import base64
import datetime
import requests
import sys


client_id = '4539b00212a441c6a3716e67e4cb9ef7'
client_secret = '17d34e38d6b14f83a2e86f0d9c8b8780'
expires = datetime.datetime.now().timestamp()
access_token = None


def has_expired():
    return (not access_token) or \
        expires < (datetime.datetime.now().timestamp())


def get_access_token():
    if has_expired():
        client_credentials = \
            bytes(client_id + ':' + client_secret, encoding='utf-8')
        base = base64.b64encode(client_credentials)
        payload = {'grant_type': 'client_credentials'}
        headers = {'Authorization': 'Basic {}'.format(base.decode('utf-8'))}
        r = requests.post('https://accounts.spotify.com/api/token', data=payload,
                          headers=headers)
        json_response = r.json()

        setattr(sys.modules[__name__], 'expires', json_response.get('expires_in', 0) + datetime.datetime.now().timestamp() - 5)
        setattr(sys.modules[__name__], 'access_token', json_response['access_token'])

    return access_token