from django.db.models import Q
from rest_framework import generics, status
from rest_framework.permissions import BasePermission, IsAuthenticated, SAFE_METHODS
from rest_framework.response import Response

from .models import Event
from .serializers import EventSerializer, EventCreateSerializer, EventUpdateSerializer


class IsEventCreatorOrReadOnly(BasePermission):
    message = 'Seul le créateur peut modifier ou supprimer cet événement.'

    def has_object_permission(self, request, view, obj):
        return request.method in SAFE_METHODS or obj.created_by_id == request.user.pk


class VisibleEventsMixin:
    def get_queryset(self):
        return Event.objects.filter(
            Q(is_public=True) | Q(created_by=self.request.user)
        ).order_by('start_date', 'start_time', 'pk')


class EventListView(VisibleEventsMixin, generics.ListCreateAPIView):
    serializer_class = EventSerializer
    permission_classes = [IsAuthenticated]

    def create(self, request, *args, **kwargs):
        serializer = EventCreateSerializer(
            data=request.data, context=self.get_serializer_context(),
        )
        serializer.is_valid(raise_exception=True)
        event = serializer.save(created_by=request.user)
        return Response(
            EventSerializer(event, context=self.get_serializer_context()).data,
            status=status.HTTP_201_CREATED,
        )


class EventDetailView(VisibleEventsMixin, generics.RetrieveUpdateDestroyAPIView):
    serializer_class = EventSerializer
    permission_classes = [IsAuthenticated, IsEventCreatorOrReadOnly]
    lookup_url_kwarg = 'id'

    def update(self, request, *args, **kwargs):
        partial = kwargs.pop('partial', False)
        instance = self.get_object()
        serializer = EventUpdateSerializer(
            instance, data=request.data, partial=partial,
            context=self.get_serializer_context(),
        )
        serializer.is_valid(raise_exception=True)
        self.perform_update(serializer)
        return Response(
            EventSerializer(serializer.instance, context=self.get_serializer_context()).data,
        )

    def destroy(self, request, *args, **kwargs):
        self.perform_destroy(self.get_object())
        return Response(
            {'message': 'Event deleted successfully'},
            status=status.HTTP_200_OK,
        )


class EventCreateView(EventListView):
    http_method_names = ['post', 'options']
    serializer_class = EventCreateSerializer