"""Product app back-office views."""
from django.conf import settings
from django.db.transaction import on_commit
from django.shortcuts import get_object_or_404
from rest_framework import generics, status, permissions
from rest_framework.response import Response

from gallery.tasks import delete_image
from product import serializers, models


class ProductBackOfficeMixinView:
    """Product back-office mixin view."""

    permission_classes = (permissions.IsAuthenticated,)
    queryset = models.Product.objects.with_base_related() \
        .order_by('-created', )


class ProductBackOfficeGalleryCreateDestroyView(ProductBackOfficeMixinView,
                                                generics.CreateAPIView,
                                                generics.DestroyAPIView):
    """Resource for a create gallery for product for back-office users."""
    serializer_class = serializers.ProductBackOfficeGallerySerializer

    def get_object(self):
        """
        Returns the object the view is displaying.
        """
        product_qs = self.filter_queryset(self.get_queryset())

        product = get_object_or_404(product_qs, pk=self.kwargs['pk'])
        gallery = get_object_or_404(product.product_gallery, image_id=self.kwargs['image_id'])

        # May raise a permission denied
        self.check_object_permissions(self.request, gallery)

        return gallery

    def create(self, request, *args, **kwargs):
        """Overridden create method"""
        super().create(request, *args, **kwargs)
        return Response(status=status.HTTP_201_CREATED)

    def destroy(self, request, *args, **kwargs):
        """Override destroy method."""
        gallery_obj = self.get_object()
        if settings.USE_CELERY:
            on_commit(lambda: delete_image.delay(image_id=gallery_obj.image.id,
                                                 completely=False))
        else:
            on_commit(lambda: delete_image(image_id=gallery_obj.image.id,
                                           completely=False))
        # Delete an instances of ProductGallery model
        gallery_obj.delete()
        return Response(status=status.HTTP_204_NO_CONTENT)


class ProductBackOfficeGalleryListView(ProductBackOfficeMixinView, generics.ListAPIView):
    """Resource for returning gallery for product for back-office users."""
    serializer_class = serializers.ProductImageSerializer

    def get_object(self):
        """Override get_object method."""
        qs = super(ProductBackOfficeGalleryListView, self).get_queryset()
        product = get_object_or_404(qs, pk=self.kwargs['pk'])

        # May raise a permission denied
        self.check_object_permissions(self.request, product)

        return product

    def get_queryset(self):
        """Override get_queryset method."""
        return self.get_object().gallery.all()