[FEATURE] Add Pull to Next at the bottom of Feed

androidApp/src/main/kotlin/com/prof18/feedflow/android/MainActivity.kt

@@ -289,6 +289,7 @@ class MainActivity : BaseThemeActivity() {
                             backStack.add(feedSource.toEditFeed())
                         },
                         onFeedSuggestionsClick = { backStack.add(FeedSuggestions) },
+                        onNavigateToNextFeed = { homeViewModel.onNavigateToNextFeed() },
                     )
                 }
 

androidApp/src/main/kotlin/com/prof18/feedflow/android/home/HomeScreen.android.kt

@@ -18,6 +18,7 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import androidx.window.core.layout.WindowWidthSizeClass
 import com.prof18.feedflow.android.BrowserManager
 import com.prof18.feedflow.android.categoryselection.EditCategorySheet
 import com.prof18.feedflow.android.openShareSheet
@@ -29,11 +30,15 @@ import com.prof18.feedflow.core.model.LinkOpeningPreference
 import com.prof18.feedflow.core.model.shouldOpenInBrowser
 import com.prof18.feedflow.shared.presentation.ChangeFeedCategoryViewModel
 import com.prof18.feedflow.shared.presentation.HomeViewModel
+import com.prof18.feedflow.shared.presentation.model.NextFeedPreviewState
+import com.prof18.feedflow.shared.presentation.model.NextFeedPreviewState.NextFeedPreviewDisabledState
+import com.prof18.feedflow.shared.presentation.model.NextFeedPreviewState.NextFeedPreviewEnabledState
 import com.prof18.feedflow.shared.presentation.model.UIErrorState
 import com.prof18.feedflow.shared.ui.home.AdaptiveHomeView
 import com.prof18.feedflow.shared.ui.home.FeedListActions
 import com.prof18.feedflow.shared.ui.home.FeedManagementActions
 import com.prof18.feedflow.shared.ui.home.HomeDisplayState
+import com.prof18.feedflow.shared.ui.home.NextFeedDisplayState
 import com.prof18.feedflow.shared.ui.home.ShareBehavior
 import com.prof18.feedflow.shared.ui.home.WindowSizeClass
 import com.prof18.feedflow.shared.ui.home.components.LoadingOperationDialog
@@ -49,8 +54,9 @@ internal fun HomeScreen(
     onSearchClick: () -> Unit,
     onAccountsClick: () -> Unit,
     onEditFeedClick: (FeedSource) -> Unit,
-    onImportExportClick: () -> Unit = {},
     onFeedSuggestionsClick: () -> Unit,
+    onNavigateToNextFeed: () -> Unit,
+    onImportExportClick: () -> Unit = {},
 ) {
     val browserManager = koinInject<BrowserManager>()
     val changeFeedCategoryViewModel: ChangeFeedCategoryViewModel = koinInject()
@@ -59,6 +65,7 @@ internal fun HomeScreen(
     val feedState by homeViewModel.feedState.collectAsStateWithLifecycle()
     val navDrawerState by homeViewModel.navDrawerState.collectAsStateWithLifecycle()
     val currentFeedFilter by homeViewModel.currentFeedFilter.collectAsStateWithLifecycle()
+    val nextFeedPreviewState: NextFeedPreviewState by homeViewModel.nextFeedPreviewState.collectAsStateWithLifecycle()
     val unReadCount by homeViewModel.unreadCountFlow.collectAsStateWithLifecycle(initialValue = 0)
     val feedFontSizes by homeViewModel.feedFontSizeState.collectAsStateWithLifecycle()
     val swipeActions by homeViewModel.swipeActions.collectAsStateWithLifecycle()
@@ -130,6 +137,7 @@ internal fun HomeScreen(
         swipeActions = swipeActions,
         feedLayout = feedLayout,
         isSyncUploadRequired = isSyncUploadRequired,
+        nextFeedDisplayState = nextFeedPreviewState.asDisplayState(),
     )
 
     val feedListActions = FeedListActions(
@@ -168,8 +176,8 @@ internal fun HomeScreen(
 
     val windowSizeClass = currentWindowAdaptiveInfo().windowSizeClass
     val adaptiveWindowSizeClass = when (windowSizeClass.windowWidthSizeClass) {
-        androidx.window.core.layout.WindowWidthSizeClass.COMPACT -> WindowSizeClass.Compact
-        androidx.window.core.layout.WindowWidthSizeClass.MEDIUM -> WindowSizeClass.Medium
+        WindowWidthSizeClass.COMPACT -> WindowSizeClass.Compact
+        WindowWidthSizeClass.MEDIUM -> WindowSizeClass.Medium
         else -> WindowSizeClass.Expanded
     }
 
@@ -208,6 +216,7 @@ internal fun HomeScreen(
         onEmptyStateClick = {
             showNoFeedsBottomSheet = true
         },
+        onNavigateToNextFeed = onNavigateToNextFeed,
     )
 
     if (showChangeCategorySheet) {
@@ -278,3 +287,8 @@ private fun openUrl(
         }
     }
 }
+
+fun NextFeedPreviewState.asDisplayState(): NextFeedDisplayState = when (this) {
+    is NextFeedPreviewDisabledState -> NextFeedDisplayState.NextFeedDisplayDisabledState
+    is NextFeedPreviewEnabledState -> NextFeedDisplayState.NextFeedDisplayEnabledState(this.title)
+}

desktopApp/src/jvmMain/kotlin/com/prof18/feedflow/desktop/home/HomeScreen.desktop.kt

@@ -32,6 +32,7 @@ import com.prof18.feedflow.shared.presentation.model.UIErrorState
 import com.prof18.feedflow.shared.ui.home.FeedListActions
 import com.prof18.feedflow.shared.ui.home.FeedManagementActions
 import com.prof18.feedflow.shared.ui.home.HomeDisplayState
+import com.prof18.feedflow.shared.ui.home.NextFeedDisplayState.NextFeedDisplayDisabledState
 import com.prof18.feedflow.shared.ui.home.ShareBehavior
 import com.prof18.feedflow.shared.ui.home.components.LoadingOperationDialog
 import com.prof18.feedflow.shared.ui.utils.LocalFeedFlowStrings
@@ -132,6 +133,7 @@ internal fun HomeScreen(
         currentFeedFilter = currentFeedFilter,
         swipeActions = swipeActions,
         feedLayout = feedLayout,
+        nextFeedDisplayState = NextFeedDisplayDisabledState,
     )
 
     val openReaderArticle: (FeedItemUrlInfo) -> Unit = { article ->

i18n/src/commonMain/resources/locale/values/strings.xml

@@ -307,6 +307,7 @@
     <string name="scroll_to_top_button_content_description">Scroll to top</string>
     <string name="previous_article">Previous article</string>
     <string name="next_article">Next article</string>
+    <string name="next">Next</string>
     <string name="settings_theme">Theme</string>
     <string name="settings_theme_system">System</string>
     <string name="settings_theme_light">Light</string>

shared/src/commonMain/kotlin/com/prof18/feedflow/shared/di/Koin.kt

@@ -50,6 +50,7 @@ import com.prof18.feedflow.shared.presentation.FeedSourceListViewModel
 import com.prof18.feedflow.shared.presentation.FeedSuggestionsViewModel
 import com.prof18.feedflow.shared.presentation.FeedbinSyncViewModel
 import com.prof18.feedflow.shared.presentation.FreshRssSyncViewModel
+import com.prof18.feedflow.shared.presentation.GetNextFeedFilterOrNullUseCase
 import com.prof18.feedflow.shared.presentation.HomeViewModel
 import com.prof18.feedflow.shared.presentation.ImportExportViewModel
 import com.prof18.feedflow.shared.presentation.MainSettingsViewModel
@@ -197,6 +198,7 @@ private fun getCoreModule(appConfig: AppConfig) = module {
             feedCategoryRepository = get(),
             feedStateRepository = get(),
             feedFetcherRepository = get(),
+            getNextFeedFilterOrNullUseCase = get(),
         )
     }
 
@@ -577,6 +579,12 @@ private fun getCoreModule(appConfig: AppConfig) = module {
             backgroundSyncScheduler = get(),
         )
     }
+
+    single {
+        GetNextFeedFilterOrNullUseCase(
+            feedSourcesRepository = get(),
+        )
+    }
 }
 
 internal expect fun platformLogWriters(): List<LogWriter>

shared/src/commonMain/kotlin/com/prof18/feedflow/shared/domain/feed/FeedSourcesRepository.kt

@@ -72,6 +72,9 @@ internal class FeedSourcesRepository(
     fun getFeedSources(): Flow<List<FeedSource>> =
         databaseHelper.getFeedSourcesFlow()
 
+    fun getFeedSourcesWithUnreadCount(): Flow<List<FeedSourceWithUnreadCount>> =
+        databaseHelper.getFeedSourcesWithUnreadCountFlow()
+
     suspend fun deleteFeed(feedSource: FeedSource) {
         when (accountsRepository.getCurrentSyncAccount()) {
             SyncAccounts.FRESH_RSS, SyncAccounts.MINIFLUX, SyncAccounts.BAZQUX -> {

shared/src/commonMain/kotlin/com/prof18/feedflow/shared/presentation/GetNextFeedFilterOrNullUseCase.kt

@@ -0,0 +1,57 @@
+package com.prof18.feedflow.shared.presentation
+
+import com.prof18.feedflow.core.model.FeedFilter
+import com.prof18.feedflow.shared.domain.feed.FeedSourcesRepository
+import kotlinx.coroutines.flow.first
+
+class GetNextFeedFilterOrNullUseCase internal constructor(
+    private val feedSourcesRepository: FeedSourcesRepository,
+) {
+
+    suspend operator fun invoke(
+        currentFeedFilter: FeedFilter,
+    ): FeedFilter? {
+        when (currentFeedFilter) {
+            is FeedFilter.Category -> {
+                val unreadCategoryList = feedSourcesRepository
+                    .observeFeedSourcesByCategoryWithUnreadCount()
+                    .first()
+                    .mapValues { source -> source.value.sumOf { it.unreadCount } }
+                    .filter { it.value > 0 }
+                    .keys
+                    .filterNotNull()
+
+                val currentCategoryIndex = unreadCategoryList
+                    .indexOfFirst { it.id == currentFeedFilter.feedCategory.id }
+
+                return FeedFilter.Category(
+                    feedCategory = unreadCategoryList
+                        .drop(currentCategoryIndex + 1)
+                        .firstOrNull()
+                        ?: return null,
+                )
+            }
+            is FeedFilter.Source -> {
+                val feedSources = feedSourcesRepository.getFeedSourcesWithUnreadCount().first()
+                    .filter {
+                        it.feedSource.category?.id == currentFeedFilter.feedSource.category?.id
+                    }
+
+                val currentSourceIndex = feedSources.indexOfFirst {
+                    it.feedSource.id == currentFeedFilter.feedSource.id
+                }
+
+                if (currentSourceIndex == -1) return null
+
+                val nextUnreadSource = feedSources
+                    .drop(currentSourceIndex + 1)
+                    .firstOrNull { it.unreadCount > 0 }
+
+                return FeedFilter.Source(
+                    feedSource = nextUnreadSource?.feedSource ?: return null,
+                )
+            }
+            else -> return null
+        }
+    }
+}

shared/src/commonMain/kotlin/com/prof18/feedflow/shared/presentation/HomeViewModel.kt

@@ -29,6 +29,7 @@ import com.prof18.feedflow.shared.domain.feedsync.FeedSyncRepository
 import com.prof18.feedflow.shared.presentation.model.DatabaseError
 import com.prof18.feedflow.shared.presentation.model.DeleteFeedSourceError
 import com.prof18.feedflow.shared.presentation.model.FeedErrorState
+import com.prof18.feedflow.shared.presentation.model.NextFeedPreviewState
 import com.prof18.feedflow.shared.presentation.model.SyncError
 import com.prof18.feedflow.shared.presentation.model.UIErrorState
 import kotlinx.collections.immutable.ImmutableList
@@ -57,6 +58,7 @@ class HomeViewModel internal constructor(
     private val feedCategoryRepository: FeedCategoryRepository,
     private val feedStateRepository: FeedStateRepository,
     private val feedFetcherRepository: FeedFetcherRepository,
+    private val getNextFeedFilterOrNullUseCase: GetNextFeedFilterOrNullUseCase,
 ) : ViewModel() {
 
     // Loading
@@ -80,6 +82,11 @@ class HomeViewModel internal constructor(
     private val refreshTriggerMutableState = MutableStateFlow(0)
     val refreshTriggerState: StateFlow<Int> = refreshTriggerMutableState.asStateFlow()
 
+    private val nextFeedPreviewMutableState: MutableStateFlow<NextFeedPreviewState> = MutableStateFlow(
+        NextFeedPreviewState.NextFeedPreviewDisabledState,
+    )
+    val nextFeedPreviewState: StateFlow<NextFeedPreviewState> = nextFeedPreviewMutableState.asStateFlow()
+
     private var lastUpdateIndex = 0
     private var hasTriggeredAppLaunch = false
 
@@ -332,6 +339,28 @@ class HomeViewModel internal constructor(
             feedStateRepository.updateFeedFilter(selectedFeedFilter)
             lastUpdateIndex = 0
         }
+
+        updateNextFeedPreview(selectedFeedFilter)
+    }
+
+    fun updateNextFeedPreview(currentFeedFilter: FeedFilter) {
+        viewModelScope.launch {
+            nextFeedPreviewMutableState.update {
+                val nextFeed = getNextFeedFilterOrNullUseCase(currentFeedFilter)
+
+                when (nextFeed) {
+                    is FeedFilter.Category -> NextFeedPreviewState.NextFeedPreviewEnabledState(
+                        feedFilter = nextFeed,
+                        title = nextFeed.feedCategory.title,
+                    )
+                    is FeedFilter.Source -> NextFeedPreviewState.NextFeedPreviewEnabledState(
+                        feedFilter = nextFeed,
+                        title = nextFeed.feedSource.title,
+                    )
+                    else -> NextFeedPreviewState.NextFeedPreviewDisabledState
+                }
+            }
+        }
     }
 
     fun updateReadStatus(feedItemId: FeedItemId, read: Boolean) {
@@ -385,5 +414,14 @@ class HomeViewModel internal constructor(
         }
     }
 
+    fun onNavigateToNextFeed() {
+        when (val nextFeed = nextFeedPreviewState.value) {
+            is NextFeedPreviewState.NextFeedPreviewEnabledState -> {
+                onFeedFilterSelected(selectedFeedFilter = nextFeed.feedFilter)
+            }
+            is NextFeedPreviewState.NextFeedPreviewDisabledState -> {}
+        }
+    }
+
     fun getCurrentThemeMode() = settingsRepository.getThemeMode()
 }

shared/src/commonMain/kotlin/com/prof18/feedflow/shared/presentation/model/NextFeedPreviewState.kt

@@ -0,0 +1,12 @@
+package com.prof18.feedflow.shared.presentation.model
+
+import com.prof18.feedflow.core.model.FeedFilter
+
+sealed class NextFeedPreviewState {
+    data class NextFeedPreviewEnabledState(
+        val title: String,
+        val feedFilter: FeedFilter,
+    ) : NextFeedPreviewState()
+
+    data object NextFeedPreviewDisabledState : NextFeedPreviewState()
+}