Use proper category when getting random item

Fixes #8700

app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryScreenModel.kt

@@ -87,8 +87,7 @@ class LibraryScreenModel(
     private val trackManager: TrackManager = Injekt.get(),
 ) : StateScreenModel<LibraryScreenModel.State>(State()) {
 
-    // This is active category INDEX NUMBER
-    var activeCategory: Int by libraryPreferences.lastUsedCategory().asState(coroutineScope)
+    var activeCategoryIndex: Int by libraryPreferences.lastUsedCategory().asState(coroutineScope)
 
     val isDownloadOnly: Boolean by preferences.downloadedOnly().asState(coroutineScope)
     val isIncognitoMode: Boolean by preferences.incognitoMode().asState(coroutineScope)
@@ -588,7 +587,7 @@ class LibraryScreenModel(
     suspend fun getRandomLibraryItemForCurrentCategory(): LibraryItem? {
         return withIOContext {
             state.value
-                .getLibraryItemsByCategoryId(activeCategory.toLong())
+                .getLibraryItemsByCategoryId(state.value.categories[activeCategoryIndex].id)
                 ?.randomOrNull()
         }
     }

app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryTab.kt

@@ -97,7 +97,7 @@ object LibraryTab : Tab {
             started
         }
         val onClickFilter: () -> Unit = {
-            scope.launch { sendSettingsSheetIntent(state.categories[screenModel.activeCategory]) }
+            scope.launch { sendSettingsSheetIntent(state.categories[screenModel.activeCategoryIndex]) }
         }
 
         Scaffold(
@@ -105,7 +105,7 @@ object LibraryTab : Tab {
                 val title = state.getToolbarTitle(
                     defaultTitle = stringResource(R.string.label_library),
                     defaultCategoryTitle = stringResource(R.string.label_default),
-                    page = screenModel.activeCategory,
+                    page = screenModel.activeCategoryIndex,
                 )
                 val tabVisible = state.showCategoryTabs && state.categories.size > 1
                 LibraryToolbar(
@@ -115,8 +115,8 @@ object LibraryTab : Tab {
                     incognitoMode = !tabVisible && screenModel.isIncognitoMode,
                     downloadedOnlyMode = !tabVisible && screenModel.isDownloadOnly,
                     onClickUnselectAll = screenModel::clearSelection,
-                    onClickSelectAll = { screenModel.selectAll(screenModel.activeCategory) },
-                    onClickInvertSelection = { screenModel.invertSelection(screenModel.activeCategory) },
+                    onClickSelectAll = { screenModel.selectAll(screenModel.activeCategoryIndex) },
+                    onClickInvertSelection = { screenModel.invertSelection(screenModel.activeCategoryIndex) },
                     onClickFilter = onClickFilter,
                     onClickRefresh = { onClickRefresh(null) },
                     onClickOpenRandomManga = {
@@ -169,9 +169,9 @@ object LibraryTab : Tab {
                         searchQuery = state.searchQuery,
                         selection = state.selection,
                         contentPadding = contentPadding,
-                        currentPage = { screenModel.activeCategory },
+                        currentPage = { screenModel.activeCategoryIndex },
                         showPageTabs = state.showCategoryTabs || !state.searchQuery.isNullOrEmpty(),
-                        onChangeCurrentPage = { screenModel.activeCategory = it },
+                        onChangeCurrentPage = { screenModel.activeCategoryIndex = it },
                         onMangaClicked = { navigator.push(MangaScreen(it)) },
                         onContinueReadingClicked = { it: LibraryManga ->
                             scope.launchIO {