svthalia/concrexit

from django.utils import timezone

from rest_framework import filters, viewsets
from rest_framework.decorators import action
from rest_framework.exceptions import PermissionDenied
from rest_framework.generics import get_object_or_404
from rest_framework.permissions import IsAuthenticated, IsAuthenticatedOrReadOnly
from rest_framework.response import Response
from rest_framework.settings import api_settings

from events import services
from events.api.v1.serializers import (
    EventListSerializer,
    EventRegistrationAdminListSerializer,
    EventRegistrationListSerializer,
    EventRegistrationSerializer,
    EventRetrieveSerializer,
)
from events.exceptions import RegistrationError
from events.models import Event, EventRegistration
from utils.snippets import extract_date_range


class EventViewset(viewsets.ReadOnlyModelViewSet):
    """Define the viewset for events, requires an authenticated user and enables ordering on the event start/end."""

    queryset = Event.objects.filter(published=True)
    permission_classes = [IsAuthenticatedOrReadOnly]
    filter_backends = (
        filters.OrderingFilter,
        filters.SearchFilter,
    )
    ordering_fields = ("start", "end")
    search_fields = ("title",)

    def get_queryset(self):
        queryset = Event.objects.filter(published=True)

        if (
            self.action == "retrieve"
            or api_settings.SEARCH_PARAM in self.request.query_params
        ):
            return queryset

        start, end = extract_date_range(self.request, allow_empty=True)

        if start is not None:
            queryset = queryset.filter(start__gte=start)
        if end is not None:
            queryset = queryset.filter(end__lte=end)
        if start is None and end is None:
            queryset = queryset.filter(end__gte=timezone.now())

        return queryset

    def get_serializer_class(self):
        if self.action == "retrieve":
            return EventRetrieveSerializer
        return EventListSerializer

    @action(detail=True, methods=["get", "post"], permission_classes=(IsAuthenticated,))
    def registrations(self, request, pk):
        """Define a custom route for the event's registrations, can filter on registration status if the user is an organiser.

        :param request: the request object
        :param pk: the primary key of the event
        :return: the registrations of the event
        """
        event = get_object_or_404(Event, pk=pk)

        if request.method.lower() == "post":
            try:
                registration = services.create_registration(request.member, event)
                serializer = EventRegistrationSerializer(
                    instance=registration, context={"request": request}
                )
                return Response(status=201, data=serializer.data)
            except RegistrationError as e:
                raise PermissionDenied(detail=e) from e

        status = request.query_params.get("status", None)

        # Make sure you can only access other registrations when you have
        # the permissions to do so
        context = {"request": request}
        if services.is_organiser(self.request.member, event):
            queryset = EventRegistration.objects.filter(event=pk)
            if status == "queued":
                queryset = EventRegistration.objects.filter(
                    event=pk, date_cancelled=None
                )[event.max_participants :]
            elif status == "cancelled":
                queryset = EventRegistration.objects.filter(
                    event=pk, date_cancelled__not=None
                )
            elif status == "registered":
                queryset = EventRegistration.objects.filter(
                    event=pk, date_cancelled=None
                )[: event.max_participants]

            serializer = EventRegistrationAdminListSerializer(
                queryset, many=True, context=context
            )
        else:
            serializer = EventRegistrationListSerializer(
                EventRegistration.objects.filter(event=pk, date_cancelled=None)[
                    : event.max_participants
                ],
                many=True,
                context=context,
            )

        return Response(serializer.data)