sharix-open-tickets/api/v2/serializers/tickets.py

from rest_framework import serializers
from tickets.models import Ticket

class TicketSerializer(serializers.ModelSerializer):
    available_statuses = serializers.SerializerMethodField()

    def get_available_statuses(self, obj):
        return obj.get_available_statuses()

    def validate_status(self, status):
        valid_statuses = self.get_available_statuses(self.instance)
        if not valid_statuses or status not in valid_statuses:
            raise serializers.ValidationError("Invalid value for the status field")
        return status

    class Meta():
        model = Ticket
        fields = "__all__"
        ref_name = "TicketSerializer_v2"