/* Shared hooks: scroll reveal + active section tracking */

function useReveal() {
  React.useEffect(() => {
    document.body.classList.add('reveal-ready');
    const els = document.querySelectorAll('.reveal');
    if (!('IntersectionObserver' in window)) {
      els.forEach((el) => el.classList.add('in'));
      return;
    }
    const revealIfVisible = (el) => {
      const rect = el.getBoundingClientRect();
      if (rect.top < window.innerHeight - 60 && rect.bottom > 0) {
        el.classList.add('in');
        return true;
      }
      return false;
    };
    const io = new IntersectionObserver(
      (entries) => {
        entries.forEach((entry) => {
          if (entry.isIntersecting) {
            entry.target.classList.add('in');
            io.unobserve(entry.target);
          }
        });
      },
      { threshold: 0.15, rootMargin: '0px 0px -60px 0px' }
    );
    els.forEach((el) => {
      if (!revealIfVisible(el)) io.observe(el);
    });
    return () => io.disconnect();
  }, []);
}

function useActiveSection(ids) {
  const [active, setActive] = React.useState(ids[0]);
  React.useEffect(() => {
    const handler = () => {
      const y = window.scrollY + 140;
      let current = ids[0];
      for (const id of ids) {
        const el = document.getElementById(id);
        if (el && el.offsetTop <= y) current = id;
      }
      setActive(current);
    };
    handler();
    window.addEventListener('scroll', handler, { passive: true });
    return () => window.removeEventListener('scroll', handler);
  }, [ids.join(',')]);
  return active;
}

Object.assign(window, { useReveal, useActiveSection });