Invoke FirebaseProvider's onFunctionCalls callback

lib/src/providers/implementations/firebase_provider.dart

@@ -27,6 +27,9 @@ class FirebaseProvider extends LlmProvider with ChangeNotifier {
   ///
   /// [chatGenerationConfig] is an optional configuration for controlling the
   /// model's generation behavior.
+  ///
+  /// [onFunctionCalls] is an optional callback invoked with the function calls
+  /// collected from a single turn of the model's response.
   FirebaseProvider({
     required GenerativeModel model,
     void Function(Iterable<FunctionCall>)? onFunctionCalls,
@@ -35,6 +38,7 @@ class FirebaseProvider extends LlmProvider with ChangeNotifier {
     GenerationConfig? chatGenerationConfig,
     Future<Map<String, Object?>?> Function(FunctionCall)? onFunctionCall,
   }) : _model = model,
+       _onFunctionCalls = onFunctionCalls,
        _history = history?.toList() ?? [],
        _chatSafetySettings = chatSafetySettings,
        _chatGenerationConfig = chatGenerationConfig,
@@ -43,6 +47,7 @@ class FirebaseProvider extends LlmProvider with ChangeNotifier {
   }
 
   final GenerativeModel _model;
+  final void Function(Iterable<FunctionCall>)? _onFunctionCalls;
   final List<SafetySetting>? _chatSafetySettings;
   final GenerationConfig? _chatGenerationConfig;
   final List<ChatMessage> _history;
@@ -123,6 +128,9 @@ class FirebaseProvider extends LlmProvider with ChangeNotifier {
         break;
       }
 
+      // Notify the caller of the function calls collected in this turn
+      _onFunctionCalls?.call(functionCalls);
+
       // Add newline between responses
       yield '\n';
 

pubspec.yaml

@@ -32,6 +32,8 @@ dependencies:
   waveform_recorder: ^1.8.0
 
 dev_dependencies:
+  firebase_core: ^4.13.0
+  firebase_core_platform_interface: ^8.1.0
   flutter_lints: ^6.0.0
   flutter_test:
     sdk: flutter

test/firebase_provider_test.dart

@@ -0,0 +1,162 @@
+// Copyright 2024 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// ignore_for_file: implementation_imports
+
+import 'package:firebase_ai/firebase_ai.dart';
+import 'package:firebase_ai/src/base_model.dart';
+import 'package:firebase_ai/src/client.dart';
+import 'package:firebase_core/firebase_core.dart';
+import 'package:firebase_core_platform_interface/test.dart';
+import 'package:flutter_ai_toolkit/flutter_ai_toolkit.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+  TestFirebaseCoreHostApi.setUp(_MockFirebaseApp());
+
+  late FirebaseApp app;
+  setUpAll(() async {
+    app = await Firebase.initializeApp();
+  });
+
+  group('FirebaseProvider.onFunctionCalls', () {
+    test(
+      'invokes onFunctionCalls with the calls collected in a turn',
+      () async {
+        final client =
+            _StubApiClient()
+              ..streamResponses.addAll([
+                [_functionCallResponse],
+                [_textResponse],
+              ]);
+
+        final recordedCalls = <FunctionCall>[];
+        final provider = FirebaseProvider(
+          model: _createModel(app, client),
+          onFunctionCalls: recordedCalls.addAll,
+          onFunctionCall: (functionCall) async => {'temperature': 60},
+        );
+
+        await provider
+            .sendMessageStream('What is the temperature?')
+            .drain<void>();
+
+        expect(recordedCalls, hasLength(1));
+        expect(recordedCalls.single.name, 'getTemperature');
+        expect(recordedCalls.single.args, {'city': 'Portland'});
+      },
+    );
+
+    test(
+      'does not invoke onFunctionCalls when no function calls are made',
+      () async {
+        final client = _StubApiClient()..streamResponses.add([_textResponse]);
+
+        final recordedCalls = <FunctionCall>[];
+        final provider = FirebaseProvider(
+          model: _createModel(app, client),
+          onFunctionCalls: recordedCalls.addAll,
+        );
+
+        await provider.sendMessageStream('Just say something').drain<void>();
+
+        expect(recordedCalls, isEmpty);
+      },
+    );
+  });
+}
+
+GenerativeModel _createModel(FirebaseApp app, ApiClient client) =>
+    createModelWithClient(
+      app: app,
+      location: 'us-central1',
+      model: 'some-model',
+      client: client,
+      useAgentPlatform: false,
+    );
+
+const _functionCallResponse = {
+  'candidates': [
+    {
+      'content': {
+        'role': 'model',
+        'parts': [
+          {
+            'functionCall': {
+              'name': 'getTemperature',
+              'args': {'city': 'Portland'},
+            },
+          },
+        ],
+      },
+      'finishReason': 'STOP',
+    },
+  ],
+};
+
+const _textResponse = {
+  'candidates': [
+    {
+      'content': {
+        'role': 'model',
+        'parts': [
+          {'text': 'The temperature is 60F.'},
+        ],
+      },
+      'finishReason': 'STOP',
+    },
+  ],
+};
+
+final class _StubApiClient implements ApiClient {
+  final streamResponses = <List<Map<String, Object?>>>[];
+
+  @override
+  Future<Map<String, Object?>> makeRequest(
+    Uri uri,
+    Map<String, Object?> body,
+  ) => throw UnimplementedError();
+
+  @override
+  Stream<Map<String, Object?>> streamRequest(
+    Uri uri,
+    Map<String, Object?> body,
+  ) => Stream.fromIterable(streamResponses.removeAt(0));
+}
+
+class _MockFirebaseApp implements TestFirebaseCoreHostApi {
+  @override
+  Future<CoreInitializeResponse> initializeApp(
+    String appName,
+    CoreFirebaseOptions initializeAppRequest,
+  ) async => CoreInitializeResponse(
+    name: appName,
+    options: initializeAppRequest,
+    pluginConstants: {},
+  );
+
+  @override
+  Future<List<CoreInitializeResponse>> initializeCore() async => [
+    CoreInitializeResponse(
+      name: defaultFirebaseAppName,
+      options: CoreFirebaseOptions(
+        apiKey: '123',
+        projectId: '123',
+        appId: '123',
+        messagingSenderId: '123',
+      ),
+      pluginConstants: {},
+    ),
+  ];
+
+  @override
+  Future<CoreFirebaseOptions> optionsFromResource() async =>
+      CoreFirebaseOptions(
+        apiKey: '123',
+        projectId: '123',
+        appId: '123',
+        messagingSenderId: '123',
+      );
+}