Load chat messages as the user scrolls

homebase-chat/src/commonMain/kotlin/id/homebase/chat/conversationlist/ConversationListUiAction.kt

@@ -123,4 +123,6 @@ sealed interface ConversationListUiAction {
         val conversationId: Uuid,
         val imageBytes: ByteArray,
     ) : ConversationListUiAction
+
+    data class LoadMoreMessages(val conversationId: Uuid) : ConversationListUiAction
 }

homebase-chat/src/commonMain/kotlin/id/homebase/chat/conversationlist/ConversationListUiState.kt

@@ -47,6 +47,8 @@ data class MessageListUiState(
     val userDefaultReactions: ImmutableList<String> = persistentListOf(),
     val uploadProgress: ImmutableMap<Uuid, UploadStatus> = persistentMapOf(),
     val isLoadingMessages: Boolean = true,
+    val hasMoreMessages: Boolean = false,
+    val isLoadingMoreMessages: Boolean = false,
     val scrollPosition: ScrollPosition? = null,
     val fullScreenOverlay: FullScreenOverlay? = null,
     val replyToMessage: MessageUiModel? = null,

homebase-chat/src/commonMain/kotlin/id/homebase/chat/conversationlist/ConversationListViewModel.kt

@@ -385,6 +385,24 @@ class ConversationListViewModel(
                 }
             }
 
+            is ConversationListUiAction.LoadMoreMessages -> {
+                val conversationId = action.conversationId
+                if (_messagesUiState.value.isLoadingMoreMessages) return
+                _messagesUiState.update { it.copy(isLoadingMoreMessages = true) }
+                viewModelScope.launch {
+                    try {
+                        chatMessageStream.loadMoreMessages(conversationId)
+                    } finally {
+                        _messagesUiState.update {
+                            it.copy(
+                                isLoadingMoreMessages = false,
+                                hasMoreMessages = chatMessageStream.hasMoreMessages(conversationId)
+                            )
+                        }
+                    }
+                }
+            }
+
             is ConversationListUiAction.EditMessage -> {
                 viewModelScope.launch {
                     try {
@@ -1654,6 +1672,7 @@ class ConversationListViewModel(
                             _messagesUiState.update {
                                 it.copy(
                                     isLoadingMessages = false,
+                                    hasMoreMessages = chatMessageStream.hasMoreMessages(conversationId),
                                     messages = messagesModels.toPersistentList(),
                                     scrollPosition = if (indexOfMessageForScroll == null) {
                                         if (setInitialScroll) getScrollPosition(conversationId) else null

homebase-chat/src/commonMain/kotlin/id/homebase/chat/services/ChatMessageStream.kt

@@ -61,6 +61,8 @@ class ChatMessageStream(
     private val chatDrive = chatTargetDrive.alias
     private var isSyncing = false
     private val loadedConversations = mutableSetOf<Uuid>()
+    private val conversationCursors = mutableMapOf<Uuid, QueryBatchCursor>()
+    private val conversationHasMore = mutableMapOf<Uuid, Boolean>()
 
     init {
         scope.launch {
@@ -105,12 +107,27 @@ class ChatMessageStream(
     suspend fun loadConversation(conversationId: Uuid) {
         Logger.d("ChatMessageStream: loadConversation($conversationId)")
         loadedConversations += conversationId
-        val result = fetchMessages(conversationId)
-        Logger.d("ChatMessageStream: loadConversation($conversationId) → ${result.records.size} messages")
+        val result = fetchMessages(conversationId, limit = INITIAL_MESSAGE_LOAD)
+        Logger.d("ChatMessageStream: loadConversation($conversationId) → ${result.records.size} messages, hasMore=${result.hasMoreRows}")
+        conversationCursors[conversationId] = result.cursor
+        conversationHasMore[conversationId] = result.hasMoreRows
         conversationState.set(conversationId, result.records)
     }
 
-// ---------- EVENT HANDLING ----------
+    fun hasMoreMessages(conversationId: Uuid): Boolean = conversationHasMore[conversationId] == true
+
+    suspend fun loadMoreMessages(conversationId: Uuid) {
+        if (!hasMoreMessages(conversationId)) return
+        val cursor = conversationCursors[conversationId]
+        Logger.d("ChatMessageStream: loadMoreMessages($conversationId)")
+        val result = fetchMessages(conversationId, limit = SUBSEQUENT_MESSAGE_LOAD, cursor = cursor)
+        Logger.d("ChatMessageStream: loadMoreMessages($conversationId) → ${result.records.size} messages, hasMore=${result.hasMoreRows}")
+        conversationCursors[conversationId] = result.cursor
+        conversationHasMore[conversationId] = result.hasMoreRows
+        conversationState.upsert(conversationId, result.records)
+    }
+
+    // ---------- EVENT HANDLING ----------
 
     private suspend fun processIncrementalBatch(files: List<HomebaseFile>) {
         val messages =
@@ -126,8 +143,9 @@ class ChatMessageStream(
     private suspend fun refreshLoadedConversations() {
         Logger.d("ChatMessageStream: refreshLoadedConversations called, ${loadedConversations.size} active conversations")
         loadedConversations.forEach { conversationId ->
-            val result = fetchMessages(conversationId)
-            Logger.d("ChatMessageStream: fetchMessages($conversationId) → ${result.records.size} messages")
+            val result = fetchMessages(conversationId, limit = INITIAL_MESSAGE_LOAD)
+            conversationCursors[conversationId] = result.cursor
+            conversationHasMore[conversationId] = result.hasMoreRows
             conversationState.set(conversationId, result.records)
         }
     }
@@ -339,6 +357,8 @@ class ChatMessageStream(
     }
 
     companion object {
+        const val INITIAL_MESSAGE_LOAD = 50
+        const val SUBSEQUENT_MESSAGE_LOAD = 500
 
         private fun getDeliveryStatus(header: HomebaseFile): ChatDeliveryStatus {
 

homebase-chat/src/commonMain/kotlin/id/homebase/chat/widget/ConversationMessagesPane.kt

@@ -126,6 +126,35 @@ fun ConversationMessagesPane(
         }
     }
 
+    // Trigger load-more when user scrolls near the top (older messages)
+    LaunchedEffect(listState, uiState.hasMoreMessages, uiState.isLoadingMoreMessages) {
+        snapshotFlow { listState.firstVisibleItemIndex }
+            .distinctUntilChanged()
+            .collect { index ->
+                if (index <= 5 && uiState.hasMoreMessages && !uiState.isLoadingMoreMessages) {
+                    onUiAction(ConversationListUiAction.LoadMoreMessages(conversation.conversation.id))
+                }
+            }
+    }
+
+    // Compensate scroll position after older messages are prepended
+    var prevIsLoadingMore by remember { mutableStateOf(false) }
+    var itemCountAtLoadStart by remember { mutableStateOf(0) }
+    LaunchedEffect(uiState.isLoadingMoreMessages) {
+        if (uiState.isLoadingMoreMessages) {
+            itemCountAtLoadStart = listState.layoutInfo.totalItemsCount
+        } else if (prevIsLoadingMore) {
+            val added = listState.layoutInfo.totalItemsCount - itemCountAtLoadStart
+            if (added > 0) {
+                listState.scrollToItem(
+                    listState.firstVisibleItemIndex + added,
+                    listState.firstVisibleItemScrollOffset
+                )
+            }
+        }
+        prevIsLoadingMore = uiState.isLoadingMoreMessages
+    }
+
     val seen = remember(conversation.conversation.id) { mutableSetOf<Uuid>() }
     val messageIdByKey = remember(uiState.messages) {
         uiState.messages.associateNotNull { item ->