speed up series update

lib/features/import/import_screen.dart

@@ -2,6 +2,8 @@ import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:dio/dio.dart';
 import '../../core/api/backend_api.dart';
+import '../../core/config.dart';
+import '../../core/async_utils.dart';
 import '../shared/providers.dart';
 
 class ImportScreen extends ConsumerStatefulWidget {
@@ -18,6 +20,7 @@ class _ImportScreenState extends ConsumerState<ImportScreen> {
       TextEditingController(text: '1396, 1399'); // Breaking Bad, GoT
   String _log = '';
   bool _busy = false;
+  bool _cancel = false;
 
   void _append(String msg) => setState(() => _log += '$msg\n');
 
@@ -44,7 +47,7 @@ class _ImportScreenState extends ConsumerState<ImportScreen> {
   }
 
   Future<void> _importShows() async {
-    setState(() => _busy = true);
+    setState(() { _busy = true; _cancel = false; });
     final tmdb = ref.read(tmdbApiProvider);
     final backend = ref.read(backendApiProvider);
 
@@ -54,6 +57,7 @@ class _ImportScreenState extends ConsumerState<ImportScreen> {
         .map(int.parse);
 
     for (final showId in ids) {
+      if (_cancel) break;
       try {
         _append('Serie $showId: TMDB laden …');
         final showJson = await tmdb.getShow(showId);
@@ -62,27 +66,51 @@ class _ImportScreenState extends ConsumerState<ImportScreen> {
         await backend.upsertShow(showJson);
         _append('Serie $showId: Show OK ✓');
 
-        final seasons = (showJson['seasons'] as List? ?? const [])
+        final seasonNos = (showJson['seasons'] as List? ?? const [])
             .where((s) => (s['season_number'] ?? 0) is int)
-            .cast<Map<String, dynamic>>();
+            .map((s) => (s as Map<String, dynamic>)['season_number'] as int)
+            .where((n) => n >= 0)
+            .toList();
 
-        for (final s in seasons) {
-          final seasonNo = (s['season_number'] as num).toInt();
-          if (seasonNo < 0) continue;
-          _append('  S$seasonNo: TMDB Season laden …');
+        // Fetch all seasons (limited concurrency)
+        final seasonsJson = <int, Map<String, dynamic>>{};
+        await runChunked<int>(
+          seasonNos,
+          AppConfig.tmdbSeasonFetchConcurrency,
+          (sNo) async {
+            if (_cancel) return;
+            final sj = await tmdb.getSeason(showId, sNo);
+            seasonsJson[sNo] = sj;
+          },
+          isCancelled: () => _cancel,
+        );
 
-          final seasonJson = await tmdb.getSeason(showId, seasonNo);
-          final dbShowId = await _getDbShowIdByTmdb(backend, showId);
-          final dbSeasonId = await backend.upsertSeason(dbShowId, seasonJson);
+        final dbShowId = await _getDbShowIdByTmdb(backend, showId);
+        // Bulk upsert seasons and get IDs
+        Map<int,int> seasonIds = const {};
+        try {
+          seasonIds = await backend.upsertSeasonsBulk(dbShowId, seasonsJson.values.toList());
+        } catch (_) {
+          final m = <int,int>{};
+          for (final entry in seasonsJson.entries) { final id = await backend.upsertSeason(dbShowId, entry.value); m[entry.key] = id; }
+          seasonIds = m;
+        }
 
-          _append('  S$seasonNo: Season OK (db:$dbSeasonId)');
-
-          final eps = (seasonJson['episodes'] as List? ?? const [])
-              .cast<Map<String, dynamic>>();
-          for (final e in eps) {
-            await backend.upsertEpisode(dbSeasonId, e);
+        for (final entry in seasonsJson.entries) {
+          if (_cancel) break;
+          final sNo = entry.key; final seasonJson = entry.value; final dbSeasonId = seasonIds[sNo]; if (dbSeasonId == null) continue;
+          _append('  S$sNo: upserting episodes …');
+          final eps = (seasonJson['episodes'] as List? ?? const []).cast<Map<String, dynamic>>();
+          try { await backend.upsertEpisodesBulk(dbSeasonId, eps); }
+          catch (_) {
+            await runChunked<Map<String, dynamic>>(
+              eps,
+              AppConfig.dbEpisodeUpsertConcurrency,
+              (e) async { if (_cancel) return; await backend.upsertEpisode(dbSeasonId, e); },
+              isCancelled: () => _cancel,
+            );
           }
-          _append('  S$seasonNo: ${eps.length} Episoden OK ✓');
+          _append('  S$sNo: ${eps.length} Episoden OK ✓');
         }
       } catch (e) {
         // 👇 Hier kommt der erweiterte Catch hin!
@@ -139,6 +167,12 @@ class _ImportScreenState extends ConsumerState<ImportScreen> {
                   onPressed: _busy ? null : _importShows,
                   child: const Text('Import Serien'),
                 ),
+                const SizedBox(width: 8),
+                if (_busy)
+                  TextButton(
+                    onPressed: () => setState(() => _cancel = true),
+                    child: const Text('Abbrechen'),
+                  ),
               ],
             ),
             const SizedBox(height: 12),