feat: implement API client with JSON handling and error mapping; enhance routing and state management in app shell

flutter/lib/features/auth/data/auth_repository.dart

@@ -1,5 +1,5 @@
-import 'dart:convert';
 import '../../../core/api/api_client.dart';
+import '../../../core/api/api_exception.dart';
 import '../../../core/platform/token_storage.dart';
 
 class AuthRepository {
@@ -9,17 +9,37 @@ class AuthRepository {
   AuthRepository(this._api, this._storage);
 
   Future<String> login(String username, String password) async {
-    final response = await _api.post(
-      '/auth/login',
-      jsonEncode({'username': username, 'password': password}),
-    );
-    if (response.statusCode != 200 && response.statusCode != 201) {
-      throw Exception('Login failed: ${response.statusCode}');
+    try {
+      final data = await _api.postJson(
+        '/auth/login',
+        body: {'username': username, 'password': password},
+      );
+
+      if (data is! Map<String, dynamic>) {
+        throw const ApiException(
+          type: ApiErrorType.unknown,
+          message: 'Ogiltigt svar fran servern.',
+        );
+      }
+
+      final token = data['accessToken'];
+      if (token is! String || token.isEmpty) {
+        throw const ApiException(
+          type: ApiErrorType.unknown,
+          message: 'Svar saknar access token.',
+        );
+      }
+
+      await _storage.saveToken(token);
+      return token;
+    } on ApiException {
+      rethrow;
+    } catch (_) {
+      throw const ApiException(
+        type: ApiErrorType.network,
+        message: 'Kunde inte na servern.',
+      );
     }
-    final data = jsonDecode(response.body) as Map<String, dynamic>;
-    final token = data['accessToken'] as String;
-    await _storage.saveToken(token);
-    return token;
   }
 
   Future<void> logout() => _storage.deleteToken();

flutter/lib/features/auth/presentation/login_screen.dart

@@ -1,6 +1,8 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
+
+import '../../../core/api/api_error_mapper.dart';
 import '../data/auth_providers.dart';
 
 class LoginScreen extends ConsumerStatefulWidget {
@@ -72,7 +74,8 @@ class _LoginScreenState extends ConsumerState<LoginScreen> {
               Padding(
                 padding: const EdgeInsets.only(top: 12),
                 child: Text(
-                  'Inloggning misslyckades',
+                  mapErrorToUserMessage(authState.error!),
+                  textAlign: TextAlign.center,
                   style: TextStyle(color: Theme.of(context).colorScheme.error),
                 ),
               ),

flutter/lib/features/profile/presentation/profile_screen.dart

@@ -1,37 +1,12 @@
 import 'package:flutter/material.dart';
-import 'package:flutter_riverpod/flutter_riverpod.dart';
-import 'package:go_router/go_router.dart';
-import '../../auth/data/auth_providers.dart';
 
-class ProfileScreen extends ConsumerWidget {
+class ProfileScreen extends StatelessWidget {
   const ProfileScreen({super.key});
 
-  Future<void> _logout(BuildContext context, WidgetRef ref) async {
-    await ref.read(authStateProvider.notifier).logout();
-    if (context.mounted) context.go('/login');
-  }
-
   @override
-  Widget build(BuildContext context, WidgetRef ref) {
-    return Scaffold(
-      appBar: AppBar(
-        title: const Text('Profil'),
-        actions: [
-          IconButton(
-            tooltip: 'Recept',
-            icon: const Icon(Icons.restaurant_menu),
-            onPressed: () => context.go('/recipes'),
-          ),
-          IconButton(
-            tooltip: 'Logga ut',
-            icon: const Icon(Icons.logout),
-            onPressed: () => _logout(context, ref),
-          ),
-        ],
-      ),
-      body: const Center(
-        child: Text('Profilsida (grundversion)'),
-      ),
+  Widget build(BuildContext context) {
+    return const Center(
+      child: Text('Profilsida (grundversion)'),
     );
   }
 }

flutter/lib/features/recipes/data/recipe_repository.dart

@@ -1,5 +1,5 @@
-import 'dart:convert';
 import '../../../core/api/api_client.dart';
+import '../../../core/api/api_exception.dart';
 import '../domain/recipe.dart';
 
 class RecipeRepository {
@@ -8,13 +8,26 @@ class RecipeRepository {
   RecipeRepository(this._api);
 
   Future<List<Recipe>> fetchRecipes({String? token}) async {
-    final response = await _api.get('/recipes', token: token);
-    if (response.statusCode != 200) {
-      throw Exception('Failed to load recipes: ${response.statusCode}');
+    try {
+      final data = await _api.getJson('/recipes', token: token);
+
+      if (data is! List) {
+        throw const ApiException(
+          type: ApiErrorType.unknown,
+          message: 'Ogiltigt svar fran servern.',
+        );
+      }
+
+      return data
+          .map((e) => Recipe.fromJson(e as Map<String, dynamic>))
+          .toList();
+    } on ApiException {
+      rethrow;
+    } catch (_) {
+      throw const ApiException(
+        type: ApiErrorType.network,
+        message: 'Kunde inte hamta recept.',
+      );
     }
-    final List<dynamic> data = jsonDecode(response.body) as List<dynamic>;
-    return data
-        .map((e) => Recipe.fromJson(e as Map<String, dynamic>))
-        .toList();
   }
 }

flutter/lib/features/recipes/presentation/recipes_screen.dart

@@ -1,40 +1,31 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
-import 'package:go_router/go_router.dart';
-import '../../auth/data/auth_providers.dart';
+
+import '../../../core/api/api_error_mapper.dart';
+import '../../../core/ui/async_state_views.dart';
 import '../data/recipe_providers.dart';
 
 class RecipesScreen extends ConsumerWidget {
   const RecipesScreen({super.key});
 
-  Future<void> _logout(BuildContext context, WidgetRef ref) async {
-    await ref.read(authStateProvider.notifier).logout();
-    if (context.mounted) context.go('/login');
-  }
-
   @override
   Widget build(BuildContext context, WidgetRef ref) {
     final recipesAsync = ref.watch(recipesProvider);
-    return Scaffold(
-      appBar: AppBar(
-        title: const Text('Recept'),
-        actions: [
-          IconButton(
-            tooltip: 'Profil',
-            icon: const Icon(Icons.person),
-            onPressed: () => context.go('/profile'),
-          ),
-          IconButton(
-            tooltip: 'Logga ut',
-            icon: const Icon(Icons.logout),
-            onPressed: () => _logout(context, ref),
-          ),
-        ],
+    return recipesAsync.when(
+      loading: () => const LoadingStateView(label: 'Laddar recept...'),
+      error: (error, _) => ErrorStateView(
+        message: mapErrorToUserMessage(error),
+        onRetry: () => ref.invalidate(recipesProvider),
       ),
-      body: recipesAsync.when(
-        loading: () => const Center(child: CircularProgressIndicator()),
-        error: (e, _) => Center(child: Text('Fel: $e')),
-        data: (recipes) => ListView.builder(
+      data: (recipes) {
+        if (recipes.isEmpty) {
+          return const EmptyStateView(
+            title: 'Inga recept hittades',
+            description: 'Lagg till ett recept for att komma igang.',
+          );
+        }
+
+        return ListView.builder(
           itemCount: recipes.length,
           itemBuilder: (context, index) {
             final recipe = recipes[index];
@@ -52,8 +43,8 @@ class RecipesScreen extends ConsumerWidget {
                   : null,
             );
           },
-        ),
-      ),
+        );
+      },
     );
   }
 }