createModel method

Implementation

@override
Future<InferenceModel> createModel({
  required ModelType modelType,
  ModelFileType fileType = ModelFileType.task,
  int maxTokens = 1024,
  PreferredBackend? preferredBackend,
  List<int>? loraRanks,
  int? maxNumImages,
  bool supportImage = false,
}) async {
  // Check if model is ready through unified system
  final manager = _unifiedManager;
  final activeModel = manager.activeInferenceModel;

  // No active inference model - user must set one first
  if (activeModel == null) {
    throw Exception('No active inference model set. Use `FlutterGemma.installModel()` or `modelManager.setActiveModel()` to set a model first');
  }

  // Check if singleton exists and matches the active model
  if (_initCompleter != null && _initializedModel != null && _lastActiveInferenceSpec != null) {
    final currentSpec = _lastActiveInferenceSpec!;
    final requestedSpec = activeModel as InferenceModelSpec;

    if (currentSpec.name != requestedSpec.name) {
      // Active model changed - close old model and create new one
      debugPrint('⚠️  Active model changed: ${currentSpec.name} → ${requestedSpec.name}');
      debugPrint('🔄 Closing old model and creating new one...');
      await _initializedModel?.close();
      // onClose callback will reset _initializedModel and _initCompleter
      _lastActiveInferenceSpec = null;
    } else {
      // Same model - return existing singleton
      debugPrint('ℹ️  Reusing existing model instance for ${requestedSpec.name}');
      return _initCompleter!.future;
    }
  }

  // If singleton doesn't exist or was just closed, create new one
  if (_initCompleter case Completer<InferenceModel> completer) {
    return completer.future;
  }

  final completer = _initCompleter = Completer<InferenceModel>();

  // Verify the active model is still installed
  final isModelInstalled = await manager.isModelInstalled(activeModel);
  if (!isModelInstalled) {
    completer.completeError(
      Exception('Active model is no longer installed. Use the `modelManager` to load the model first'),
    );
    return completer.future;
  }

  // Get the actual model file path through unified system
  final modelFilePaths = await manager.getModelFilePaths(activeModel);
  if (modelFilePaths == null || modelFilePaths.isEmpty) {
    completer.completeError(
      Exception('Model file paths not found. Use the `modelManager` to load the model first'),
    );
    return completer.future;
  }

  final modelPath = modelFilePaths.values.first;
  final modelFile = File(modelPath);

  if (!await modelFile.exists()) {
    completer.completeError(
      Exception('Model file not found at path: ${modelFile.path}'),
    );
    return completer.future;
  }

  debugPrint('Using unified model file: $modelPath');

  try {
    await _platformService.createModel(
      maxTokens: maxTokens,
      modelPath: modelPath,
      loraRanks: loraRanks ?? supportedLoraRanks,
      preferredBackend: preferredBackend,
      maxNumImages: supportImage ? (maxNumImages ?? 1) : null,
    );

    final model = _initializedModel = MobileInferenceModel(
      maxTokens: maxTokens,
      modelType: modelType,
      fileType: fileType,
      preferredBackend: preferredBackend,
      supportedLoraRanks: loraRanks ?? supportedLoraRanks,
      supportImage: supportImage,
      maxNumImages: maxNumImages,
      onClose: () {
        _initializedModel = null;
        _initCompleter = null;
        _lastActiveInferenceSpec = null;
      },
    );

    // Save the spec that was used to create this model
    _lastActiveInferenceSpec = activeModel as InferenceModelSpec;

    completer.complete(model);
    return model;
  } catch (e, st) {
    completer.completeError(e, st);
    Error.throwWithStackTrace(e, st);
  }
}