import http.client
import json
import os
from time import sleep
from urllib.parse import urlencode


class NotAuthenticated(Exception):
    pass


class Authorization:
    token = ""
    lock = False

    @classmethod
    def __authorize(cls) -> None:
        cls.token = ""

        conn = http.client.HTTPSConnection(os.environ.get("AUTH0_HOST"))

        payload = {
            "client_id": os.environ.get("CLIENT_ID"),
            "client_secret": os.environ.get("CLIENT_SECRET"),
            "audience": os.environ.get("AUDIENCE"),
            "grant_type": os.environ.get("GRANT_TYPE"),
            "username": os.environ.get("USERNAME"),
            "password": os.environ.get("PASSWORD"),
            "realm": os.environ.get("REALM"),
        }

        headers = {"content-type": "application/x-www-form-urlencoded"}
        conn.request("POST", "/oauth/token", urlencode(payload), headers)

        res = conn.getresponse()

        data = res.read()
        data = json.loads(data.decode("utf-8"))

        try:
            cls.token = "{} {}".format(data["token_type"], data["access_token"])
        except KeyError:
            raise NotAuthenticated("Authorization failed")

    @classmethod
    def get_token(cls) -> str:
        while cls.lock:
            sleep(1)

        if not cls.token:
            cls.lock = True
            cls.__authorize()
            cls.lock = False

        return cls.token