from oauth2_provider.contrib.rest_framework import OAuth2Authentication
from oauth2_provider.models import Application
from oauth2_provider.oauth2_backends import get_oauthlib_core


class OAuth2ClientCredentialAuthentication(OAuth2Authentication):

    def authenticate(self, request):
        authentication = super().authenticate(request)

        if authentication is not None and not self.is_client_credential_request(authentication):
            return authentication

        if self.is_client_credential_request(authentication):
            access_token = authentication[1]
            user = access_token.application.user
            return user, access_token

        return None

    def is_client_credential_request(self, authentication):
        access_token = authentication[1]
        return access_token.application.authorization_grant_type == Application.GRANT_CLIENT_CREDENTIALS