[mob][photos] Make sure models are downloaded

mobile/lib/services/machine_learning/ml_model.dart

@@ -5,6 +5,7 @@ import "package:onnx_dart/onnx_dart.dart";
 import "package:onnxruntime/onnxruntime.dart";
 import "package:photos/services/machine_learning/onnx_env.dart";
 import "package:photos/services/remote_assets_service.dart";
+import "package:synchronized/synchronized.dart";
 
 abstract class MlModel {
   static final Logger isolateLogger = Logger("MlModelInIsolate");
@@ -16,6 +17,8 @@ abstract class MlModel {
 
   String get modelName;
 
+  final _downloadModelLock = Lock();
+
   static final bool usePlatformPlugin = Platform.isAndroid;
 
   bool get isInitialized =>
@@ -32,9 +35,21 @@ abstract class MlModel {
   int _nativePluginSessionIndex = -1;
 
   Future<(String, String)> getModelNameAndPath() async {
-    final path =
-        await RemoteAssetsService.instance.getAssetPath(modelRemotePath);
-    return (modelName, path);
+    return _downloadModelLock.synchronized(() async {
+      final path =
+          await RemoteAssetsService.instance.getAssetPath(modelRemotePath);
+      return (modelName, path);
+    });
+  }
+
+  Future<void> downloadModel([bool forceRefresh = false]) async {
+    return _downloadModelLock.synchronized(() async {
+      if (forceRefresh) {
+        await RemoteAssetsService.instance.getAssetIfUpdated(modelRemotePath);
+      } else {
+        await RemoteAssetsService.instance.getAsset(modelRemotePath);
+      }
+    });
   }
 
   void storeSessionAddress(int address) {

mobile/lib/services/machine_learning/ml_service.dart

@@ -43,8 +43,10 @@ class MLService {
   factory MLService() => instance;
 
   final _initModelLock = Lock();
+  final _downloadModelLock = Lock();
 
   bool _isInitialized = false;
+  bool areModelsDownloaded = false;
 
   late String client;
 
@@ -52,8 +54,6 @@ class MLService {
 
   bool get showClusteringIsHappening => _showClusteringIsHappening;
 
-  bool modelsAreLoading = false;
-
   bool debugIndexingDisabled = false;
   bool _showClusteringIsHappening = false;
   bool _mlControllerStatus = false;
@@ -64,7 +64,7 @@ class MLService {
   static const _kForceClusteringFaceCount = 8000;
 
   /// Only call this function once at app startup, after that you can directly call [runAllML]
-  Future<void> init() async {
+  Future<void> init({bool firstTime = false}) async {
     if (localSettings.isFaceIndexingEnabled == false || _isInitialized) {
       return;
     }
@@ -78,6 +78,9 @@ class MLService {
     // Activate FaceRecognitionService
     await FaceRecognitionService.instance.init();
 
+    // Download models if not already downloaded
+    unawaited(_ensureDownloadedModels(firstTime));
+
     // Listen on MachineLearningController
     Bus.instance.on<MachineLearningControlEvent>().listen((event) {
       if (localSettings.isFaceIndexingEnabled == false) {
@@ -509,6 +512,25 @@ class MLService {
     return actuallyRanML;
   }
 
+  Future<void> _ensureDownloadedModels([bool forceRefresh = false]) async {
+    if (_downloadModelLock.locked) {
+      _logger.finest("Download models already in progress");
+    }
+    return _downloadModelLock.synchronized(() async {
+      if (areModelsDownloaded) {
+        _logger.finest("Models already downloaded");
+        return;
+      }
+      _logger.info('Downloading models');
+      await Future.wait([
+        FaceDetectionService.instance.downloadModel(forceRefresh),
+        FaceEmbeddingService.instance.downloadModel(forceRefresh),
+        ClipImageEncoder.instance.downloadModel(forceRefresh),
+      ]);
+      areModelsDownloaded = true;
+    });
+  }
+
   Future<void> _ensureLoadedModels(FileMLInstruction instruction) async {
     return _initModelLock.synchronized(() async {
       final faceDetectionLoaded = FaceDetectionService.instance.isInitialized;
@@ -522,7 +544,6 @@ class MLService {
         return;
       }
 
-      modelsAreLoading = true;
       _logger.info(
         'Loading models. faces: $shouldLoadFaces, clip: $shouldLoadClip',
       );
@@ -530,7 +551,6 @@ class MLService {
           .loadModels(loadFaces: shouldLoadFaces, loadClip: shouldLoadClip);
       _logger.info('Models loaded');
       _logStatus();
-      modelsAreLoading = false;
     });
   }
 

mobile/lib/ui/settings/machine_learning_settings_page.dart

@@ -119,8 +119,7 @@ class _MachineLearningSettingsPageState
             onChanged: () async {
               final isEnabled = await localSettings.toggleFaceIndexing();
               if (isEnabled) {
-                await MLService.instance.init();
-                MLService.instance.downloadModels().ignore();
+                await MLService.instance.init(firstTime: true);
 
                 await SemanticSearchService.instance.init();
                 unawaited(MLService.instance.runAllML(force: true));
@@ -138,9 +137,9 @@ class _MachineLearningSettingsPageState
           height: 12,
         ),
         hasEnabled
-            ? MLService.instance.modelsAreLoading
-                ? const ModelLoadingState()
-                : const MLStatusWidget()
+            ? MLService.instance.areModelsDownloaded
+                ? const MLStatusWidget()
+                : const ModelLoadingState()
             : const SizedBox.shrink(),
       ],
     );