Wire Discogs as fully featured fallback metadata source

- SpotifyClient: add _discogs lazy-load property, route _fallback to
  DiscogsClient when configured (requires token, falls back to iTunes)
- web_server: _get_metadata_fallback_client returns DiscogsClient when
  selected and token present
- Enhanced search: Discogs added as source tab with NDJSON streaming,
  only available when token configured
- Alternate sources list includes Discogs when token is set
- Frontend: source labels, tab styling, fetch list all include Discogs
- Consistent with iTunes/Deezer pattern — same interfaces, same routing

core/spotify_client.py

@@ -417,6 +417,7 @@ class SpotifyClient:
         self.user_id: Optional[str] = None
         self._itunes_client = None  # Lazy-loaded iTunes fallback
         self._deezer_client = None  # Lazy-loaded Deezer fallback
+        self._discogs_client = None  # Lazy-loaded Discogs fallback
         self._auth_cache_lock = threading.Lock()
         self._auth_cached_result: Optional[bool] = None
         self._auth_cache_time: float = 0
@@ -454,9 +455,18 @@ class SpotifyClient:
             logger.info("Deezer fallback client initialized")
         return self._deezer_client
 
+    @property
+    def _discogs(self):
+        """Lazy-load Discogs client for metadata fallback"""
+        if self._discogs_client is None:
+            from core.discogs_client import DiscogsClient
+            self._discogs_client = DiscogsClient()
+            logger.info("Discogs fallback client initialized")
+        return self._discogs_client
+
     @property
     def _fallback_source(self) -> str:
-        """Get configured metadata fallback source ('itunes' or 'deezer')"""
+        """Get configured metadata fallback source ('itunes', 'deezer', or 'discogs')"""
         try:
             return config_manager.get('metadata.fallback_source', 'itunes') or 'itunes'
         except Exception:
@@ -467,6 +477,12 @@ class SpotifyClient:
         """Get the active fallback metadata client based on settings"""
         if self._fallback_source == 'deezer':
             return self._deezer
+        if self._fallback_source == 'discogs':
+            # Only use Discogs if token is configured
+            token = config_manager.get('discogs.token', '')
+            if token:
+                return self._discogs
+            return self._itunes  # Fall back to iTunes if no Discogs token
         return self._itunes
 
     def reload_config(self):

web_server.py

@@ -7362,6 +7362,7 @@ def enhanced_search():
         # Determine which alternate sources are available (for frontend to fetch async)
         spotify_available = bool(spotify_client and spotify_client.is_spotify_authenticated())
         hydrabase_available = bool(hydrabase_client and hydrabase_client.is_connected())
+        discogs_available = bool(config_manager.get('discogs.token', ''))
         alternate_sources = []
         if primary_source != 'spotify' and spotify_available:
             alternate_sources.append('spotify')
@@ -7369,6 +7370,8 @@ def enhanced_search():
             alternate_sources.append('itunes')
         if primary_source != 'deezer':
             alternate_sources.append('deezer')
+        if primary_source != 'discogs' and discogs_available:
+            alternate_sources.append('discogs')
         if primary_source != 'hydrabase' and hydrabase_available:
             alternate_sources.append('hydrabase')
 
@@ -7457,7 +7460,7 @@ def enhanced_search_source(source_name):
     This prevents slow sources (iTunes with 3s rate limit) from blocking the UI.
     Falls back to single JSON response if streaming not supported.
     """
-    if source_name not in ('spotify', 'itunes', 'deezer', 'hydrabase'):
+    if source_name not in ('spotify', 'itunes', 'deezer', 'discogs', 'hydrabase'):
         return jsonify({"error": f"Unknown source: {source_name}"}), 400
 
     data = request.get_json()
@@ -7477,6 +7480,13 @@ def enhanced_search_source(source_name):
             client = iTunesClient()
         elif source_name == 'deezer':
             client = _get_deezer_client()
+        elif source_name == 'discogs':
+            token = config_manager.get('discogs.token', '')
+            if token:
+                from core.discogs_client import DiscogsClient
+                client = DiscogsClient(token=token)
+            else:
+                return jsonify({"artists": [], "albums": [], "tracks": [], "available": False})
         elif source_name == 'hydrabase':
             if hydrabase_client and hydrabase_client.is_connected():
                 client = hydrabase_client
@@ -31896,7 +31906,7 @@ def _get_deezer_client():
     return _deezer_client_instance
 
 def _get_metadata_fallback_source():
-    """Get the configured metadata fallback source ('itunes', 'deezer', or 'hydrabase')."""
+    """Get the configured metadata fallback source ('itunes', 'deezer', 'discogs', or 'hydrabase')."""
     try:
         return config_manager.get('metadata.fallback_source', 'deezer') or 'deezer'
     except Exception:
@@ -31904,14 +31914,21 @@ def _get_metadata_fallback_source():
 
 def _get_metadata_fallback_client():
     """Get the active metadata fallback client based on settings.
-    Returns an iTunesClient, DeezerClient, or HydrabaseClient instance with identical interfaces."""
+    Returns an iTunesClient, DeezerClient, DiscogsClient, or HydrabaseClient instance with identical interfaces."""
     source = _get_metadata_fallback_source()
     if source == 'deezer':
         return _get_deezer_client()
+    if source == 'discogs':
+        token = config_manager.get('discogs.token', '')
+        if token:
+            from core.discogs_client import DiscogsClient
+            return DiscogsClient(token=token)
+        # No token — fall back to iTunes
+        from core.itunes_client import iTunesClient
+        return iTunesClient()
     if source == 'hydrabase':
         if hydrabase_client and hydrabase_client.is_connected():
             return hydrabase_client
-        # Hydrabase not connected — fall back to iTunes
         from core.itunes_client import iTunesClient
         return iTunesClient()
     from core.itunes_client import iTunesClient

webui/static/script.js

@@ -7922,6 +7922,7 @@ function initializeSearchModeToggle() {
         spotify: { text: 'Spotify', tabClass: 'enh-tab-spotify', badgeClass: 'enh-badge-spotify' },
         itunes: { text: 'Apple Music', tabClass: 'enh-tab-itunes', badgeClass: 'enh-badge-itunes' },
         deezer: { text: 'Deezer', tabClass: 'enh-tab-deezer', badgeClass: 'enh-badge-deezer' },
+        discogs: { text: 'Discogs', tabClass: 'enh-tab-discogs', badgeClass: 'enh-badge-discogs' },
         hydrabase: { text: 'Hydrabase', tabClass: 'enh-tab-hydrabase', badgeClass: 'enh-badge-hydrabase' },
     };
 
@@ -8047,7 +8048,7 @@ function initializeSearchModeToggle() {
         // Fire ALL source fetches immediately in parallel with the primary endpoint.
         // Don't guess which is primary — the main endpoint response will tell us.
         // If an alternate duplicates the primary, it just overwrites with same data.
-        for (const srcName of ['spotify', 'itunes', 'deezer', 'hydrabase']) {
+        for (const srcName of ['spotify', 'itunes', 'deezer', 'discogs', 'hydrabase']) {
             _fetchAlternateSource(srcName, query);
         }
 
@@ -17120,7 +17121,7 @@ function _gsRender(data) {
         return;
     }
 
-    const sourceLabels = { spotify: 'Spotify', itunes: 'Apple Music', deezer: 'Deezer', hydrabase: 'Hydrabase' };
+    const sourceLabels = { spotify: 'Spotify', itunes: 'Apple Music', deezer: 'Deezer', discogs: 'Discogs', hydrabase: 'Hydrabase' };
     const srcLabel = sourceLabels[_gsState.activeSource] || _gsState.activeSource || '';
 
     let h = '';
@@ -17217,7 +17218,7 @@ function _gsRenderTabs() {
     if (!el) return;
     const sources = Object.keys(_gsState.sources);
     if (sources.length < 2) { el.style.display = 'none'; return; }
-    const labels = { spotify: 'Spotify', itunes: 'Apple Music', deezer: 'Deezer', hydrabase: 'Hydrabase' };
+    const labels = { spotify: 'Spotify', itunes: 'Apple Music', deezer: 'Deezer', discogs: 'Discogs', hydrabase: 'Hydrabase' };
     el.style.display = 'flex';
     el.innerHTML = sources.map(s => {
         const d = _gsState.sources[s];
@@ -44811,7 +44812,7 @@ function _renderRedownloadStep1(overlay, track, data) {
 
     const bestSource = data.best_match?.source || sources[0];
     const sourceIcons = { spotify: '🟢', itunes: '🍎', deezer: '🟣', hydrabase: '🔷' };
-    const sourceLabels = { spotify: 'Spotify', itunes: 'Apple Music', deezer: 'Deezer', hydrabase: 'Hydrabase' };
+    const sourceLabels = { spotify: 'Spotify', itunes: 'Apple Music', deezer: 'Deezer', discogs: 'Discogs', hydrabase: 'Hydrabase' };
 
     // Build columns — one per source, side by side
     const columnsHtml = sources.map(source => {

webui/static/style.css

@@ -32143,6 +32143,7 @@ body.helper-mode-active #dashboard-activity-feed:hover {
 .enh-source-tab.enh-tab-spotify.active { background: rgba(29, 185, 84, 0.2); color: #1db954; }
 .enh-source-tab.enh-tab-itunes.active { background: rgba(252, 60, 68, 0.2); color: #fc3c44; }
 .enh-source-tab.enh-tab-deezer.active { background: rgba(162, 56, 255, 0.2); color: #a238ff; }
+.enh-source-tab.enh-tab-discogs.active { background: rgba(212, 165, 116, 0.2); color: #D4A574; }
 .enh-source-tab.enh-tab-hydrabase.active { background: rgba(0, 180, 216, 0.2); color: #00b4d8; }
 
 .enh-dropdown-section {