from rest_framework import serializers
from django.utils.translation import gettext as _

from labs.models import (
    ExamVariant,
)


class ExamAttemptCreateSerializer(serializers.Serializer):
    variant_id = serializers.IntegerField(required=True)

    variant: ExamVariant | None = None

    def validate_variant_id(self, value):
        try:
            self.variant = ExamVariant.objects.select_related("exam").get(
                id=value,
                exam__published=True,
            )
        except ExamVariant.DoesNotExist:
            raise serializers.ValidationError(
                _("The specified exam variant does not exist.")
            )
        return value