import csv
import datetime

from django.contrib.auth import get_user_model
from django.core.exceptions import ValidationError
from django.http import HttpResponse
from rest_framework.permissions import IsAuthenticated
from rest_framework.renderers import JSONRenderer
from rest_framework.response import Response
from rest_framework.views import APIView

from progress.models import ProgressLesson, Progress
from progress.serializers import ProgressAnalyticSerializer, ProgressLessonSerializer
from courses.api import CourseProgressApi
from progress.tasks import add_next_lesson


class CourseProgressDynamicView(APIView):
    renderer_classes = (JSONRenderer,)

    @staticmethod
    def get(request, token):
        if request.user.is_authenticated() and request.user.is_staff:
            try:
                progresses = Progress.objects.filter(course_token=token)
                res = {}
                for i in progresses:
                    key = i.progresslesson_set.filter(status="done").count()
                    res[key] = 1 if not key in res.keys() else res[key] + 1
                return Response(res, status=200)
            except ValidationError:
                return Response("Bad request", status=400)

        return Response(status=403)


class CourseProgressUserView(APIView):
    renderer_classes = (JSONRenderer,)

    @staticmethod
    def get(request, token):
        if request.user.is_authenticated() and request.user.is_staff:
            try:
                res = []
                sorted_token_list = CourseProgressApi.get_topic_lesson(token)
                for p in Progress.objects.filter(course_token=token):
                    progress = ProgressAnalyticSerializer(p).data
                    progress['progress_course'] = p.progress_status(sorted_token_list)
                    res.append(progress)
                return Response(res, status=200)
            except ValidationError:
                return Response("Bad request", status=400)

        return Response(status=403)


class UpdateProgress(APIView):
    renderer_classes = (JSONRenderer,)

    @staticmethod
    def post(request):
        """
            На вход обязательно передаётся параметр id (id узла).
        """
        lesson_token = request.JSON.get('lesson_token', None)
        course_token = request.JSON.get('course_token', None)
        student_out_key = request.JSON.get('student_out_key', None)
        action = request.JSON.get('action', 'wait')
        comment = request.JSON.get('comment', None)

        if lesson_token is None or course_token is None:
            return Response('Не передан слаг курса или токен урока', status=400)
        try:
            is_student = student_out_key is None
            student = request.user if is_student else get_user_model().objects.get(out_key=student_out_key)

            if is_student:
                p = Progress.objects.get(user=student, course_token=course_token)
            else:
                p = Progress.objects.get(
                    user=student,
                    teacher=request.user,
                    course_token=course_token,
                )

            if p.active_lesson == lesson_token:
                return Response("Ошибка доступа", status=403)

            try:
                pv = ProgressLesson.objects.get(
                    progress=p,
                    lesson_token=p.active_lesson,
                )

                if is_student and pv.status == ProgressLesson.STATUSES.fail and action == "wait":
                    pv.status = ProgressLesson.STATUSES.wait

                elif not is_student and pv.status == ProgressLesson.STATUSES.wait:
                    pv.status = action

                else:
                    return Response("Ошибка прав доступа", status=403)

                pv.comment_tokens.append(comment)

            except ProgressLesson.DoesNotExist:
                pv = ProgressLesson.objects.create(
                    date=datetime.datetime.now(),
                    teacher=p.teacher,
                    progress=p,
                    lesson_token=p.active_lesson,
                    status=ProgressLesson.STATUSES.done
                )

            pv.save()

            if pv.status == ProgressLesson.STATUSES.done:
                #TODO: Ассинхроннаязадача для celery
                add_next_lesson(p)

            return Response(ProgressLessonSerializer(pv).data, status=200)

        except Progress.DoesNotExist:
            return Response('Не найден прогресс по заданным параметрам', status=404)


class UploadCourseProgressUserView(APIView):
    renderer_classes = (JSONRenderer,)

    @staticmethod
    def get(request, token):
        if request.user.is_authenticated() and request.user.is_staff:
            try:
                response = HttpResponse(content_type='text/csv')
                response['Content-Disposition'] = 'attachment; filename="%s.csv"' % token
                sorted_token_list = CourseProgressApi.get_topic_lesson(token)
                writer = csv.writer(response)
                writer.writerow(['Имя', 'Почта', 'Последняя тема', 'Последний урок'])

                for p in Progress.objects.filter(course_token=token):
                    progress = ProgressAnalyticSerializer(p).data
                    progress['progress_course'] = p.progress_status(sorted_token_list)
                    writer.writerow([
                        progress['name'],
                        progress['email'],
                        progress['progress_course'] and progress['progress_course'][0],
                        progress['progress_course'] and progress['progress_course'][1],
                    ])
                return response
            except ValidationError:
                return Response("Bad request", status=400)
        return Response(status=403)


class UserGuardView(APIView):
    renderer_classes = (JSONRenderer,)
    permission_classes = (IsAuthenticated,)

    @staticmethod
    def get(request, pk, page):
        try:
            user = get_user_model().objects.get(out_key=pk)
        except get_user_model().DoesNotExist:
            return Response("User doesn't exist", status=404)

        is_i = request.user == user
        res_403 = Response('Permission denied', status=403)
        res_204 = Response(status=204)

        if is_i and not request.user.groups.filter(name='teachers').exists() and page == 'homeworks':
            return res_403

        if is_i and not \
                request.user.groups.filter(name__in=['students', 'managers', 'lead_managers']).exists() \
                and page == 'payment':
            return res_403

        if is_i:
            return res_204

        if page == 'profile' and (request.user.is_superuser or request.user.is_staff):
            return res_204

        return res_403