from django.utils.translation import gettext as _
from django.utils import timezone

from rest_framework.response import Response
from rest_framework.permissions import AllowAny, IsAuthenticated
from rest_framework.exceptions import NotFound

from university.api.base import Endpoint
from university.api.bases.exam import ExamEndpoint
from university.models import Exam, Badge, OnlineExam
from university.forms import ExamRegistrateForm, ExamEnrollForm


class ExamListEndpoint(Endpoint):

    permission_classes = (AllowAny, )

    def get(self, request, *args, **kwargs):
        exams = [{
            'id': exam.id,
            'name': exam.name,
            'description': exam.description,
            'price': exam.price,
            'registration_start': exam.registration_start.strftime('%Y-%m-%d %H:%M:%S'),
            'registration_deadline': exam.registration_deadline.strftime('%Y-%m-%d %H:%M:%S'),
            'venues': exam.venues,
            'exam_times': exam.exam_times,
            'required': exam.required_permissions_desc
        } for exam in Exam.objects.all()]
        return Response({
            'detail': _('success'),
            'datas': {
                'notice': '**日期:**   2020 年 9 月 26 日(暂定)  \n**城市:** 北京、上海、深圳，具体考点 9 月 16 日前通知  \n**时间:**  \n上午 10:00 - 11:00 PCTA  \n下午 13:30 - 14:45 PCTP 理论  \nPCTP 上机考试将调整为一个季度进行一次',
                'exams': exams
            }
        })


class ExamDetailEndpoint(ExamEndpoint):

    permission_classes = (AllowAny, )

    def get(self, request, *args, **kwargs):
        exam = kwargs['exam']
        return Response({
            'detail': _('success'),
            'datas': {
                'id': exam.id,
                'name': exam.name,
                'description': exam.description,
                'price': exam.price,
                'registration_start': exam.registration_start.strftime('%Y-%m-%d %H:%M:%S'),
                'registration_deadline': exam.registration_deadline.strftime('%Y-%m-%d %H:%M:%S'),
                'venues': exam.venues,
                'exam_times': exam.exam_times,
                'required': exam.required_permissions_desc
            }
        })


class RegistrationCheckEndpoint(ExamEndpoint):

    permission_classes = (IsAuthenticated, )

    def get(self, request, *args, **kwargs):
        exam = kwargs['exam']
        user = request.user

        is_permitted = True
        is_registrated = False
        required = []

        missed_badges = set(exam.required_badges) \
            - set(user.userbadge_set.values_list('id', flat=True))

        if missed_badges:
            is_permitted = False
            required = Badge.objects.filter(id__in=missed_badges)\
                                    .values_list('description', flat=True)

        if user.userexam_set.filter(exam=exam).exists():
            is_registrated = True

        return Response({
            'detail': _('success'),
            'datas': {
                'is_registrated': is_registrated,
                'is_permitted': is_permitted,
                'required': required
            }
        })


class RegistrateEndpoint(ExamEndpoint):

    permission_classes = (IsAuthenticated, )

    def post(self, request, *args, **kwargs):
        form = ExamRegistrateForm(user=request.user, exam=kwargs['exam'], data=request.data)
        if not form.is_valid():
            return Response({
                'detail': _('wrong params'),
                'errors': form.errors,
                'is_permitted': form.is_permitted,
                'required': form.required
            }, status=400)

        form.save()
        return Response({
            'detail': _('success')
        })


class ExamPCTAEnrollEndpoint(Endpoint):

    permission_classes = (IsAuthenticated, )

    def convert_args(self, request, exam_flag, *args, **kwargs):
        if exam_flag not in ['PCTA', 'PCTP']:
            raise NotFound
        kwargs['exam_flag'] = exam_flag
        return (args, kwargs)

    def get(self, request, exam_flag, *args, **kwargs):
        available_sessions = []
        now = timezone.now()
        for exam in OnlineExam.objects.filter(
                flag=exam_flag,
                registration_deadline__gt=now):
            exam_start_at = timezone.localtime(exam.start_at)
            exam_end_at = timezone.localtime(exam.end_at)
            available_sessions.append({
                'display': '{} ~ {}'.format(
                    exam_start_at.strftime('%Y年%m月%d日 %H:%M'),
                    exam_end_at.strftime('%H:%M')),
                'start_at': exam_start_at.strftime('%Y-%m-%d %H:%M:%S%z'),
                'end_at': exam_end_at.strftime('%Y-%m-%d %H:%M:%S%z'),
                'exam_id': exam.id
            })
        return Response({
            'detail': _('success'),
            'data': {
                'available_sessions': available_sessions
            }
        })

    def post(self, request, exam_flag, *args, **kwargs):
        form = ExamEnrollForm(
            exam_flag=exam_flag, user=request.user, data=request.data)
        if not form.is_valid():
            return Response({
                'detail': _('wrong params'),
                'errors': form.errors,
            }, status=400)
        form.save()
        return Response({
            'detail': _('success')
        })