DEV-701 Event attendees

backend/config/urls.py

@@ -19,11 +19,13 @@
 from django.urls import path
 
 from hoagiecalendar.api.event_views import EventDetailView, EventView
+from hoagiecalendar.api.user_event_attending_view import UserEventAttendingView
 from hoagiecalendar.api.user_events_view import UserEventsView
 
 urlpatterns = [
 	path("admin/", admin.site.urls),
 	path("event/", EventView.as_view(), name="event"),
 	path("event/<int:event_id>/", EventDetailView.as_view(), name="event-detail"),
-	path("user/events/", UserEventsView.as_view(), name="user-events"),
+	path("user/events/created", UserEventsView.as_view(), name="user-events"),
+	path("user/events/attending", UserEventAttendingView.as_view(), name="user-events-attending"),
 ]

backend/hoagiecalendar/api/event_views.py

@@ -37,6 +37,11 @@ class EventSerializer(serializers.ModelSerializer):
 		},
 	)
 
+	attending_count = serializers.SerializerMethodField(read_only=True)
+
+	def get_attending_count(self, obj: Event) -> int:
+		return obj.attending_count()
+
 	class Meta:
 		model = Event
 		fields = [
@@ -50,9 +55,9 @@ class Meta:
 			"owner",
 			"category",
 			"from_mail",
-			"ordering",
+			"attending_count",
 		]
-		read_only_fields = ["id", "owner", "created_at", "updated_at"]
+		read_only_fields = ["id", "owner", "created_at", "updated_at", "attending_count"]
 
 
 class EventView(APIView):

backend/hoagiecalendar/api/user_event_attending_view.py

@@ -0,0 +1,49 @@
+from rest_framework import status
+from rest_framework.request import Request
+from rest_framework.response import Response
+from rest_framework.views import APIView
+
+from hoagiecalendar.models.user import User
+
+from ..models.event import Event
+from .event_views import EventSerializer
+
+
+def add_or_remove_attendee_from_event(event_id: str | None, user: User, add: bool) -> Response:
+	if not event_id:
+		return Response({"error": "invalid request: no event_id provided"}, status=status.HTTP_400_BAD_REQUEST)
+
+	try:
+		event = Event.objects.get(pk=event_id)
+		if add:
+			event.attendees.add(user)
+			serializer = EventSerializer(event)
+
+			return Response({"event": serializer.data}, status=status.HTTP_200_OK)
+		else:
+			event.attendees.remove(user)
+
+			return Response(status=status.HTTP_204_NO_CONTENT)
+	except ValueError:
+		return Response({"error": "invalid event_id"}, status=status.HTTP_400_BAD_REQUEST)
+	except Event.DoesNotExist:
+		return Response({"error": "event not found"}, status=status.HTTP_404_NOT_FOUND)
+	except Exception as _:
+		# TODO: Log exception once logging is set up
+		return Response({"error": "an internal error has occurred"}, status=status.HTTP_500_INTERNAL_SERVER_ERROR)
+
+
+class UserEventAttendingView(APIView):
+	def post(self, request: Request) -> Response:
+		return add_or_remove_attendee_from_event(
+			event_id=request.query_params.get("event_id"),
+			user=request.user,
+			add=True,
+		)
+
+	def delete(self, request: Request) -> Response:
+		return add_or_remove_attendee_from_event(
+			event_id=request.query_params.get("event_id"),
+			user=request.user,
+			add=False,
+		)

backend/hoagiecalendar/models/event.py

@@ -25,6 +25,10 @@ class Event(models.Model):
 	from_mail = models.BooleanField(default=False)
 	created_at = models.DateTimeField(auto_now_add=True)
 	updated_at = models.DateTimeField(auto_now=True)
+	attendees = models.ManyToManyField(User, related_name="events_attending", blank=True)
+
+	def attending_count(self) -> int:
+		return self.attendees.count()
 
 	def __str__(self) -> str:
 		return self.name