feat: Implement admin pantry item management with create and update functionality, including category selection and validation

flutter/lib/features/admin/presentation/admin_inventory_panel.dart

@@ -3,7 +3,10 @@ import 'package:flutter/services.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 
 import '../../../core/api/api_error_mapper.dart';
+import '../../../core/ui/category_then_product_picker.dart';
+import '../../../core/ui/product_picker_field.dart';
 import '../data/admin_repository.dart';
+import '../domain/admin_category_node.dart';
 import '../domain/admin_inventory_item.dart';
 import '../domain/admin_product.dart';
 import '../domain/user_admin.dart';
@@ -34,6 +37,7 @@ class _AdminInventoryPanelState extends ConsumerState<AdminInventoryPanel> {
   _InventorySort _sort = _InventorySort.newest;
   List<AdminInventoryItem> _items = [];
   List<AdminProduct> _products = [];
+  List<AdminCategoryNode> _categories = [];
   List<UserAdmin> _users = [];
 
   @override
@@ -55,13 +59,15 @@ class _AdminInventoryPanelState extends ConsumerState<AdminInventoryPanel> {
               sort: _sortParam,
             ),
         ref.read(adminRepositoryProvider).listGlobalProducts(),
+        ref.read(adminRepositoryProvider).listCategoryTree(),
         ref.read(adminRepositoryProvider).listUsers(),
       ]);
       if (!mounted) return;
       setState(() {
         _items = results[0] as List<AdminInventoryItem>;
         _products = results[1] as List<AdminProduct>;
-        _users = results[2] as List<UserAdmin>;
+        _categories = results[2] as List<AdminCategoryNode>;
+        _users = results[3] as List<UserAdmin>;
       });
     } catch (e) {
       if (!mounted) return;
@@ -94,7 +100,8 @@ class _AdminInventoryPanelState extends ConsumerState<AdminInventoryPanel> {
       return item.displayName.toLowerCase().contains(q) ||
           item.username.toLowerCase().contains(q) ||
           item.userEmail.toLowerCase().contains(q) ||
-          (item.location ?? '').toLowerCase().contains(q);
+          (item.location ?? '').toLowerCase().contains(q) ||
+          (item.categoryPath ?? '').toLowerCase().contains(q);
     }).toList();
   }
 
@@ -453,6 +460,7 @@ class _AdminInventoryPanelState extends ConsumerState<AdminInventoryPanel> {
       builder: (context) => _InventoryFormDialog(
         users: _users,
         products: _products,
+        categories: _categories,
         initial: initial,
         initialOwnerUserId: initialOwnerUserId,
       ),
@@ -656,7 +664,8 @@ class _AdminInventoryPanelState extends ConsumerState<AdminInventoryPanel> {
                         title: Text(item.displayName),
                         subtitle: Text(
                           '${item.quantity} ${item.unit} · ${item.username} (${item.userEmail})'
-                          '${item.location == null || item.location!.isEmpty ? '' : ' · ${item.location}'}',
+                          '${item.location == null || item.location!.isEmpty ? '' : ' · ${item.location}'}'
+                          '${item.categoryPath == null || item.categoryPath!.isEmpty ? '' : ' · ${item.categoryPath}'}',
                         ),
                         trailing: Row(
                           mainAxisSize: MainAxisSize.min,
@@ -730,12 +739,14 @@ class _InventoryFormValues {
 class _InventoryFormDialog extends StatefulWidget {
   final List<UserAdmin> users;
   final List<AdminProduct> products;
+  final List<AdminCategoryNode> categories;
   final AdminInventoryItem? initial;
   final int? initialOwnerUserId;
 
   const _InventoryFormDialog({
     required this.users,
     required this.products,
+    required this.categories,
     this.initial,
     this.initialOwnerUserId,
   });
@@ -756,6 +767,9 @@ class _InventoryFormDialogState extends State<_InventoryFormDialog> {
 
   int? _ownerUserId;
   int? _productId;
+  int? _categoryId;
+  String? _categoryPath;
+  String? _productErrorText;
 
   @override
   void initState() {
@@ -763,6 +777,9 @@ class _InventoryFormDialogState extends State<_InventoryFormDialog> {
     final initial = widget.initial;
     _ownerUserId = initial?.userId ?? widget.initialOwnerUserId;
     _productId = initial?.productId;
+    final initialProduct = _productById(_productId);
+    _categoryId = initialProduct?.categoryId;
+    _categoryPath = initialProduct?.categoryPath;
     _quantityController = TextEditingController(
       text: initial == null ? '' : initial.quantity.toString(),
     );
@@ -786,6 +803,44 @@ class _InventoryFormDialogState extends State<_InventoryFormDialog> {
     super.dispose();
   }
 
+  AdminProduct? _productById(int? id) {
+    if (id == null) return null;
+    for (final product in widget.products) {
+      if (product.id == id) return product;
+    }
+    return null;
+  }
+
+  List<ProductOption> _productOptions() {
+    final source = _categoryId == null
+        ? widget.products
+        : widget.products.where((p) => p.categoryId == _categoryId).toList();
+    final sorted = [...source]
+      ..sort((a, b) => a.displayName.toLowerCase().compareTo(b.displayName.toLowerCase()));
+    return sorted
+        .map((p) => (id: p.id, name: p.displayName, categoryId: p.categoryId))
+        .toList();
+  }
+
+  Future<void> _pickCategory() async {
+    final selected = await CategoryThenProductPicker.showCategorySheet(
+      context,
+      categoryTree: widget.categories,
+      preselectedCategoryId: _categoryId,
+    );
+    if (selected == null || !mounted) return;
+    setState(() {
+      _categoryId = selected.id;
+      _categoryPath = selected.path;
+      if (_productId != null) {
+        final current = _productById(_productId);
+        if (current?.categoryId != _categoryId) {
+          _productId = null;
+        }
+      }
+    });
+  }
+
   @override
   Widget build(BuildContext context) {
     return AlertDialog(
@@ -833,20 +888,53 @@ class _InventoryFormDialogState extends State<_InventoryFormDialog> {
                   ),
                   const SizedBox(height: 12),
                 ],
-                DropdownButtonFormField<int>(
-                  initialValue: _productId,
-                  items: widget.products
-                      .map((p) => DropdownMenuItem<int>(
-                            value: p.id,
-                            child: Text(
-                              p.displayName,
-                              overflow: TextOverflow.ellipsis,
-                            ),
-                          ))
-                      .toList(),
-                  onChanged: (value) => setState(() => _productId = value),
-                  decoration: const InputDecoration(labelText: 'Produkt'),
-                  validator: (value) => value == null ? 'Välj en produkt' : null,
+                GestureDetector(
+                  onTap: _pickCategory,
+                  child: InputDecorator(
+                    decoration: const InputDecoration(
+                      labelText: 'Kategori',
+                      border: OutlineInputBorder(),
+                    ),
+                    child: Text(
+                      _categoryPath == null || _categoryPath!.trim().isEmpty
+                          ? 'Tryck för att välja kategori'
+                          : _categoryPath!,
+                    ),
+                  ),
+                ),
+                const SizedBox(height: 12),
+                Row(
+                  children: [
+                    OutlinedButton.icon(
+                      onPressed: _pickCategory,
+                      icon: const Icon(Icons.category_outlined),
+                      label: const Text('Välj kategori'),
+                    ),
+                    const SizedBox(width: 8),
+                    OutlinedButton.icon(
+                      onPressed: () {
+                        setState(() {
+                          _categoryId = null;
+                          _categoryPath = null;
+                        });
+                      },
+                      icon: const Icon(Icons.clear),
+                      label: const Text('Rensa kategori'),
+                    ),
+                  ],
+                ),
+                const SizedBox(height: 12),
+                ProductPickerField(
+                  products: _productOptions(),
+                  value: _productId,
+                  label: 'Produkt',
+                  errorText: _productErrorText,
+                  onChanged: (value) {
+                    setState(() {
+                      _productId = value;
+                      _productErrorText = null;
+                    });
+                  },
                 ),
                 const SizedBox(height: 12),
                 TextFormField(
@@ -905,6 +993,10 @@ class _InventoryFormDialogState extends State<_InventoryFormDialog> {
         FilledButton(
           onPressed: () {
             if (!_formKey.currentState!.validate()) return;
+            if (_productId == null) {
+              setState(() => _productErrorText = 'Välj en produkt');
+              return;
+            }
 
             final quantity =
                 double.parse(_quantityController.text.trim().replaceAll(',', '.'));