nice refactorings

PracticeCalendar.Application/PracticeEvents/Commands/AttendeeDeclineEventCommand.cs

@@ -0,0 +1,43 @@
+using MediatR;
+using PracticeCalendar.Domain.Common.Interfaces;
+using PracticeCalendar.Domain.Entities;
+using PracticeCalendar.Domain.Entities.Specifications;
+using PracticeCalendar.Domain.Exceptions;
+
+namespace PracticeCalendar.Application.PracticeEvents.Commands
+{
+    public record AttendeeDeclineEventCommand : IRequest
+    {
+        public AttendeeDeclineEventCommand(int eventId, int attendeeId)
+        {
+            EventId = eventId;
+            AttendeeId = attendeeId;
+        }
+
+        public int EventId { get; }
+        public int AttendeeId { get; }
+    }
+
+    public class AttendeeDeclineEventCommandHandler : IRequestHandler<AttendeeDeclineEventCommand>
+    {
+        private readonly IRepository<PracticeEvent> eventsRepo;
+
+        public AttendeeDeclineEventCommandHandler(IRepository<PracticeEvent> eventsRepo)
+        {
+            this.eventsRepo = eventsRepo;
+        }
+
+        public async Task<Unit> Handle(AttendeeDeclineEventCommand request, CancellationToken cancellationToken)
+        {
+            var spec = new PracticeEventByIdWithAttendees(request.EventId);
+            var practiceEvent = await eventsRepo.FirstOrDefaultAsync(spec, cancellationToken);
+            if (practiceEvent == null)
+            {
+                throw new PracticeEventNotFoundException();
+            }
+            practiceEvent.AttendeeDeclineEvent(request.AttendeeId);
+            
+            return Unit.Value;
+        }
+    }
+}