fix: bootstrap defaults and refine shared collection actions

lib/main.dart

@@ -1,7 +1,9 @@
 import 'package:flutter/material.dart';
+import 'package:shared_preferences/shared_preferences.dart';
 import 'package:supabase_flutter/supabase_flutter.dart';
 import 'theme/app_theme.dart';
 import 'services/collection_service.dart';
+import 'services/main_collection_sync.dart';
 import 'screens/login_screen.dart';
 import 'screens/home_shell.dart';
 
@@ -88,6 +90,8 @@ class AuthGate extends StatefulWidget {
 }
 
 class _AuthGateState extends State<AuthGate> {
+  static const _activeCollectionPrefKey = 'active_collection_id';
+
   bool _isLoading = true;
   bool _isInPasswordRecoveryFlow = false;
   Session? _session;
@@ -133,12 +137,57 @@ class _AuthGateState extends State<AuthGate> {
 
     _lastEnsuredUserId = userId;
     try {
-      await CollectionService.ensureDefaultCollection();
+      final defaultCollectionId = await CollectionService.ensureDefaultCollection();
+      await _ensureMainCollectionPreference(defaultCollectionId);
     } catch (e) {
       showGlobalSnackBar('Collection setup failed: $e', isError: true);
     }
   }
 
+  Future<void> _ensureMainCollectionPreference(String? defaultCollectionId) async {
+    final userId = _session?.user.id;
+    if (userId == null) return;
+
+    final prefs = await SharedPreferences.getInstance();
+    final persisted = prefs.getString(_activeCollectionPrefKey);
+
+    Future<bool> hasMembership(String collectionId) async {
+      final membership = await supabase
+          .from('collection_members')
+          .select('id')
+          .eq('user_id', userId)
+          .eq('collection_id', collectionId)
+          .maybeSingle();
+      return membership != null;
+    }
+
+    if (persisted != null && await hasMembership(persisted)) {
+      return;
+    }
+
+    String? nextActiveId;
+    if (defaultCollectionId != null && await hasMembership(defaultCollectionId)) {
+      nextActiveId = defaultCollectionId;
+    } else {
+      final firstMembership = await supabase
+          .from('collection_members')
+          .select('collection_id')
+          .eq('user_id', userId)
+          .limit(1);
+      if (firstMembership.isNotEmpty) {
+        nextActiveId = firstMembership.first['collection_id'] as String;
+      }
+    }
+
+    if (nextActiveId == null) {
+      await prefs.remove(_activeCollectionPrefKey);
+      return;
+    }
+
+    await prefs.setString(_activeCollectionPrefKey, nextActiveId);
+    MainCollectionSync.notifyChanged();
+  }
+
   Future<void> _showResetPasswordDialog() async {
     await showDialog<void>(
       context: navigatorKey.currentContext!,

lib/screens/collections_screen.dart

@@ -15,23 +15,45 @@ class CollectionsScreen extends StatefulWidget {
   State<CollectionsScreen> createState() => CollectionsScreenState();
 }
 
-class CollectionsScreenState extends State<CollectionsScreen> {
+class CollectionsScreenState extends State<CollectionsScreen>
+  with WidgetsBindingObserver {
   static const _activeCollectionPrefKey = 'active_collection_id';
 
   List<Collection> _collections = [];
   bool _isLoading = true;
   String? _error;
   String? _activeCollectionId;
+  DateTime _lastLoadedAt = DateTime.fromMillisecondsSinceEpoch(0);
 
   @override
   void initState() {
     super.initState();
+    WidgetsBinding.instance.addObserver(this);
     _load();
   }
 
+  @override
+  void dispose() {
+    WidgetsBinding.instance.removeObserver(this);
+    super.dispose();
+  }
+
+  @override
+  void didChangeAppLifecycleState(AppLifecycleState state) {
+    if (state == AppLifecycleState.resumed) {
+      refreshIfStale(maxAge: const Duration(seconds: 3));
+    }
+  }
+
   /// Public so other tabs can trigger a refresh.
   void refresh() => _load();
 
+  void refreshIfStale({Duration maxAge = const Duration(seconds: 10)}) {
+    if (DateTime.now().difference(_lastLoadedAt) > maxAge) {
+      _load();
+    }
+  }
+
   Future<void> _load() async {
     setState(() {
       _isLoading = true;
@@ -44,19 +66,28 @@ class CollectionsScreenState extends State<CollectionsScreen> {
       final persisted = prefs.getString(_activeCollectionPrefKey);
 
       String? activeId = persisted;
+      if (activeId == null && list.isNotEmpty) {
+        activeId = list.first.id;
+      }
       if (activeId != null && !list.any((c) => c.id == activeId)) {
         activeId = list.isNotEmpty ? list.first.id : null;
       }
 
+      final shouldNotifySync = activeId != null && activeId != persisted;
+
       if (!mounted) return;
       setState(() {
         _collections = list;
         _activeCollectionId = activeId;
         _isLoading = false;
+        _lastLoadedAt = DateTime.now();
       });
 
       if (activeId != null) {
         await prefs.setString(_activeCollectionPrefKey, activeId);
+        if (shouldNotifySync) {
+          MainCollectionSync.notifyChanged();
+        }
       }
     } catch (e) {
       if (!mounted) return;
@@ -179,7 +210,9 @@ class CollectionsScreenState extends State<CollectionsScreen> {
   @override
   Widget build(BuildContext context) {
     return Scaffold(
-      body: CustomScrollView(
+      body: RefreshIndicator(
+        onRefresh: _load,
+        child: CustomScrollView(
         slivers: [
           // ── Header ──
           SliverAppBar(
@@ -322,6 +355,7 @@ class CollectionsScreenState extends State<CollectionsScreen> {
             ),
           ],
         ),
+      ),
       floatingActionButton: _collections.isNotEmpty
           ? FloatingActionButton(
               onPressed: _createCollection,

lib/screens/garage_screen.dart

@@ -346,8 +346,9 @@ class GarageScreenState extends State<GarageScreen> {
                       ),
                     ),
                     OutlinedButton(
-                      onPressed: _selectedIds.isEmpty ? null : _moveSelectedCars,
+                      onPressed:
-                      child: const Text('Move to...'),
+                          _selectedIds.isEmpty ? null : _relocateSelectedCars,
+                      child: Text(widget.isOwner ? 'Move to...' : 'Copy to...'),
                     ),
                   ],
                 ),
@@ -392,10 +393,11 @@ class GarageScreenState extends State<GarageScreen> {
     });
   }
 
-  Future<void> _moveSelectedCars() async {
+  Future<void> _relocateSelectedCars() async {
     if (_selectedIds.isEmpty) return;
 
     try {
+      final isOwner = widget.isOwner;
       final collections = await CollectionService.getMyCollections();
       if (!mounted) return;
 
@@ -413,7 +415,7 @@ class GarageScreenState extends State<GarageScreen> {
         context: context,
         builder: (_) => StatefulBuilder(
           builder: (context, setSheetState) => AlertDialog(
-            title: const Text('Move Selected Cars'),
+            title: Text(isOwner ? 'Move Selected Cars' : 'Copy Selected Cars'),
             content: DropdownButtonFormField<String>(
               initialValue: targetId,
               decoration: const InputDecoration(
@@ -438,7 +440,7 @@ class GarageScreenState extends State<GarageScreen> {
                 onPressed: targetId == null
                     ? null
                     : () => Navigator.pop(context, true),
-                child: const Text('Move'),
+                child: Text(isOwner ? 'Move' : 'Copy'),
               ),
             ],
           ),
@@ -447,17 +449,47 @@ class GarageScreenState extends State<GarageScreen> {
 
       if (confirmed != true || targetId == null) return;
 
+      if (isOwner) {
         await supabase
             .from('hotwheels')
             .update({'collection_id': targetId})
             .inFilter('id', _selectedIds.toList());
+      } else {
+        final sourceCars = _cars
+            .where((car) => _selectedIds.contains(car['id'] as int))
+            .toList(growable: false);
+
+        final insertRows = sourceCars.map((car) {
+          final notes = car['notes'] as String?;
+          final imagePath = car['user_image_url'] as String?;
+          return <String, dynamic>{
+            'hw_id': car['hw_id'] as String,
+            'user_id': supabase.auth.currentUser!.id,
+            'collection_id': targetId,
+            if (notes != null && notes.trim().isNotEmpty) 'notes': notes,
+            if (imagePath != null && imagePath.isNotEmpty)
+              'user_image_url': imagePath,
+          };
+        }).toList(growable: false);
+
+        if (insertRows.isNotEmpty) {
+          await supabase.from('hotwheels').insert(insertRows);
+        }
+      }
 
       if (!mounted) return;
-      showGlobalSnackBar('${_selectedIds.length} car(s) moved.');
+      showGlobalSnackBar(
+        isOwner
+            ? '${_selectedIds.length} car(s) moved.'
+            : '${_selectedIds.length} car(s) copied.',
+      );
       _toggleSelectionMode(false);
       await _loadCars(reset: true);
     } catch (e) {
-      showGlobalSnackBar('Failed to move cars: $e', isError: true);
+      showGlobalSnackBar(
+        widget.isOwner ? 'Failed to move cars: $e' : 'Failed to copy cars: $e',
+        isError: true,
+      );
     }
   }
 

lib/screens/home_shell.dart

@@ -12,11 +12,10 @@ class HomeShell extends StatefulWidget {
 }
 
 class _HomeShellState extends State<HomeShell> {
-  static const double _swipeVelocityThreshold = 300;
-
   int _currentIndex = 0;
   final _collectionsKey = GlobalKey<CollectionsScreenState>();
   final _scanKey = GlobalKey<ScanTabState>();
+  late final PageController _pageController;
 
   late final List<Widget> _pages = <Widget>[
     CollectionsScreen(key: _collectionsKey),
@@ -24,35 +23,46 @@ class _HomeShellState extends State<HomeShell> {
     const ProfileScreen(),
   ];
 
+  @override
+  void initState() {
+    super.initState();
+    _pageController = PageController(initialPage: _currentIndex);
+  }
+
+  @override
+  void dispose() {
+    _pageController.dispose();
+    super.dispose();
+  }
+
   void _onTabSelected(int i) {
+    if (_currentIndex == i) return;
     setState(() => _currentIndex = i);
-  }
+    _pageController.animateToPage(
-
+      i,
-  void _handleHorizontalSwipe(DragEndDetails details) {
+      duration: const Duration(milliseconds: 260),
-    final velocity = details.primaryVelocity ?? 0;
+      curve: Curves.easeOutCubic,
-    if (velocity.abs() < _swipeVelocityThreshold) return;
+    );
-
+    if (i == 0) {
-    if (velocity < 0 && _currentIndex < _pages.length - 1) {
+      _collectionsKey.currentState?.refreshIfStale();
-      _onTabSelected(_currentIndex + 1);
-      return;
-    }
-
-    if (velocity > 0 && _currentIndex > 0) {
-      _onTabSelected(_currentIndex - 1);
     }
   }
 
   @override
   Widget build(BuildContext context) {
     return Scaffold(
-      body: GestureDetector(
+      body: PageView(
-        behavior: HitTestBehavior.translucent,
+        controller: _pageController,
-        onHorizontalDragEnd: _handleHorizontalSwipe,
+        onPageChanged: (index) {
-        child: IndexedStack(
+          if (_currentIndex != index) {
-          index: _currentIndex,
+            setState(() => _currentIndex = index);
+          }
+          if (index == 0) {
+            _collectionsKey.currentState?.refreshIfStale();
+          }
+        },
         children: _pages,
       ),
-      ),
       bottomNavigationBar: NavigationBar(
         selectedIndex: _currentIndex,
         onDestinationSelected: _onTabSelected,

lib/services/collection_service.dart

@@ -51,22 +51,26 @@ class CollectionService {
 
   /// Ensures the current user has at least one collection membership.
   /// Creates a default collection on first login.
-  static Future<void> ensureDefaultCollection() async {
+  static Future<String?> ensureDefaultCollection() async {
     final userId = supabase.auth.currentUser?.id;
-    if (userId == null) return;
+    if (userId == null) return null;
 
     final existing = await supabase
         .from('collection_members')
-        .select('id')
+        .select('collection_id')
         .eq('user_id', userId)
         .limit(1);
 
-    if (existing.isNotEmpty) return;
+    if (existing.isNotEmpty) {
+      return existing.first['collection_id'] as String;
+    }
 
-    await create(
+    final created = await create(
       name: 'My Garage',
       description: 'Your default collection',
     );
+
+    return created.id;
   }
 
   /// Fetch all collections the current user is a member of,

lib/services/storage_service.dart

@@ -15,6 +15,7 @@ class StorageService {
   static const int _maxImageBytes = 500 * 1024;
   static const int _maxWidth = 1080;
   static const int _signedUrlExpirySeconds = 3600;
+  static const int _maxCompressionAttempts = 5;
   static const _signedUrlRefreshBuffer = Duration(minutes: 3);
   static const _maxSignedUrlCacheEntries = 500;
   static final Map<String, _SignedUrlCacheEntry> _signedUrlCache = {};
@@ -114,19 +115,26 @@ class StorageService {
         : decoded;
 
     var quality = 85;
+    var attempts = 0;
     Uint8List out = Uint8List.fromList(img.encodeJpg(working, quality: quality));
 
     // First pass: reduce JPEG quality.
-    while (out.lengthInBytes > _maxImageBytes && quality > 35) {
+    while (out.lengthInBytes > _maxImageBytes &&
+        quality > 35 &&
+        attempts < _maxCompressionAttempts) {
       quality -= 5;
       out = Uint8List.fromList(img.encodeJpg(working, quality: quality));
+      attempts += 1;
     }
 
     // Second pass: reduce dimensions progressively if still above the limit.
-    while (out.lengthInBytes > _maxImageBytes && working.width > 320) {
+    while (out.lengthInBytes > _maxImageBytes &&
+        working.width > 320 &&
+        attempts < _maxCompressionAttempts) {
       final nextWidth = (working.width * 0.85).round();
       working = img.copyResize(working, width: nextWidth);
       out = Uint8List.fromList(img.encodeJpg(working, quality: quality));
+      attempts += 1;
     }
 
     if (out.lengthInBytes > _maxImageBytes) {