public async Task AddItemAsync()

in src/cartservice/src/cartstore/RedisCartStore.cs [33:66]
33 lines of code
4 McCabe index (conditional complexity)

        public async Task AddItemAsync(string userId, string productId, int quantity)
        {
            Console.WriteLine($"AddItemAsync called with userId={userId}, productId={productId}, quantity={quantity}");

            try
            {
                Hipstershop.Cart cart;
                var value = await _cache.GetAsync(userId);
                if (value == null)
                {
                    cart = new Hipstershop.Cart();
                    cart.UserId = userId;
                    cart.Items.Add(new Hipstershop.CartItem { ProductId = productId, Quantity = quantity });
                }
                else
                {
                    cart = Hipstershop.Cart.Parser.ParseFrom(value);
                    var existingItem = cart.Items.SingleOrDefault(i => i.ProductId == productId);
                    if (existingItem == null)
                    {
                        cart.Items.Add(new Hipstershop.CartItem { ProductId = productId, Quantity = quantity });
                    }
                    else
                    {
                        existingItem.Quantity += quantity;
                    }
                }
                await _cache.SetAsync(userId, cart.ToByteArray());
            }
            catch (Exception ex)
            {
                throw new RpcException(new Status(StatusCode.FailedPrecondition, $"Can't access cart storage. {ex}"));
            }
        }