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

export function useCountUp(target: number, duration: number = 1000): number {
  const [current, setCurrent] = useState(0);
  const rafRef = useRef<number>(0);
  const currentRef = useRef<number>(0);

  useEffect(() => {
    if (target === 0) {
      setCurrent(0);
      currentRef.current = 0;
      return;
    }

    const startTime = performance.now();
    const startValue = currentRef.current;

    const animate = (now: number) => {
      const elapsed = now - startTime;
      const t = Math.min(elapsed / duration, 1);
      // ease-out cubic: 1 - (1-t)^3
      const eased = 1 - Math.pow(1 - t, 3);
      const value = Math.round(startValue + (target - startValue) * eased);
      setCurrent(value);
      currentRef.current = value;

      if (t < 1) {
        rafRef.current = requestAnimationFrame(animate);
      }
    };

    rafRef.current = requestAnimationFrame(animate);

    return () => {
      if (rafRef.current) {
        cancelAnimationFrame(rafRef.current);
      }
    };
  }, [target, duration]);

  return current;
}