implemented background prefetching for files root, added 24-hour caching for root directory listing, and enabled cache renewal for manual refreshes

lib/api/marianumcloud/webdav/queries/list_files/list_files_cache.dart

@@ -16,8 +16,9 @@ class ListFilesCache extends SimpleCache<ListFilesResponse> {
     super.onNetworkData,
     super.onError,
     required String path,
+    super.renew = false,
   }) : super(
-         cacheTime: RequestCache.cacheNothing,
+         cacheTime: _cacheTimeFor(path),
          loader: () => ListFiles(ListFilesParams(path)).run(),
          fromJson: ListFilesResponse.fromJson,
          onUpdate: onUpdate,
@@ -25,6 +26,44 @@ class ListFilesCache extends SimpleCache<ListFilesResponse> {
     start(_documentId(path));
   }
 
+  /// The Nextcloud root listing is significantly slower than subfolders on
+  /// our instance and frequently returns HTTP 500. Since its content rarely
+  /// changes, the root payload is cached for a full day so app-resume and
+  /// connectivity-change auto-refetch triggers do not re-hit the slow root
+  /// endpoint within the same day. To avoid a long wait on the very first
+  /// open of the Files page, `prefetchRootListing` (called from `main`)
+  /// kicks off an async warm-up fetch in the background while the user is
+  /// still on the launch screen / other modules. Subfolders keep the
+  /// previous "always refetch on visit" TTL because their content changes
+  /// more often. Explicit user refreshes (rename, delete, copy/move,
+  /// upload) bypass the TTL via the inherited [renew] flag or via
+  /// [invalidate].
+  static int _cacheTimeFor(String path) {
+    final stripped = path.replaceAll('/', '').trim();
+    return stripped.isEmpty
+        ? RequestCache.cacheDay
+        : RequestCache.cacheNothing;
+  }
+
+  /// Triggers a root-listing fetch in the background if no cached payload
+  /// exists yet. Intended to be called once after login from `main` so the
+  /// (slow) root listing is already populated by the time the user
+  /// navigates to the Files module.
+  ///
+  /// No-ops when a cached root payload is already present in localstore —
+  /// the regular TTL handling in [RequestCache] takes over from there.
+  static Future<void> prefetchRootListing() async {
+    const rootPath = '';
+    final cached = await Localstore.instance
+        .collection(RequestCache.collection)
+        .doc(_documentId(rootPath))
+        .get();
+    if (cached != null) return;
+    // Drive the same code path as a regular fetch so the result lands in
+    // the cache; we don't care about the in-memory callback here.
+    ListFilesCache(path: rootPath, onUpdate: (_) {});
+  }
+
   static String _documentId(String path) {
     final cacheName = md5
         .convert(utf8.encode('MarianumMobile-$path'))

lib/main.dart

@@ -17,6 +17,7 @@ import 'package:path_provider/path_provider.dart';
 import 'package:persistent_bottom_nav_bar_v2/persistent_bottom_nav_bar_v2.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
+import 'api/marianumcloud/webdav/queries/list_files/list_files_cache.dart';
 import 'api/mhsl/breaker/get_breakers/get_breakers_response.dart';
 import 'app.dart';
 import 'background/widget_background_task.dart';
@@ -91,6 +92,20 @@ Future<void> main() async {
     ),
   );
 
+  // Warm up the Nextcloud root listing in the background while the user is
+  // still on the launch screen / other modules — the root endpoint is slow
+  // on our instance, so kicking it off early means the Files page already
+  // has data ready by the time the user navigates to it. No-op when a
+  // cached payload is already present, so this does not undo the day-long
+  // root cache TTL.
+  if (AccountData().isPopulated()) {
+    unawaited(
+      ListFilesCache.prefetchRootListing().onError(
+        (e, _) => log('Files root prefetch failed: $e'),
+      ),
+    );
+  }
+
   if (kReleaseMode) {
     ErrorWidget.builder = (error) => Material(
       color: Colors.white,

lib/state/app/modules/files/bloc/files_bloc.dart

@@ -37,7 +37,9 @@ class FilesBloc
   Future<void> refresh() async {
     add(RefetchStarted<FilesState>());
     final path = innerState?.currentPath ?? initialPath;
-    await _query(path);
+    // Explicit user action — bypass the cache TTL so the root listing also
+    // refetches even though it is otherwise cached for a day.
+    await _query(path, renew: true);
   }
 
   Future<void> setPath(List<String> path) async {
@@ -52,7 +54,7 @@ class FilesBloc
     await refresh();
   }
 
-  Future<void> _query(List<String> path) async {
+  Future<void> _query(List<String> path, {bool renew = false}) async {
     final pathString = path.isEmpty ? '/' : path.join('/');
 
     // Drop late results when [setPath] has navigated elsewhere or when the
@@ -71,6 +73,7 @@ class FilesBloc
     try {
       listing = await repo.data.listFiles(
         pathString,
+        renew: renew,
         onCacheData: (cached) {
           if (isStale()) return;
           // Cached payload arrives before the network call settles. Surface it

lib/state/app/modules/files/data_provider/files_data_provider.dart

@@ -11,16 +11,23 @@ class FilesDataProvider {
   /// network call is still pending. The Future itself resolves once both the
   /// cache lookup and the network attempt have settled, throwing if no payload
   /// could be obtained at all.
+  ///
+  /// Pass [renew] for explicit user-triggered reloads (pull-to-refresh, after
+  /// a rename / delete / move / upload). It bypasses the per-path TTL in
+  /// [ListFilesCache] so the root listing — which is otherwise cached for a
+  /// full day — still refetches when the user actively asks for it.
   Future<ListFilesResponse> listFiles(
     String path, {
     void Function(ListFilesResponse)? onCacheData,
     void Function(Object)? onError,
+    bool renew = false,
   }) => resolveFromCache<ListFilesResponse>(
     (onUpdate, onError) => ListFilesCache(
       path: path,
       onUpdate: onUpdate,
       onCacheData: onCacheData,
       onError: onError,
+      renew: renew,
     ),
     onError: onError,
     operationName: 'listFiles',