import logging

from enum import Enum

from app import authentication
from auth.oauth import validate_oauth_token
from auth.validateresult import ValidateResult, AuthKind
from data import model
from util.names import parse_robot_username

logger = logging.getLogger(__name__)

ACCESS_TOKEN_USERNAME = '$token'
OAUTH_TOKEN_USERNAME = '$oauthtoken'


class CredentialKind(Enum):
  user = 'user'
  robot = 'robot'
  token = ACCESS_TOKEN_USERNAME
  oauth_token = OAUTH_TOKEN_USERNAME


def validate_credentials(auth_username, auth_password_or_token):
  """ Validates a pair of auth username and password/token credentials. """
  # Check for access tokens.
  if auth_username == ACCESS_TOKEN_USERNAME:
    logger.debug('Found basic auth header for access token')
    try:
      token = model.token.load_token_data(auth_password_or_token)
      logger.debug('Successfully validated basic auth for access token %s', token.id)
      return ValidateResult(AuthKind.credentials, token=token), CredentialKind.token
    except model.DataModelException:
      logger.warning('Failed to validate basic auth for access token %s', auth_password_or_token)
      return (ValidateResult(AuthKind.credentials, error_message='Invalid access token'),
              CredentialKind.token)

  # Check for OAuth tokens.
  if auth_username == OAUTH_TOKEN_USERNAME:
    return validate_oauth_token(auth_password_or_token), CredentialKind.oauth_token

  # Check for robots and users.
  is_robot = parse_robot_username(auth_username)
  if is_robot:
    logger.debug('Found basic auth header for robot %s', auth_username)
    try:
      robot = model.user.verify_robot(auth_username, auth_password_or_token)
      logger.debug('Successfully validated basic auth for robot %s', auth_username)
      return ValidateResult(AuthKind.credentials, robot=robot), CredentialKind.robot
    except model.InvalidRobotException as ire:
      logger.warning('Failed to validate basic auth for robot %s: %s', auth_username, ire.message)
      return ValidateResult(AuthKind.credentials, error_message=ire.message), CredentialKind.robot

  # Otherwise, treat as a standard user.
  (authenticated, err) = authentication.verify_and_link_user(auth_username, auth_password_or_token,
                                                             basic_auth=True)
  if authenticated:
    logger.debug('Successfully validated basic auth for user %s', authenticated.username)
    return ValidateResult(AuthKind.credentials, user=authenticated), CredentialKind.user
  else:
    logger.warning('Failed to validate basic auth for user %s: %s', auth_username, err)
    return ValidateResult(AuthKind.credentials, error_message=err), CredentialKind.user