import logging

from oauth.base import OAuthEndpoint
from oauth.login import OAuthLoginService, OAuthLoginException
from util import slash_join

logger = logging.getLogger(__name__)

class GithubOAuthService(OAuthLoginService):
  def __init__(self, config, key_name):
    super(GithubOAuthService, self).__init__(config, key_name)

  def login_enabled(self, config):
    return config.get('FEATURE_GITHUB_LOGIN', False)

  def service_id(self):
    return 'github'

  def service_name(self):
    if self.is_enterprise():
      return 'GitHub Enterprise'

    return 'GitHub'

  def get_icon(self):
    return 'fa-github'

  def get_login_scopes(self):
    if self.config.get('ORG_RESTRICT'):
      return ['user:email', 'read:org']

    return ['user:email']

  def allowed_organizations(self):
    if not self.config.get('ORG_RESTRICT', False):
      return None

    allowed = self.config.get('ALLOWED_ORGANIZATIONS', None)
    if allowed is None:
      return None

    return [org.lower() for org in allowed]

  def get_public_url(self, suffix):
    return slash_join(self._endpoint(), suffix)

  def _endpoint(self):
    return self.config.get('GITHUB_ENDPOINT', 'https://github.com')

  def is_enterprise(self):
    return self._api_endpoint().find('.github.com') < 0

  def authorize_endpoint(self):
    return OAuthEndpoint(slash_join(self._endpoint(), '/login/oauth/authorize'))

  def token_endpoint(self):
    return OAuthEndpoint(slash_join(self._endpoint(), '/login/oauth/access_token'))

  def user_endpoint(self):
    return OAuthEndpoint(slash_join(self._api_endpoint(), 'user'))

  def _api_endpoint(self):
    return self.config.get('API_ENDPOINT', slash_join(self._endpoint(), '/api/v3/'))

  def api_endpoint(self):
    endpoint = self._api_endpoint()
    if endpoint.endswith('/'):
      return endpoint[0:-1]

    return endpoint

  def email_endpoint(self):
    return slash_join(self._api_endpoint(), 'user/emails')

  def orgs_endpoint(self):
    return slash_join(self._api_endpoint(), 'user/orgs')

  def validate_client_id_and_secret(self, http_client, app_config):
    # First: Verify that the github endpoint is actually Github by checking for the
    # X-GitHub-Request-Id here.
    api_endpoint = self._api_endpoint()
    result = http_client.get(api_endpoint, auth=(self.client_id(), self.client_secret()), timeout=5)
    if not 'X-GitHub-Request-Id' in result.headers:
      raise Exception('Endpoint is not a Github (Enterprise) installation')

    # Next: Verify the client ID and secret.
    # Note: The following code is a hack until such time as Github officially adds an API endpoint
    # for verifying a {client_id, client_secret} pair. That being said, this hack was given to us
    # *by a Github Engineer*, so I think it is okay for the time being :)
    #
    # TODO(jschorr): Replace with the real API call once added.
    #
    # Hitting the endpoint applications/{client_id}/tokens/foo will result in the following
    # behavior IF the client_id is given as the HTTP username and the client_secret as the HTTP
    # password:
    #   - If the {client_id, client_secret} pair is invalid in some way, we get a 401 error.
    #   - If the pair is valid, then we get a 404 because the 'foo' token does not exists.
    validate_endpoint = slash_join(api_endpoint, 'applications/%s/tokens/foo' % self.client_id())
    result = http_client.get(validate_endpoint, auth=(self.client_id(), self.client_secret()),
                             timeout=5)
    return result.status_code == 404

  def validate_organization(self, organization_id, http_client):
    org_endpoint = slash_join(self._api_endpoint(), 'orgs/%s' % organization_id.lower())

    result = http_client.get(org_endpoint,
                             headers={'Accept': 'application/vnd.github.moondragon+json'},
                             timeout=5)

    return result.status_code == 200


  def get_public_config(self):
    return  {
      'CLIENT_ID': self.client_id(),
      'AUTHORIZE_ENDPOINT': self.authorize_endpoint().to_url(),
      'GITHUB_ENDPOINT': self._endpoint(),
      'ORG_RESTRICT': self.config.get('ORG_RESTRICT', False)
    }

  def get_login_service_id(self, user_info):
    return user_info['id']

  def get_login_service_username(self, user_info):
    return user_info['login']

  def get_verified_user_email(self, app_config, http_client, token, user_info):
    v3_media_type = {
      'Accept': 'application/vnd.github.v3'
    }

    token_param = {
      'access_token': token,
    }

    # Find the e-mail address for the user: we will accept any email, but we prefer the primary
    get_email = http_client.get(self.email_endpoint(), params=token_param, headers=v3_media_type)
    if get_email.status_code // 100 != 2:
      raise OAuthLoginException('Got non-2XX status code for emails endpoint: %s' %
                                get_email.status_code)

    verified_emails = [email for email in get_email.json() if email['verified']]
    primary_emails = [email for email in get_email.json() if email['primary']]

    # Special case: We don't care about whether an e-mail address is "verified" under GHE.
    if self.is_enterprise() and not verified_emails:
      verified_emails = primary_emails

    allowed_emails = (primary_emails or verified_emails or [])
    return allowed_emails[0]['email'] if len(allowed_emails) > 0 else None

  def service_verify_user_info_for_login(self, app_config, http_client, token, user_info):
    # Retrieve the user's orgnizations (if organization filtering is turned on)
    if self.allowed_organizations() is None:
      return

    moondragon_media_type = {
      'Accept': 'application/vnd.github.moondragon+json'
    }

    token_param = {
      'access_token': token,
    }

    get_orgs = http_client.get(self.orgs_endpoint(), params=token_param,
                               headers=moondragon_media_type)

    if get_orgs.status_code // 100 != 2:
      logger.debug('get_orgs response: %s', get_orgs.json())
      raise OAuthLoginException('Got non-2XX response for org lookup: %s' %
                                get_orgs.status_code)

    organizations = set([org.get('login').lower() for org in get_orgs.json()])
    matching_organizations = organizations & set(self.allowed_organizations())
    if not matching_organizations:
      logger.debug('Found organizations %s, but expected one of %s', organizations,
                   self.allowed_organizations())
      err = """You are not a member of an allowed GitHub organization.
               Please contact your system administrator if you believe this is in error."""
      raise OAuthLoginException(err)