documentation and env changes

src/Service/SpotifyClient.php

@@ -24,8 +24,8 @@ class SpotifyClient
     public function __construct(
         HttpClientInterface $httpClient,
         CacheInterface $cache,
-        string $clientId,
-        string $clientSecret,
+        ?string $clientId,
+        ?string $clientSecret,
         SettingRepository $settings
     ) {
         $this->httpClient = $httpClient;
@@ -129,6 +129,8 @@ class SpotifyClient
             $offset += $limit;
             $total = isset($page['total']) ? (int) $page['total'] : null;
             $hasNext = isset($page['next']) && $page['next'] !== null;
+            // Guard against Spotify omitting total by relying on the "next" cursor.
+            // Ensures album requests stop when Spotify has no more pages.
         } while ($hasNext && ($total === null || $offset < $total));
 
         return $items;
@@ -197,6 +199,7 @@ class SpotifyClient
 
         $shouldCache = $cacheTtlSeconds > 0 && strtoupper($method) === 'GET';
         if ($shouldCache) {
+            // Cache fingerprint mixes URL and query only; headers are static (Bearer token).
             $cacheKey = 'spotify_resp_' . sha1($url . '|' . json_encode($options['query'] ?? []));
             return $this->cache->get($cacheKey, function (ItemInterface $item) use ($cacheTtlSeconds, $request) {
                 $item->expiresAfter($cacheTtlSeconds);
@@ -268,12 +271,22 @@ class SpotifyClient
         });
 
         if ($token === null) {
-            // Remove failed entries so the next request retries instead of serving cached nulls.
+            // Nuke cached nulls so the next request retries instead of reusing the failure sentinel.
             $this->cache->delete($cacheKey);
         }
 
         return $token;
     }
+
+    /**
+     * Returns true when credentials are available from DB or environment.
+     */
+    public function isConfigured(): bool
+    {
+        $clientId = trim((string) $this->settings->getValue('SPOTIFY_CLIENT_ID', $this->clientId ?? ''));
+        $clientSecret = trim((string) $this->settings->getValue('SPOTIFY_CLIENT_SECRET', $this->clientSecret ?? ''));
+        return $clientId !== '' && $clientSecret !== '';
+    }
 }