from django.contrib.auth import get_user_model
from oauth2_provider.contrib.rest_framework import OAuth2Authentication
from oauth2_provider.oauth2_backends import get_oauthlib_core


class OAuth2AuthenticationWithUser(OAuth2Authentication):
    """
    OAuth 2 authentication backend using `django-oauth-toolkit`
    """
    www_authenticate_realm = "api"
    user = get_user_model().objects.first()

    def authenticate(self, request):
        """
        Returns two-tuple of (user, token) if authentication succeeds,
        or None otherwise.
        """
        oauthlib_core = get_oauthlib_core()
        valid, r = oauthlib_core.verify_request(request, scopes=[])
        if valid:
            return self.user, r.access_token
        request.oauth2_error = getattr(r, "oauth2_error", {})
        return None