added categories, import export, settings

lib/home_shell.dart

@@ -0,0 +1,108 @@
+/// Bottom navigation: products, scan, and shop log.
+library;
+
+import 'package:flutter/material.dart';
+
+import 'products_screen.dart';
+import 'scan_screen.dart';
+import 'services/app_settings.dart';
+import 'services/product_repository.dart';
+import 'shop_log_screen.dart';
+
+class HomeShell extends StatefulWidget {
+  const HomeShell({super.key, required this.repository});
+
+  final ProductRepository repository;
+
+  @override
+  State<HomeShell> createState() => _HomeShellState();
+}
+
+class _HomeShellState extends State<HomeShell> {
+  static const _scanIndex = 1;
+  static const _shopLogIndex = 2;
+
+  int _index = _scanIndex;
+  int _revision = 0;
+  AppSettings? _settings;
+  int _seenGeneration = 0;
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    final settings = SettingsScope.maybeOf(context);
+    if (settings != _settings) {
+      _settings?.removeListener(_onSettings);
+      _settings = settings;
+      _seenGeneration = settings?.catalogGeneration ?? 0;
+      _settings?.addListener(_onSettings);
+    }
+  }
+
+  @override
+  void dispose() {
+    _settings?.removeListener(_onSettings);
+    super.dispose();
+  }
+
+  void _onSettings() {
+    final generation = _settings?.catalogGeneration ?? 0;
+    if (generation == _seenGeneration) return;
+    _seenGeneration = generation;
+    if (mounted) setState(() => _revision++);
+  }
+
+  void _onTripSaved() {
+    setState(() {
+      _index = _shopLogIndex;
+      _revision++;
+    });
+    WidgetsBinding.instance.addPostFrameCallback((_) {
+      if (!mounted) return;
+      ScaffoldMessenger.of(context).showSnackBar(
+        const SnackBar(content: Text('Shopping trip saved.')),
+      );
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      body: switch (_index) {
+        0 => ProductsScreen(
+            key: ValueKey('products-$_revision'),
+            repository: widget.repository,
+          ),
+        1 => ScanScreen(
+            repository: widget.repository,
+            onTripSaved: _onTripSaved,
+          ),
+        _ => ShopLogScreen(
+            key: ValueKey('shops-$_revision'),
+            repository: widget.repository,
+          ),
+      },
+      bottomNavigationBar: NavigationBar(
+        selectedIndex: _index,
+        onDestinationSelected: (index) => setState(() => _index = index),
+        destinations: const [
+          NavigationDestination(
+            icon: Icon(Icons.inventory_2_outlined),
+            selectedIcon: Icon(Icons.inventory_2),
+            label: 'Products',
+          ),
+          NavigationDestination(
+            icon: Icon(Icons.photo_camera_outlined),
+            selectedIcon: Icon(Icons.photo_camera),
+            label: 'Scan',
+          ),
+          NavigationDestination(
+            icon: Icon(Icons.receipt_long_outlined),
+            selectedIcon: Icon(Icons.receipt_long),
+            label: 'Shop log',
+          ),
+        ],
+      ),
+    );
+  }
+}

lib/main.dart

@@ -3,7 +3,8 @@ library;
 
 import 'package:flutter/material.dart';
 
-import 'scan_screen.dart';
+import 'home_shell.dart';
+import 'services/app_settings.dart';
 import 'services/product_repository.dart';
 import 'utils/app_theme.dart';
 import 'utils/constants.dart';
@@ -13,20 +14,48 @@ void main() {
   runApp(ReceipityApp());
 }
 
-class ReceipityApp extends StatelessWidget {
+class ReceipityApp extends StatefulWidget {
   ReceipityApp({super.key, ProductRepository? repository})
       : repository = repository ?? ProductRepository();
 
   final ProductRepository repository;
 
+  @override
+  State<ReceipityApp> createState() => _ReceipityAppState();
+}
+
+class _ReceipityAppState extends State<ReceipityApp> {
+  late final AppSettings _settings;
+
+  @override
+  void initState() {
+    super.initState();
+    _settings = AppSettings(widget.repository);
+    _settings.addListener(_onSettings);
+    _settings.load();
+  }
+
+  @override
+  void dispose() {
+    _settings.removeListener(_onSettings);
+    _settings.dispose();
+    super.dispose();
+  }
+
+  void _onSettings() => setState(() {});
+
   @override
   Widget build(BuildContext context) {
-    return MaterialApp(
-      title: kAppName,
-      debugShowCheckedModeBanner: false,
-      theme: AppTheme.light(),
-      darkTheme: AppTheme.dark(),
-      home: ScanScreen(repository: repository),
+    return SettingsScope(
+      settings: _settings,
+      child: MaterialApp(
+        title: kAppName,
+        debugShowCheckedModeBanner: false,
+        theme: AppTheme.light(),
+        darkTheme: AppTheme.dark(),
+        themeMode: _settings.darkMode ? ThemeMode.dark : ThemeMode.light,
+        home: HomeShell(repository: widget.repository),
+      ),
     );
   }
 }

lib/models/product.dart

@@ -8,6 +8,11 @@ class Product {
     required this.lastPrice,
     required this.timesSeen,
     required this.updatedAt,
+    this.favourite = false,
+    this.imagePath,
+    this.supermarket,
+    this.notes,
+    this.category,
   });
 
   final int id;
@@ -15,14 +20,56 @@ class Product {
   final double lastPrice;
   final int timesSeen;
   final DateTime updatedAt;
+  final bool favourite;
+  final String? imagePath;
+  final String? supermarket;
+  final String? notes;
+  final String? category;
 
   factory Product.fromMap(Map<String, Object?> map) {
     return Product(
       id: map['id']! as int,
       name: map['name']! as String,
-      lastPrice: (map['last_price']! as num).toDouble(),
+      lastPrice: (map['display_price'] as num? ?? map['last_price']! as num)
+          .toDouble(),
       timesSeen: map['times_seen']! as int,
       updatedAt: DateTime.parse(map['updated_at']! as String),
+      favourite: (map['favourite'] as int? ?? 0) == 1,
+      imagePath: map['image_path'] as String?,
+      supermarket: map['supermarket'] as String?,
+      notes: map['notes'] as String?,
+      category: map['category'] as String?,
+    );
+  }
+
+  Product copyWith({
+    String? name,
+    double? lastPrice,
+    int? timesSeen,
+    DateTime? updatedAt,
+    bool? favourite,
+    String? imagePath,
+    String? supermarket,
+    String? notes,
+    String? category,
+    bool clearImage = false,
+    bool clearSupermarket = false,
+    bool clearNotes = false,
+    bool clearCategory = false,
+  }) {
+    return Product(
+      id: id,
+      name: name ?? this.name,
+      lastPrice: lastPrice ?? this.lastPrice,
+      timesSeen: timesSeen ?? this.timesSeen,
+      updatedAt: updatedAt ?? this.updatedAt,
+      favourite: favourite ?? this.favourite,
+      imagePath: clearImage ? null : (imagePath ?? this.imagePath),
+      supermarket: clearSupermarket ? null : (supermarket ?? this.supermarket),
+      notes: clearNotes ? null : (notes ?? this.notes),
+      category: clearCategory ? null : (category ?? this.category),
     );
   }
 }
+
+enum ProductSort { name, preferred }

lib/models/purchase.dart

@@ -0,0 +1,36 @@
+/// One time a product was bought, used for price and purchase history.
+library;
+
+class Purchase {
+  const Purchase({
+    required this.shopId,
+    required this.boughtAt,
+    required this.supermarket,
+    required this.price,
+    this.quantity,
+    this.unitPrice,
+    this.receiptImagePath,
+  });
+
+  final int shopId;
+  final DateTime boughtAt;
+  final String supermarket;
+  final double price;
+  final int? quantity;
+  final double? unitPrice;
+  final String? receiptImagePath;
+
+  double get unitOrLinePrice => unitPrice ?? price;
+
+  factory Purchase.fromMap(Map<String, Object?> map) {
+    return Purchase(
+      shopId: map['shop_id']! as int,
+      boughtAt: DateTime.parse(map['shopped_at']! as String),
+      supermarket: map['supermarket']! as String,
+      price: (map['price']! as num).toDouble(),
+      quantity: map['quantity'] as int?,
+      unitPrice: (map['unit_price'] as num?)?.toDouble(),
+      receiptImagePath: map['receipt_image_path'] as String?,
+    );
+  }
+}

lib/models/shop.dart

@@ -0,0 +1,63 @@
+/// A confirmed shopping trip saved from a receipt.
+library;
+
+class Shop {
+  const Shop({
+    required this.id,
+    required this.supermarket,
+    required this.shoppedAt,
+    required this.total,
+    required this.itemCount,
+    this.receiptImagePath,
+  });
+
+  final int id;
+  final String supermarket;
+  final DateTime shoppedAt;
+  final double total;
+  final int itemCount;
+  final String? receiptImagePath;
+
+  factory Shop.fromMap(Map<String, Object?> map) {
+    return Shop(
+      id: map['id']! as int,
+      supermarket: map['supermarket']! as String,
+      shoppedAt: DateTime.parse(map['shopped_at']! as String),
+      total: (map['total']! as num).toDouble(),
+      itemCount: (map['item_count'] as num?)?.toInt() ?? 0,
+      receiptImagePath: map['receipt_image_path'] as String?,
+    );
+  }
+}
+
+class ShopItem {
+  const ShopItem({
+    required this.id,
+    required this.shopId,
+    required this.productId,
+    required this.name,
+    required this.price,
+    this.quantity,
+    this.unitPrice,
+  });
+
+  final int id;
+  final int shopId;
+  final int productId;
+  final String name;
+  final double price;
+  final int? quantity;
+  final double? unitPrice;
+
+  factory ShopItem.fromMap(Map<String, Object?> map) {
+    return ShopItem(
+      id: map['id']! as int,
+      shopId: map['shop_id']! as int,
+      productId: map['product_id']! as int,
+      name: map['name']! as String,
+      price: (map['price']! as num).toDouble(),
+      quantity: map['quantity'] as int?,
+      unitPrice: (map['unit_price'] as num?)?.toDouble(),
+    );
+  }
+}

lib/models/supermarket.dart

@@ -0,0 +1,59 @@
+/// A user-defined supermarket with a display color.
+library;
+
+import 'package:flutter/material.dart';
+
+class Supermarket {
+  const Supermarket({
+    this.id,
+    required this.name,
+    required this.colorValue,
+    this.sortOrder = 0,
+  });
+
+  final int? id;
+  final String name;
+  final int colorValue;
+  final int sortOrder;
+
+  Color get color => Color(colorValue);
+
+  factory Supermarket.fromMap(Map<String, Object?> map) {
+    return Supermarket(
+      id: map['id'] as int?,
+      name: map['name']! as String,
+      colorValue: map['color']! as int,
+      sortOrder: map['sort_order'] as int? ?? 0,
+    );
+  }
+
+  Supermarket copyWith({
+    int? id,
+    String? name,
+    int? colorValue,
+    int? sortOrder,
+  }) {
+    return Supermarket(
+      id: id ?? this.id,
+      name: name ?? this.name,
+      colorValue: colorValue ?? this.colorValue,
+      sortOrder: sortOrder ?? this.sortOrder,
+    );
+  }
+}
+
+/// Palette offered when the user picks a store color.
+const List<int> kStoreColorPalette = [
+  0xFFEEC21B, // Jumbo yellow
+  0xFF0050AA, // Lidl blue
+  0xFF00A0E2, // AH blue
+  0xFF00205B, // Aldi navy
+  0xFF6EC31E, // Plus green
+  0xFFE30613, // Dirk / Coop red
+  0xFF009640, // SPAR green
+  0xFFE87722, // orange
+  0xFFE31C5F, // Picnic pink
+  0xFF7B1FA2, // purple
+  0xFF00897B, // teal
+  0xFF78909C, // grey
+];

lib/product_detail_screen.dart

@@ -0,0 +1,487 @@
+/// Product: photo, name, favourite, price history chart, and notes.
+library;
+
+import 'package:flutter/material.dart';
+import 'package:image_picker/image_picker.dart';
+
+import 'models/product.dart';
+import 'models/purchase.dart';
+import 'services/app_settings.dart';
+import 'services/product_repository.dart';
+import 'shop_detail_screen.dart';
+import 'utils/categories.dart';
+import 'utils/dates.dart';
+import 'utils/money.dart';
+import 'utils/supermarkets.dart';
+import 'widgets/price_chart.dart';
+import 'widgets/product_image.dart';
+import 'widgets/store_tag.dart';
+
+class ProductDetailScreen extends StatefulWidget {
+  const ProductDetailScreen({
+    super.key,
+    required this.repository,
+    required this.productId,
+  });
+
+  final ProductRepository repository;
+  final int productId;
+
+  @override
+  State<ProductDetailScreen> createState() => _ProductDetailScreenState();
+}
+
+class _ProductDetailScreenState extends State<ProductDetailScreen> {
+  late Future<({Product product, List<Purchase> purchases})> _future;
+  late final TextEditingController _nameController;
+  late final TextEditingController _notesController;
+  final ImagePicker _picker = ImagePicker();
+  bool _ready = false;
+
+  @override
+  void initState() {
+    super.initState();
+    _nameController = TextEditingController();
+    _notesController = TextEditingController();
+    _future = _load();
+  }
+
+  @override
+  void dispose() {
+    _saveNotes();
+    _nameController.dispose();
+    _notesController.dispose();
+    super.dispose();
+  }
+
+  Future<({Product product, List<Purchase> purchases})> _load() async {
+    final product = await widget.repository.getProduct(widget.productId);
+    if (product == null) {
+      throw StateError('Product not found');
+    }
+    final purchases = await widget.repository.getPurchases(widget.productId);
+    if (!_ready) {
+      _nameController.text = product.name;
+      _notesController.text = product.notes ?? '';
+      _ready = true;
+    }
+    return (product: product, purchases: purchases);
+  }
+
+  void _reload() {
+    setState(() => _future = _load());
+  }
+
+  Future<void> _saveName() async {
+    final name = _nameController.text.trim();
+    if (name.isEmpty) return;
+    await widget.repository.updateProduct(id: widget.productId, name: name);
+    if (mounted) _reload();
+  }
+
+  Future<void> _saveNotes() async {
+    await widget.repository.updateProduct(
+      id: widget.productId,
+      notes: _notesController.text.trim(),
+    );
+  }
+
+  Future<void> _toggleFavourite(Product product) async {
+    await widget.repository.setFavourite(product.id, !product.favourite);
+    if (mounted) _reload();
+  }
+
+  Future<void> _setSupermarket(String? value) async {
+    if (value == null) return;
+    await widget.repository.updateProduct(
+      id: widget.productId,
+      supermarket: value,
+    );
+    if (mounted) _reload();
+  }
+
+  Future<void> _pickImage(ImageSource source) async {
+    final file = await _picker.pickImage(source: source, imageQuality: 85);
+    if (file == null) return;
+    await widget.repository.setProductImage(widget.productId, file.path);
+    if (mounted) _reload();
+  }
+
+  Future<void> _chooseImageSource() async {
+    final source = await showModalBottomSheet<ImageSource>(
+      context: context,
+      showDragHandle: true,
+      builder: (context) {
+        return SafeArea(
+          child: Column(
+            mainAxisSize: MainAxisSize.min,
+            children: [
+              ListTile(
+                leading: const Icon(Icons.photo_camera_outlined),
+                title: const Text('Take photo'),
+                onTap: () => Navigator.pop(context, ImageSource.camera),
+              ),
+              ListTile(
+                leading: const Icon(Icons.photo_library_outlined),
+                title: const Text('Pick from gallery'),
+                onTap: () => Navigator.pop(context, ImageSource.gallery),
+              ),
+            ],
+          ),
+        );
+      },
+    );
+    if (source == null) return;
+    await _pickImage(source);
+  }
+
+  Future<void> _pickStore() async {
+    final settings = SettingsScope.maybeOf(context);
+    final stores = settings?.supermarkets ?? kDefaultSupermarkets;
+    final chosen = await showModalBottomSheet<String>(
+      context: context,
+      showDragHandle: true,
+      builder: (context) {
+        return SafeArea(
+          child: ListView(
+            shrinkWrap: true,
+            children: [
+              for (final store in stores)
+                ListTile(
+                  leading: StoreTag(name: store.name, stores: stores),
+                  title: Text(store.name),
+                  onTap: () => Navigator.pop(context, store.name),
+                ),
+            ],
+          ),
+        );
+      },
+    );
+    if (chosen != null) await _setSupermarket(chosen);
+  }
+
+  Future<void> _setCategory(String? value, {bool clear = false}) async {
+    await widget.repository.updateProduct(
+      id: widget.productId,
+      category: clear ? null : value,
+      clearCategory: clear,
+    );
+    if (mounted) _reload();
+  }
+
+  Future<void> _pickCategory(Product product) async {
+    final used = await widget.repository.getUsedCategories();
+    if (!mounted) return;
+    final categories = mergeCategories([
+      ...used,
+      if (product.category != null) product.category!,
+    ]);
+    final chosen = await showModalBottomSheet<String>(
+      context: context,
+      showDragHandle: true,
+      isScrollControlled: true,
+      builder: (context) {
+        return SafeArea(
+          child: ListView(
+            shrinkWrap: true,
+            children: [
+              ListTile(
+                leading: const Icon(Icons.clear),
+                title: const Text('No category'),
+                onTap: () => Navigator.pop(context, ''),
+              ),
+              for (final name in categories)
+                ListTile(
+                  leading: Icon(
+                    name == product.category
+                        ? Icons.check_circle
+                        : Icons.category_outlined,
+                  ),
+                  title: Text(name),
+                  onTap: () => Navigator.pop(context, name),
+                ),
+              ListTile(
+                leading: const Icon(Icons.add),
+                title: const Text('Custom category'),
+                onTap: () => Navigator.pop(context, '__custom__'),
+              ),
+            ],
+          ),
+        );
+      },
+    );
+    if (!mounted || chosen == null) return;
+    if (chosen.isEmpty) {
+      await _setCategory(null, clear: true);
+      return;
+    }
+    if (chosen == '__custom__') {
+      final custom = await _askCustomCategory(product.category);
+      if (custom == null || !mounted) return;
+      if (custom.isEmpty) {
+        await _setCategory(null, clear: true);
+      } else {
+        await _setCategory(custom);
+      }
+      return;
+    }
+    await _setCategory(chosen);
+  }
+
+  Future<String?> _askCustomCategory(String? current) async {
+    return showDialog<String>(
+      context: context,
+      builder: (context) => _CategoryNameDialog(initial: current),
+    );
+  }
+
+  Future<void> _openShop(int shopId) async {
+    await Navigator.of(context).push<void>(
+      MaterialPageRoute(
+        builder: (_) => ShopDetailScreen(
+          repository: widget.repository,
+          shopId: shopId,
+        ),
+      ),
+    );
+    if (mounted) _reload();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = Theme.of(context);
+    final stores = SettingsScope.maybeOf(context)?.supermarkets ??
+        kDefaultSupermarkets;
+
+    return Scaffold(
+      appBar: AppBar(title: const Text('Product')),
+      body: FutureBuilder(
+        future: _future,
+        builder: (context, snapshot) {
+          if (snapshot.hasError) {
+            return Center(
+              child: Text(
+                'Could not load this product.',
+                style: theme.textTheme.bodyLarge,
+              ),
+            );
+          }
+          if (!snapshot.hasData) {
+            return const Center(child: CircularProgressIndicator());
+          }
+
+          final product = snapshot.data!.product;
+          final purchases = snapshot.data!.purchases;
+
+          return ListView(
+            padding: const EdgeInsets.fromLTRB(16, 8, 16, 32),
+            children: [
+              Row(
+                crossAxisAlignment: CrossAxisAlignment.start,
+                children: [
+                  GestureDetector(
+                    onTap: _chooseImageSource,
+                    child: Stack(
+                      children: [
+                        ProductImage(
+                          name: product.name,
+                          path: product.imagePath,
+                          size: 88,
+                        ),
+                        Positioned(
+                          right: 0,
+                          bottom: 0,
+                          child: Material(
+                            color: theme.colorScheme.primary,
+                            shape: const CircleBorder(),
+                            child: Padding(
+                              padding: const EdgeInsets.all(4),
+                              child: Icon(
+                                Icons.camera_alt,
+                                size: 14,
+                                color: theme.colorScheme.onPrimary,
+                              ),
+                            ),
+                          ),
+                        ),
+                      ],
+                    ),
+                  ),
+                  const SizedBox(width: 12),
+                  Expanded(
+                    child: Column(
+                      crossAxisAlignment: CrossAxisAlignment.stretch,
+                      children: [
+                        Row(
+                          children: [
+                            Expanded(
+                              child: TextField(
+                                controller: _nameController,
+                                textCapitalization: TextCapitalization.sentences,
+                                decoration: const InputDecoration(
+                                  labelText: 'Name',
+                                  isDense: true,
+                                ),
+                                onSubmitted: (_) => _saveName(),
+                                onEditingComplete: _saveName,
+                              ),
+                            ),
+                            IconButton(
+                              tooltip: product.favourite
+                                  ? 'Remove favourite'
+                                  : 'Add favourite',
+                              onPressed: () => _toggleFavourite(product),
+                              icon: Icon(
+                                product.favourite
+                                    ? Icons.star
+                                    : Icons.star_outline,
+                                color: product.favourite
+                                    ? theme.colorScheme.primary
+                                    : null,
+                              ),
+                            ),
+                          ],
+                        ),
+                        const SizedBox(height: 8),
+                        Align(
+                          alignment: Alignment.centerLeft,
+                          child: InkWell(
+                            onTap: _pickStore,
+                            borderRadius: BorderRadius.circular(8),
+                            child: product.supermarket == null
+                                ? Text(
+                                    'Add supermarket',
+                                    style: theme.textTheme.labelMedium?.copyWith(
+                                      color: theme.colorScheme.primary,
+                                    ),
+                                  )
+                                : StoreTag(
+                                    name: product.supermarket,
+                                    stores: stores,
+                                  ),
+                          ),
+                        ),
+                      ],
+                    ),
+                  ),
+                ],
+              ),
+              const SizedBox(height: 24),
+              Text(
+                formatEuro(product.lastPrice),
+                style: theme.textTheme.headlineMedium,
+              ),
+              Text('Price per unit', style: theme.textTheme.bodyMedium),
+              const SizedBox(height: 12),
+              Align(
+                alignment: Alignment.centerLeft,
+                child: ActionChip(
+                  avatar: const Icon(Icons.category_outlined, size: 18),
+                  label: Text(product.category ?? 'Add category'),
+                  onPressed: () => _pickCategory(product),
+                ),
+              ),
+              const SizedBox(height: 24),
+              Text(
+                'Price and purchase history',
+                style: theme.textTheme.titleMedium,
+              ),
+              const SizedBox(height: 8),
+              if (purchases.isEmpty)
+                Text(
+                  'Scan a receipt to start a history.',
+                  style: theme.textTheme.bodyMedium,
+                )
+              else ...[
+                PriceChart(purchases: purchases),
+                const SizedBox(height: 8),
+                ...purchases.map((purchase) {
+                  return ListTile(
+                    contentPadding: EdgeInsets.zero,
+                    dense: true,
+                    leading: const Icon(Icons.shopping_bag_outlined),
+                    title: Text(formatEuro(purchase.unitOrLinePrice)),
+                    subtitle: Text(
+                      [
+                        formatDate(purchase.boughtAt),
+                        purchase.supermarket,
+                        if (purchase.quantity != null) '${purchase.quantity}×',
+                      ].join(' · '),
+                    ),
+                    trailing: const Icon(Icons.chevron_right),
+                    onTap: () => _openShop(purchase.shopId),
+                  );
+                }),
+              ],
+              const SizedBox(height: 24),
+              Text('Notes', style: theme.textTheme.titleMedium),
+              const SizedBox(height: 8),
+              TextField(
+                controller: _notesController,
+                minLines: 3,
+                maxLines: 6,
+                textCapitalization: TextCapitalization.sentences,
+                decoration: const InputDecoration(
+                  hintText: 'Add a note about this product',
+                ),
+                onEditingComplete: _saveNotes,
+                onTapOutside: (_) => _saveNotes(),
+              ),
+            ],
+          );
+        },
+      ),
+    );
+  }
+}
+
+class _CategoryNameDialog extends StatefulWidget {
+  const _CategoryNameDialog({this.initial});
+
+  final String? initial;
+
+  @override
+  State<_CategoryNameDialog> createState() => _CategoryNameDialogState();
+}
+
+class _CategoryNameDialogState extends State<_CategoryNameDialog> {
+  late final TextEditingController _controller;
+
+  @override
+  void initState() {
+    super.initState();
+    _controller = TextEditingController(text: widget.initial ?? '');
+  }
+
+  @override
+  void dispose() {
+    _controller.dispose();
+    super.dispose();
+  }
+
+  void _save() => Navigator.pop(context, _controller.text.trim());
+
+  @override
+  Widget build(BuildContext context) {
+    return AlertDialog(
+      title: const Text('Category'),
+      content: TextField(
+        controller: _controller,
+        textCapitalization: TextCapitalization.sentences,
+        autofocus: true,
+        decoration: const InputDecoration(labelText: 'Category'),
+        onSubmitted: (_) => _save(),
+      ),
+      actions: [
+        TextButton(
+          onPressed: () => Navigator.pop(context),
+          child: const Text('Cancel'),
+        ),
+        FilledButton(
+          onPressed: _save,
+          child: const Text('Save'),
+        ),
+      ],
+    );
+  }
+}

lib/products_screen.dart

@@ -1,100 +1,254 @@
-/// Confirmed products stored on device.
+/// Catalog of products from confirmed receipts.
 library;
 
 import 'package:flutter/material.dart';
 
 import 'models/product.dart';
+import 'product_detail_screen.dart';
+import 'services/app_settings.dart';
 import 'services/product_repository.dart';
+import 'utils/fuzzy.dart';
 import 'utils/money.dart';
+import 'widgets/product_image.dart';
+import 'widgets/settings_button.dart';
+import 'widgets/store_tag.dart';
 
 class ProductsScreen extends StatefulWidget {
-  const ProductsScreen({
-    super.key,
-    required this.repository,
-    this.savedCount,
-  });
+  const ProductsScreen({super.key, required this.repository});
 
   final ProductRepository repository;
-  final int? savedCount;
 
   @override
   State<ProductsScreen> createState() => _ProductsScreenState();
 }
 
 class _ProductsScreenState extends State<ProductsScreen> {
+  ProductSort _sort = ProductSort.preferred;
+  bool _favouritesOnly = false;
+  bool _searching = false;
+  final TextEditingController _search = TextEditingController();
   late Future<List<Product>> _future;
 
   @override
   void initState() {
     super.initState();
-    _future = widget.repository.getAll();
-    final saved = widget.savedCount;
-    if (saved != null) {
-      WidgetsBinding.instance.addPostFrameCallback((_) {
-        if (!mounted) return;
-        ScaffoldMessenger.of(context).showSnackBar(
-          SnackBar(
-            content: Text(
-              saved == 1
-                  ? 'Saved 1 product.'
-                  : 'Saved $saved products.',
-            ),
-          ),
-        );
-      });
+    _future = _load();
+    _search.addListener(() => setState(() {}));
+  }
+
+  @override
+  void dispose() {
+    _search.dispose();
+    super.dispose();
+  }
+
+  Future<List<Product>> _load() {
+    return widget.repository.getAll(
+      sort: _sort,
+      favouritesOnly: _favouritesOnly,
+    );
+  }
+
+  void _reload() {
+    setState(() => _future = _load());
+  }
+
+  List<Product> _filter(List<Product> products) {
+    final query = _search.text.trim();
+    if (query.isEmpty) return products;
+    final ranked = <({Product product, int score})>[];
+    for (final product in products) {
+      final haystack = [
+        product.name,
+        if (product.supermarket != null) product.supermarket!,
+        if (product.category != null) product.category!,
+        if (product.notes != null) product.notes!,
+      ].join(' ');
+      final score = fuzzyScore(query, haystack);
+      if (score != null) {
+        ranked.add((product: product, score: score));
+      }
     }
+    ranked.sort((a, b) => b.score.compareTo(a.score));
+    return [for (final row in ranked) row.product];
+  }
+
+  Future<void> _openProduct(Product product) async {
+    await Navigator.of(context).push<void>(
+      MaterialPageRoute(
+        builder: (_) => ProductDetailScreen(
+          repository: widget.repository,
+          productId: product.id,
+        ),
+      ),
+    );
+    if (mounted) _reload();
   }
 
   @override
   Widget build(BuildContext context) {
     final theme = Theme.of(context);
+    final stores = SettingsScope.maybeOf(context)?.supermarkets ?? const [];
 
     return Scaffold(
-      appBar: AppBar(title: const Text('Products')),
-      body: FutureBuilder<List<Product>>(
-        future: _future,
-        builder: (context, snapshot) {
-          if (snapshot.hasError) {
-            return Center(
-              child: Text(
-                'Could not load products.',
-                style: theme.textTheme.bodyLarge,
-              ),
-            );
-          }
-          if (!snapshot.hasData) {
-            return const Center(child: CircularProgressIndicator());
-          }
-
-          final products = snapshot.data!;
-          if (products.isEmpty) {
-            return Center(
-              child: Text(
-                'Confirmed receipt items will show up here.',
-                textAlign: TextAlign.center,
-                style: theme.textTheme.bodyLarge,
-              ),
-            );
-          }
-
-          return ListView.separated(
-            padding: const EdgeInsets.symmetric(vertical: 8),
-            itemCount: products.length,
-            separatorBuilder: (_, _) => const Divider(indent: 16, endIndent: 16),
-            itemBuilder: (context, index) {
-              final product = products[index];
-              final seen = product.timesSeen;
-              return ListTile(
-                title: Text(product.name),
-                subtitle: Text(seen == 1 ? 'Seen once' : 'Seen $seen times'),
-                trailing: Text(
-                  formatEuro(product.lastPrice),
-                  style: theme.textTheme.titleMedium,
+      appBar: AppBar(
+        title: _searching
+            ? TextField(
+                controller: _search,
+                autofocus: true,
+                decoration: const InputDecoration(
+                  hintText: 'Search products',
+                  border: InputBorder.none,
+                  enabledBorder: InputBorder.none,
+                  focusedBorder: InputBorder.none,
+                  filled: false,
                 ),
-              );
+              )
+            : const Text('Products'),
+        actions: [
+          IconButton(
+            tooltip: _searching ? 'Close search' : 'Search',
+            onPressed: () {
+              setState(() {
+                _searching = !_searching;
+                if (!_searching) _search.clear();
+              });
             },
-          );
-        },
+            icon: Icon(_searching ? Icons.close : Icons.search),
+          ),
+          const SettingsButton(),
+        ],
+      ),
+      body: Column(
+        children: [
+          Padding(
+            padding: const EdgeInsets.fromLTRB(16, 4, 16, 4),
+            child: Row(
+              children: [
+                Expanded(
+                  child: SegmentedButton<ProductSort>(
+                    segments: const [
+                      ButtonSegment(
+                        value: ProductSort.preferred,
+                        label: Text('Preferred'),
+                      ),
+                      ButtonSegment(
+                        value: ProductSort.name,
+                        label: Text('A–Z'),
+                      ),
+                    ],
+                    selected: {_sort},
+                    onSelectionChanged: (selected) {
+                      setState(() {
+                        _sort = selected.first;
+                        _future = _load();
+                      });
+                    },
+                  ),
+                ),
+                const SizedBox(width: 8),
+                IconButton.filledTonal(
+                  tooltip: 'Favourites',
+                  isSelected: _favouritesOnly,
+                  onPressed: () {
+                    setState(() {
+                      _favouritesOnly = !_favouritesOnly;
+                      _future = _load();
+                    });
+                  },
+                  icon: Icon(
+                    _favouritesOnly ? Icons.star : Icons.star_outline,
+                  ),
+                ),
+              ],
+            ),
+          ),
+          Expanded(
+            child: FutureBuilder<List<Product>>(
+              future: _future,
+              builder: (context, snapshot) {
+                if (snapshot.hasError) {
+                  return Center(
+                    child: Text(
+                      'Could not load products.',
+                      style: theme.textTheme.bodyLarge,
+                    ),
+                  );
+                }
+                if (!snapshot.hasData) {
+                  return const Center(child: CircularProgressIndicator());
+                }
+
+                final products = _filter(snapshot.data!);
+                if (snapshot.data!.isEmpty) {
+                  return Center(
+                    child: Text(
+                      _favouritesOnly
+                          ? 'Star products to keep them as favourites.'
+                          : 'Confirmed receipt items will show up here.',
+                      textAlign: TextAlign.center,
+                      style: theme.textTheme.bodyLarge,
+                    ),
+                  );
+                }
+                if (products.isEmpty) {
+                  return Center(
+                    child: Text(
+                      'No products match this search.',
+                      textAlign: TextAlign.center,
+                      style: theme.textTheme.bodyLarge,
+                    ),
+                  );
+                }
+
+                return ListView.separated(
+                  padding: const EdgeInsets.fromLTRB(8, 0, 8, 16),
+                  itemCount: products.length,
+                  separatorBuilder: (_, _) => const Divider(height: 1),
+                  itemBuilder: (context, index) {
+                    final product = products[index];
+                    return ListTile(
+                      dense: true,
+                      visualDensity: VisualDensity.compact,
+                      contentPadding: const EdgeInsets.symmetric(
+                        horizontal: 8,
+                        vertical: 0,
+                      ),
+                      leading: ProductImage(
+                        name: product.name,
+                        path: product.imagePath,
+                        size: 36,
+                      ),
+                      title: Text(
+                        product.name,
+                        maxLines: 1,
+                        overflow: TextOverflow.ellipsis,
+                      ),
+                      subtitle: product.supermarket == null
+                          ? null
+                          : Padding(
+                              padding: const EdgeInsets.only(top: 2),
+                              child: Align(
+                                alignment: Alignment.centerLeft,
+                                child: StoreTag(
+                                  name: product.supermarket,
+                                  stores: stores,
+                                  compact: true,
+                                ),
+                              ),
+                            ),
+                      trailing: Text(
+                        formatEuro(product.lastPrice),
+                        style: theme.textTheme.titleMedium,
+                      ),
+                      onTap: () => _openProduct(product),
+                    );
+                  },
+                );
+              },
+            ),
+          ),
+        ],
       ),
     );
   }

lib/review_screen.dart

@@ -1,12 +1,15 @@
-/// Editable list of parsed receipt lines before they are saved as products.
+/// Editable list of parsed receipt lines before they are saved as a shop trip.
 library;
 
 import 'package:flutter/material.dart';
 
 import 'models/line_item.dart';
-import 'products_screen.dart';
+import 'services/app_settings.dart';
 import 'services/product_repository.dart';
+import 'utils/dates.dart';
 import 'utils/money.dart';
+import 'utils/supermarkets.dart';
+import 'widgets/store_tag.dart';
 
 class ReviewScreen extends StatefulWidget {
   const ReviewScreen({
@@ -14,11 +17,15 @@ class ReviewScreen extends StatefulWidget {
     required this.items,
     required this.rawText,
     required this.repository,
+    this.imagePath,
+    this.supermarketNames = kSupermarkets,
   });
 
   final List<LineItem> items;
   final String rawText;
   final ProductRepository repository;
+  final String? imagePath;
+  final List<String> supermarketNames;
 
   @override
   State<ReviewScreen> createState() => _ReviewScreenState();
@@ -26,12 +33,33 @@ class ReviewScreen extends StatefulWidget {
 
 class _ReviewScreenState extends State<ReviewScreen> {
   late List<LineItem> _items;
+  late DateTime _shoppedAt;
+  String? _supermarket;
+  String? _customStore;
   bool _saving = false;
 
   @override
   void initState() {
     super.initState();
     _items = List<LineItem>.from(widget.items);
+    _shoppedAt = DateTime.now();
+    final detected = detectSupermarket(
+      widget.rawText,
+      names: widget.supermarketNames,
+    );
+    if (detected != null) {
+      _supermarket = detected;
+    }
+  }
+
+  String? get _resolvedSupermarket {
+    if (_supermarket == null) return null;
+    if (_supermarket == kOtherSupermarket) {
+      final custom = _customStore?.trim();
+      if (custom == null || custom.isEmpty) return null;
+      return custom;
+    }
+    return _supermarket;
   }
 
   Future<void> _edit({LineItem? existing}) async {
@@ -55,25 +83,47 @@ class _ReviewScreenState extends State<ReviewScreen> {
     });
   }
 
+  Future<void> _pickDate() async {
+    final picked = await showDatePicker(
+      context: context,
+      initialDate: _shoppedAt,
+      firstDate: DateTime(2018),
+      lastDate: DateTime.now().add(const Duration(days: 1)),
+    );
+    if (picked == null || !mounted) return;
+    setState(() => _shoppedAt = picked);
+  }
+
   Future<void> _confirm() async {
+    final supermarket = _resolvedSupermarket;
+    if (supermarket == null) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        const SnackBar(content: Text('Select a supermarket.')),
+      );
+      return;
+    }
+    if (_items.isEmpty) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        const SnackBar(content: Text('Add at least one product.')),
+      );
+      return;
+    }
+
     setState(() => _saving = true);
     try {
-      await widget.repository.upsertItems(_items);
-      if (!mounted) return;
-      Navigator.of(context).pushAndRemoveUntil(
-        MaterialPageRoute<void>(
-          builder: (_) => ProductsScreen(
-            repository: widget.repository,
-            savedCount: _items.length,
-          ),
-        ),
-        (route) => route.isFirst,
+      await widget.repository.saveShop(
+        supermarket: supermarket,
+        shoppedAt: _shoppedAt,
+        items: _items,
+        receiptImagePath: widget.imagePath,
       );
+      if (!mounted) return;
+      Navigator.of(context).pop(true);
     } catch (_) {
       if (!mounted) return;
       setState(() => _saving = false);
       ScaffoldMessenger.of(context).showSnackBar(
-        const SnackBar(content: Text('Could not save products.')),
+        const SnackBar(content: Text('Could not save this shopping trip.')),
       );
     }
   }
@@ -81,11 +131,69 @@ class _ReviewScreenState extends State<ReviewScreen> {
   @override
   Widget build(BuildContext context) {
     final theme = Theme.of(context);
+    final total = _items.fold<double>(0, (sum, item) => sum + item.price);
+    final settings = SettingsScope.maybeOf(context);
+    final stores = settings?.supermarkets ?? kDefaultSupermarkets;
+    final names = [
+      ...{...widget.supermarketNames, ...stores.map((s) => s.name)},
+    ];
+    if (_supermarket != null && !names.contains(_supermarket)) {
+      names.add(_supermarket!);
+    }
 
     return Scaffold(
       appBar: AppBar(title: const Text('Review items')),
       body: Column(
         children: [
+          Padding(
+            padding: const EdgeInsets.fromLTRB(16, 8, 16, 0),
+            child: Column(
+              crossAxisAlignment: CrossAxisAlignment.stretch,
+              children: [
+                DropdownButtonFormField<String>(
+                  key: ValueKey(_supermarket),
+                  initialValue: _supermarket,
+                  hint: const Text('Select supermarket'),
+                  decoration: const InputDecoration(
+                    labelText: 'Supermarket',
+                  ),
+                  items: [
+                    for (final store in names)
+                      DropdownMenuItem(
+                        value: store,
+                        child: StoreTag(
+                          name: store,
+                          stores: stores,
+                          compact: true,
+                        ),
+                      ),
+                  ],
+                  onChanged: _saving
+                      ? null
+                      : (value) => setState(() => _supermarket = value),
+                ),
+                if (_supermarket == kOtherSupermarket) ...[
+                  const SizedBox(height: 12),
+                  TextField(
+                    enabled: !_saving,
+                    textCapitalization: TextCapitalization.words,
+                    decoration: const InputDecoration(
+                      labelText: 'Store name',
+                    ),
+                    onChanged: (value) => _customStore = value,
+                  ),
+                ],
+                const SizedBox(height: 8),
+                ListTile(
+                  contentPadding: EdgeInsets.zero,
+                  leading: const Icon(Icons.calendar_today_outlined),
+                  title: Text(formatDate(_shoppedAt)),
+                  subtitle: const Text('Shopping date'),
+                  onTap: _saving ? null : _pickDate,
+                ),
+              ],
+            ),
+          ),
           Expanded(
             child: _items.isEmpty
                 ? Center(
@@ -166,7 +274,9 @@ class _ReviewScreenState extends State<ReviewScreen> {
                   FilledButton(
                     onPressed: _saving ? null : _confirm,
                     child: Text(
-                      _saving ? 'Saving…' : 'Confirm',
+                      _saving
+                          ? 'Saving…'
+                          : 'Save trip · ${formatEuro(total)}',
                     ),
                   ),
                 ],

lib/scan_screen.dart

@@ -1,4 +1,4 @@
-/// Single screen: capture or pick a receipt photo, then show raw OCR text.
+/// Capture or pick a receipt photo, then review parsed line items.
 library;
 
 import 'dart:io';
@@ -8,16 +8,23 @@ import 'package:flutter/services.dart';
 import 'package:google_mlkit_text_recognition/google_mlkit_text_recognition.dart';
 import 'package:image_picker/image_picker.dart';
 
-import 'products_screen.dart';
 import 'review_screen.dart';
+import 'services/app_settings.dart';
 import 'services/product_repository.dart';
 import 'services/receipt_parser.dart';
 import 'utils/constants.dart';
+import 'utils/supermarkets.dart';
+import 'widgets/settings_button.dart';
 
 class ScanScreen extends StatefulWidget {
-  const ScanScreen({super.key, required this.repository});
+  const ScanScreen({
+    super.key,
+    required this.repository,
+    this.onTripSaved,
+  });
 
   final ProductRepository repository;
+  final VoidCallback? onTripSaved;
 
   @override
   State<ScanScreen> createState() => _ScanScreenState();
@@ -27,6 +34,7 @@ class _ScanScreenState extends State<ScanScreen> {
   final ImagePicker _picker = ImagePicker();
 
   String _extractedText = '';
+  String? _imagePath;
   bool _busy = false;
   String? _error;
 
@@ -81,6 +89,7 @@ class _ScanScreenState extends State<ScanScreen> {
       _busy = true;
       _error = null;
       _extractedText = '';
+      _imagePath = imagePath;
     });
 
     final recognizer = TextRecognizer(script: TextRecognitionScript.latin);
@@ -114,23 +123,23 @@ class _ScanScreenState extends State<ScanScreen> {
   Future<void> _openReview(String rawText) async {
     final items = ReceiptParser.parse(rawText);
     if (!mounted) return;
-    await Navigator.of(context).push(
-      MaterialPageRoute<void>(
+    final names =
+        SettingsScope.maybeOf(context)?.supermarkets.map((s) => s.name) ??
+        kSupermarkets;
+    final saved = await Navigator.of(context).push<bool>(
+      MaterialPageRoute(
         builder: (_) => ReviewScreen(
           items: items,
           rawText: rawText,
           repository: widget.repository,
+          imagePath: _imagePath,
+          supermarketNames: names.toList(),
         ),
       ),
     );
-  }
-
-  void _openProducts() {
-    Navigator.of(context).push(
-      MaterialPageRoute<void>(
-        builder: (_) => ProductsScreen(repository: widget.repository),
-      ),
-    );
+    if (saved == true && mounted) {
+      widget.onTripSaved?.call();
+    }
   }
 
   @override
@@ -140,13 +149,7 @@ class _ScanScreenState extends State<ScanScreen> {
     return Scaffold(
       appBar: AppBar(
         title: const Text(kAppName),
-        actions: [
-          IconButton(
-            tooltip: 'Products',
-            onPressed: _openProducts,
-            icon: const Icon(Icons.inventory_2_outlined),
-          ),
-        ],
+        actions: const [SettingsButton()],
       ),
       body: SafeArea(
         child: Padding(
@@ -220,7 +223,7 @@ class _ResultPane extends StatelessWidget {
     if (text.isEmpty) {
       return Center(
         child: Text(
-          'Take a photo of a shopping receipt, or pick one from the gallery.\n\nExtracted text will show up here.',
+          'Take a photo of a shopping receipt, or pick one from the gallery.\n\nConfirmed trips show up in Shop log.',
           textAlign: TextAlign.center,
           style: theme.textTheme.bodyLarge,
         ),

lib/services/app_settings.dart

@@ -0,0 +1,89 @@
+/// App-wide settings: dark mode and the user supermarket list.
+library;
+
+import 'package:flutter/material.dart';
+
+import '../models/supermarket.dart';
+import '../utils/supermarkets.dart';
+import 'product_repository.dart';
+
+class AppSettings extends ChangeNotifier {
+  AppSettings(this.repository);
+
+  final ProductRepository repository;
+
+  bool darkMode = false;
+  List<Supermarket> supermarkets = List<Supermarket>.from(kDefaultSupermarkets);
+  int catalogGeneration = 0;
+
+  Future<void> load() async {
+    try {
+      darkMode = await repository.getDarkMode();
+      supermarkets = await repository.getSupermarkets();
+      notifyListeners();
+    } catch (_) {
+      // Widget tests and first-run without a plugin keep the defaults.
+    }
+  }
+
+  Future<void> setDarkMode(bool enabled) async {
+    darkMode = enabled;
+    notifyListeners();
+    try {
+      await repository.setDarkMode(enabled);
+    } catch (_) {}
+  }
+
+  Future<void> addSupermarket(String name, int colorValue) async {
+    final trimmed = name.trim();
+    if (trimmed.isEmpty) return;
+    final store = await repository.addSupermarket(
+      name: trimmed,
+      colorValue: colorValue,
+    );
+    supermarkets = [...supermarkets, store];
+    notifyListeners();
+  }
+
+  Future<void> updateSupermarket(Supermarket store) async {
+    await repository.updateSupermarket(store);
+    supermarkets = [
+      for (final item in supermarkets)
+        if (item.id == store.id) store else item,
+    ];
+    notifyListeners();
+  }
+
+  Future<void> deleteSupermarket(int id) async {
+    await repository.deleteSupermarket(id);
+    supermarkets = [
+      for (final item in supermarkets)
+        if (item.id != id) item,
+    ];
+    notifyListeners();
+  }
+
+  Future<void> reload() async {
+    await load();
+    catalogGeneration++;
+    notifyListeners();
+  }
+}
+
+class SettingsScope extends InheritedNotifier<AppSettings> {
+  const SettingsScope({
+    super.key,
+    required AppSettings settings,
+    required super.child,
+  }) : super(notifier: settings);
+
+  static AppSettings of(BuildContext context) {
+    final scope = context.dependOnInheritedWidgetOfExactType<SettingsScope>();
+    assert(scope != null, 'SettingsScope not found');
+    return scope!.notifier!;
+  }
+
+  static AppSettings? maybeOf(BuildContext context) {
+    return context.dependOnInheritedWidgetOfExactType<SettingsScope>()?.notifier;
+  }
+}

lib/services/backup_format.dart

@@ -0,0 +1,99 @@
+/// JSON backup document: products, trips, settings, and embedded photos.
+library;
+
+import 'dart:convert';
+
+const int kBackupVersion = 1;
+
+class BackupDocument {
+  const BackupDocument({
+    required this.version,
+    required this.exportedAt,
+    required this.darkMode,
+    required this.supermarkets,
+    required this.products,
+    required this.shops,
+    required this.shopItems,
+    required this.images,
+  });
+
+  final int version;
+  final String exportedAt;
+  final bool darkMode;
+  final List<Map<String, Object?>> supermarkets;
+  final List<Map<String, Object?>> products;
+  final List<Map<String, Object?>> shops;
+  final List<Map<String, Object?>> shopItems;
+  final Map<String, String> images;
+
+  Map<String, Object?> toJson() => {
+    'format': 'receipity-backup',
+    'version': version,
+    'exportedAt': exportedAt,
+    'darkMode': darkMode,
+    'supermarkets': supermarkets,
+    'products': products,
+    'shops': shops,
+    'shopItems': shopItems,
+    'images': images,
+  };
+
+  String encode() => const JsonEncoder.withIndent('  ').convert(toJson());
+
+  static BackupDocument parse(String json) {
+    final decoded = jsonDecode(json);
+    if (decoded is! Map<String, dynamic>) {
+      throw const FormatException('Backup is not a JSON object.');
+    }
+    if (decoded['format'] != 'receipity-backup') {
+      throw const FormatException('This file is not a Receipity backup.');
+    }
+    final version = decoded['version'];
+    if (version is! int || version < 1 || version > kBackupVersion) {
+      throw const FormatException('Unsupported backup version.');
+    }
+    return BackupDocument(
+      version: version,
+      exportedAt: decoded['exportedAt'] as String? ?? '',
+      darkMode: decoded['darkMode'] == true,
+      supermarkets: _maps(decoded['supermarkets']),
+      products: _maps(decoded['products']),
+      shops: _maps(decoded['shops']),
+      shopItems: _maps(decoded['shopItems']),
+      images: _strings(decoded['images']),
+    );
+  }
+
+  static List<Map<String, Object?>> _maps(Object? value) {
+    if (value == null) return [];
+    if (value is! List) {
+      throw const FormatException('Backup tables must be lists.');
+    }
+    return [
+      for (final item in value)
+        if (item is Map)
+          Map<String, Object?>.from(
+            item.map((key, val) => MapEntry(key.toString(), val)),
+          ),
+    ];
+  }
+
+  static Map<String, String> _strings(Object? value) {
+    if (value == null) return {};
+    if (value is! Map) return {};
+    return {
+      for (final entry in value.entries)
+        if (entry.value is String) entry.key.toString(): entry.value as String,
+    };
+  }
+}
+
+String? backupImageKey(String? absolutePath) {
+  if (absolutePath == null || absolutePath.isEmpty) return null;
+  final normalized = absolutePath.replaceAll('\\', '/');
+  final products = normalized.split('/products/');
+  if (products.length == 2) return 'products/${products.last}';
+  final receipts = normalized.split('/receipts/');
+  if (receipts.length == 2) return 'receipts/${receipts.last}';
+  return null;
+}

lib/services/backup_service.dart

@@ -0,0 +1,161 @@
+/// Build, share, and restore a Receipity JSON backup.
+library;
+
+import 'dart:convert';
+import 'dart:io';
+import 'dart:typed_data';
+
+import 'package:file_picker/file_picker.dart';
+import 'package:path/path.dart' as p;
+import 'package:path_provider/path_provider.dart';
+import 'package:share_plus/share_plus.dart';
+
+import 'backup_format.dart';
+import 'product_repository.dart';
+
+class BackupService {
+  BackupService(this.repository);
+
+  final ProductRepository repository;
+
+  Future<BackupDocument> buildBackup() async {
+    final products = await repository.dumpTable('products');
+    final shops = await repository.dumpTable('shops');
+    final images = <String, String>{};
+
+    Future<void> addImage(String? path) async {
+      final key = backupImageKey(path);
+      if (key == null || images.containsKey(key)) return;
+      final file = File(path!);
+      if (!file.existsSync()) return;
+      images[key] = base64Encode(await file.readAsBytes());
+    }
+
+    final rewrittenProducts = <Map<String, Object?>>[];
+    for (final row in products) {
+      final copy = Map<String, Object?>.from(row);
+      final path = copy['image_path'] as String?;
+      await addImage(path);
+      copy['image_path'] = backupImageKey(path);
+      rewrittenProducts.add(copy);
+    }
+
+    final rewrittenShops = <Map<String, Object?>>[];
+    for (final row in shops) {
+      final copy = Map<String, Object?>.from(row);
+      final path = copy['receipt_image_path'] as String?;
+      await addImage(path);
+      copy['receipt_image_path'] = backupImageKey(path);
+      rewrittenShops.add(copy);
+    }
+
+    return BackupDocument(
+      version: kBackupVersion,
+      exportedAt: DateTime.now().toIso8601String(),
+      darkMode: await repository.getDarkMode(),
+      supermarkets: await repository.dumpTable('supermarkets'),
+      products: rewrittenProducts,
+      shops: rewrittenShops,
+      shopItems: await repository.dumpTable('shop_items'),
+      images: images,
+    );
+  }
+
+  Future<bool> exportBackup() async {
+    final document = await buildBackup();
+    final bytes = Uint8List.fromList(utf8.encode(document.encode()));
+    final stamp = DateTime.now().toIso8601String().split('T').first;
+    final fileName = 'receipity-backup-$stamp.json';
+
+    try {
+      final saved = await FilePicker.saveFile(
+        dialogTitle: 'Save Receipity backup',
+        fileName: fileName,
+        bytes: bytes,
+        mimeType: 'application/json',
+        type: FileType.custom,
+        allowedExtensions: const ['json'],
+      );
+      return saved != null;
+    } catch (_) {
+      // Fall through to the share sheet if save-as is unavailable.
+    }
+
+    final dir = await getTemporaryDirectory();
+    final file = File(p.join(dir.path, fileName));
+    await file.writeAsBytes(bytes, flush: true);
+    final result = await SharePlus.instance.share(
+      ShareParams(
+        files: [XFile(file.path, mimeType: 'application/json')],
+        subject: 'Receipity backup',
+        text: 'Receipity backup $stamp',
+      ),
+    );
+    return result.status != ShareResultStatus.dismissed;
+  }
+
+  Future<bool> importBackup() async {
+    final picked = await FilePicker.pickFile(
+      dialogTitle: 'Import Receipity backup',
+      type: FileType.custom,
+      allowedExtensions: const ['json'],
+    );
+    if (picked == null) return false;
+    final bytes = await picked.readAsBytes();
+    await restoreBackup(utf8.decode(bytes));
+    return true;
+  }
+
+  Future<void> restoreBackup(String json) async {
+    final document = BackupDocument.parse(json);
+    await repository.clearImageFolders();
+
+    final products = <Map<String, Object?>>[];
+    final now = DateTime.now().toIso8601String();
+    for (final row in document.products) {
+      final copy = Map<String, Object?>.from(row);
+      copy['image_path'] = await _restoreImage(copy['image_path'], document.images);
+      copy['created_at'] ??= now;
+      copy['updated_at'] ??= copy['created_at'];
+      if (copy['normalized_name'] == null && copy['name'] is String) {
+        copy['normalized_name'] = ProductRepository.normalizeName(
+          copy['name']! as String,
+        );
+      }
+      products.add(copy);
+    }
+
+    final shops = <Map<String, Object?>>[];
+    for (final row in document.shops) {
+      final copy = Map<String, Object?>.from(row);
+      copy['receipt_image_path'] = await _restoreImage(
+        copy['receipt_image_path'],
+        document.images,
+      );
+      copy['created_at'] ??= now;
+      shops.add(copy);
+    }
+
+    await repository.replaceAllData(
+      supermarkets: document.supermarkets,
+      products: products,
+      shops: shops,
+      shopItems: document.shopItems,
+      darkMode: document.darkMode,
+    );
+  }
+
+  Future<String?> _restoreImage(
+    Object? key,
+    Map<String, String> images,
+  ) async {
+    if (key is! String || key.isEmpty) return null;
+    final encoded = images[key];
+    if (encoded == null) return null;
+    try {
+      return await repository.writeImageBytes(key, base64Decode(encoded));
+    } catch (_) {
+      return null;
+    }
+  }
+}

lib/services/product_repository.dart

@@ -1,14 +1,24 @@
-/// Local SQLite store of confirmed products.
+/// Local SQLite store of products and shopping trips.
 library;
 
+import 'dart:io';
+
 import 'package:path/path.dart' as p;
 import 'package:path_provider/path_provider.dart';
 import 'package:sqflite/sqflite.dart';
 
 import '../models/line_item.dart';
 import '../models/product.dart';
+import '../models/purchase.dart';
+import '../models/shop.dart';
+import '../models/supermarket.dart';
+import '../utils/money.dart';
+import '../utils/supermarkets.dart';
 
 class ProductRepository {
+  ProductRepository({this.databasePath});
+
+  final String? databasePath;
   Database? _db;
 
   Future<Database> get _database async {
@@ -17,77 +27,664 @@ class ProductRepository {
   }
 
   Future<Database> _open() async {
-    final dir = await getApplicationDocumentsDirectory();
+    final path = databasePath ??
+        p.join((await getApplicationDocumentsDirectory()).path, 'receipity.db');
     return openDatabase(
-      p.join(dir.path, 'receipity.db'),
-      version: 1,
+      path,
+      version: 4,
       onCreate: (db, version) async {
-        await db.execute('''
-          CREATE TABLE products (
-            id INTEGER PRIMARY KEY AUTOINCREMENT,
-            name TEXT NOT NULL,
-            normalized_name TEXT NOT NULL UNIQUE,
-            last_price REAL NOT NULL,
-            times_seen INTEGER NOT NULL DEFAULT 1,
-            created_at TEXT NOT NULL,
-            updated_at TEXT NOT NULL
-          )
-        ''');
+        await _createProducts(db);
+        await _createShopTables(db);
+        await _createSettingsTables(db);
+        await _seedSupermarkets(db);
+      },
+      onUpgrade: (db, oldVersion, newVersion) async {
+        if (oldVersion < 2) {
+          await db.execute(
+            'ALTER TABLE products ADD COLUMN favourite INTEGER NOT NULL DEFAULT 0',
+          );
+          await db.execute('ALTER TABLE products ADD COLUMN image_path TEXT');
+          await db.execute('ALTER TABLE products ADD COLUMN supermarket TEXT');
+          await _createShopTables(db);
+        }
+        if (oldVersion < 3) {
+          await db.execute('ALTER TABLE products ADD COLUMN notes TEXT');
+          await _createSettingsTables(db);
+          await _seedSupermarkets(db);
+        }
+        if (oldVersion < 4) {
+          await db.execute('ALTER TABLE products ADD COLUMN category TEXT');
+        }
       },
     );
   }
 
+  Future<void> _createProducts(Database db) async {
+    await db.execute('''
+      CREATE TABLE products (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        name TEXT NOT NULL,
+        normalized_name TEXT NOT NULL UNIQUE,
+        last_price REAL NOT NULL,
+        times_seen INTEGER NOT NULL DEFAULT 1,
+        favourite INTEGER NOT NULL DEFAULT 0,
+        image_path TEXT,
+        supermarket TEXT,
+        notes TEXT,
+        category TEXT,
+        created_at TEXT NOT NULL,
+        updated_at TEXT NOT NULL
+      )
+    ''');
+  }
+
+  Future<void> _createSettingsTables(DatabaseExecutor db) async {
+    await db.execute('''
+      CREATE TABLE IF NOT EXISTS app_settings (
+        key TEXT PRIMARY KEY,
+        value TEXT NOT NULL
+      )
+    ''');
+    await db.execute('''
+      CREATE TABLE IF NOT EXISTS supermarkets (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        name TEXT NOT NULL UNIQUE,
+        color INTEGER NOT NULL,
+        sort_order INTEGER NOT NULL
+      )
+    ''');
+  }
+
+  Future<void> _seedSupermarkets(DatabaseExecutor db) async {
+    final existing = await db.query('supermarkets', limit: 1);
+    if (existing.isNotEmpty) return;
+    for (final store in kDefaultSupermarkets) {
+      await db.insert('supermarkets', {
+        'name': store.name,
+        'color': store.colorValue,
+        'sort_order': store.sortOrder,
+      });
+    }
+  }
+
+  Future<void> _createShopTables(DatabaseExecutor db) async {
+    await db.execute('''
+      CREATE TABLE shops (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        supermarket TEXT NOT NULL,
+        shopped_at TEXT NOT NULL,
+        receipt_image_path TEXT,
+        total REAL NOT NULL,
+        created_at TEXT NOT NULL
+      )
+    ''');
+    await db.execute('''
+      CREATE TABLE shop_items (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        shop_id INTEGER NOT NULL,
+        product_id INTEGER NOT NULL,
+        name TEXT NOT NULL,
+        price REAL NOT NULL,
+        quantity INTEGER,
+        unit_price REAL,
+        FOREIGN KEY (shop_id) REFERENCES shops(id) ON DELETE CASCADE,
+        FOREIGN KEY (product_id) REFERENCES products(id)
+      )
+    ''');
+  }
+
   static String normalizeName(String name) =>
       name.trim().toUpperCase().replaceAll(RegExp(r'\s+'), ' ');
 
-  Future<void> upsertItems(List<LineItem> items) async {
+  Future<String> _persistImage(String sourcePath, String relativePath) async {
+    final dir = await getApplicationDocumentsDirectory();
+    final dest = File(p.join(dir.path, relativePath));
+    await dest.parent.create(recursive: true);
+    if (p.normalize(sourcePath) == p.normalize(dest.path)) {
+      return dest.path;
+    }
+    await File(sourcePath).copy(dest.path);
+    return dest.path;
+  }
+
+  /// Saves a shopping trip and upserts each line into the product catalog.
+  Future<int> saveShop({
+    required String supermarket,
+    required DateTime shoppedAt,
+    required List<LineItem> items,
+    String? receiptImagePath,
+  }) async {
     final db = await _database;
     final now = DateTime.now().toIso8601String();
+    final total = roundMoney(
+      items.fold<double>(0, (sum, item) => sum + item.price),
+    );
+
+    final shopId = await db.transaction((txn) async {
+      final id = await txn.insert('shops', {
+        'supermarket': supermarket,
+        'shopped_at': shoppedAt.toIso8601String(),
+        'total': total,
+        'created_at': now,
+      });
 
-    await db.transaction((txn) async {
       for (final item in items) {
-        final key = normalizeName(item.name);
-        if (key.isEmpty) continue;
-
-        final existing = await txn.query(
-          'products',
-          where: 'normalized_name = ?',
-          whereArgs: [key],
-          limit: 1,
+        final productId = await _upsertProduct(
+          txn,
+          item: item,
+          supermarket: supermarket,
+          now: now,
         );
-
-        if (existing.isEmpty) {
-          await txn.insert('products', {
-            'name': item.name.trim(),
-            'normalized_name': key,
-            'last_price': item.price,
-            'times_seen': 1,
-            'created_at': now,
-            'updated_at': now,
-          });
-        } else {
-          await txn.update(
-            'products',
-            {
-              'name': item.name.trim(),
-              'last_price': item.price,
-              'times_seen': (existing.first['times_seen']! as int) + 1,
-              'updated_at': now,
-            },
-            where: 'id = ?',
-            whereArgs: [existing.first['id']],
-          );
-        }
+        await txn.insert('shop_items', {
+          'shop_id': id,
+          'product_id': productId,
+          'name': item.name.trim(),
+          'price': item.price,
+          'quantity': item.quantity,
+          'unit_price': item.unitPrice,
+        });
       }
+      return id;
+    });
+
+    if (receiptImagePath != null && receiptImagePath.isNotEmpty) {
+      try {
+        final stored = await _persistImage(
+          receiptImagePath,
+          'receipts/shop_$shopId.jpg',
+        );
+        await db.update(
+          'shops',
+          {'receipt_image_path': stored},
+          where: 'id = ?',
+          whereArgs: [shopId],
+        );
+      } catch (_) {
+        // Trip is still saved if the photo cannot be copied.
+      }
+    }
+
+    return shopId;
+  }
+
+  Future<int> _upsertProduct(
+    Transaction txn, {
+    required LineItem item,
+    required String supermarket,
+    required String now,
+  }) async {
+    final key = normalizeName(item.name);
+    final existing = await txn.query(
+      'products',
+      where: 'normalized_name = ?',
+      whereArgs: [key],
+      limit: 1,
+    );
+
+    if (existing.isEmpty) {
+      return txn.insert('products', {
+        'name': item.name.trim(),
+        'normalized_name': key,
+        'last_price': item.unitPrice ?? item.price,
+        'times_seen': 1,
+        'favourite': 0,
+        'supermarket': supermarket,
+        'created_at': now,
+        'updated_at': now,
+      });
+    }
+
+    final row = existing.first;
+    final values = <String, Object?>{
+      'last_price': item.unitPrice ?? item.price,
+      'times_seen': (row['times_seen']! as int) + 1,
+      'updated_at': now,
+    };
+    if ((row['supermarket'] as String?) == null ||
+        (row['supermarket'] as String).isEmpty) {
+      values['supermarket'] = supermarket;
+    }
+    await txn.update(
+      'products',
+      values,
+      where: 'id = ?',
+      whereArgs: [row['id']],
+    );
+    return row['id']! as int;
+  }
+
+  /// Kept for tests and older callers; saves items without a shop trip.
+  Future<void> upsertItems(List<LineItem> items) async {
+    await saveShop(
+      supermarket: 'Other',
+      shoppedAt: DateTime.now(),
+      items: items,
+    );
+  }
+
+  Future<List<Product>> getAll({
+    ProductSort sort = ProductSort.name,
+    bool favouritesOnly = false,
+  }) async {
+    final db = await _database;
+    final orderBy = switch (sort) {
+      ProductSort.name => 'name COLLATE NOCASE ASC',
+      ProductSort.preferred => 'times_seen DESC, name COLLATE NOCASE ASC',
+    };
+    final rows = await db.rawQuery('''
+      SELECT
+        products.*,
+        (
+          SELECT COALESCE(shop_items.unit_price, shop_items.price)
+          FROM shop_items
+          JOIN shops ON shops.id = shop_items.shop_id
+          WHERE shop_items.product_id = products.id
+          ORDER BY shops.shopped_at DESC, shop_items.id DESC
+          LIMIT 1
+        ) AS display_price
+      FROM products
+      ${favouritesOnly ? 'WHERE favourite = 1' : ''}
+      ORDER BY $orderBy
+    ''');
+    return rows.map(Product.fromMap).toList();
+  }
+
+  Future<Product?> getProduct(int id) async {
+    final db = await _database;
+    final rows = await db.rawQuery(
+      '''
+      SELECT
+        products.*,
+        (
+          SELECT COALESCE(shop_items.unit_price, shop_items.price)
+          FROM shop_items
+          JOIN shops ON shops.id = shop_items.shop_id
+          WHERE shop_items.product_id = products.id
+          ORDER BY shops.shopped_at DESC, shop_items.id DESC
+          LIMIT 1
+        ) AS display_price
+      FROM products
+      WHERE products.id = ?
+      LIMIT 1
+      ''',
+      [id],
+    );
+    if (rows.isEmpty) return null;
+    return Product.fromMap(rows.first);
+  }
+
+  Future<List<String>> getUsedCategories() async {
+    final db = await _database;
+    final rows = await db.rawQuery(
+      '''
+      SELECT DISTINCT category FROM products
+      WHERE category IS NOT NULL AND TRIM(category) != ''
+      ORDER BY category COLLATE NOCASE ASC
+      ''',
+    );
+    return [
+      for (final row in rows)
+        if (row['category'] is String) row['category']! as String,
+    ];
+  }
+
+  Future<void> updateProduct({
+    required int id,
+    String? name,
+    bool? favourite,
+    String? supermarket,
+    String? imagePath,
+    String? notes,
+    String? category,
+    bool clearImage = false,
+    bool clearSupermarket = false,
+    bool clearNotes = false,
+    bool clearCategory = false,
+  }) async {
+    final db = await _database;
+    final values = <String, Object?>{
+      'updated_at': DateTime.now().toIso8601String(),
+    };
+    if (name != null) {
+      values['name'] = name.trim();
+      values['normalized_name'] = normalizeName(name);
+    }
+    if (favourite != null) values['favourite'] = favourite ? 1 : 0;
+    if (clearSupermarket) {
+      values['supermarket'] = null;
+    } else if (supermarket != null) {
+      values['supermarket'] = supermarket;
+    }
+    if (clearImage) {
+      values['image_path'] = null;
+    } else if (imagePath != null) {
+      values['image_path'] = imagePath;
+    }
+    if (clearNotes) {
+      values['notes'] = null;
+    } else if (notes != null) {
+      values['notes'] = notes;
+    }
+    if (clearCategory) {
+      values['category'] = null;
+    } else if (category != null) {
+      values['category'] = category.trim();
+    }
+    await db.update('products', values, where: 'id = ?', whereArgs: [id]);
+  }
+
+  Future<void> setFavourite(int id, bool favourite) =>
+      updateProduct(id: id, favourite: favourite);
+
+  Future<String?> setProductImage(int id, String sourcePath) async {
+    final stored = await _persistImage(sourcePath, 'products/product_$id.jpg');
+    await updateProduct(id: id, imagePath: stored);
+    return stored;
+  }
+
+  Future<List<Purchase>> getPurchases(int productId) async {
+    final db = await _database;
+    final rows = await db.rawQuery(
+      '''
+      SELECT
+        shop_items.shop_id,
+        shop_items.price,
+        shop_items.quantity,
+        shop_items.unit_price,
+        shops.shopped_at,
+        shops.supermarket,
+        shops.receipt_image_path
+      FROM shop_items
+      JOIN shops ON shops.id = shop_items.shop_id
+      WHERE shop_items.product_id = ?
+      ORDER BY shops.shopped_at DESC, shop_items.id DESC
+      ''',
+      [productId],
+    );
+    return rows.map(Purchase.fromMap).toList();
+  }
+
+  Future<List<Shop>> getShops() async {
+    final db = await _database;
+    final rows = await db.rawQuery('''
+      SELECT
+        shops.id,
+        shops.supermarket,
+        shops.shopped_at,
+        shops.receipt_image_path,
+        shops.total,
+        COUNT(shop_items.id) AS item_count
+      FROM shops
+      LEFT JOIN shop_items ON shop_items.shop_id = shops.id
+      GROUP BY shops.id
+      ORDER BY shops.shopped_at DESC, shops.id DESC
+    ''');
+    return rows.map(Shop.fromMap).toList();
+  }
+
+  Future<Shop?> getShop(int id) async {
+    final db = await _database;
+    final rows = await db.rawQuery(
+      '''
+      SELECT
+        shops.id,
+        shops.supermarket,
+        shops.shopped_at,
+        shops.receipt_image_path,
+        shops.total,
+        COUNT(shop_items.id) AS item_count
+      FROM shops
+      LEFT JOIN shop_items ON shop_items.shop_id = shops.id
+      WHERE shops.id = ?
+      GROUP BY shops.id
+      ''',
+      [id],
+    );
+    if (rows.isEmpty) return null;
+    return Shop.fromMap(rows.first);
+  }
+
+  Future<List<ShopItem>> getShopItems(int shopId) async {
+    final db = await _database;
+    final rows = await db.query(
+      'shop_items',
+      where: 'shop_id = ?',
+      whereArgs: [shopId],
+      orderBy: 'id ASC',
+    );
+    return rows.map(ShopItem.fromMap).toList();
+  }
+
+  Future<bool> getDarkMode() async {
+    final db = await _database;
+    final rows = await db.query(
+      'app_settings',
+      where: 'key = ?',
+      whereArgs: ['dark_mode'],
+      limit: 1,
+    );
+    if (rows.isEmpty) return false;
+    return rows.first['value'] == '1';
+  }
+
+  Future<void> setDarkMode(bool enabled) async {
+    final db = await _database;
+    await db.insert(
+      'app_settings',
+      {'key': 'dark_mode', 'value': enabled ? '1' : '0'},
+      conflictAlgorithm: ConflictAlgorithm.replace,
+    );
+  }
+
+  Future<List<Supermarket>> getSupermarkets() async {
+    final db = await _database;
+    final rows = await db.query('supermarkets', orderBy: 'sort_order ASC, id ASC');
+    if (rows.isEmpty) {
+      await _seedSupermarkets(db);
+      return getSupermarkets();
+    }
+    return rows.map(Supermarket.fromMap).toList();
+  }
+
+  Future<Supermarket> addSupermarket({
+    required String name,
+    required int colorValue,
+  }) async {
+    final db = await _database;
+    final maxOrder = Sqflite.firstIntValue(
+      await db.rawQuery('SELECT MAX(sort_order) FROM supermarkets'),
+    );
+    final id = await db.insert('supermarkets', {
+      'name': name.trim(),
+      'color': colorValue,
+      'sort_order': (maxOrder ?? -1) + 1,
+    });
+    return Supermarket(
+      id: id,
+      name: name.trim(),
+      colorValue: colorValue,
+      sortOrder: (maxOrder ?? -1) + 1,
+    );
+  }
+
+  Future<void> updateSupermarket(Supermarket store) async {
+    final id = store.id;
+    if (id == null) return;
+    final db = await _database;
+    final existing = await db.query(
+      'supermarkets',
+      where: 'id = ?',
+      whereArgs: [id],
+      limit: 1,
+    );
+    if (existing.isEmpty) return;
+    final oldName = existing.first['name']! as String;
+    await db.update(
+      'supermarkets',
+      {
+        'name': store.name.trim(),
+        'color': store.colorValue,
+        'sort_order': store.sortOrder,
+      },
+      where: 'id = ?',
+      whereArgs: [id],
+    );
+    if (oldName != store.name.trim()) {
+      await db.update(
+        'products',
+        {'supermarket': store.name.trim()},
+        where: 'supermarket = ?',
+        whereArgs: [oldName],
+      );
+      await db.update(
+        'shops',
+        {'supermarket': store.name.trim()},
+        where: 'supermarket = ?',
+        whereArgs: [oldName],
+      );
+    }
+  }
+
+  Future<void> deleteSupermarket(int id) async {
+    final db = await _database;
+    await db.delete('supermarkets', where: 'id = ?', whereArgs: [id]);
+  }
+
+  Future<List<Map<String, Object?>>> dumpTable(String table) async {
+    final db = await _database;
+    return db.query(table, orderBy: 'id ASC');
+  }
+
+  Future<String> writeImageBytes(String relativePath, List<int> bytes) async {
+    final dir = await getApplicationDocumentsDirectory();
+    final dest = File(p.join(dir.path, relativePath));
+    await dest.parent.create(recursive: true);
+    await dest.writeAsBytes(bytes, flush: true);
+    return dest.path;
+  }
+
+  Future<void> clearImageFolders() async {
+    final dir = await getApplicationDocumentsDirectory();
+    for (final name in ['receipts', 'products']) {
+      final folder = Directory(p.join(dir.path, name));
+      if (await folder.exists()) {
+        await folder.delete(recursive: true);
+      }
+    }
+  }
+
+  Future<void> replaceAllData({
+    required List<Map<String, Object?>> supermarkets,
+    required List<Map<String, Object?>> products,
+    required List<Map<String, Object?>> shops,
+    required List<Map<String, Object?>> shopItems,
+    required bool darkMode,
+  }) async {
+    final db = await _database;
+    await db.transaction((txn) async {
+      await txn.delete('shop_items');
+      await txn.delete('shops');
+      await txn.delete('products');
+      await txn.delete('supermarkets');
+      await txn.delete('app_settings');
+
+      for (final row in supermarkets) {
+        await txn.insert('supermarkets', _sqlRow(row, _supermarketColumns));
+      }
+      for (final row in products) {
+        await txn.insert('products', _sqlRow(row, _productColumns));
+      }
+      for (final row in shops) {
+        await txn.insert('shops', _sqlRow(row, _shopColumns));
+      }
+      for (final row in shopItems) {
+        await txn.insert('shop_items', _sqlRow(row, _shopItemColumns));
+      }
+      await txn.insert('app_settings', {
+        'key': 'dark_mode',
+        'value': darkMode ? '1' : '0',
+      });
+
+      await _resetSequence(txn, 'supermarkets');
+      await _resetSequence(txn, 'products');
+      await _resetSequence(txn, 'shops');
+      await _resetSequence(txn, 'shop_items');
     });
   }
 
-  Future<List<Product>> getAll() async {
-    final db = await _database;
-    final rows = await db.query(
-      'products',
-      orderBy: 'name COLLATE NOCASE ASC',
-    );
-    return rows.map(Product.fromMap).toList();
+  static const _supermarketColumns = {
+    'id',
+    'name',
+    'color',
+    'sort_order',
+  };
+  static const _productColumns = {
+    'id',
+    'name',
+    'normalized_name',
+    'last_price',
+    'times_seen',
+    'favourite',
+    'image_path',
+    'supermarket',
+    'notes',
+    'category',
+    'created_at',
+    'updated_at',
+  };
+  static const _shopColumns = {
+    'id',
+    'supermarket',
+    'shopped_at',
+    'receipt_image_path',
+    'total',
+    'created_at',
+  };
+  static const _shopItemColumns = {
+    'id',
+    'shop_id',
+    'product_id',
+    'name',
+    'price',
+    'quantity',
+    'unit_price',
+  };
+
+  Map<String, Object?> _sqlRow(
+    Map<String, Object?> source,
+    Set<String> columns,
+  ) {
+    final row = <String, Object?>{};
+    for (final column in columns) {
+      if (!source.containsKey(column)) continue;
+      row[column] = _sqlValue(source[column]);
+    }
+    return row;
+  }
+
+  Object? _sqlValue(Object? value) {
+    if (value == null) return null;
+    if (value is bool) return value ? 1 : 0;
+    if (value is int) return value;
+    if (value is double) {
+      if (value == value.roundToDouble()) return value.toInt();
+      return value;
+    }
+    if (value is num) return value.toDouble();
+    return value.toString();
+  }
+
+  Future<void> _resetSequence(DatabaseExecutor db, String table) async {
+    try {
+      final max = Sqflite.firstIntValue(
+        await db.rawQuery('SELECT MAX(id) FROM $table'),
+      );
+      await db.delete('sqlite_sequence', where: 'name = ?', whereArgs: [table]);
+      if (max != null) {
+        await db.insert('sqlite_sequence', {'name': table, 'seq': max});
+      }
+    } catch (_) {
+      // sqlite_sequence is missing on some empty databases.
+    }
   }
 }

lib/shop_detail_screen.dart

@@ -0,0 +1,158 @@
+/// One shopping trip: receipt photo, supermarket, products and costs.
+library;
+
+import 'dart:io';
+
+import 'package:flutter/material.dart';
+
+import 'models/shop.dart';
+import 'product_detail_screen.dart';
+import 'services/product_repository.dart';
+import 'utils/dates.dart';
+import 'utils/money.dart';
+
+class ShopDetailScreen extends StatefulWidget {
+  const ShopDetailScreen({
+    super.key,
+    required this.repository,
+    required this.shopId,
+  });
+
+  final ProductRepository repository;
+  final int shopId;
+
+  @override
+  State<ShopDetailScreen> createState() => _ShopDetailScreenState();
+}
+
+class _ShopDetailScreenState extends State<ShopDetailScreen> {
+  late Future<({Shop shop, List<ShopItem> items})> _future;
+
+  @override
+  void initState() {
+    super.initState();
+    _future = _load();
+  }
+
+  Future<({Shop shop, List<ShopItem> items})> _load() async {
+    final shop = await widget.repository.getShop(widget.shopId);
+    if (shop == null) {
+      throw StateError('Shop not found');
+    }
+    final items = await widget.repository.getShopItems(widget.shopId);
+    return (shop: shop, items: items);
+  }
+
+  Future<void> _openReceipt(File file) async {
+    await showDialog<void>(
+      context: context,
+      builder: (context) {
+        return Dialog(
+          insetPadding: const EdgeInsets.all(16),
+          child: InteractiveViewer(
+            child: Image.file(file, fit: BoxFit.contain),
+          ),
+        );
+      },
+    );
+  }
+
+  Future<void> _openProduct(int productId) async {
+    await Navigator.of(context).push<void>(
+      MaterialPageRoute(
+        builder: (_) => ProductDetailScreen(
+          repository: widget.repository,
+          productId: productId,
+        ),
+      ),
+    );
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = Theme.of(context);
+
+    return Scaffold(
+      appBar: AppBar(title: const Text('Shopping trip')),
+      body: FutureBuilder(
+        future: _future,
+        builder: (context, snapshot) {
+          if (snapshot.hasError) {
+            return Center(
+              child: Text(
+                'Could not load this trip.',
+                style: theme.textTheme.bodyLarge,
+              ),
+            );
+          }
+          if (!snapshot.hasData) {
+            return const Center(child: CircularProgressIndicator());
+          }
+
+          final shop = snapshot.data!.shop;
+          final items = snapshot.data!.items;
+          final receipt = shop.receiptImagePath;
+          final receiptFile =
+              receipt == null ? null : File(receipt);
+          final hasReceipt =
+              receiptFile != null && receiptFile.existsSync();
+
+          return ListView(
+            padding: const EdgeInsets.fromLTRB(16, 8, 16, 32),
+            children: [
+              Text(shop.supermarket, style: theme.textTheme.headlineMedium),
+              const SizedBox(height: 4),
+              Text(
+                formatDate(shop.shoppedAt),
+                style: theme.textTheme.bodyLarge,
+              ),
+              if (hasReceipt) ...[
+                const SizedBox(height: 16),
+                GestureDetector(
+                  onTap: () => _openReceipt(receiptFile),
+                  child: ClipRRect(
+                    borderRadius: BorderRadius.circular(16),
+                    child: Image.file(
+                      receiptFile,
+                      height: 180,
+                      width: double.infinity,
+                      fit: BoxFit.cover,
+                      cacheWidth: 900,
+                    ),
+                  ),
+                ),
+              ],
+              const SizedBox(height: 24),
+              Text('Products', style: theme.textTheme.titleMedium),
+              const SizedBox(height: 8),
+              for (final item in items)
+                ListTile(
+                  contentPadding: EdgeInsets.zero,
+                  title: Text(item.name),
+                  subtitle: item.quantity == null
+                      ? null
+                      : Text(
+                          '${item.quantity} × ${formatEuro(item.unitPrice ?? 0)}',
+                        ),
+                  trailing: Text(
+                    formatEuro(item.price),
+                    style: theme.textTheme.titleMedium,
+                  ),
+                  onTap: () => _openProduct(item.productId),
+                ),
+              const Divider(),
+              ListTile(
+                contentPadding: EdgeInsets.zero,
+                title: Text('Total', style: theme.textTheme.titleMedium),
+                trailing: Text(
+                  formatEuro(shop.total),
+                  style: theme.textTheme.titleLarge,
+                ),
+              ),
+            ],
+          );
+        },
+      ),
+    );
+  }
+}

lib/shop_log_screen.dart

@@ -0,0 +1,159 @@
+/// Log of saved shopping trips.
+library;
+
+import 'dart:io';
+
+import 'package:flutter/material.dart';
+
+import 'models/shop.dart';
+import 'services/app_settings.dart';
+import 'services/product_repository.dart';
+import 'shop_detail_screen.dart';
+import 'utils/dates.dart';
+import 'utils/money.dart';
+import 'widgets/settings_button.dart';
+import 'widgets/store_tag.dart';
+
+class ShopLogScreen extends StatefulWidget {
+  const ShopLogScreen({super.key, required this.repository});
+
+  final ProductRepository repository;
+
+  @override
+  State<ShopLogScreen> createState() => _ShopLogScreenState();
+}
+
+class _ShopLogScreenState extends State<ShopLogScreen> {
+  late Future<List<Shop>> _future;
+
+  @override
+  void initState() {
+    super.initState();
+    _future = widget.repository.getShops();
+  }
+
+  void _reload() {
+    setState(() => _future = widget.repository.getShops());
+  }
+
+  Future<void> _openShop(Shop shop) async {
+    await Navigator.of(context).push<void>(
+      MaterialPageRoute(
+        builder: (_) => ShopDetailScreen(
+          repository: widget.repository,
+          shopId: shop.id,
+        ),
+      ),
+    );
+    if (mounted) _reload();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = Theme.of(context);
+    final stores = SettingsScope.maybeOf(context)?.supermarkets ?? const [];
+
+    return Scaffold(
+      appBar: AppBar(
+        title: const Text('Shop log'),
+        actions: const [SettingsButton()],
+      ),
+      body: FutureBuilder<List<Shop>>(
+        future: _future,
+        builder: (context, snapshot) {
+          if (snapshot.hasError) {
+            return Center(
+              child: Text(
+                'Could not load the shop log.',
+                style: theme.textTheme.bodyLarge,
+              ),
+            );
+          }
+          if (!snapshot.hasData) {
+            return const Center(child: CircularProgressIndicator());
+          }
+
+          final shops = snapshot.data!;
+          if (shops.isEmpty) {
+            return Center(
+              child: Text(
+                'Scan a receipt to log a shopping trip.',
+                textAlign: TextAlign.center,
+                style: theme.textTheme.bodyLarge,
+              ),
+            );
+          }
+
+          return ListView.separated(
+            padding: const EdgeInsets.fromLTRB(8, 8, 8, 16),
+            itemCount: shops.length,
+            separatorBuilder: (_, _) => const SizedBox(height: 4),
+            itemBuilder: (context, index) {
+              final shop = shops[index];
+              final count = shop.itemCount;
+              return ListTile(
+                leading: _ReceiptThumb(path: shop.receiptImagePath),
+                title: Align(
+                  alignment: Alignment.centerLeft,
+                  child: StoreTag(name: shop.supermarket, stores: stores),
+                ),
+                subtitle: Text(
+                  [
+                    formatDate(shop.shoppedAt),
+                    count == 1 ? '1 product' : '$count products',
+                  ].join(' · '),
+                ),
+                trailing: Text(
+                  formatEuro(shop.total),
+                  style: theme.textTheme.titleMedium,
+                ),
+                onTap: () => _openShop(shop),
+              );
+            },
+          );
+        },
+      ),
+    );
+  }
+}
+
+class _ReceiptThumb extends StatelessWidget {
+  const _ReceiptThumb({this.path});
+
+  final String? path;
+
+  @override
+  Widget build(BuildContext context) {
+    final file = path == null ? null : File(path!);
+    final hasFile = file != null && file.existsSync();
+    final scheme = Theme.of(context).colorScheme;
+
+    return ClipRRect(
+      borderRadius: BorderRadius.circular(12),
+      child: SizedBox(
+        width: 48,
+        height: 48,
+        child: hasFile
+            ? Image.file(
+                file,
+                fit: BoxFit.cover,
+                cacheWidth: 144,
+                errorBuilder: (_, _, _) => ColoredBox(
+                  color: scheme.secondaryContainer,
+                  child: Icon(
+                    Icons.receipt_long_outlined,
+                    color: scheme.onSecondaryContainer,
+                  ),
+                ),
+              )
+            : ColoredBox(
+                color: scheme.secondaryContainer,
+                child: Icon(
+                  Icons.receipt_long_outlined,
+                  color: scheme.onSecondaryContainer,
+                ),
+              ),
+      ),
+    );
+  }
+}

lib/utils/categories.dart

@@ -0,0 +1,29 @@
+/// Grocery categories a product can be assigned to.
+library;
+
+const List<String> kDefaultCategories = [
+  'Fruit & vegetables',
+  'Dairy & eggs',
+  'Meat & fish',
+  'Bread & bakery',
+  'Pantry',
+  'Drinks',
+  'Frozen',
+  'Snacks',
+  'Household',
+  'Personal care',
+];
+
+List<String> mergeCategories(Iterable<String> used) {
+  final seen = <String>{};
+  final result = <String>[];
+  for (final name in [...kDefaultCategories, ...used]) {
+    final trimmed = name.trim();
+    if (trimmed.isEmpty) continue;
+    final key = trimmed.toLowerCase();
+    if (seen.contains(key)) continue;
+    seen.add(key);
+    result.add(trimmed);
+  }
+  return result;
+}

lib/utils/dates.dart

@@ -0,0 +1,20 @@
+/// Date formatting for shop log and product history.
+library;
+
+const _months = [
+  'Jan',
+  'Feb',
+  'Mar',
+  'Apr',
+  'May',
+  'Jun',
+  'Jul',
+  'Aug',
+  'Sep',
+  'Oct',
+  'Nov',
+  'Dec',
+];
+
+String formatDate(DateTime date) =>
+    '${date.day} ${_months[date.month - 1]} ${date.year}';

lib/utils/fuzzy.dart

@@ -0,0 +1,40 @@
+/// Lightweight fuzzy matching for product search.
+library;
+
+String _normalize(String value) =>
+    value.trim().toLowerCase().replaceAll(RegExp(r'\s+'), ' ');
+
+/// True when [query] fuzzily matches [text].
+bool fuzzyMatch(String query, String text) {
+  final q = _normalize(query);
+  if (q.isEmpty) return true;
+  final t = _normalize(text);
+  if (t.contains(q)) return true;
+
+  for (final word in q.split(' ')) {
+    if (word.isEmpty) continue;
+    if (!t.contains(word) && !_subsequence(word, t)) return false;
+  }
+  if (q.contains(' ')) return true;
+  return _subsequence(q, t);
+}
+
+/// Higher is better. Null when [query] does not match.
+int? fuzzyScore(String query, String text) {
+  final q = _normalize(query);
+  if (q.isEmpty) return 0;
+  final t = _normalize(text);
+  if (t == q) return 1000;
+  if (t.startsWith(q)) return 800;
+  if (t.contains(q)) return 600 - t.indexOf(q);
+  if (!fuzzyMatch(q, t)) return null;
+  return 200 - (t.length - q.length).abs().clamp(0, 150);
+}
+
+bool _subsequence(String query, String text) {
+  var i = 0;
+  for (var c = 0; c < text.length && i < query.length; c++) {
+    if (text.codeUnitAt(c) == query.codeUnitAt(i)) i++;
+  }
+  return i == query.length;
+}

lib/utils/supermarkets.dart

@@ -0,0 +1,99 @@
+/// Known Dutch supermarket names, default colors, and OCR detection.
+library;
+
+import '../models/supermarket.dart';
+
+const String kOtherSupermarket = 'Other';
+
+final List<Supermarket> kDefaultSupermarkets = [
+  const Supermarket(name: 'Albert Heijn', colorValue: 0xFF00A0E2, sortOrder: 0),
+  const Supermarket(name: 'Jumbo', colorValue: 0xFFEEC21B, sortOrder: 1),
+  const Supermarket(name: 'Lidl', colorValue: 0xFF0050AA, sortOrder: 2),
+  const Supermarket(name: 'Aldi', colorValue: 0xFF00205B, sortOrder: 3),
+  const Supermarket(name: 'Plus', colorValue: 0xFF6EC31E, sortOrder: 4),
+  const Supermarket(name: 'Dirk', colorValue: 0xFFE30613, sortOrder: 5),
+  const Supermarket(name: 'Coop', colorValue: 0xFFE30613, sortOrder: 6),
+  const Supermarket(name: 'SPAR', colorValue: 0xFF009640, sortOrder: 7),
+  const Supermarket(name: 'Nettorama', colorValue: 0xFFE87722, sortOrder: 8),
+  const Supermarket(name: 'Hoogvliet', colorValue: 0xFFD32F2F, sortOrder: 9),
+  const Supermarket(name: 'Picnic', colorValue: 0xFFE31C5F, sortOrder: 10),
+  const Supermarket(name: kOtherSupermarket, colorValue: 0xFF78909C, sortOrder: 11),
+];
+
+const Map<String, List<String>> kSupermarketAliases = {
+  'Albert Heijn': ['ALBERT HEIJN', 'AH TO GO', 'AH XL'],
+  'Jumbo': ['JUMBO'],
+  'Lidl': ['LIDL'],
+  'Aldi': ['ALDI'],
+  'Plus': ['PLUS'],
+  'Dirk': ['DIRK'],
+  'Coop': ['COOP'],
+  'SPAR': ['SPAR'],
+  'Nettorama': ['NETTORAMA'],
+  'Hoogvliet': ['HOOGVLIET'],
+  'Picnic': ['PICNIC'],
+};
+
+/// Names used before settings were user-editable.
+const List<String> kSupermarkets = [
+  'Albert Heijn',
+  'Jumbo',
+  'Lidl',
+  'Aldi',
+  'Plus',
+  'Dirk',
+  'Coop',
+  'SPAR',
+  'Nettorama',
+  'Hoogvliet',
+  'Picnic',
+  'Other',
+];
+
+/// Returns a supermarket name if it appears in [rawText].
+String? detectSupermarket(
+  String rawText, {
+  Iterable<String> names = const [],
+}) {
+  final upper = rawText.toUpperCase();
+  final extra = names
+      .map((name) => name.trim())
+      .where((name) => name.isNotEmpty && name != kOtherSupermarket)
+      .toList()
+    ..sort((a, b) => b.length.compareTo(a.length));
+
+  for (final name in extra) {
+    if (RegExp('\\b${RegExp.escape(name)}\\b', caseSensitive: false)
+        .hasMatch(rawText)) {
+      return name;
+    }
+  }
+
+  for (final entry in kSupermarketAliases.entries) {
+    for (final alias in entry.value) {
+      if (RegExp('\\b${RegExp.escape(alias)}\\b').hasMatch(upper)) {
+        return _canonicalName(entry.key, extra);
+      }
+    }
+  }
+
+  if (RegExp(r'\bAH\b').hasMatch(upper)) {
+    return _canonicalName('Albert Heijn', extra);
+  }
+  return null;
+}
+
+String _canonicalName(String fallback, List<String> names) {
+  for (final name in names) {
+    if (name.toUpperCase() == fallback.toUpperCase()) return name;
+  }
+  return fallback;
+}
+
+Supermarket? supermarketByName(Iterable<Supermarket> stores, String? name) {
+  if (name == null || name.isEmpty) return null;
+  for (final store in stores) {
+    if (store.name.toLowerCase() == name.toLowerCase()) return store;
+  }
+  return null;
+}

lib/widgets/price_chart.dart

@@ -0,0 +1,159 @@
+/// Simple line chart of unit prices over time.
+library;
+
+import 'package:flutter/material.dart';
+
+import '../models/purchase.dart';
+import '../utils/dates.dart';
+import '../utils/money.dart';
+
+class PriceChart extends StatelessWidget {
+  const PriceChart({super.key, required this.purchases});
+
+  final List<Purchase> purchases;
+
+  @override
+  Widget build(BuildContext context) {
+    if (purchases.isEmpty) {
+      return const SizedBox.shrink();
+    }
+
+    final points = purchases.reversed.toList();
+    final theme = Theme.of(context);
+
+    return Column(
+      crossAxisAlignment: CrossAxisAlignment.stretch,
+      children: [
+        SizedBox(
+          height: 160,
+          child: CustomPaint(
+            painter: _PriceChartPainter(
+              prices: [
+                for (final purchase in points) purchase.unitOrLinePrice,
+              ],
+              lineColor: theme.colorScheme.primary,
+              fillColor: theme.colorScheme.primary.withValues(alpha: 0.12),
+              gridColor: theme.colorScheme.outlineVariant,
+              labelColor: theme.colorScheme.onSurfaceVariant,
+            ),
+            child: const SizedBox.expand(),
+          ),
+        ),
+        const SizedBox(height: 4),
+        Row(
+          mainAxisAlignment: MainAxisAlignment.spaceBetween,
+          children: [
+            Text(
+              formatDate(points.first.boughtAt),
+              style: theme.textTheme.labelMedium,
+            ),
+            Text(
+              formatDate(points.last.boughtAt),
+              style: theme.textTheme.labelMedium,
+            ),
+          ],
+        ),
+        const SizedBox(height: 4),
+        Text(
+          'Latest ${formatEuro(points.last.unitOrLinePrice)}',
+          style: theme.textTheme.labelMedium,
+        ),
+      ],
+    );
+  }
+}
+
+class _PriceChartPainter extends CustomPainter {
+  _PriceChartPainter({
+    required this.prices,
+    required this.lineColor,
+    required this.fillColor,
+    required this.gridColor,
+    required this.labelColor,
+  });
+
+  final List<double> prices;
+  final Color lineColor;
+  final Color fillColor;
+  final Color gridColor;
+  final Color labelColor;
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    final minPrice = prices.reduce((a, b) => a < b ? a : b);
+    final maxPrice = prices.reduce((a, b) => a > b ? a : b);
+    final span = (maxPrice - minPrice).abs() < 0.01 ? 1.0 : maxPrice - minPrice;
+    const left = 36.0;
+    const right = 8.0;
+    const top = 12.0;
+    const bottom = 8.0;
+    final chart = Rect.fromLTRB(left, top, size.width - right, size.height - bottom);
+
+    final gridPaint = Paint()
+      ..color = gridColor
+      ..strokeWidth = 1;
+    for (var i = 0; i < 3; i++) {
+      final y = chart.top + chart.height * i / 2;
+      canvas.drawLine(Offset(chart.left, y), Offset(chart.right, y), gridPaint);
+    }
+
+    final path = Path();
+    final fill = Path();
+    Offset? last;
+    for (var i = 0; i < prices.length; i++) {
+      final x = prices.length == 1
+          ? chart.center.dx
+          : chart.left + chart.width * i / (prices.length - 1);
+      final y = chart.bottom - chart.height * ((prices[i] - minPrice) / span);
+      final point = Offset(x, y);
+      last = point;
+      if (i == 0) {
+        path.moveTo(x, y);
+        fill.moveTo(x, chart.bottom);
+        fill.lineTo(x, y);
+      } else {
+        path.lineTo(x, y);
+        fill.lineTo(x, y);
+      }
+    }
+    if (last != null) {
+      fill.lineTo(last.dx, chart.bottom);
+      fill.close();
+    }
+
+    canvas.drawPath(fill, Paint()..color = fillColor);
+    canvas.drawPath(
+      path,
+      Paint()
+        ..color = lineColor
+        ..style = PaintingStyle.stroke
+        ..strokeWidth = 2.5
+        ..strokeCap = StrokeCap.round
+        ..strokeJoin = StrokeJoin.round,
+    );
+
+    final dot = Paint()..color = lineColor;
+    for (var i = 0; i < prices.length; i++) {
+      final x = prices.length == 1
+          ? chart.center.dx
+          : chart.left + chart.width * i / (prices.length - 1);
+      final y = chart.bottom - chart.height * ((prices[i] - minPrice) / span);
+      canvas.drawCircle(Offset(x, y), 3.5, dot);
+    }
+
+    final labels = [maxPrice, (minPrice + maxPrice) / 2, minPrice];
+    final textStyle = TextStyle(color: labelColor, fontSize: 10);
+    for (var i = 0; i < labels.length; i++) {
+      final tp = TextPainter(
+        text: TextSpan(text: labels[i].toStringAsFixed(2), style: textStyle),
+        textDirection: TextDirection.ltr,
+      )..layout(maxWidth: left - 4);
+      final y = chart.top + chart.height * i / 2 - tp.height / 2;
+      tp.paint(canvas, Offset(0, y));
+    }
+  }
+
+  @override
+  bool shouldRepaint(covariant _PriceChartPainter oldDelegate) =>
+      oldDelegate.prices != prices || oldDelegate.lineColor != lineColor;
+}

lib/widgets/product_image.dart

@@ -0,0 +1,80 @@
+/// Thumbnail or letter avatar for a product.
+library;
+
+import 'dart:io';
+
+import 'package:flutter/material.dart';
+
+class ProductImage extends StatelessWidget {
+  const ProductImage({
+    super.key,
+    required this.name,
+    this.path,
+    this.size = 48,
+  });
+
+  final String name;
+  final String? path;
+  final double size;
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = Theme.of(context);
+    final file = path == null ? null : File(path!);
+    final hasFile = file != null && file.existsSync();
+
+    return ClipRRect(
+      borderRadius: BorderRadius.circular(size / 4),
+      child: SizedBox(
+        width: size,
+        height: size,
+        child: hasFile
+            ? Image.file(
+                file,
+                fit: BoxFit.cover,
+                cacheWidth: (size * 3).round(),
+                errorBuilder: (_, _, _) => _LetterAvatar(
+                  name: name,
+                  size: size,
+                  colorScheme: theme.colorScheme,
+                ),
+              )
+            : _LetterAvatar(
+                name: name,
+                size: size,
+                colorScheme: theme.colorScheme,
+              ),
+      ),
+    );
+  }
+}
+
+class _LetterAvatar extends StatelessWidget {
+  const _LetterAvatar({
+    required this.name,
+    required this.size,
+    required this.colorScheme,
+  });
+
+  final String name;
+  final double size;
+  final ColorScheme colorScheme;
+
+  @override
+  Widget build(BuildContext context) {
+    final trimmed = name.trim();
+    final letter = trimmed.isEmpty ? '?' : trimmed.substring(0, 1).toUpperCase();
+    return ColoredBox(
+      color: colorScheme.secondaryContainer,
+      child: Center(
+        child: Text(
+          letter,
+          style: Theme.of(context).textTheme.titleMedium?.copyWith(
+            color: colorScheme.onSecondaryContainer,
+            fontSize: size * 0.4,
+          ),
+        ),
+      ),
+    );
+  }
+}

lib/widgets/settings_button.dart

@@ -0,0 +1,372 @@
+/// Gear that opens the settings sheet.
+library;
+
+import 'package:flutter/material.dart';
+
+import '../models/supermarket.dart';
+import '../services/app_settings.dart';
+import '../services/backup_service.dart';
+
+class SettingsButton extends StatelessWidget {
+  const SettingsButton({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return IconButton(
+      tooltip: 'Settings',
+      onPressed: () => showSettingsSheet(context),
+      icon: const Icon(Icons.settings_outlined),
+    );
+  }
+}
+
+Future<void> showSettingsSheet(BuildContext context) {
+  return showModalBottomSheet<void>(
+    context: context,
+    isScrollControlled: true,
+    showDragHandle: true,
+    builder: (context) {
+      return const _SettingsSheet();
+    },
+  );
+}
+
+class _SettingsSheet extends StatefulWidget {
+  const _SettingsSheet();
+
+  @override
+  State<_SettingsSheet> createState() => _SettingsSheetState();
+}
+
+class _SettingsSheetState extends State<_SettingsSheet> {
+  bool _busy = false;
+
+  Future<void> _export(AppSettings settings) async {
+    setState(() => _busy = true);
+    try {
+      final shared = await BackupService(settings.repository).exportBackup();
+      if (!mounted) return;
+      if (shared) {
+        ScaffoldMessenger.of(context).showSnackBar(
+          const SnackBar(content: Text('Backup ready.')),
+        );
+      }
+    } catch (_) {
+      if (!mounted) return;
+      ScaffoldMessenger.of(context).showSnackBar(
+        const SnackBar(content: Text('Could not export the backup.')),
+      );
+    } finally {
+      if (mounted) setState(() => _busy = false);
+    }
+  }
+
+  Future<void> _import(AppSettings settings) async {
+    final confirmed = await showDialog<bool>(
+      context: context,
+      builder: (context) {
+        return AlertDialog(
+          title: const Text('Import backup?'),
+          content: const Text(
+            'This replaces all products, shopping trips, photos, and settings on this device.',
+          ),
+          actions: [
+            TextButton(
+              onPressed: () => Navigator.pop(context, false),
+              child: const Text('Cancel'),
+            ),
+            FilledButton(
+              onPressed: () => Navigator.pop(context, true),
+              child: const Text('Import'),
+            ),
+          ],
+        );
+      },
+    );
+    if (confirmed != true || !mounted) return;
+
+    setState(() => _busy = true);
+    try {
+      final imported = await BackupService(settings.repository).importBackup();
+      if (!mounted) return;
+      if (imported) {
+        await settings.reload();
+        if (!mounted) return;
+        ScaffoldMessenger.of(context).showSnackBar(
+          const SnackBar(content: Text('Backup imported.')),
+        );
+      }
+    } catch (_) {
+      if (!mounted) return;
+      ScaffoldMessenger.of(context).showSnackBar(
+        const SnackBar(content: Text('Could not import this backup.')),
+      );
+    } finally {
+      if (mounted) setState(() => _busy = false);
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final settings = SettingsScope.of(context);
+    final bottom = MediaQuery.viewInsetsOf(context).bottom;
+
+    return ListenableBuilder(
+      listenable: settings,
+      builder: (context, _) {
+        return Padding(
+          padding: EdgeInsets.fromLTRB(16, 0, 16, 16 + bottom),
+          child: SizedBox(
+            height: MediaQuery.sizeOf(context).height * 0.75,
+            child: Column(
+              crossAxisAlignment: CrossAxisAlignment.stretch,
+              children: [
+                Text('Settings', style: Theme.of(context).textTheme.titleLarge),
+                const SizedBox(height: 8),
+                SwitchListTile(
+                  contentPadding: EdgeInsets.zero,
+                  title: const Text('Dark mode'),
+                  value: settings.darkMode,
+                  onChanged: _busy ? null : settings.setDarkMode,
+                ),
+                Text('Backup', style: Theme.of(context).textTheme.titleMedium),
+                Text(
+                  'Save everything to a JSON file, or replace this device from a backup.',
+                  style: Theme.of(context).textTheme.bodyMedium,
+                ),
+                const SizedBox(height: 8),
+                Row(
+                  children: [
+                    Expanded(
+                      child: OutlinedButton.icon(
+                        onPressed: _busy ? null : () => _export(settings),
+                        icon: const Icon(Icons.file_upload_outlined),
+                        label: const Text('Export'),
+                      ),
+                    ),
+                    const SizedBox(width: 8),
+                    Expanded(
+                      child: OutlinedButton.icon(
+                        onPressed: _busy ? null : () => _import(settings),
+                        icon: const Icon(Icons.file_download_outlined),
+                        label: const Text('Import'),
+                      ),
+                    ),
+                  ],
+                ),
+                if (_busy) ...[
+                  const SizedBox(height: 8),
+                  const LinearProgressIndicator(),
+                ],
+                const SizedBox(height: 16),
+                Text(
+                  'Supermarkets',
+                  style: Theme.of(context).textTheme.titleMedium,
+                ),
+                Text(
+                  'Name and color used as tags on products.',
+                  style: Theme.of(context).textTheme.bodyMedium,
+                ),
+                const SizedBox(height: 8),
+                Expanded(
+                  child: ListView(
+                    children: [
+                      for (final store in settings.supermarkets)
+                        _StoreRow(
+                          store: store,
+                          onEdit: _busy
+                              ? () {}
+                              : () => _editStore(context, settings, store),
+                          onDelete: _busy || store.id == null
+                              ? null
+                              : () => settings.deleteSupermarket(store.id!),
+                        ),
+                    ],
+                  ),
+                ),
+                const SizedBox(height: 8),
+                OutlinedButton.icon(
+                  onPressed: _busy
+                      ? null
+                      : () => _editStore(context, settings, null),
+                  icon: const Icon(Icons.add),
+                  label: const Text('Add supermarket'),
+                ),
+              ],
+            ),
+          ),
+        );
+      },
+    );
+  }
+
+  Future<void> _editStore(
+    BuildContext context,
+    AppSettings settings,
+    Supermarket? existing,
+  ) async {
+    final result = await showDialog<Supermarket>(
+      context: context,
+      builder: (context) => _StoreEditDialog(store: existing),
+    );
+    if (result == null) return;
+    if (existing == null) {
+      try {
+        await settings.addSupermarket(result.name, result.colorValue);
+      } catch (_) {
+        if (context.mounted) {
+          ScaffoldMessenger.of(context).showSnackBar(
+            const SnackBar(content: Text('That supermarket already exists.')),
+          );
+        }
+      }
+    } else {
+      await settings.updateSupermarket(
+        existing.copyWith(name: result.name, colorValue: result.colorValue),
+      );
+    }
+  }
+}
+
+class _StoreRow extends StatelessWidget {
+  const _StoreRow({
+    required this.store,
+    required this.onEdit,
+    this.onDelete,
+  });
+
+  final Supermarket store;
+  final VoidCallback onEdit;
+  final VoidCallback? onDelete;
+
+  @override
+  Widget build(BuildContext context) {
+    final onColor = store.color.computeLuminance() > 0.55
+        ? Colors.black87
+        : Colors.white;
+
+    return ListTile(
+      contentPadding: EdgeInsets.zero,
+      leading: CircleAvatar(
+        backgroundColor: store.color,
+        child: Text(
+          store.name.isEmpty ? '?' : store.name.substring(0, 1),
+          style: TextStyle(color: onColor, fontWeight: FontWeight.w700),
+        ),
+      ),
+      title: Text(store.name),
+      trailing: Row(
+        mainAxisSize: MainAxisSize.min,
+        children: [
+          IconButton(
+            tooltip: 'Edit',
+            onPressed: onEdit,
+            icon: const Icon(Icons.edit_outlined),
+          ),
+          IconButton(
+            tooltip: 'Delete',
+            onPressed: onDelete,
+            icon: const Icon(Icons.delete_outline),
+          ),
+        ],
+      ),
+    );
+  }
+}
+
+class _StoreEditDialog extends StatefulWidget {
+  const _StoreEditDialog({this.store});
+
+  final Supermarket? store;
+
+  @override
+  State<_StoreEditDialog> createState() => _StoreEditDialogState();
+}
+
+class _StoreEditDialogState extends State<_StoreEditDialog> {
+  late final TextEditingController _name;
+  late int _color;
+
+  @override
+  void initState() {
+    super.initState();
+    _name = TextEditingController(text: widget.store?.name ?? '');
+    _color = widget.store?.colorValue ?? kStoreColorPalette.first;
+  }
+
+  @override
+  void dispose() {
+    _name.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return AlertDialog(
+      title: Text(widget.store == null ? 'Add supermarket' : 'Edit supermarket'),
+      content: Column(
+        mainAxisSize: MainAxisSize.min,
+        children: [
+          TextField(
+            controller: _name,
+            textCapitalization: TextCapitalization.words,
+            decoration: const InputDecoration(labelText: 'Name'),
+            autofocus: widget.store == null,
+          ),
+          const SizedBox(height: 16),
+          Align(
+            alignment: Alignment.centerLeft,
+            child: Text('Color', style: Theme.of(context).textTheme.titleMedium),
+          ),
+          const SizedBox(height: 8),
+          Wrap(
+            spacing: 8,
+            runSpacing: 8,
+            children: [
+              for (final value in kStoreColorPalette)
+                GestureDetector(
+                  onTap: () => setState(() => _color = value),
+                  child: Container(
+                    width: 32,
+                    height: 32,
+                    decoration: BoxDecoration(
+                      color: Color(value),
+                      shape: BoxShape.circle,
+                      border: Border.all(
+                        color: _color == value
+                            ? Theme.of(context).colorScheme.onSurface
+                            : Colors.transparent,
+                        width: 2,
+                      ),
+                    ),
+                  ),
+                ),
+            ],
+          ),
+        ],
+      ),
+      actions: [
+        TextButton(
+          onPressed: () => Navigator.pop(context),
+          child: const Text('Cancel'),
+        ),
+        FilledButton(
+          onPressed: () {
+            final name = _name.text.trim();
+            if (name.isEmpty) return;
+            Navigator.pop(
+              context,
+              Supermarket(
+                id: widget.store?.id,
+                name: name,
+                colorValue: _color,
+                sortOrder: widget.store?.sortOrder ?? 0,
+              ),
+            );
+          },
+          child: const Text('Save'),
+        ),
+      ],
+    );
+  }
+}

lib/widgets/store_tag.dart

@@ -0,0 +1,67 @@
+/// Colored supermarket chip used in lists and on product pages.
+library;
+
+import 'package:flutter/material.dart';
+
+import '../models/supermarket.dart';
+import '../utils/supermarkets.dart';
+
+class StoreTag extends StatelessWidget {
+  const StoreTag({
+    super.key,
+    required this.name,
+    this.stores = const [],
+    this.compact = false,
+  });
+
+  final String? name;
+  final List<Supermarket> stores;
+  final bool compact;
+
+  @override
+  Widget build(BuildContext context) {
+    final storeName = name?.trim();
+    if (storeName == null || storeName.isEmpty) {
+      return const SizedBox.shrink();
+    }
+
+    final store = supermarketByName(stores, storeName);
+    final color = store?.color ?? const Color(0xFF78909C);
+    final onColor = color.computeLuminance() > 0.55
+        ? Colors.black87
+        : Colors.white;
+
+    return Container(
+      padding: EdgeInsets.symmetric(
+        horizontal: compact ? 6 : 8,
+        vertical: compact ? 2 : 4,
+      ),
+      decoration: BoxDecoration(
+        color: color,
+        borderRadius: BorderRadius.circular(8),
+      ),
+      child: Row(
+        mainAxisSize: MainAxisSize.min,
+        children: [
+          Container(
+            width: compact ? 6 : 8,
+            height: compact ? 6 : 8,
+            decoration: BoxDecoration(
+              color: onColor.withValues(alpha: 0.85),
+              shape: BoxShape.circle,
+            ),
+          ),
+          SizedBox(width: compact ? 4 : 6),
+          Text(
+            storeName,
+            style: Theme.of(context).textTheme.labelMedium?.copyWith(
+              color: onColor,
+              fontWeight: FontWeight.w600,
+              fontSize: compact ? 11 : 12,
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+}

pubspec.lock

@@ -1,6 +1,14 @@
 # Generated by pub
 # See https://dart.dev/tools/pub/glossary#lockfile
 packages:
+  android_file_picker:
+    dependency: transitive
+    description:
+      name: android_file_picker
+      sha256: "1f111ed6bb33724ba782cc86357e3fd97f57051d55fc61adf33dcfc5049a1581"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.0.3"
   args:
     dependency: transitive
     description:
@@ -81,6 +89,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.0.9"
+  dbus:
+    dependency: transitive
+    description:
+      name: dbus
+      sha256: a48d5da28e89bd02196e80d81ed8d7954923d00a0f4a68cc20b575038f023383
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.7.15"
   fake_async:
     dependency: transitive
     description:
@@ -97,6 +113,62 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.2.0"
+  ffi_leak_tracker:
+    dependency: transitive
+    description:
+      name: ffi_leak_tracker
+      sha256: "4093d4ef9ca06ffe2786e73bfb25e22aa92112b9bb4ec941f11e3e6b61489a97"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.1.2"
+  file:
+    dependency: transitive
+    description:
+      name: file
+      sha256: a3b4f84adafef897088c160faf7dfffb7696046cb13ae90b508c2cbc95d3b8d4
+      url: "https://pub.dev"
+    source: hosted
+    version: "7.0.1"
+  file_picker:
+    dependency: "direct main"
+    description:
+      name: file_picker
+      sha256: b7acb5d123cb398f6b4a8a38e43777545254f8fc1fabef3ee11cbbb56aece9c8
+      url: "https://pub.dev"
+    source: hosted
+    version: "12.1.2"
+  file_picker_darwin:
+    dependency: transitive
+    description:
+      name: file_picker_darwin
+      sha256: "6e7cae501d48fd57a27911608db718ebd898e6ccf934bf09e33a8c0d0365bec0"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.0.4"
+  file_picker_linux:
+    dependency: transitive
+    description:
+      name: file_picker_linux
+      sha256: f0f01ed42967b7355f6f25c8b121ea531d1948e2a9b4b44f4b4de8489d7b04ae
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.0.2"
+  file_picker_platform_interface:
+    dependency: transitive
+    description:
+      name: file_picker_platform_interface
+      sha256: "11ef1b5c14d9186b4788cc273dd8d5cb81bca847145060991a28234ff7916fc1"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.2.0"
+  file_picker_web:
+    dependency: transitive
+    description:
+      name: file_picker_web
+      sha256: df472142f63c4557fdfbb375c81454ca1c251491069eefcdc6a866bc12f8750b
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.0.3"
   file_selector_linux:
     dependency: transitive
     description:
@@ -129,6 +201,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.9.3+6"
+  fixnum:
+    dependency: transitive
+    description:
+      name: fixnum
+      sha256: b6dc7065e46c974bc7c5f143080a6764ec7a4be6da1285ececdc37be96de53be
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.1.1"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -432,6 +512,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.3.0"
+  petitparser:
+    dependency: transitive
+    description:
+      name: petitparser
+      sha256: "91bd59303e9f769f108f8df05e371341b15d59e995e6806aefab827b58336675"
+      url: "https://pub.dev"
+    source: hosted
+    version: "7.0.2"
   platform:
     dependency: transitive
     description:
@@ -464,6 +552,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.6.0"
+  share_plus:
+    dependency: "direct main"
+    description:
+      name: share_plus
+      sha256: "34f00f9becd2743c1fb05363d624f9f70d37f7ccdcdda47450bc0b8c9d327b8c"
+      url: "https://pub.dev"
+    source: hosted
+    version: "13.3.0"
+  share_plus_platform_interface:
+    dependency: transitive
+    description:
+      name: share_plus_platform_interface
+      sha256: "365ef7379fc22507256adda3385152942ffce08935452bc972c2e52a0bebae41"
+      url: "https://pub.dev"
+    source: hosted
+    version: "7.2.0"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -573,6 +677,46 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.4.0"
+  url_launcher_linux:
+    dependency: transitive
+    description:
+      name: url_launcher_linux
+      sha256: "10f86fef4c2c43563fa6c211ff9cf757adf4d3ab762c56bd430664a947d70cd0"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.2.3"
+  url_launcher_platform_interface:
+    dependency: transitive
+    description:
+      name: url_launcher_platform_interface
+      sha256: "552f8a1e663569be95a8190206a38187b531910283c3e982193e4f2733f01029"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.3.2"
+  url_launcher_web:
+    dependency: transitive
+    description:
+      name: url_launcher_web
+      sha256: "85c81589622fbc87c1c683aaea164d3604a7777495a79d91e39ffcdec39ddb34"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.4.3"
+  url_launcher_windows:
+    dependency: transitive
+    description:
+      name: url_launcher_windows
+      sha256: "6c5ad3f22cd4c38e089b81963b3cd7bb83b111b2df5dce008bb066162f42e429"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.1.6"
+  uuid:
+    dependency: transitive
+    description:
+      name: uuid
+      sha256: "9b129329f58692f6e6578329498a8fe9fbe98f090beb764ffbb8ee2eadd01dcd"
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.6.0"
   vector_math:
     dependency: transitive
     description:
@@ -597,6 +741,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.1.1"
+  win32:
+    dependency: transitive
+    description:
+      name: win32
+      sha256: a0b93865d5644f11cf6a8c3f6db909f1ec168958b5805f6cc684adea957cd63d
+      url: "https://pub.dev"
+    source: hosted
+    version: "6.4.0"
+  windows_file_picker:
+    dependency: transitive
+    description:
+      name: windows_file_picker
+      sha256: "225f58e64c15c2d7b34fb8faf3ca188831967f26b5a723d7c3a7969e41c9b5a5"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.1.0"
   xdg_directories:
     dependency: transitive
     description:
@@ -605,6 +765,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.1.0"
+  xml:
+    dependency: transitive
+    description:
+      name: xml
+      sha256: "67f0aff7be013d107995e9b75bf4e7f2c3ef2dfdb2c8e68024bba0a7fd5756a4"
+      url: "https://pub.dev"
+    source: hosted
+    version: "7.0.1"
   yaml:
     dependency: transitive
     description:

pubspec.yaml

@@ -16,6 +16,8 @@ dependencies:
   path: ^1.9.1
   path_provider: ^2.1.5
   sqflite: ^2.4.2
+  file_picker: ^12.1.2
+  share_plus: ^13.3.0
 
 dev_dependencies:
   flutter_test:

test/backup_format_test.dart

@@ -0,0 +1,78 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:receipity/services/backup_format.dart';
+
+void main() {
+  test('round-trips a backup document', () {
+    final original = const BackupDocument(
+      version: 1,
+      exportedAt: '2026-08-29T12:00:00.000',
+      darkMode: true,
+      supermarkets: [
+        {'id': 1, 'name': 'Jumbo', 'color': 0xFFEEC21B, 'sort_order': 0},
+      ],
+      products: [
+        {
+          'id': 1,
+          'name': 'Milk',
+          'normalized_name': 'MILK',
+          'last_price': 1.5,
+          'times_seen': 2,
+          'favourite': 1,
+          'image_path': 'products/product_1.jpg',
+          'supermarket': 'Jumbo',
+          'notes': 'Organic',
+          'created_at': '2026-08-29T12:00:00.000',
+          'updated_at': '2026-08-29T12:00:00.000',
+        },
+      ],
+      shops: [
+        {
+          'id': 8,
+          'supermarket': 'Jumbo',
+          'shopped_at': '2026-08-29T12:00:00.000',
+          'receipt_image_path': 'receipts/shop_8.jpg',
+          'total': 1.5,
+          'created_at': '2026-08-29T12:00:00.000',
+        },
+      ],
+      shopItems: [
+        {
+          'id': 1,
+          'shop_id': 8,
+          'product_id': 1,
+          'name': 'Milk',
+          'price': 1.5,
+          'quantity': 1,
+          'unit_price': 1.5,
+        },
+      ],
+      images: {'products/product_1.jpg': 'abc123'},
+    );
+
+    final parsed = BackupDocument.parse(original.encode());
+    expect(parsed.darkMode, isTrue);
+    expect(parsed.products.single['name'], 'Milk');
+    expect(parsed.shops.single['id'], 8);
+    expect(parsed.shopItems.single['product_id'], 1);
+    expect(parsed.images['products/product_1.jpg'], 'abc123');
+  });
+
+  test('rejects a file that is not a Receipity backup', () {
+    expect(
+      () => BackupDocument.parse('{"hello":"world"}'),
+      throwsFormatException,
+    );
+  });
+
+  test('maps stored photo paths to backup keys', () {
+    expect(
+      backupImageKey('/data/app_flutter/products/product_12.jpg'),
+      'products/product_12.jpg',
+    );
+    expect(
+      backupImageKey('/data/app_flutter/receipts/shop_3.jpg'),
+      'receipts/shop_3.jpg',
+    );
+    expect(backupImageKey(null), isNull);
+  });
+}

test/fuzzy_test.dart

@@ -0,0 +1,15 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:receipity/utils/fuzzy.dart';
+
+void main() {
+  test('matches substrings and character subsequences', () {
+    expect(fuzzyMatch('melk', 'JUMBO BIO VOLLE MELK'), isTrue);
+    expect(fuzzyMatch('jb melk', 'JUMBO BIO VOLLE MELK'), isTrue);
+    expect(fuzzyMatch('aard', 'AARDBEIEN'), isTrue);
+    expect(fuzzyMatch('xyz', 'AARDBEIEN'), isFalse);
+  });
+
+  test('ranks closer matches higher', () {
+    expect(fuzzyScore('melk', 'MELK')! > fuzzyScore('melk', 'JUMBO BIO VOLLE MELK')!, isTrue);
+  });
+}

test/supermarket_test.dart

@@ -0,0 +1,23 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:receipity/utils/supermarkets.dart';
+
+void main() {
+  test('detects Jumbo and Lidl from receipt text', () {
+    expect(detectSupermarket('Jumbo\nMelk 1,50'), 'Jumbo');
+    expect(
+      detectSupermarket('Dekamarkt\nMelk 1,50', names: ['Dekamarkt']),
+      'Dekamarkt',
+    );
+    expect(detectSupermarket('LIDL SUPERMARKT\nBananas 1.20'), 'Lidl');
+  });
+
+  test('detects Albert Heijn aliases', () {
+    expect(detectSupermarket('Albert Heijn\nKaas 2,00'), 'Albert Heijn');
+    expect(detectSupermarket('AH TO GO\nCoffee 1,80'), 'Albert Heijn');
+    expect(detectSupermarket('AH\nMilk 1.00'), 'Albert Heijn');
+  });
+
+  test('returns null when no supermarket is present', () {
+    expect(detectSupermarket('Milk 1.50\nBread 2.00'), isNull);
+  });
+}

test/widget_test.dart

@@ -6,7 +6,9 @@ import 'package:receipity/review_screen.dart';
 import 'package:receipity/services/product_repository.dart';
 
 void main() {
-  testWidgets('scan screen shows capture actions', (tester) async {
+  testWidgets('scan screen shows capture actions and bottom navigation', (
+    tester,
+  ) async {
     await tester.pumpWidget(ReceipityApp());
 
     expect(find.text('Receipity'), findsOneWidget);
@@ -17,6 +19,9 @@ void main() {
       find.textContaining('Take a photo of a shopping receipt'),
       findsOneWidget,
     );
+    expect(find.text('Products'), findsOneWidget);
+    expect(find.text('Scan'), findsOneWidget);
+    expect(find.text('Shop log'), findsOneWidget);
   });
 
   testWidgets('review screen lists items and can delete one', (tester) async {
@@ -28,7 +33,7 @@ void main() {
             LineItem(id: '2', name: 'Bread', price: 2),
           ],
           rawText: 'Milk 1.50\nBread 2.00',
-          repository: ProductRepository(),
+          repository: ProductRepository(databasePath: ':memory:'),
         ),
       ),
     );
@@ -36,11 +41,28 @@ void main() {
     expect(find.text('Milk'), findsOneWidget);
     expect(find.text('Bread'), findsOneWidget);
     expect(find.text('Add item'), findsOneWidget);
-    expect(find.text('Confirm'), findsOneWidget);
+    expect(find.textContaining('Save trip'), findsOneWidget);
+    expect(find.text('Supermarket'), findsOneWidget);
 
     await tester.drag(find.text('Milk'), const Offset(-500, 0));
     await tester.pumpAndSettle();
     expect(find.text('Milk'), findsNothing);
     expect(find.text('Bread'), findsOneWidget);
   });
+
+  testWidgets('review screen preselects a supermarket from OCR text', (
+    tester,
+  ) async {
+    await tester.pumpWidget(
+      MaterialApp(
+        home: ReviewScreen(
+          items: [LineItem(id: '1', name: 'Milk', price: 1.5)],
+          rawText: 'Jumbo\nMilk 1.50',
+          repository: ProductRepository(databasePath: ':memory:'),
+        ),
+      ),
+    );
+
+    expect(find.text('Jumbo'), findsWidgets);
+  });
 }