offline: Keep persisted channel lastMessageAt consistent with its latest message

stream-chat-android-compose-sample/src/androidTestE2eDebug/kotlin/io/getstream/chat/android/compose/tests/MessageDeliveryStatusTests.kt

@@ -80,7 +80,9 @@ class MessageDeliveryStatusTests : StreamTestCase() {
             userRobot.login().openChannel()
         }
         step("AND user successfully sends a new message") {
-            userRobot.sendMessage(sampleText)
+            userRobot
+                .sendMessage(sampleText)
+                .assertMessageDeliveryStatus(MessageDeliveryStatus.SENT) // await for message to be successfully sent
         }
         step("WHEN participant reads the user's message") {
             participantRobot.readMessage()

stream-chat-android-offline/src/main/java/io/getstream/chat/android/offline/repository/domain/channel/internal/ChannelMapper.kt

@@ -16,8 +16,10 @@
 
 package io.getstream.chat.android.offline.repository.domain.channel.internal
 
+import io.getstream.chat.android.client.extensions.getCreatedAtOrNull
 import io.getstream.chat.android.client.extensions.internal.lastMessage
 import io.getstream.chat.android.client.extensions.syncUnreadCountWithReads
+import io.getstream.chat.android.core.utils.date.max
 import io.getstream.chat.android.models.Channel
 import io.getstream.chat.android.models.ChannelUserRead
 import io.getstream.chat.android.models.DraftMessage
@@ -53,7 +55,7 @@ internal fun Channel.toEntity(): ChannelEntity {
         memberCount = memberCount,
         reads = read.map(ChannelUserRead::toEntity).associateBy(ChannelUserReadEntity::userId).toMutableMap(),
         lastMessageId = lastMessage?.id,
-        lastMessageAt = lastMessageAt,
+        lastMessageAt = max(lastMessageAt, lastMessage?.getCreatedAtOrNull()),
         createdByUserId = createdBy.id,
         watcherIds = watchers.map(User::id),
         watcherCount = watcherCount,

stream-chat-android-offline/src/test/java/io/getstream/chat/android/offline/repository/domain/channel/internal/ChannelMapperTest.kt

@@ -37,6 +37,7 @@ import io.getstream.chat.android.randomUser
 import kotlinx.coroutines.test.runTest
 import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.Test
+import java.util.Date
 
 internal class ChannelMapperTest {
 
@@ -86,7 +87,7 @@ internal class ChannelMapperTest {
             memberCount = channel.memberCount,
             reads = reads.map { it.toEntity() }.associateBy { it.userId }.toMutableMap(),
             lastMessageId = lastMessage.id,
-            lastMessageAt = channel.lastMessageAt,
+            lastMessageAt = listOfNotNull(channel.lastMessageAt, lastMessage.createdAt).maxOrNull(),
             createdByUserId = createdByUser.id,
             watcherIds = watchers.map { it.id },
             watcherCount = channel.watcherCount,
@@ -102,6 +103,48 @@ internal class ChannelMapperTest {
         assertEquals(expectedChannelEntity, result)
     }
 
+    @Test
+    fun `toEntity should advance lastMessageAt to the newest message when the stored value is stale`() = runTest {
+        val newest = randomMessage(
+            createdAt = Date(2000),
+            createdLocallyAt = null,
+            parentId = null,
+            deletedAt = null,
+            deletedForMe = false,
+        )
+        val channel = randomChannel(messages = listOf(newest), lastMessageAt = Date(1000))
+
+        val entity = channel.toEntity()
+
+        assertEquals(Date(2000), entity.lastMessageAt)
+        assertEquals(newest.id, entity.lastMessageId)
+    }
+
+    @Test
+    fun `toEntity should keep lastMessageAt when it is newer than the last message`() = runTest {
+        val older = randomMessage(
+            createdAt = Date(1000),
+            createdLocallyAt = null,
+            parentId = null,
+            deletedAt = null,
+            deletedForMe = false,
+        )
+        val channel = randomChannel(messages = listOf(older), lastMessageAt = Date(3000))
+
+        val entity = channel.toEntity()
+
+        assertEquals(Date(3000), entity.lastMessageAt)
+    }
+
+    @Test
+    fun `toEntity should keep lastMessageAt when there is no last message`() = runTest {
+        val channel = randomChannel(messages = emptyList(), lastMessageAt = Date(1000))
+
+        val entity = channel.toEntity()
+
+        assertEquals(Date(1000), entity.lastMessageAt)
+    }
+
     @Test
     @Suppress("LongMethod")
     fun `Should map ChannelEntity to Channel correctly`() = runTest {