From 17ef988cff104fd04049a9b275a06bc47ecf8bc6 Mon Sep 17 00:00:00 2001
From: Jur Balledux <jurjean@gmail.com>
Date: Mon, 29 Jul 2024 14:56:45 +0200
Subject: [PATCH] Aggregate: Pre process in applied scope (#44)

Co-authored-by: Jur Balledux <j.balledux@tjip.com>
---
 props/common.props                            |  2 +-
 .../Aggregate_TAggregate.cs                   | 11 +++--
 .../Qowaiv.DomainModel.csproj                 |  4 +-
 .../Event_sourced_aggregate_specs.cs          | 45 ++++++++++++++++++-
 4 files changed, 55 insertions(+), 7 deletions(-)

diff --git a/props/common.props b/props/common.props
index dd25279..55d5e8d 100644
--- a/props/common.props
+++ b/props/common.props
@@ -3,7 +3,7 @@
 
   <PropertyGroup>
     <Description>Qowaiv implements common, universal domain objects. These types form the base of your domain model.</Description>
-    <Authors>Ad van der Hoeven;Corniel Nobel;Erik Ammerlaan;Jack Kester;Marcel Strik;Mitchell Smit;Patrick Evers;Wilko Frieke</Authors>
+    <Authors>Ad van der Hoeven;Corniel Nobel;Erik Ammerlaan;Jack Kester;Jur Balledux;Marcel Strik;Mitchell Smit;Patrick Evers;Wilko Frieke</Authors>
     <Owners>Qowaiv community</Owners>
     <PackageTags>qowaiv domain model</PackageTags>
     <Company>Qowaiv community</Company>
diff --git a/src/Qowaiv.DomainModel/Aggregate_TAggregate.cs b/src/Qowaiv.DomainModel/Aggregate_TAggregate.cs
index 9f92ec3..7168f0a 100644
--- a/src/Qowaiv.DomainModel/Aggregate_TAggregate.cs
+++ b/src/Qowaiv.DomainModel/Aggregate_TAggregate.cs
@@ -59,11 +59,14 @@ protected Result<TAggregate> ApplyEvents(params object[] events)
     [Pure]
     protected Result<TAggregate> Apply(IEnumerable<object> events)
     {
-        Guard.NotNull(events, nameof(events));
-
         var updated = Clone();
-        var append = AppendOnlyCollection.Empty.Add(events.Select(PreProcessEvent));
-        updated.Replay(append);
+        var append = AppendOnlyCollection.Empty;
+
+        foreach (var @event in Guard.NotNull(events, nameof(events)).Select(updated.PreProcessEvent))
+        {
+            updated.Dispatcher.When(@event);
+            append = append.Add(@event);
+        }
 
         var result = updated.Validator.Validate(updated);
         if (result.IsValid)
diff --git a/src/Qowaiv.DomainModel/Qowaiv.DomainModel.csproj b/src/Qowaiv.DomainModel/Qowaiv.DomainModel.csproj
index b2986d4..152baf9 100644
--- a/src/Qowaiv.DomainModel/Qowaiv.DomainModel.csproj
+++ b/src/Qowaiv.DomainModel/Qowaiv.DomainModel.csproj
@@ -6,9 +6,11 @@
     <TargetFrameworks>netstandard2.0;net5.0;net6.0;net7.0;net8.0</TargetFrameworks>
     <OutputType>library</OutputType>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
-    <Version>1.1.1</Version>
+    <Version>1.1.2</Version>
     <PackageId>Qowaiv.DomainModel</PackageId>
     <PackageReleaseNotes>
+v1.1.2
+- Aggregate: PreProcessEvent in applied scope. #44
 v1.1.1
 - CommandProcessor made thread-safe. #42
 v1.1.0
diff --git a/test/Qowaiv.DomainModel.UnitTests/Event_sourced_aggregate_specs.cs b/test/Qowaiv.DomainModel.UnitTests/Event_sourced_aggregate_specs.cs
index d264a7a..e7fc75b 100644
--- a/test/Qowaiv.DomainModel.UnitTests/Event_sourced_aggregate_specs.cs
+++ b/test/Qowaiv.DomainModel.UnitTests/Event_sourced_aggregate_specs.cs
@@ -1,4 +1,5 @@
-using Qowaiv.DomainModel;
+using NUnit.Framework.Internal.Execution;
+using Qowaiv.DomainModel;
 
 namespace Event_sourced_aggregate_specs
 {
@@ -70,6 +71,21 @@ public void skips_unknown_event_types()
             var updated = aggregate.TestApplyChange(new NameUpdated("unknown")).Should().BeValid().Value;
             updated.Version.Should().Be(1);
         }
+
+        [Test]
+        public void pre_processed_in_applied_scope()
+        {
+            var aggregate = new TestPreProcessEventAggregate();
+            var updated = aggregate
+                .TestPreprocessEvents(new NameUpdated("Jimi Hendrix"), new NameUpdated("unknown"))
+                .Should().BeValid().Value;
+
+            updated.Buffer.Uncommitted.Should().BeEquivalentTo(new object[]
+            {
+                new NameUpdated("Jimi Hendrix"),
+                new NameUpdated("Jimi Hendrix"),
+            });
+        }
     }
 
     internal class TestApplyChangeAggregate : Aggregate<TestApplyChangeAggregate, Guid>
@@ -79,4 +95,31 @@ public TestApplyChangeAggregate()
 
         public Result<TestApplyChangeAggregate> TestApplyChange(object @event) => ApplyEvent(@event);
     }
+
+    internal class TestPreProcessEventAggregate : Aggregate<TestPreProcessEventAggregate, Guid>
+    {
+        private string Name = string.Empty;
+        
+        public TestPreProcessEventAggregate()
+            : base(Guid.NewGuid(), Qowaiv.Validation.Abstractions.Validator.Empty<TestPreProcessEventAggregate>()) { }
+
+        public Result<TestPreProcessEventAggregate> TestPreprocessEvents(params object[] events) => ApplyEvents(events);
+
+        protected override object PreProcessEvent(object @event)
+        {
+            if (@event is not NameUpdated e)
+            {
+                return @event;
+            }
+
+            var newName = Name == string.Empty ? e.Name : Name;
+            return new NameUpdated(newName);
+        }
+
+
+        internal void When(NameUpdated @event)
+        {
+            Name = @event.Name;
+        }
+    }
 }