from django.utils import timezone
from rest_framework.permissions import IsAuthenticated
from rest_framework.response import Response
from rest_framework.views import APIView

from apps.common.api.base_viewset import BaseModelViewSet
from apps.common.api.permissions import IsStaffOrReadOnly
from apps.courses.models import Course, Enrollment, Lesson, LessonProgress
from apps.courses.serializers import CourseSerializer, EnrollCourseResponseSerializer, MyCourseSerializer, \
    CompleteLessonResponseSerializer


class CourseViewSet(BaseModelViewSet):
    queryset = Course.objects.all()
    serializer_class = CourseSerializer
    permission_classes = [IsStaffOrReadOnly]

    search_fields = ('title', 'description')
    filterset_fields = ['published']
    ordering = ['-created_at']

class EnrollCourseView(APIView):
    permission_classes = [IsAuthenticated]

    def post(self, request, course_id):
        course = Course.objects.get(id=course_id)
        enrollment, created = Enrollment.objects.get_or_create(user=request.user, course=course)
        serializer = EnrollCourseResponseSerializer({
            'course_id' : course.id,
            'enrolled_at' : enrollment.enrolled_at,
        })

        return Response(serializer.data)

class MyCoursesView(APIView):
    permission_classes = [IsAuthenticated]

    def get(self, request):
        enrollments = Enrollment.objects.filter(user=request.user)

        data = [
            {
                'course_id': e.course.id,
                'title': e.course.title,
                'enrolled_at': e.enrolled_at,
           } for e in enrollments
        ]

        serializer = MyCourseSerializer(data, many=True)
        return Response(serializer.data)

class CompleteLessonView(APIView):
    permission_classes = [IsAuthenticated]

    def post(self, request, lesson_id):
        lesson = Lesson.objects.get(id=lesson_id)

        progress, _ = LessonProgress.objects.get_or_create(
            user=request.user,
            lesson=lesson
        )

        progress.completed = True
        progress.complete_at = timezone.now()
        progress.save()

        serializer = CompleteLessonResponseSerializer({
            'lesson_id' : lesson.id,
            'completed' : progress.completed,
            'completed_at' : progress.complete_at,
        })

        return Response(serializer.data)