from rest_framework import serializers

from apps.course.access import user_has_course_access
from apps.quiz.models import QuizParticipant, ParticipantAnswer


class ParticipantAnswerSerializer(serializers.ModelSerializer):
    class Meta:
        model = ParticipantAnswer
        fields = ['question', 'option_num', 'at_time', 'answer_timing']



class QuizParticipantSerializer(serializers.ModelSerializer):
    user = serializers.HiddenField(default=serializers.CurrentUserDefault())
    answers = ParticipantAnswerSerializer(many=True)

    def validate_quiz(self, obj):
        if QuizParticipant.objects.filter(quiz=obj, user=self.context['request'].user).exists():
            raise serializers.ValidationError('you have already participated in the quiz')

        course = getattr(obj, 'course', None)
        if course and not user_has_course_access(self.context['request'].user, course):
            raise serializers.ValidationError('you do not have access to this quiz')

        return obj

    class Meta:
        model = QuizParticipant
        fields = [
            'quiz', 'user', 'started_at', 'ended_at', 'total_timing',
            'question_score', 'timing_score', 'total_score',
            'answers',
        ]

    def create(self, validated_data):
        answers = validated_data.pop('answers', [])
        
        quiz = validated_data.get('quiz')
        total_questions = quiz.questions.count()
        correct_count = 0
        questions_map = {q.id: q.correct_answer for q in quiz.questions.all()}
        
        for ans in answers:
            # Depending on if ans['question'] is an instance or ID
            q_id = ans.get('question').id if hasattr(ans.get('question'), 'id') else ans.get('question')
            option_num = ans.get('option_num')
            if q_id in questions_map and questions_map[q_id] == option_num:
                correct_count += 1
                
        question_score = round((correct_count / total_questions) * 100) if total_questions > 0 else 0
        
        validated_data['question_score'] = question_score
        validated_data['timing_score'] = 0
        validated_data['total_score'] = question_score
        
        obj = super().create(validated_data)
        answers_objs = []
        for ans in answers:
            answers_objs.append(
                ParticipantAnswer(
                    participant=obj,
                    **ans,
                )
            )

        ParticipantAnswer.objects.bulk_create(answers_objs)

        return obj