import { useRef, useState, useEffect } from 'react';

interface TimeLeft {
  secondsLeft: string;
  minutesLeft: string;
  hoursLeft: string;
  daysLeft: string;
  isOver: boolean;
  currentEndDate: number;
}

const addZero = (value: number): string =>
  value < 10.0 ? `0${value.toString()}` : value.toString();

const formatTime = (time: number, hasZeroes: boolean): string =>
  hasZeroes ? addZero(time) : time.toString();

const calculateTimeLeft = (endDate: number, hasZeroes: boolean): TimeLeft => {
  const distance = endDate - Date.now();

  const seconds = Math.floor(distance / 1000.0);
  const minutes = Math.floor(seconds / 60.0);
  const hours = Math.floor(minutes / 60.0);
  const days = Math.floor(hours / 24.0);

  return {
    secondsLeft: formatTime(Math.floor(seconds % 60.0), hasZeroes),
    minutesLeft: formatTime(Math.floor(minutes % 60.0), hasZeroes),
    hoursLeft: formatTime(Math.floor(hours % 24.0), hasZeroes),
    daysLeft: formatTime(days % 365.0, hasZeroes),
    isOver: Date.now() > endDate,
    currentEndDate: endDate,
  };
};

export type UseTimer = [TimeLeft, React.Dispatch<React.SetStateAction<number>>];

export const useTimer = (
  countdownDate: number,
  hasZeroes: boolean,
): UseTimer => {
  const animationFrameId = useRef(0);

  const [endDate, setEndDate] = useState<number>(countdownDate);
  const [timeLeft, setTimeLeft] = useState<TimeLeft>(
    calculateTimeLeft(endDate, hasZeroes),
  );

  useEffect(() => {
    animationFrameId.current = requestAnimationFrame(() =>
      setTimeLeft(calculateTimeLeft(endDate, hasZeroes)),
    );

    return (): void => cancelAnimationFrame(animationFrameId.current);
  }, [endDate, timeLeft, hasZeroes]);

  return [timeLeft, setEndDate];
};

export default useTimer;