from importlib import import_module

from django.conf import settings

from allauth.headless import app_settings
from allauth.headless.constants import Client


def session_store(session_key=None):
    engine = import_module(settings.SESSION_ENGINE)
    return engine.SessionStore(session_key=session_key)


def new_session():
    return session_store()


def expose_session_token(request):
    if request.allauth.headless.client != Client.APP:
        return
    strategy = app_settings.TOKEN_STRATEGY
    hdr_token = strategy.get_session_token(request)
    modified = request.session.modified
    empty = request.session.is_empty()
    if modified and not empty:
        new_token = strategy.create_session_token(request)
        if not hdr_token or hdr_token != new_token:
            return new_token