feat(chat): typing indicator

Debounced typing flag (typing:{uid:ts}) on the conversation doc, cleared on stop/send/
leave; partner sees 'typing…' with a ~6s TTL safety net (ticker-driven auto-hide). Rules
allow members to write the typing field. Live verification pending the Phase B deploy.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/src/main/java/app/closer/data/remote/FirestoreConversationDataSource.kt

@@ -192,6 +192,26 @@ class FirestoreConversationDataSource @Inject constructor(
         }
     }
 
+    /** Fire-and-forget typing flag on the conversation doc (ephemeral; cleared on stop/send/leave). */
+    fun setTyping(coupleId: String, conversationId: String, userId: String, typing: Boolean) {
+        val ref = conversationsRef(coupleId).document(conversationId)
+        val value = if (typing) FieldValue.serverTimestamp() else FieldValue.delete()
+        ref.update(mapOf("typing.$userId" to value)).addOnFailureListener { /* best-effort */ }
+    }
+
+    /** Emits the partner's latest typing timestamp (0 if not typing). */
+    fun observePartnerTyping(coupleId: String, conversationId: String, currentUserId: String): Flow<Long> = callbackFlow {
+        val listener = conversationsRef(coupleId).document(conversationId)
+            .addSnapshotListener { snap, err ->
+                if (err != null || snap == null) return@addSnapshotListener
+                @Suppress("UNCHECKED_CAST")
+                val typing = (snap.get("typing") as? Map<String, com.google.firebase.Timestamp>).orEmpty()
+                val at = typing.filterKeys { it != currentUserId }.values.maxOfOrNull { it.toDate().time } ?: 0L
+                trySend(at)
+            }
+        awaitClose { listener.remove() }
+    }
+
     /** Emits the partner's most recent read timestamp for this conversation (0 if never read). */
     fun observePartnerReadAt(coupleId: String, conversationId: String, currentUserId: String): Flow<Long> = callbackFlow {
         val listener = conversationsRef(coupleId).document(conversationId)

app/src/main/java/app/closer/data/repository/ConversationRepositoryImpl.kt

@@ -31,6 +31,12 @@ class ConversationRepositoryImpl @Inject constructor(
     override fun observePartnerReadAt(coupleId: String, conversationId: String, currentUserId: String): Flow<Long> =
         dataSource.observePartnerReadAt(coupleId, conversationId, currentUserId)
 
+    override fun setTyping(coupleId: String, conversationId: String, userId: String, typing: Boolean) =
+        dataSource.setTyping(coupleId, conversationId, userId, typing)
+
+    override fun observePartnerTyping(coupleId: String, conversationId: String, currentUserId: String): Flow<Long> =
+        dataSource.observePartnerTyping(coupleId, conversationId, currentUserId)
+
     override suspend fun sendMessage(coupleId: String, conversationId: String, userId: String, text: String) =
         dataSource.sendMessage(coupleId, conversationId, userId, text)
 

app/src/main/java/app/closer/domain/repository/ConversationRepository.kt

@@ -11,6 +11,8 @@ interface ConversationRepository {
     suspend fun markRead(coupleId: String, conversationId: String, userId: String)
     fun observeMessages(coupleId: String, conversationId: String, limit: Int): Flow<List<QuestionMessage>>
     fun observePartnerReadAt(coupleId: String, conversationId: String, currentUserId: String): Flow<Long>
+    fun setTyping(coupleId: String, conversationId: String, userId: String, typing: Boolean)
+    fun observePartnerTyping(coupleId: String, conversationId: String, currentUserId: String): Flow<Long>
     suspend fun sendMessage(coupleId: String, conversationId: String, userId: String, text: String)
     suspend fun sendImageMessage(coupleId: String, conversationId: String, userId: String, imageBytes: ByteArray)
     suspend fun sendVoiceMessage(coupleId: String, conversationId: String, userId: String, audioBytes: ByteArray, durationMs: Long)

app/src/main/java/app/closer/ui/messages/ConversationScreen.kt

@@ -158,6 +158,15 @@ fun ConversationScreen(
                 }
             }
 
+            if (state.partnerTyping) {
+                Text(
+                    text = "typing…",
+                    style = MaterialTheme.typography.labelMedium,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant.copy(alpha = 0.7f),
+                    modifier = Modifier.padding(start = 20.dp, bottom = 2.dp)
+                )
+            }
+
             state.pendingMedia.forEach { pm ->
                 PendingMediaChip(
                     pending = pm,

app/src/main/java/app/closer/ui/messages/ConversationViewModel.kt

@@ -13,14 +13,19 @@ import app.closer.notifications.ActiveThreadMonitor
 import com.google.firebase.auth.FirebaseAuth
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.Job
 import kotlinx.coroutines.flow.MutableSharedFlow
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.SharedFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asSharedFlow
 import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.distinctUntilChanged
 import kotlinx.coroutines.flow.flatMapLatest
+import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.flow.update
+import kotlinx.coroutines.delay
 import kotlinx.coroutines.launch
 import java.util.UUID
 import javax.inject.Inject
@@ -35,6 +40,7 @@ data class ConversationUiState(
     val pendingMedia: List<PendingMedia> = emptyList(),
     val canLoadMore: Boolean = false,
     val partnerReadAt: Long = 0L,
+    val partnerTyping: Boolean = false,
     val messageInput: String = "",
     val isLoading: Boolean = true
 )
@@ -75,6 +81,7 @@ class ConversationViewModel @Inject constructor(
     override fun onCleared() {
         super.onCleared()
         activeThreadMonitor.leave(conversationId)
+        stopTyping() // fire-and-forget; clears our typing flag when leaving
     }
 
     private fun load() {
@@ -115,9 +122,42 @@ class ConversationViewModel @Inject constructor(
                 repository.observePartnerReadAt(coupleId, conversationId, currentUserId)
                     .collect { readAt -> _uiState.update { it.copy(partnerReadAt = readAt) } }
             }
+
+            // Partner typing: combine the typing timestamp with a ticker so it auto-hides after ~6s
+            // even if the partner's "stop" write never arrives (crash safety net).
+            launch {
+                combine(
+                    repository.observePartnerTyping(coupleId, conversationId, currentUserId),
+                    flow { while (true) { emit(Unit); delay(2000) } }
+                ) { typingAt, _ -> typingAt > 0 && System.currentTimeMillis() - typingAt < TYPING_TTL_MS }
+                    .distinctUntilChanged()
+                    .collect { typing -> _uiState.update { it.copy(partnerTyping = typing) } }
+            }
         }
     }
 
+    private var typingStopJob: Job? = null
+    private var lastTypingPingAt = 0L
+
+    private fun onUserTyping() {
+        val now = System.currentTimeMillis()
+        if (now - lastTypingPingAt > 1500) {
+            lastTypingPingAt = now
+            repository.setTyping(coupleId, conversationId, currentUserId, true)
+        }
+        typingStopJob?.cancel()
+        typingStopJob = viewModelScope.launch {
+            delay(3000)
+            stopTyping()
+        }
+    }
+
+    private fun stopTyping() {
+        typingStopJob?.cancel()
+        lastTypingPingAt = 0L
+        repository.setTyping(coupleId, conversationId, currentUserId, false)
+    }
+
     /** Grow the live window by another page (triggered when scrolled to the top). */
     fun loadOlderMessages() {
         if (_uiState.value.canLoadMore) messageLimit.update { it + PAGE_SIZE }
@@ -125,12 +165,14 @@ class ConversationViewModel @Inject constructor(
 
     fun updateMessageInput(text: String) {
         _uiState.update { it.copy(messageInput = text.take(MAX_MESSAGE_LENGTH)) }
+        if (text.isNotBlank()) onUserTyping()
     }
 
     fun sendMessage() {
         val text = _uiState.value.messageInput.trim()
         if (text.isBlank() || currentUserId.isEmpty()) return
         _uiState.update { it.copy(messageInput = "") }
+        stopTyping()
         viewModelScope.launch {
             runCatching { repository.sendMessage(coupleId, conversationId, currentUserId, text) }
                 .onFailure { _events.tryEmit("Couldn't send message. Check your connection.") }
@@ -209,5 +251,6 @@ class ConversationViewModel @Inject constructor(
     companion object {
         const val MAX_MESSAGE_LENGTH = 2000
         const val PAGE_SIZE = 50
+        private const val TYPING_TTL_MS = 6000L
     }
 }

firestore.rules

@@ -422,7 +422,7 @@ service cloud.firestore {
         // last-message preview must be ciphertext (encrypted on-device before write).
         allow write: if isCouplesMember(coupleId)
           && request.resource.data.keys().hasOnly(
-               ['type', 'questionId', 'createdAt', 'lastMessageAt', 'lastMessagePreview', 'lastMessageSenderId', 'reads'])
+               ['type', 'questionId', 'createdAt', 'lastMessageAt', 'lastMessagePreview', 'lastMessageSenderId', 'reads', 'typing'])
           && (!('lastMessagePreview' in request.resource.data)
                || isCiphertext(request.resource.data.lastMessagePreview));