Initialer Commit: Projekt Start

lib/providers/cart_provider.dart

@@ -0,0 +1,118 @@
+import 'package:flutter/foundation.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+import 'dart:convert';
+import '../models/product.dart';
+
+class CartItem {
+  final Product product;
+  int quantity;
+
+  CartItem({
+    required this.product,
+    this.quantity = 1,
+  });
+
+  double get totalPrice => product.priceValue * quantity;
+
+  Map<String, dynamic> toJson() {
+    return {
+      'product_id': product.id,
+      'quantity': quantity,
+      'product': product.toJson(),
+    };
+  }
+
+  factory CartItem.fromJson(Map<String, dynamic> json) {
+    return CartItem(
+      product: Product.fromJson(json['product']),
+      quantity: json['quantity'] ?? 1,
+    );
+  }
+}
+
+class CartProvider extends ChangeNotifier {
+  final List<CartItem> _items = [];
+  static const String _cartKey = 'cart_items';
+
+  List<CartItem> get items => _items;
+
+  int get itemCount => _items.fold(0, (sum, item) => sum + item.quantity);
+
+  double get totalPrice {
+    return _items.fold(0.0, (sum, item) => sum + item.totalPrice);
+  }
+
+  CartProvider() {
+    _loadCart();
+  }
+
+  /// Lädt gespeicherten Warenkorb
+  Future<void> _loadCart() async {
+    try {
+      final prefs = await SharedPreferences.getInstance();
+      final cartJson = prefs.getString(_cartKey);
+      
+      if (cartJson != null) {
+        final List<dynamic> cartData = json.decode(cartJson);
+        _items.clear();
+        _items.addAll(
+          cartData.map((item) => CartItem.fromJson(item)).toList(),
+        );
+        notifyListeners();
+      }
+    } catch (e) {
+      print('Fehler beim Laden des Warenkorbs: $e');
+    }
+  }
+
+  /// Speichert Warenkorb
+  Future<void> _saveCart() async {
+    try {
+      final prefs = await SharedPreferences.getInstance();
+      final cartJson = json.encode(
+        _items.map((item) => item.toJson()).toList(),
+      );
+      await prefs.setString(_cartKey, cartJson);
+    } catch (e) {
+      print('Fehler beim Speichern des Warenkorbs: $e');
+    }
+  }
+
+  void addItem(Product product) {
+    final existingIndex = _items.indexWhere((item) => item.product.id == product.id);
+    
+    if (existingIndex >= 0) {
+      _items[existingIndex].quantity++;
+    } else {
+      _items.add(CartItem(product: product));
+    }
+    notifyListeners();
+    _saveCart();
+  }
+
+  void removeItem(Product product) {
+    final existingIndex = _items.indexWhere((item) => item.product.id == product.id);
+    
+    if (existingIndex >= 0) {
+      if (_items[existingIndex].quantity > 1) {
+        _items[existingIndex].quantity--;
+      } else {
+        _items.removeAt(existingIndex);
+      }
+      notifyListeners();
+      _saveCart();
+    }
+  }
+
+  void removeItemCompletely(Product product) {
+    _items.removeWhere((item) => item.product.id == product.id);
+    notifyListeners();
+    _saveCart();
+  }
+
+  void clearCart() {
+    _items.clear();
+    notifyListeners();
+    _saveCart();
+  }
+}