from rest_framework import viewsets
from rest_framework.response import Response

# https://gist.github.com/ivlevdenis/a0c8f5b472b6b8550bbb016c6a30e0be


class ExtendViewSet(object):
    """
    This viewset mixin class with extended options list.
    """
    permission_map = {}
    throttle_scope_map = {}
    serializer_class_map = {}

    def get_serializer_class(self):
        ser = self.serializer_class_map.get(self.action, None)
        self.serializer_class = ser or self.serializer_class
        return super().get_serializer_class()

    def initialize_request(self, request, *args, **kwargs):
        request = super().initialize_request(request, *args, **kwargs)
        throttle_scope = self.throttle_scope_map.get(self.action, None)
        cls_throttle_scope = getattr(self, 'throttle_scope', None)
        self.throttle_scope = throttle_scope or cls_throttle_scope or ''
        return request

    def get_permissions(self):
        perms = self.permission_map.get(self.action, None)
        if perms and not isinstance(perms, (tuple, list)):
            perms = [perms, ]
        self.permission_classes = perms or self.permission_classes
        return super().get_permissions()

    def options(self, request, *args, **kwargs):
        if self.metadata_class is None:
            return self.http_method_not_allowed(request, *args, **kwargs)
        data = self.metadata_class().determine_metadata(request, self)
        data['actions']['GET'] = self.query_metadata
        return Response(data, status=status.HTTP_200_OK)


class ExtendedModelViewSet(ExtendViewSet, viewsets.ModelViewSet):
    pass


class BothListFormatMixin:

    def list(self, request, *args, **kwargs):
        queryset = self.filter_queryset(self.get_queryset())

        if request.query_params.get('page'):
            page = self.paginate_queryset(queryset)
            if page is not None:
                serializer = self.get_serializer(page, many=True)
                return self.get_paginated_response(serializer.data)
            else:
                return Response({'results': []})

        serializer = self.get_serializer(queryset, many=True)
        return Response(serializer.data)