From bcb2e79fa1cb72a94d75f1fc4be27290689a90ef Mon Sep 17 00:00:00 2001
From: TekH <h.tek@digitaldata.works>
Date: Fri, 29 Aug 2025 10:58:27 +0200
Subject: [PATCH] =?UTF-8?q?feat:=20Duplikatspr=C3=BCfung=20beim=20Erstelle?=
 =?UTF-8?q?n=20eines=20Empf=C3=A4ngers=20hinzuf=C3=BCgen?=
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- `CreateReceiverCommand` wurde aktualisiert, sodass nun `(Id, AlreadyExists)` anstelle von nur `Id` zurückgegeben wird.
- Der Handler wurde geändert, um zu überprüfen, ob bereits ein Empfänger mit derselben E-Mail-Adresse vorhanden ist.
- Es wird nur dann ein neuer Empfänger erstellt, wenn dieser noch nicht vorhanden ist.
- `Microsoft.EntityFrameworkCore` wurde für die Abfrageunterstützung hinzugefügt.
---
 .../Commands/CreateReceiverCommand.cs         | 19 ++++++++++++++-----
 .../HistoryTests.cs                           |  4 ++--
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/EnvelopeGenerator.Application/Receivers/Commands/CreateReceiverCommand.cs b/EnvelopeGenerator.Application/Receivers/Commands/CreateReceiverCommand.cs
index aa241bcf..434e0801 100644
--- a/EnvelopeGenerator.Application/Receivers/Commands/CreateReceiverCommand.cs
+++ b/EnvelopeGenerator.Application/Receivers/Commands/CreateReceiverCommand.cs
@@ -2,6 +2,7 @@
 using EnvelopeGenerator.Domain.Entities;
 using MediatR;
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.EntityFrameworkCore;
 using System.ComponentModel.DataAnnotations;
 using System.Security.Cryptography;
 using System.Text;
@@ -12,7 +13,7 @@ namespace EnvelopeGenerator.Application.Receivers.Commands;
 /// 
 /// </summary>
 [ApiExplorerSettings(IgnoreApi = true)]
-public record CreateReceiverCommand : IRequest<int>
+public record CreateReceiverCommand : IRequest<(int Id, bool AlreadyExists)>
 {
     /// <summary>
     /// 
@@ -51,7 +52,7 @@ public record CreateReceiverCommand : IRequest<int>
 /// <summary>
 /// 
 /// </summary>
-public class CreateReceiverCommandHandler : IRequestHandler<CreateReceiverCommand, int>
+public class CreateReceiverCommandHandler : IRequestHandler<CreateReceiverCommand, (int Id, bool AlreadyExists)>
 {
     /// <summary>
     /// 
@@ -73,9 +74,17 @@ public class CreateReceiverCommandHandler : IRequestHandler<CreateReceiverComman
     /// <param name="request"></param>
     /// <param name="cancel"></param>
     /// <returns></returns>
-    public async Task<int> Handle(CreateReceiverCommand request, CancellationToken cancel)
+    public async Task<(int Id, bool AlreadyExists)> Handle(CreateReceiverCommand request, CancellationToken cancel)
     {
-        Receiver receiver = await _repo.CreateAsync(request, cancel);
-        return receiver.Id;
+        var receiver = await _repo.ReadOnly()
+            .Where(r => r.EmailAddress == request.EmailAddress)
+            .SingleOrDefaultAsync(cancel);
+
+        var alreadyExists = receiver is not null;
+
+        if (!alreadyExists)
+            receiver = await _repo.CreateAsync(request, cancel);
+
+        return (receiver!.Id, alreadyExists);
     }
 }
\ No newline at end of file
diff --git a/EnvelopeGenerator.Tests.Application/HistoryTests.cs b/EnvelopeGenerator.Tests.Application/HistoryTests.cs
index 132fd614..7554a1d7 100644
--- a/EnvelopeGenerator.Tests.Application/HistoryTests.cs
+++ b/EnvelopeGenerator.Tests.Application/HistoryTests.cs
@@ -64,8 +64,8 @@ public class HistoryTests
             .Select(async email =>
             {
                 var cmd = new CreateReceiverCommand { EmailAddress = email };
-                var id = await Mediator.Send(cmd);
-                return (id, email);
+                var res = await Mediator.Send(cmd);
+                return (res.Id, email);
             })
         );
         _receivers.AddRange(receivers);