[mob] Download models before interence

mobile/lib/services/machine_learning/ml_model.dart

@@ -38,6 +38,10 @@ abstract class MlModel {
     }
   }
 
+  Future<void> downloadModel() async {
+    await RemoteAssetsService.instance.getAssetIfUpdated(modelRemotePath);
+  }
+
   Future<void> _loadModelWithEntePlugin(
     String modelName,
     String modelPath,

mobile/lib/services/machine_learning/ml_service.dart

@@ -33,7 +33,9 @@ import "package:photos/services/machine_learning/file_ml/remote_fileml_service.d
 import 'package:photos/services/machine_learning/ml_exceptions.dart';
 import 'package:photos/services/machine_learning/ml_result.dart';
 import "package:photos/services/machine_learning/semantic_search/clip/clip_image_encoder.dart";
+import "package:photos/services/machine_learning/semantic_search/clip/clip_text_tokenizer.dart";
 import "package:photos/services/machine_learning/semantic_search/semantic_search_service.dart";
+import "package:photos/services/remote_assets_service.dart";
 import "package:photos/utils/image_ml_util.dart";
 import "package:photos/utils/ml_util.dart";
 import "package:photos/utils/network_util.dart";
@@ -65,11 +67,13 @@ class MLService {
   factory MLService() => instance;
 
   final _initModelLock = Lock();
+  final _downloadModelLock = Lock();
   final _functionLock = Lock();
   final _initIsolateLock = Lock();
 
   bool _isInitialized = false;
   bool _isModelsInitialized = false;
+  bool areModelDownloaded = false;
   bool _isModelsInitUsingEntePlugin = false;
   bool _isIsolateSpawned = false;
 
@@ -525,6 +529,31 @@ class MLService {
     return actuallyRanML;
   }
 
+  Future<void> downloadModels() {
+    if (areModelDownloaded) {
+      _logger.finest("Models already downloaded");
+      return Future.value();
+    }
+    if (_downloadModelLock.locked) {
+      _logger.finest("Download models already in progress");
+    }
+    return _downloadModelLock.synchronized(() async {
+      if (areModelDownloaded) {
+        return;
+      }
+      _logger.info('Downloading models');
+      await Future.wait([
+        FaceDetectionService.instance.downloadModel(),
+        FaceEmbeddingService.instance.downloadModel(),
+        ClipImageEncoder.instance.downloadModel(),
+        ClipImageEncoder.instance.downloadModel(),
+        RemoteAssetsService.instance
+            .getAsset(ClipTextTokenizer.kVocabRemotePath),
+      ]);
+      areModelDownloaded = true;
+    });
+  }
+
   Future<void> _initModelsUsingFfiBasedPlugin() async {
     return _initModelLock.synchronized(() async {
       if (_isModelsInitialized) return;
@@ -632,7 +661,7 @@ class MLService {
 
   Future<void> _ensureReadyForInference() async {
     await _initIsolate();
-    await _initModelsUsingFfiBasedPlugin();
+    await downloadModels();
     if (Platform.isAndroid) {
       await _initModelUsingEntePlugin();
     } else {

mobile/lib/ui/settings/machine_learning_settings_page.dart

@@ -120,6 +120,8 @@ class _MachineLearningSettingsPageState
               final isEnabled = await localSettings.toggleFaceIndexing();
               if (isEnabled) {
                 await MLService.instance.init();
+                MLService.instance.downloadModels().ignore();
+
                 await SemanticSearchService.instance.init();
                 unawaited(MLService.instance.runAllML(force: true));
               } else {}
@@ -136,7 +138,7 @@ class _MachineLearningSettingsPageState
           height: 12,
         ),
         hasEnabled
-            ? MLService.instance.allModelsLoaded
+            ? MLService.instance.areModelDownloaded
                 ? const MLStatusWidget()
                 : const ModelLoadingState()
             : const SizedBox.shrink(),