import logging

from datetime import datetime

from auth.scopes import scopes_from_scope_string
from auth.validateresult import AuthKind, ValidateResult
from data import model

logger = logging.getLogger(__name__)

def validate_bearer_auth(auth_header):
  """ Validates an OAuth token found inside a basic auth `Bearer` token, returning whether it
      points to a valid OAuth token.
  """
  if not auth_header:
    return ValidateResult(AuthKind.oauth, missing=True)

  normalized = [part.strip() for part in auth_header.split(' ') if part]
  if normalized[0].lower() != 'bearer' or len(normalized) != 2:
    logger.debug('Got invalid bearer token format: %s', auth_header)
    return ValidateResult(AuthKind.oauth, missing=True)

  (_, oauth_token) = normalized
  return validate_oauth_token(oauth_token)


def validate_oauth_token(token):
  """ Validates the specified OAuth token, returning whether it points to a valid OAuth token.
  """
  validated = model.oauth.validate_access_token(token)
  if not validated:
    logger.warning('OAuth access token could not be validated: %s', token)
    return ValidateResult(AuthKind.oauth,
                          error_message='OAuth access token could not be validated')

  if validated.expires_at <= datetime.utcnow():
    logger.warning('OAuth access with an expired token: %s', token)
    return ValidateResult(AuthKind.oauth, error_message='OAuth access token has expired')

  # Don't allow disabled users to login.
  if not validated.authorized_user.enabled:
    return ValidateResult(AuthKind.oauth,
                          error_message='Granter of the oauth access token is disabled')

  # We have a valid token
  scope_set = scopes_from_scope_string(validated.scope)
  logger.debug('Successfully validated oauth access token: %s with scope: %s', token,
               scope_set)
  return ValidateResult(AuthKind.oauth, oauthtoken=validated)