let timeout = null;
let lastScrollPosition = 0;
let minifiedHeader = false;
let showMinifiedHeader = false;
let justMinified = false;

function headerContainer() {
	return document.getElementById('header-container');
}

function mobile_header() {
	if (document.getElementById('headerContainerPDA')) {
		return true;
	} else {
		return false;
	}
}

function handleScrollChange(scrollPosition) {
	const bodyTop = document.documentElement.getBoundingClientRect().top;
	const headerHeight = headerContainer().getBoundingClientRect().height;
	const headerTop = window.scrollY * -1;

	const headerBottomVisible = scrollPosition < headerTop + headerHeight - bodyTop;
	const headerTopVisible = scrollPosition <= headerTop - bodyTop;
	const scrollUp = scrollPosition < lastScrollPosition && !justMinified;

	justMinified = !minifiedHeader && !headerBottomVisible;

	if (!headerBottomVisible && !minifiedHeader) {
		minifiedHeader = true;
	} else if (minifiedHeader && headerTopVisible) {
		minifiedHeader = false;
	}

	if (mobile_header()) {
		showMinifiedHeader = minifiedHeader && scrollUp;
	} else {
		showMinifiedHeader = minifiedHeader || justMinified;
	}

	updateLastScrollPosition(scrollPosition);
	updateHeaderClasses();
}

function updateLastScrollPosition(scrollPosition) {
	lastScrollPosition = scrollPosition;
}

function updateHeaderClasses() {
	const h = document.getElementById('header');
	const p = document.getElementsByClassName('pagination_fixed')[0];
	let classes = ['container'];
	if (isMenuOpen) {
		classes.push('open',	'done');
	}
	if (minifiedHeader) {
		classes.push('minified-header');
	}
	if (showMinifiedHeader) {
		classes.push('show-minified-header');
	}
	if (p) {
		if (showMinifiedHeader) {
			addClass(p, 'padding-top-53');
			removeClass(p, 'padding-top-5');
		} else {
			addClass(p, 'padding-top-5');
			removeClass(p, 'padding-top-53');
		}
	}
	h.className = classes.join(' ');
}
window.addEventListener('scroll', function () {
	if (timeout === null) {
		timeout = setTimeout(() => {
			const top = window.pageYOffset ?? document.documentElement.scrollTop;
			handleScrollChange(top);
			timeout = null;
		}, 300)
	}
})