export function progressBar(){
  const bar = document.getElementById('progressBar');
  if (!bar) return;

  window.addEventListener('scroll', () => {
    const scrollTop = window.scrollY;
    const docHeight = document.documentElement.scrollHeight - window.innerHeight;
    const progress = docHeight > 0 ? (scrollTop / docHeight) * 100 : 0;
    bar.style.width = `${progress}vw`;
  }, { passive: true });
}


export function scrollBack(){
  const bottomBar = document.getElementById('bottom-bar');
  const navInvestigation = document.getElementById('nav-investigation');
  const header = document.getElementById('site-header');
  const footerEl = document.getElementById('support-bar') || document.getElementById('site-footer');

  let lastY = window.scrollY;
  let peakY = window.scrollY;
  let visible = false;

  window.addEventListener('scroll', () => {
    const currentY = window.scrollY;

    // header : basé uniquement sur la position absolue
    if (navInvestigation && header) {
      header.classList.toggle('has-nav-investigation', currentY >= 160);
    }

    // zone footer : bottom-bar masquée et verrouillée
    const inFooterZone = footerEl && (currentY + window.innerHeight >= footerEl.offsetTop);

    if (inFooterZone) {
      if (visible) {
        visible = false;
        if (bottomBar) bottomBar.classList.remove('is-visible');
      }
    } else if (currentY > lastY) {
      // scroll bas
      peakY = currentY;
      if (!visible && currentY > 280) {
        visible = true;
        if (bottomBar) bottomBar.classList.add('is-visible');
      }
    } else {
      // scroll haut : hide après 200px remontés
      if (visible && peakY - currentY >= 200) {
        visible = false;
        if (bottomBar) bottomBar.classList.remove('is-visible');
      }
    }

    lastY = currentY;
  }, { passive: true });
}