import { useEffect, useState, useCallback } from "react";

function useTimer(speed = 1) {
  const [paused, setPaused] = useState(true);
  const play = useCallback(() => setPaused(false), []);
  const pause = useCallback(() => setPaused(true), []);

  const [currentMillisecond, setCurrentMillisecond] = useState(0);
  const reset = useCallback(() => setCurrentMillisecond(0), []);

  useEffect(() => {
    if (!paused) {
      let last = Date.now();
      const timer = window.setInterval(() => {
        const now = Date.now();
        setCurrentMillisecond((cm) => cm + (now - last) * speed);
        last = now;
      }, 97);
      return () => window.clearInterval(timer);
    }
  }, [paused, speed]);

  return {
    currentMillisecond,
    setCurrentMillisecond,
    reset,
    paused,
    play,
    pause
  };
}

export default useTimer;