from rest_framework.generics import ListAPIView, RetrieveAPIView, GenericAPIView

from drf_yasg.utils import swagger_auto_schema
from drf_yasg import openapi
from django.shortcuts import get_object_or_404
from rest_framework import status
from rest_framework.response import Response

from apps.course.serializers import (
    LessonSerializer
)
from apps.course.models import Course, Lesson, LessonCompletion
from apps.course.doc import *
from utils.exceptions import AppAPIException 
from rest_framework.permissions import IsAuthenticated



class LessonListView(ListAPIView):
    serializer_class = LessonSerializer
    queryset = Lesson.objects.filter(is_active=True)  

    @swagger_auto_schema(
        operation_description=doc_courses_lesson(),
    )
    def get(self, request, *args, **kwargs):
        return super().get(request, *args, **kwargs)
    
    def get_queryset(self):
        course_slug = self.kwargs.get('slug')
        course = get_object_or_404(Course, slug=course_slug)
        course = Course.objects.filter(slug=course_slug).first()
        if not course:
            raise AppAPIException({"message": "course not found"}, status_code=status.HTTP_404_NOT_FOUND)
        
        return self.queryset.filter(course=course).order_by('priority','id')




class LessonDetailView(RetrieveAPIView):
    serializer_class = LessonSerializer

    def get(self, request, *args, **kwargs):
        lesson_id = self.kwargs.get('id')
        lesson = get_object_or_404(Lesson, id=lesson_id, is_active=True)

        course = lesson.course
        lessons = Lesson.objects.filter(course=course, is_active=True).order_by('priority')

        total_lessons = lessons.count()
        current_lesson_number = list(lessons.values_list('id', flat=True)).index(lesson.id) + 1
        next_lesson = lessons.filter(priority__gt=lesson.priority).order_by('priority').first()
        next_lesson_id = next_lesson.id if next_lesson else None
        previous_lesson = lessons.filter(priority__lt=lesson.priority).order_by('-priority').first()
        previous_lesson_id = previous_lesson.id if previous_lesson else None

        lesson_data = self.get_serializer(lesson).data
        lesson_data['total_lessons'] = total_lessons
        lesson_data['current_lesson_number'] = current_lesson_number
        lesson_data['next_lesson_id'] = next_lesson_id
        lesson_data['previous_lesson_id'] = previous_lesson_id
        lesson_data['can_go_next'] = next_lesson is not None



        
        # # Get the next and previous lessons based on priority and id
        # next_lesson = Lesson.objects.filter(
        #     course=lesson.course,
        #     is_active=True,
        #     priority__gte=lesson.priority,
        #     id__gt=lesson.id
        # ).order_by('priority', 'id').first()

        # previous_lesson = Lesson.objects.filter(
        #     course=lesson.course,
        #     is_active=True,
        #     priority__lte=lesson.priority,
        #     id__lt=lesson.id
        # ).order_by('-priority', '-id').first()
        
        # total_lessons = Lesson.objects.filter(course=lesson.course, is_active=True).count()
        # # Calculate the current lesson number in the course
        # current_lesson_number = Lesson.objects.filter(
        #     course=lesson.course,
        #     is_active=True,
        #     priority__lte=lesson.priority
        # ).count()
        
        # # Serialize the current lesson
        # lesson_data = self.get_serializer(lesson).data
        # # Add current lesson number and total lessons
        # lesson_data['current_lesson_number'] = current_lesson_number
        # lesson_data['total_lessons'] = total_lessons
        
        # # Add next and previous lesson ids
        # lesson_data['next_lesson_id'] = next_lesson.id if next_lesson else None
        # lesson_data['previous_lesson_id'] = previous_lesson.id if previous_lesson else None


        return Response(lesson_data)



class LessonCompletionCreateAPIView(GenericAPIView):
    permission_classes = [IsAuthenticated]


    @swagger_auto_schema(
        request_body=openapi.Schema(
            type=openapi.TYPE_OBJECT,
            required=['lesson_id'],
            properties={
                'lesson_id': openapi.Schema(type=openapi.TYPE_INTEGER, description='ID of the lesson to be marked as completed'),
            },
        ),
        responses={
            201: 'Lesson completed successfully.',
            200: 'Lesson already completed.',
            400: 'Lesson ID is required.',
            404: 'Lesson not found.',
        }
    )
    def post(self, request):
        student = request.user  # Assuming the user is the student
        lesson_id = request.data.get('lesson_id')

        if not lesson_id:
            return Response({'error': 'Lesson ID is required.'}, status=status.HTTP_400_BAD_REQUEST)
        try:
            lesson = Lesson.objects.get(id=lesson_id)
        except Lesson.DoesNotExist:
            return Response({'error': 'Lesson not found.'}, status=status.HTTP_404_NOT_FOUND)

        # Check if the lesson is already completed by the student
        if LessonCompletion.objects.filter(student=student, lesson=lesson).exists():
            return Response({'message': 'Lesson already completed.'}, status=status.HTTP_200_OK)

        # Create a new completion record
        completion = LessonCompletion(student=student, lesson=lesson)
        completion.save()

        return Response({'message': 'Lesson completed successfully.'}, status=status.HTTP_201_CREATED)