uh oh, blommekes uses CQRS from now on #OverArchitecture /cc @yreynhout ;)

transaction.cs

using MinimalisticCQRS.Infrastructure;

namespace Blommekes.Domain.Entities
{
    public class Order : AR
    {
        private bool OrderClosed;

        enum OrderStatus
        {
            None,
            ProductAddedToOrder,
            PaymentRequested,
            PaymentAccepted,
            PaymentCanceled,
            PaymentTimedOut,
        }

        private string ProductId = null;
        private OrderStatus Status= OrderStatus.None;
        private  string PaymentId;
        private decimal TotalPrice;


        public void RegisterOrder()
        {
            Guard.Against(this.Status >= OrderStatus.PaymentRequested, "A payment has already been launched for this order");
            Apply.OrderRegistered(OrderId: this.Id);
        }

        public void AddProduct(string ProductId)
        {
            Guard.Against(this.Status >= OrderStatus.PaymentRequested, "A payment has already been launched for this order");
            Apply.ProductAddedToOrder(ProductId, OrderId: this.Id);
        }

        public void RequestPayment(string PaymentId,decimal TotalPrice)
        {
            Guard.Against(this.Status < OrderStatus.ProductAddedToOrder, "This order does not yet contain any products");
            Guard.Against(this.Status >= OrderStatus.PaymentRequested, "A payment has already been launched for this order");
            Apply.PaymentRequested(PaymentId, TotalPrice, OrderId: this.Id);
        }

        public void AcceptPayment(string PaymentId,string ProductId,decimal TotalPrice)
        {
            Guard.Against(this.Status != OrderStatus.PaymentRequested, "This order is currently not in the payment request status");
            Guard.Against(this.PaymentId != PaymentId,"There is a mismatch between the payment id request and response");
            Guard.Against(this.ProductId != ProductId,"There is a mismatch between the products for the request and response");
            Guard.Against(this.TotalPrice != TotalPrice,"There is a mismatch between the price for the request and response");
            Apply.PaymentAccepted(OrderId: this.Id);
        }

        public void CancelPayment(string PaymentId, string ProductId, decimal TotalPrice)
        {
            Guard.Against(this.Status != OrderStatus.PaymentRequested, "This order is currently not in the payment request status");
            Guard.Against(this.PaymentId != PaymentId, "There is a mismatch between the payment id request and response");
            Guard.Against(this.ProductId != ProductId, "There is a mismatch between the products for the request and response");
            Guard.Against(this.TotalPrice != TotalPrice, "There is a mismatch between the price for the request and response");
            Apply.PaymentCanceled(OrderId: this.Id);
        }

        public void ReportPaymentTimeout(string PaymentId)
        {
            Guard.Against(this.Status != OrderStatus.PaymentRequested, "This order is currently not in the payment request status");
            Guard.Against(this.PaymentId != PaymentId, "There is a mismatch between the payment id request and response");
            Apply.PaymentTimedOut(PaymentId,OrderId: this.Id);
        }

        void OnOrderRegistered()
        {
            this.Status = OrderStatus.None;
        }

        void OnProductAddedToOrder(string ProductId)
        {
            this.ProductId = ProductId;
        }

        void OnPaymentRequested(string PaymentId,decimal TotalPrice)
        {
            this.Status = OrderStatus.PaymentRequested;
            this.PaymentId = PaymentId;
            this.TotalPrice = TotalPrice;
        }

        void OnPaymentAccepted()
        {
            this.Status = OrderStatus.PaymentAccepted;
        }

        void OnPaymentCanceled()
        {
            this.Status = OrderStatus.PaymentCanceled;
        }
    }
}

Removed it again #overarchitecture