From 32916444e5ea9e69e32b688c13bbc2d59b51e689 Mon Sep 17 00:00:00 2001
From: Benoit Marty <benoitm@element.io>
Date: Tue, 6 May 2025 14:41:34 +0200
Subject: [PATCH] Fix read receipt behavior when the timeline is opened.
 (#4679)

* Use Timber instead of println

* Fix ReadReceipt not sent when new event is received:
- filter Virtual item regarding typing to compute NewEventState
- always scroll, since the latest event is always the typing notification (but with 0 height). This triggers the sending of RR.

* Improve the fix to fix regression detected by unit tests.

* Remove unnecessary parenthesis

* Document parameter.
---
 .../messages/impl/timeline/TimelinePresenter.kt  |  8 ++++++--
 .../messages/impl/timeline/TimelineView.kt       | 16 +++++++++++-----
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/TimelinePresenter.kt b/features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/TimelinePresenter.kt
index cc6c9c5860..3be27fe7d0 100644
--- a/features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/TimelinePresenter.kt
+++ b/features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/TimelinePresenter.kt
@@ -28,6 +28,7 @@ import io.element.android.features.messages.impl.timeline.factories.TimelineItem
 import io.element.android.features.messages.impl.timeline.factories.TimelineItemsFactoryConfig
 import io.element.android.features.messages.impl.timeline.model.NewEventState
 import io.element.android.features.messages.impl.timeline.model.TimelineItem
+import io.element.android.features.messages.impl.timeline.model.virtual.TimelineItemTypingNotificationModel
 import io.element.android.features.messages.impl.typing.TypingNotificationState
 import io.element.android.features.messages.impl.voicemessages.timeline.RedactedVoiceMessageManager
 import io.element.android.features.poll.api.actions.EndPollAction
@@ -131,7 +132,7 @@ class TimelinePresenter @AssistedInject constructor(
                         if (event.firstIndex == 0) {
                             newEventState.value = NewEventState.None
                         }
-                        println("## sendReadReceiptIfNeeded firstVisibleIndex: ${event.firstIndex}")
+                        Timber.d("## sendReadReceiptIfNeeded firstVisibleIndex: ${event.firstIndex}")
                         appScope.sendReadReceiptIfNeeded(
                             firstVisibleIndex = event.firstIndex,
                             timelineItems = timelineItems,
@@ -278,7 +279,10 @@ class TimelinePresenter @AssistedInject constructor(
         if (newEventState.value == NewEventState.FromMe) {
             return@withContext
         }
-        val newMostRecentItem = timelineItems.firstOrNull()
+        val newMostRecentItem = timelineItems.firstOrNull {
+            // Ignore typing item
+            (it as? TimelineItem.Virtual)?.model !is TimelineItemTypingNotificationModel
+        }
         val prevMostRecentItemIdValue = prevMostRecentItemId.value
         val newMostRecentItemId = newMostRecentItem?.identifier()
         val hasNewEvent = prevMostRecentItemIdValue != null &&
diff --git a/features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/TimelineView.kt b/features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/TimelineView.kt
index 6e677e5984..c64eec9bee 100644
--- a/features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/TimelineView.kt
+++ b/features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/TimelineView.kt
@@ -286,11 +286,16 @@ private fun BoxScope.TimelineScrollHelper(
     }
     var jumpToLiveHandled by remember { mutableStateOf(true) }
 
-    fun scrollToBottom() {
+    /**
+     * @param force If true, scroll to the bottom even if the user is already seeing the most recent item.
+     * This fixes the issue where the user is seeing typing notification and so the read receipt is not sent
+     * when a new message comes in.
+     */
+    fun scrollToBottom(force: Boolean) {
         coroutineScope.launch {
             if (lazyListState.firstVisibleItemIndex > 10) {
                 lazyListState.scrollToItem(0)
-            } else if (lazyListState.firstVisibleItemIndex != 0) {
+            } else if (force || lazyListState.firstVisibleItemIndex != 0) {
                 lazyListState.animateScrollToItem(0)
             }
         }
@@ -298,7 +303,7 @@ private fun BoxScope.TimelineScrollHelper(
 
     fun jumpToBottom() {
         if (isLive) {
-            scrollToBottom()
+            scrollToBottom(force = false)
         } else {
             jumpToLiveHandled = false
             onJumpToLive()
@@ -321,9 +326,10 @@ private fun BoxScope.TimelineScrollHelper(
     }
 
     LaunchedEffect(canAutoScroll, newEventState) {
-        val shouldScrollToBottom = isScrollFinished && (canAutoScroll || newEventState == NewEventState.FromMe)
+        val shouldScrollToBottom = isScrollFinished &&
+            (canAutoScroll && newEventState == NewEventState.FromOther || newEventState == NewEventState.FromMe)
         if (shouldScrollToBottom) {
-            scrollToBottom()
+            scrollToBottom(force = true)
         }
     }