speed up series update

lib/core/api/backend_api.dart

@@ -185,6 +185,39 @@ class BackendApi {
     return (map['id'] as num).toInt();
   }
 
+  Future<int> upsertEpisodesBulk(int seasonId, List<Map<String, dynamic>> episodes) async {
+    final map = await _post({
+      'action': 'upsert_episodes_bulk',
+      'season_id': seasonId,
+      'episodes': episodes,
+    });
+    return (map['count'] as num?)?.toInt() ?? 0;
+  }
+
+  Future<Map<int, int>> upsertSeasonsBulk(int showId, List<Map<String, dynamic>> seasons) async {
+    final map = await _post({
+      'action': 'upsert_seasons_bulk',
+      'show_id': showId,
+      'seasons': seasons,
+    });
+    final m = <int,int>{};
+    final any = map['map'];
+    if (any is Map) {
+      for (final e in any.entries) {
+        final k = int.tryParse(e.key.toString());
+        final v = (e.value as num?)?.toInt();
+        if (k != null && v != null) m[k] = v;
+      }
+    }
+    return m;
+  }
+
+  Future<Map<String, dynamic>> getCapabilities() async {
+    final map = await _post({'action': 'get_capabilities'});
+    final caps = map['capabilities'];
+    return caps is Map<String, dynamic> ? caps : (caps as Map).cast<String, dynamic>();
+  }
+
   Future<int?> getShowDbIdByTmdbId(int tmdbId) async {
     final map = await _post({'action': 'get_show_by_tmdb', 'tmdb_id': tmdbId});
     final v = map['id'];

lib/core/async_utils.dart

@@ -0,0 +1,30 @@
+typedef CancelCheck = bool Function();
+
+Iterable<List<T>> _chunked<T>(List<T> list, int size) sync* {
+  if (size <= 0) size = 1;
+  for (var i = 0; i < list.length; i += size) {
+    final end = i + size;
+    yield list.sublist(i, end > list.length ? list.length : end);
+  }
+}
+
+Future<void> runChunked<T>(
+  Iterable<T> items,
+  int chunkSize,
+  Future<void> Function(T item) task, {
+  CancelCheck? isCancelled,
+}) async {
+  final list = items.toList();
+  for (final chunk in _chunked(list, chunkSize)) {
+    if (isCancelled?.call() == true) break;
+    await Future.wait(
+      chunk.map((e) async {
+        if (isCancelled?.call() == true) return;
+        await task(e);
+      }),
+      eagerError: false,
+    );
+    if (isCancelled?.call() == true) break;
+  }
+}
+

lib/core/config.dart

@@ -22,4 +22,15 @@ class AppConfig {
 
     ///defaultValue: 'eyJhbGciOiJIUzI1NiJ9.eyJhdWQiOiJhMzMyNzFiOWU1NGNkY2I5YTgwNjgwZWFmNTUyMmYxYiIsIm5iZiI6MTM0ODc2NTY2MS4wLCJzdWIiOiI1MDY0ODdkZDE5YzI5NTY2M2MwMDBhOGIiLCJzY29wZXMiOlsiYXBpX3JlYWQiXSwidmVyc2lvbiI6MX0.m26QybYBGQVY8OuL87FFae3ThPqAnOqEwgbLMtnH0wo'
   );
+
+  // Concurrency caps
+  static const tmdbSeasonFetchConcurrency = int.fromEnvironment(
+    'TMDB_SEASON_CONCURRENCY',
+    defaultValue: 3,
+  );
+
+  static const dbEpisodeUpsertConcurrency = int.fromEnvironment(
+    'DB_EPISODE_UPSERT_CONCURRENCY',
+    defaultValue: 12,
+  );
 }