Add total unread notification count to home screen (#7891)

* Add total unread notification count to home screen

This will be calculated on each sync heartbeat (for now, using the state updates for the room list service).

* Simplify `counter` parameter logic

* Read the total unread count when the home screen is first displayed

---------

Co-authored-by: Benoit Marty <benoitm@element.io>

features/home/impl/src/main/kotlin/io/element/android/features/home/impl/HomePresenter.kt

@@ -14,6 +14,7 @@ import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.derivedStateOf
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableIntStateOf
+import androidx.compose.runtime.produceState
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.saveable.rememberSaveable
@@ -34,9 +35,14 @@ import io.element.android.libraries.matrix.api.MatrixClient
 import io.element.android.libraries.matrix.api.sync.SyncService
 import io.element.android.libraries.sessionstorage.api.SessionStore
 import kotlinx.collections.immutable.persistentListOf
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.FlowPreview
 import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.debounce
 import kotlinx.coroutines.flow.filter
+import kotlinx.coroutines.flow.mapLatest
 import kotlinx.coroutines.launch
+import kotlin.time.Duration.Companion.milliseconds
 
 @Inject
 class HomePresenter(
@@ -53,10 +59,20 @@ class HomePresenter(
 ) : Presenter<HomeState> {
     private val currentUserWithNeighborsBuilder = CurrentUserWithNeighborsBuilder()
 
+    @OptIn(FlowPreview::class, ExperimentalCoroutinesApi::class)
     @Composable
     override fun present(): HomeState {
         val coroutineState = rememberCoroutineScope()
         val matrixUser by client.userProfile.collectAsState()
+
+        val totalUnreadCount by produceState(client.totalUnreadCount().getOrDefault(0).toInt()) {
+            syncService.heartBeat
+                // Delay the heartbeat so the SDK has time to update the unread count before we read it.
+                .debounce(100.milliseconds)
+                .mapLatest { client.totalUnreadCount().getOrDefault(0).toInt() }
+                .collect { value = it }
+        }
+
         val currentUserAndNeighbors by remember {
             combine(
                 client.userProfile,
@@ -130,6 +146,7 @@ class HomePresenter(
             snackbarMessage = snackbarMessage,
             canReportBug = canReportBug,
             showMultiAccountAnnouncement = showMultiAccountAnnouncement,
+            totalUnreadCount = totalUnreadCount,
             eventSink = ::handleEvent,
         )
     }

features/home/impl/src/main/kotlin/io/element/android/features/home/impl/HomeState.kt

@@ -29,6 +29,7 @@ data class HomeState(
     val snackbarMessage: SnackbarMessage?,
     val canReportBug: Boolean,
     val showMultiAccountAnnouncement: Boolean,
+    val totalUnreadCount: Int,
     val eventSink: (HomeEvent) -> Unit,
 ) {
     val isBackHandlerEnabled = currentHomeNavigationBarItem != HomeNavigationBarItem.Chats || roomListState.spaceFiltersState is SpaceFiltersState.Selected

features/home/impl/src/main/kotlin/io/element/android/features/home/impl/HomeStatePreviewParam.kt

@@ -64,6 +64,7 @@ internal fun aHomeState(
     homeSpacesState: HomeSpacesState = aHomeSpacesState(),
     canReportBug: Boolean = true,
     showMultiAccountAnnouncement: Boolean = false,
+    totalUnreadCount: Int = 0,
     eventSink: (HomeEvent) -> Unit = {}
 ) = HomeState(
     currentUserAndNeighbors = currentUserAndNeighbors.toImmutableList(),
@@ -75,5 +76,6 @@ internal fun aHomeState(
     currentHomeNavigationBarItem = currentHomeNavigationBarItem,
     roomListState = roomListState,
     homeSpacesState = homeSpacesState,
+    totalUnreadCount = totalUnreadCount,
     eventSink = eventSink,
 )

features/home/impl/src/main/kotlin/io/element/android/features/home/impl/HomeView.kt

@@ -259,6 +259,7 @@ private fun HomeScaffold(
                         }
                     }
                 },
+                totalUnreadCount = state.totalUnreadCount,
             )
         },
         floatingActionButtonPosition = FabPosition.Center,
@@ -341,6 +342,7 @@ private fun HomeFloatingActionButton(
 
 @Composable
 private fun HomeBottomBar(
+    totalUnreadCount: Int,
     currentHomeNavigationBarItem: HomeNavigationBarItem,
     onItemClick: (HomeNavigationBarItem) -> Unit,
     modifier: Modifier = Modifier,
@@ -361,6 +363,7 @@ private fun HomeBottomBar(
                 tooltipLabel = stringResource(item.labelRes),
                 isSelected = isSelected,
                 onClick = { onItemClick(item) },
+                counter = totalUnreadCount.takeIf { item == HomeNavigationBarItem.Chats && it > 0 }
             )
         }
     }

features/home/impl/src/test/kotlin/io/element/android/features/home/impl/HomePresenterTest.kt

@@ -40,9 +40,11 @@ import io.element.android.tests.testutils.lambda.lambdaRecorder
 import io.element.android.tests.testutils.lambda.value
 import io.element.android.tests.testutils.test
 import kotlinx.coroutines.flow.flowOf
+import kotlinx.coroutines.test.advanceTimeBy
 import kotlinx.coroutines.test.runTest
 import org.junit.Rule
 import org.junit.Test
+import kotlin.time.Duration.Companion.milliseconds
 
 class HomePresenterTest {
     @get:Rule
@@ -117,6 +119,38 @@ class HomePresenterTest {
         }
     }
 
+    @Test
+    fun `present - total unread count is updated on sync heartbeat`() = runTest {
+        var unreadCount = 0L
+        val syncService = FakeSyncService()
+        val presenter = createHomePresenter(
+            client = FakeMatrixClient(totalUnreadCountResult = { Result.success(unreadCount) }),
+            syncService = syncService,
+        )
+        presenter.test {
+            assertThat(awaitItem().totalUnreadCount).isEqualTo(0)
+            unreadCount = 5
+            syncService.emitHeartBeat()
+            advanceTimeBy(200.milliseconds)
+            assertThat(awaitItem().totalUnreadCount).isEqualTo(5)
+        }
+    }
+
+    @Test
+    fun `present - total unread count defaults to 0 when the SDK call fails`() = runTest {
+        val syncService = FakeSyncService()
+        val presenter = createHomePresenter(
+            client = FakeMatrixClient(totalUnreadCountResult = { Result.failure(AN_EXCEPTION) }),
+            syncService = syncService,
+        )
+        presenter.test {
+            assertThat(awaitItem().totalUnreadCount).isEqualTo(0)
+            syncService.emitHeartBeat()
+            advanceTimeBy(200.milliseconds)
+            expectNoEvents()
+        }
+    }
+
     @Test
     fun `present - should start with no user and then load user with error`() = runTest {
         val matrixClient = FakeMatrixClient(
@@ -245,6 +279,16 @@ class HomePresenterTest {
                 .with(value(Announcement.MultiAccount))
         }
     }
+
+    @Test
+    fun `present - total unread count is loaded in the initial state`() = runTest {
+        val presenter = createHomePresenter(
+            client = FakeMatrixClient(totalUnreadCountResult = { Result.success(5) }),
+        )
+        presenter.test {
+            assertThat(awaitItem().totalUnreadCount).isEqualTo(5)
+        }
+    }
 }
 
 internal fun createHomePresenter(