import urllib.parse

from django.utils.translation import gettext as _

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

from university.api.base import Endpoint
from university.api.bases.course import CourseEndpoint
from university.api.bases.chapter import ChapterEndpoint
from university.api.bases.lesson import LessonEndpoint
from university.models import Lesson, Question
from university.user_behavior_track import report_event


class AllRecommendEndpoint(Endpoint):

    permission_classes = (AllowAny, )

    def get(self, request, *args, **kwargs):
        datas = []
        recommend_lessons_id = [1, 2, 45]
        for lesson in Lesson.objects.select_related(
                'chapter', 'chapter__course', 'cover_image')\
                .filter(id__in=recommend_lessons_id)[:6]:
            chapter = lesson.chapter
            course = chapter.course
            datas.append({
                'title': lesson.title,
                'short_title': lesson.short_title,
                'slug': lesson.slug,
                'description': lesson.description,
                'speaker': lesson.speaker,
                'periods': lesson.periods,
                'cover_url': lesson.cover_image.url if lesson.cover_image else None,
                'types': lesson.types,
                'course': {
                    'slug': course.slug,
                    'title': course.title,
                    'description': course.description,
                    'cover_url': course.cover_image.url,
                    'license': course.license
                },
                'chapter': {
                    'title': chapter.title,
                    'slug': chapter.slug,
                    'description': chapter.description
                }
            })
        return Response({'detail': _('success'), 'datas': datas})


class CourseRecommendEndpoint(CourseEndpoint):

    permission_classes = (AllowAny, )

    def get(self, request, *args, **kwargs):
        course = kwargs['course']
        datas = []
        recommend_lessons_id = []
        if course.slug == 'PCTA':
            recommend_lessons_id = [3, 4, 11]
        elif course.slug == 'PCTP':
            recommend_lessons_id = [5, 6, 7]
        for lesson in Lesson.objects.select_related('chapter', 'cover_image')\
                .filter(id__in=recommend_lessons_id, cover_image__isnull=False)[:3]:
            chapter = lesson.chapter
            datas.append({
                'title': lesson.title,
                'short_title': lesson.short_title,
                'slug': lesson.slug,
                'description': lesson.description,
                'speaker': lesson.speaker,
                'periods': lesson.periods,
                'cover_url': lesson.cover_image.url if lesson.cover_image else None,
                'types': lesson.types,
                'course': {
                    'slug': course.slug,
                    'title': course.title,
                    'description': course.description,
                    'cover_url': course.cover_image.url,
                    'license': course.license
                },
                'chapter': {
                    'title': chapter.title,
                    'slug': chapter.slug,
                    'description': chapter.description
                }
            })
        return Response({'detail': _('success'), 'datas': datas})


class ChapterLessonListEndpoint(ChapterEndpoint):

    permission_classes = (AllowAny, )

    def get(self, request, *args, **kwargs):
        chapter = kwargs['chapter']
        datas = []
        has_course = request.user.has_course(chapter.course)
        for lesson in chapter.lesson_set.all().order_by('sequence'):
            datas.append({
                'title': lesson.title,
                'short_title': lesson.short_title,
                'slug': lesson.slug,
                'description': lesson.description,
                'speaker': lesson.speaker,
                'periods': lesson.periods,
                'cover_url': lesson.cover_image.url if lesson.cover_image else None,
                'types': lesson.types,
                # For reduce request to database, do not use `has_lesson`
                'has_permission': has_course or lesson.is_free
            })
        return Response({'detail': _('success'), 'datas': datas})


class LessonDetailEndpoint(LessonEndpoint):

    permission_classes = (AllowAny, )

    def get(self, request, lesson, chapter, course, *args, **kwargs):
        datas = {
            'title': lesson.title,
            'short_title': lesson.short_title,
            'slug': lesson.slug,
            'description': lesson.description,
            'objectives': lesson.objectives,
            'key_points': lesson.key_points,
            'speaker': lesson.speaker,
            'periods': lesson.periods,
            'cover_url': lesson.cover_image.url if lesson.cover_image else None,
            'types': lesson.types,
            'is_authenticated': True if request.user.is_authenticated else False,
            'has_permission': False,
            'syllabus': None,
            'quiz': None
        }

        if request.user.has_lesson(lesson):
            if request.user.is_authenticated:
                report_event(
                    request.user,
                    'pu.view_lesson',
                    {
                        'lesson_id': lesson.id,
                        'lesson_slug': lesson.slug,
                        'lesson_title': lesson.title,
                        'chapter_id': chapter.id,
                        'chapter_slug': chapter.slug,
                        'course_id': course.id,
                        'course_slug': course.slug
                    },
                    request,
                    '学习了课程 [{lesson_title}]({lesson_url})'.format(
                        lesson_title=lesson.title,
                        lesson_url='https://university.pingcap.com/courses/{}/chapter/{}/lesson/{}'.format(
                            urllib.parse.quote(course.slug),
                            urllib.parse.quote(chapter.slug),
                            urllib.parse.quote(lesson.slug)))
                )

            # Mark lesson as read when user access lesson details
            request.user.mark_lesson_as_read(lesson)
            if lesson.has_quiz():
                questions, is_passed = lesson.get_quiz(request.user)
                quiz = {
                    'questions': questions,
                    'is_passed': is_passed
                }
            else:
                quiz = None
            datas.update({
                'has_permission': True,
                'syllabus': lesson.get_syllabus(request.user),
                'quiz': quiz
            })

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


class QuizEndpint(LessonEndpoint):

    permission_classes = (IsAuthenticated, )

    def post(self, request, lesson, chapter, course, *args, **kwargs):
        if not request.user.has_lesson(lesson):
            raise PermissionDenied

        if not lesson.has_quiz():
            raise NotFound

        try:
            data = dict()
            for question in lesson.quiz.questions.all():
                question_id = str(question.id)
                data[question_id] = request.data['answers'][question_id] == question.answer
            user_quiz, is_created = request.user.userquiz_set.get_or_create(
                quiz=lesson.quiz, lesson=lesson, chapter=chapter, course=course)
            user_quiz.answer = request.data['answers']
            user_quiz.is_passed = all(data.values())
            user_quiz.save()

            report_event(
                request.user,
                'pu.submit_quiz',
                {
                    'lesson_id': lesson.id,
                    'lesson_slug': lesson.slug,
                    'lesson_title': lesson.title,
                    'quiz_id': lesson.quiz.id,
                    'is_passed': user_quiz.is_passed
                },
                request,
                '在课程 {lesson_title} 提交了课后练习题, 结果: {result}'.format(
                    lesson_title=lesson.title,
                    result='通过' if user_quiz.is_passed else '未通过'
                )
            )

            return Response({
                'detail': _('success'),
                'datas': data
            })
        except Exception:
            return Response({
                'detail': _('params error')
            }, status=400)


class QuizHintEndpint(LessonEndpoint):

    permission_classes = (IsAuthenticated, )

    def get(self, request, lesson, *args, **kwargs):
        if not request.user.has_lesson(lesson):
            raise PermissionDenied

        if not lesson.has_quiz():
            raise NotFound

        try:
            hint = lesson.quiz.questions.get(pk=kwargs['question_id']).hint
            return Response({
                'detail': _('success'),
                'datas': {
                    'hint': hint
                }
            })
        except Question.DoesNotExist:
            raise NotFound