from django.contrib import auth
from django.utils.deprecation import MiddlewareMixin
from django.core.exceptions import ImproperlyConfigured

from .settings import sso_settings


class SsoMiddleware(MiddlewareMixin):

    def process_request(self, request):
        if not hasattr(request, 'user'):
            raise ImproperlyConfigured(
                "The Django remote user auth middleware requires the"
                " authentication middleware to be installed.  Edit your"
                " MIDDLEWARE setting to insert"
                " 'django.contrib.auth.middleware.AuthenticationMiddleware'"
                " before the pingcap_cookie_sso.middleware.SsoMiddleware class.")

        try:
            sso_session_id = request.COOKIES[sso_settings.SSO_COOKIE_NAME]
        except KeyError:
            if request.user.is_authenticated:
                auth.logout(request)
            return

        if not request.user.is_authenticated and sso_session_id:
            user = auth.authenticate(request, sso_session_id=sso_session_id)
            if user:
                request.user = user
                auth.login(request, user)
            else:
                request._sso_auth_failed = True