Ensure gallery is paginating to get new items.

libraries/mediaviewer/impl/src/main/kotlin/io/element/android/libraries/mediaviewer/impl/gallery/MediaGalleryView.kt

@@ -198,6 +198,13 @@ private fun MediaGalleryPage(
 ) {
     val groupedMediaItems = state.groupedMediaItems
     if (groupedMediaItems.isLoadingItems(mode)) {
+        // Need to trigger a pagination now if there is only one LoadingIndicator.
+        (groupedMediaItems.dataOrNull()
+            ?.getItems(mode)?.singleOrNull() as? MediaItem.LoadingIndicator)?.let { item ->
+            LaunchedEffect(item.timestamp) {
+                state.eventSink(MediaGalleryEvents.LoadMore(item.direction))
+            }
+        }
         LoadingContent(mode)
     } else {
         when (groupedMediaItems) {

libraries/mediaviewer/impl/src/main/kotlin/io/element/android/libraries/mediaviewer/impl/viewer/MediaViewerDataSource.kt

@@ -71,14 +71,26 @@ class MediaViewerDataSource(
     fun dataFlow(): Flow<PersistentList<MediaViewerPageData>> {
         return galleryDataSource.groupedMediaItemsFlow()
             .map { groupedItems ->
-                if (groupedItems is AsyncData.Failure) {
+                when (groupedItems) {
-                    persistentListOf(
+                    AsyncData.Uninitialized,
-                        MediaViewerPageData.Failure(groupedItems.error),
+                    is AsyncData.Loading -> {
-                    )
+                        persistentListOf(
-                } else {
+                            MediaViewerPageData.Loading(
-                    val mediaItems = groupedItems.dataOrNull()?.getItems(galleryMode).orEmpty()
+                                direction = Timeline.PaginationDirection.BACKWARDS,
-                    withContext(dispatcher) {
+                                timestamp = systemClock.epochMillis(),
-                        buildMediaViewerPageList(mediaItems)
+                            )
+                        )
+                    }
+                    is AsyncData.Failure -> {
+                        persistentListOf(
+                            MediaViewerPageData.Failure(groupedItems.error),
+                        )
+                    }
+                    is AsyncData.Success -> {
+                        withContext(dispatcher) {
+                            val mediaItems = groupedItems.data.getItems(galleryMode)
+                            buildMediaViewerPageList(mediaItems)
+                        }
                     }
                 }
             }
@@ -117,14 +129,6 @@ class MediaViewerDataSource(
                 )
             }
         }
-        if (isEmpty()) {
-            add(
-                MediaViewerPageData.Loading(
-                    direction = Timeline.PaginationDirection.BACKWARDS,
-                    timestamp = systemClock.epochMillis(),
-                )
-            )
-        }
     }.toPersistentList()
 
     fun clearLoadingError(data: MediaViewerPageData.MediaViewerData) {

libraries/mediaviewer/impl/src/test/kotlin/io/element/android/libraries/mediaviewer/impl/viewer/MediaViewerDataSourceTest.kt

@@ -91,13 +91,7 @@ class MediaViewerDataSourceTest {
                 )
             )
             val result = awaitItem()
-            assertThat(result).hasSize(1)
+            assertThat(result).isEmpty()
-            assertThat(result.first()).isEqualTo(
-                MediaViewerPageData.Loading(
-                    direction = Timeline.PaginationDirection.BACKWARDS,
-                    timestamp = A_FAKE_TIMESTAMP,
-                )
-            )
         }
     }
 

libraries/mediaviewer/impl/src/test/kotlin/io/element/android/libraries/mediaviewer/impl/viewer/MediaViewerPresenterTest.kt

@@ -72,7 +72,7 @@ class MediaViewerPresenterTest {
         )
         presenter.test {
             val initialState = awaitFirstItem()
-            assertThat(initialState.listData.singleOrNull()).isInstanceOf(MediaViewerPageData.Loading::class.java)
+            assertThat(initialState.listData).isEmpty()
             assertThat(initialState.currentIndex).isEqualTo(0)
             assertThat(initialState.snackbarMessage).isNull()
             assertThat(initialState.canShowInfo).isTrue()
@@ -90,7 +90,7 @@ class MediaViewerPresenterTest {
         )
         presenter.test {
             val initialState = awaitFirstItem()
-            assertThat(initialState.listData.singleOrNull()).isInstanceOf(MediaViewerPageData.Loading::class.java)
+            assertThat(initialState.listData).isEmpty()
             assertThat(initialState.currentIndex).isEqualTo(0)
             assertThat(initialState.snackbarMessage).isNull()
             assertThat(initialState.canShowInfo).isFalse()
@@ -108,7 +108,7 @@ class MediaViewerPresenterTest {
         )
         presenter.test {
             val initialState = awaitFirstItem()
-            assertThat(initialState.listData.singleOrNull()).isInstanceOf(MediaViewerPageData.Loading::class.java)
+            assertThat(initialState.listData).isEmpty()
             assertThat(initialState.currentIndex).isEqualTo(0)
             assertThat(initialState.snackbarMessage).isNull()
             assertThat(initialState.canShowInfo).isTrue()
@@ -127,7 +127,7 @@ class MediaViewerPresenterTest {
         )
         presenter.test {
             val initialState = awaitFirstItem()
-            assertThat(initialState.listData.singleOrNull()).isInstanceOf(MediaViewerPageData.Loading::class.java)
+            assertThat(initialState.listData).isEmpty()
             assertThat(initialState.currentIndex).isEqualTo(0)
             assertThat(initialState.snackbarMessage).isNull()
             assertThat(initialState.canShowInfo).isTrue()
@@ -146,7 +146,7 @@ class MediaViewerPresenterTest {
         val anImage = aMediaItemImage()
         presenter.test {
             val initialState = awaitFirstItem()
-            assertThat(initialState.listData.singleOrNull()).isInstanceOf(MediaViewerPageData.Loading::class.java)
+            assertThat(initialState.listData).isEmpty()
             mediaGalleryDataSource.emitGroupedMediaItems(
                 AsyncData.Success(
                     GroupedMediaItems(