Refactor email template handling and error management

- Updated EmailTemplateDto to allow mutable Body and Subject properties.
- Implemented IRequest interface in UpdateEmailTemplateCommand for MediatR.
- Enhanced error handling in EmailTemplateController with NotFoundException.
- Introduced UpdateEmailTemplateCommandHandler for processing update commands.
- Added NotFoundException class for improved error handling.

EnvelopeGenerator.Application/DTOs/EmailTemplateDto.cs

@@ -22,11 +22,11 @@ namespace EnvelopeGenerator.Application.DTOs
         /// <summary>
         /// 
         /// </summary>
-        public required string Body { get; init; }
+        public required string Body { get; set; }
 
         /// <summary>
         /// 
         /// </summary>
-        public required string Subject { get; init; }
+        public required string Subject { get; set; }
     };
 }

EnvelopeGenerator.Application/EmailTemplates/Commands/Update/UpdateEmailTemplateCommand.cs

@@ -1,4 +1,5 @@
-using System.Text.Json.Serialization;
+using MediatR;
+using System.Text.Json.Serialization;
 
 namespace EnvelopeGenerator.Application.EmailTemplates.Commands.Update;
 
@@ -12,7 +13,7 @@ namespace EnvelopeGenerator.Application.EmailTemplates.Commands.Update;
 /// <param name="Subject">
 /// (Optional) Der neue Betreff der E-Mail. Wenn null, bleibt der vorhandene Betreff unverändert.
 /// </param>
-public record UpdateEmailTemplateCommand(string? Body = null, string? Subject = null)
+public record UpdateEmailTemplateCommand(string? Body = null, string? Subject = null) : IRequest
 {
     /// <param>
     /// Die Abfrage, die die E-Mail-Vorlage darstellt, die aktualisiert werden soll.

EnvelopeGenerator.Application/EmailTemplates/Commands/Update/UpdateEmailTemplateCommandHandler.cs

@@ -0,0 +1,43 @@
+using DigitalData.Core.Abstractions.Infrastructure;
+using EnvelopeGenerator.Application.DTOs;
+using EnvelopeGenerator.Application.Exceptions;
+using EnvelopeGenerator.Domain.Entities;
+using MediatR;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.EntityFrameworkCore;
+
+namespace EnvelopeGenerator.Application.EmailTemplates.Commands.Update;
+
+/// <summary>
+/// 
+/// </summary>
+public class UpdateEmailTemplateCommandHandler : IRequestHandler<UpdateEmailTemplateCommand>
+{
+    private readonly IRepository<EmailTemplate> _repository;
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="repository"></param>
+    public UpdateEmailTemplateCommandHandler(IRepository<EmailTemplate> repository)
+    {
+        _repository = repository;
+    }
+
+    public async Task Handle(UpdateEmailTemplateCommand request, CancellationToken cancel)
+    {
+        var temp = (request.EmailTemplateQuery?.Id is int id
+            ? await _repository.ReadOrDefaultAsync<EmailTemplateDto>(t => t.Id == id, single: false, cancel)
+            : request!.EmailTemplateQuery!.Type is Common.Constants.EmailTemplateType type
+                ? await _repository.ReadOrDefaultAsync<EmailTemplateDto>(t => t.Name == type.ToString(), single: false, cancel)
+                : throw new InvalidOperationException("Both id and type is null. Id: " + request.EmailTemplateQuery.Id + ". Type: " + request.EmailTemplateQuery.Type.ToString())) ?? throw new NotFoundException();
+
+        if(request.Body is not null)
+            temp.Body = request.Body;
+
+        if (request.Subject is not null)
+            temp.Subject = request.Subject;
+
+        await _repository.UpdateAsync(temp, t => t.Id == temp.Id, cancel);
+    }
+}

EnvelopeGenerator.Application/Exceptions/NotFoundException.cs

@@ -0,0 +1,12 @@
+namespace EnvelopeGenerator.Application.Exceptions;
+
+public class NotFoundException : Exception
+{
+    public NotFoundException()
+    {
+    }
+
+    public NotFoundException(string? message) : base(message)
+    {
+    }
+}

EnvelopeGenerator.GeneratorAPI/Controllers/EmailTemplateController.cs

@@ -10,6 +10,7 @@ using EnvelopeGenerator.Application.DTOs;
 using MediatR;
 using System.Threading.Tasks;
 using DigitalData.UserManager.Application.Services;
+using EnvelopeGenerator.Application.Exceptions;
 
 namespace EnvelopeGenerator.GeneratorAPI.Controllers;
 
@@ -116,11 +117,16 @@ public class EmailTemplateController : ControllerBase
             }
             else
             {
-                update.EmailTemplateQuery = email;
+                var reset = _mapper.Map<ResetEnvelopeTemplateCommand>(email);
-                // Logic for updating the email template
+                await _mediator.Send(update);
+                return Ok();
             }
 
         }
+        catch(NotFoundException)
+        {
+            return BadRequest();
+        }
         catch (Exception ex)
         {
             _logger.LogError(ex, "An unexpected error occurred. {message}", ex.Message);