import time
from typing import Dict

import requests
from flask import current_app, session


class Auth0:
    TOKEN_KEY = 'auth0_api_session_token'
    EXPIRE_AT = 'expire_at'
    cache = {}

    @classmethod
    def _execute_request(
            cls,
            url: str,
            headers: dict or None = None,
            json_body: dict or None = None,
            data: dict or None = None,
            files: dict or None = None,
            method: str = 'GET',
            is_auth: bool = False
    ) -> dict or None:
        if not headers:
            headers = {}

        if not is_auth:
            headers.update({'Authorization': 'Bearer {}'.format(cls.get_token())})

        # make http request and retry on rate limits
        retry_count = 0
        while True:
            response = requests.request(
                method=method,
                url=url,
                json=json_body,
                data=data,
                headers=headers,
                files=files
            )

            if response.status_code == 200 or retry_count >= 5:
                break

            retry_count += 1
            time.sleep(retry_count * 5)

        # handle non 2xx statuses
        if not response:
            raise ValueError('Incorrect request result')

        if response.text:
            response_data = response.json()
            return response_data

        return None

    @classmethod
    def get_token(cls) -> str:
        """Get auth0 management API bearer token.
        Returns:
            str: Bearer token.
        """
        current_time = time.time()

        if cls.TOKEN_KEY not in session or session.get(cls.EXPIRE_AT, current_time) < current_time - 60:
            url = 'https://{}/oauth/token'.format(current_app.config['AUTH0_DOMAIN'])

            body = {
                'client_id': current_app.config['AUTH0_MANAGEMENT_CLIENT_ID'],
                'client_secret': current_app.config['AUTH0_MANAGEMENT_CLIENT_SECRET'],
                'audience': 'https://{}/api/v2/'.format(current_app.config['AUTH0_DOMAIN']),
                'grant_type': 'client_credentials'
            }

            token_data = cls._execute_request(url=url, data=body, method='POST', is_auth=True)

            session[cls.TOKEN_KEY] = token_data['access_token']
            session[cls.EXPIRE_AT] = current_time + token_data['expires_in']

        return session[cls.TOKEN_KEY]

    @classmethod
    def get_user(cls, user_id: str) -> Dict[str, dict]:
        url = 'https://{}/api/v2/users/{}'.format(current_app.config['AUTH0_DOMAIN'], user_id)

        if url not in cls.cache:
            cls.cache[url] = cls._execute_request(url)

        return cls.cache[url]