#!/usr/bin/env python3
import argparse
import os

from oauth2client import client, tools
from oauth2client.file import Storage

flags = argparse.ArgumentParser(parents=[tools.argparser]).parse_args()

# If modifying these scopes, delete your previously saved credentials
# at zulip/bots/gcal/
# NOTE: When adding more scopes, add them after the previous one in the same field, with a space
# seperating them.
SCOPES = "https://www.googleapis.com/auth/calendar.readonly"
# This file contains the information that google uses to figure out which application is requesting
# this client's data.
CLIENT_SECRET_FILE = "client_secret.json"  # noqa: S105
APPLICATION_NAME = "Zulip Calendar Bot"
HOME_DIR = os.path.expanduser("~")


def get_credentials() -> client.Credentials:
    """Gets valid user credentials from storage.

    If nothing has been stored, or if the stored credentials are invalid,
    the OAuth2 flow is completed to obtain the new credentials.

    Returns:
        Credentials, the obtained credential.
    """

    credential_path = os.path.join(HOME_DIR, "google-credentials.json")

    store = Storage(credential_path)
    credentials = store.get()
    if not credentials or credentials.invalid:
        flow = client.flow_from_clientsecrets(os.path.join(HOME_DIR, CLIENT_SECRET_FILE), SCOPES)
        flow.user_agent = APPLICATION_NAME
        # This attempts to open an authorization page in the default web browser, and asks the user
        # to grant the bot access to their data. If the user grants permission, the run_flow()
        # function returns new credentials.
        credentials = tools.run_flow(flow, store, flags)
        print("Storing credentials to " + credential_path)


get_credentials()