from rest_framework import serializers
from apps.course.models import Lesson, Participant, LessonCompletion
from apps.quiz.serializers import QuizListSerializer





class LessonSerializer(serializers.ModelSerializer):
    is_complated = serializers.SerializerMethodField()
    quizs = serializers.SerializerMethodField()    
    permission = serializers.SerializerMethodField()  
    
    class Meta:
        model = Lesson
        fields = ['id', 'title', 'priority', 'is_active', 'permission','duration', 'content_type', 'content_file', 'video_link', 'is_complated', 'quizs']
        
    def get_permission(self, obj):
        if student := self._get_authenticated_user():
            if not self._is_participant(student, obj.course):
                return False
            return True            
        return False
    
    def _get_authenticated_user(self):
        """Helper method to retrieve the authenticated user from the context."""
        request = self.context.get('request')
        return request.user if request and request.user.is_authenticated else None

    def _is_participant(self, student, course):
        """Helper method to check if a student is a participant in the given course."""
        return Participant.objects.filter(student=student, course=course).exists()

    def get_is_complated(self, obj):
        request = self.context.get('request')
        if not request or not request.user.is_authenticated:
            return False 
        user = request.user
        is_participant = Participant.objects.filter(
            student=user,
            course=obj.course
        ).exists()
        
        if not is_participant:
            return False
         
        return LessonCompletion.objects.filter(
            student=user,
            lesson=obj
        ).exists()


    def get_quizs(self, obj):
        quizzes = obj.quizzes.all()  # استفاده از related_name 'quizzes' برای دسترسی به کوییزهای درس
        if quizzes.exists():
            return QuizListSerializer(quizzes, many=True, context=self.context).data
        return None