// handles logic related to user clock display using 24h display / timeZone options.
import dayjs, {Dayjs} from 'dayjs';
import utc from 'dayjs/plugin/utc';
import timezone from 'dayjs/plugin/timezone';

dayjs.extend(utc)
dayjs.extend(timezone)

interface TimeOptions { is24hClock: boolean, inviteeTimeZone: string };

const timeOptions: TimeOptions = {
  is24hClock: false,
  inviteeTimeZone: '',
}

const isInitialized: boolean = false;

const initClock = () => {
  if (typeof localStorage === "undefined" || isInitialized) {
    return;
  }
  timeOptions.is24hClock = localStorage.getItem('timeOption.is24hClock') === "true";
  timeOptions.inviteeTimeZone = localStorage.getItem('timeOption.preferredTimeZone') || dayjs.tz.guess();
}

const is24h = (is24hClock?: boolean) => {
  initClock();
  if(typeof is24hClock !== "undefined") set24hClock(is24hClock);
  return timeOptions.is24hClock;
}

const set24hClock = (is24hClock: boolean) => {
  localStorage.setItem('timeOption.is24hClock', is24hClock.toString());
  timeOptions.is24hClock = is24hClock;
}

function setTimeZone(selectedTimeZone: string) {
  localStorage.setItem('timeOption.preferredTimeZone', selectedTimeZone);
  timeOptions.inviteeTimeZone = selectedTimeZone;
}

const timeZone = (selectedTimeZone?: string) => {
  initClock();
  if (selectedTimeZone) setTimeZone(selectedTimeZone)
  return timeOptions.inviteeTimeZone;
}

export {is24h, timeZone};