fix(vertexai): update history getter to reflect google_generative_ai updates (#13040)

Toglefritz · web-flow · commit cc542d76b989 · 2024-08-19T11:13:54.000-07:00
* fix(chat-session): update history getter to reflect google_generative_ai updates

- Removed the private _history member from the Flutterfire ChatSession class
- Updated the constructor to accept initialHistory parameter
- Modified the startChat method to use initialHistory
- Updated the history getter to return history from google_generative_ai package

This ensures that the history returned by the Flutterfire ChatSession class is always up-to-date and consistent with the state of the chat session.

* docs(chat-session): update comments for history behavior

- Clarified that the history is maintained by the google_generative_ai package
- Modified history getter comment to highlight that it returns the most current state of the chat session

* chore: format code using Melos
diff --git a/packages/firebase_vertexai/firebase_vertexai/example/lib/main.dart b/packages/firebase_vertexai/firebase_vertexai/example/lib/main.dart
@@ -77,7 +77,7 @@ class ChatWidget extends StatefulWidget {
 class _ChatWidgetState extends State<ChatWidget> {
   late final GenerativeModel _model;
   late final GenerativeModel _functionCallModel;
-  late final ChatSession _chat;
+  ChatSession? _chat;
   final ScrollController _scrollController = ScrollController();
   final TextEditingController _textController = TextEditingController();
   final FocusNode _textFieldFocus = FocusNode();
@@ -289,6 +289,16 @@ class _ChatWidgetState extends State<ChatWidget> {
               ],
             ),
           ),
+          Padding(
+            padding: const EdgeInsets.only(
+              left: 15,
+              right: 15,
+              bottom: 25,
+            ),
+            child: Text(
+              'Total message count: ${_chat?.history.length ?? 0}',
+            ),
+          ),
         ],
       ),
     );
@@ -401,10 +411,10 @@ class _ChatWidgetState extends State<ChatWidget> {
 
     try {
       _generatedContent.add((image: null, text: message, fromUser: true));
-      var response = await _chat.sendMessage(
+      var response = await _chat?.sendMessage(
         Content.text(message),
       );
-      var text = response.text;
+      var text = response?.text;
       _generatedContent.add((image: null, text: text, fromUser: false));
 
       if (text == null) {
diff --git a/packages/firebase_vertexai/firebase_vertexai/lib/src/vertex_chat.dart b/packages/firebase_vertexai/firebase_vertexai/lib/src/vertex_chat.dart
@@ -25,21 +25,28 @@ import 'vertex_model.dart';
 /// Records messages sent and received in [history]. The history will always
 /// record the content from the first candidate in the
 /// [GenerateContentResponse], other candidates may be available on the returned
-/// response.
+/// response. The history is maintained and updated by the `google_generative_ai`
+/// package and reflects the most current state of the chat session.
 final class ChatSession {
   /// Creates a new chat session with the provided model.
+  ///
+  /// Initializes the chat session with the given [initialHistory], [SafetySetting],
+  /// and [GenerationConfig]. The history is passed to the `google_generative_ai`
+  /// package to start the chat session.
 
-  ChatSession._(this._history, List<SafetySetting>? _safetySettings,
-      GenerationConfig? _generationConfig, GenerativeModel _model)
+  ChatSession._(
+      List<Content> initialHistory,
+      List<SafetySetting>? _safetySettings,
+      GenerationConfig? _generationConfig,
+      GenerativeModel _model)
       : _googleAIChatSession = _model.googleAIModel.startChat(
-            history: _history.map((e) => e.toGoogleAI()).toList(),
+            history: initialHistory.map((e) => e.toGoogleAI()).toList(),
             safetySettings: _safetySettings != null
                 ? _safetySettings
                     .map((setting) => setting.toGoogleAI())
                     .toList()
                 : [],
             generationConfig: _generationConfig?.toGoogleAI());
-  final List<Content> _history;
 
   final google_ai.ChatSession _googleAIChatSession;
 
@@ -50,7 +57,12 @@ final class ChatSession {
   /// [sendMessageStream], these will not be reflected in the history.
   /// Messages without a candidate in the response are not recorded in history,
   /// including the message sent to the model.
-  Iterable<Content> get history => _history.skip(0);
+  ///
+  /// The history is maintained by the `google_generative_ai` package and reflects
+  /// the most current state of the chat session, ensuring that the history
+  /// returned is always up-to-date and consistent with the ongoing chat session.
+  Iterable<Content> get history =>
+      _googleAIChatSession.history.map((e) => e.toVertex());
 
   /// Sends [message] to the model as a continuation of the chat [history].
   ///
