import datetime
import json
from http import HTTPStatus
from urllib import request
from urllib.parse import urlencode
from urllib.error import HTTPError

class ZohoToken:
    def __init__(self, client_id, client_secret, refresh_token):
        self.client_id = client_id
        self.client_secret = client_secret
        self.refresh_token = refresh_token
        self._access_token = None
        self.expires_at = None

    def update_token(self):
        url = "https://accounts.zoho.com/oauth/v2/token?%s" % urlencode({
            "refresh_token": self.refresh_token,
            "client_id": self.client_id,
            "client_secret": self.client_secret,
            "grant_type": "refresh_token",
        })
        req = request.Request(url, method="POST")
        with request.urlopen(req) as f:
            data = json.loads(f.read().decode())
            self._access_token = data["access_token"]
            self.expires_at = datetime.datetime.now() + datetime.timedelta(seconds=int(data["expires_in"]))

    def get_token(self):
        if self._access_token is None or self.expires_at <= datetime.datetime.now():
            self.update_token()
        return self._access_token

def authenticate(token, key):
    url = "https://www.zohoapis.com/crm/v2/Contacts/search?%s" % urlencode({
        "criteria": "(Key_ID:equals:%s)" % key,
    })
    req = request.Request(url, method="GET", headers={
        "Authorization": "Zoho-oauthtoken %s" % token.get_token(),
    })
    print("Pinging server with key: %s (%s)" % (key, url))
    try:
        with request.urlopen(req) as response:
            return response.status == HTTPStatus.OK
    except HTTPError as e:
        print("Error pinging server: %s" % e)

    return False