import React, { useCallback, useState } from '../lib/teact/teact';
import { getGlobal } from '../lib/teact/teactn';

import { SCHEDULED_WHEN_ONLINE } from '../config';
import { getDayStartAt } from '../util/dateFormat';
import useLang from './useLang';

import CalendarModal from '../components/common/CalendarModal.async';

type OnScheduledCallback = (scheduledAt: number) => void;

const useSchedule = (
  canScheduleUntilOnline?: boolean,
  onCancel?: () => void,
) => {
  const lang = useLang();
  const [onScheduled, setOnScheduled] = useState<OnScheduledCallback | undefined>();

  const handleMessageSchedule = useCallback((date: Date, isWhenOnline = false) => {
    const { serverTimeOffset } = getGlobal();
    // Scheduled time can not be less than 10 seconds in future
    const scheduledAt = Math.round(Math.max(date.getTime(), Date.now() + 60 * 1000) / 1000)
      + (isWhenOnline ? 0 : serverTimeOffset);
    onScheduled?.(scheduledAt);
    setOnScheduled(undefined);
  }, [onScheduled]);

  const handleMessageScheduleUntilOnline = useCallback(() => {
    handleMessageSchedule(new Date(SCHEDULED_WHEN_ONLINE * 1000), true);
  }, [handleMessageSchedule]);

  const handleCloseCalendar = useCallback(() => {
    setOnScheduled(undefined);
    onCancel?.();
  }, [onCancel]);

  const requestCalendar = useCallback((whenScheduled: OnScheduledCallback) => {
    setOnScheduled(() => whenScheduled);
  }, []);

  const scheduledDefaultDate = new Date();
  scheduledDefaultDate.setSeconds(0);
  scheduledDefaultDate.setMilliseconds(0);

  const scheduledMaxDate = new Date();
  scheduledMaxDate.setFullYear(scheduledMaxDate.getFullYear() + 1);

  const calendar = (
    <CalendarModal
      isOpen={Boolean(onScheduled)}
      withTimePicker
      selectedAt={scheduledDefaultDate.getTime()}
      maxAt={getDayStartAt(scheduledMaxDate)}
      isFutureMode
      secondButtonLabel={canScheduleUntilOnline ? lang('Schedule.SendWhenOnline') : undefined}
      onClose={handleCloseCalendar}
      onSubmit={handleMessageSchedule}
      onSecondButtonClick={canScheduleUntilOnline ? handleMessageScheduleUntilOnline : undefined}
    />
  );

  return [requestCalendar, calendar] as const;
};

export default useSchedule;