+      'Select a compatible download provider to enable quality options';
 
   @override
   String get downloadSelectTidalQobuz =>
-      'Select Tidal or Qobuz above to configure quality';
+      'Select a compatible provider above to configure quality';
 
   @override
   String get downloadEmbedLyricsDisabled =>

lib/l10n/app_localizations_pt.dart

@@ -2920,11 +2920,11 @@ class AppLocalizationsPt extends AppLocalizations {
 
   @override
   String get downloadSelectServiceToEnable =>
-      'Select a built-in service to enable';
+      'Select a compatible download provider to enable quality options';
 
   @override
   String get downloadSelectTidalQobuz =>
-      'Select Tidal or Qobuz above to configure quality';
+      'Select a compatible provider above to configure quality';
 
   @override
   String get downloadEmbedLyricsDisabled =>

lib/l10n/app_localizations_ru.dart

@@ -2979,11 +2979,11 @@ class AppLocalizationsRu extends AppLocalizations {
 
   @override
   String get downloadSelectServiceToEnable =>
-      'Select a built-in service to enable';
+      'Select a compatible download provider to enable quality options';
 
   @override
   String get downloadSelectTidalQobuz =>
-      'Select Tidal or Qobuz above to configure quality';
+      'Select a compatible provider above to configure quality';
 
   @override
   String get downloadEmbedLyricsDisabled =>

lib/l10n/app_localizations_tr.dart

@@ -146,7 +146,7 @@ class AppLocalizationsTr extends AppLocalizations {
 
   @override
   String get optionsSwitchBack =>
-      'Eklentiden çıkıp varsayılana dönmek için Deezer veya Spotify\'a dokunun';
+      'Geçerli eklentiyi bırakmak için aşağıdan başka bir sağlayıcı seçin';
 
   @override
   String get optionsAutoFallback => 'Otomatik Geçiş';
@@ -163,8 +163,7 @@ class AppLocalizationsTr extends AppLocalizations {
       'İndirme için önce eklentiler denenecek';
 
   @override
-  String get optionsUseExtensionProvidersOff =>
-      'Sadece yerleşik sağlayıcılar kullanılıyor';
+  String get optionsUseExtensionProvidersOff => 'Eklentiler kapalı';
 
   @override
   String get optionsEmbedLyrics => 'Şarkı Sözlerini Gömer';
@@ -2979,11 +2978,11 @@ class AppLocalizationsTr extends AppLocalizations {
 
   @override
   String get downloadSelectServiceToEnable =>
-      'Seçenekleri açmak için yerleşik bir sağlayıcı seçin';
+      'Kalite seçeneklerini açmak için uyumlu bir indirme sağlayıcısı seçin';
 
   @override
   String get downloadSelectTidalQobuz =>
-      'Kaliteyi ayarlamak için lütfen yukarıdan Tidal veya Qobuz seçin';
+      'Kaliteyi ayarlamak için yukarıdan uyumlu bir sağlayıcı seçin';
 
   @override
   String get downloadEmbedLyricsDisabled =>

lib/l10n/app_localizations_zh.dart

@@ -2920,11 +2920,11 @@ class AppLocalizationsZh extends AppLocalizations {
 
   @override
   String get downloadSelectServiceToEnable =>
-      'Select a built-in service to enable';
+      'Select a compatible download provider to enable quality options';
 
   @override
   String get downloadSelectTidalQobuz =>
-      'Select Tidal or Qobuz above to configure quality';
+      'Select a compatible provider above to configure quality';
 
   @override
   String get downloadEmbedLyricsDisabled =>

lib/l10n/arb/app_en.arb

@@ -174,9 +174,9 @@
   "@optionsDefaultSearchTabSubtitle": {
     "description": "Subtitle for the preferred default search tab setting"
   },
-  "optionsSwitchBack": "Tap Deezer or Spotify to switch back from extension",
+  "optionsSwitchBack": "Choose another provider below to stop using the current extension",
   "@optionsSwitchBack": {
-    "description": "Hint to switch back to built-in providers"
+    "description": "Hint to switch away from the current provider selection"
   },
   "optionsAutoFallback": "Auto Fallback",
   "@optionsAutoFallback": {
@@ -194,9 +194,9 @@
   "@optionsUseExtensionProvidersOn": {
     "description": "Status when extension providers enabled"
   },
-  "optionsUseExtensionProvidersOff": "Using built-in providers only",
+  "optionsUseExtensionProvidersOff": "Extensions are turned off",
   "@optionsUseExtensionProvidersOff": {
-    "description": "Status when extension providers disabled"
+    "description": "Status when extension providers are disabled"
   },
   "optionsEmbedLyrics": "Embed Lyrics",
   "@optionsEmbedLyrics": {
@@ -3867,14 +3867,14 @@
   "@downloadNetworkCompatibilityModeDisabled": {
     "description": "Subtitle when network compatibility mode is disabled"
   },
-  "downloadSelectServiceToEnable": "Select a built-in service to enable",
+  "downloadSelectServiceToEnable": "Select a compatible download provider to enable quality options",
   "@downloadSelectServiceToEnable": {
-    "description": "Hint shown instead of Ask-quality subtitle when no built-in service selected"
+    "description": "Hint shown instead of Ask-quality subtitle when the selected provider does not expose built-in quality controls"
   },
 
-  "downloadSelectTidalQobuz": "Select Tidal or Qobuz above to configure quality",
+  "downloadSelectTidalQobuz": "Select a compatible provider above to configure quality",
   "@downloadSelectTidalQobuz": {
-    "description": "Info hint when non-Tidal/Qobuz service is selected"
+    "description": "Info hint when the selected provider does not expose built-in quality controls"
   },
   "downloadEmbedLyricsDisabled": "Disabled while Embed Metadata is turned off",
   "@downloadEmbedLyricsDisabled": {

lib/l10n/arb/app_id.arb

@@ -158,9 +158,9 @@
   "@optionsDefaultSearchTabSubtitle": {
     "description": "Subtitle for the preferred default search tab setting"
   },
-  "optionsSwitchBack": "Ketuk Deezer atau Spotify untuk beralih dari ekstensi",
+  "optionsSwitchBack": "Pilih provider lain di bawah untuk berhenti memakai ekstensi saat ini",
   "@optionsSwitchBack": {
-    "description": "Hint to switch back to built-in providers"
+    "description": "Hint to switch away from the current provider selection"
   },
   "optionsAutoFallback": "Cadangan Otomatis",
   "@optionsAutoFallback": {
@@ -178,9 +178,9 @@
   "@optionsUseExtensionProvidersOn": {
     "description": "Status when extension providers enabled"
   },
-  "optionsUseExtensionProvidersOff": "Hanya menggunakan provider bawaan",
+  "optionsUseExtensionProvidersOff": "Ekstensi dimatikan",
   "@optionsUseExtensionProvidersOff": {
-    "description": "Status when extension providers disabled"
+    "description": "Status when extension providers are disabled"
   },
   "optionsEmbedLyrics": "Sematkan Lirik",
   "@optionsEmbedLyrics": {

lib/l10n/arb/app_ja.arb

@@ -150,9 +150,9 @@
       }
     }
   },
-  "optionsSwitchBack": "Tap Deezer or Spotify to switch back from extension",
+  "optionsSwitchBack": "現在の拡張の使用をやめるには、下から別のプロバイダーを選択してください",
   "@optionsSwitchBack": {
-    "description": "Hint to switch back to built-in providers"
+    "description": "Hint to switch away from the current provider selection"
   },
   "optionsAutoFallback": "Auto Fallback",
   "@optionsAutoFallback": {
@@ -170,9 +170,9 @@
   "@optionsUseExtensionProvidersOn": {
     "description": "Status when extension providers enabled"
   },
-  "optionsUseExtensionProvidersOff": "内蔵のプロバイダーのみを使用する",
+  "optionsUseExtensionProvidersOff": "拡張はオフです",
   "@optionsUseExtensionProvidersOff": {
-    "description": "Status when extension providers disabled"
+    "description": "Status when extension providers are disabled"
   },
   "optionsEmbedLyrics": "歌詞を埋め込む",
   "@optionsEmbedLyrics": {
@@ -3198,4 +3198,4 @@
   "@downloadUseAlbumArtistForFoldersTrackSubtitle": {
     "description": "Subtitle when Track Artist is used for folder naming"
   }
-}
+}

lib/l10n/arb/app_tr.arb

@@ -150,9 +150,9 @@
       }
     }
   },
-  "optionsSwitchBack": "Eklentiden çıkıp varsayılana dönmek için Deezer veya Spotify'a dokunun",
+  "optionsSwitchBack": "Geçerli eklentiyi bırakmak için aşağıdan başka bir sağlayıcı seçin",
   "@optionsSwitchBack": {
-    "description": "Hint to switch back to built-in providers"
+    "description": "Hint to switch away from the current provider selection"
   },
   "optionsAutoFallback": "Otomatik Geçiş",
   "@optionsAutoFallback": {
@@ -170,9 +170,9 @@
   "@optionsUseExtensionProvidersOn": {
     "description": "Status when extension providers enabled"
   },
-  "optionsUseExtensionProvidersOff": "Sadece yerleşik sağlayıcılar kullanılıyor",
+  "optionsUseExtensionProvidersOff": "Eklentiler kapalı",
   "@optionsUseExtensionProvidersOff": {
-    "description": "Status when extension providers disabled"
+    "description": "Status when extension providers are disabled"
   },
   "optionsEmbedLyrics": "Şarkı Sözlerini Gömer",
   "@optionsEmbedLyrics": {
@@ -3689,13 +3689,13 @@
   "@downloadNetworkCompatibilityModeDisabled": {
     "description": "Subtitle when network compatibility mode is disabled"
   },
-  "downloadSelectServiceToEnable": "Seçenekleri açmak için yerleşik bir sağlayıcı seçin",
+  "downloadSelectServiceToEnable": "Kalite seçeneklerini açmak için uyumlu bir indirme sağlayıcısı seçin",
   "@downloadSelectServiceToEnable": {
-    "description": "Hint shown instead of Ask-quality subtitle when no built-in service selected"
+    "description": "Hint shown instead of Ask-quality subtitle when the selected provider does not expose built-in quality controls"
   },
-  "downloadSelectTidalQobuz": "Kaliteyi ayarlamak için lütfen yukarıdan Tidal veya Qobuz seçin",
+  "downloadSelectTidalQobuz": "Kaliteyi ayarlamak için yukarıdan uyumlu bir sağlayıcı seçin",
   "@downloadSelectTidalQobuz": {
-    "description": "Info hint when non-Tidal/Qobuz service is selected"
+    "description": "Info hint when the selected provider does not expose built-in quality controls"
   },
   "downloadEmbedLyricsDisabled": "Şarkı Verilerini Dosyaya Gömme ayarı kapalıyken kullanılamaz",
   "@downloadEmbedLyricsDisabled": {

lib/providers/download_queue_provider.dart

@@ -4815,7 +4815,7 @@ class DownloadQueueNotifier extends Notifier<DownloadQueueState> {
         String payloadTidalId = '';
         if (trackToDownload.id.startsWith('qobuz:')) {
           payloadQobuzId = trackToDownload.id.substring(6);
-          if (item.service == 'qobuz') {
+          if (_usesBuiltInCompatibleDownloadProvider(item.service, 'qobuz')) {
             payloadSpotifyId = '';
           }
         }

lib/providers/extension_provider.dart

@@ -288,6 +288,85 @@ List<String> get builtInDownloadProviderIds => List<String>.unmodifiable(
   builtInDownloadProviderSpecs.map((provider) => provider.id),
 );
 
+String resolveEffectiveDownloadService(
+  String requestedService,
+  ExtensionState extensionState,
+) {
+  final normalizedRequested = requestedService.trim().toLowerCase();
+  final builtInDownloadIds = extensionState.builtInProviders
+      .where((provider) => provider.supportsDownload)
+      .map((provider) => provider.id.trim().toLowerCase())
+      .where((providerId) => providerId.isNotEmpty)
+      .toSet();
+  final enabledDownloadExtensions = extensionState.extensions
+      .where((ext) => ext.enabled && ext.hasDownloadProvider)
+      .toList(growable: false);
+
+  if (normalizedRequested.isNotEmpty) {
+    if (builtInDownloadIds.contains(normalizedRequested)) {
+      return normalizedRequested;
+    }
+
+    final matchingExtension = enabledDownloadExtensions
+        .where((ext) => ext.id.trim().toLowerCase() == normalizedRequested)
+        .firstOrNull;
+    if (matchingExtension != null) {
+      return matchingExtension.id;
+    }
+
+    final replacementExtension = enabledDownloadExtensions
+        .where(
+          (ext) => ext.replacesBuiltInProviders.contains(normalizedRequested),
+        )
+        .firstOrNull;
+    if (replacementExtension != null) {
+      return replacementExtension.id;
+    }
+  }
+
+  const preferredBuiltInOrder = ['tidal', 'qobuz', 'deezer'];
+  for (final builtInId in preferredBuiltInOrder) {
+    final replacement = enabledDownloadExtensions
+        .where((ext) => ext.replacesBuiltInProviders.contains(builtInId))
+        .firstOrNull;
+    if (replacement != null) {
+      return replacement.id;
+    }
+    if (builtInDownloadIds.contains(builtInId)) {
+      return builtInId;
+    }
+  }
+
+  return enabledDownloadExtensions.firstOrNull?.id ??
+      extensionState.builtInProviders
+          .where((provider) => provider.supportsDownload)
+          .map((provider) => provider.id)
+          .firstOrNull ??
+      '';
+}
+
+bool isDeezerCompatibleDownloadService(
+  String service,
+  ExtensionState extensionState,
+) {
+  final normalizedService = service.trim().toLowerCase();
+  if (normalizedService.isEmpty) {
+    return false;
+  }
+
+  if (normalizedService == 'deezer') {
+    return true;
+  }
+
+  return extensionState.extensions.any(
+    (ext) =>
+        ext.enabled &&
+        ext.hasDownloadProvider &&
+        ext.id.trim().toLowerCase() == normalizedService &&
+        ext.replacesBuiltInProviders.contains('deezer'),
+  );
+}
+
 bool isBuiltInSearchProvider(String? providerId) =>
     builtInProviderSpecForId(providerId)?.supportsSearch ?? false;
 

lib/providers/track_provider.dart

@@ -599,7 +599,6 @@ class TrackNotifier extends Notifier<TrackState> {
     if (effectiveBuiltInProvider == null || effectiveBuiltInProvider.isEmpty) {
       state = TrackState(
         isLoading: false,
-        error: 'No active search provider available',
         hasSearchText: state.hasSearchText,
         isShowingRecentAccess: state.isShowingRecentAccess,
         selectedSearchFilter: currentFilter,

lib/screens/album_screen.dart

@@ -5,6 +5,7 @@ import 'package:spotiflac_android/services/cover_cache_manager.dart';
 import 'package:spotiflac_android/l10n/l10n.dart';
 import 'package:spotiflac_android/models/track.dart';
 import 'package:spotiflac_android/providers/download_queue_provider.dart';
+import 'package:spotiflac_android/providers/extension_provider.dart';
 import 'package:spotiflac_android/providers/settings_provider.dart';
 import 'package:spotiflac_android/providers/recent_access_provider.dart';
 import 'package:spotiflac_android/providers/local_library_provider.dart';
@@ -644,9 +645,20 @@ class _AlbumScreenState extends ConsumerState<AlbumScreen> {
         },
       );
     } else {
+      final extensionState = ref.read(extensionProvider);
+      final service = resolveEffectiveDownloadService(
+        settings.defaultService,
+        extensionState,
+      );
+      if (service.isEmpty) {
+        ScaffoldMessenger.of(context).showSnackBar(
+          SnackBar(content: Text(context.l10n.extensionsNoDownloadProvider)),
+        );
+        return;
+      }
       ref
           .read(downloadQueueProvider.notifier)
-          .addToQueue(track, settings.defaultService);
+          .addToQueue(track, service);
       ScaffoldMessenger.of(context).showSnackBar(
         SnackBar(content: Text(context.l10n.snackbarAddedToQueue(track.name))),
       );
@@ -716,9 +728,20 @@ class _AlbumScreenState extends ConsumerState<AlbumScreen> {
         },
       );
     } else {
+      final extensionState = ref.read(extensionProvider);
+      final service = resolveEffectiveDownloadService(
+        settings.defaultService,
+        extensionState,
+      );
+      if (service.isEmpty) {
+        ScaffoldMessenger.of(context).showSnackBar(
+          SnackBar(content: Text(context.l10n.extensionsNoDownloadProvider)),
+        );
+        return;
+      }
       ref
           .read(downloadQueueProvider.notifier)
-          .addMultipleToQueue(tracksToQueue, settings.defaultService);
+          .addMultipleToQueue(tracksToQueue, service);
       _showQueuedSnackbar(context, tracksToQueue.length, skippedCount);
     }
   }

lib/screens/artist_screen.dart

@@ -6,6 +6,7 @@ import 'package:intl/intl.dart';
 import 'package:spotiflac_android/services/cover_cache_manager.dart';
 import 'package:spotiflac_android/l10n/l10n.dart';
 import 'package:spotiflac_android/models/track.dart';
+import 'package:spotiflac_android/providers/extension_provider.dart';
 import 'package:spotiflac_android/providers/track_provider.dart';
 import 'package:spotiflac_android/providers/settings_provider.dart';
 import 'package:spotiflac_android/providers/download_queue_provider.dart';
@@ -1627,7 +1628,18 @@ class _ArtistScreenState extends ConsumerState<ArtistScreen> {
       return;
     }
 
-    enqueue(settings.defaultService);
+    final extensionState = ref.read(extensionProvider);
+    final service = resolveEffectiveDownloadService(
+      settings.defaultService,
+      extensionState,
+    );
+    if (service.isEmpty) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(content: Text(context.l10n.extensionsNoDownloadProvider)),
+      );
+      return;
+    }
+    enqueue(service);
   }
 
   Widget _buildAlbumSection(

lib/screens/home_tab.dart

@@ -1004,9 +1004,20 @@ class _HomeTabState extends ConsumerState<HomeTab>
           },
         );
       } else {
+        final extensionState = ref.read(extensionProvider);
+        final service = resolveEffectiveDownloadService(
+          settings.defaultService,
+          extensionState,
+        );
+        if (service.isEmpty) {
+          ScaffoldMessenger.of(context).showSnackBar(
+            SnackBar(content: Text(context.l10n.extensionsNoDownloadProvider)),
+          );
+          return;
+        }
         ref
             .read(downloadQueueProvider.notifier)
-            .addToQueue(track, settings.defaultService);
+            .addToQueue(track, service);
         ScaffoldMessenger.of(context).showSnackBar(
           SnackBar(
             content: Text(context.l10n.snackbarAddedToQueue(track.name)),
@@ -1227,9 +1238,24 @@ class _HomeTabState extends ConsumerState<HomeTab>
             },
           );
         } else {
+          final extensionState = ref.read(extensionProvider);
+          final service = resolveEffectiveDownloadService(
+            settings.defaultService,
+            extensionState,
+          );
+          if (service.isEmpty) {
+            if (mounted) {
+              ScaffoldMessenger.of(this.context).showSnackBar(
+                SnackBar(
+                  content: Text(this.context.l10n.extensionsNoDownloadProvider),
+                ),
+              );
+            }
+            return;
+          }
           ref
               .read(downloadQueueProvider.notifier)
-              .addMultipleToQueue(tracksToQueue, settings.defaultService);
+              .addMultipleToQueue(tracksToQueue, service);
           if (mounted) {
             ScaffoldMessenger.of(this.context).showSnackBar(
               SnackBar(
@@ -2139,9 +2165,20 @@ class _HomeTabState extends ConsumerState<HomeTab>
         },
       );
     } else {
+      final extensionState = ref.read(extensionProvider);
+      final service = resolveEffectiveDownloadService(
+        settings.defaultService,
+        extensionState,
+      );
+      if (service.isEmpty) {
+        ScaffoldMessenger.of(context).showSnackBar(
+          SnackBar(content: Text(context.l10n.extensionsNoDownloadProvider)),
+        );
+        return;
+      }
       ref
           .read(downloadQueueProvider.notifier)
-          .addToQueue(track, settings.defaultService);
+          .addToQueue(track, service);
       ScaffoldMessenger.of(context).showSnackBar(
         SnackBar(content: Text(context.l10n.snackbarAddedToQueue(track.name))),
       );

lib/screens/library_tracks_folder_screen.dart

@@ -8,6 +8,7 @@ import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:spotiflac_android/l10n/l10n.dart';
 import 'package:spotiflac_android/models/track.dart';
 import 'package:spotiflac_android/providers/download_queue_provider.dart';
+import 'package:spotiflac_android/providers/extension_provider.dart';
 import 'package:spotiflac_android/providers/library_collections_provider.dart';
 import 'package:spotiflac_android/providers/playback_provider.dart';
 import 'package:spotiflac_android/providers/local_library_provider.dart';
@@ -214,12 +215,23 @@ class _LibraryTracksFolderScreenState
 
   void _downloadSelected(List<CollectionTrackEntry> entries) {
     final settings = ref.read(settingsProvider);
+    final extensionState = ref.read(extensionProvider);
+    final service = resolveEffectiveDownloadService(
+      settings.defaultService,
+      extensionState,
+    );
+    if (service.isEmpty) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(content: Text(context.l10n.extensionsNoDownloadProvider)),
+      );
+      return;
+    }
     final queueNotifier = ref.read(downloadQueueProvider.notifier);
     var count = 0;
 
     for (final entry in entries) {
       if (!_selectedKeys.contains(entry.key)) continue;
-      queueNotifier.addToQueue(entry.track, settings.defaultService);
+      queueNotifier.addToQueue(entry.track, service);
       count++;
     }
 
@@ -1349,9 +1361,20 @@ class _CollectionTrackTile extends ConsumerWidget {
         },
       );
     } else {
+      final extensionState = ref.read(extensionProvider);
+      final service = resolveEffectiveDownloadService(
+        settings.defaultService,
+        extensionState,
+      );
+      if (service.isEmpty) {
+        ScaffoldMessenger.of(context).showSnackBar(
+          SnackBar(content: Text(context.l10n.extensionsNoDownloadProvider)),
+        );
+        return;
+      }
       ref
           .read(downloadQueueProvider.notifier)
-          .addToQueue(track, settings.defaultService);
+          .addToQueue(track, service);
       ScaffoldMessenger.of(context).showSnackBar(
         SnackBar(content: Text(context.l10n.snackbarAddedToQueue(track.name))),
       );

lib/screens/local_album_screen.dart

@@ -965,10 +965,18 @@ class _LocalAlbumScreenState extends ConsumerState<LocalAlbumScreen> {
         );
     final targetService = LocalTrackRedownloadService.preferredFlacService(
       settings,
+      extensionState,
     );
+    if (targetService.isEmpty) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(content: Text(context.l10n.extensionsNoDownloadProvider)),
+      );
+      return;
+    }
     final targetQuality =
         LocalTrackRedownloadService.preferredFlacQualityForService(
           targetService,
+          extensionState,
         );
 
     final matchedTracks = <Track>[];

lib/screens/playlist_screen.dart

@@ -6,6 +6,7 @@ import 'package:spotiflac_android/services/platform_bridge.dart';
 import 'package:spotiflac_android/l10n/l10n.dart';
 import 'package:spotiflac_android/models/track.dart';
 import 'package:spotiflac_android/providers/download_queue_provider.dart';
+import 'package:spotiflac_android/providers/extension_provider.dart';
 import 'package:spotiflac_android/providers/library_collections_provider.dart';
 import 'package:spotiflac_android/utils/file_access.dart';
 import 'package:spotiflac_android/utils/image_cache_utils.dart';
@@ -495,11 +496,22 @@ class _PlaylistScreenState extends ConsumerState<PlaylistScreen> {
         },
       );
     } else {
+      final extensionState = ref.read(extensionProvider);
+      final service = resolveEffectiveDownloadService(
+        settings.defaultService,
+        extensionState,
+      );
+      if (service.isEmpty) {
+        ScaffoldMessenger.of(context).showSnackBar(
+          SnackBar(content: Text(context.l10n.extensionsNoDownloadProvider)),
+        );
+        return;
+      }
       ref
           .read(downloadQueueProvider.notifier)
           .addToQueue(
             track,
-            settings.defaultService,
+            service,
             playlistName: _playlistName,
           );
       ScaffoldMessenger.of(context).showSnackBar(

lib/screens/queue_tab.dart

@@ -1845,10 +1845,24 @@ class _QueueTabState extends ConsumerState<QueueTab> {
     if (confirmed != true || !context.mounted) return;
 
     final settings = ref.read(settingsProvider);
+    final extensionState = ref.read(extensionProvider);
     final queueNotifier = ref.read(downloadQueueProvider.notifier);
 
     void enqueueAll({String? qualityOverride, String? service}) {
-      final svc = service ?? settings.defaultService;
+      final svc =
+          service ??
+          resolveEffectiveDownloadService(
+            settings.defaultService,
+            extensionState,
+          );
+      if (svc.isEmpty) {
+        if (mounted) {
+          ScaffoldMessenger.of(context).showSnackBar(
+            SnackBar(content: Text(context.l10n.extensionsNoDownloadProvider)),
+          );
+        }
+        return;
+      }
       for (final playlist in selectedPlaylists) {
         final tracks = playlist.tracks.map((e) => e.track).toList();
         queueNotifier.addMultipleToQueue(
@@ -5218,10 +5232,18 @@ class _QueueTabState extends ConsumerState<QueueTab> {
         );
     final targetService = LocalTrackRedownloadService.preferredFlacService(
       settings,
+      extensionState,
     );
+    if (targetService.isEmpty) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(content: Text(context.l10n.extensionsNoDownloadProvider)),
+      );
+      return;
+    }
     final targetQuality =
         LocalTrackRedownloadService.preferredFlacQualityForService(
           targetService,
+          extensionState,
         );
 
     final matchedTracks = <Track>[];

lib/screens/search_screen.dart

@@ -4,6 +4,7 @@ import 'package:cached_network_image/cached_network_image.dart';
 import 'package:spotiflac_android/l10n/l10n.dart';
 import 'package:spotiflac_android/services/cover_cache_manager.dart';
 import 'package:spotiflac_android/models/track.dart';
+import 'package:spotiflac_android/providers/extension_provider.dart';
 import 'package:spotiflac_android/providers/track_provider.dart';
 import 'package:spotiflac_android/providers/download_queue_provider.dart';
 import 'package:spotiflac_android/providers/settings_provider.dart';
@@ -49,9 +50,20 @@ class _SearchScreenState extends ConsumerState<SearchScreen> {
 
   void _downloadTrack(Track track) {
     final settings = ref.read(settingsProvider);
+    final extensionState = ref.read(extensionProvider);
+    final service = resolveEffectiveDownloadService(
+      settings.defaultService,
+      extensionState,
+    );
+    if (service.isEmpty) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(content: Text(context.l10n.extensionsNoDownloadProvider)),
+      );
+      return;
+    }
     ref
         .read(downloadQueueProvider.notifier)
-        .addToQueue(track, settings.defaultService);
+        .addToQueue(track, service);
     ScaffoldMessenger.of(context).showSnackBar(
       SnackBar(content: Text(context.l10n.snackbarAddedToQueue(track.name))),
     );

lib/services/local_track_redownload_service.dart

@@ -1,5 +1,6 @@
 import 'package:spotiflac_android/models/settings.dart';
 import 'package:spotiflac_android/models/track.dart';
+import 'package:spotiflac_android/providers/extension_provider.dart';
 import 'package:spotiflac_android/services/library_database.dart';
 import 'package:spotiflac_android/services/platform_bridge.dart';
 
@@ -101,19 +102,26 @@ class LocalTrackRedownloadService {
     );
   }
 
-  static String preferredFlacService(AppSettings settings) {
-    switch (settings.defaultService.toLowerCase()) {
-      case 'tidal':
-      case 'qobuz':
-      case 'deezer':
-        return settings.defaultService.toLowerCase();
-      default:
-        return '';
-    }
+  static String preferredFlacService(
+    AppSettings settings,
+    ExtensionState extensionState,
+  ) {
+    return resolveEffectiveDownloadService(
+      settings.defaultService,
+      extensionState,
+    );
   }
 
-  static String preferredFlacQualityForService(String service) {
-    return service.toLowerCase() == 'deezer' ? 'FLAC' : 'LOSSLESS';
+  static String preferredFlacQualityForService(
+    String service,
+    ExtensionState extensionState,
+  ) {
+    if (service.trim().isEmpty) {
+      return 'LOSSLESS';
+    }
+    return isDeezerCompatibleDownloadService(service, extensionState)
+        ? 'FLAC'
+        : 'LOSSLESS';
   }
 
   static String _buildSearchQuery(LocalLibraryItem item) {