[mob][photos] Fallback if ML is off

mobile/lib/services/memories_cache_service.dart

@@ -82,9 +82,13 @@ class MemoriesCacheService {
     return _prefs.getBool(_showAnyMemoryKey) ?? true;
   }
 
-  bool get enableSmartMemories => flagService.showSmartMemories;
+  bool get enableSmartMemories =>
+      flagService.showSmartMemories && flagService.hasGrantedMLConsent;
 
   Future<void> _checkIfTimeToUpdateCache() async {
+    if (!enableSmartMemories) {
+      return;
+    }
     if (lastMemoriesCacheUpdateTime <
         DateTime.now()
             .subtract(kMemoriesUpdateFrequency)
@@ -121,6 +125,7 @@ class MemoriesCacheService {
     if (!showAnyMemories || !enableSmartMemories) {
       return;
     }
+    await _checkIfTimeToUpdateCache();
     try {
       if ((!_shouldUpdate && !forced) || _isUpdateInProgress) {
         _logger.info(
@@ -276,10 +281,10 @@ class MemoriesCacheService {
     }
   }
 
-  Future<List<SmartMemory>> _getMemoriesFromCache() async {
+  Future<List<SmartMemory>?> _getMemoriesFromCache() async {
     final cache = await _readCacheFromDisk();
     if (cache == null) {
-      return [];
+      return null;
     }
     final result = await _fromCacheToMemories(cache);
     return result;
@@ -289,10 +294,22 @@ class MemoriesCacheService {
     if (!showAnyMemories) {
       return [];
     }
+    if (!enableSmartMemories) {
+      final fillerMemories = await smartMemoriesService.calcFillerResults();
+      return fillerMemories;
+    }
     if (_cachedMemories != null) {
       return _cachedMemories!;
     }
     _cachedMemories = await _getMemoriesFromCache();
+    if (_cachedMemories == null) {
+      await updateCache(forced: true);
+      _cachedMemories = await _getMemoriesFromCache();
+    }
+    if (_cachedMemories!.isEmpty) {
+      _logger.severe("No memories found in (computed) cache, getting fillers");
+      _cachedMemories = await smartMemoriesService.calcFillerResults();
+    }
     return _cachedMemories!;
   }
 

mobile/lib/services/smart_memories_service.dart

@@ -135,6 +135,15 @@ class SmartMemoriesService {
     }
   }
 
+  Future<List<FillerMemory>> calcFillerResults() async {
+    final now = DateTime.now();
+    final allFiles = Set<EnteFile>.from(
+      await SearchService.instance.getAllFilesForSearch(),
+    );
+    final fillerMemories = await _getFillerResults(allFiles, now);
+    return fillerMemories;
+  }
+
   void _deductUsedMemories(
     Set<EnteFile> files,
     List<SmartMemory> memories,

mobile/lib/ui/home/memories/memories_widget.dart

@@ -54,7 +54,7 @@ class _MemoriesWidgetState extends State<MemoriesWidget> {
 
   @override
   Widget build(BuildContext context) {
-    if (!MemoriesService.instance.showMemories) {
+    if (!memoriesCacheService.showAnyMemories) {
       return const SizedBox.shrink();
     }
     if (memoriesCacheService.enableSmartMemories) {
@@ -69,9 +69,6 @@ class _MemoriesWidgetState extends State<MemoriesWidget> {
         null,
       ),
       builder: (context, snapshot) {
-        if (snapshot.hasData && snapshot.data!.isEmpty) {
-          return _oldMemories();
-        }
         if (snapshot.hasError || !snapshot.hasData) {
           return SizedBox(
             height: _maxHeight + 12 + 10,