Timeline: map on background thread

features/messages/src/main/java/io/element/android/x/features/messages/MessageTimelineItemStateMapper.kt

@@ -0,0 +1,67 @@
+package io.element.android.x.features.messages
+
+import io.element.android.x.features.messages.model.MessagesItemGroupPosition
+import io.element.android.x.features.messages.model.MessagesTimelineItemState
+import io.element.android.x.matrix.core.UserId
+import io.element.android.x.matrix.room.MatrixRoom
+import io.element.android.x.matrix.timeline.MatrixTimelineItem
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.withContext
+import org.matrix.rustcomponents.sdk.MessageType
+
+class MessageTimelineItemStateMapper(
+    private val myUserId: UserId,
+    private val room: MatrixRoom,
+    private val dispatcher: CoroutineDispatcher,
+) {
+
+    suspend fun map(timelineItems: List<MatrixTimelineItem>): List<MessagesTimelineItemState> =
+        withContext(dispatcher) {
+            val messagesTimelineItemState = ArrayList<MessagesTimelineItemState>()
+            for (index in timelineItems.indices.reversed()) {
+                val currentTimelineItem = timelineItems[index]
+                val timelineItemState = when (currentTimelineItem) {
+                    is MatrixTimelineItem.Event -> {
+                        val prevTimelineItem =
+                            timelineItems.getOrNull(index - 1) as? MatrixTimelineItem.Event
+                        val nextTimelineItem =
+                            timelineItems.getOrNull(index + 1) as? MatrixTimelineItem.Event
+                        val currentSender = currentTimelineItem.event.sender()
+                        val previousSender = prevTimelineItem?.event?.sender()
+                        val nextSender = nextTimelineItem?.event?.sender()
+
+                        val groupPosition = when {
+                            previousSender != currentSender && nextSender == currentSender -> MessagesItemGroupPosition.First
+                            previousSender == currentSender && nextSender == currentSender -> MessagesItemGroupPosition.Middle
+                            previousSender == currentSender && nextSender != currentSender -> MessagesItemGroupPosition.Last
+                            else -> MessagesItemGroupPosition.None
+                        }
+                        val messageType =
+                            currentTimelineItem.event.content().asMessage()?.msgtype()
+                        val contentStr = when (messageType) {
+                            is MessageType.Emote -> messageType.content.body
+                            is MessageType.Image -> messageType.content.body
+                            is MessageType.Notice -> messageType.content.body
+                            is MessageType.Text -> messageType.content.body
+                            null -> null
+                        }
+                        MessagesTimelineItemState.MessageEvent(
+                            id = currentTimelineItem.event.eventId() ?: "",
+                            sender = currentTimelineItem.event.sender(),
+                            content = contentStr,
+                            isMine = currentTimelineItem.event.isOwn(),
+                            groupPosition = groupPosition
+                        )
+                    }
+                    is MatrixTimelineItem.Virtual -> MessagesTimelineItemState.Virtual(
+                        "virtual_item_$index"
+                    )
+                    MatrixTimelineItem.Other -> continue
+                }
+                messagesTimelineItemState.add(timelineItemState)
+            }
+            messagesTimelineItemState
+        }
+
+
+}

features/messages/src/main/java/io/element/android/x/features/messages/MessagesViewModel.kt

@@ -5,19 +5,16 @@ import com.airbnb.mvrx.MavericksViewModelFactory
 import com.airbnb.mvrx.ViewModelContext
 import io.element.android.x.designsystem.components.avatar.AvatarData
 import io.element.android.x.designsystem.components.avatar.AvatarSize
-import io.element.android.x.features.messages.model.MessagesItemGroupPosition
-import io.element.android.x.features.messages.model.MessagesTimelineItemState
 import io.element.android.x.features.messages.model.MessagesViewState
 import io.element.android.x.matrix.MatrixClient
 import io.element.android.x.matrix.MatrixInstance
 import io.element.android.x.matrix.room.MatrixRoom
 import io.element.android.x.matrix.timeline.MatrixTimeline
-import io.element.android.x.matrix.timeline.MatrixTimelineItem
+import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.launch
-import org.matrix.rustcomponents.sdk.MessageType
 import org.matrix.rustcomponents.sdk.mediaSourceFromUrl
 
 private const val PAGINATION_COUNT = 50
@@ -26,6 +23,7 @@ class MessagesViewModel(
     private val client: MatrixClient,
     private val room: MatrixRoom,
     private val timeline: MatrixTimeline,
+    private val messageTimelineItemStateMapper: MessageTimelineItemStateMapper,
     private val initialState: MessagesViewState
 ) :
     MavericksViewModel<MessagesViewState>(initialState) {
@@ -39,7 +37,15 @@ class MessagesViewModel(
             val matrix = MatrixInstance.getInstance()
             val client = matrix.activeClient()
             val room = client.getRoom(state.roomId) ?: return null
-            return MessagesViewModel(client, room, room.timeline(), state)
+            val messageTimelineItemStateMapper =
+                MessageTimelineItemStateMapper(client.userId(), room, Dispatchers.Default)
+            return MessagesViewModel(
+                client,
+                room,
+                room.timeline(),
+                messageTimelineItemStateMapper,
+                state
+            )
         }
     }
 
@@ -67,53 +73,7 @@ class MessagesViewModel(
             }.launchIn(viewModelScope)
 
         timeline.timelineItems()
-            .map { timelineItems ->
+            .map(messageTimelineItemStateMapper::map)
-                val messagesTimelineItemState = ArrayList<MessagesTimelineItemState>()
-                for (index in timelineItems.indices.reversed()) {
-                    val currentTimelineItem = timelineItems[index]
-                    val timelineItemState = when (currentTimelineItem) {
-                        is MatrixTimelineItem.Event -> {
-                            val prevTimelineItem =
-                                timelineItems.getOrNull(index - 1) as? MatrixTimelineItem.Event
-                            val nextTimelineItem =
-                                timelineItems.getOrNull(index + 1) as? MatrixTimelineItem.Event
-                            val currentSender = currentTimelineItem.event.sender()
-                            val previousSender = prevTimelineItem?.event?.sender()
-                            val nextSender = nextTimelineItem?.event?.sender()
-
-                            val groupPosition = when {
-                                previousSender != currentSender && nextSender == currentSender -> MessagesItemGroupPosition.First
-                                previousSender == currentSender && nextSender == currentSender -> MessagesItemGroupPosition.Middle
-                                previousSender == currentSender && nextSender != currentSender -> MessagesItemGroupPosition.Last
-                                else -> MessagesItemGroupPosition.None
-                            }
-                            val messageType =
-                                currentTimelineItem.event.content().asMessage()?.msgtype()
-                            val contentStr = when (messageType) {
-                                is MessageType.Emote -> messageType.content.body
-                                is MessageType.Image -> messageType.content.body
-                                is MessageType.Notice -> messageType.content.body
-                                is MessageType.Text -> messageType.content.body
-                                null -> null
-                            }
-
-                            MessagesTimelineItemState.MessageEvent(
-                                id = currentTimelineItem.event.eventId() ?: "",
-                                sender = currentTimelineItem.event.sender(),
-                                content = contentStr,
-                                isMine = currentTimelineItem.event.sender() == client.userId().value,
-                                groupPosition = groupPosition
-                            )
-                        }
-                        is MatrixTimelineItem.Virtual -> MessagesTimelineItemState.Virtual(
-                            "virtual_item_$index"
-                        )
-                        MatrixTimelineItem.Other -> continue
-                    }
-                    messagesTimelineItemState.add(timelineItemState)
-                }
-                messagesTimelineItemState
-            }
             .execute {
                 copy(timelineItems = it)
             }