Merge pull request #139 from vector-im/feature/undo_reaction

Undo Reaction

matrix-sdk-android/src/androidTest/java/im/vector/matrix/android/session/room/timeline/TimelineTest.kt

@@ -18,10 +18,12 @@ package im.vector.matrix.android.session.room.timeline
 
 import com.zhuinden.monarchy.Monarchy
 import im.vector.matrix.android.InstrumentedTest
+import im.vector.matrix.android.api.auth.data.Credentials
 import im.vector.matrix.android.api.session.room.timeline.Timeline
 import im.vector.matrix.android.api.session.room.timeline.TimelineEvent
 import im.vector.matrix.android.internal.session.room.EventRelationExtractor
-import im.vector.matrix.android.internal.session.room.membership.SenderRoomMemberExtractor
+import im.vector.matrix.android.internal.session.room.EventRelationsAggregationUpdater
+import im.vector.matrix.android.internal.session.room.members.SenderRoomMemberExtractor
 import im.vector.matrix.android.internal.session.room.timeline.DefaultTimeline
 import im.vector.matrix.android.internal.session.room.timeline.TimelineEventFactory
 import im.vector.matrix.android.internal.session.room.timeline.TokenChunkEventPersistor
@@ -55,7 +57,8 @@ internal class TimelineTest : InstrumentedTest {
 
     private fun createTimeline(initialEventId: String? = null): Timeline {
         val taskExecutor = TaskExecutor(testCoroutineDispatchers)
-        val tokenChunkEventPersistor = TokenChunkEventPersistor(monarchy)
+        val erau = EventRelationsAggregationUpdater(Credentials("", "", "", null, null))
+        val tokenChunkEventPersistor = TokenChunkEventPersistor(monarchy, erau)
         val paginationTask = FakePaginationTask(tokenChunkEventPersistor)
         val getContextOfEventTask = FakeGetContextOfEventTask(tokenChunkEventPersistor)
         val roomMemberExtractor = SenderRoomMemberExtractor(ROOM_ID)

matrix-sdk-android/src/main/java/im/vector/matrix/android/api/session/events/model/UnsignedData.kt

@@ -25,5 +25,5 @@ data class UnsignedData(
         @Json(name = "redacted_because") val redactedEvent: Event? = null,
         @Json(name = "transaction_id") val transactionId: String? = null,
         @Json(name = "prev_content") val prevContent: Map<String, Any>? = null,
-        @Json(name = "m.relations") val relations: AggregatedRelations?
+        @Json(name = "m.relations") val relations: AggregatedRelations? = null
 )

matrix-sdk-android/src/main/java/im/vector/matrix/android/api/session/room/Room.kt

@@ -19,6 +19,7 @@ package im.vector.matrix.android.api.session.room
 import androidx.lifecycle.LiveData
 import im.vector.matrix.android.api.session.room.members.MembershipService
 import im.vector.matrix.android.api.session.room.model.RoomSummary
+import im.vector.matrix.android.api.session.room.model.annotation.ReactionService
 import im.vector.matrix.android.api.session.room.read.ReadService
 import im.vector.matrix.android.api.session.room.send.SendService
 import im.vector.matrix.android.api.session.room.state.StateService
@@ -27,7 +28,7 @@ import im.vector.matrix.android.api.session.room.timeline.TimelineService
 /**
  * This interface defines methods to interact within a room.
  */
-interface Room : TimelineService, SendService, ReadService, MembershipService, StateService {
+interface Room : TimelineService, SendService, ReadService, MembershipService, StateService , ReactionService{
 
     /**
      * The roomId of this room

matrix-sdk-android/src/main/java/im/vector/matrix/android/api/session/room/model/annotation/ReactionService.kt

@@ -0,0 +1,52 @@
+/*
+ * Copyright 2019 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package im.vector.matrix.android.api.session.room.model.annotation
+
+import im.vector.matrix.android.api.util.Cancelable
+
+interface ReactionService {
+
+
+    /**
+     * Sends a reaction (emoji) to the targetedEvent.
+     * @param reaction the reaction (preferably emoji)
+     * @param targetEventId the id of the event being reacted
+     */
+    fun sendReaction(reaction: String, targetEventId: String): Cancelable
+
+
+    /**
+     * Undo a reaction (emoji) to the targetedEvent.
+     * @param reaction the reaction (preferably emoji)
+     * @param targetEventId the id of the event being reacted
+     * @param myUserId used to know if a reaction event was made by the user
+     */
+    fun undoReaction(reaction: String, targetEventId: String, myUserId: String)//: Cancelable
+
+
+    /**
+     * Update a quick reaction (toggle).
+     * If you have reacted with agree and then you click on disagree, this call will delete(redact)
+     * the disagree and add the agree
+     * If you click on a reaction that you already reacted with, it will undo it
+     * @param reaction the reaction (preferably emoji)
+     * @param oppositeReaction the opposite reaction(preferably emoji)
+     * @param targetEventId the id of the event being reacted
+     * @param myUserId used to know if a reaction event was made by the user
+     */
+    fun updateQuickReaction(reaction: String, oppositeReaction: String, targetEventId: String, myUserId: String)
+
+}

matrix-sdk-android/src/main/java/im/vector/matrix/android/api/session/room/send/SendService.kt

@@ -17,6 +17,7 @@
 package im.vector.matrix.android.api.session.room.send
 
 import im.vector.matrix.android.api.session.content.ContentAttachmentData
+import im.vector.matrix.android.api.session.events.model.Event
 import im.vector.matrix.android.api.session.room.model.message.MessageType
 import im.vector.matrix.android.api.util.Cancelable
 
@@ -48,7 +49,6 @@ interface SendService {
      */
     fun sendMedias(attachments: List<ContentAttachmentData>): Cancelable
 
-
+    fun redactEvent(event: Event, reason: String?): Cancelable
-    fun sendReaction(reaction: String, targetEventId: String) : Cancelable
 
 }

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/SessionModule.kt

@@ -154,7 +154,7 @@ internal class SessionModule(private val sessionParams: SessionParams) {
 
         scope(DefaultSession.SCOPE) {
             val groupSummaryUpdater = GroupSummaryUpdater(get())
-            val eventsPruner = EventsPruner(get())
+            val eventsPruner = EventsPruner(get(), get(), get(), get())
             val userEntityUpdater = UserEntityUpdater(get(), get(), get())
             listOf<LiveEntityObserver>(groupSummaryUpdater, eventsPruner, userEntityUpdater)
         }

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/DefaultRoom.kt

@@ -22,6 +22,7 @@ import com.zhuinden.monarchy.Monarchy
 import im.vector.matrix.android.api.session.room.Room
 import im.vector.matrix.android.api.session.room.members.MembershipService
 import im.vector.matrix.android.api.session.room.model.RoomSummary
+import im.vector.matrix.android.api.session.room.model.annotation.ReactionService
 import im.vector.matrix.android.api.session.room.read.ReadService
 import im.vector.matrix.android.api.session.room.send.SendService
 import im.vector.matrix.android.api.session.room.state.StateService
@@ -39,12 +40,14 @@ internal class DefaultRoom(
         private val sendService: SendService,
         private val stateService: StateService,
         private val readService: ReadService,
+        private val reactionService: ReactionService,
         private val roomMembersService: MembershipService
 ) : Room,
         TimelineService by timelineService,
         SendService by sendService,
         StateService by stateService,
         ReadService by readService,
+        ReactionService by reactionService,
     MembershipService by roomMembersService {
 
     override val roomSummary: LiveData<RoomSummary> by lazy {

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/EventRelationsAggregationUpdater.kt

@@ -67,13 +67,14 @@ internal class EventRelationsAggregationUpdater(private val credentials: Credent
                     sum.key = reaction
                     sum.firstTimestamp = event.originServerTs ?: 0
                     sum.count = 1
+                    sum.sourceEvents.add(event.eventId)
                     sum.addedByMe = sum.addedByMe || (credentials.userId == event.sender)
                     eventSummary.reactionsSummary.add(sum)
                 } else {
                     //is this a known event (is possible? pagination?)
                     if (!sum.sourceEvents.contains(eventId)) {
                         sum.count += 1
-                        sum.sourceEvents.add(eventId)
+                        sum.sourceEvents.add(event.eventId)
                         sum.addedByMe = sum.addedByMe || (credentials.userId == event.sender)
                     }
                 }

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/RoomAPI.kt

@@ -197,4 +197,22 @@ internal interface RoomAPI {
     @POST(NetworkConstants.URI_API_PREFIX_PATH_R0 + "rooms/{roomId}/leave")
     fun leave(@Path("roomId") roomId: String,
               @Body params: Map<String, String>): Call<Unit>
+
+    /**
+     * Strips all information out of an event which isn't critical to the integrity of the server-side representation of the room.
+     * This cannot be undone.
+     * Users may redact their own events, and any user with a power level greater than or equal to the redact power level of the room may redact events there.
+     *
+     * @param txId      the transaction Id
+     * @param roomId    the room id
+     * @param eventId   the event to delete
+     * @param reason   json containing reason key {"reason": "Indecent material"}
+     */
+    @PUT(NetworkConstants.URI_API_PREFIX_PATH_R0 + "rooms/{roomId}/redact/{eventId}/{txnId}")
+    fun redactEvent(
+            @Path("txnId") txId: String,
+            @Path("roomId") roomId: String,
+            @Path("eventId") parent_id: String,
+            @Body reason:  Map<String, String>
+    ): Call<SendResponse>
 }

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/RoomFactory.kt

@@ -19,6 +19,9 @@ package im.vector.matrix.android.internal.session.room
 import com.zhuinden.monarchy.Monarchy
 import im.vector.matrix.android.api.session.room.Room
 import im.vector.matrix.android.internal.session.room.membership.DefaultMembershipService
+import im.vector.matrix.android.internal.session.room.annotation.FindReactionEventForUndoTask
+import im.vector.matrix.android.internal.session.room.annotation.DefaultReactionService
+import im.vector.matrix.android.internal.session.room.annotation.UpdateQuickReactionTask
 import im.vector.matrix.android.internal.session.room.membership.LoadRoomMembersTask
 import im.vector.matrix.android.internal.session.room.membership.SenderRoomMemberExtractor
 import im.vector.matrix.android.internal.session.room.membership.joining.InviteTask
@@ -45,6 +48,8 @@ internal class RoomFactory(private val monarchy: Monarchy,
                            private val paginationTask: PaginationTask,
                            private val contextOfEventTask: GetContextOfEventTask,
                            private val setReadMarkersTask: SetReadMarkersTask,
+                           private val findReactionEventForUndoTask: FindReactionEventForUndoTask,
+                           private val updateQuickReactionTask: UpdateQuickReactionTask,
                            private val joinRoomTask: JoinRoomTask,
                            private val leaveRoomTask: LeaveRoomTask) {
 
@@ -53,6 +58,7 @@ internal class RoomFactory(private val monarchy: Monarchy,
         val timelineEventFactory = TimelineEventFactory(roomMemberExtractor, EventRelationExtractor())
         val timelineService = DefaultTimelineService(roomId, monarchy, taskExecutor, timelineEventFactory, contextOfEventTask, paginationTask)
         val sendService = DefaultSendService(roomId, eventFactory, monarchy)
+        val reactionService = DefaultReactionService(roomId, eventFactory, findReactionEventForUndoTask, updateQuickReactionTask, taskExecutor)
         val stateService = DefaultStateService(roomId, taskExecutor, sendStateTask)
         val roomMembersService = DefaultMembershipService(roomId, monarchy, taskExecutor, loadRoomMembersTask, inviteTask, joinRoomTask, leaveRoomTask)
         val readService = DefaultReadService(roomId, monarchy, taskExecutor, setReadMarkersTask)
@@ -64,6 +70,7 @@ internal class RoomFactory(private val monarchy: Monarchy,
                 sendService,
                 stateService,
                 readService,
+                reactionService,
                 roomMembersService
         )
     }

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/RoomModule.kt

@@ -17,6 +17,10 @@
 package im.vector.matrix.android.internal.session.room
 
 import im.vector.matrix.android.internal.session.DefaultSession
+import im.vector.matrix.android.internal.session.room.annotation.DefaultFindReactionEventForUndoTask
+import im.vector.matrix.android.internal.session.room.annotation.DefaultUpdateQuickReactionTask
+import im.vector.matrix.android.internal.session.room.annotation.FindReactionEventForUndoTask
+import im.vector.matrix.android.internal.session.room.annotation.UpdateQuickReactionTask
 import im.vector.matrix.android.internal.session.room.create.CreateRoomTask
 import im.vector.matrix.android.internal.session.room.create.DefaultCreateRoomTask
 import im.vector.matrix.android.internal.session.room.membership.DefaultLoadRoomMembersTask
@@ -27,16 +31,14 @@ import im.vector.matrix.android.internal.session.room.membership.joining.InviteT
 import im.vector.matrix.android.internal.session.room.membership.joining.JoinRoomTask
 import im.vector.matrix.android.internal.session.room.membership.leaving.DefaultLeaveRoomTask
 import im.vector.matrix.android.internal.session.room.membership.leaving.LeaveRoomTask
+import im.vector.matrix.android.internal.session.room.prune.DefaultPruneEventTask
+import im.vector.matrix.android.internal.session.room.prune.PruneEventTask
 import im.vector.matrix.android.internal.session.room.read.DefaultSetReadMarkersTask
 import im.vector.matrix.android.internal.session.room.read.SetReadMarkersTask
 import im.vector.matrix.android.internal.session.room.send.LocalEchoEventFactory
 import im.vector.matrix.android.internal.session.room.state.DefaultSendStateTask
 import im.vector.matrix.android.internal.session.room.state.SendStateTask
-import im.vector.matrix.android.internal.session.room.timeline.DefaultGetContextOfEventTask
+import im.vector.matrix.android.internal.session.room.timeline.*
-import im.vector.matrix.android.internal.session.room.timeline.DefaultPaginationTask
-import im.vector.matrix.android.internal.session.room.timeline.GetContextOfEventTask
-import im.vector.matrix.android.internal.session.room.timeline.PaginationTask
-import im.vector.matrix.android.internal.session.room.timeline.TokenChunkEventPersistor
 import org.koin.dsl.module.module
 import retrofit2.Retrofit
 
@@ -75,7 +77,7 @@ class RoomModule {
         }
 
         scope(DefaultSession.SCOPE) {
-            RoomFactory(get(), get(), get(), get(), get(), get(), get(), get(), get(), get(), get())
+            RoomFactory(get(), get(), get(), get(), get(), get(), get(), get(), get(), get(), get(), get(), get())
         }
 
         scope(DefaultSession.SCOPE) {
@@ -98,5 +100,17 @@ class RoomModule {
             DefaultSendStateTask(get()) as SendStateTask
         }
 
+        scope(DefaultSession.SCOPE) {
+            DefaultFindReactionEventForUndoTask(get()) as FindReactionEventForUndoTask
+        }
+
+        scope(DefaultSession.SCOPE) {
+            DefaultUpdateQuickReactionTask(get()) as UpdateQuickReactionTask
+        }
+
+        scope(DefaultSession.SCOPE) {
+            DefaultPruneEventTask(get()) as PruneEventTask
+        }
+
     }
 }

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/annotation/DefaultReactionService.kt

@@ -0,0 +1,153 @@
+/*
+ * Copyright 2019 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package im.vector.matrix.android.internal.session.room.annotation
+
+import androidx.work.*
+import im.vector.matrix.android.api.MatrixCallback
+import im.vector.matrix.android.api.session.events.model.Event
+import im.vector.matrix.android.api.session.room.model.annotation.ReactionService
+import im.vector.matrix.android.api.util.Cancelable
+import im.vector.matrix.android.internal.session.room.send.LocalEchoEventFactory
+import im.vector.matrix.android.internal.session.room.send.RedactEventWorker
+import im.vector.matrix.android.internal.session.room.send.SendEventWorker
+import im.vector.matrix.android.internal.task.TaskExecutor
+import im.vector.matrix.android.internal.task.configureWith
+import im.vector.matrix.android.internal.util.CancelableWork
+import im.vector.matrix.android.internal.util.WorkerParamsFactory
+import java.util.concurrent.TimeUnit
+
+private const val REACTION_WORK = "REACTION_WORK"
+private const val BACKOFF_DELAY = 10_000L
+
+private val WORK_CONSTRAINTS = Constraints.Builder()
+        .setRequiredNetworkType(NetworkType.CONNECTED)
+        .build()
+
+internal class DefaultReactionService(private val roomId: String,
+                                      private val eventFactory: LocalEchoEventFactory,
+                                      private val findReactionEventForUndoTask: FindReactionEventForUndoTask,
+                                      private val updateQuickReactionTask: UpdateQuickReactionTask,
+                                      private val taskExecutor: TaskExecutor)
+    : ReactionService {
+
+
+    override fun sendReaction(reaction: String, targetEventId: String): Cancelable {
+        val event = eventFactory.createReactionEvent(roomId, targetEventId, reaction)
+//                .also {
+//            //saveLocalEcho(it)
+//        }
+        val sendRelationWork = createSendRelationWork(event)
+        WorkManager.getInstance()
+                .beginUniqueWork(buildWorkIdentifier(REACTION_WORK), ExistingWorkPolicy.APPEND, sendRelationWork)
+                .enqueue()
+        return CancelableWork(sendRelationWork.id)
+    }
+
+
+    private fun createSendRelationWork(event: Event): OneTimeWorkRequest {
+        //TODO use the new API to send relation (for now use regular send)
+        val sendContentWorkerParams = SendEventWorker.Params(
+                roomId, event)
+        val sendWorkData = WorkerParamsFactory.toData(sendContentWorkerParams)
+
+        return OneTimeWorkRequestBuilder<SendEventWorker>()
+                .setConstraints(WORK_CONSTRAINTS)
+                .setInputData(sendWorkData)
+                .setBackoffCriteria(BackoffPolicy.LINEAR, BACKOFF_DELAY, TimeUnit.MILLISECONDS)
+                .build()
+    }
+
+    override fun undoReaction(reaction: String, targetEventId: String, myUserId: String)/*: Cancelable*/ {
+
+        val params = FindReactionEventForUndoTask.Params(
+                roomId,
+                targetEventId,
+                reaction,
+                myUserId
+        )
+        findReactionEventForUndoTask.configureWith(params)
+                .enableRetry()
+                .dispatchTo(object : MatrixCallback<FindReactionEventForUndoTask.Result> {
+                    override fun onSuccess(data: FindReactionEventForUndoTask.Result) {
+                        data.redactEventId?.let { toRedact ->
+                            val redactWork = createRedactEventWork(toRedact, null)
+                            WorkManager.getInstance()
+                                    .beginUniqueWork(buildWorkIdentifier(REACTION_WORK), ExistingWorkPolicy.APPEND, redactWork)
+                                    .enqueue()
+                        }
+                    }
+                })
+                .executeBy(taskExecutor)
+
+    }
+
+
+    override fun updateQuickReaction(reaction: String, oppositeReaction: String, targetEventId: String, myUserId: String) {
+
+        val params = UpdateQuickReactionTask.Params(
+                roomId,
+                targetEventId,
+                reaction,
+                oppositeReaction,
+                myUserId
+        )
+
+        updateQuickReactionTask.configureWith(params)
+                .dispatchTo(object : MatrixCallback<UpdateQuickReactionTask.Result> {
+                    override fun onSuccess(data: UpdateQuickReactionTask.Result) {
+                        data.reactionToAdd?.also { sendReaction(it, targetEventId) }
+                        data.reactionToRedact.forEach {
+                            val redactWork = createRedactEventWork(it, null)
+                            WorkManager.getInstance()
+                                    .beginUniqueWork(buildWorkIdentifier(REACTION_WORK), ExistingWorkPolicy.APPEND, redactWork)
+                                    .enqueue()
+                        }
+                    }
+                })
+                .executeBy(taskExecutor)
+    }
+
+    private fun buildWorkIdentifier(identifier: String): String {
+        return "${roomId}_$identifier"
+    }
+
+//    private fun saveLocalEcho(event: Event) {
+//        monarchy.tryTransactionAsync { realm ->
+//            val roomEntity = RoomEntity.where(realm, roomId = roomId).findFirst()
+//                    ?: return@tryTransactionAsync
+//            val liveChunk = ChunkEntity.findLastLiveChunkFromRoom(realm, roomId = roomId)
+//                    ?: return@tryTransactionAsync
+//
+//            roomEntity.addSendingEvent(event, liveChunk.forwardsStateIndex ?: 0)
+//        }
+//    }
+
+    //TODO duplicate with send service?
+    private fun createRedactEventWork(eventId: String, reason: String?): OneTimeWorkRequest {
+
+        //TODO create local echo of m.room.redaction event?
+
+        val sendContentWorkerParams = RedactEventWorker.Params(
+                roomId, eventId, reason)
+        val redactWorkData = WorkerParamsFactory.toData(sendContentWorkerParams)
+
+        return OneTimeWorkRequestBuilder<RedactEventWorker>()
+                .setConstraints(WORK_CONSTRAINTS)
+                .setInputData(redactWorkData)
+                .setBackoffCriteria(BackoffPolicy.LINEAR, BACKOFF_DELAY, TimeUnit.MILLISECONDS)
+                .build()
+    }
+}

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/annotation/FindReactionEventForUndoTask.kt

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2019 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package im.vector.matrix.android.internal.session.room.annotation
+
+import arrow.core.Try
+import com.zhuinden.monarchy.Monarchy
+import im.vector.matrix.android.internal.database.model.EventAnnotationsSummaryEntity
+import im.vector.matrix.android.internal.database.model.EventEntity
+import im.vector.matrix.android.internal.database.model.ReactionAggregatedSummaryEntityFields
+import im.vector.matrix.android.internal.database.query.where
+import im.vector.matrix.android.internal.task.Task
+import io.realm.Realm
+
+
+internal interface FindReactionEventForUndoTask : Task<FindReactionEventForUndoTask.Params, FindReactionEventForUndoTask.Result> {
+
+    data class Params(
+            val roomId: String,
+            val eventId: String,
+            val reaction: String,
+            val myUserId: String
+    )
+
+    data class Result(
+            val redactEventId: String?
+    )
+
+}
+
+internal class DefaultFindReactionEventForUndoTask(private val monarchy: Monarchy) : FindReactionEventForUndoTask {
+
+    override fun execute(params: FindReactionEventForUndoTask.Params): Try<FindReactionEventForUndoTask.Result> {
+        return Try {
+            var eventId: String? = null
+            monarchy.doWithRealm { realm ->
+                eventId = getReactionToRedact(realm, params.reaction, params.eventId, params.myUserId)?.eventId
+            }
+            FindReactionEventForUndoTask.Result(eventId)
+        }
+    }
+
+    private fun getReactionToRedact(realm: Realm, reaction: String, eventId: String, userId: String): EventEntity? {
+        val summary = EventAnnotationsSummaryEntity.where(realm, eventId).findFirst()
+        if (summary != null) {
+            summary.reactionsSummary.where()
+                    .equalTo(ReactionAggregatedSummaryEntityFields.KEY, reaction)
+                    .findFirst()?.let {
+                        //want to find the event orignated by me!
+                        it.sourceEvents.forEach {
+                            //find source event
+                            EventEntity.where(realm, it).findFirst()?.let { eventEntity ->
+                                //is it mine?
+                                if (eventEntity.sender == userId) {
+                                    return eventEntity
+                                }
+                            }
+                        }
+                    }
+        }
+        return null
+    }
+}

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/annotation/SendRelationWorker.kt

@@ -1,9 +1,25 @@
-package im.vector.matrix.android.internal.session.room.send
+/*
+ * Copyright 2019 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package im.vector.matrix.android.internal.session.room.annotation
 
 import android.content.Context
 import androidx.work.Worker
 import androidx.work.WorkerParameters
 import com.squareup.moshi.JsonClass
+import im.vector.matrix.android.api.failure.Failure
 import im.vector.matrix.android.api.session.events.model.Event
 import im.vector.matrix.android.api.session.events.model.toModel
 import im.vector.matrix.android.api.session.room.model.annotation.ReactionContent
@@ -11,6 +27,7 @@ import im.vector.matrix.android.api.session.room.model.annotation.ReactionInfo
 import im.vector.matrix.android.internal.di.MatrixKoinComponent
 import im.vector.matrix.android.internal.network.executeRequest
 import im.vector.matrix.android.internal.session.room.RoomAPI
+import im.vector.matrix.android.internal.session.room.send.SendResponse
 import im.vector.matrix.android.internal.util.WorkerParamsFactory
 import org.koin.standalone.inject
 
@@ -28,7 +45,7 @@ class SendRelationWorker(context: Context, params: WorkerParameters)
     private val roomAPI by inject<RoomAPI>()
 
     override fun doWork(): Result {
-        val params = WorkerParamsFactory.fromData<SendRelationWorker.Params>(inputData)
+        val params = WorkerParamsFactory.fromData<Params>(inputData)
                 ?: return Result.failure()
 
         val localEvent = params.event
@@ -50,6 +67,11 @@ class SendRelationWorker(context: Context, params: WorkerParameters)
                     content = localEvent.content
             )
         }
-        return result.fold({ Result.retry() }, { Result.success() })
+        return result.fold({
+            when (it) {
+                is Failure.NetworkConnection -> Result.retry()
+                else -> Result.failure()
+            }
+        }, { Result.success() })
     }
 }

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/annotation/UpdateQuickReactionTask.kt

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2019 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package im.vector.matrix.android.internal.session.room.annotation
+
+import arrow.core.Try
+import com.zhuinden.monarchy.Monarchy
+import im.vector.matrix.android.internal.database.model.EventAnnotationsSummaryEntity
+import im.vector.matrix.android.internal.database.model.EventEntity
+import im.vector.matrix.android.internal.database.model.ReactionAggregatedSummaryEntityFields
+import im.vector.matrix.android.internal.database.query.where
+import im.vector.matrix.android.internal.task.Task
+import io.realm.Realm
+
+
+internal interface UpdateQuickReactionTask : Task<UpdateQuickReactionTask.Params, UpdateQuickReactionTask.Result> {
+
+    data class Params(
+            val roomId: String,
+            val eventId: String,
+            val reaction: String,
+            val oppositeReaction: String,
+            val myUserId: String
+    )
+
+    data class Result(
+            val reactionToAdd: String?,
+            val reactionToRedact: List<String>
+    )
+}
+
+internal class DefaultUpdateQuickReactionTask(private val monarchy: Monarchy) : UpdateQuickReactionTask {
+    override fun execute(params: UpdateQuickReactionTask.Params): Try<UpdateQuickReactionTask.Result> {
+        return Try {
+            var res: Pair<String?, List<String>?>? = null
+            monarchy.doWithRealm { realm ->
+                res = updateQuickReaction(realm, params.reaction, params.oppositeReaction, params.eventId, params.myUserId)
+            }
+            UpdateQuickReactionTask.Result(res?.first, res?.second ?: emptyList())
+        }
+    }
+
+
+    private fun updateQuickReaction(realm: Realm, reaction: String, oppositeReaction: String, eventId: String, myUserId: String): Pair<String?, List<String>?> {
+        //the emoji reaction has been selected, we need to check if we have reacted it or not
+        val existingSummary = EventAnnotationsSummaryEntity.where(realm, eventId).findFirst()
+                ?: return Pair(reaction, null)
+
+        //Ok there is already reactions on this event, have we reacted to it
+        val aggregationForReaction = existingSummary.reactionsSummary.where()
+                .equalTo(ReactionAggregatedSummaryEntityFields.KEY, reaction)
+                .findFirst()
+        val aggregationForOppositeReaction = existingSummary.reactionsSummary.where()
+                .equalTo(ReactionAggregatedSummaryEntityFields.KEY, oppositeReaction)
+                .findFirst()
+
+        if (aggregationForReaction == null || !aggregationForReaction.addedByMe) {
+            //i haven't yet reacted to it, so need to add it, but do I need to redact the opposite?
+            val toRedact = aggregationForOppositeReaction?.sourceEvents?.mapNotNull {
+                //find source event
+                val entity = EventEntity.where(realm, it).findFirst()
+                if (entity?.sender == myUserId) entity.eventId else null
+            }
+            return Pair(reaction, toRedact)
+        } else {
+            //I already added it, so i need to undo it (like a toggle)
+            // find all m.redaction coming from me to readact them
+            val toRedact = aggregationForReaction.sourceEvents.mapNotNull {
+                //find source event
+                val entity = EventEntity.where(realm, it).findFirst()
+                if (entity?.sender == myUserId) entity.eventId else null
+            }
+            return Pair(null, toRedact)
+        }
+
+    }
+}

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/prune/EventsPruner.kt

@@ -16,38 +16,37 @@
 
 package im.vector.matrix.android.internal.session.room.prune
 
-import androidx.work.ExistingWorkPolicy
-import androidx.work.OneTimeWorkRequestBuilder
-import androidx.work.WorkManager
 import com.zhuinden.monarchy.Monarchy
+import im.vector.matrix.android.api.auth.data.Credentials
 import im.vector.matrix.android.api.session.events.model.EventType
 import im.vector.matrix.android.internal.database.RealmLiveEntityObserver
 import im.vector.matrix.android.internal.database.mapper.asDomain
 import im.vector.matrix.android.internal.database.model.EventEntity
 import im.vector.matrix.android.internal.database.query.where
-import im.vector.matrix.android.internal.util.WorkerParamsFactory
+import im.vector.matrix.android.internal.task.TaskExecutor
+import im.vector.matrix.android.internal.task.configureWith
 
-private const val PRUNE_EVENT_WORKER = "PRUNE_EVENT_WORKER"
 
-internal class EventsPruner(monarchy: Monarchy) :
+internal class EventsPruner(monarchy: Monarchy,
+                            private val credentials: Credentials,
+                            private val pruneEventTask: PruneEventTask,
+                            private val taskExecutor: TaskExecutor) :
         RealmLiveEntityObserver<EventEntity>(monarchy) {
 
     override val query = Monarchy.Query<EventEntity> { EventEntity.where(it, type = EventType.REDACTION) }
 
     override fun processChanges(inserted: List<EventEntity>, updated: List<EventEntity>, deleted: List<EventEntity>) {
         val redactionEvents = inserted
-                .mapNotNull { it.asDomain().redacts }
+                .mapNotNull { it.asDomain() }
 
-        val pruneEventWorkerParams = PruneEventWorker.Params(redactionEvents)
+        val params = PruneEventTask.Params(
-        val workData = WorkerParamsFactory.toData(pruneEventWorkerParams)
+                redactionEvents,
+                credentials.userId
+        )
 
-        val sendWork = OneTimeWorkRequestBuilder<PruneEventWorker>()
+        pruneEventTask.configureWith(params)
-                .setInputData(workData)
+                .executeBy(taskExecutor)
-                .build()
 
-        WorkManager.getInstance()
-                .beginUniqueWork(PRUNE_EVENT_WORKER, ExistingWorkPolicy.APPEND, sendWork)
-                .enqueue()
     }
 
 }

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/prune/PruneEventTask.kt

@@ -0,0 +1,142 @@
+/*
+ * Copyright 2019 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package im.vector.matrix.android.internal.session.room.prune
+
+import arrow.core.Try
+import com.zhuinden.monarchy.Monarchy
+import im.vector.matrix.android.api.session.events.model.Event
+import im.vector.matrix.android.api.session.events.model.EventType
+import im.vector.matrix.android.api.session.events.model.UnsignedData
+import im.vector.matrix.android.api.session.events.model.toModel
+import im.vector.matrix.android.api.session.room.model.annotation.ReactionContent
+import im.vector.matrix.android.internal.database.mapper.ContentMapper
+import im.vector.matrix.android.internal.database.mapper.EventMapper
+import im.vector.matrix.android.internal.database.model.EventAnnotationsSummaryEntity
+import im.vector.matrix.android.internal.database.model.EventEntity
+import im.vector.matrix.android.internal.database.model.ReactionAggregatedSummaryEntityFields
+import im.vector.matrix.android.internal.database.query.where
+import im.vector.matrix.android.internal.di.MoshiProvider
+import im.vector.matrix.android.internal.task.Task
+import im.vector.matrix.android.internal.util.tryTransactionSync
+import io.realm.Realm
+import timber.log.Timber
+
+
+internal interface PruneEventTask : Task<PruneEventTask.Params, Unit> {
+
+    data class Params(
+            val redactionEvents: List<Event>,
+            val userId: String
+    )
+
+}
+
+internal class DefaultPruneEventTask(private val monarchy: Monarchy) : PruneEventTask {
+
+    override fun execute(params: PruneEventTask.Params): Try<Unit> {
+        return monarchy.tryTransactionSync { realm ->
+            params.redactionEvents.forEach { event ->
+                pruneEvent(realm, event, params.userId)
+            }
+        }
+    }
+
+    private fun pruneEvent(realm: Realm, redactionEvent: Event, userId: String) {
+        if (redactionEvent.redacts.isNullOrBlank()) {
+            return
+        }
+
+        val eventToPrune = EventEntity.where(realm, eventId = redactionEvent.redacts).findFirst()
+                ?: return
+
+        val allowedKeys = computeAllowedKeys(eventToPrune.type)
+        if (allowedKeys.isNotEmpty()) {
+            val prunedContent = ContentMapper.map(eventToPrune.content)?.filterKeys { key -> allowedKeys.contains(key) }
+            eventToPrune.content = ContentMapper.map(prunedContent)
+        } else {
+            when (eventToPrune.type) {
+                EventType.MESSAGE -> {
+                    Timber.d("REDACTION for message ${eventToPrune.eventId}")
+                    val unsignedData = EventMapper.map(eventToPrune).unsignedData
+                            ?: UnsignedData(null, null)
+                    val modified = unsignedData.copy(redactedEvent = redactionEvent)
+                    eventToPrune.content = ContentMapper.map(emptyMap())
+                    eventToPrune.unsignedData = MoshiProvider.providesMoshi().adapter(UnsignedData::class.java).toJson(modified)
+
+                }
+                EventType.REACTION -> {
+                    Timber.d("REDACTION of reaction ${eventToPrune.eventId}")
+                    //delete a reaction, need to update the annotation summary if any
+                    val reactionContent: ReactionContent = EventMapper.map(eventToPrune).content.toModel()
+                            ?: return
+                    val eventThatWasReacted = reactionContent.relatesTo?.eventId ?: return
+
+                    val reactionkey = reactionContent.relatesTo.key
+                    Timber.d("REMOVE reaction for key $reactionkey")
+                    val summary = EventAnnotationsSummaryEntity.where(realm, eventThatWasReacted).findFirst()
+                    if (summary != null) {
+                        summary.reactionsSummary.where()
+                                .equalTo(ReactionAggregatedSummaryEntityFields.KEY, reactionkey)
+                                .findFirst()?.let { summary ->
+                                    Timber.d("Find summary for key with  ${summary.sourceEvents.size} known reactions (count:${summary.count})")
+                                    Timber.d("Known reactions  ${summary.sourceEvents.joinToString(",")}")
+                                    if (summary.sourceEvents.contains(eventToPrune.eventId)) {
+                                        Timber.d("REMOVE reaction for key $reactionkey")
+                                        summary.sourceEvents.remove(eventToPrune.eventId)
+                                        Timber.d("Known reactions after  ${summary.sourceEvents.joinToString(",")}")
+                                        summary.count = summary.count - 1
+                                        if (eventToPrune.sender == userId) {
+                                            //Was it a redact on my reaction?
+                                            summary.addedByMe = false
+                                        }
+                                        if (summary.count == 0) {
+                                            //delete!
+                                            summary.deleteFromRealm()
+                                        }
+                                    } else {
+                                        Timber.e("## Cannot remove summary from count, corresponding reaction ${eventToPrune.eventId} is not known")
+                                    }
+                                }
+                    } else {
+                        Timber.e("## Cannot find summary for key $reactionkey")
+                    }
+                }
+            }
+        }
+    }
+
+    private fun computeAllowedKeys(type: String): List<String> {
+        // Add filtered content, allowed keys in content depends on the event type
+        return when (type) {
+            EventType.STATE_ROOM_MEMBER -> listOf("membership")
+            EventType.STATE_ROOM_CREATE -> listOf("creator")
+            EventType.STATE_ROOM_JOIN_RULES -> listOf("join_rule")
+            EventType.STATE_ROOM_POWER_LEVELS -> listOf("users",
+                    "users_default",
+                    "events",
+                    "events_default",
+                    "state_default",
+                    "ban",
+                    "kick",
+                    "redact",
+                    "invite")
+            EventType.STATE_ROOM_ALIASES -> listOf("aliases")
+            EventType.STATE_CANONICAL_ALIAS -> listOf("alias")
+            EventType.FEEDBACK -> listOf("type", "target_event_id")
+            else -> emptyList()
+        }
+    }
+}

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/prune/PruneEventWorker.kt

@@ -1,94 +0,0 @@
-/*
- * Copyright 2019 New Vector Ltd
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package im.vector.matrix.android.internal.session.room.prune
-
-import android.content.Context
-import androidx.work.Worker
-import androidx.work.WorkerParameters
-import com.squareup.moshi.JsonClass
-import com.zhuinden.monarchy.Monarchy
-import im.vector.matrix.android.api.session.events.model.EventType
-import im.vector.matrix.android.internal.database.mapper.ContentMapper
-import im.vector.matrix.android.internal.database.model.EventEntity
-import im.vector.matrix.android.internal.database.query.where
-import im.vector.matrix.android.internal.di.MatrixKoinComponent
-import im.vector.matrix.android.internal.util.WorkerParamsFactory
-import im.vector.matrix.android.internal.util.tryTransactionSync
-import io.realm.Realm
-import org.koin.standalone.inject
-
-internal class PruneEventWorker(context: Context,
-                                workerParameters: WorkerParameters
-) : Worker(context, workerParameters), MatrixKoinComponent {
-
-    @JsonClass(generateAdapter = true)
-    internal class Params(
-            val eventIdsToRedact: List<String>
-    )
-
-    private val monarchy by inject<Monarchy>()
-
-    override fun doWork(): Result {
-        val params = WorkerParamsFactory.fromData<Params>(inputData)
-                     ?: return Result.failure()
-
-        val result = monarchy.tryTransactionSync { realm ->
-            params.eventIdsToRedact.forEach { eventId ->
-                pruneEvent(realm, eventId)
-            }
-        }
-        return result.fold({ Result.retry() }, { Result.success() })
-    }
-
-    private fun pruneEvent(realm: Realm, eventIdToRedact: String) {
-        if (eventIdToRedact.isEmpty()) {
-            return
-        }
-
-        val eventToPrune = EventEntity.where(realm, eventId = eventIdToRedact).findFirst()
-                           ?: return
-
-        val allowedKeys = computeAllowedKeys(eventToPrune.type)
-        if (allowedKeys.isNotEmpty()) {
-            val prunedContent = ContentMapper.map(eventToPrune.content)?.filterKeys { key -> allowedKeys.contains(key) }
-            eventToPrune.content = ContentMapper.map(prunedContent)
-        }
-    }
-
-    private fun computeAllowedKeys(type: String): List<String> {
-        // Add filtered content, allowed keys in content depends on the event type
-        return when (type) {
-            EventType.STATE_ROOM_MEMBER       -> listOf("membership")
-            EventType.STATE_ROOM_CREATE       -> listOf("creator")
-            EventType.STATE_ROOM_JOIN_RULES   -> listOf("join_rule")
-            EventType.STATE_ROOM_POWER_LEVELS -> listOf("users",
-                                                        "users_default",
-                                                        "events",
-                                                        "events_default",
-                                                        "state_default",
-                                                        "ban",
-                                                        "kick",
-                                                        "redact",
-                                                        "invite")
-            EventType.STATE_ROOM_ALIASES      -> listOf("aliases")
-            EventType.STATE_CANONICAL_ALIAS   -> listOf("alias")
-            EventType.FEEDBACK                -> listOf("type", "target_event_id")
-            else                              -> emptyList()
-        }
-    }
-
-}

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/send/DefaultSendService.kt

@@ -16,13 +16,7 @@
 
 package im.vector.matrix.android.internal.session.room.send
 
-import androidx.work.BackoffPolicy
+import androidx.work.*
-import androidx.work.Constraints
-import androidx.work.ExistingWorkPolicy
-import androidx.work.NetworkType
-import androidx.work.OneTimeWorkRequest
-import androidx.work.OneTimeWorkRequestBuilder
-import androidx.work.WorkManager
 import com.zhuinden.monarchy.Monarchy
 import im.vector.matrix.android.api.session.content.ContentAttachmentData
 import im.vector.matrix.android.api.session.events.model.Event
@@ -74,16 +68,14 @@ internal class DefaultSendService(private val roomId: String,
         return cancelableBag
     }
 
-
+    override fun redactEvent(event: Event, reason: String?): Cancelable {
-    override fun sendReaction(reaction: String, targetEventId: String) : Cancelable {
+        //TODO manage local echo ?
-        val event = eventFactory.createReactionEvent(roomId,targetEventId,reaction).also {
+        //TODO manage media/attachements?
-            saveLocalEcho(it)
+        val redactWork = createRedactEventWork(event, reason)
-        }
-        val sendRelationWork = createSendRelationWork(event)
         WorkManager.getInstance()
-                .beginUniqueWork(buildWorkIdentifier(SEND_WORK), ExistingWorkPolicy.APPEND, sendRelationWork)
+                .beginUniqueWork(buildWorkIdentifier(SEND_WORK), ExistingWorkPolicy.APPEND, redactWork)
                 .enqueue()
-        return CancelableWork(sendRelationWork.id)
+        return CancelableWork(redactWork.id)
     }
 
     override fun sendMedia(attachment: ContentAttachmentData): Cancelable {
@@ -128,15 +120,17 @@ internal class DefaultSendService(private val roomId: String,
                 .build()
     }
 
-    private fun createSendRelationWork(event: Event): OneTimeWorkRequest {
+    private fun createRedactEventWork(event: Event, reason: String?): OneTimeWorkRequest {
-        //TODO use the new API to send relation (for now use regular send)
-        val sendContentWorkerParams = SendEventWorker.Params(
-                roomId, event)
-        val sendWorkData = WorkerParamsFactory.toData(sendContentWorkerParams)
 
-        return OneTimeWorkRequestBuilder<SendEventWorker>()
+        //TODO create local echo of m.room.redaction event?
+
+        val sendContentWorkerParams = RedactEventWorker.Params(
+                roomId, event.eventId!!, reason)
+        val redactWorkData = WorkerParamsFactory.toData(sendContentWorkerParams)
+
+        return OneTimeWorkRequestBuilder<RedactEventWorker>()
                 .setConstraints(WORK_CONSTRAINTS)
-                .setInputData(sendWorkData)
+                .setInputData(redactWorkData)
                 .setBackoffCriteria(BackoffPolicy.LINEAR, BACKOFF_DELAY, TimeUnit.MILLISECONDS)
                 .build()
     }

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/send/RedactEventWorker.kt

@@ -0,0 +1,69 @@
+/*
+ * Copyright 2019 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package im.vector.matrix.android.internal.session.room.send
+
+import android.content.Context
+import androidx.work.Worker
+import androidx.work.WorkerParameters
+import com.squareup.moshi.JsonClass
+import im.vector.matrix.android.api.failure.Failure
+import im.vector.matrix.android.internal.di.MatrixKoinComponent
+import im.vector.matrix.android.internal.network.executeRequest
+import im.vector.matrix.android.internal.session.room.RoomAPI
+import im.vector.matrix.android.internal.util.WorkerParamsFactory
+import org.koin.standalone.inject
+import java.util.*
+
+internal class RedactEventWorker(context: Context, params: WorkerParameters)
+    : Worker(context, params), MatrixKoinComponent {
+
+    @JsonClass(generateAdapter = true)
+    internal data class Params(
+            val roomId: String,
+            val eventId: String,
+            val reason: String?
+    )
+
+    private val roomAPI by inject<RoomAPI>()
+
+    override fun doWork(): Result {
+        val params = WorkerParamsFactory.fromData<RedactEventWorker.Params>(inputData)
+                ?: return Result.failure()
+
+        if (params.eventId == null) {
+            return Result.failure()
+        }
+        val txID = UUID.randomUUID().toString()
+
+        val result = executeRequest<SendResponse> {
+            apiCall = roomAPI.redactEvent(
+                    txID,
+                    params.roomId,
+                    params.eventId,
+                    if (params.reason == null) emptyMap() else mapOf("reason" to params.reason)
+            )
+        }
+        return result.fold({
+            when (it) {
+                is Failure.NetworkConnection -> Result.retry()
+                else -> Result.failure()
+            }
+        }, {
+            Result.success()
+        })
+    }
+
+}

matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/timeline/DefaultTimeline.kt

@@ -92,7 +92,7 @@ internal class DefaultTimeline(
 
     private lateinit var eventRelations: RealmResults<EventAnnotationsSummaryEntity>
 
-    private val eventsChangeListener = OrderedRealmCollectionChangeListener<RealmResults<EventEntity>> { _, changeSet ->
+    private val eventsChangeListener = OrderedRealmCollectionChangeListener<RealmResults<EventEntity>> { results, changeSet ->
         if (changeSet.state == OrderedCollectionChangeSet.State.INITIAL) {
             handleInitialLoad()
         } else {
@@ -122,8 +122,22 @@ internal class DefaultTimeline(
                     buildTimelineEvents(startDisplayIndex, direction, range.length.toLong())
                     postSnapshot()
                 }
-
             }
+
+            var hasChanged = false
+            changeSet.changes.forEach {index ->
+                val eventEntity = results[index]
+                eventEntity?.eventId?.let { eventId ->
+                    builtEventsIdMap[eventId]?.let { builtIndex ->
+                        //Update the relation of existing event
+                        builtEvents[builtIndex]?.let { te ->
+                            builtEvents[builtIndex] = timelineEventFactory.create(eventEntity)
+                            hasChanged = true
+                        }
+                    }
+                }
+            }
+            if (hasChanged) postSnapshot()
         }
     }
 
@@ -143,18 +157,6 @@ internal class DefaultTimeline(
                 }
             }
         }
-        changeSet.deletions?.forEach {
-            val eventRelations = collection[it]
-            if (eventRelations != null) {
-                builtEventsIdMap[eventRelations.eventId]?.let { builtIndex ->
-                    //Update the relation of existing event
-                    builtEvents[builtIndex]?.let { te ->
-                        builtEvents[builtIndex] = te.copy(annotations = null)
-                        hasChange = true
-                    }
-                }
-            }
-        }
         if (hasChange)
             postSnapshot()
     }

vector/src/main/java/im/vector/riotredesign/features/home/room/detail/RoomDetailActions.kt

@@ -28,7 +28,11 @@ sealed class RoomDetailActions {
     data class EventDisplayed(val event: TimelineEvent) : RoomDetailActions()
     data class LoadMore(val direction: Timeline.Direction) : RoomDetailActions()
     data class SendReaction(val reaction: String, val targetEventId: String) : RoomDetailActions()
+    data class RedactAction(val targetEventId: String, val reason: String? = "") : RoomDetailActions()
+    data class UndoReaction(val targetEventId: String, val key: String, val reason: String? = "") : RoomDetailActions()
+    data class UpdateQuickReactAction(val targetEventId: String,val selectedReaction: String,val opposite: String) : RoomDetailActions()
     object AcceptInvite : RoomDetailActions()
     object RejectInvite : RoomDetailActions()
 
+
 }

vector/src/main/java/im/vector/riotredesign/features/home/room/detail/RoomDetailFragment.kt

@@ -54,11 +54,7 @@ import com.otaliastudios.autocomplete.AutocompleteCallback
 import com.otaliastudios.autocomplete.CharPolicy
 import im.vector.matrix.android.api.session.Session
 import im.vector.matrix.android.api.session.room.model.Membership
-import im.vector.matrix.android.api.session.room.model.message.MessageAudioContent
+import im.vector.matrix.android.api.session.room.model.message.*
-import im.vector.matrix.android.api.session.room.model.message.MessageContent
-import im.vector.matrix.android.api.session.room.model.message.MessageFileContent
-import im.vector.matrix.android.api.session.room.model.message.MessageImageContent
-import im.vector.matrix.android.api.session.room.model.message.MessageVideoContent
 import im.vector.matrix.android.api.session.room.timeline.TimelineEvent
 import im.vector.matrix.android.api.session.user.model.User
 import im.vector.riotredesign.R
@@ -69,15 +65,7 @@ import im.vector.riotredesign.core.extensions.observeEvent
 import im.vector.riotredesign.core.glide.GlideApp
 import im.vector.riotredesign.core.platform.ToolbarConfigurable
 import im.vector.riotredesign.core.platform.VectorBaseFragment
-import im.vector.riotredesign.core.utils.LiveEvent
+import im.vector.riotredesign.core.utils.*
-import im.vector.riotredesign.core.utils.PERMISSIONS_FOR_TAKING_PHOTO
-import im.vector.riotredesign.core.utils.PERMISSION_REQUEST_CODE_LAUNCH_CAMERA
-import im.vector.riotredesign.core.utils.PERMISSION_REQUEST_CODE_LAUNCH_NATIVE_CAMERA
-import im.vector.riotredesign.core.utils.PERMISSION_REQUEST_CODE_LAUNCH_NATIVE_VIDEO_CAMERA
-import im.vector.riotredesign.core.utils.checkPermissions
-import im.vector.riotredesign.core.utils.copyToClipboard
-import im.vector.riotredesign.core.utils.openCamera
-import im.vector.riotredesign.core.utils.shareMedia
 import im.vector.riotredesign.features.autocomplete.command.AutocompleteCommandPresenter
 import im.vector.riotredesign.features.autocomplete.command.CommandAutocompletePolicy
 import im.vector.riotredesign.features.autocomplete.user.AutocompleteUserPresenter
@@ -521,7 +509,8 @@ class RoomDetailFragment :
             //we should test the current real state of reaction on this event
             roomDetailViewModel.process(RoomDetailActions.SendReaction(reaction, informationData.eventId))
         } else {
-            //TODO it's an undo :/
+            //I need to redact a reaction
+            roomDetailViewModel.process(RoomDetailActions.UndoReaction(informationData.eventId, reaction))
         }
     }
 
@@ -546,6 +535,10 @@ class RoomDetailFragment :
                     snack.view.setBackgroundColor(ContextCompat.getColor(requireContext(), R.color.notification_accent_color))
                     snack.show()
                 }
+                MessageMenuViewModel.ACTION_DELETE -> {
+                    val eventId = actionData.data?.toString() ?: return
+                    roomDetailViewModel.process(RoomDetailActions.RedactAction(eventId, context?.getString(R.string.event_redacted_by_user_reason)))
+                }
                 MessageMenuViewModel.ACTION_SHARE -> {
                     //TODO current data communication is too limited
                     //Need to now the media type
@@ -590,8 +583,9 @@ class RoomDetailFragment :
                             .show()
                 }
                 MessageMenuViewModel.ACTION_QUICK_REACT -> {
-                    (actionData.data as? Pair<String, String>)?.let { pairData ->
+                    //eventId,ClickedOn,Opposite
-                        roomDetailViewModel.process(RoomDetailActions.SendReaction(pairData.second, pairData.first))
+                    (actionData.data as? Triple<String, String, String>)?.let { (eventId, clickedOn, opposite) ->
+                        roomDetailViewModel.process(RoomDetailActions.UpdateQuickReactAction(eventId, clickedOn, opposite))
                     }
                 }
                 else -> {

vector/src/main/java/im/vector/riotredesign/features/home/room/detail/RoomDetailViewModel.kt

@@ -80,9 +80,13 @@ class RoomDetailViewModel(initialState: RoomDetailViewState,
             is RoomDetailActions.SendReaction -> handleSendReaction(action)
             is RoomDetailActions.AcceptInvite -> handleAcceptInvite()
             is RoomDetailActions.RejectInvite -> handleRejectInvite()
+            is RoomDetailActions.RedactAction -> handleRedactEvent(action)
+            is RoomDetailActions.UndoReaction -> handleUndoReact(action)
+            is RoomDetailActions.UpdateQuickReactAction -> handleUpdateQuickReaction(action)
         }
     }
 
+
     private val _sendMessageResultLiveData = MutableLiveData<LiveEvent<SendMessageResult>>()
     val sendMessageResultLiveData: LiveData<LiveEvent<SendMessageResult>>
         get() = _sendMessageResultLiveData
@@ -190,6 +194,21 @@ class RoomDetailViewModel(initialState: RoomDetailViewState,
         room.sendReaction(action.reaction, action.targetEventId)
     }
 
+    private fun handleRedactEvent(action: RoomDetailActions.RedactAction) {
+        val event = room.getTimeLineEvent(action.targetEventId) ?: return
+        room.redactEvent(event.root, action.reason)
+    }
+
+    private fun handleUndoReact(action: RoomDetailActions.UndoReaction) {
+        room.undoReaction(action.key, action.targetEventId, session.sessionParams.credentials.userId)
+    }
+
+
+    private fun handleUpdateQuickReaction(action: RoomDetailActions.UpdateQuickReactAction) {
+        room.updateQuickReaction(action.selectedReaction, action.opposite, action.targetEventId, session.sessionParams.credentials.userId)
+    }
+
+
     private fun handleSendMedia(action: RoomDetailActions.SendMedia) {
         val attachments = action.mediaFiles.map {
             ContentAttachmentData(
@@ -227,6 +246,7 @@ class RoomDetailViewModel(initialState: RoomDetailViewState,
         room.join(object : MatrixCallback<Unit> {})
     }
 
+
     private fun observeEventDisplayedActions() {
         // We are buffering scroll events for one second
         // and keep the most recent one to set the read receipt on.

vector/src/main/java/im/vector/riotredesign/features/home/room/detail/timeline/action/MessageActionsBottomSheet.kt

@@ -95,13 +95,8 @@ class MessageActionsBottomSheet : BaseMvRxBottomSheetDialog() {
                     .commit()
         }
         quickReactionFragment.interactionListener = object : QuickReactionFragment.InteractionListener {
-            override fun didQuickReactWith(clikedOn: String, reactions: List<String>, eventId: String) {
+            override fun didQuickReactWith(clikedOn: String, opposite: String, reactions: List<String>, eventId: String) {
-                if (reactions.contains(clikedOn)) {
+                actionHandlerModel.fireAction(MessageMenuViewModel.ACTION_QUICK_REACT, Triple(eventId, clikedOn, opposite))
-                    //it's an add
-                    actionHandlerModel.fireAction(MessageMenuViewModel.ACTION_QUICK_REACT, Pair(eventId,clikedOn))
-                } else {
-                    //it's a remove
-                }
                 dismiss()
             }
         }

vector/src/main/java/im/vector/riotredesign/features/home/room/detail/timeline/action/MessageMenuViewModel.kt

@@ -73,6 +73,10 @@ class MessageMenuViewModel(initialState: MessageMenuState) : VectorViewModel<Mes
                     this.add(SimpleAction(ACTION_COPY, R.string.copy, R.drawable.ic_copy, messageContent.body))
                 }
 
+                if (canRedact(event, currentSession.sessionParams.credentials.userId)) {
+                    this.add(SimpleAction(ACTION_DELETE, R.string.delete, R.drawable.ic_material_delete, event.root.eventId))
+                }
+
                 if (canQuote(event, messageContent)) {
                     //TODO quote icon
                     this.add(SimpleAction(ACTION_QUOTE, R.string.quote, R.drawable.ic_quote, parcel.eventId))
@@ -148,6 +152,14 @@ class MessageMenuViewModel(initialState: MessageMenuState) : VectorViewModel<Mes
             }
         }
 
+        private fun canRedact(event: TimelineEvent, myUserId: String): Boolean {
+            //Only event of type Event.EVENT_TYPE_MESSAGE are supported for the moment
+            if (event.root.type != EventType.MESSAGE) return false
+            //TODO if user is admin or moderator
+            return event.root.sender == myUserId
+        }
+
+
         private fun canCopy(type: String): Boolean {
             return when (type) {
                 MessageType.MSGTYPE_TEXT,

vector/src/main/java/im/vector/riotredesign/features/home/room/detail/timeline/action/QuickReactionFragment.kt

@@ -119,12 +119,14 @@ class QuickReactionFragment : BaseMvRxFragment() {
         }
 
         if (it.selectionResult != null) {
-            interactionListener?.didQuickReactWith(it.selectionResult.first, it.selectionResult.second, it.eventId)
+            val clikedOn = it.selectionResult.first
+            interactionListener?.didQuickReactWith(clikedOn, QuickReactionViewModel.getOpposite(clikedOn)
+                    ?: "", it.selectionResult.second, it.eventId)
         }
     }
 
     interface InteractionListener {
-        fun didQuickReactWith(clikedOn: String, reactions: List<String>, eventId: String)
+        fun didQuickReactWith(clikedOn: String, opposite: String, reactions: List<String>, eventId: String)
     }
 
     companion object {

vector/src/main/java/im/vector/riotredesign/features/home/room/detail/timeline/action/QuickReactionViewModel.kt

@@ -110,6 +110,16 @@ class QuickReactionViewModel(initialState: QuickReactionState) : VectorViewModel
         val likePositive = "🙂"
         val likeNegative = "😔"
 
+        fun getOpposite(reaction: String): String? {
+            return when (reaction) {
+                agreePositive -> agreeNegative
+                agreeNegative -> agreePositive
+                likePositive -> likeNegative
+                likeNegative -> likePositive
+                else -> null
+            }
+        }
+
         override fun initialState(viewModelContext: ViewModelContext): QuickReactionState? {
             // Args are accessible from the context.
             // val foo = vieWModelContext.args<MyArgs>.foo

vector/src/main/java/im/vector/riotredesign/features/home/room/detail/timeline/factory/MessageItemFactory.kt

@@ -66,7 +66,6 @@ class MessageItemFactory(private val colorProvider: ColorProvider,
                 || nextEvent?.root?.type != EventType.MESSAGE
                 || isNextMessageReceivedMoreThanOneHourAgo
 
-        val messageContent: MessageContent = event.root.content.toModel() ?: return null
         val time = timelineDateFormatter.formatMessageHour(date)
         val avatarUrl = event.senderAvatar
         val memberName = event.senderName ?: event.root.sender ?: ""
@@ -84,8 +83,12 @@ class MessageItemFactory(private val colorProvider: ColorProvider,
                 orderedReactionList = event.annotations?.reactionsSummary?.map { Triple(it.key, it.count, it.addedByMe) }
         )
 
-        //Test for reactions UX
+        if (event.root.unsignedData?.redactedEvent != null) {
-        //informationData.orderedReactionList = listOf( Triple("👍",1,false), Triple("👎",2,false))
+            //message is redacted
+            return buildRedactedItem(informationData, callback)
+        }
+
+        val messageContent: MessageContent = event.root.content.toModel() ?: return null
 
 //        val all = event.root.toContent()
 //        val ev = all.toModel<Event>()
@@ -347,6 +350,19 @@ class MessageItemFactory(private val colorProvider: ColorProvider,
                 }
     }
 
+    private fun buildRedactedItem(informationData: MessageInformationData, callback: TimelineEventController.Callback?): RedactedMessageItem? {
+        return RedactedMessageItem_()
+                .informationData(informationData)
+                .avatarClickListener(
+                        DebouncedClickListener(View.OnClickListener { view ->
+                            callback?.onAvatarClicked(informationData)
+                        }))
+                .memberClickListener(
+                        DebouncedClickListener(View.OnClickListener { view ->
+                            callback?.onMemberNameClicked(informationData)
+                        }))
+    }
+
     private fun linkifyBody(body: CharSequence, callback: TimelineEventController.Callback?): CharSequence {
         val spannable = SpannableStringBuilder(body)
         MatrixLinkify.addLinks(spannable, object : MatrixPermalinkSpan.Callback {

vector/src/main/java/im/vector/riotredesign/features/home/room/detail/timeline/item/AbsMessageItem.kt

@@ -80,17 +80,23 @@ abstract class AbsMessageItem<H : AbsMessageItem.Holder> : BaseEventItem<H>() {
             holder.timeView.text = informationData.time
             holder.memberNameView.text = informationData.memberName
             AvatarRenderer.render(informationData.avatarUrl, informationData.senderId, informationData.memberName?.toString(), holder.avatarImageView)
+            holder.view.setOnClickListener(cellClickListener)
+            holder.view.setOnLongClickListener(longClickListener)
+            holder.avatarImageView.setOnLongClickListener(longClickListener)
+            holder.memberNameView.setOnLongClickListener(longClickListener)
         } else {
             holder.avatarImageView.setOnClickListener(null)
             holder.memberNameView.setOnClickListener(null)
             holder.avatarImageView.visibility = View.GONE
             holder.memberNameView.visibility = View.GONE
             holder.timeView.visibility = View.GONE
+            holder.view.setOnClickListener(null)
+            holder.view.setOnLongClickListener(null)
+            holder.avatarImageView.setOnLongClickListener(null)
+            holder.memberNameView.setOnLongClickListener(null)
         }
-        holder.view.setOnClickListener(cellClickListener)
-        holder.view.setOnLongClickListener(longClickListener)
 
-        if (informationData.orderedReactionList.isNullOrEmpty()) {
+        if (!shouldShowReactionAtBottom() || informationData.orderedReactionList.isNullOrEmpty()) {
             holder.reactionWrapper?.isVisible = false
         } else {
             //inflate if needed
@@ -119,12 +125,12 @@ abstract class AbsMessageItem<H : AbsMessageItem.Holder> : BaseEventItem<H>() {
             if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2 && !holder.view.isInLayout) {
                 holder.reactionFlowHelper?.requestLayout()
             }
-
+            holder.reactionWrapper?.setOnLongClickListener(longClickListener)
         }
     }
 
-    override fun unbind(holder: H) {
+    open fun shouldShowReactionAtBottom() : Boolean {
-        super.unbind(holder)
+        return true
     }
 
     protected fun View.renderSendState() {

vector/src/main/java/im/vector/riotredesign/features/home/room/detail/timeline/item/RedactedMessageItem.kt

@@ -0,0 +1,24 @@
+package im.vector.riotredesign.features.home.room.detail.timeline.item
+
+import com.airbnb.epoxy.EpoxyAttribute
+import com.airbnb.epoxy.EpoxyModelClass
+import im.vector.riotredesign.R
+
+@EpoxyModelClass(layout = R.layout.item_timeline_event_base)
+abstract class RedactedMessageItem : AbsMessageItem<RedactedMessageItem.Holder>() {
+
+    @EpoxyAttribute
+    override lateinit var informationData: MessageInformationData
+
+    override fun getStubType(): Int = STUB_ID
+
+    override fun shouldShowReactionAtBottom() = false
+
+    class Holder : AbsMessageItem.Holder() {
+        override fun getStubId(): Int = STUB_ID
+    }
+
+    companion object {
+        private val STUB_ID = R.id.messageContentRedactedStub
+    }
+}

vector/src/main/res/drawable/redacted_background.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<shape xmlns:android="http://schemas.android.com/apk/res/android">
+    <corners android:radius="10dp" />
+    <solid android:color="?vctr_list_divider_color" />
+</shape>

vector/src/main/res/layout/adapter_item_action_quick_reaction.xml

@@ -15,6 +15,7 @@
         android:background="?android:attr/selectableItemBackground"
         android:clickable="true"
         android:focusable="true"
+        android:textColor="@color/black"
         android:textSize="30sp"
         app:autoSizeTextType="uniform"
         app:layout_constraintBottom_toTopOf="@id/quick_react_agree_text"
@@ -34,10 +35,10 @@
         android:background="?android:attr/selectableItemBackground"
         android:clickable="true"
         android:focusable="true"
+        android:textColor="@color/black"
         android:textSize="30sp"
         app:autoSizeTextType="uniform"
         app:layout_constraintBottom_toBottomOf="@id/quick_react_1_text"
-
         app:layout_constraintEnd_toStartOf="@id/center_guideline"
         app:layout_constraintStart_toEndOf="@id/quick_react_1_text"
         app:layout_constraintTop_toTopOf="@id/quick_react_1_text"
@@ -73,6 +74,7 @@
         android:background="?android:attr/selectableItemBackground"
         android:clickable="true"
         android:focusable="true"
+        android:textColor="@color/black"
         android:textSize="30sp"
         app:autoSizeTextType="uniform"
         app:layout_constraintBottom_toBottomOf="@+id/quick_react_1_text"
@@ -91,6 +93,7 @@
         android:background="?android:attr/selectableItemBackground"
         android:clickable="true"
         android:focusable="true"
+        android:textColor="@color/black"
         android:textSize="30sp"
         app:autoSizeTextType="uniform"
         app:layout_constraintBottom_toBottomOf="@id/quick_react_3_text"

vector/src/main/res/layout/item_timeline_event_base.xml

@@ -81,21 +81,29 @@
         android:layout="@layout/item_timeline_event_file_stub"
         tools:ignore="MissingConstraints" />
 
+    <ViewStub
+        android:id="@+id/messageContentRedactedStub"
+        style="@style/TimelineContentStubLayoutParams"
+        android:layout_height="20dp"
+        android:layout_marginEnd="56dp"
+        android:layout_marginRight="56dp"
+        android:layout="@layout/item_timeline_event_redacted_stub"
+        tools:ignore="MissingConstraints" />
 
 
     <!-- TODO: For now we show 8 reactions maximum, this will need rework when needed-->
     <ViewStub
         android:id="@+id/messageBottomInfo"
-        android:inflatedId="@+id/messageBottomInfo"
         android:layout_width="0dp"
         android:layout_height="wrap_content"
+        android:layout_marginBottom="4dp"
+        android:inflatedId="@+id/messageBottomInfo"
         android:layout="@layout/item_timeline_event_bottom_reactions_stub"
         android:visibility="gone"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toEndOf="@id/messageStartGuideline"
         app:layout_constraintVertical_chainStyle="packed"
-        android:layout_marginBottom="4dp"
         tools:visibility="visible">
 
     </ViewStub>

vector/src/main/res/layout/item_timeline_event_redacted_stub.xml

@@ -0,0 +1,4 @@
+<View xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="20dp"
+    android:background="@drawable/redacted_background" />

vector/src/main/res/layout/reaction_button.xml

@@ -2,9 +2,9 @@
 <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     xmlns:tools="http://schemas.android.com/tools"
-    android:clipChildren="false"
     android:layout_width="44dp"
-    android:layout_height="26dp">
+    android:layout_height="26dp"
+    android:clipChildren="false">
 
 
     <View
@@ -16,21 +16,21 @@
     <im.vector.riotredesign.features.reactions.widget.DotsView
         android:id="@+id/dots"
         android:layout_width="30dp"
-        android:clipChildren="false"
         android:layout_height="30dp"
+        android:clipChildren="false"
         app:layout_constraintBottom_toBottomOf="@+id/reactionText"
+        app:layout_constraintEnd_toEndOf="@+id/reactionText"
         app:layout_constraintStart_toStartOf="@+id/reactionText"
-        app:layout_constraintTop_toTopOf="@+id/reactionText"
+        app:layout_constraintTop_toTopOf="@+id/reactionText" />
-        app:layout_constraintEnd_toEndOf="@+id/reactionText"/>
 
     <im.vector.riotredesign.features.reactions.widget.CircleView
         android:id="@+id/circle"
         android:layout_width="14dp"
         android:layout_height="14dp"
         app:layout_constraintBottom_toBottomOf="@+id/reactionText"
+        app:layout_constraintEnd_toEndOf="@+id/reactionText"
         app:layout_constraintStart_toStartOf="@+id/reactionText"
-        app:layout_constraintTop_toTopOf="@+id/reactionText"
+        app:layout_constraintTop_toTopOf="@+id/reactionText" />
-        app:layout_constraintEnd_toEndOf="@+id/reactionText"/>
 
     <TextView
         android:id="@+id/reactionText"
@@ -40,11 +40,12 @@
         android:layout_marginStart="6dp"
         android:layout_marginLeft="6dp"
         android:gravity="center"
-        tools:text="👍"
+        android:textColor="@color/black"
         android:textSize="13sp"
+        app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent"
-        app:layout_constraintBottom_toBottomOf="parent"/>
+        tools:text="👍" />
 
     <TextView
         android:id="@+id/reactionCount"

vector/src/main/res/values/strings_riotX.xml

@@ -13,4 +13,7 @@
     <string name="reactions_like">Like</string>
     <string name="message_add_reaction">Add Reaction</string>
 
+    <string name="event_redacted_by_user_reason">Event deleted by user</string>
+    <string name="event_redacted_by_admin_reason">Event moderated by room admin</string>
+
 </resources>