VCST-2612: Add validation for inactive payment methods (#19)

Author: OlegoO

src/VirtoCommerce.XOrder.Core/Validators/OrderErrorDescriber.cs

@@ -38,5 +38,10 @@ public static string PaymentMethodUnavailable(string code)
         {
             return $"The payment method code:{code} unavailable";
         }
+
+        public static string PaymentMethodInactive(string gatewayCode)
+        {
+            return $"Payment method {gatewayCode} is inactive";
+        }
     }
 }

src/VirtoCommerce.XOrder.Core/Validators/PaymentRequestValidator.cs

@@ -25,6 +25,11 @@ public PaymentRequestValidator()
                 .WithMessage(x => OrderErrorDescriber.PaymentMethodNotFound(x.Payment.GatewayCode))
                 .When(x => x.Payment != null);
 
+            RuleFor(x => x.Payment.PaymentMethod.IsActive)
+                .Equal(true)
+                .WithMessage(x => OrderErrorDescriber.PaymentMethodInactive(x.Payment.GatewayCode))
+                .When(x => x.Payment?.PaymentMethod != null);
+
             RuleFor(x => x.Store)
                 .NotNull()
                 .WithMessage(OrderErrorDescriber.StoreNotFound());