import base64

import os
from jwt import DecodeError
from rest_framework.parsers import MultiPartParser

from courses.models import Course, Lesson, Topic, upload_material
from rest_framework.renderers import JSONRenderer, BrowsableAPIRenderer
from rest_framework.response import Response
from rest_framework.views import APIView
from django.core.files.storage import default_storage
from django.core.files.base import ContentFile

from courses.serializers import CourseDetailSerializer, CourseTreeSerializer, LessonSerializer, TeacherLessonSerializer
import jwt

from courses.tasks import add_lesson
from lms import settings


class TreeView(APIView):
    renderer_classes = (JSONRenderer,)
    status_code = 200

    def get(self, request, slug):

        try:
            course = Course.objects.get(slug=slug)
            return Response(CourseTreeSerializer(course).data, self.status_code)
        except Course.DoesNotExist:
            return Response("Course doesn't exist", status=404)


class CourseListView(APIView):
    renderer_classes = (JSONRenderer,)
    status_code = 200

    def post(self, request):
        course = Course.objects.update_or_create_course(**request.JSON.dict())
        return Response(CourseDetailSerializer(course).data, status=self.status_code)

    def get(self, request):
        """
        This API endpoint return list of courses.
        ---
        """
        res = [CourseDetailSerializer(course).data for course in Course.objects.all()]
        return Response(res, self.status_code)


class CourseDetailView(APIView):
    renderer_classes = (JSONRenderer,)
    status_code = 200

    @staticmethod
    def delete(request, slug):
        try:
            Course.objects.get(slug=slug).delete()
        except Course.DoesNotExist:
            return Response("Курса не существует", status=404)
        return Response(status=204)

    def get(self, request, slug):
        return Response(CourseDetailSerializer(Course.objects.get(slug=slug)).data, self.status_code)


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

    @staticmethod
    def delete(request, topic_id):
        if request.user and request.user.is_staff:
            try:
                t = Topic.objects.get(id=topic_id)
            except Topic.DoesNotExist:
                return Response("Темы не существует", status=404)
            t.delete()
            return Response(CourseTreeSerializer(t.course).data, status=200)


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

    @staticmethod
    def delete(request, lesson_token):
        if request.user and request.user.is_staff:
            try:
                l = Lesson.objects.get(token=lesson_token)
            except Lesson.DoesNotExist:
                return Response("Темы не существует", status=404)
            l.delete()
            return Response(CourseTreeSerializer(l.topic.course).data, status=200)


class UpdateLessonView(APIView):
    renderer_classes = (JSONRenderer, BrowsableAPIRenderer)
    parser_classes = (MultiPartParser,)

    @staticmethod
    def bool_transformer(val):
        if val == 'false':
            return False
        if val == 'true':
            return True
        return val

    def post(self, request):
        lesson_token = request.POST.get('token', None)
        sort = request.POST.get('sort', None)
        topic_id = request.POST.get('topic', None)
        title = request.POST.get('title', None)
        description = request.POST.get('description', None)
        video = request.POST.get('video', None)
        materials_url = request.POST.get('materials_url', '')
        free = self.bool_transformer(request.POST.get('free', None))
        is_hm = self.bool_transformer(request.POST.get('is_hm', None))

        if topic_id is None:
            return Response("topic не передан", status=400)

        if sort is None:
            return Response("sort не передан", status=400)

        try:
            topic = Topic.objects.get(id=topic_id)
        except Topic.DoesNotExist:
            return Response("Тема не найдена", status=404)

        if lesson_token is None:
            if title is None:
                return Response("Название урока не переданно", status=400)
            for lesson in reversed(topic.lesson_set.filter(sort__gte=sort)):
                lesson.sort = lesson.sort + 1
                lesson.save()
            l = Lesson.objects.create(
                title=title,
                topic=topic,
                sort=sort,
            )
        else:
            try:
                l = Lesson.objects.get(token=lesson_token)
            except Lesson.DoesNotExist:
                return Response("Урок не найден", status=404)

        l.title = l.title if title is None else title
        l.video = l.video if video is None else video
        l.free = l.free if free is None else free
        l.is_hm = l.is_hm if is_hm is None else is_hm
        l.description = l.description if description is None else description
        if not l.sort == sort:
            for lesson in reversed(topic.lesson_set.filter(sort__gte=sort)):
                lesson.sort = lesson.sort + 1
                lesson.save()
            l.sort = sort

        materials = list(l.materials)
        if not materials_url == '':
            materials = base64.b64decode(materials_url).decode("utf-8").split(',')
        for key in request.FILES:
            f = request.FILES[key]
            path = default_storage.save(upload_material(l, f.name), ContentFile(f.read()))
            materials.append(path)

        l.materials = materials
        l.save()

        return Response(CourseTreeSerializer(topic.course).data, status=200)


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

    @staticmethod
    def post(request):
        topic_id = request.JSON.get('id', None)
        sort = request.JSON.get('sort', None)
        course_token = request.JSON.get('course_token', None)
        title = request.JSON.get('title', None)

        if course_token is None:
            return Response("Не передан course_token", status=400)

        if sort is None:
            return Response("Не передан sort", status=400)

        try:
            course = Course.objects.get(token=course_token)
        except Course.DoesNotExist:
            return Response("Курс не найден", status=404)

        try:
            if topic_id:
                t = Topic.objects.get(id=topic_id)
                if not t.sort == sort:
                    for topic in reversed(course.topic_set.filter(sort__gte=sort)):
                        topic.sort = topic.sort + 1
                        topic.save()
                    t.sort = sort
                t.title = t.title if title is None else title
                t.save()
            else:
                raise Topic.DoesNotExist()

        except Topic.DoesNotExist:
            if title is None:
                return Response("Не передан title", status=400)

            for topic in reversed(course.topic_set.filter(sort__gte=sort)):
                topic.sort = topic.sort + 1
                topic.save()

            Topic.objects.create(
                course=course,
                title=title,
                sort=sort,
            )
        return Response(CourseTreeSerializer(course).data, status=200)


class LessonInfoView(APIView):
    renderer_classes = (JSONRenderer,)
    status_code = 200

    def get(self, request, token):
        try:
            lesson = Lesson.objects.get(token=token)
        except Lesson.DoesNotExist:
            return Response('Урок не найден', status=404)
        if request.user.is_authenticated:
            return Response(TeacherLessonSerializer(lesson).data, self.status_code)
        return Response("Пользователь не является преподователем по курсу", status=403)


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

    @staticmethod
    def post(request, token):
        jwt_token = request.JSON.get('jwt_token', None)

        try:
            lesson = Lesson.objects.get(token=token)
        except Lesson.DoesNotExist:
            return Response("Урока не существует", status=404)

        l = LessonSerializer(lesson).data

        try:
            payload = None if jwt_token is None \
                else jwt.decode(jwt_token, settings.COURSE_PROGRESS_SECRET_KEY, algorithms=['HS256'])
        except DecodeError:
            payload = None

        course = lesson.topic.course

        if payload is None:
            if not (lesson.free or request.user.is_authenticated and request.user.is_staff):
                return Response("Bad token", status=400)

            else:
                return Response(l, status=200)

        prev_lesson = course.get_previous(lesson, (lambda x: not x.is_hm) if payload['only_watch'] else None)
        next_lesson = course.get_next(lesson, (lambda x: not x.is_hm) if payload['only_watch'] else None)

        if not prev_lesson is None:
            l['prev_token'] = prev_lesson.token

        if not next_lesson is None:
            l['next_token'] = next_lesson.token

        new_lesson = False
        for payload_lesson in payload['lessons']:
            if payload_lesson['lesson_token'] == str(lesson.token):
                return Response(l, status=200)

            if not prev_lesson is None and str(prev_lesson.token) == payload_lesson['lesson_token']:
                new_lesson = True if prev_lesson is None else \
                    (payload_lesson['status'] == "done" or payload_lesson['status'] == "wait")

        if not new_lesson:
            return Response("Permission denied", status=403)

        # TODO Задача для селери
        add_lesson(request.user.out_key, course.token, lesson.token, lesson.is_hm)

        return Response(l, status=200)