feat: add updateCategoryMine endpoint to manage product category updates

- Implemented a new PATCH endpoint in ProductsController to update the category of a user's product.
- Added corresponding service method in ProductsService to handle business logic and validation.
- Created UpdateCategoryMineDto for request validation.
- Enhanced error handling for forbidden actions and not found resources.
- Updated API error mapping in Flutter to handle specific forbidden messages.
- Modified ProductPickerField to allow product creation directly from the picker.
- Added tests for the new endpoint and service method to ensure proper functionality and error handling.

flutter/lib/core/api/api_error_mapper.dart

@@ -4,6 +4,11 @@ import 'package:flutter/services.dart';
 import '../l10n/l10n.dart';
 import 'api_exception.dart';
 
+const _safeForbiddenMessages = {
+  'Du kan inte omkategorisera, ta bort eller ändra produkter som är globala.',
+  'Du kan bara omkategorisera dina egna produkter',
+};
+
 String mapErrorToUserMessage(Object error, BuildContext context) {
   final l10n = context.l10n;
   if (error is ApiException) {
@@ -11,7 +16,9 @@ String mapErrorToUserMessage(Object error, BuildContext context) {
       case ApiErrorType.unauthorized:
         return l10n.sessionExpiredError;
       case ApiErrorType.forbidden:
-        return l10n.forbiddenError;
+        return _safeForbiddenMessages.contains(error.message)
+            ? error.message
+            : l10n.forbiddenError;
       case ApiErrorType.server:
         return l10n.serverError;
       case ApiErrorType.network:

flutter/lib/core/api/api_paths.dart

@@ -13,6 +13,7 @@ class ProductApiPaths {
   static const deleted = '/products/deleted';
   static const merge = '/products/merge';
   static const mergePrivate = '/products/private/merge';
+  static String updateMineCategory(int id) => '/products/mine/$id/category';
   static String mergePreview(int sourceProductId, int targetProductId) =>
       '/products/merge-preview?sourceProductId=$sourceProductId&targetProductId=$targetProductId';
   static String setStatus(int id) => '/products/$id/status';

flutter/lib/core/ui/product_picker_field.dart

@@ -36,6 +36,9 @@ class ProductPickerField extends StatelessWidget {
   /// If set, the picker bottom sheet opens with this text pre-filled in the search field.
   final String? initialQuery;
 
+  /// Optional callback to create a new product directly from the picker.
+  final Future<ProductOption?> Function(String name)? onCreate;
+
   const ProductPickerField({
     super.key,
     required this.products,
@@ -46,6 +49,7 @@ class ProductPickerField extends StatelessWidget {
     this.label = 'Produkt',
     this.errorText,
     this.initialQuery,
+    this.onCreate,
   });
 
   @override
@@ -57,7 +61,7 @@ class ProductPickerField extends StatelessWidget {
               orElse: () => null,
             );
 
-    final interactive = enabled && !isLoading && products.isNotEmpty;
+    final interactive = enabled && !isLoading && (products.isNotEmpty || onCreate != null);
 
     return MouseRegion(
       cursor: interactive ? SystemMouseCursors.click : MouseCursor.defer,
@@ -81,7 +85,9 @@ class ProductPickerField extends StatelessWidget {
               : selected == null
                   ? Text(
                       products.isEmpty
-                          ? 'Inga produkter tillgängliga'
+                          ? (onCreate != null
+                              ? 'Inga produkter tillgängliga. Tryck för att välja eller skapa.'
+                              : 'Inga produkter tillgängliga')
                           : 'Tryck för att välja produkt',
                     )
                   : Text(selected.name),
@@ -98,6 +104,7 @@ class ProductPickerField extends StatelessWidget {
       value: value,
       label: label,
       initialQuery: initialQuery,
+      onCreate: onCreate,
     );
     if (!context.mounted) return;
     if (result == null) return;

flutter/lib/features/inventory/presentation/create_inventory_screen.dart

@@ -18,6 +18,7 @@ import '../data/inventory_providers.dart';
 import '../../import/data/receipt_import_session.dart' show ImportDestination;
 import 'inventory_category_helpers.dart';
 import 'inventory_category_product_section.dart';
+import 'inventory_product_mutations.dart';
 
 class CreateInventoryScreen extends ConsumerStatefulWidget {
   final String? initialDestination;
@@ -185,18 +186,24 @@ class _CreateInventoryScreenState
     if (selected == null || !mounted) return;
     setState(() {
       _selectedCategoryId = selected.id;
-      final selectedCategoryIds = _selectedCategoryBranchIds();
-      final current = _selectedProduct();
-      final currentCategoryId = tryParseDynamicInt(current?['categoryId']);
-      if (!productInSelectedBranch(
-        productCategoryId: currentCategoryId,
-        selectedCategoryIds: selectedCategoryIds,
-      )) {
-        _selectedProductId = null;
-      }
     });
   }
 
+  Future<void> _syncSelectedProductCategory(String? token) async {
+    await syncSelectedProductCategory(
+      ref: ref,
+      token: token,
+      selectedProductId: _selectedProductId,
+      selectedCategoryId: _selectedCategoryId,
+      products: _products,
+      tryParseDynamicInt: tryParseDynamicInt,
+      setProducts: (updated) {
+        if (!mounted) return;
+        setState(() => _products = updated);
+      },
+    );
+  }
+
   Future<void> _pickDate(bool isBestBefore) async {
     final picked = await showDatePicker(
       context: context,
@@ -215,6 +222,21 @@ class _CreateInventoryScreenState
     }
   }
 
+  Future<ProductOption?> _createProductInSelectedCategory(String rawName) async {
+    return createProductInSelectedCategory(
+      ref: ref,
+      context: context,
+      rawName: rawName,
+      selectedCategoryId: _selectedCategoryId,
+      products: _products,
+      tryParseDynamicInt: tryParseDynamicInt,
+      setProducts: (updated) {
+        if (!mounted) return;
+        setState(() => _products = updated);
+      },
+    );
+  }
+
   Future<void> _save() async {
     if (_selectedProductId == null) {
       ScaffoldMessenger.of(context).showSnackBar(
@@ -253,6 +275,7 @@ class _CreateInventoryScreenState
     setState(() => _saving = true);
     try {
       final token = await ref.read(authStateProvider.future);
+      await _syncSelectedProductCategory(token);
       final body = <String, dynamic>{
         'productId': _selectedProductId,
         'quantity':
@@ -351,6 +374,7 @@ class _CreateInventoryScreenState
               productOptions: productOptions,
               selectedProductId: _selectedProductId,
               onProductChanged: (value) => setState(() => _selectedProductId = value),
+              onCreateProduct: _selectedCategoryId == null ? null : _createProductInSelectedCategory,
               isLoadingProducts: _loadingProducts,
               productEnabled: !_saving,
               productLabel: context.l10n.inventoryProductLabel,

flutter/lib/features/inventory/presentation/inventory_category_product_section.dart

@@ -17,6 +17,7 @@ class InventoryCategoryProductSection extends StatelessWidget {
   final List<product_picker.ProductOption> productOptions;
   final int? selectedProductId;
   final ValueChanged<int?> onProductChanged;
+  final Future<product_picker.ProductOption?> Function(String name)? onCreateProduct;
   final bool isLoadingProducts;
   final bool productEnabled;
   final String productLabel;
@@ -36,6 +37,7 @@ class InventoryCategoryProductSection extends StatelessWidget {
     required this.productOptions,
     required this.selectedProductId,
     required this.onProductChanged,
+    this.onCreateProduct,
     required this.isLoadingProducts,
     required this.productEnabled,
     required this.productLabel,
@@ -78,6 +80,7 @@ class InventoryCategoryProductSection extends StatelessWidget {
           enabled: productEnabled,
           label: productLabel,
           onChanged: onProductChanged,
+          onCreate: onCreateProduct,
         ),
       ],
     );

flutter/lib/features/inventory/presentation/inventory_edit_screen.dart

@@ -18,6 +18,7 @@ import '../data/inventory_providers.dart';
 import '../domain/inventory_item.dart';
 import 'inventory_category_helpers.dart';
 import 'inventory_category_product_section.dart';
+import 'inventory_product_mutations.dart';
 
 class InventoryEditScreen extends ConsumerStatefulWidget {
   final int itemId;
@@ -206,18 +207,24 @@ class _InventoryEditScreenState extends ConsumerState<InventoryEditScreen> {
     if (selected == null || !mounted) return;
     setState(() {
       _selectedCategoryId = selected.id;
-      final selectedCategoryIds = _selectedCategoryBranchIds();
-      final current = _selectedProduct();
-      final currentCategoryId = tryParseDynamicInt(current?['categoryId']);
-      if (!productInSelectedBranch(
-        productCategoryId: currentCategoryId,
-        selectedCategoryIds: selectedCategoryIds,
-      )) {
-        _selectedProductId = null;
-      }
     });
   }
 
+  Future<void> _syncSelectedProductCategory(String? token) async {
+    await syncSelectedProductCategory(
+      ref: ref,
+      token: token,
+      selectedProductId: _selectedProductId,
+      selectedCategoryId: _selectedCategoryId,
+      products: _products,
+      tryParseDynamicInt: tryParseDynamicInt,
+      setProducts: (updated) {
+        if (!mounted) return;
+        setState(() => _products = updated);
+      },
+    );
+  }
+
   Future<void> _pickDate(bool isBestBefore) async {
     final picked = await showDatePicker(
       context: context,
@@ -236,6 +243,21 @@ class _InventoryEditScreenState extends ConsumerState<InventoryEditScreen> {
     }
   }
 
+  Future<ProductOption?> _createProductInSelectedCategory(String rawName) async {
+    return createProductInSelectedCategory(
+      ref: ref,
+      context: context,
+      rawName: rawName,
+      selectedCategoryId: _selectedCategoryId,
+      products: _products,
+      tryParseDynamicInt: tryParseDynamicInt,
+      setProducts: (updated) {
+        if (!mounted) return;
+        setState(() => _products = updated);
+      },
+    );
+  }
+
   Future<void> _save() async {
     if (_selectedProductId == null) {
       ScaffoldMessenger.of(context).showSnackBar(
@@ -248,6 +270,7 @@ class _InventoryEditScreenState extends ConsumerState<InventoryEditScreen> {
     setState(() => _saving = true);
     try {
       final token = await ref.read(authStateProvider.future);
+      await _syncSelectedProductCategory(token);
       final body = <String, dynamic>{
         'productId': _selectedProductId,
         'quantity':
@@ -343,6 +366,7 @@ class _InventoryEditScreenState extends ConsumerState<InventoryEditScreen> {
                   productOptions: _productOptions(),
                   selectedProductId: _selectedProductId,
                   onProductChanged: (value) => setState(() => _selectedProductId = value),
+                  onCreateProduct: _selectedCategoryId == null ? null : _createProductInSelectedCategory,
                   isLoadingProducts: _loadingProducts,
                   productEnabled: !_saving,
                   productLabel: context.l10n.inventoryProductLabel,

flutter/lib/features/inventory/presentation/inventory_product_mutations.dart

@@ -0,0 +1,89 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+import '../../../core/api/api_error_mapper.dart';
+import '../../../core/api/api_paths.dart';
+import '../../../core/api/api_providers.dart';
+import '../../../core/ui/product_picker_field.dart' show ProductOption;
+import '../../auth/data/auth_providers.dart';
+
+Future<void> syncSelectedProductCategory({
+  required WidgetRef ref,
+  required String? token,
+  required int? selectedProductId,
+  required int? selectedCategoryId,
+  required List<Map<String, dynamic>> products,
+  required int? Function(dynamic) tryParseDynamicInt,
+  required void Function(List<Map<String, dynamic>>) setProducts,
+}) async {
+  final productId = selectedProductId;
+  final categoryId = selectedCategoryId;
+  if (productId == null || categoryId == null || token == null || token.isEmpty) return;
+
+  final current = products.cast<Map<String, dynamic>?>().firstWhere(
+        (p) => tryParseDynamicInt(p?['id']) == productId,
+        orElse: () => null,
+      );
+  final currentCategoryId = tryParseDynamicInt(current?['categoryId']);
+  if (currentCategoryId == categoryId) return;
+
+  final api = ref.read(apiClientProvider);
+  await api.patchJson(
+    ProductApiPaths.updateMineCategory(productId),
+    body: {'categoryId': categoryId},
+    token: token,
+  );
+
+  final updatedProducts = products
+      .map(
+        (p) => tryParseDynamicInt(p['id']) == productId
+            ? {...p, 'categoryId': categoryId}
+            : p,
+      )
+      .toList();
+  setProducts(updatedProducts);
+}
+
+Future<ProductOption?> createProductInSelectedCategory({
+  required WidgetRef ref,
+  required BuildContext context,
+  required String rawName,
+  required int? selectedCategoryId,
+  required List<Map<String, dynamic>> products,
+  required int? Function(dynamic) tryParseDynamicInt,
+  required void Function(List<Map<String, dynamic>>) setProducts,
+}) async {
+  final name = rawName.trim();
+  final categoryId = selectedCategoryId;
+  if (name.isEmpty || categoryId == null) return null;
+
+  try {
+    final token = await ref.read(authStateProvider.future);
+    final api = ref.read(apiClientProvider);
+    final data = await api.postJson(
+      ProductApiPaths.createPrivate,
+      body: {
+        'name': name,
+        'categoryId': categoryId,
+      },
+      token: token,
+    );
+
+    final created = Map<String, dynamic>.from(data as Map);
+    final createdId = tryParseDynamicInt(created['id']);
+    if (createdId == null) return null;
+
+    setProducts([...products, created]);
+
+    return (
+      id: createdId,
+      name: (created['canonicalName'] ?? created['name'] ?? '').toString(),
+      categoryId: tryParseDynamicInt(created['categoryId']),
+    );
+  } catch (e) {
+    ScaffoldMessenger.of(context).showSnackBar(
+      buildCopyableErrorSnackBar(context, mapErrorToUserMessage(e, context)),
+    );
+    return null;
+  }
+}