import { isHTMLElement } from './is-element.mjs';

function isScrollParent(el) {
  const win = el.ownerDocument.defaultView || window;
  const { overflow, overflowX, overflowY } = win.getComputedStyle(el);
  return /auto|scroll|overlay|hidden/.test(overflow + overflowY + overflowX);
}
function getParent(el) {
  if (el.localName === "html")
    return el;
  return el.assignedSlot || el.parentElement || el.ownerDocument.documentElement;
}
function getScrollParent(el) {
  if (["html", "body", "#document"].includes(el.localName)) {
    return el.ownerDocument.body;
  }
  if (isHTMLElement(el) && isScrollParent(el)) {
    return el;
  }
  return getScrollParent(getParent(el));
}

export { getScrollParent };