From 8e336fd7305f8504f2f1d58579f746885c8b9581 Mon Sep 17 00:00:00 2001
From: Adam Brown <adampsbrown@gmail.com>
Date: Sat, 1 Oct 2022 14:03:30 +0100
Subject: [PATCH] avoiding duplicated room event emissions when watching a
 specific room id

---
 .../kotlin/app/dapk/st/domain/sync/RoomPersistence.kt    | 8 +++-----
 .../main/kotlin/app/dapk/st/messenger/TimelineUseCase.kt | 9 +++------
 2 files changed, 6 insertions(+), 11 deletions(-)

diff --git a/domains/store/src/main/kotlin/app/dapk/st/domain/sync/RoomPersistence.kt b/domains/store/src/main/kotlin/app/dapk/st/domain/sync/RoomPersistence.kt
index 7523e1d..5adf63e 100644
--- a/domains/store/src/main/kotlin/app/dapk/st/domain/sync/RoomPersistence.kt
+++ b/domains/store/src/main/kotlin/app/dapk/st/domain/sync/RoomPersistence.kt
@@ -13,10 +13,7 @@ import app.dapk.st.matrix.sync.RoomStore
 import com.squareup.sqldelight.runtime.coroutines.asFlow
 import com.squareup.sqldelight.runtime.coroutines.mapToList
 import com.squareup.sqldelight.runtime.coroutines.mapToOneNotNull
-import kotlinx.coroutines.flow.Flow
-import kotlinx.coroutines.flow.combine
-import kotlinx.coroutines.flow.distinctUntilChanged
-import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.*
 import kotlinx.serialization.json.Json
 
 private val json = Json
@@ -54,12 +51,13 @@ internal class RoomPersistence(
     override fun latest(roomId: RoomId): Flow<RoomState> {
         val overviewFlow = database.overviewStateQueries.selectRoom(roomId.value).asFlow().mapToOneNotNull().map {
             json.decodeFromString(RoomOverview.serializer(), it)
-        }
+        }.distinctUntilChanged()
 
         return database.roomEventQueries.selectRoom(roomId.value)
             .asFlow()
             .mapToList()
             .map { it.map { json.decodeFromString(RoomEvent.serializer(), it) } }
+            .distinctUntilChanged()
             .combine(overviewFlow) { events, overview ->
                 RoomState(overview, events)
             }
diff --git a/features/messenger/src/main/kotlin/app/dapk/st/messenger/TimelineUseCase.kt b/features/messenger/src/main/kotlin/app/dapk/st/messenger/TimelineUseCase.kt
index c117f39..629c466 100644
--- a/features/messenger/src/main/kotlin/app/dapk/st/messenger/TimelineUseCase.kt
+++ b/features/messenger/src/main/kotlin/app/dapk/st/messenger/TimelineUseCase.kt
@@ -7,10 +7,7 @@ import app.dapk.st.matrix.message.MessageService
 import app.dapk.st.matrix.room.RoomService
 import app.dapk.st.matrix.sync.RoomState
 import app.dapk.st.matrix.sync.SyncService
-import kotlinx.coroutines.flow.Flow
-import kotlinx.coroutines.flow.combine
-import kotlinx.coroutines.flow.map
-import kotlinx.coroutines.flow.onStart
+import kotlinx.coroutines.flow.*
 
 internal typealias ObserveTimelineUseCase = (RoomId, UserId) -> Flow<MessengerState>
 
@@ -25,7 +22,7 @@ internal class TimelineUseCaseImpl(
         return combine(
             roomDatasource(roomId),
             messageService.localEchos(roomId),
-            syncService.events()
+            syncService.events(roomId)
         ) { roomState, localEchos, events ->
             MessengerState(
                 roomState = when {
@@ -45,7 +42,7 @@ internal class TimelineUseCaseImpl(
     }
 
     private fun roomDatasource(roomId: RoomId) = combine(
-        syncService.startSyncing().map { false }.onStart { emit(true) },
+        syncService.startSyncing().map { false }.onStart { emit(true) }.filter { it },
         syncService.room(roomId)
     ) { _, room -> room }
 }