export function mountSiteHeader() {
	const headerEl = document.querySelector<HTMLElement>(".c-site-header");

	if (headerEl) {
		const navbarEl = headerEl?.querySelector(".o-navbar--static-white");
		const logoEl = headerEl?.querySelector(".c-logo--static-white");
		const buttonEls = headerEl?.querySelectorAll(".o-button--static-white");

		let settings: IntersectionObserverInit;

		const boundingRect = headerEl.getBoundingClientRect();

		if (boundingRect.top > 0) {
			settings = {
				rootMargin: "1px 0px -100% 0px",
			};
		} else {
			settings = {
				root: document.documentElement,
				rootMargin: "-1px 0px 0px 0px",
				threshold: [1],
			};
		}

		const observer = new IntersectionObserver(([e]) => {
			const scroll = e?.isIntersecting;
			headerEl.classList.toggle("is-scroll", scroll);
			navbarEl?.classList.toggle("o-navbar--static-white", !scroll);
			logoEl?.classList.toggle("c-logo--static-white", !scroll);
			for (const buttonEl of buttonEls) {
				buttonEl.classList.toggle("o-button--static-white", !scroll);
			}
		}, settings);

		observer.observe(headerEl);
	}
}