From 232f646c2e76f9e1c801e5fd89e01732246613ed Mon Sep 17 00:00:00 2001
From: StuartFerguson <stuart_ferguson1development@outlook.com>
Date: Tue, 7 Apr 2026 18:29:13 +0100
Subject: [PATCH] Refactor BuildStatement with improved validation and flow

Refactored the BuildStatement method to enhance structure, readability, and error handling. Introduced helper methods GetStatementAggregate and GetValidMerchant to encapsulate aggregate retrieval and validation logic. The new implementation ensures merchants exist and have addresses before building statements, and uses early returns for failure cases. The previous implementation was commented out and replaced with this improved version.
---
 .../MerchantStatementDomainService.cs         | 65 ++++++++++++++++++-
 1 file changed, 64 insertions(+), 1 deletion(-)

diff --git a/TransactionProcessor.BusinessLogic/Services/MerchantStatementDomainService.cs b/TransactionProcessor.BusinessLogic/Services/MerchantStatementDomainService.cs
index 62d81baf..1055cc6d 100644
--- a/TransactionProcessor.BusinessLogic/Services/MerchantStatementDomainService.cs
+++ b/TransactionProcessor.BusinessLogic/Services/MerchantStatementDomainService.cs
@@ -258,7 +258,7 @@ static String EncodeTo64(String toEncode)
             return returnValue;
         }
 
-        public async Task<Result> BuildStatement(MerchantStatementCommands.BuildMerchantStatementCommand command,
+        /*public async Task<Result> BuildStatement(MerchantStatementCommands.BuildMerchantStatementCommand command,
                                                  CancellationToken cancellationToken) {
             try {
                 // Work out the next statement date
@@ -300,6 +300,69 @@ public async Task<Result> BuildStatement(MerchantStatementCommands.BuildMerchant
             catch (Exception ex) {
                 return Result.Failure(ex.GetExceptionMessages());
             }
+        }*/
+
+        public async Task<Result> BuildStatement(MerchantStatementCommands.BuildMerchantStatementCommand command,
+                                                 CancellationToken cancellationToken)
+        {
+            try
+            {
+                Result<MerchantStatementAggregate> statementAggregate = await GetStatementAggregate(command, cancellationToken);
+                if (statementAggregate.IsFailed) return ResultHelpers.CreateFailure(statementAggregate);
+
+                Result<Merchant> merchant = await GetValidMerchant(statementAggregate.Data, cancellationToken);
+                if (merchant.IsFailed) return ResultHelpers.CreateFailure(merchant);
+
+                Result<String> htmlResult = await this.StatementBuilder.GetStatementHtml(statementAggregate.Data, merchant.Data, cancellationToken);
+                if (htmlResult.IsFailed) return ResultHelpers.CreateFailure(htmlResult);
+
+                String base64 = EncodeTo64(htmlResult.Data);
+
+                Result buildResult = statementAggregate.Data.BuildStatement(DateTime.Now, base64);
+                if (buildResult.IsFailed) return buildResult;
+
+                Result saveResult = await this.AggregateService.Save(statementAggregate.Data, cancellationToken);
+                if (saveResult.IsFailed) return saveResult;
+
+                return Result.Success();
+            }
+            catch (Exception ex)
+            {
+                return Result.Failure(ex.GetExceptionMessages());
+            }
+        }
+
+        private async Task<Result<MerchantStatementAggregate>> GetStatementAggregate(MerchantStatementCommands.BuildMerchantStatementCommand command,
+                                                                                     CancellationToken ct)
+        {
+            return await DomainServiceHelper.GetAggregateOrFailure(
+                c => this.AggregateService.GetLatest<MerchantStatementAggregate>(command.MerchantStatementId, c),
+                command.MerchantStatementId,
+                ct);
+        }
+
+        private async Task<Result<Merchant>> GetValidMerchant(MerchantStatementAggregate statementAggregate,
+                                                              CancellationToken ct)
+        {
+            MerchantStatement statement = statementAggregate.GetStatement();
+
+            Result<MerchantAggregate> merchantResult = await DomainServiceHelper.GetAggregateOrFailure(
+                c => this.AggregateService.Get<MerchantAggregate>(statement.MerchantId, c),
+                statement.MerchantId,
+                ct);
+
+            if (merchantResult.IsFailed)
+                return ResultHelpers.CreateFailure(merchantResult);
+
+            if (!merchantResult.Data.IsCreated)
+                return Result.Invalid("Merchant must be created to build a statement");
+
+            Merchant merchant = merchantResult.Data.GetMerchant();
+
+            if (!merchant.Addresses.Any())
+                return Result.Invalid("Merchant must have an address to build a statement");
+
+            return Result.Success(merchant);
         }
 
         public async Task<Result> RecordActivityDateOnMerchantStatement(MerchantStatementCommands.RecordActivityDateOnMerchantStatementCommand command,