Fix message loading

2026-04-19 17:41:08 +03:00
parent 769319f308
commit cab1ff93a4
1 changed files with 160 additions and 8 deletions
@@ -83,6 +83,7 @@ import de.connect2x.trixnity.client.store.TimelineEvent
 import de.connect2x.trixnity.client.store.eventId
 import de.connect2x.trixnity.core.model.RoomId
 import de.connect2x.trixnity.core.model.events.ClientEvent
+import de.connect2x.trixnity.core.model.events.m.FullyReadEventContent
 import de.connect2x.trixnity.core.model.events.m.room.AvatarEventContent
 import de.connect2x.trixnity.core.model.events.m.room.CanonicalAliasEventContent
 import de.connect2x.trixnity.core.model.events.m.room.HistoryVisibilityEventContent
@@ -100,6 +101,7 @@ import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.flatMapLatest
 import kotlinx.coroutines.flow.flowOf
+import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.launch
 import org.jsoup.Jsoup
 import org.jsoup.nodes.Element
@@ -116,6 +118,10 @@ import kotlin.math.roundToInt

 private const val WEBVIEW_HEIGHT_TITLE_PREFIX = "pd-height:"
 private const val MESSAGE_GROUP_WINDOW_MS = 5 * 60 * 1000L
+private const val TIMELINE_PAGE_SIZE = 50
+private const val TIMELINE_TOP_PREFETCH_THRESHOLD = 4
+private const val TIMELINE_BOTTOM_AUTOSCROLL_THRESHOLD = 3
+private const val MAX_INITIAL_UNREAD_SEARCH_LIMIT = 500
 private val TIMELINE_AVATAR_SIZE = 32.dp
 private val TIMELINE_AVATAR_START_PADDING = 8.dp
 private val TIMELINE_AVATAR_BOTTOM_PADDING = 8.dp
@@ -182,9 +188,14 @@ private val headingMetrics = mapOf(
@Composable
 fun Room(modifier: Modifier = Modifier, rid: String) {
    val roomId = remember(rid) { RoomId(rid) }
-    val limit = remember { MutableStateFlow(50) }
+    var requestedLimit by remember(roomId) { mutableStateOf(TIMELINE_PAGE_SIZE) }
+    val limit = remember(roomId) { MutableStateFlow(TIMELINE_PAGE_SIZE) }

-    val eventsFlow = remember(roomId) {
+    LaunchedEffect(requestedLimit) {
+        limit.value = requestedLimit
+    }
+
+    val eventsFlow = remember(roomId, client!!) {
        client!!.room
            .getLastTimelineEvents(roomId)
            .toFlowList(limit)
@@ -194,23 +205,105 @@ fun Room(modifier: Modifier = Modifier, rid: String) {
            }
    }
    val events by eventsFlow.collectAsState(initial = emptyList())
-    val currentUserId = remember { client!!.userId.toString() }
-    val timelineItems = remember(events, currentUserId) {
-        buildTimelineItems(events = events, currentUserId = currentUserId)
+
+    val readMarkerFlow = remember(roomId, client!!) {
+        client!!.room
+            .getAccountData(roomId, FullyReadEventContent::class)
+            .map { content -> ReadMarkerState.Ready(content?.eventId?.full) as ReadMarkerState }
+    }
+    val readMarkerState by readMarkerFlow.collectAsState(initial = ReadMarkerState.Loading)
+    val fullyReadEventId = (readMarkerState as? ReadMarkerState.Ready)?.eventId
+
+    val currentUserId = remember(client!!) { client!!.userId.toString() }
+    val timelineItems = remember(events, currentUserId, fullyReadEventId) {
+        buildTimelineItems(
+            events = events,
+            currentUserId = currentUserId,
+            fullyReadEventId = fullyReadEventId,
+        )
    }
    val latestTimelineKey = remember(timelineItems) {
        timelineItems.lastOrNull()?.latestKey()
    }

    val listState = rememberLazyListState()
+    var didInitialScroll by remember(roomId) { mutableStateOf(false) }
+    var lastAutoScrollTimelineKey by remember(roomId) { mutableStateOf<String?>(null) }
+
+    val isNearBottom by remember(timelineItems, listState) {
+        derivedStateOf {
+            val totalItems = listState.layoutInfo.totalItemsCount
+            if (totalItems == 0) return@derivedStateOf true
+
+            val lastVisibleIndex = listState.layoutInfo.visibleItemsInfo.lastOrNull()?.index
+                ?: return@derivedStateOf false
+            lastVisibleIndex >= totalItems - 1 - TIMELINE_BOTTOM_AUTOSCROLL_THRESHOLD
+        }
+    }
+
+    val shouldLoadOlder by remember(listState, didInitialScroll) {
+        derivedStateOf {
+            didInitialScroll &&
+                    listState.layoutInfo.totalItemsCount > 0 &&
+                    listState.firstVisibleItemIndex <= TIMELINE_TOP_PREFETCH_THRESHOLD
+        }
+    }

    Column(modifier) {
        var message by remember { mutableStateOf("") }

-        LaunchedEffect(latestTimelineKey) {
-            if (timelineItems.isNotEmpty()) {
-                listState.scrollToItem(timelineItems.lastIndex)
+        LaunchedEffect(timelineItems, readMarkerState, events.size, requestedLimit) {
+            if (didInitialScroll || timelineItems.isEmpty()) return@LaunchedEffect
+            if (readMarkerState is ReadMarkerState.Loading) return@LaunchedEffect
+
+            val readMarkerEventId = (readMarkerState as ReadMarkerState.Ready).eventId
+            val unreadDividerIndex = timelineItems.indexOfFirst { it is UnreadDividerItem }
+            if (unreadDividerIndex >= 0) {
+                listState.scrollToItem(unreadDividerIndex)
+                didInitialScroll = true
+                lastAutoScrollTimelineKey = latestTimelineKey
+                return@LaunchedEffect
            }
+
+            val readMarkerIsLoaded = readMarkerEventId != null &&
+                    events.any { it.eventId.full == readMarkerEventId }
+            val shouldSearchOlderForUnreadMarker = readMarkerEventId != null &&
+                    !readMarkerIsLoaded &&
+                    events.size >= requestedLimit &&
+                    requestedLimit < MAX_INITIAL_UNREAD_SEARCH_LIMIT
+
+            if (shouldSearchOlderForUnreadMarker) {
+                requestedLimit = (requestedLimit + TIMELINE_PAGE_SIZE)
+                    .coerceAtMost(MAX_INITIAL_UNREAD_SEARCH_LIMIT)
+                return@LaunchedEffect
+            }
+
+            listState.scrollToItem(timelineItems.lastIndex)
+            didInitialScroll = true
+            lastAutoScrollTimelineKey = latestTimelineKey
+        }
+
+        LaunchedEffect(shouldLoadOlder, events.size, requestedLimit) {
+            if (!shouldLoadOlder) return@LaunchedEffect
+            if (events.size < requestedLimit) return@LaunchedEffect
+
+            requestedLimit += TIMELINE_PAGE_SIZE
+        }
+
+        LaunchedEffect(latestTimelineKey) {
+            val currentLatestKey = latestTimelineKey ?: return@LaunchedEffect
+            val previousLatestKey = lastAutoScrollTimelineKey
+
+            if (!didInitialScroll) {
+                lastAutoScrollTimelineKey = currentLatestKey
+                return@LaunchedEffect
+            }
+
+            if (previousLatestKey != null && previousLatestKey != currentLatestKey && isNearBottom) {
+                listState.animateScrollToItem(timelineItems.lastIndex)
+            }
+
+            lastAutoScrollTimelineKey = currentLatestKey
        }

        val density = LocalDensity.current
@@ -298,6 +391,11 @@ fun Room(modifier: Modifier = Modifier, rid: String) {
    }
 }

+private sealed interface ReadMarkerState {
+    data object Loading : ReadMarkerState
+    data class Ready(val eventId: String?) : ReadMarkerState
+}
+
 private sealed interface TimelineUiItem {
    val key: String
 }
@@ -307,6 +405,10 @@ private data class DateDividerItem(
    val label: String,
 ) : TimelineUiItem

+private data class UnreadDividerItem(
+    override val key: String,
+) : TimelineUiItem
+
 private data class MessageGroupItem(
    override val key: String,
    val senderId: String?,
@@ -339,6 +441,7 @@ private data class SystemTimelineItem(
 private fun buildTimelineItems(
    events: List<TimelineEvent>,
    currentUserId: String,
+    fullyReadEventId: String?,
 ): List<TimelineUiItem> {
    if (events.isEmpty()) return emptyList()

@@ -347,6 +450,8 @@ private fun buildTimelineItems(

    var previousDayStartMs: Long? = null
    var lastMessageGroupIndex: Int? = null
+    var insertUnreadDividerBeforeNextMessage = false
+    var unreadDividerInserted = false

    for (event in chronologicalEvents) {
        val content = event.content?.getOrNull()
@@ -362,6 +467,17 @@ private fun buildTimelineItems(
            lastMessageGroupIndex = null
        }

+        if (
+            content is RoomMessageEventContent &&
+            insertUnreadDividerBeforeNextMessage &&
+            !unreadDividerInserted
+        ) {
+            items += UnreadDividerItem(key = "unread:$fullyReadEventId")
+            unreadDividerInserted = true
+            insertUnreadDividerBeforeNextMessage = false
+            lastMessageGroupIndex = null
+        }
+
        when {
            content == null -> {
                items += SystemTimelineItem(
@@ -430,6 +546,11 @@ private fun buildTimelineItems(
                lastMessageGroupIndex = null
            }
        }
+
+        if (!unreadDividerInserted && fullyReadEventId != null && event.eventId.full == fullyReadEventId) {
+            insertUnreadDividerBeforeNextMessage = true
+            lastMessageGroupIndex = null
+        }
    }

    return items
@@ -442,6 +563,7 @@ private fun TimelineItem(
 ) {
    when (item) {
        is DateDividerItem -> DateDivider(item)
+        is UnreadDividerItem -> UnreadDivider()
        is MessageGroupItem -> MessageGroupRow(
            group = item,
            hideInlineAvatar = pinnedAvatarGroupKey == item.key,
@@ -473,6 +595,36 @@ private fun DateDivider(item: DateDividerItem) {
    }
 }

+@Composable
+private fun UnreadDivider() {
+    Row(
+        modifier = Modifier
+            .fillMaxWidth()
+            .padding(horizontal = 12.dp, vertical = 8.dp),
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        Box(
+            modifier = Modifier
+                .height(1.dp)
+                .weight(1f)
+                .background(MaterialTheme.colorScheme.primary.copy(alpha = 0.45f)),
+        )
+        Text(
+            text = "Unread messages",
+            modifier = Modifier.padding(horizontal = 8.dp),
+            style = MaterialTheme.typography.labelSmall,
+            color = MaterialTheme.colorScheme.primary,
+            fontWeight = FontWeight.SemiBold,
+        )
+        Box(
+            modifier = Modifier
+                .height(1.dp)
+                .weight(1f)
+                .background(MaterialTheme.colorScheme.primary.copy(alpha = 0.45f)),
+        )
+    }
+}
+
@Composable
 private fun SystemEventRow(item: SystemTimelineItem) {
    Text(