import datetime
from googleapiclient.discovery import build
from googleapiclient.errors import HttpError

from oauth2client import client
from oauth2client import tools
from oauth2client.file import Storage
from oauth2client.service_account import ServiceAccountCredentials

import httplib2
import os

import argparse

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

class API:
    def __init__(
            self,
            service,
            scopes,
            app_name,
            client_secret_file,
            credentials_dir,
            version = 'v3',
        ):
        self.service_name = service
        self.app_name = app_name
        self.client_secret_file = client_secret_file
        self.credentials_dir = credentials_dir
        self.scopes = scopes
        self._service = None
        self._service_settime = None
        self.version = version
    def get_credentials(self):

        credential_path = os.path.join(self.credentials_dir,
                                       'token.json')

        store = Storage(credential_path)
        credentials = store.get()
        if not credentials or credentials.invalid:
            flow = client.flow_from_clientsecrets(self.client_secret_file, self.scopes)
            flow.user_agent = self.app_name
            if flags:
                credentials = tools.run_flow(flow, store, flags)
            else:
                credentials = tools.run(flow, store)
            print('Storing credentials to ' + credential_path)
        return credentials

    def build_service(self):
        credentials = self.get_credentials()

        http = credentials.authorize(httplib2.Http())

        service = build(self.service_name, self.version, http=http, cache_discovery=False)
        return service

    def _needs_renewal(self):
        now = datetime.datetime.today()
        if self._service_settime:
            return (now - self._service_settime) > datetime.timedelta(seconds = 60**2)
        else:
            return True

    @property
    def service(self):
        if self._needs_renewal():
            service = self.build_service()
            self._service = service
            self._service_settime = datetime.datetime.today()
            return service
        else:
            return self._service