export function createDropdownMenu({
  anchorEl,
  items = [],
  className = '',
  minWidth = 210,
  offset = 7,
  align = 'right',
  onOpen = null,
  onClose = null,
} = {}) {
  let portal = null;

  const close = () => {
    if (!portal) return;
    portal.remove();
    portal = null;
    anchorEl?.setAttribute('aria-expanded', 'false');
    onClose?.();
  };

  const position = () => {
    if (!portal || !anchorEl) return;
    const rect = anchorEl.getBoundingClientRect();
    const margin = 10;
    const menuWidth = portal.offsetWidth || minWidth;
    const desiredLeft = align === 'left' ? rect.left : rect.right - menuWidth;
    const left = Math.max(margin, Math.min(window.innerWidth - menuWidth - margin, desiredLeft));
    let top = rect.bottom + offset;
    const menuHeight = portal.offsetHeight || 180;
    if (top + menuHeight > window.innerHeight - margin) {
      top = Math.max(margin, rect.top - menuHeight - offset);
    }
    portal.style.left = `${Math.round(left)}px`;
    portal.style.top = `${Math.round(top)}px`;
  };

  const open = () => {
    if (!anchorEl || portal) return;
    const menu = document.createElement('div');
    menu.className = `dm-head-menu dm-head-menu--portal shared-dropdown-menu ${className}`.trim();
    menu.setAttribute('role', 'menu');
    menu.style.minWidth = `${minWidth}px`;

    items.forEach((item) => {
      if (item?.divider) {
        const divider = document.createElement('div');
        divider.className = 'channel-menu-divider';
        menu.append(divider);
        return;
      }
      const btn = document.createElement('button');
      btn.type = 'button';
      btn.className = `dm-head-menu-item shared-dropdown-menu__item${item?.selected ? ' is-selected' : ''}${item?.danger ? ' destructive' : ''}`;
      btn.setAttribute('role', 'menuitem');
      if (item?.iconHtml) {
        const icon = document.createElement('span');
        icon.className = 'shared-dropdown-menu__icon';
        icon.innerHTML = item.iconHtml;
        btn.append(icon);
      } else if (item?.iconSrc) {
        const icon = document.createElement('img');
        icon.src = item.iconSrc;
        icon.alt = '';
        icon.setAttribute('aria-hidden', 'true');
        btn.append(icon);
      }
      const label = document.createElement('span');
      label.textContent = String(item?.label || '');
      btn.append(label);
      btn.addEventListener('click', (event) => {
        event.preventDefault();
        event.stopPropagation();
        close();
        item?.action?.();
      });
      menu.append(btn);
    });

    menu.addEventListener('click', (event) => event.stopPropagation());
    document.body.append(menu);
    portal = menu;
    anchorEl.setAttribute('aria-expanded', 'true');
    onOpen?.();
    position();
  };

  const toggle = () => {
    if (portal) close();
    else open();
  };

  const onAnchorClick = (event) => {
    event.preventDefault();
    event.stopPropagation();
    toggle();
  };
  const onOutsideClick = (event) => {
    if (!portal) return;
    if (portal.contains(event.target) || anchorEl?.contains(event.target)) return;
    close();
  };
  const onKeydown = (event) => {
    if (event.key !== 'Escape' || !portal) return;
    close();
    anchorEl?.focus();
  };

  anchorEl?.setAttribute('aria-haspopup', 'menu');
  anchorEl?.setAttribute('aria-expanded', 'false');
  anchorEl?.addEventListener('click', onAnchorClick);
  document.addEventListener('click', onOutsideClick);
  document.addEventListener('keydown', onKeydown);
  window.addEventListener('resize', position, { passive: true });
  window.addEventListener('scroll', position, { passive: true, capture: true });

  return {
    open,
    close,
    toggle,
    position,
    destroy() {
      close();
      anchorEl?.removeEventListener('click', onAnchorClick);
      document.removeEventListener('click', onOutsideClick);
      document.removeEventListener('keydown', onKeydown);
      window.removeEventListener('resize', position);
      window.removeEventListener('scroll', position, true);
    },
  };
}