from rest_framework.exceptions import NotFound

from university.api.base import Endpoint
from university.models import Chapter


class ChapterEndpoint(Endpoint):

    def convert_args(self, request, course_slug, chapter_slug, *args, **kwargs):
        try:
            chapter = Chapter.objects.select_related('course').get(
                slug=chapter_slug,
                course__slug=course_slug)
            course = chapter.course
        except Chapter.DoesNotExist:
            raise NotFound

        if not (course.visable_when_no_perm or request.user.has_course(course)):
            raise NotFound

        self.check_object_permissions(request, chapter)

        kwargs['course'] = chapter.course
        kwargs['chapter'] = chapter
        return (args, kwargs)