feat: E-Mail-Vorlagenverarbeitung hinzufügen

- Methode `FillTemplate` für Platzhalterersetzung hinzugefügt.
- `TemplatePlaceholderAttribute` eingeführt.
- `EmailOutService` mit Vorlagenmethoden aktualisiert.
- Unit-Tests für Vorlagenverarbeitung hinzugefügt.

DigitalData.EmailProfilerDispatcher.Application/Services/EmailOutService.cs

@@ -1,10 +1,13 @@
 using AutoMapper;
 using DigitalData.Core.Application;
+using DigitalData.Core.DTO;
 using DigitalData.EmailProfilerDispatcher.Application.Contracts;
 using DigitalData.EmailProfilerDispatcher.Application.DTOs.EmailOut;
+using DigitalData.EmailProfilerDispatcher.Domain.Attributes;
 using DigitalData.EmailProfilerDispatcher.Domain.Entities;
 using DigitalData.EmailProfilerDispatcher.Infrastructure.Contracts;
 using Microsoft.Extensions.Localization;
+using System.Reflection;
 
 namespace DigitalData.EmailProfilerDispatcher.Application.Services
 {
@@ -13,5 +16,36 @@ namespace DigitalData.EmailProfilerDispatcher.Application.Services
         public EmailOutService(IEmailOutRepository repository, IStringLocalizer<TResource> localizer, IMapper mapper) : base(repository, localizer, mapper)
         {
         }
-    }
+
+		public string ApplyTemplate(string template, params object[] models) => FillTemplate(template: template, models: models);
+
+		public async Task<DataResult<int>> CreateWithTemplateAsync(EmailOutCreateDto createDto, params object[] models)
+		{
+			createDto.EmailSubj = FillTemplate(createDto.EmailSubj, models);
+			createDto.EmailBody = FillTemplate(createDto.EmailBody, models);
+
+			return await base.CreateAsync(createDto);
+		}
+
+		public static string FillTemplate(string template, params object[] models)
+		{
+			foreach(var model in models)
+			{
+				var properties = model.GetType().GetProperties();
+
+				foreach (var property in properties)
+				{
+					var attribute = property.GetCustomAttribute<TemplatePlaceholderAttribute>();
+
+					if (attribute != null)
+					{
+						var value = property.GetValue(model)?.ToString();
+						template = template.Replace(attribute.Placeholder, value);
+					}
+				}
+			}
+
+			return template;
+		}
+	}
 }