feat: add edit category page

- Implemented edit category UI
- Added bloc logic
- Integrated with repository

Author: fulleni

lib/content_management/view/edit_category_page.dart

@@ -0,0 +1,201 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:go_router/go_router.dart';
+import 'package:ht_dashboard/content_management/bloc/content_management_bloc.dart';
+import 'package:ht_dashboard/content_management/bloc/edit_category/edit_category_bloc.dart';
+import 'package:ht_dashboard/l10n/l10n.dart';
+import 'package:ht_dashboard/shared/shared.dart';
+import 'package:ht_data_repository/ht_data_repository.dart';
+import 'package:ht_shared/ht_shared.dart';
+
+/// {@template edit_category_page}
+/// A page for editing an existing category.
+/// It uses a [BlocProvider] to create and provide an [EditCategoryBloc].
+/// {@endtemplate}
+class EditCategoryPage extends StatelessWidget {
+  /// {@macro edit_category_page}
+  const EditCategoryPage({required this.categoryId, super.key});
+
+  /// The ID of the category to be edited.
+  final String categoryId;
+
+  @override
+  Widget build(BuildContext context) {
+    return BlocProvider(
+      create: (context) => EditCategoryBloc(
+        categoriesRepository: context.read<HtDataRepository<Category>>(),
+        categoryId: categoryId,
+      )..add(const EditCategoryLoaded()),
+      child: const _EditCategoryView(),
+    );
+  }
+}
+
+class _EditCategoryView extends StatefulWidget {
+  const _EditCategoryView();
+
+  @override
+  State<_EditCategoryView> createState() => _EditCategoryViewState();
+}
+
+class _EditCategoryViewState extends State<_EditCategoryView> {
+  final _formKey = GlobalKey<FormState>();
+  late final TextEditingController _nameController;
+  late final TextEditingController _descriptionController;
+  late final TextEditingController _iconUrlController;
+
+  @override
+  void initState() {
+    super.initState();
+    final state = context.read<EditCategoryBloc>().state;
+    _nameController = TextEditingController(text: state.name);
+    _descriptionController = TextEditingController(text: state.description);
+    _iconUrlController = TextEditingController(text: state.iconUrl);
+  }
+
+  @override
+  void dispose() {
+    _nameController.dispose();
+    _descriptionController.dispose();
+    _iconUrlController.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final l10n = context.l10n;
+    return Scaffold(
+      appBar: AppBar(
+        title: Text(l10n.editCategory),
+        actions: [
+          BlocBuilder<EditCategoryBloc, EditCategoryState>(
+            builder: (context, state) {
+              if (state.status == EditCategoryStatus.submitting) {
+                return const Padding(
+                  padding: EdgeInsets.only(right: AppSpacing.lg),
+                  child: SizedBox(
+                    width: 24,
+                    height: 24,
+                    child: CircularProgressIndicator(strokeWidth: 3),
+                  ),
+                );
+              }
+              return IconButton(
+                icon: const Icon(Icons.save),
+                tooltip: l10n.saveChanges,
+                onPressed: state.isFormValid
+                    ? () => context.read<EditCategoryBloc>().add(
+                        const EditCategorySubmitted(),
+                      )
+                    : null,
+              );
+            },
+          ),
+        ],
+      ),
+      body: BlocConsumer<EditCategoryBloc, EditCategoryState>(
+        listenWhen: (previous, current) =>
+            previous.status != current.status ||
+            previous.initialCategory != current.initialCategory,
+        listener: (context, state) {
+          if (state.status == EditCategoryStatus.success &&
+              state.initialCategory != null &&
+              ModalRoute.of(context)!.isCurrent) {
+            ScaffoldMessenger.of(context)
+              ..hideCurrentSnackBar()
+              ..showSnackBar(
+                // TODO(l10n): Localize this message.
+                const SnackBar(content: Text('Category updated successfully.')),
+              );
+            context.read<ContentManagementBloc>().add(
+              const LoadCategoriesRequested(),
+            );
+            context.pop();
+          }
+          if (state.status == EditCategoryStatus.failure) {
+            ScaffoldMessenger.of(context)
+              ..hideCurrentSnackBar()
+              ..showSnackBar(
+                SnackBar(
+                  content: Text(state.errorMessage ?? l10n.unknownError),
+                  backgroundColor: Theme.of(context).colorScheme.error,
+                ),
+              );
+          }
+          if (state.initialCategory != null) {
+            _nameController.text = state.name;
+            _descriptionController.text = state.description;
+            _iconUrlController.text = state.iconUrl;
+          }
+        },
+        builder: (context, state) {
+          if (state.status == EditCategoryStatus.loading) {
+            return LoadingStateWidget(
+              icon: Icons.category,
+              // TODO(l10n): Localize this message.
+              headline: 'Loading Category...',
+              subheadline: l10n.pleaseWait,
+            );
+          }
+
+          if (state.status == EditCategoryStatus.failure &&
+              state.initialCategory == null) {
+            return FailureStateWidget(
+              message: state.errorMessage ?? l10n.unknownError,
+              onRetry: () => context.read<EditCategoryBloc>().add(
+                const EditCategoryLoaded(),
+              ),
+            );
+          }
+
+          return SingleChildScrollView(
+            child: Padding(
+              padding: const EdgeInsets.all(AppSpacing.lg),
+              child: Form(
+                key: _formKey,
+                child: Column(
+                  crossAxisAlignment: CrossAxisAlignment.start,
+                  children: [
+                    TextFormField(
+                      controller: _nameController,
+                      decoration: InputDecoration(
+                        labelText: l10n.categoryName,
+                        border: const OutlineInputBorder(),
+                      ),
+                      onChanged: (value) => context
+                          .read<EditCategoryBloc>()
+                          .add(EditCategoryNameChanged(value)),
+                    ),
+                    const SizedBox(height: AppSpacing.lg),
+                    TextFormField(
+                      controller: _descriptionController,
+                      decoration: InputDecoration(
+                        labelText: l10n.description,
+                        border: const OutlineInputBorder(),
+                      ),
+                      maxLines: 3,
+                      onChanged: (value) => context
+                          .read<EditCategoryBloc>()
+                          .add(EditCategoryDescriptionChanged(value)),
+                    ),
+                    const SizedBox(height: AppSpacing.lg),
+                    TextFormField(
+                      controller: _iconUrlController,
+                      decoration: InputDecoration(
+                        labelText: l10n.iconUrl,
+                        border: const OutlineInputBorder(),
+                      ),
+                      onChanged: (value) => context
+                          .read<EditCategoryBloc>()
+                          .add(EditCategoryIconUrlChanged(value)),
+                    ),
+                  ],
+                ),
+              ),
+            ),
+          );
+        },
+      ),
+    );
+  }
+}