feat(firebaseai): Added support for Server Prompt Template (#17767)

* init setup

* add the api

* Add chat page test case

* add template imagen generate

* add history placeholder

* more examples for server template

* create new models for template request

* working example with new architecture

* some tweak to clean up the PR

* Update server prompt api name and generateContentStream

* name updates and stream for chat history

* tweak UI a bit

* add media sample

* add function calling test

* testing imagen

* make inputs optional

* Add documentations

* add test and function calling

* make inputs required

* remove chat feature

* some gemini comments

* add documentations

* fix the template test

* fix pr comments

* update the test internal constructor and add more annotations

Author: cynthiajoan

packages/firebase_ai/firebase_ai/example/lib/main.dart

@@ -31,6 +31,7 @@ import 'pages/json_schema_page.dart';
 import 'pages/schema_page.dart';
 import 'pages/token_count_page.dart';
 import 'pages/video_page.dart';
+import 'pages/server_template_page.dart';
 
 void main() async {
   WidgetsFlutterBinding.ensureInitialized();
@@ -199,6 +200,11 @@ class _HomeScreenState extends State<HomeScreen> {
           model: currentModel,
           useVertexBackend: useVertexBackend,
         );
+      case 11:
+        return ServerTemplatePage(
+          title: 'Server Template',
+          useVertexBackend: useVertexBackend,
+        );
 
       default:
         // Fallback to the first page in case of an unexpected index
@@ -227,18 +233,15 @@ class _HomeScreenState extends State<HomeScreen> {
                   style: TextStyle(
                     fontSize: 12,
                     color: widget.useVertexBackend
-                        ? Theme.of(context)
-                            .colorScheme
-                            .onSurface
-                            .withValues(alpha: 0.7)
+                        ? Theme.of(context).colorScheme.onSurface.withAlpha(180)
                         : Theme.of(context).colorScheme.primary,
                   ),
                 ),
                 Switch(
                   value: widget.useVertexBackend,
                   onChanged: widget.onBackendChanged,
-                  activeTrackColor: Colors.green.withValues(alpha: 0.5),
-                  inactiveTrackColor: Colors.blueGrey.withValues(alpha: 0.5),
+                  activeTrackColor: Colors.green.withAlpha(128),
+                  inactiveTrackColor: Colors.blueGrey.withAlpha(128),
                   activeThumbColor: Colors.green,
                   inactiveThumbColor: Colors.blueGrey,
                 ),
@@ -251,7 +254,7 @@ class _HomeScreenState extends State<HomeScreen> {
                         : Theme.of(context)
                             .colorScheme
                             .onSurface
-                            .withValues(alpha: 0.7),
+                            .withAlpha(180),
                   ),
                 ),
               ],
@@ -273,7 +276,7 @@ class _HomeScreenState extends State<HomeScreen> {
         unselectedFontSize: 9,
         selectedItemColor: Theme.of(context).colorScheme.primary,
         unselectedItemColor: widget.useVertexBackend
-            ? Theme.of(context).colorScheme.onSurface.withValues(alpha: 0.7)
+            ? Theme.of(context).colorScheme.onSurface.withAlpha(180)
             : Colors.grey,
         items: const <BottomNavigationBarItem>[
           BottomNavigationBarItem(
@@ -333,6 +336,13 @@ class _HomeScreenState extends State<HomeScreen> {
             label: 'Live',
             tooltip: 'Live Stream',
           ),
+          BottomNavigationBarItem(
+            icon: Icon(
+              Icons.storage,
+            ),
+            label: 'Server',
+            tooltip: 'Server Template',
+          ),
         ],
         currentIndex: widget.selectedIndex,
         onTap: _onItemTapped,

packages/firebase_ai/firebase_ai/example/lib/pages/image_prompt_page.dart

@@ -11,7 +11,6 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
-
 import 'package:flutter/material.dart';
 import 'package:firebase_ai/firebase_ai.dart';
 import 'package:flutter/services.dart';
@@ -65,11 +64,13 @@ class _ImagePromptPageState extends State<ImagePromptPage> {
                   var content = _generatedContent[idx];
                   return MessageWidget(
                     text: content.text,
-                    image: Image.memory(
-                      content.imageBytes!,
-                      cacheWidth: 400,
-                      cacheHeight: 400,
-                    ),
+                    image: content.imageBytes == null
+                        ? null
+                        : Image.memory(
+                            content.imageBytes!,
+                            cacheWidth: 400,
+                            cacheHeight: 400,
+                          ),
                     isFromUser: content.fromUser ?? false,
                   );
                 },