Mobile App Development

// cart_provider.dart (Riverpod)
class CartNotifier extends StateNotifier<List<CartItem>> {
  CartNotifier() : super([]);

  void addItem(Product product) {
    final existingIndex = state.indexWhere((item) => item.product.id == product.id);
    if (existingIndex != -1) {
      state = [
        for (var i = 0; i < state.length; i++)
          if (i == existingIndex)
            state[i].copyWith(quantity: state[i].quantity + 1)
          else
            state[i]
      ];
    } else {
      state = [...state, CartItem(product: product, quantity: 1)];
    }
  }

  void removeItem(int id) {
    state = state.where((item) => item.product.id != id).toList();
  }
}

final cartProvider = StateNotifierProvider<CartNotifier, List<CartItem>>((ref) {
  return CartNotifier();
});