From b3584b5e5ba2c2a7ed794135b2dee5dd817a0fcb Mon Sep 17 00:00:00 2001
From: StuartFerguson <stuart_ferguson1development@outlook.com>
Date: Thu, 28 Aug 2025 17:50:38 +0100
Subject: [PATCH] add retry to MerchantFeeSettledEvent

---
 ...erchantStatementDomainEventHandlerTests.cs | 32 ++++++++++++++
 .../MerchantStatementDomainEventHandler.cs    | 43 ++++++++++++++-----
 2 files changed, 64 insertions(+), 11 deletions(-)

diff --git a/TransactionProcessor.BusinessLogic.Tests/DomainEventHandlers/MerchantStatementDomainEventHandlerTests.cs b/TransactionProcessor.BusinessLogic.Tests/DomainEventHandlers/MerchantStatementDomainEventHandlerTests.cs
index 572e351f..198f8a2f 100644
--- a/TransactionProcessor.BusinessLogic.Tests/DomainEventHandlers/MerchantStatementDomainEventHandlerTests.cs
+++ b/TransactionProcessor.BusinessLogic.Tests/DomainEventHandlers/MerchantStatementDomainEventHandlerTests.cs
@@ -22,6 +22,7 @@ public class MerchantStatementDomainEventHandlerTests : DomainEventHandlerTests
     public MerchantStatementDomainEventHandlerTests(ITestOutputHelper testOutputHelper) : base(testOutputHelper)
     {
         this.EventHandler = new MerchantStatementDomainEventHandler(this.Mediator.Object);
+        Logger.Initialise(new NullLogger());
     }
 
     [Fact]
@@ -64,6 +65,37 @@ public async Task MerchantStatementDomainEventHandler_Handle_MerchantFeeSettledE
         result.IsSuccess.ShouldBeTrue();
     }
 
+    [Fact]
+    public async Task MerchantStatementDomainEventHandler_Handle_MerchantFeeSettledEvent_WrongExpectedRetried_EventIsHandled()
+    {
+        List<String> errors = new() { "WrongExpectedVersion" };
+
+        this.Mediator.SetupSequence(m => m.Send(It.IsAny<IRequest<Result>>(), It.IsAny<CancellationToken>()))
+            .ReturnsAsync(Result.Failure(errors))
+            .ReturnsAsync(Result.Success());
+
+        Result result = await this.EventHandler.Handle(TestData.DomainEvents.MerchantFeeSettledEvent, CancellationToken.None);
+        result.IsSuccess.ShouldBeTrue();
+        this.Mediator.Verify(m => m.Send(It.IsAny<IRequest<Result>>(), It.IsAny<CancellationToken>()), Times.Exactly(2));
+    }
+
+    [Fact]
+    public async Task MerchantStatementDomainEventHandler_Handle_MerchantFeeSettledEvent_WrongExpectedRetried_AllRetriesFailed()
+    {
+        List<String> errors = new() { "WrongExpectedVersion" };
+        this.Mediator.SetupSequence(m => m.Send(It.IsAny<IRequest<Result>>(), It.IsAny<CancellationToken>()))
+            .ReturnsAsync(Result.Failure(errors))
+            .ReturnsAsync(Result.Failure(errors))
+            .ReturnsAsync(Result.Failure(errors))
+            .ReturnsAsync(Result.Failure(errors))
+            .ReturnsAsync(Result.Failure(errors))
+            .ReturnsAsync(Result.Failure(errors));
+
+        Result result = await this.EventHandler.Handle(TestData.DomainEvents.MerchantFeeSettledEvent, CancellationToken.None);
+        result.IsFailed.ShouldBeTrue();
+        this.Mediator.Verify(m => m.Send(It.IsAny<IRequest<Result>>(), It.IsAny<CancellationToken>()), Times.Exactly(6));
+    }
+
     [Fact]
     public async Task MerchantStatementDomainEventHandler_Handle_StatementCreatedForDateEvent_EventIsHandled()
     {
diff --git a/TransactionProcessor.BusinessLogic/EventHandling/MerchantStatementDomainEventHandler.cs b/TransactionProcessor.BusinessLogic/EventHandling/MerchantStatementDomainEventHandler.cs
index a13ec2d1..d8ad31b5 100644
--- a/TransactionProcessor.BusinessLogic/EventHandling/MerchantStatementDomainEventHandler.cs
+++ b/TransactionProcessor.BusinessLogic/EventHandling/MerchantStatementDomainEventHandler.cs
@@ -1,22 +1,23 @@
-using System;
-using MediatR;
+using MediatR;
 using Polly;
+using Prometheus;
 using Shared.DomainDrivenDesign.EventSourcing;
+using Shared.EventStore.Aggregate;
 using Shared.EventStore.EventHandling;
+using Shared.Exceptions;
+using Shared.Logger;
+using Shared.ValueObjects;
 using SimpleResults;
+using System;
 using System.Diagnostics;
 using System.IO;
 using System.Net.Http;
 using System.Threading;
 using System.Threading.Tasks;
-using Prometheus;
-using Shared.Logger;
 using TransactionProcessor.BusinessLogic.Common;
 using TransactionProcessor.BusinessLogic.Requests;
 using TransactionProcessor.BusinessLogic.Services;
 using TransactionProcessor.DomainEvents;
-using Shared.EventStore.Aggregate;
-using Shared.ValueObjects;
 
 namespace TransactionProcessor.BusinessLogic.EventHandling
 {
@@ -144,12 +145,32 @@ private async Task<Result> HandleSpecificDomainEvent(MerchantDomainEvents.Withdr
         private async Task<Result> HandleSpecificDomainEvent(SettlementDomainEvents.MerchantFeeSettledEvent domainEvent,
                                                              CancellationToken cancellationToken)
         {
-            MerchantStatementCommands.AddSettledFeeToMerchantStatementCommand command = new(domainEvent.EstateId, domainEvent.MerchantId, domainEvent.FeeCalculatedDateTime, 
-                PositiveMoney.Create(Money.Create(domainEvent.CalculatedValue)), domainEvent.TransactionId, domainEvent.FeeId);
+            IAsyncPolicy<Result> retryPolicy = PolicyFactory.CreatePolicy(policyTag: "MerchantStatementDomainEventHandler - HandleSpecificDomainEvent<SettlementDomainEvents.MerchantFeeSettledEvent>");
+
+            try
+            {
+                return await PolicyFactory.ExecuteWithPolicyAsync(async () =>
+                {
+                    MerchantStatementCommands.AddSettledFeeToMerchantStatementCommand command = new(domainEvent.EstateId, domainEvent.MerchantId, domainEvent.FeeCalculatedDateTime,
+                        PositiveMoney.Create(Money.Create(domainEvent.CalculatedValue)), domainEvent.TransactionId, domainEvent.FeeId);
+
+                    Result result = await this.Mediator.Send(command, cancellationToken);
+                    return result;
+
+                }, retryPolicy, "MerchantStatementDomainEventHandler - HandleSpecificDomainEvent<SettlementDomainEvents.MerchantFeeSettledEvent>");
+            }
+            catch (Exception ex)
+            {
+                return Result.Failure(ex.GetExceptionMessages());
+            }
+            //MerchantStatementCommands.AddSettledFeeToMerchantStatementCommand command = new(domainEvent.EstateId, domainEvent.MerchantId, domainEvent.FeeCalculatedDateTime,
+            //    PositiveMoney.Create(Money.Create(domainEvent.CalculatedValue)), domainEvent.TransactionId, domainEvent.FeeId);
+
+            ////return await this.Mediator.Send(command, cancellationToken);
+            //Result result = await this.Mediator.Send(command, cancellationToken);
+            //return result;
+
 
-            //return await this.Mediator.Send(command, cancellationToken);
-            Result result = await this.Mediator.Send(command, cancellationToken);
-            return result;
         }
 
         #endregion