import requests
from typing import Type

from flask import g


class ClientFactory:
    """Ext API class factory.

    """

    def _get_instance(self, prop_name: str, instance_cls: Type, *args, **kwargs):
        """Get some object from g or create new.

        Args:
            prop_name: G property name.
            instance_cls: Class to create instance for.

        """
        instance = getattr(g, prop_name, None)
        if not instance:
            instance = instance_cls(*args, **kwargs)
            setattr(g, prop_name, instance)
        return instance

    def _get_session(self):
        """Get session from g or create new.

        """
        return self._get_instance("requests_session", requests.Session)

    def _get_client(self, client_cls: Type):
        """Get client from g or create new.

        """
        client_prop_name = f"{client_cls.__name__.lower()}_client"
        return self._get_instance(client_prop_name, client_cls, self._get_session())


clients = ClientFactory()