rewire chat history

Author: thatfiredev

ai/app/src/main/java/com/google/firebase/quickstart/ai/feature/text/ChatScreen.kt

@@ -38,6 +38,8 @@ import androidx.compose.ui.text.input.KeyboardCapitalization
 import androidx.compose.ui.unit.dp
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.lifecycle.viewmodel.compose.viewModel
+import com.google.firebase.vertexai.type.Content
+import com.google.firebase.vertexai.type.asTextOrNull
 import java.util.UUID
 import kotlinx.coroutines.launch
 import kotlinx.serialization.Serializable
@@ -51,7 +53,12 @@ data class ChatMessage(
     var text: String = "",
     val participant: Participant = Participant.USER,
     var isPending: Boolean = false
-)
+) {
+    constructor(content: Content) : this(
+        text = content.parts.first().asTextOrNull() ?: "",
+        participant = if (content.role == "user") Participant.USER else Participant.MODEL
+    )
+}
 
 @Serializable
 class ChatRoute(val sampleId: String)
@@ -69,7 +76,6 @@ fun ChatScreen(
     Column(
         modifier = Modifier
             .fillMaxSize()
-            .background(MaterialTheme.colorScheme.errorContainer)
     ) {
         ChatList(
             messages,

ai/app/src/main/java/com/google/firebase/quickstart/ai/feature/text/ChatViewModel.kt

@@ -23,26 +23,21 @@ class ChatViewModel(
     private val sample = FIREBASE_AI_SAMPLES.first { it.id == sampleId }
     val initialPrompt = sample.initialPrompt?.parts?.first()?.asTextOrNull().orEmpty()
 
-    private val _messageList: MutableList<ChatMessage> = sample.chatHistory.map { content ->
-        ChatMessage(
-            text = content.parts.first().asTextOrNull() ?: "",
-            participant = if (content.role == "user") Participant.USER else Participant.MODEL,
-            isPending = false
-        )
-    }.toMutableStateList()
+    private val _messageList: MutableList<ChatMessage> =
+        sample.chatHistory.map { ChatMessage(it) }.toMutableStateList()
     private val _messages = MutableStateFlow<List<ChatMessage>>(_messageList)
     val messages: StateFlow<List<ChatMessage>> =
         _messages
 
-
     private val generativeModel: GenerativeModel
     private val chat: Chat
 
     init {
         generativeModel = Firebase.vertexAI.generativeModel(
-            "gemini-2.0-flash"
+            modelName = "gemini-2.0-flash",
+            systemInstruction = sample.systemInstructions
         )
-        chat = generativeModel.startChat()
+        chat = generativeModel.startChat(sample.chatHistory)
     }
 
     fun sendMessage(userMessage: String) {

ai/app/src/main/java/com/google/firebase/quickstart/ai/ui/navigation/FirebaseAISamples.kt

@@ -9,10 +9,14 @@ val FIREBASE_AI_SAMPLES = listOf(
                 " travel tips for traveling.",
         navRoute = "chat",
         categories = listOf(Category.TEXT),
-        systemInstructions = "You are a Travel assistant. You will answer" +
-                " questions the user asks based on the information listed" +
-                " in Relevant Information. Do not hallucinate. Do not use" +
-                " the internet.",
+        systemInstructions = content {
+            text(
+                "You are a Travel assistant. You will answer" +
+                        " questions the user asks based on the information listed" +
+                        " in Relevant Information. Do not hallucinate. Do not use" +
+                        " the internet."
+            )
+        },
         chatHistory = listOf(
             content {
                 role = "user"

ai/app/src/main/java/com/google/firebase/quickstart/ai/ui/navigation/Sample.kt

@@ -23,6 +23,6 @@ data class Sample(
     val categories: List<Category>,
     // Optional parameters
     val initialPrompt: Content? = null,
-    val systemInstructions: String = "",
+    val systemInstructions: Content? = null,
     val chatHistory: List<Content> = emptyList(),
 )