public bool BuyProduct(PurchaseDetails purchase)
        {
            var products  = _productRepo.GetAllProducts().ToList();
            var customers = _customerRepo.GetAllCustomers().ToList();

            if (!_purchaseservice.IsProductExists(products, purchase))
            {
                return(false);
                // return "Selected Product not existed";
            }
            else if (!_purchaseservice.IsCustomerExists(customers, purchase))
            {
                return(false);
                // return "Selected CUstomer not existed";
            }
            else if (!_purchaseservice.IsProductQuantityAvilable(products, purchase))
            {
                return(false);
                // return "Selected producted already sold out";
            }
            _purchaseservice.CalculatePrice(customers, products, purchase);
            _purchaseRepo.Addpurchase(purchase);
            var product = products.Find(p => p.Id == purchase.ProductId);

            product.Quantity = product.Quantity - purchase.Quantity;
            _productRepo.Update(product);
            return(true);
        }