from authlib.integrations.requests_client import OAuth2Session, OAuthError
from authlib.oauth2.rfc6749 import OAuth2Token
from flask import jsonify, request

from slz_api_service.auth import AuthCredentials
from slz_api_service.errors import AuthError, Codes


class OAuth2:

    @staticmethod
    def post():
        """Endpoint: ``POST /v1/oauth/token``"""
        params = request.json

        # pass thru credentials from request to Auth0 to get a token
        credentials = AuthCredentials.from_dict(params)
        session = OAuth2Session(client_id=credentials.client_id,
                                client_secret=credentials.client_secret,
                                scope=credentials.scope,
                                token_endpoint_auth_method=credentials.token_endpoint_auth_method)
        try:
            token: OAuth2Token = session.fetch_access_token(credentials.access_token_url,
                                                            grant_type=credentials.grant_type,
                                                            audience=credentials.audience)
        except OAuthError:
            raise AuthError({
                'code': Codes.unauthorized.value,
                'description': 'Unauthorized credentials provided',
            })
        return jsonify(token)