from django.utils.translation import gettext as _
from django.db.models import Sum

from rest_framework.response import Response
from rest_framework.permissions import AllowAny

from university.api.bases.course import CourseEndpoint


class ChapterListEndpoint(CourseEndpoint):

    permission_classes = (AllowAny, )

    def get(self, request, *args, **kwargs):
        course = kwargs['course']
        datas = []
        for chapter in course.chapter_set.all().order_by('sequence'):
            datas.append({
                'title': chapter.title,
                'description': chapter.description,
                'slug': chapter.slug,
                'periods': chapter.lesson_set.aggregate(Sum('periods'))['periods__sum']
            })
        return Response({'detail': _('success'), 'datas': datas})