import datetime
import os
import pickle


from googleapiclient.discovery import build
from google_auth_oauthlib.flow import InstalledAppFlow
from google.auth.transport.requests import Request

import gapi


HOUR = datetime.timedelta(seconds=60 ** 2)


class API:
    def __init__(
        self,
        service,
        scopes,
        app_name,
        client_secret_file=os.path.join(gapi.state_dir, "client_secret.json"),
        credentials_dir=gapi.state_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):
        creds = None
        # The file token.pickle stores the user's access and refresh tokens, and is
        # created automatically when the authorization flow completes for the first
        # time.
        credential_path = os.path.join(self.credentials_dir, "token.pickle")
        if os.path.exists(credential_path):
            with open(credential_path, "rb") as token:
                creds = pickle.load(token)
        # If there are no (valid) credentials available, let the user log in.
        if not creds or not creds.valid:
            if creds and creds.expired and creds.refresh_token:
                creds.refresh(Request())
            else:
                flow = InstalledAppFlow.from_client_secrets_file(
                    self.client_secret_file, self.scopes
                )
                creds = flow.run_local_server(port=0)
            # Save the credentials for the next run
            print("Storing credentials to " + credential_path)
            with open(credential_path, "wb") as token:
                pickle.dump(creds, token)
        return creds

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

        service = build(self.service_name, self.version, credentials=credentials)
        return service

    def _needs_renewal(self):
        now = datetime.datetime.today()
        if self._service_settime:
            return (now - self._service_settime) > HOUR
        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