improved performance and battery usage on older devices

lib/view/pages/files/search/files_search_controller.dart

@@ -26,6 +26,14 @@ class FilesSearchController extends ChangeNotifier {
   Object? _serverError;
   int _serverEpoch = 0;
   bool _disposed = false;
+  Future<List<CacheableFile>>? _localIndex;
+
+  Future<List<CacheableFile>> _searchLocal(List<String> pathScope) async =>
+      searchLocalCacheIndex(
+        await (_localIndex ??= loadLocalCacheIndex()),
+        _query,
+        pathScope: pathScope,
+      );
 
   /// Guards against the race where the search delegate is closed (and the
   /// controller disposed) while a debounced cache scan or server call is
@@ -80,7 +88,7 @@ class FilesSearchController extends ChangeNotifier {
     _serverError = null;
     _safeNotify();
 
-    final cacheHits = await searchLocalCaches(_query, pathScope: _pathScope);
+    final cacheHits = await _searchLocal(_pathScope);
     if (epoch != _serverEpoch) return;
     _cacheResults = cacheHits;
     _safeNotify();
@@ -101,7 +109,7 @@ class FilesSearchController extends ChangeNotifier {
     _serverError = null;
     _safeNotify();
 
-    final cacheHits = await searchLocalCaches(_query);
+    final cacheHits = await _searchLocal(const []);
     if (epoch != _serverEpoch) return;
     _cacheResults = cacheHits;
     _safeNotify();

lib/view/pages/files/search/files_search_results.dart

@@ -104,32 +104,43 @@ class FilesSearchResults extends StatelessWidget {
   Widget _resultList(BuildContext context, List<CacheableFile> combined) {
     final groups = _groupByParent(combined);
     final orderedKeys = groups.keys.toList()..sort();
-    final items = <Widget>[];
-    for (final folder in orderedKeys) {
-      final segments = _segmentsOf(folder);
-      items.add(
-        _FolderHeader(
-          folder: folder,
-          onOpen: () {
-            onResultTap?.call();
-            AppRoutes.openFolder(context, segments);
-          },
-        ),
-      );
-      for (final file in groups[folder]!) {
-        items.add(
-          FileElement(
-            file,
-            segments,
-            controller.retry,
-            highlight: controller.query,
-          ),
+    // Flat (folder header | file) rows built lazily: results can run into
+    // the hundreds and arrive in several batches per query.
+    final rows = <(String, CacheableFile?)>[
+      for (final folder in orderedKeys) ...[
+        (folder, null),
+        for (final file in groups[folder]!) (folder, file),
+      ],
+    ];
+    return ListView.builder(
+      padding: EdgeInsets.zero,
+      itemCount: rows.length,
+      itemBuilder: (context, index) {
+        final (folder, file) = rows[index];
+        final segments = _segmentsOf(folder);
+        if (file == null) {
+          return _FolderHeader(
+            key: ValueKey('folder:$folder'),
+            folder: folder,
+            onOpen: () {
+              onResultTap?.call();
+              AppRoutes.openFolder(context, segments);
+            },
+          );
+        }
+        return FileElement(
+          file,
+          segments,
+          controller.retry,
+          key: ValueKey('file:${file.path}'),
+          highlight: controller.query,
         );
-      }
-    }
-    return ListView(padding: EdgeInsets.zero, children: items);
+      },
+    );
   }
 
+  static final RegExp _edgeSlashes = RegExp(r'^/+|/+$');
+
   Map<String, List<CacheableFile>> _groupByParent(List<CacheableFile> files) {
     final map = <String, List<CacheableFile>>{};
     for (final file in files) {
@@ -139,7 +150,7 @@ class FilesSearchResults extends StatelessWidget {
   }
 
   String _parentOf(CacheableFile file) {
-    final stripped = file.path.replaceAll(RegExp(r'^/+|/+$'), '');
+    final stripped = file.path.replaceAll(_edgeSlashes, '');
     final segments = stripped.split('/');
     if (segments.length <= 1) return '/';
     segments.removeLast();
@@ -147,7 +158,7 @@ class FilesSearchResults extends StatelessWidget {
   }
 
   List<String> _segmentsOf(String folder) {
-    final stripped = folder.replaceAll(RegExp(r'^/+|/+$'), '');
+    final stripped = folder.replaceAll(_edgeSlashes, '');
     if (stripped.isEmpty) return const [];
     return stripped.split('/');
   }
@@ -156,7 +167,11 @@ class FilesSearchResults extends StatelessWidget {
 class _FolderHeader extends StatelessWidget {
   final String folder;
   final VoidCallback onOpen;
-  const _FolderHeader({required this.folder, required this.onOpen});
+  const _FolderHeader({
+    required this.folder,
+    required this.onOpen,
+    super.key,
+  });
 
   @override
   Widget build(BuildContext context) {

lib/view/pages/files/search/local_cache_search.dart

@@ -1,49 +1,29 @@
 import 'dart:convert';
 
-import 'package:localstore/localstore.dart';
+import 'package:flutter/foundation.dart';
 
+import '../../../../api/cache_store.dart';
 import '../../../../api/marianumcloud/webdav/queries/list_files/cacheable_file.dart';
 import '../../../../api/marianumcloud/webdav/queries/list_files/list_files_response.dart';
-import '../../../../api/request_cache.dart';
 
 /// Document key prefix used by `ListFilesCache._documentId`.
 const String _folderCachePrefix = 'wd-folder-';
 
-/// Scans every cached folder listing in Localstore and returns files/folders
-/// whose name contains [query] (case-insensitive).
-///
-/// [pathScope] restricts results to entries whose WebDAV path starts with
-/// the given folder. Pass an empty list (or null) to search globally.
-///
-/// [docs] is an injection seam for tests — production callers leave it null
-/// so the helper reads from the real Localstore.
-Future<List<CacheableFile>> searchLocalCaches(
-  String query, {
-  List<String>? pathScope,
-  Map<String, dynamic>? docs,
-}) async {
-  final trimmed = query.trim();
-  if (trimmed.isEmpty) return const [];
-  final needle = trimmed.toLowerCase();
-  final scopePrefix = pathScope == null || pathScope.isEmpty
-      ? ''
-      : '${pathScope.join('/')}/';
-
-  final raw =
-      docs ??
-      await Localstore.instance.collection(RequestCache.collection).get();
-  if (raw == null || raw.isEmpty) return const [];
-
-  final results = <String, CacheableFile>{};
-  for (final entry in raw.entries) {
-    final docKey = entry.key.split('/').last;
-    if (!docKey.startsWith(_folderCachePrefix)) continue;
-
-    final value = entry.value;
-    if (value is! Map) continue;
-    final json = value['json'];
-    if (json is! String) continue;
+/// Every file and folder from the cached folder listings, deduplicated by
+/// path. Built once per search session: reading and parsing all listings on
+/// each keystroke used to stall typing.
+Future<List<CacheableFile>> loadLocalCacheIndex() async {
+  final entries = await CacheStore.instance.readAll(prefix: _folderCachePrefix);
+  if (entries.isEmpty) return const [];
+  final payloads = [for (final entry in entries.values) entry.json];
+  return compute(buildLocalCacheIndex, payloads);
+}
 
+/// Parses cached `ListFilesResponse` payloads into a deduplicated file list.
+/// Unparsable payloads are skipped.
+List<CacheableFile> buildLocalCacheIndex(List<String> payloads) {
+  final byPath = <String, CacheableFile>{};
+  for (final json in payloads) {
     final ListFilesResponse listing;
     try {
       listing = ListFilesResponse.fromJson(
@@ -52,14 +32,32 @@ Future<List<CacheableFile>> searchLocalCaches(
     } on Object {
       continue;
     }
-
     for (final file in listing.files) {
-      if (!file.name.toLowerCase().contains(needle)) continue;
-      if (scopePrefix.isNotEmpty && !file.path.startsWith(scopePrefix)) {
-        continue;
-      }
-      results[file.path] ??= file;
+      byPath[file.path] ??= file;
     }
   }
-  return results.values.toList();
+  return byPath.values.toList();
+}
+
+/// Files in [index] whose name contains [query] (case-insensitive).
+///
+/// [pathScope] restricts results to entries whose WebDAV path starts with
+/// the given folder. Pass an empty list (or null) to search globally.
+List<CacheableFile> searchLocalCacheIndex(
+  List<CacheableFile> index,
+  String query, {
+  List<String>? pathScope,
+}) {
+  final trimmed = query.trim();
+  if (trimmed.isEmpty) return const [];
+  final needle = trimmed.toLowerCase();
+  final scopePrefix = pathScope == null || pathScope.isEmpty
+      ? ''
+      : '${pathScope.join('/')}/';
+  return [
+    for (final file in index)
+      if (file.lowerName.contains(needle) &&
+          (scopePrefix.isEmpty || file.path.startsWith(scopePrefix)))
+        file,
+  ];
 }