fix: run dart fix

lib/api/library_provider.dart

@@ -26,7 +26,7 @@ Future<Library?> library(Ref ref, String id) async {
     _logger.warning('No library found in the list of libraries');
     return null;
   }
-  _logger.fine('Fetched library: ${library}');
+  _logger.fine('Fetched library: $library');
   return library.library;
 }
 

lib/api/library_provider.g.dart

@@ -6,7 +6,7 @@ part of 'library_provider.dart';
 // RiverpodGenerator
 // **************************************************************************
 
-String _$libraryHash() => r'b62d976f8ab83b2f5823a0fb7dac52fde8fcbffc';
+String _$libraryHash() => r'f8a34100acb58f02fa958c71a629577bf815710e';
 
 /// Copied from Dart SDK
 class _SystemHash {

lib/features/item_viewer/view/library_item_page.dart

@@ -3,6 +3,7 @@ import 'dart:math';
 import 'package:animated_theme_switcher/animated_theme_switcher.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_animate/flutter_animate.dart';
+import 'package:flutter_hooks/flutter_hooks.dart';
 import 'package:hooks_riverpod/hooks_riverpod.dart';
 import 'package:vaani/api/library_item_provider.dart';
 import 'package:vaani/features/item_viewer/view/library_item_sliver_app_bar.dart';
@@ -23,19 +24,89 @@ class LibraryItemPage extends HookConsumerWidget {
 
   final String itemId;
   final Object? extra;
+  static const double _showFabThreshold = 300.0;
   @override
   Widget build(BuildContext context, WidgetRef ref) {
     final additionalItemData =
         extra is LibraryItemExtras ? extra as LibraryItemExtras : null;
+    final scrollController = useScrollController();
+    final showFab = useState(false);
+
+    // Effect to listen to scroll changes and update FAB visibility
+    useEffect(
+      () {
+        void listener() {
+          if (!scrollController.hasClients) {
+            return; // Ensure controller is attached
+          }
+          final shouldShow = scrollController.offset > _showFabThreshold;
+          // Update state only if it changes and widget is still mounted
+          if (showFab.value != shouldShow && context.mounted) {
+            showFab.value = shouldShow;
+          }
+        }
+
+        scrollController.addListener(listener);
+        // Initial check in case the view starts scrolled (less likely but safe)
+        WidgetsBinding.instance.addPostFrameCallback((_) {
+          if (scrollController.hasClients && context.mounted) {
+            listener();
+          }
+        });
+
+        // Cleanup: remove the listener when the widget is disposed
+        return () => scrollController.removeListener(listener);
+      },
+      [scrollController],
+    ); // Re-run effect if scrollController changes
+
+    // --- FAB Scroll-to-Top Logic ---
+    void scrollToTop() {
+      if (scrollController.hasClients) {
+        scrollController.animateTo(
+          0.0, // Target offset (top)
+          duration: 300.ms,
+          curve: Curves.easeInOut,
+        );
+      }
+    }
 
     return ThemeProvider(
       initTheme: Theme.of(context),
       duration: 200.ms,
       child: ThemeSwitchingArea(
         child: Scaffold(
+          floatingActionButton: AnimatedSwitcher(
+            duration: 250.ms,
+            // A common transition for FABs (fade + scale)
+            transitionBuilder: (Widget child, Animation<double> animation) {
+              return ScaleTransition(
+                scale: animation,
+                child: FadeTransition(
+                  opacity: animation,
+                  child: child,
+                ),
+              );
+            },
+            child: showFab.value
+                ? FloatingActionButton(
+                    // Key is important for AnimatedSwitcher to differentiate
+                    key: const ValueKey('fab-scroll-top'),
+                    onPressed: scrollToTop,
+                    tooltip: 'Scroll to top',
+                    child: const Icon(Icons.arrow_upward),
+                  )
+                : const SizedBox.shrink(
+                    key: ValueKey('fab-empty'),
+                  ),
+          ),
           body: CustomScrollView(
+            controller: scrollController,
             slivers: [
-              const LibraryItemSliverAppBar(),
+              LibraryItemSliverAppBar(
+                id: itemId,
+                scrollController: scrollController,
+              ),
               SliverPadding(
                 padding: const EdgeInsets.all(8),
                 sliver: LibraryItemHeroSection(

lib/features/item_viewer/view/library_item_sliver_app_bar.dart

@@ -1,22 +1,80 @@
 import 'package:flutter/material.dart';
+import 'package:flutter_hooks/flutter_hooks.dart';
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+import 'package:vaani/api/library_item_provider.dart' show libraryItemProvider;
 
-class LibraryItemSliverAppBar extends StatelessWidget {
+class LibraryItemSliverAppBar extends HookConsumerWidget {
   const LibraryItemSliverAppBar({
     super.key,
+    required this.id,
+    required this.scrollController,
   });
 
+  final String id;
+  final ScrollController scrollController;
+
+  static const double _showTitleThreshold = kToolbarHeight * 0.5;
+
   @override
-  Widget build(BuildContext context) {
+  Widget build(BuildContext context, WidgetRef ref) {
+    final item = ref.watch(libraryItemProvider(id)).valueOrNull;
+
+    final showTitle = useState(false);
+
+    useEffect(
+      () {
+        void listener() {
+          final shouldShow = scrollController.hasClients &&
+              scrollController.offset > _showTitleThreshold;
+          if (showTitle.value != shouldShow) {
+            showTitle.value = shouldShow;
+          }
+        }
+
+        scrollController.addListener(listener);
+        // Trigger listener once initially in case the view starts scrolled
+        // (though unlikely for this specific use case, it's good practice)
+        WidgetsBinding.instance.addPostFrameCallback((_) {
+          if (scrollController.hasClients) {
+            listener();
+          }
+        });
+        return () => scrollController.removeListener(listener);
+      },
+      [scrollController],
+    );
+
     return SliverAppBar(
       elevation: 0,
-      floating: true,
+      floating: false,
+      pinned: true,
       primary: true,
-      snap: true,
       actions: [
-        // cast button
+        // IconButton(
-        IconButton(onPressed: () {}, icon: const Icon(Icons.cast)),
+        //   icon: const Icon(Icons.cast),
-        IconButton(onPressed: () {}, icon: const Icon(Icons.more_vert)),
+        //   onPressed: () {
+        //     // Handle search action
+        //   },
+        // ),
       ],
+      title: AnimatedSwitcher(
+        duration: const Duration(milliseconds: 150),
+        child: showTitle.value
+            ? Text(
+                // Use a Key to help AnimatedSwitcher differentiate widgets
+                key: const ValueKey('title-text'),
+                item?.media.metadata.title ?? '',
+                overflow: TextOverflow.ellipsis,
+                style: Theme.of(context).textTheme.bodyMedium,
+              )
+            : const SizedBox(
+                // Also give it a key for differentiation
+                key: ValueKey('empty-title'),
+                width: 0, // Ensure it takes no space if possible
+                height: 0,
+              ),
+      ),
+      centerTitle: false,
     );
   }
 }

lib/features/you/view/widgets/library_switch_chip.dart

@@ -204,7 +204,8 @@ class _LibrarySelectionContent extends ConsumerWidget {
                 trailing: isSelected ? const Icon(Icons.check) : null,
                 onTap: () {
                   appLogger.info(
-                      'Selected library: ${library.name} (ID: ${library.id})');
+                    'Selected library: ${library.name} (ID: ${library.id})',
+                  );
                   // Get current settings state
                   final currentSettings = ref.read(apiSettingsProvider);
                   // Update the active library ID