from django.db import models
from django.forms.models import model_to_dict


class SecondDbManager(models.Manager):
    def get_queryset(self):
        qs = super().get_queryset()

        # if `use_db` is set on model use that for choosing the DB
        if hasattr(self.model, 'use_db'):
            qs = qs.using(self.model.use_db)

        return qs


class MigrateMixin(models.Model):
    """Mixin to data transfer from legacy database"""
    use_db = 'legacy'
    objects = SecondDbManager()

    def _parse_instance_fields(self, fields):
        model_dict = model_to_dict(self, fields)
        print(getattr(self, "using", "Using not found"))

    class Meta:
        abstract = True