import logging

from data.users.federated import FederatedUsers, UserInformation
from oauth.loginmanager import OAuthLoginManager
from oauth.oidc import PublicKeyLoadException
from util.security.jwtutil import InvalidTokenError


logger = logging.getLogger(__name__)


class UnknownServiceException(Exception):
  pass


class OIDCInternalAuth(FederatedUsers):
  """ Handles authentication by delegating authentication to a signed OIDC JWT produced by the
      configured OIDC service.
  """
  def __init__(self, config, login_service_id, requires_email):
    super(OIDCInternalAuth, self).__init__('oidc', requires_email)
    login_manager = OAuthLoginManager(config)
    self.login_service = login_manager.get_service(login_service_id)
    if self.login_service is None:
      raise UnknownServiceException('Unknown OIDC login service %s' % login_service_id)

  @property
  def supports_encrypted_credentials(self):
    # Since the "password" is already a signed JWT.
    return False

  def get_user(self, username_or_email):
    return (None, 'Cannot retrieve users for OIDC')

  def query_users(self, query, limit=20):
    return (None, 'Cannot query users for OIDC')

  def verify_credentials(self, username_or_email, id_token):
    try:
      payload = self.login_service.decode_user_jwt(id_token)
    except InvalidTokenError as ite:
      logger.exception('Got invalid token error on OIDC decode: %s', ite.message)
      return (None, 'Could not validate OIDC token')
    except PublicKeyLoadException as pke:
      logger.exception('Could not load public key during OIDC decode: %s', pke.message)
      return (None, 'Could not validate OIDC token')

    user_info = UserInformation(username=payload['sub'], id=payload['sub'], email=None)
    return (user_info, None)