Merge pull request #7864 from element-hq/feature/fga/timeline-multi-forward

Initial implementation of timeline multi forward

appnav/src/main/kotlin/io/element/android/appnav/room/joined/JoinedRoomLoadedFlowNode.kt

@@ -201,7 +201,7 @@ class JoinedRoomLoadedFlowNode(
                 } else {
                     (graph as TimelineBindings).timelineProvider
                 }
-                val params = ForwardEntryPoint.Params(navTarget.eventId, timelineProvider)
+                val params = ForwardEntryPoint.Params(listOf(navTarget.eventId), timelineProvider)
                 val callback = object : ForwardEntryPoint.Callback {
                     override fun onDone(roomIds: List<RoomId>) {
                         backstack.pop()

features/forward/api/src/main/kotlin/io/element/android/features/forward/api/ForwardEntryPoint.kt

@@ -23,7 +23,7 @@ interface ForwardEntryPoint : FeatureEntryPoint {
     }
 
     data class Params(
-        val eventId: EventId,
+        val eventIds: List<EventId>,
         val timelineProvider: TimelineProvider,
     ) : NodeInputs
 

features/forward/impl/src/main/kotlin/io/element/android/features/forward/impl/DefaultForwardEntryPoint.kt

@@ -27,7 +27,7 @@ class DefaultForwardEntryPoint : ForwardEntryPoint {
             buildContext = buildContext,
             plugins = listOf(
                 ForwardMessagesNode.Inputs(
-                    eventId = params.eventId,
+                    eventIds = params.eventIds,
                     timelineProvider = params.timelineProvider,
                 ),
                 callback,

features/forward/impl/src/main/kotlin/io/element/android/features/forward/impl/ForwardMessagesNode.kt

@@ -54,13 +54,13 @@ class ForwardMessagesNode(
     object NavTarget : Parcelable
 
     data class Inputs(
-        val eventId: EventId,
+        val eventIds: List<EventId>,
         val timelineProvider: TimelineProvider,
     ) : NodeInputs
 
     private val inputs = inputs<Inputs>()
     private val callback: ForwardEntryPoint.Callback = callback()
-    private val presenter = presenterFactory.create(inputs.eventId.value, inputs.timelineProvider)
+    private val presenter = presenterFactory.create(inputs.eventIds, inputs.timelineProvider)
 
     override fun resolve(navTarget: NavTarget, buildContext: BuildContext): Node {
         val callback = object : RoomSelectEntryPoint.Callback {

features/forward/impl/src/main/kotlin/io/element/android/features/forward/impl/ForwardMessagesPresenter.kt

@@ -28,22 +28,20 @@ import timber.log.Timber
 
 @AssistedInject
 class ForwardMessagesPresenter(
-    @Assisted eventId: String,
+    @Assisted private val eventIds: List<EventId>,
     @Assisted private val timelineProvider: TimelineProvider,
     @SessionCoroutineScope
     private val sessionCoroutineScope: CoroutineScope,
 ) : Presenter<ForwardMessagesState> {
-    private val eventId: EventId = EventId(eventId)
-
     @AssistedFactory
     fun interface Factory {
-        fun create(eventId: String, timelineProvider: TimelineProvider): ForwardMessagesPresenter
+        fun create(eventIds: List<EventId>, timelineProvider: TimelineProvider): ForwardMessagesPresenter
     }
 
     private val forwardingActionState: MutableState<AsyncAction<List<RoomId>>> = mutableStateOf(AsyncAction.Uninitialized)
 
     fun onRoomSelected(roomIds: List<RoomId>) {
-        sessionCoroutineScope.forwardEvent(eventId, roomIds)
+        sessionCoroutineScope.forwardEvents(eventIds, roomIds)
     }
 
     @Composable
@@ -60,14 +58,14 @@ class ForwardMessagesPresenter(
         )
     }
 
-    private fun CoroutineScope.forwardEvent(
-        eventId: EventId,
+    private fun CoroutineScope.forwardEvents(
+        eventIds: List<EventId>,
         roomIds: List<RoomId>,
     ) = launch {
         suspend {
-            timelineProvider.getActiveTimeline().forwardEvent(eventId, roomIds)
+            timelineProvider.getActiveTimeline().forwardEvents(eventIds, roomIds)
                 .onFailure {
-                    Timber.e(it, "Error while forwarding event")
+                    Timber.e(it, "Error while forwarding events")
                 }
                 .getOrThrow()
             roomIds

features/forward/impl/src/test/kotlin/io/element/android/features/forward/impl/DefaultForwardEntryPointTest.kt

@@ -47,7 +47,7 @@ class DefaultForwardEntryPointTest {
             override fun onDone(roomIds: List<RoomId>) = lambdaError()
         }
         val params = ForwardEntryPoint.Params(
-            eventId = AN_EVENT_ID,
+            eventIds = listOf(AN_EVENT_ID),
             timelineProvider = FakeTimelineProvider(),
         )
         val result = entryPoint.createNode(
@@ -59,7 +59,7 @@ class DefaultForwardEntryPointTest {
         assertThat(result).isInstanceOf(ForwardMessagesNode::class.java)
         assertThat(result.plugins).contains(
             ForwardMessagesNode.Inputs(
-                eventId = params.eventId,
+                eventIds = params.eventIds,
                 timelineProvider = params.timelineProvider,
             )
         )

features/forward/impl/src/test/kotlin/io/element/android/features/forward/impl/ForwardMessagesPresenterTest.kt

@@ -44,11 +44,11 @@ class ForwardMessagesPresenterTest {
 
     @Test
     fun `present - forward successful`() = runTest {
-        val forwardEventLambda = lambdaRecorder { _: EventId, _: List<RoomId> ->
+        val forwardEventsLambda = lambdaRecorder { _: List<EventId>, _: List<RoomId> ->
             Result.success(Unit)
         }
         val timeline = FakeTimeline().apply {
-            this.forwardEventLambda = forwardEventLambda
+            this.forwardEventsLambda = forwardEventsLambda
         }
         val room = FakeJoinedRoom(liveTimeline = timeline)
         val presenter = createForwardMessagesPresenter(fakeRoom = room)
@@ -62,17 +62,17 @@ class ForwardMessagesPresenterTest {
             assertThat(forwardingState.forwardAction.isLoading()).isTrue()
             val successfulForwardState = awaitItem()
             assertThat(successfulForwardState.forwardAction).isEqualTo(AsyncAction.Success(listOf(summary.roomId)))
-            forwardEventLambda.assertions().isCalledOnce()
+            forwardEventsLambda.assertions().isCalledOnce()
         }
     }
 
     @Test
     fun `present - select a room and forward failed, then clear`() = runTest {
-        val forwardEventLambda = lambdaRecorder { _: EventId, _: List<RoomId> ->
+        val forwardEventsLambda = lambdaRecorder { _: List<EventId>, _: List<RoomId> ->
             Result.failure<Unit>(IllegalStateException("error"))
         }
         val timeline = FakeTimeline().apply {
-            this.forwardEventLambda = forwardEventLambda
+            this.forwardEventsLambda = forwardEventsLambda
         }
         val room = FakeJoinedRoom(liveTimeline = timeline)
         val presenter = createForwardMessagesPresenter(fakeRoom = room)
@@ -88,16 +88,16 @@ class ForwardMessagesPresenterTest {
             // Then clear error
             failedForwardState.eventSink(ForwardMessagesEvent.ClearError)
             assertThat(awaitItem().forwardAction.isUninitialized()).isTrue()
-            forwardEventLambda.assertions().isCalledOnce()
+            forwardEventsLambda.assertions().isCalledOnce()
         }
     }
 }
 
 fun TestScope.createForwardMessagesPresenter(
-    eventId: EventId = AN_EVENT_ID,
+    eventIds: List<EventId> = listOf(AN_EVENT_ID),
     fakeRoom: FakeJoinedRoom = FakeJoinedRoom(),
 ) = ForwardMessagesPresenter(
-    eventId = eventId.value,
+    eventIds = eventIds,
     timelineProvider = LiveTimelineProvider(fakeRoom),
     sessionCoroutineScope = this,
 )

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/MessagesEvent.kt

@@ -23,6 +23,7 @@ sealed interface MessagesEvent {
     data object StopLiveLocationShare : MessagesEvent
     data object ShowLiveLocationShare : MessagesEvent
     data object MarkAsFullyReadAndExit : MessagesEvent
+    data object ConfirmSelectionAction : MessagesEvent
 }
 
 enum class InviteDialogAction {

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/MessagesFlowNode.kt

@@ -181,7 +181,7 @@ class MessagesFlowNode(
 
         @Parcelize
         data class ForwardEvent(
-            val eventId: EventId,
+            val eventIds: List<EventId>,
             @IgnoredOnParcel
             val timelineProvider: TimelineProvider? = null,
         ) : NavTarget
@@ -306,8 +306,8 @@ class MessagesFlowNode(
                         backstack.push(NavTarget.EventDebugInfo(eventId, debugInfo))
                     }
 
-                    override fun forwardEvent(eventId: EventId, timelineProvider: TimelineProvider) {
-                        backstack.push(NavTarget.ForwardEvent(eventId, timelineProvider))
+                    override fun forwardEvents(eventIds: List<EventId>, timelineProvider: TimelineProvider) {
+                        backstack.push(NavTarget.ForwardEvent(eventIds, timelineProvider))
                     }
 
                     override fun navigateToReportMessage(eventId: EventId, senderId: UserId) {
@@ -464,7 +464,7 @@ class MessagesFlowNode(
             is NavTarget.ForwardEvent -> {
                 // If no timeline provider is received, assume the live timeline should be used
                 val timelineProvider = navTarget.timelineProvider ?: timelineController
-                val params = ForwardEntryPoint.Params(navTarget.eventId, timelineProvider)
+                val params = ForwardEntryPoint.Params(navTarget.eventIds, timelineProvider)
                 val callback = object : ForwardEntryPoint.Callback {
                     override fun onDone(roomIds: List<RoomId>) {
                         backstack.pop()
@@ -551,7 +551,7 @@ class MessagesFlowNode(
                     }
 
                     override fun handleForwardEventClick(eventId: EventId, timelineProvider: TimelineProvider) {
-                        backstack.push(NavTarget.ForwardEvent(eventId = eventId, timelineProvider = timelineProvider))
+                        backstack.push(NavTarget.ForwardEvent(eventIds = listOf(eventId), timelineProvider = timelineProvider))
                     }
 
                     override fun navigateToThread(threadRootId: ThreadId) {
@@ -617,8 +617,8 @@ class MessagesFlowNode(
                         backstack.push(NavTarget.EventDebugInfo(eventId, debugInfo))
                     }
 
-                    override fun handleForwardEventClick(eventId: EventId, timelineProvider: TimelineProvider) {
-                        backstack.push(NavTarget.ForwardEvent(eventId, timelineProvider))
+                    override fun handleForwardEventClick(eventIds: List<EventId>, timelineProvider: TimelineProvider) {
+                        backstack.push(NavTarget.ForwardEvent(eventIds, timelineProvider))
                     }
 
                     override fun navigateToReportMessage(eventId: EventId, senderId: UserId) {

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/MessagesNavigator.kt

@@ -19,7 +19,7 @@ import kotlinx.collections.immutable.ImmutableList
 
 interface MessagesNavigator {
     fun navigateToEventDebugInfo(eventId: EventId?, debugInfo: TimelineItemDebugInfo)
-    fun forwardEvent(eventId: EventId, timelineProvider: TimelineProvider)
+    fun forwardEvents(eventIds: List<EventId>, timelineProvider: TimelineProvider)
     fun navigateToReportMessage(eventId: EventId, senderId: UserId)
     fun navigateToEditPoll(eventId: EventId)
     fun navigateToPreviewAttachments(attachments: ImmutableList<Attachment>, inReplyToEventId: EventId?)

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/MessagesNode.kt

@@ -138,7 +138,7 @@ class MessagesNode(
         fun navigateToRoomMemberDetails(userId: UserId)
         fun handlePermalinkClick(data: PermalinkData)
         fun navigateToEventDebugInfo(eventId: EventId?, debugInfo: TimelineItemDebugInfo)
-        fun forwardEvent(eventId: EventId, timelineProvider: TimelineProvider)
+        fun forwardEvents(eventIds: List<EventId>, timelineProvider: TimelineProvider)
         fun navigateToReportMessage(eventId: EventId, senderId: UserId)
         fun navigateToSendLocation()
         fun navigateToCreatePoll()
@@ -221,8 +221,8 @@ class MessagesNode(
         callback.navigateToEventDebugInfo(eventId, debugInfo)
     }
 
-    override fun forwardEvent(eventId: EventId, timelineProvider: TimelineProvider) {
-        callback.forwardEvent(eventId, timelineProvider)
+    override fun forwardEvents(eventIds: List<EventId>, timelineProvider: TimelineProvider) {
+        callback.forwardEvents(eventIds, timelineProvider)
     }
 
     override fun navigateToReportMessage(eventId: EventId, senderId: UserId) {

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/MessagesPresenter.kt

@@ -38,6 +38,8 @@ import io.element.android.features.messages.impl.messagecomposer.MessageComposer
 import io.element.android.features.messages.impl.messagecomposer.MessageComposerState
 import io.element.android.features.messages.impl.pinned.banner.PinnedMessagesBannerState
 import io.element.android.features.messages.impl.timeline.MarkAsFullyRead
+import io.element.android.features.messages.impl.timeline.SelectionAction
+import io.element.android.features.messages.impl.timeline.SelectionState
 import io.element.android.features.messages.impl.timeline.TimelineController
 import io.element.android.features.messages.impl.timeline.TimelineEvent
 import io.element.android.features.messages.impl.timeline.TimelineState
@@ -52,6 +54,7 @@ import io.element.android.features.messages.impl.timeline.model.event.TimelineIt
 import io.element.android.features.messages.impl.timeline.model.event.captionOrNull
 import io.element.android.features.messages.impl.timeline.model.event.htmlCaptionOrNull
 import io.element.android.features.messages.impl.timeline.protection.TimelineProtectionState
+import io.element.android.features.messages.impl.timeline.selectedEventIdsInTimelineOrder
 import io.element.android.features.messages.impl.voicemessages.composer.DefaultVoiceMessageComposerPresenter
 import io.element.android.features.roomcall.api.RoomCallState
 import io.element.android.features.roommembermoderation.api.RoomMemberModerationEvent
@@ -257,6 +260,17 @@ class MessagesPresenter(
                         redactEventAction = redactEventAction,
                     )
                 }
+                is MessagesEvent.ConfirmSelectionAction -> {
+                    val selection = timelineState.selectionState as? SelectionState.Active
+                    if (selection != null) {
+                        when (selection.action) {
+                            SelectionAction.Forward -> {
+                                navigator.forwardEvents(timelineState.selectedEventIdsInTimelineOrder(), timelineController)
+                            }
+                        }
+                        timelineState.eventSink(TimelineEvent.ExitSelectionMode)
+                    }
+                }
                 is MessagesEvent.ConfirmRedact -> {
                     val confirming = redactEventAction.value as? MessagesState.ConfirmingRedaction
                     redactEventAction.value = AsyncAction.Uninitialized
@@ -413,7 +427,14 @@ class MessagesPresenter(
                 }
             }
             TimelineItemAction.ViewSource -> handleShowDebugInfoAction(targetEvent)
-            TimelineItemAction.Forward -> handleForwardAction(targetEvent)
+            TimelineItemAction.Forward -> {
+                val eventId = targetEvent.eventId ?: return@launch
+                if (featureFlagService.isFeatureEnabled(FeatureFlags.MessageMultiSelect)) {
+                    timelineState.eventSink(TimelineEvent.EnterSelectionMode(SelectionAction.Forward, eventId))
+                } else {
+                    navigator.forwardEvents(listOf(eventId), timelineController)
+                }
+            }
             TimelineItemAction.ReportContent -> handleReportAction(targetEvent)
             TimelineItemAction.EndPoll -> handleEndPollAction(targetEvent, timelineState)
             TimelineItemAction.Pin -> handlePinAction(targetEvent)
@@ -612,11 +633,6 @@ class MessagesPresenter(
         navigator.navigateToEventDebugInfo(event.eventId, event.debugInfo)
     }
 
-    private fun handleForwardAction(event: TimelineItem.Event) {
-        if (event.eventId == null) return
-        navigator.forwardEvent(eventId = event.eventId, timelineProvider = timelineController)
-    }
-
     private fun handleReportAction(event: TimelineItem.Event) {
         if (event.eventId == null) return
         navigator.navigateToReportMessage(event.eventId, event.senderId)

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/MessagesView.kt

@@ -8,6 +8,7 @@
 
 package io.element.android.features.messages.impl
 
+import androidx.activity.compose.BackHandler
 import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.animation.expandVertically
 import androidx.compose.animation.shrinkVertically
@@ -77,24 +78,31 @@ import io.element.android.features.messages.impl.pinned.banner.PinnedMessagesBan
 import io.element.android.features.messages.impl.pinned.banner.PinnedMessagesBannerView
 import io.element.android.features.messages.impl.pinned.banner.PinnedMessagesBannerViewDefaults
 import io.element.android.features.messages.impl.timeline.FOCUS_ON_PINNED_EVENT_DEBOUNCE_DURATION_IN_MILLIS
+import io.element.android.features.messages.impl.timeline.SelectionAction
+import io.element.android.features.messages.impl.timeline.SelectionState
 import io.element.android.features.messages.impl.timeline.TimelineEvent
 import io.element.android.features.messages.impl.timeline.TimelineView
 import io.element.android.features.messages.impl.timeline.aGroupedEvents
 import io.element.android.features.messages.impl.timeline.aTimelineItemDaySeparator
 import io.element.android.features.messages.impl.timeline.aTimelineItemEvent
+import io.element.android.features.messages.impl.timeline.aTimelineItemList
 import io.element.android.features.messages.impl.timeline.aTimelineState
+import io.element.android.features.messages.impl.timeline.canApplyTo
 import io.element.android.features.messages.impl.timeline.components.CallMenuItem
 import io.element.android.features.messages.impl.timeline.components.customreaction.CustomReactionEvent
 import io.element.android.features.messages.impl.timeline.components.reactionsummary.ReactionSummaryEvent
 import io.element.android.features.messages.impl.timeline.components.reactionsummary.ReactionSummaryView
 import io.element.android.features.messages.impl.timeline.components.receipt.bottomsheet.ReadReceiptBottomSheet
 import io.element.android.features.messages.impl.timeline.components.receipt.bottomsheet.ReadReceiptBottomSheetEvent
+import io.element.android.features.messages.impl.timeline.isSelectionModeActive
 import io.element.android.features.messages.impl.timeline.model.TimelineItem
 import io.element.android.features.messages.impl.timeline.model.TimelineItemGroupPosition
 import io.element.android.features.messages.impl.timeline.model.event.aTimelineItemStateEventContent
 import io.element.android.features.messages.impl.timeline.model.event.aTimelineItemTextContent
+import io.element.android.features.messages.impl.timeline.selectedCount
 import io.element.android.features.messages.impl.timeline.sendfailure.SendFailureDialogView
 import io.element.android.features.messages.impl.topbars.MessagesViewTopBar
+import io.element.android.features.messages.impl.topbars.SelectionModeTopBar
 import io.element.android.features.messages.impl.topbars.ThreadTopBar
 import io.element.android.features.messages.impl.voicemessages.composer.VoiceMessagePermissionRationaleDialog
 import io.element.android.features.messages.impl.voicemessages.composer.VoiceMessageSendingFailedDialog
@@ -134,6 +142,7 @@ import io.element.android.libraries.textcomposer.model.TextEditorState
 import io.element.android.libraries.ui.strings.CommonStrings
 import io.element.android.wysiwyg.link.Link
 import kotlinx.collections.immutable.persistentListOf
+import kotlinx.collections.immutable.toImmutableSet
 import timber.log.Timber
 import kotlin.time.Duration.Companion.milliseconds
 
@@ -178,6 +187,18 @@ fun MessagesView(
         block()
     }
 
+    // Entering selection mode collapses the composer, so dismiss the keyboard too. hideKeyboard
+    // triggers the IME hide animation, keeping it in sync with the composer collapse.
+    LaunchedEffect(state.timelineState.isSelectionModeActive) {
+        if (state.timelineState.isSelectionModeActive) {
+            localView.hideKeyboard()
+        }
+    }
+
+    BackHandler(enabled = state.timelineState.isSelectionModeActive) {
+        state.timelineState.eventSink(TimelineEvent.ExitSelectionMode)
+    }
+
     fun onContentClick(event: TimelineItem.Event) {
         Timber.v("onMessageClick= ${event.id}")
         val eventId = event.eventId
@@ -234,34 +255,50 @@ fun MessagesView(
             Scaffold(
                 contentWindowInsets = scaffoldScrollableContentInsets,
                 topBar = {
-                    if (state.timelineState.timelineMode is Timeline.Mode.Thread) {
-                        ThreadTopBar(
-                            roomName = state.roomName,
-                            roomAvatarData = state.roomAvatar,
-                            heroes = state.heroes,
-                            isTombstoned = state.isTombstoned,
-                            onBackClick = onBackClick,
-                        )
-                    } else {
-                        MessagesViewTopBar(
-                            roomName = state.roomName,
-                            roomAvatar = state.roomAvatar,
-                            isTombstoned = state.isTombstoned,
-                            heroes = state.heroes,
-                            dmUserIdentityState = state.dmUserVerificationState,
-                            sharedHistoryIcon = state.topBarSharedHistoryIcon,
-                            dmUserStatus = state.dmUserStatus,
-                            onBackClick = { hidingKeyboard { onBackClick() } },
-                            onRoomDetailsClick = { hidingKeyboard { onRoomDetailsClick() } },
-                            menuActions = {
-                                MessagesMenuActions(
-                                    displayThreads = state.timelineState.timelineMode !is Timeline.Mode.Thread && state.threads.hasThreads,
-                                    roomCallState = state.roomCallState,
-                                    onJoinCallClick = onJoinCallClick,
-                                    onThreadsListClick = onThreadsListClick
-                                )
-                            }
-                        )
+                    when {
+                        state.timelineState.isSelectionModeActive -> {
+                            val selection = state.timelineState.selectionState as SelectionState.Active
+                            SelectionModeTopBar(
+                                selectedCount = state.timelineState.selectedCount,
+                                action = selection.action,
+                                onCancelClick = {
+                                    state.timelineState.eventSink(TimelineEvent.ExitSelectionMode)
+                                },
+                                onConfirmClick = {
+                                    state.eventSink(MessagesEvent.ConfirmSelectionAction)
+                                },
+                            )
+                        }
+                        state.timelineState.timelineMode is Timeline.Mode.Thread -> {
+                            ThreadTopBar(
+                                roomName = state.roomName,
+                                roomAvatarData = state.roomAvatar,
+                                heroes = state.heroes,
+                                isTombstoned = state.isTombstoned,
+                                onBackClick = onBackClick,
+                            )
+                        }
+                        else -> {
+                            MessagesViewTopBar(
+                                roomName = state.roomName,
+                                roomAvatar = state.roomAvatar,
+                                isTombstoned = state.isTombstoned,
+                                heroes = state.heroes,
+                                dmUserIdentityState = state.dmUserVerificationState,
+                                sharedHistoryIcon = state.topBarSharedHistoryIcon,
+                                dmUserStatus = state.dmUserStatus,
+                                onBackClick = { hidingKeyboard { onBackClick() } },
+                                onRoomDetailsClick = { hidingKeyboard { onRoomDetailsClick() } },
+                                menuActions = {
+                                    MessagesMenuActions(
+                                        displayThreads = state.timelineState.timelineMode !is Timeline.Mode.Thread && state.threads.hasThreads,
+                                        roomCallState = state.roomCallState,
+                                        onJoinCallClick = onJoinCallClick,
+                                        onThreadsListClick = onThreadsListClick
+                                    )
+                                }
+                            )
+                        }
                     }
                 },
                 content = { padding ->
@@ -728,6 +765,40 @@ internal fun MessagesViewPreview(@PreviewParameter(MessagesStatePreviewParam::cl
     )
 }
 
+@PreviewsDayNight
+@Composable
+internal fun MessagesViewSelectionModePreview() = ElementPreview {
+    val timelineItems = aTimelineItemList(aTimelineItemTextContent())
+    val selectedEventIds = timelineItems
+        .filterIsInstance<TimelineItem.Event>()
+        .filter { SelectionAction.Forward.canApplyTo(it) }
+        .take(2)
+        .mapNotNull { it.eventId }
+        .toImmutableSet()
+    MessagesView(
+        state = aMessagesState(
+            timelineState = aTimelineState(
+                timelineItems = timelineItems,
+                selectionState = SelectionState.Active(SelectionAction.Forward, selectedEventIds),
+            ),
+        ),
+        onBackClick = {},
+        onRoomDetailsClick = {},
+        onEventContentClick = { _, _ -> false },
+        onGalleryEventItemClick = { _, _, _ -> false },
+        onUserDataClick = {},
+        onLinkClick = { _, _ -> },
+        onSendLocationClick = {},
+        onCreatePollClick = {},
+        onJoinCallClick = {},
+        onViewAllPinnedMessagesClick = { },
+        forceJumpToBottomVisibility = true,
+        knockRequestsBannerView = {},
+        customReactionBottomSheet = {},
+        onThreadsListClick = {},
+    )
+}
+
 @Preview
 @Composable
 internal fun MessagesViewA11yPreview() = ElementPreview {

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/pinned/list/PinnedMessagesListView.kt

@@ -38,6 +38,7 @@ import io.element.android.features.messages.impl.timeline.components.event.Timel
 import io.element.android.features.messages.impl.timeline.components.reactionsummary.ReactionSummaryEvent
 import io.element.android.features.messages.impl.timeline.components.reactionsummary.ReactionSummaryView
 import io.element.android.features.messages.impl.timeline.model.TimelineItem
+import io.element.android.features.messages.impl.timeline.model.TimelineItemSelectionData
 import io.element.android.features.messages.impl.timeline.model.event.TimelineItemPollContent
 import io.element.android.features.messages.impl.timeline.protection.TimelineProtectionState
 import io.element.android.features.poll.api.pollcontent.PollTitleView
@@ -289,6 +290,7 @@ private fun PinnedMessagesListLoaded(
                         onContentLayoutChange = onContentLayoutChange
                     )
                 },
+                selectionData = TimelineItemSelectionData(),
             )
         }
     }

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/threads/ThreadedMessagesNode.kt

@@ -143,7 +143,7 @@ class ThreadedMessagesNode(
         fun navigateToRoomMemberDetails(userId: UserId)
         fun handlePermalinkClick(data: PermalinkData)
         fun navigateToEventDebugInfo(eventId: EventId?, debugInfo: TimelineItemDebugInfo)
-        fun handleForwardEventClick(eventId: EventId, timelineProvider: TimelineProvider)
+        fun handleForwardEventClick(eventIds: List<EventId>, timelineProvider: TimelineProvider)
         fun navigateToReportMessage(eventId: EventId, senderId: UserId)
         fun navigateToSendLocation()
         fun navigateToCreatePoll()
@@ -227,8 +227,8 @@ class ThreadedMessagesNode(
         callback.navigateToEventDebugInfo(eventId, debugInfo)
     }
 
-    override fun forwardEvent(eventId: EventId, timelineProvider: TimelineProvider) {
-        callback.handleForwardEventClick(eventId, timelineProvider)
+    override fun forwardEvents(eventIds: List<EventId>, timelineProvider: TimelineProvider) {
+        callback.handleForwardEventClick(eventIds, timelineProvider)
     }
 
     override fun navigateToReportMessage(eventId: EventId, senderId: UserId) {

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/SelectionState.kt

@@ -0,0 +1,88 @@
+/*
+ * Copyright (c) 2026 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.messages.impl.timeline
+
+import androidx.annotation.DrawableRes
+import androidx.annotation.StringRes
+import androidx.compose.runtime.Immutable
+import io.element.android.compound.R
+import io.element.android.features.messages.impl.timeline.model.TimelineItem
+import io.element.android.features.messages.impl.timeline.model.event.canBeForwarded
+import io.element.android.libraries.matrix.api.core.EventId
+import io.element.android.libraries.ui.strings.CommonStrings
+import kotlinx.collections.immutable.ImmutableSet
+import kotlinx.collections.immutable.toImmutableSet
+
+/** Maximum number of messages that can be selected at once. */
+const val MAX_SELECTION_COUNT = 10
+
+@Immutable
+sealed interface SelectionState {
+    /** Selection mode is not active. */
+    data object Disabled : SelectionState
+
+    /**
+     * Selection mode is active for [action], with the given selection.
+     * [selectedEventIds] can be empty: selection mode is never exited automatically, only when the user explicitly leaves it.
+     */
+    data class Active(
+        val action: SelectionAction,
+        val selectedEventIds: ImmutableSet<EventId>,
+    ) : SelectionState
+}
+
+/**
+ * An action which can be performed on several timeline events at once, and which selection mode can be entered for.
+ */
+enum class SelectionAction(@field:StringRes val titleRes: Int, @field:DrawableRes val iconRes: Int) {
+    Forward(CommonStrings.action_forward, R.drawable.ic_compound_forward),
+}
+
+/**
+ * Whether [event] can be part of a selection made for this action.
+ * Each action uses the same criteria as the single event action it mirrors.
+ */
+fun SelectionAction.canApplyTo(event: TimelineItem.Event): Boolean = when (this) {
+    SelectionAction.Forward -> event.isRemote && event.content.canBeForwarded()
+}
+
+/**
+ * This selection without [eventIds].
+ * Selection mode stays active even when nothing remains selected, see [SelectionState.Active].
+ */
+fun SelectionState.deselect(eventIds: Set<EventId>): SelectionState = when (this) {
+    SelectionState.Disabled -> this
+    is SelectionState.Active -> copy(selectedEventIds = (selectedEventIds - eventIds).toImmutableSet())
+}
+
+/**
+ * The ids of the selected events which [SelectionState.Active.action] cannot be applied to anymore, for instance because the message has been
+ * deleted. They are meant to be given to [deselect].
+ */
+fun SelectionState.eventIdsToDeselect(timelineItems: List<TimelineItem>): Set<EventId> {
+    val selection = this as? SelectionState.Active ?: return emptySet()
+    if (selection.selectedEventIds.isEmpty()) return emptySet()
+    val result = mutableSetOf<EventId>()
+
+    fun process(event: TimelineItem.Event) {
+        val eventId = event.eventId ?: return
+        if (eventId in selection.selectedEventIds && !selection.action.canApplyTo(event)) {
+            result.add(eventId)
+        }
+    }
+
+    timelineItems.forEach { item ->
+        when (item) {
+            is TimelineItem.Event -> process(item)
+            // A deleted message can be folded into a group of deleted messages, so look inside the groups too.
+            is TimelineItem.GroupedEvents -> item.events.forEach(::process)
+            is TimelineItem.Virtual -> Unit
+        }
+    }
+    return result
+}

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/TimelineEvent.kt

@@ -28,7 +28,9 @@ sealed interface TimelineEvent {
     data object HideShieldDialog : TimelineEvent
 
     data object MarkAllAsRead : TimelineEvent
-
+    data class EnterSelectionMode(val action: SelectionAction, val eventId: EventId) : TimelineEvent
+    data class ToggleSelection(val eventId: EventId) : TimelineEvent
+    data object ExitSelectionMode : TimelineEvent
     data class CopyToClipboard(val text: String) : TimelineEvent
 
     /**

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/TimelinePresenter.kt

@@ -48,6 +48,8 @@ import io.element.android.libraries.androidutils.clipboard.ClipboardHelper
 import io.element.android.libraries.androidutils.toast.ToastHelper
 import io.element.android.libraries.architecture.Presenter
 import io.element.android.libraries.core.coroutine.CoroutineDispatchers
+import io.element.android.libraries.designsystem.utils.snackbar.SnackbarDispatcher
+import io.element.android.libraries.designsystem.utils.snackbar.SnackbarMessage
 import io.element.android.libraries.di.annotations.SessionCoroutineScope
 import io.element.android.libraries.featureflag.api.FeatureFlagService
 import io.element.android.libraries.featureflag.api.FeatureFlags
@@ -71,13 +73,17 @@ import io.element.android.services.analytics.api.finishLongRunningTransaction
 import io.element.android.services.analyticsproviders.api.AnalyticsUserData
 import kotlinx.collections.immutable.ImmutableList
 import kotlinx.collections.immutable.persistentListOf
+import kotlinx.collections.immutable.persistentSetOf
 import kotlinx.collections.immutable.toImmutableList
+import kotlinx.collections.immutable.toImmutableSet
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.filter
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.flow.flowOn
 import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
@@ -103,6 +109,7 @@ class TimelinePresenter(
     private val typingNotificationPresenter: Presenter<TypingNotificationState>,
     private val roomCallStatePresenter: Presenter<RoomCallState>,
     private val featureFlagService: FeatureFlagService,
+    private val snackbarDispatcher: SnackbarDispatcher,
     private val analyticsService: AnalyticsService,
     private val liveLocationShareManager: ActiveLiveLocationShareManager,
     private val markAsFullyRead: MarkAsFullyRead,
@@ -172,6 +179,18 @@ class TimelinePresenter(
             value = featureFlagService.isFeatureEnabled(FeatureFlags.NewTimelineEventRenderer)
         }
 
+        val isMultiSelectEnabled by produceState(false) {
+            featureFlagService.isFeatureEnabledFlow(FeatureFlags.MessageMultiSelect).collect { value = it }
+        }
+        var selectionState by remember { mutableStateOf<SelectionState>(SelectionState.Disabled) }
+
+        // When the feature flag is turned off, clear any active selection.
+        LaunchedEffect(isMultiSelectEnabled) {
+            if (!isMultiSelectEnabled) {
+                selectionState = SelectionState.Disabled
+            }
+        }
+
         val timelineProtectionState = timelineProtectionPresenter.present()
 
         fun handleEvent(event: TimelineEvent) {
@@ -252,6 +271,26 @@ class TimelinePresenter(
                 is TimelineEvent.JumpToLive -> {
                     timelineController.focusOnLive()
                 }
+                is TimelineEvent.EnterSelectionMode -> {
+                    if (!isMultiSelectEnabled) return
+                    selectionState = SelectionState.Active(event.action, persistentSetOf(event.eventId))
+                }
+                is TimelineEvent.ToggleSelection -> {
+                    val current = selectionState as? SelectionState.Active ?: return
+                    val selected = current.selectedEventIds
+                    selectionState = when {
+                        // Deselecting the last event does not exit selection mode: it is only left explicitly, as on iOS.
+                        event.eventId in selected -> current.deselect(setOf(event.eventId))
+                        selected.size >= MAX_SELECTION_COUNT -> {
+                            snackbarDispatcher.post(SnackbarMessage(CommonStrings.screen_room_maximum_messages_selected))
+                            current
+                        }
+                        else -> current.copy(selectedEventIds = (selected + event.eventId).toImmutableSet())
+                    }
+                }
+                is TimelineEvent.ExitSelectionMode -> {
+                    selectionState = SelectionState.Disabled
+                }
                 TimelineEvent.HideShieldDialog -> messageShieldDialogData.value = null
                 TimelineEvent.MarkAllAsRead -> sessionCoroutineScope.launch {
                     val latestEventId = room.liveTimeline.getLatestEventId().getOrElse {
@@ -341,6 +380,14 @@ class TimelinePresenter(
                 }
                 .launchIn(this)
 
+            // Drop the selected events which the action cannot be applied to anymore, for instance because the message has been deleted.
+            timelineItemsFactory.timelineItems
+                .map { items -> selectionState.eventIdsToDeselect(items) }
+                .filter { eventIdsToDeselect -> eventIdsToDeselect.isNotEmpty() }
+                .flowOn(dispatchers.computation)
+                .onEach { eventIdsToDeselect -> selectionState = selectionState.deselect(eventIdsToDeselect) }
+                .launchIn(this)
+
             combine(
                 timelineController.timelineItems(),
                 room.membersStateFlow,
@@ -477,6 +524,7 @@ class TimelinePresenter(
             displayThreadSummaries = displayThreadSummaries,
             displayJumpToUnread = displayJumpToUnread,
             jumpToUnread = jumpToUnread.value,
+            selectionState = selectionState,
             useNewTimelineEventRenderer = useNewTimelineEventRenderer,
             eventSink = ::handleEvent,
         )

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/TimelineState.kt

@@ -22,6 +22,8 @@ import io.element.android.libraries.matrix.api.core.UserId
 import io.element.android.libraries.matrix.api.room.tombstone.PredecessorRoom
 import io.element.android.libraries.matrix.api.timeline.Timeline
 import kotlinx.collections.immutable.ImmutableList
+import kotlinx.collections.immutable.persistentListOf
+import kotlinx.collections.immutable.toImmutableList
 import kotlin.time.Duration
 
 data class TimelineState(
@@ -38,6 +40,7 @@ data class TimelineState(
     val displayThreadSummaries: Boolean,
     val displayJumpToUnread: Boolean,
     val jumpToUnread: JumpToUnreadState,
+    val selectionState: SelectionState,
     // When true, formatted message bodies are rendered with the native Compose renderer.
     val useNewTimelineEventRenderer: Boolean,
     val eventSink: (TimelineEvent) -> Unit,
@@ -104,3 +107,43 @@ sealed interface JumpToUnreadState {
     /** The read marker event is older than the loaded window — load it via focused-event navigation. */
     data class OutOfWindow(val eventId: EventId) : JumpToUnreadState
 }
+
+val TimelineState.isSelectionModeActive: Boolean
+    get() = selectionState is SelectionState.Active
+
+val TimelineState.selectedCount: Int
+    get() = (selectionState as? SelectionState.Active)?.selectedEventIds?.size ?: 0
+
+fun TimelineState.isSelected(item: TimelineItem): Boolean {
+    val selection = selectionState as? SelectionState.Active ?: return false
+    return when (item) {
+        is TimelineItem.Event -> selection.selectedEventIds.contains(item.eventId)
+        else -> false
+    }
+}
+
+/**
+ * Whether [item] can be selected right now: selection mode must be active, and the action it was entered for must accept this event.
+ */
+fun TimelineState.canSelect(item: TimelineItem): Boolean {
+    val selection = selectionState as? SelectionState.Active ?: return false
+    return when (item) {
+        is TimelineItem.Event -> selection.action.canApplyTo(item)
+        else -> false
+    }
+}
+
+/**
+ * The selected event ids, sorted from the oldest to the most recent one, as they appear in the timeline.
+ * The selection itself is stored as a set, in the order the events were tapped, which is not necessarily the order they must be acted on.
+ */
+fun TimelineState.selectedEventIdsInTimelineOrder(): ImmutableList<EventId> {
+    val selectedEventIds = (selectionState as? SelectionState.Active)?.selectedEventIds ?: return persistentListOf()
+    return timelineItems
+        .filterIsInstance<TimelineItem.Event>()
+        .mapNotNull { it.eventId }
+        .filter { it in selectedEventIds }
+        // Most recent item is first in the timeline, so reverse the result.
+        .reversed()
+        .toImmutableList()
+}

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/TimelineStateProvider.kt

@@ -63,6 +63,7 @@ fun aTimelineState(
     displayJumpToUnread: Boolean = false,
     jumpToUnread: JumpToUnreadState = JumpToUnreadState.Hidden,
     newEventState: NewEventState = NewEventState.None,
+    selectionState: SelectionState = SelectionState.Disabled,
     useNewTimelineEventRenderer: Boolean = false,
     eventSink: (TimelineEvent) -> Unit = {},
 ): TimelineState {
@@ -85,6 +86,7 @@ fun aTimelineState(
         displayThreadSummaries = displayThreadSummaries,
         displayJumpToUnread = displayJumpToUnread,
         jumpToUnread = jumpToUnread,
+        selectionState = selectionState,
         useNewTimelineEventRenderer = useNewTimelineEventRenderer,
         eventSink = eventSink,
     )

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/TimelineView.kt

@@ -11,6 +11,7 @@ package io.element.android.features.messages.impl.timeline
 import android.view.HapticFeedbackConstants
 import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.animation.core.MutableTransitionState
+import androidx.compose.animation.core.animateFloatAsState
 import androidx.compose.animation.core.tween
 import androidx.compose.animation.fadeIn
 import androidx.compose.animation.fadeOut
@@ -88,8 +89,10 @@ import io.element.android.features.messages.impl.timeline.di.aFakeTimelineItemPr
 import io.element.android.features.messages.impl.timeline.focus.FocusRequestStateView
 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.TimelineItemSelectionData
 import io.element.android.features.messages.impl.timeline.model.event.TimelineItemEventContent
 import io.element.android.features.messages.impl.timeline.model.event.TimelineItemEventContentPreviewParam
+import io.element.android.features.messages.impl.timeline.model.event.aTimelineItemTextContent
 import io.element.android.features.messages.impl.timeline.protection.TimelineProtectionState
 import io.element.android.features.messages.impl.timeline.protection.aTimelineProtectionState
 import io.element.android.libraries.designsystem.atomic.atoms.UnreadIndicatorAtom
@@ -108,6 +111,7 @@ import io.element.android.libraries.testtags.testTag
 import io.element.android.libraries.ui.strings.CommonStrings
 import io.element.android.wysiwyg.link.Link
 import kotlinx.collections.immutable.persistentListOf
+import kotlinx.collections.immutable.persistentSetOf
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.flow.combine
@@ -181,6 +185,18 @@ fun TimelineView(
         state.eventSink(TimelineEvent.LoadMore(Timeline.PaginationDirection.BACKWARDS))
     }
 
+    val isSelectionModeActive = state.isSelectionModeActive
+    // Animate once here (shared by every row) rather than per-row: the value is identical for all
+    // rows since it only depends on the timeline-wide selection mode.
+    val selectionProgress by animateFloatAsState(
+        targetValue = if (isSelectionModeActive) 1f else 0f,
+        label = "selectionProgress",
+    )
+    fun onToggleSelection(event: TimelineItem.Event) {
+        val eventId = event.eventId ?: return
+        state.eventSink(TimelineEvent.ToggleSelection(eventId))
+    }
+
     // Animate alpha when timeline is first displayed, to avoid flashes or glitching when viewing rooms
     AnimatedVisibility(visible = true, enter = fadeIn()) {
         val composeLocalTimelineEventRendererConfig = remember(state.useNewTimelineEventRenderer, state.timelineRoomInfo.currentUserId) {
@@ -213,12 +229,22 @@ fun TimelineView(
                             isLastOutgoingMessage = state.isLastOutgoingMessage(timelineItem.identifier()),
                             focusedEventId = state.focusedEventId,
                             displayThreadSummaries = state.displayThreadSummaries,
+                            selectionData = TimelineItemSelectionData(
+                                isSelectionModeActive = isSelectionModeActive,
+                                progress = selectionProgress,
+                                isSelected = state.isSelected(timelineItem),
+                                canBeSelected = state.canSelect(timelineItem),
+                            ),
                             onUserDataClick = onUserDataClick,
                             onLinkClick = onLinkClick,
                             onLinkLongClick = ::onLinkLongClick,
-                            onContentClick = onContentClick,
+                            onContentClick = { event ->
+                                if (state.canSelect(event)) onToggleSelection(event) else onContentClick(event)
+                            },
                             onGalleryItemClick = onGalleryItemClick,
-                            onLongClick = onMessageLongClick,
+                            onLongClick = { event ->
+                                if (state.canSelect(event)) onToggleSelection(event) else onMessageLongClick(event)
+                            },
                             inReplyToClick = ::inReplyToClick,
                             onReactionClick = onReactionClick,
                             onReactionLongClick = onReactionLongClick,
@@ -617,6 +643,36 @@ internal fun TimelineViewPreview(
     }
 }
 
+@PreviewsDayNight
+@Composable
+internal fun TimelineViewSelectionModePreview() = ElementPreview {
+    val timelineItems = aTimelineItemList(aTimelineItemTextContent())
+    val selectedEventId = timelineItems.filterIsInstance<TimelineItem.Event>().first { SelectionAction.Forward.canApplyTo(it) }.eventId!!
+    CompositionLocalProvider(
+        LocalTimelineItemPresenterFactories provides aFakeTimelineItemPresenterFactories(),
+    ) {
+        TimelineView(
+            state = aTimelineState(
+                timelineItems = timelineItems,
+                selectionState = SelectionState.Active(SelectionAction.Forward, persistentSetOf(selectedEventId)),
+            ),
+            timelineProtectionState = aTimelineProtectionState(),
+            onUserDataClick = {},
+            onLinkClick = {},
+            onContentClick = {},
+            onMessageLongClick = {},
+            onSwipeToReply = {},
+            onReactionClick = { _, _ -> },
+            onReactionLongClick = { _, _ -> },
+            onJoinCallClick = {},
+            onMoreReactionsClick = {},
+            onReadReceiptClick = {},
+            onGalleryItemClick = { _, _ -> },
+            forceJumpToBottomVisibility = true,
+        )
+    }
+}
+
 // The jump-to-unread FAB's indicator is always rendered when the FAB is visible — in
 // production the FAB only appears when unread content exists above. So `hasUnreadAbove`
 // here only varies the scroll-target state, not the upper indicator's visibility.

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/components/MessageEventBubble.kt

@@ -32,6 +32,8 @@ import androidx.compose.ui.graphics.Shape
 import androidx.compose.ui.graphics.drawOutline
 import androidx.compose.ui.graphics.drawscope.Stroke
 import androidx.compose.ui.graphics.layer.CompositingStrategy
+import androidx.compose.ui.layout.HorizontalAlignmentLine
+import androidx.compose.ui.layout.layout
 import androidx.compose.ui.tooling.preview.PreviewParameter
 import androidx.compose.ui.unit.LayoutDirection
 import androidx.compose.ui.unit.dp
@@ -53,12 +55,20 @@ import io.element.android.libraries.testtags.TestTags
 import io.element.android.libraries.testtags.testTag
 import io.element.android.libraries.ui.utils.a11y.isTalkbackActive
 import io.element.android.libraries.ui.utils.graphics.drawInLayer
+import kotlin.math.min
 
 private val BUBBLE_RADIUS = 12.dp
 private val avatarRadius = AvatarSize.TimelineSender.dp / 2
 
 private val MIN_BUBBLE_WIDTH = 80.dp
 
+/**
+ * Alignment line published by [MessageEventBubble] at its vertical center.
+ * It lets the timeline row align decorations with the bubble itself, instead of with the whole row, whose height also
+ * covers the sender information, the reactions, the thread summary and the read receipts.
+ */
+val BubbleVerticalCenter = HorizontalAlignmentLine(::min)
+
 @Composable
 fun MessageEventBubble(
     state: BubbleState,
@@ -93,6 +103,12 @@ fun MessageEventBubble(
     val updatedBorderColor by rememberUpdatedState(borderColor)
     BoxWithConstraints(
         modifier = modifier
+            .layout { measurable, constraints ->
+                val placeable = measurable.measure(constraints)
+                layout(placeable.width, placeable.height, mapOf(BubbleVerticalCenter to placeable.height / 2)) {
+                    placeable.place(0, 0)
+                }
+            }
             .drawWithCache {
                 // Calculate the outline of the background and cache it
                 val outline = bubbleShape.createOutline(size, layoutDirection, this)

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/components/SelectionIndicator.kt

@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2026 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.messages.impl.timeline.components
+
+import androidx.compose.material3.LocalMinimumInteractiveComponentSize
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.Dp
+import io.element.android.libraries.designsystem.preview.ElementPreview
+import io.element.android.libraries.designsystem.preview.PreviewsDayNight
+import io.element.android.libraries.designsystem.theme.components.Checkbox
+
+/**
+ * Selection indicator used in the timeline selection mode. It renders the Compound [Checkbox], with the minimum
+ * interactive size enforcement disabled so that it fits the compact selection column. It is purely visual: the tap
+ * is handled by the whole-row click target, so this only reflects [selected].
+ */
+@Composable
+internal fun SelectionIndicator(
+    selected: Boolean,
+    modifier: Modifier = Modifier,
+) {
+    CompositionLocalProvider(LocalMinimumInteractiveComponentSize provides Dp.Unspecified) {
+        Checkbox(
+            modifier = modifier,
+            checked = selected,
+            onCheckedChange = null,
+        )
+    }
+}
+
+@PreviewsDayNight
+@Composable
+internal fun SelectionIndicatorPreview() = ElementPreview {
+    SelectionIndicator(selected = false)
+}
+
+@PreviewsDayNight
+@Composable
+internal fun SelectionIndicatorSelectedPreview() = ElementPreview {
+    SelectionIndicator(selected = true)
+}

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/components/TimelineItemEventRow.kt

@@ -24,6 +24,7 @@ import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.absoluteOffset
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.offset
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.width
@@ -59,6 +60,7 @@ import androidx.compose.ui.semantics.traversalIndex
 import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.text.style.TextDirection
 import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.Dp
 import androidx.compose.ui.unit.DpOffset
 import androidx.compose.ui.unit.IntOffset
 import androidx.compose.ui.unit.LayoutDirection
@@ -180,6 +182,9 @@ fun TimelineItemEventRow(
     onSwipeToReply: () -> Unit,
     eventSink: (TimelineEvent.TimelineItemEvent) -> Unit,
     modifier: Modifier = Modifier,
+    // Horizontal offset applied to this row's content by selection mode. The read receipts are
+    // anchored to the end edge and should stay pinned, so they are counter-offset by this amount.
+    selectionContentOffset: Dp = 0.dp,
     eventContentView: @Composable (Modifier, (ContentAvoidingLayoutData) -> Unit) -> Unit = { contentModifier, onContentLayoutChange ->
         // Only pass down a custom clickable lambda if the content can be clicked separately
         val onContentClick = onEventClick.takeUnless { event.isWholeContentClickable }
@@ -326,7 +331,10 @@ fun TimelineItemEventRow(
                 receipts = event.readReceiptState.receipts,
             ),
             onReadReceiptsClick = { onReadReceiptClick(event) },
-            modifier = Modifier.padding(top = 4.dp)
+            // Counter the selection-mode content slide so the end-anchored read receipts stay pinned.
+            modifier = Modifier
+                .padding(top = 4.dp)
+                .offset(x = -selectionContentOffset)
         )
     }
 }

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/components/TimelineItemGroupedEventsRow.kt

@@ -27,6 +27,7 @@ import io.element.android.features.messages.impl.timeline.components.receipt.Rea
 import io.element.android.features.messages.impl.timeline.components.receipt.TimelineItemReadReceiptView
 import io.element.android.features.messages.impl.timeline.groups.isRedactedMessagesGroup
 import io.element.android.features.messages.impl.timeline.model.TimelineItem
+import io.element.android.features.messages.impl.timeline.model.TimelineItemSelectionData
 import io.element.android.features.messages.impl.timeline.protection.TimelineProtectionState
 import io.element.android.features.messages.impl.timeline.protection.aTimelineProtectionState
 import io.element.android.libraries.designsystem.preview.ElementPreview
@@ -190,6 +191,7 @@ private fun TimelineItemGroupedEventsRowContent(
                         onSwipeToReply = {},
                         eventSink = eventSink,
                         eventContentView = eventContentView,
+                        selectionData = TimelineItemSelectionData(),
                     )
                 }
             }

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/components/TimelineItemRow.kt

@@ -8,28 +8,39 @@
 
 package io.element.android.features.messages.impl.timeline.components
 
+import androidx.compose.foundation.clickable
 import androidx.compose.foundation.combinedClickable
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.offset
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.drawWithCache
 import androidx.compose.ui.geometry.Offset
 import androidx.compose.ui.geometry.Size
 import androidx.compose.ui.graphics.Brush
+import androidx.compose.ui.graphics.graphicsLayer
+import androidx.compose.ui.layout.AlignmentLine
+import androidx.compose.ui.layout.Layout
+import androidx.compose.ui.platform.LocalLayoutDirection
 import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.semantics.Role
 import androidx.compose.ui.semantics.contentDescription
 import androidx.compose.ui.semantics.isTraversalGroup
 import androidx.compose.ui.semantics.semantics
+import androidx.compose.ui.unit.Constraints
 import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.LayoutDirection
 import androidx.compose.ui.unit.dp
 import io.element.android.compound.theme.ElementTheme
 import io.element.android.features.messages.impl.timeline.TimelineEvent
 import io.element.android.features.messages.impl.timeline.TimelineRoomInfo
 import io.element.android.features.messages.impl.timeline.components.event.TimelineItemEventContentView
 import io.element.android.features.messages.impl.timeline.model.TimelineItem
+import io.element.android.features.messages.impl.timeline.model.TimelineItemSelectionData
 import io.element.android.features.messages.impl.timeline.model.event.RtcNotificationState
 import io.element.android.features.messages.impl.timeline.model.event.TimelineItemLegacyCallInviteContent
 import io.element.android.features.messages.impl.timeline.model.event.TimelineItemPollContent
@@ -60,6 +71,7 @@ internal fun TimelineItemRow(
     timelineProtectionState: TimelineProtectionState,
     focusedEventId: EventId?,
     displayThreadSummaries: Boolean,
+    selectionData: TimelineItemSelectionData,
     onUserDataClick: (MatrixUser) -> Unit,
     onLinkClick: (Link) -> Unit,
     onLinkLongClick: (Link) -> Unit,
@@ -92,17 +104,148 @@ internal fun TimelineItemRow(
             )
         },
 ) {
-    val backgroundModifier = if (timelineItem.isEvent(focusedEventId)) {
-        val focusedEventOffset = if ((timelineItem as? TimelineItem.Event)?.showSenderInformation == true) {
-            14.dp
-        } else {
-            2.dp
+    val isSelectionModeActive = selectionData.isSelectionModeActive
+    val selectionProgress = selectionData.progress
+    val isSelected = selectionData.isSelected
+    val backgroundModifier = when {
+        timelineItem.isEvent(focusedEventId) && !isSelectionModeActive -> {
+            val focusedEventOffset =
+                if ((timelineItem as? TimelineItem.Event)?.showSenderInformation == true) {
+                    14.dp
+                } else {
+                    2.dp
+                }
+            Modifier.focusedEvent(focusedEventOffset)
+        }
+        else -> {
+            Modifier
         }
-        Modifier.focusedEvent(focusedEventOffset)
-    } else {
-        Modifier
     }
-    Box(modifier = modifier.then(backgroundModifier)) {
+    val selectableEvent = (timelineItem as? TimelineItem.Event)?.takeIf { selectionData.canBeSelected }
+    // Only start-aligned message bubbles slide to make room for the selection indicator:
+    //  - Outgoing (own) messages are end-aligned, opposite the indicator, so they already have room.
+    //  - Centered tiles (state events, call tiles, day dividers, grouped events) must stay put.
+    val isOutgoing = (timelineItem as? TimelineItem.Event)?.isMine == true
+    val shouldSlideContent = timelineItem.rendersAsBubble() && !isOutgoing
+    val layoutDirection = LocalLayoutDirection.current
+    val contentSlide = if (shouldSlideContent) SELECTION_COLUMN_WIDTH * selectionProgress else 0.dp
+    Layout(
+        modifier = modifier.then(backgroundModifier),
+        contents = listOf(
+            {
+                TimelineItemRowContent(
+                    modifier = Modifier
+                        .fillMaxWidth()
+                        .offset(x = contentSlide),
+                    selectionContentOffset = contentSlide,
+                    timelineItem = timelineItem,
+                    timelineMode = timelineMode,
+                    timelineRoomInfo = timelineRoomInfo,
+                    timelineProtectionState = timelineProtectionState,
+                    isLastOutgoingMessage = isLastOutgoingMessage,
+                    focusedEventId = focusedEventId,
+                    displayThreadSummaries = displayThreadSummaries,
+                    onUserDataClick = onUserDataClick,
+                    onLinkClick = onLinkClick,
+                    onLinkLongClick = onLinkLongClick,
+                    onContentClick = onContentClick,
+                    onGalleryItemClick = onGalleryItemClick,
+                    onLongClick = onLongClick,
+                    inReplyToClick = inReplyToClick,
+                    onReactionClick = onReactionClick,
+                    onReactionLongClick = onReactionLongClick,
+                    onMoreReactionsClick = onMoreReactionsClick,
+                    onReadReceiptClick = onReadReceiptClick,
+                    onJoinCallClick = onJoinCallClick,
+                    onSwipeToReply = onSwipeToReply,
+                    eventSink = eventSink,
+                    eventContentView = eventContentView,
+                )
+            },
+            {
+                if (selectableEvent != null && selectionProgress > 0f) {
+                    val slideSign = if (layoutDirection == LayoutDirection.Ltr) -1f else 1f
+                    SelectionIndicator(
+                        selected = isSelected,
+                        modifier = Modifier
+                            .graphicsLayer { translationX = slideSign * SELECTION_COLUMN_WIDTH.toPx() * (1f - selectionProgress) }
+                            .padding(start = 16.dp)
+                            .size(24.dp),
+                    )
+                }
+            },
+            {
+                if (isSelectionModeActive) {
+                    // In selection mode the whole row toggles selection.
+                    Box(modifier = Modifier.clickable(enabled = selectionData.canBeSelected, role = Role.Checkbox) {
+                        if (selectableEvent != null) {
+                            onContentClick(selectableEvent)
+                        }
+                    })
+                }
+            },
+        ),
+    ) { (contentMeasurables, indicatorMeasurables, overlayMeasurables), constraints ->
+        val contentPlaceable = contentMeasurables.first().measure(constraints)
+        val width = contentPlaceable.width
+        val height = contentPlaceable.height
+        val indicatorPlaceable = indicatorMeasurables.firstOrNull()?.measure(constraints.copy(minWidth = 0, minHeight = 0))
+        val overlayPlaceable = overlayMeasurables.firstOrNull()?.measure(Constraints.fixed(width, height))
+        layout(width = width, height = height) {
+            contentPlaceable.place(0, 0)
+            if (indicatorPlaceable != null) {
+                val bubbleCenter = contentPlaceable[BubbleVerticalCenter].takeIf { it != AlignmentLine.Unspecified } ?: height / 2
+                val x = if (layoutDirection == LayoutDirection.Ltr) 0 else width - indicatorPlaceable.width
+                indicatorPlaceable.place(x = x, y = bubbleCenter - indicatorPlaceable.height / 2)
+            }
+            overlayPlaceable?.place(0, 0)
+        }
+    }
+}
+
+/** Width reserved for the selection indicator : the row content slides by this amount. */
+private val SELECTION_COLUMN_WIDTH = 36.dp
+
+/**
+ * Whether this item is rendered as a start/end-aligned message bubble, as opposed to a centered
+ * tile (state event, legacy call invite, call/RTC notification, day divider, grouped events).
+ * Mirrors the dispatch in [TimelineItemRowContent]: only bubbles shift to reveal the selection
+ * indicator; centered tiles stay put.
+ */
+private fun TimelineItem.rendersAsBubble(): Boolean = this is TimelineItem.Event &&
+    content !is TimelineItemStateContent &&
+    content !is TimelineItemLegacyCallInviteContent &&
+    content !is TimelineItemRtcNotificationContent
+
+@Suppress("LongMethod")
+@Composable
+private fun TimelineItemRowContent(
+    timelineItem: TimelineItem,
+    timelineMode: Timeline.Mode,
+    timelineRoomInfo: TimelineRoomInfo,
+    isLastOutgoingMessage: Boolean,
+    timelineProtectionState: TimelineProtectionState,
+    focusedEventId: EventId?,
+    displayThreadSummaries: Boolean,
+    onUserDataClick: (MatrixUser) -> Unit,
+    onLinkClick: (Link) -> Unit,
+    onLinkLongClick: (Link) -> Unit,
+    onContentClick: (TimelineItem.Event) -> Unit,
+    onGalleryItemClick: (TimelineItem.Event, Int) -> Unit,
+    onLongClick: (TimelineItem.Event) -> Unit,
+    inReplyToClick: (EventId) -> Unit,
+    onReactionClick: (key: String, TimelineItem.Event) -> Unit,
+    onReactionLongClick: (key: String, TimelineItem.Event) -> Unit,
+    onMoreReactionsClick: (TimelineItem.Event) -> Unit,
+    onReadReceiptClick: (TimelineItem.Event) -> Unit,
+    onJoinCallClick: (isAudioCall: Boolean) -> Unit,
+    onSwipeToReply: (TimelineItem.Event) -> Unit,
+    eventSink: (TimelineEvent.TimelineItemEvent) -> Unit,
+    modifier: Modifier = Modifier,
+    selectionContentOffset: Dp = 0.dp,
+    eventContentView: @Composable (TimelineItem.Event, Modifier, (ContentAvoidingLayoutData) -> Unit) -> Unit,
+) {
+    Box(modifier) {
         when (timelineItem) {
             is TimelineItem.Virtual -> {
                 TimelineItemVirtualRow(
@@ -197,6 +340,7 @@ internal fun TimelineItemRow(
                             onSwipeToReply = { onSwipeToReply(timelineItem) },
                             onGalleryItemClick = { index -> onGalleryItemClick(timelineItem, index) },
                             eventSink = eventSink,
+                            selectionContentOffset = selectionContentOffset,
                             eventContentView = { contentModifier, onContentLayoutChange ->
                                 eventContentView(timelineItem, contentModifier, onContentLayoutChange)
                             },

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/model/TimelineItemSelectionData.kt

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2026 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.messages.impl.timeline.model
+
+/**
+ * Row-scoped selection state passed to [io.element.android.features.messages.impl.timeline.components.TimelineItemRow].
+ *
+ * @param isSelectionModeActive whether the timeline is currently in selection mode. Drives
+ *   behaviour (e.g. the whole-row click target) and must reflect the real mode, not [progress].
+ * @param isSelected whether this specific row's event is part of the current selection.
+ * @param canBeSelected whether this specific row's event can be selected for the action selection mode was entered for.
+ *   Rows which cannot be selected render no indicator and ignore clicks, but their content still slides: sliding only depends on the row being a
+ *   start-aligned bubble, so that the bubbles stay aligned with each other.
+ * @param progress animated 0f..1f value driving the visuals (content slide + indicator slide-in).
+ *   Animated once in TimelineView and shared by every row. Differs from [isSelectionModeActive]
+ *   during the enter/exit animation.
+ */
+data class TimelineItemSelectionData(
+    val isSelectionModeActive: Boolean = false,
+    val isSelected: Boolean = false,
+    val canBeSelected: Boolean = false,
+    val progress: Float = 0f,
+)

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/topbars/SelectionModeTopBar.kt

@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 2026 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.messages.impl.topbars
+
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.pluralStringResource
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.tooling.preview.PreviewParameter
+import androidx.compose.ui.tooling.preview.PreviewParameterProvider
+import io.element.android.compound.tokens.generated.CompoundIcons
+import io.element.android.features.messages.impl.timeline.SelectionAction
+import io.element.android.libraries.designsystem.preview.ElementPreview
+import io.element.android.libraries.designsystem.preview.PreviewsDayNight
+import io.element.android.libraries.designsystem.theme.components.Icon
+import io.element.android.libraries.designsystem.theme.components.IconButton
+import io.element.android.libraries.designsystem.theme.components.Text
+import io.element.android.libraries.designsystem.theme.components.TopAppBar
+import io.element.android.libraries.ui.strings.CommonPlurals
+import io.element.android.libraries.ui.strings.CommonStrings
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun SelectionModeTopBar(
+    selectedCount: Int,
+    action: SelectionAction,
+    onCancelClick: () -> Unit,
+    onConfirmClick: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    TopAppBar(
+        modifier = modifier,
+        title = {
+            Text(text = pluralStringResource(CommonPlurals.common_selected_count, selectedCount, selectedCount))
+        },
+        navigationIcon = {
+            IconButton(
+                onClick = onCancelClick,
+            ) {
+                Icon(imageVector = CompoundIcons.Close(), contentDescription = stringResource(CommonStrings.action_close))
+            }
+        },
+        actions = {
+            IconButton(
+                onClick = onConfirmClick,
+                enabled = selectedCount > 0,
+            ) {
+                Icon(
+                    resourceId = action.iconRes,
+                    contentDescription = stringResource(action.titleRes),
+                )
+            }
+        },
+    )
+}
+
+@PreviewsDayNight
+@Composable
+internal fun SelectionModeTopBarPreview(
+    @PreviewParameter(SelectionCountPreviewParam::class) count: Int,
+) = ElementPreview {
+    SelectionModeTopBar(
+        selectedCount = count,
+        action = SelectionAction.Forward,
+        onCancelClick = {},
+        onConfirmClick = {},
+    )
+}
+
+internal class SelectionCountPreviewParam : PreviewParameterProvider<Int> {
+    override val values = sequenceOf(0, 1, 5)
+}

features/messages/impl/src/test/kotlin/io/element/android/features/messages/impl/FakeMessagesNavigator.kt

@@ -20,7 +20,7 @@ import kotlinx.collections.immutable.ImmutableList
 
 class FakeMessagesNavigator(
     private val onShowEventDebugInfoClickLambda: (eventId: EventId?, debugInfo: TimelineItemDebugInfo) -> Unit = { _, _ -> lambdaError() },
-    private val onForwardEventClickLambda: (eventId: EventId, timelineProvider: TimelineProvider) -> Unit = { _, _ -> lambdaError() },
+    private val onForwardEventClickLambda: (eventIds: List<EventId>, timelineProvider: TimelineProvider) -> Unit = { _, _ -> lambdaError() },
     private val onReportContentClickLambda: (eventId: EventId, senderId: UserId) -> Unit = { _, _ -> lambdaError() },
     private val onEditPollClickLambda: (eventId: EventId) -> Unit = { _ -> lambdaError() },
     private val onPreviewAttachmentLambda: (attachments: ImmutableList<Attachment>, inReplyToEventId: EventId?) -> Unit = { _, _ -> lambdaError() },
@@ -35,8 +35,8 @@ class FakeMessagesNavigator(
         onShowEventDebugInfoClickLambda(eventId, debugInfo)
     }
 
-    override fun forwardEvent(eventId: EventId, timelineProvider: TimelineProvider) {
-        onForwardEventClickLambda(eventId, timelineProvider)
+    override fun forwardEvents(eventIds: List<EventId>, timelineProvider: TimelineProvider) {
+        onForwardEventClickLambda(eventIds, timelineProvider)
     }
 
     override fun navigateToReportMessage(eventId: EventId, senderId: UserId) {

features/messages/impl/src/test/kotlin/io/element/android/features/messages/impl/MessagesPresenterTest.kt

@@ -28,8 +28,12 @@ import io.element.android.features.messages.impl.pinned.banner.aLoadedPinnedMess
 import io.element.android.features.messages.impl.threads.list.aThreadListItem
 import io.element.android.features.messages.impl.timeline.FakeMarkAsFullyRead
 import io.element.android.features.messages.impl.timeline.MarkAsFullyRead
+import io.element.android.features.messages.impl.timeline.SelectionAction
+import io.element.android.features.messages.impl.timeline.SelectionState
 import io.element.android.features.messages.impl.timeline.TimelineController
 import io.element.android.features.messages.impl.timeline.TimelineEvent
+import io.element.android.features.messages.impl.timeline.TimelineState
+import io.element.android.features.messages.impl.timeline.aTimelineItemEvent
 import io.element.android.features.messages.impl.timeline.aTimelineState
 import io.element.android.features.messages.impl.timeline.model.TimelineItemThreadInfo
 import io.element.android.features.messages.impl.timeline.model.event.TimelineItemFileContent
@@ -78,6 +82,7 @@ import io.element.android.libraries.matrix.api.timeline.item.event.LocalEventSen
 import io.element.android.libraries.matrix.api.timeline.item.event.toEventOrTransactionId
 import io.element.android.libraries.matrix.test.AN_AVATAR_URL
 import io.element.android.libraries.matrix.test.AN_EVENT_ID
+import io.element.android.libraries.matrix.test.AN_EVENT_ID_2
 import io.element.android.libraries.matrix.test.AN_EXCEPTION
 import io.element.android.libraries.matrix.test.A_CAPTION
 import io.element.android.libraries.matrix.test.A_REASON
@@ -118,6 +123,7 @@ import io.element.android.tests.testutils.lambda.value
 import io.element.android.tests.testutils.testCoroutineDispatchers
 import io.element.android.tests.testutils.testWithLifecycleOwner
 import kotlinx.collections.immutable.persistentListOf
+import kotlinx.collections.immutable.persistentSetOf
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.MutableStateFlow
@@ -289,17 +295,37 @@ class MessagesPresenterTest {
     }
 
     @Test
-    fun `present - handle action forward`() = runTest {
-        val onForwardEventClickLambda = lambdaRecorder<EventId, TimelineProvider, Unit> { _, _ -> }
-        val navigator = FakeMessagesNavigator(
-            onForwardEventClickLambda = onForwardEventClickLambda,
+    fun `present - handle action forward enters selection mode when multi select is enabled`() = runTest {
+        val timelineEventSink = lambdaRecorder<TimelineEvent, Unit> { }
+        val presenter = createMessagesPresenter(
+            timelineEventSink = timelineEventSink,
+            featureFlagService = FakeFeatureFlagService(initialState = mapOf(FeatureFlags.MessageMultiSelect.key to true)),
         )
-        val presenter = createMessagesPresenter(navigator = navigator)
         presenter.testWithLifecycleOwner {
             val initialState = awaitItem()
             initialState.eventSink(MessagesEvent.HandleAction(TimelineItemAction.Forward, aMessageEvent()))
             assertThat(awaitItem().actionListState.target).isEqualTo(ActionListState.Target.None)
-            onForwardEventClickLambda.assertions().isCalledOnce().with(value(AN_EVENT_ID), any())
+            timelineEventSink.assertions().isCalledOnce()
+                .with(value(TimelineEvent.EnterSelectionMode(SelectionAction.Forward, AN_EVENT_ID)))
+            cancelAndIgnoreRemainingEvents()
+        }
+    }
+
+    @Test
+    fun `present - handle action forward navigates directly when multi select is disabled`() = runTest {
+        val onForwardEventClickLambda = lambdaRecorder<List<EventId>, TimelineProvider, Unit> { _, _ -> }
+        val navigator = FakeMessagesNavigator(
+            onForwardEventClickLambda = onForwardEventClickLambda,
+        )
+        val presenter = createMessagesPresenter(
+            navigator = navigator,
+            featureFlagService = FakeFeatureFlagService(initialState = mapOf(FeatureFlags.MessageMultiSelect.key to false)),
+        )
+        presenter.testWithLifecycleOwner {
+            val initialState = awaitItem()
+            initialState.eventSink(MessagesEvent.HandleAction(TimelineItemAction.Forward, aMessageEvent()))
+            assertThat(awaitItem().actionListState.target).isEqualTo(ActionListState.Target.None)
+            onForwardEventClickLambda.assertions().isCalledOnce().with(value(listOf(AN_EVENT_ID)), any())
         }
     }
 
@@ -1501,6 +1527,49 @@ class MessagesPresenterTest {
         canPinUnpin = canPinUnpin,
     )
 
+    @Test
+    fun `present - confirm selection action forwards the selection in timeline order`() = runTest {
+        val onForwardEventClickLambda = lambdaRecorder<List<EventId>, TimelineProvider, Unit> { _, _ -> }
+        val navigator = FakeMessagesNavigator(onForwardEventClickLambda = onForwardEventClickLambda)
+        val timelineEventSink = lambdaRecorder<TimelineEvent, Unit> { }
+        val presenter = createMessagesPresenter(
+            navigator = navigator,
+            timelineEventSink = timelineEventSink,
+            timelineState = aTimelineState(
+                // The timeline is rendered from the most recent event to the oldest one.
+                timelineItems = persistentListOf(
+                    aTimelineItemEvent(eventId = AN_EVENT_ID_2),
+                    aTimelineItemEvent(eventId = AN_EVENT_ID),
+                ),
+                selectionState = SelectionState.Active(
+                    SelectionAction.Forward,
+                    persistentSetOf(AN_EVENT_ID_2, AN_EVENT_ID),
+                ),
+                eventSink = timelineEventSink,
+            ),
+        )
+        presenter.testWithLifecycleOwner {
+            val initialState = awaitItem()
+            initialState.eventSink(MessagesEvent.ConfirmSelectionAction)
+            onForwardEventClickLambda.assertions().isCalledOnce().with(value(listOf(AN_EVENT_ID, AN_EVENT_ID_2)), any())
+            timelineEventSink.assertions().isCalledOnce().with(value(TimelineEvent.ExitSelectionMode))
+            cancelAndIgnoreRemainingEvents()
+        }
+    }
+
+    @Test
+    fun `present - confirm selection action does nothing when no selection is active`() = runTest {
+        val onForwardEventClickLambda = lambdaRecorder<List<EventId>, TimelineProvider, Unit> { _, _ -> }
+        val navigator = FakeMessagesNavigator(onForwardEventClickLambda = onForwardEventClickLambda)
+        val presenter = createMessagesPresenter(navigator = navigator)
+        presenter.testWithLifecycleOwner {
+            val initialState = awaitItem()
+            initialState.eventSink(MessagesEvent.ConfirmSelectionAction)
+            onForwardEventClickLambda.assertions().isNeverCalled()
+            cancelAndIgnoreRemainingEvents()
+        }
+    }
+
     private fun TestScope.createMessagesPresenter(
         coroutineDispatchers: CoroutineDispatchers = testCoroutineDispatchers(),
         timeline: Timeline = FakeTimeline(),
@@ -1523,6 +1592,7 @@ class MessagesPresenterTest {
         clipboardHelper: FakeClipboardHelper = FakeClipboardHelper(),
         analyticsService: FakeAnalyticsService = FakeAnalyticsService(),
         timelineEventSink: (TimelineEvent) -> Unit = {},
+        timelineState: TimelineState = aTimelineState(eventSink = timelineEventSink),
         permalinkParser: PermalinkParser = FakePermalinkParser(),
         messageComposerPresenter: Presenter<MessageComposerState> = Presenter {
             aMessageComposerState(
@@ -1545,7 +1615,7 @@ class MessagesPresenterTest {
             room = joinedRoom,
             composerPresenter = messageComposerPresenter,
             voiceMessageComposerPresenterFactory = FakeDefaultVoiceMessageComposerPresenterFactory(backgroundScope),
-            timelinePresenter = { aTimelineState(eventSink = timelineEventSink) },
+            timelinePresenter = { timelineState },
             timelineProtectionPresenter = { aTimelineProtectionState() },
             identityChangeStatePresenter = { anIdentityChangeState() },
             linkPresenter = { aLinkState() },

features/messages/impl/src/test/kotlin/io/element/android/features/messages/impl/timeline/SelectionActionTest.kt

@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2026 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.messages.impl.timeline
+
+import com.google.common.truth.Truth.assertThat
+import io.element.android.features.messages.impl.timeline.model.event.aStaticLocationMode
+import io.element.android.features.messages.impl.timeline.model.event.aTimelineItemLocationContent
+import io.element.android.features.messages.impl.timeline.model.event.aTimelineItemRedactedContent
+import io.element.android.features.messages.impl.timeline.model.event.aTimelineItemStateEventContent
+import io.element.android.features.messages.impl.timeline.model.event.aTimelineItemStickerContent
+import io.element.android.libraries.matrix.api.timeline.item.event.LocalEventSendState
+import org.junit.Test
+
+class SelectionActionTest {
+    @Test
+    fun `Forward - a remote text message can be selected`() {
+        assertThat(SelectionAction.Forward.canApplyTo(aTimelineItemEvent())).isTrue()
+    }
+
+    @Test
+    fun `Forward - a local echo cannot be selected`() {
+        assertThat(SelectionAction.Forward.canApplyTo(aTimelineItemEvent().copy(eventId = null))).isFalse()
+    }
+
+    @Test
+    fun `Forward - a failed to send message cannot be selected`() {
+        // A message which failed to send is a local echo: it has no event id.
+        val item = aTimelineItemEvent(sendState = LocalEventSendState.Failed.Unknown("failed")).copy(eventId = null)
+        assertThat(SelectionAction.Forward.canApplyTo(item)).isFalse()
+    }
+
+    @Test
+    fun `Forward - a state event cannot be selected`() {
+        val item = aTimelineItemEvent(content = aTimelineItemStateEventContent())
+        assertThat(SelectionAction.Forward.canApplyTo(item)).isFalse()
+    }
+
+    @Test
+    fun `Forward - a redacted event cannot be selected`() {
+        val item = aTimelineItemEvent(content = aTimelineItemRedactedContent())
+        assertThat(SelectionAction.Forward.canApplyTo(item)).isFalse()
+    }
+
+    @Test
+    fun `Forward - a sticker cannot be selected, it cannot be forwarded`() {
+        val item = aTimelineItemEvent(content = aTimelineItemStickerContent())
+        assertThat(SelectionAction.Forward.canApplyTo(item)).isFalse()
+    }
+
+    @Test
+    fun `Forward - a static location can be selected, it can be forwarded`() {
+        val item = aTimelineItemEvent(content = aTimelineItemLocationContent(mode = aStaticLocationMode()))
+        assertThat(SelectionAction.Forward.canApplyTo(item)).isTrue()
+    }
+}

features/messages/impl/src/test/kotlin/io/element/android/features/messages/impl/timeline/SelectionStateTest.kt

@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) 2026 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.messages.impl.timeline
+
+import com.google.common.truth.Truth.assertThat
+import io.element.android.features.messages.impl.timeline.model.TimelineItem
+import io.element.android.features.messages.impl.timeline.model.event.aTimelineItemRedactedContent
+import io.element.android.libraries.matrix.api.core.EventId
+import io.element.android.libraries.matrix.api.core.UniqueId
+import io.element.android.libraries.matrix.test.AN_EVENT_ID
+import io.element.android.libraries.matrix.test.AN_EVENT_ID_2
+import io.element.android.libraries.matrix.test.AN_EVENT_ID_3
+import kotlinx.collections.immutable.persistentListOf
+import kotlinx.collections.immutable.toImmutableSet
+import org.junit.Test
+
+class SelectionStateTest {
+    @Test
+    fun `eventIdsToDeselect - selection mode being disabled has nothing to drop`() {
+        val items = listOf(aTimelineItemEvent(eventId = AN_EVENT_ID, content = aTimelineItemRedactedContent()))
+        assertThat(SelectionState.Disabled.eventIdsToDeselect(items)).isEmpty()
+    }
+
+    @Test
+    fun `eventIdsToDeselect - an empty selection has nothing to drop`() {
+        val items = listOf(aTimelineItemEvent(eventId = AN_EVENT_ID, content = aTimelineItemRedactedContent()))
+        assertThat(anActiveSelection().eventIdsToDeselect(items)).isEmpty()
+    }
+
+    @Test
+    fun `eventIdsToDeselect - a selected event the action still applies to is kept`() {
+        val items = listOf(aTimelineItemEvent(eventId = AN_EVENT_ID))
+        assertThat(anActiveSelection(listOf(AN_EVENT_ID)).eventIdsToDeselect(items)).isEmpty()
+    }
+
+    @Test
+    fun `eventIdsToDeselect - a selected event which has been deleted is dropped`() {
+        val items = listOf(
+            aTimelineItemEvent(eventId = AN_EVENT_ID_2, content = aTimelineItemRedactedContent()),
+            aTimelineItemEvent(eventId = AN_EVENT_ID),
+        )
+        assertThat(anActiveSelection(listOf(AN_EVENT_ID, AN_EVENT_ID_2)).eventIdsToDeselect(items)).containsExactly(AN_EVENT_ID_2)
+    }
+
+    @Test
+    fun `eventIdsToDeselect - a selected event which is not in the timeline is ignored`() {
+        val items = listOf(aTimelineItemEvent(eventId = AN_EVENT_ID))
+        // AN_EVENT_ID_3 may simply not be loaded anymore, so it is not dropped here.
+        assertThat(anActiveSelection(listOf(AN_EVENT_ID, AN_EVENT_ID_3)).eventIdsToDeselect(items)).isEmpty()
+    }
+
+    @Test
+    fun `eventIdsToDeselect - a deleted selected event folded into a group is dropped`() {
+        val items = listOf(
+            TimelineItem.GroupedEvents(
+                id = UniqueId("group"),
+                events = persistentListOf(
+                    aTimelineItemEvent(eventId = AN_EVENT_ID_2, content = aTimelineItemRedactedContent()),
+                    aTimelineItemEvent(eventId = AN_EVENT_ID_3, content = aTimelineItemRedactedContent()),
+                ),
+                aggregatedReadReceipts = persistentListOf(),
+            ),
+            aTimelineItemEvent(eventId = AN_EVENT_ID),
+        )
+        assertThat(anActiveSelection(listOf(AN_EVENT_ID, AN_EVENT_ID_2)).eventIdsToDeselect(items)).containsExactly(AN_EVENT_ID_2)
+    }
+
+    @Test
+    fun `deselect - removes the given events and keeps selection mode active`() {
+        val selection = anActiveSelection(listOf(AN_EVENT_ID, AN_EVENT_ID_2))
+        assertThat(selection.deselect(setOf(AN_EVENT_ID))).isEqualTo(anActiveSelection(listOf(AN_EVENT_ID_2)))
+        assertThat(selection.deselect(setOf(AN_EVENT_ID, AN_EVENT_ID_2))).isEqualTo(anActiveSelection())
+    }
+
+    @Test
+    fun `deselect - does nothing when selection mode is disabled`() {
+        assertThat(SelectionState.Disabled.deselect(setOf(AN_EVENT_ID))).isEqualTo(SelectionState.Disabled)
+    }
+
+    private fun anActiveSelection(eventIds: List<EventId> = emptyList()) = SelectionState.Active(
+        action = SelectionAction.Forward,
+        selectedEventIds = eventIds.toImmutableSet(),
+    )
+}

features/messages/impl/src/test/kotlin/io/element/android/features/messages/impl/timeline/TimelinePresenterTest.kt

@@ -38,6 +38,7 @@ import io.element.android.libraries.androidutils.clipboard.FakeClipboardHelper
 import io.element.android.libraries.androidutils.toast.FakeToastHelper
 import io.element.android.libraries.androidutils.toast.ToastHelper
 import io.element.android.libraries.architecture.Presenter
+import io.element.android.libraries.designsystem.utils.snackbar.SnackbarDispatcher
 import io.element.android.libraries.featureflag.api.FeatureFlags
 import io.element.android.libraries.featureflag.test.FakeFeatureFlagService
 import io.element.android.libraries.matrix.api.core.EventId
@@ -91,6 +92,7 @@ import io.element.android.tests.testutils.lambda.value
 import io.element.android.tests.testutils.test
 import io.element.android.tests.testutils.testCoroutineDispatchers
 import kotlinx.collections.immutable.persistentListOf
+import kotlinx.collections.immutable.persistentSetOf
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.FlowPreview
 import kotlinx.coroutines.delay
@@ -1861,6 +1863,152 @@ class TimelinePresenterTest {
         }
     }
 
+    @Test
+    fun `present - entering selection mode selects the target event`() = runTest {
+        val timelineItems = MutableStateFlow(
+            listOf(MatrixTimelineItem.Event(UniqueId("1"), anEventTimelineItem(eventId = AN_EVENT_ID, content = aMessageContent())))
+        )
+        val presenter = createTimelinePresenter(
+            timeline = FakeTimeline(timelineItems = timelineItems),
+            featureFlagService = FakeFeatureFlagService(initialState = mapOf(FeatureFlags.MessageMultiSelect.key to true)),
+        )
+        presenter.test {
+            val initialState = consumeItemsUntilPredicate { it.hasAnyEvent }.last()
+            assertThat(initialState.selectionState).isEqualTo(SelectionState.Disabled)
+            initialState.eventSink(TimelineEvent.EnterSelectionMode(SelectionAction.Forward, AN_EVENT_ID))
+            val state = consumeItemsUntilPredicate { it.isSelectionModeActive }.last()
+            assertThat(state.selectionState).isEqualTo(SelectionState.Active(SelectionAction.Forward, persistentSetOf(AN_EVENT_ID)))
+            assertThat(state.selectedCount).isEqualTo(1)
+            cancelAndIgnoreRemainingEvents()
+        }
+    }
+
+    @Test
+    fun `present - entering selection mode is ignored when the flag is off`() = runTest {
+        val featureFlagService = FakeFeatureFlagService(initialState = mapOf(FeatureFlags.MessageMultiSelect.key to false))
+        val presenter = createTimelinePresenter(featureFlagService = featureFlagService)
+        presenter.test {
+            val initialState = awaitFirstItem()
+            initialState.eventSink(TimelineEvent.EnterSelectionMode(SelectionAction.Forward, AN_EVENT_ID))
+            expectNoEvents()
+            assertThat(initialState.selectionState).isEqualTo(SelectionState.Disabled)
+            cancelAndIgnoreRemainingEvents()
+        }
+    }
+
+    @Test
+    fun `present - toggling the last selected event keeps selection mode active`() = runTest {
+        val timelineItems = MutableStateFlow(
+            listOf(MatrixTimelineItem.Event(UniqueId("1"), anEventTimelineItem(eventId = AN_EVENT_ID, content = aMessageContent())))
+        )
+        val presenter = createTimelinePresenter(
+            timeline = FakeTimeline(timelineItems = timelineItems),
+            featureFlagService = FakeFeatureFlagService(initialState = mapOf(FeatureFlags.MessageMultiSelect.key to true)),
+        )
+        presenter.test {
+            val initialState = consumeItemsUntilPredicate { it.hasAnyEvent }.last()
+            initialState.eventSink(TimelineEvent.EnterSelectionMode(SelectionAction.Forward, AN_EVENT_ID))
+            consumeItemsUntilPredicate { it.isSelectionModeActive }
+            initialState.eventSink(TimelineEvent.ToggleSelection(AN_EVENT_ID))
+            // Selection mode is only exited explicitly, so an empty selection keeps it active.
+            val state = consumeItemsUntilPredicate { it.selectedCount == 0 }.last()
+            assertThat(state.selectionState).isEqualTo(SelectionState.Active(SelectionAction.Forward, persistentSetOf()))
+            assertThat(state.isSelectionModeActive).isTrue()
+            cancelAndIgnoreRemainingEvents()
+        }
+    }
+
+    @Test
+    fun `present - exiting selection mode clears the selection`() = runTest {
+        val timelineItems = MutableStateFlow(
+            listOf(MatrixTimelineItem.Event(UniqueId("1"), anEventTimelineItem(eventId = AN_EVENT_ID, content = aMessageContent())))
+        )
+        val presenter = createTimelinePresenter(
+            timeline = FakeTimeline(timelineItems = timelineItems),
+            featureFlagService = FakeFeatureFlagService(initialState = mapOf(FeatureFlags.MessageMultiSelect.key to true)),
+        )
+        presenter.test {
+            val initialState = consumeItemsUntilPredicate { it.hasAnyEvent }.last()
+            initialState.eventSink(TimelineEvent.EnterSelectionMode(SelectionAction.Forward, AN_EVENT_ID))
+            consumeItemsUntilPredicate { it.isSelectionModeActive }
+            initialState.eventSink(TimelineEvent.ExitSelectionMode)
+            val state = consumeItemsUntilPredicate { !it.isSelectionModeActive }.last()
+            assertThat(state.selectionState).isEqualTo(SelectionState.Disabled)
+            cancelAndIgnoreRemainingEvents()
+        }
+    }
+
+    @Test
+    fun `present - turning the flag off clears the active selection`() = runTest {
+        val timelineItems = MutableStateFlow(
+            listOf(MatrixTimelineItem.Event(UniqueId("1"), anEventTimelineItem(eventId = AN_EVENT_ID, content = aMessageContent())))
+        )
+        val featureFlagService = FakeFeatureFlagService(initialState = mapOf(FeatureFlags.MessageMultiSelect.key to true))
+        val presenter = createTimelinePresenter(
+            timeline = FakeTimeline(timelineItems = timelineItems),
+            featureFlagService = featureFlagService,
+        )
+        presenter.test {
+            val initialState = consumeItemsUntilPredicate { it.hasAnyEvent }.last()
+            initialState.eventSink(TimelineEvent.EnterSelectionMode(SelectionAction.Forward, AN_EVENT_ID))
+            consumeItemsUntilPredicate { it.isSelectionModeActive }
+            featureFlagService.setFeatureEnabled(FeatureFlags.MessageMultiSelect, false)
+            val state = consumeItemsUntilPredicate { !it.isSelectionModeActive }.last()
+            assertThat(state.selectionState).isEqualTo(SelectionState.Disabled)
+            cancelAndIgnoreRemainingEvents()
+        }
+    }
+
+    @Test
+    fun `present - a selected event which cannot be forwarded anymore is deselected`() = runTest {
+        val timelineItems = MutableStateFlow(
+            listOf(
+                MatrixTimelineItem.Event(UniqueId("1"), anEventTimelineItem(eventId = AN_EVENT_ID, content = aMessageContent())),
+                MatrixTimelineItem.Event(UniqueId("2"), anEventTimelineItem(eventId = AN_EVENT_ID_2, content = aMessageContent())),
+            )
+        )
+        val presenter = createTimelinePresenter(
+            timeline = FakeTimeline(timelineItems = timelineItems),
+            featureFlagService = FakeFeatureFlagService(initialState = mapOf(FeatureFlags.MessageMultiSelect.key to true)),
+        )
+        presenter.test {
+            val initialState = consumeItemsUntilPredicate { it.hasAnyEvent }.last()
+            initialState.eventSink(TimelineEvent.EnterSelectionMode(SelectionAction.Forward, AN_EVENT_ID))
+            initialState.eventSink(TimelineEvent.ToggleSelection(AN_EVENT_ID_2))
+            consumeItemsUntilPredicate { it.selectedCount == 2 }
+            // The first message is deleted, so it cannot be forwarded anymore.
+            timelineItems.value = listOf(
+                MatrixTimelineItem.Event(UniqueId("1"), anEventTimelineItem(eventId = AN_EVENT_ID, content = aRedactedContent())),
+                MatrixTimelineItem.Event(UniqueId("2"), anEventTimelineItem(eventId = AN_EVENT_ID_2, content = aMessageContent())),
+            )
+            val state = consumeItemsUntilPredicate { it.selectedCount == 1 }.last()
+            assertThat(state.selectionState).isEqualTo(SelectionState.Active(SelectionAction.Forward, persistentSetOf(AN_EVENT_ID_2)))
+            cancelAndIgnoreRemainingEvents()
+        }
+    }
+
+    @Test
+    fun `present - the selection survives a timeline which no longer contains the selected event`() = runTest {
+        val timelineItems = MutableStateFlow(
+            listOf(MatrixTimelineItem.Event(UniqueId("1"), anEventTimelineItem(eventId = AN_EVENT_ID, content = aMessageContent())))
+        )
+        val presenter = createTimelinePresenter(
+            timeline = FakeTimeline(timelineItems = timelineItems),
+            featureFlagService = FakeFeatureFlagService(initialState = mapOf(FeatureFlags.MessageMultiSelect.key to true)),
+        )
+        presenter.test {
+            val initialState = consumeItemsUntilPredicate { it.hasAnyEvent }.last()
+            initialState.eventSink(TimelineEvent.EnterSelectionMode(SelectionAction.Forward, AN_EVENT_ID))
+            consumeItemsUntilPredicate { it.isSelectionModeActive }
+            // The timeline no longer holds the selected event, for instance because it has been reset or because it switched to a detached timeline.
+            timelineItems.value = emptyList()
+            val state = consumeItemsUntilPredicate { !it.hasAnyEvent }.last()
+            // The selection is the user intent: it is only validated when the action is confirmed, so that a transient timeline update cannot drop it.
+            assertThat(state.selectionState).isEqualTo(SelectionState.Active(SelectionAction.Forward, persistentSetOf(AN_EVENT_ID)))
+            cancelAndIgnoreRemainingEvents()
+        }
+    }
+
     private suspend fun <T> ReceiveTurbine<T>.awaitFirstItem(): T {
         return awaitItem()
     }
@@ -1958,6 +2106,7 @@ class TimelinePresenterTest {
             typingNotificationPresenter = { aTypingNotificationState() },
             roomCallStatePresenter = { aStandByCallState() },
             featureFlagService = featureFlagService,
+            snackbarDispatcher = SnackbarDispatcher(),
             analyticsService = FakeAnalyticsService(),
             liveLocationShareManager = liveLocationShareManager,
             markAsFullyRead = markAsFullyRead,

features/messages/impl/src/test/kotlin/io/element/android/features/messages/impl/timeline/TimelineStateTest.kt

@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2026 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.features.messages.impl.timeline
+
+import com.google.common.truth.Truth.assertThat
+import io.element.android.features.messages.impl.timeline.model.event.aTimelineItemRedactedContent
+import io.element.android.libraries.matrix.test.AN_EVENT_ID
+import io.element.android.libraries.matrix.test.AN_EVENT_ID_2
+import io.element.android.libraries.matrix.test.AN_EVENT_ID_3
+import kotlinx.collections.immutable.persistentListOf
+import kotlinx.collections.immutable.persistentSetOf
+import org.junit.Test
+
+class TimelineStateTest {
+    @Test
+    fun `selectedEventIdsInTimelineOrder - when selection is disabled, the list is empty`() {
+        val state = aTimelineState(
+            timelineItems = persistentListOf(aTimelineItemEvent(eventId = AN_EVENT_ID)),
+            selectionState = SelectionState.Disabled,
+        )
+        assertThat(state.selectedEventIdsInTimelineOrder()).isEmpty()
+    }
+
+    @Test
+    fun `selectedEventIdsInTimelineOrder - the events are sorted from the oldest to the most recent one`() {
+        // The timeline items are rendered from the most recent to the oldest event.
+        val state = aTimelineState(
+            timelineItems = persistentListOf(
+                aTimelineItemEvent(eventId = AN_EVENT_ID_3),
+                aTimelineItemEvent(eventId = AN_EVENT_ID_2),
+                aTimelineItemEvent(eventId = AN_EVENT_ID),
+            ),
+            // The events have been tapped in a random order.
+            selectionState = SelectionState.Active(SelectionAction.Forward, persistentSetOf(AN_EVENT_ID_2, AN_EVENT_ID, AN_EVENT_ID_3)),
+        )
+        assertThat(state.selectedEventIdsInTimelineOrder()).containsExactly(AN_EVENT_ID, AN_EVENT_ID_2, AN_EVENT_ID_3).inOrder()
+    }
+
+    @Test
+    fun `selectedEventIdsInTimelineOrder - the events which are not in the timeline are ignored`() {
+        val state = aTimelineState(
+            timelineItems = persistentListOf(
+                aTimelineItemEvent(eventId = AN_EVENT_ID_2),
+                aTimelineItemEvent(eventId = AN_EVENT_ID),
+            ),
+            selectionState = SelectionState.Active(SelectionAction.Forward, persistentSetOf(AN_EVENT_ID_2, AN_EVENT_ID_3)),
+        )
+        assertThat(state.selectedEventIdsInTimelineOrder()).containsExactly(AN_EVENT_ID_2)
+    }
+
+    @Test
+    fun `canSelect - returns false when selection mode is disabled`() {
+        val event = aTimelineItemEvent(eventId = AN_EVENT_ID)
+        val state = aTimelineState(
+            timelineItems = persistentListOf(event),
+            selectionState = SelectionState.Disabled,
+        )
+        assertThat(state.canSelect(event)).isFalse()
+    }
+
+    @Test
+    fun `canSelect - follows the action predicate when selection mode is active`() {
+        val forwardable = aTimelineItemEvent(eventId = AN_EVENT_ID)
+        val notForwardable = aTimelineItemEvent(eventId = AN_EVENT_ID_2, content = aTimelineItemRedactedContent())
+        val state = aTimelineState(
+            timelineItems = persistentListOf(forwardable, notForwardable),
+            selectionState = SelectionState.Active(SelectionAction.Forward, persistentSetOf(AN_EVENT_ID)),
+        )
+        assertThat(state.canSelect(forwardable)).isTrue()
+        assertThat(state.canSelect(notForwardable)).isFalse()
+    }
+}

libraries/featureflag/api/src/main/kotlin/io/element/android/libraries/featureflag/api/FeatureFlags.kt

@@ -154,6 +154,14 @@ enum class FeatureFlags(
         defaultValue = { false },
         isFinished = false,
     ),
+    MessageMultiSelect(
+        key = "feature.message_multi_select",
+        title = "Multi-select messages",
+        description = "The Forward action enters a selection mode, to pick and forward up to 10 messages at once.",
+        defaultValue = { false },
+        isFinished = false,
+        isInLabs = false,
+    ),
     NewTimelineEventRenderer(
         key = "feature.new_timeline_event_renderer",
         title = "New timeline event renderer",

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/timeline/Timeline.kt

@@ -316,12 +316,13 @@ interface Timeline : AutoCloseable {
     suspend fun toggleReaction(emoji: String, eventOrTransactionId: EventOrTransactionId): Result<Boolean>
 
     /**
-     * Forwards the content of an event to other rooms, as new messages sent by the current user.
+     * Forwards the content of some events to other rooms, as new messages sent by the current user.
+     * The events are forwarded in the order of [eventIds].
      *
-     * @param eventId the event whose content is forwarded.
-     * @param roomIds the rooms to forward it to.
+     * @param eventIds the events whose content is forwarded.
+     * @param roomIds the rooms to forward them to.
      */
-    suspend fun forwardEvent(eventId: EventId, roomIds: List<RoomId>): Result<Unit>
+    suspend fun forwardEvents(eventIds: List<EventId>, roomIds: List<RoomId>): Result<Unit>
 
     /**
      * Cancels an event that is still waiting in the send queue, by redacting its local echo.

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/room/RoomContentForwarder.kt

@@ -14,7 +14,6 @@ import io.element.android.libraries.matrix.api.core.EventId
 import io.element.android.libraries.matrix.api.core.RoomId
 import io.element.android.libraries.matrix.api.room.ForwardEventException
 import io.element.android.libraries.matrix.impl.roomlist.roomOrNull
-import io.element.android.libraries.matrix.impl.timeline.runWithTimelineListenerRegistered
 import kotlinx.coroutines.withTimeout
 import org.matrix.rustcomponents.sdk.MsgLikeKind
 import org.matrix.rustcomponents.sdk.RoomListService
@@ -31,33 +30,36 @@ class RoomContentForwarder(
     private val roomListService: RoomListService,
 ) {
     /**
-     * Forwards the event with the given [eventId] from the [fromTimeline] to the given [toRoomIds].
-     * @param fromTimeline the room to forward the event from
-     * @param eventId the id of the event to forward
-     * @param toRoomIds the ids of the rooms to forward the event to
-     * @param timeoutMs the maximum time in milliseconds to wait for the event to be sent to a room
+     * Forwards the events with the given [eventIds] from the [fromTimeline] to the given [toRoomIds].
+     * The events are sent to each room in the order they are provided in [eventIds], it is up to the caller to sort them.
+     * @param fromTimeline the room to forward the events from
+     * @param eventIds the ids of the events to forward, in the order they must be sent
+     * @param toRoomIds the ids of the rooms to forward the events to
+     * @param timeoutMs the maximum time in milliseconds to wait for an event to be sent to a room
      */
     suspend fun forward(
         fromTimeline: Timeline,
-        eventId: EventId,
+        eventIds: List<EventId>,
         toRoomIds: List<RoomId>,
         timeoutMs: Long = 5000L
     ) {
-        val messageLikeContent = (fromTimeline.getEventTimelineItemByEventId(eventId.value).content as? TimelineItemContent.MsgLike)?.content
-            ?: throw ForwardEventException(toRoomIds)
-
-        val content = (messageLikeContent.kind as? MsgLikeKind.Message)?.content
-            ?: throw ForwardEventException(toRoomIds)
-
+        val contents = eventIds.map { eventId ->
+            val timelineEvent = fromTimeline.getEventTimelineItemByEventId(eventId.value)
+            val content = timelineEvent.content as? TimelineItemContent.MsgLike ?: throw ForwardEventException(toRoomIds)
+            val message = content.content.kind as? MsgLikeKind.Message ?: throw ForwardEventException(toRoomIds)
+            contentWithoutRelationFromMessage(message.content)
+        }
         val targetRooms = toRoomIds.toSet().mapNotNull { roomId -> roomListService.roomOrNull(roomId.value) }
         val failedForwardingTo = mutableSetOf<RoomId>()
         targetRooms.parallelMap { room ->
             room.use { targetRoom ->
                 runCatchingExceptions {
-                    // Sending a message requires a registered timeline listener
-                    targetRoom.timeline().runWithTimelineListenerRegistered {
-                        withTimeout(timeoutMs.milliseconds) {
-                            targetRoom.timeline().send(contentWithoutRelationFromMessage(content))
+                    targetRoom.timeline().use { timeline ->
+                        // Send the contents sequentially, so that they are received in the same order
+                        contents.forEach { content ->
+                            withTimeout(timeoutMs.milliseconds) {
+                                timeline.send(content)
+                            }
                         }
                     }
                 }

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/timeline/RoomTimelineExtensions.kt

@@ -53,16 +53,3 @@ internal fun TimelineInterface.timelineDiffFlow(): Flow<List<TimelineDiff>> =
     }.catch {
         Timber.d(it, "timelineDiffFlow() failed")
     }.buffer(Channel.UNLIMITED)
-
-internal suspend fun TimelineInterface.runWithTimelineListenerRegistered(action: suspend () -> Unit) {
-    val result = addListener(NoOpTimelineListener)
-    try {
-        action()
-    } finally {
-        result.cancelAndDestroy()
-    }
-}
-
-private object NoOpTimelineListener : TimelineListener {
-    override fun onUpdate(diff: List<TimelineDiff>) = Unit
-}

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/timeline/RustTimeline.kt

@@ -489,9 +489,9 @@ class RustTimeline(
         }
     }
 
-    override suspend fun forwardEvent(eventId: EventId, roomIds: List<RoomId>): Result<Unit> = withContext(dispatcher) {
+    override suspend fun forwardEvents(eventIds: List<EventId>, roomIds: List<RoomId>): Result<Unit> = withContext(dispatcher) {
         runCatchingExceptions {
-            roomContentForwarder.forward(fromTimeline = inner, eventId = eventId, toRoomIds = roomIds)
+            roomContentForwarder.forward(fromTimeline = inner, eventIds = eventIds, toRoomIds = roomIds)
         }.onFailure {
             Timber.tag(loggerTag).e(it)
         }

libraries/matrix/test/src/main/kotlin/io/element/android/libraries/matrix/test/timeline/FakeTimeline.kt

@@ -355,10 +355,10 @@ class FakeTimeline(
         )
     }
 
-    var forwardEventLambda: (eventId: EventId, roomIds: List<RoomId>) -> Result<Unit> = { _, _ -> lambdaError() }
+    var forwardEventsLambda: (eventIds: List<EventId>, roomIds: List<RoomId>) -> Result<Unit> = { _, _ -> lambdaError() }
 
-    override suspend fun forwardEvent(eventId: EventId, roomIds: List<RoomId>): Result<Unit> = simulateLongTask {
-        forwardEventLambda(eventId, roomIds)
+    override suspend fun forwardEvents(eventIds: List<EventId>, roomIds: List<RoomId>): Result<Unit> = simulateLongTask {
+        forwardEventsLambda(eventIds, roomIds)
     }
 
     var createPollLambda: (

libraries/roomselect/impl/src/main/kotlin/io/element/android/libraries/roomselect/impl/RoomSelectView.kt

@@ -153,7 +153,7 @@ fun RoomSelectView(
         topBar = {
             TopAppBar(
                 titleStr = when (state.mode) {
-                    RoomSelectMode.Forward -> stringResource(CommonStrings.common_forward_message)
+                    RoomSelectMode.Forward -> stringResource(CommonStrings.common_forward_to)
                     RoomSelectMode.Share -> stringResource(CommonStrings.common_send_to)
                 },
                 navigationIcon = {

tests/konsist/src/test/kotlin/io/element/android/tests/konsist/KonsistClassNameTest.kt

@@ -66,6 +66,7 @@ class KonsistClassNameTest {
                 "EditableAvatarViewUriPreviewParam",
                 "LoginModeViewErrorPreviewParam",
                 "OverlapRatioPreviewParam",
+                "SelectionCountPreviewParam",
                 "TextFileContentPreviewParam",
                 "HtmlMessageContentPreviewParam",
             )

tests/konsist/src/test/kotlin/io/element/android/tests/konsist/KonsistPreviewTest.kt

@@ -110,6 +110,7 @@ class KonsistPreviewTest {
         "MessageComposerViewVoicePreview",
         "MessagesReactionButtonAddPreview",
         "MessagesReactionButtonExtraPreview",
+        "MessagesViewSelectionModePreview",
         "MessagesViewWithIdentityChangePreview",
         "PendingMemberRowWithLongNamePreview",
         "PinUnlockViewInAppPreview",
@@ -133,6 +134,7 @@ class KonsistPreviewTest {
         "SasEmojisPreview",
         "SecureBackupSetupViewChangePreview",
         "SelectedUserCannotRemovePreview",
+        "SelectionIndicatorSelectedPreview",
         "SpaceMembersViewNoHeroesPreview",
         "SyncStateViewServerUnreachablePreview",
         "TextComposerAddCaptionPreview",
@@ -179,6 +181,7 @@ class KonsistPreviewTest {
         "TimelineItemVoiceViewScanningContentPreview",
         "TimelineItemVoiceViewUnifiedPreview",
         "TimelineViewMessageShieldPreview",
+        "TimelineViewSelectionModePreview",
         "TimelineViewWithReadMarkerBothIndicatorsPreview",
         "TimelineViewWithReadMarkerJumpToUnreadIndicatorOnlyPreview",
         "UserAvatarColorsPreview",