document.addEventListener('scroll', function () {
	progress();
	// hideSidebar();
});

window.addEventListener("load", function () {
	progress();
});

nodeBigSize = "25px";
nodeDefaultSize = "16px";

function progress() {
	const sections = document.getElementsByTagName("section");
	const nodes = document.getElementsByClassName("node");

	if (nodes[0]) {
		for (var i = 0; i < sections.length; i++) {
			if (isInViewport(sections[i])) {
				nodes[i].style.width = nodeBigSize;
				nodes[i].style.height = nodeBigSize;
				nodes[i].style.backgroundColor = "black";
			}
			else {
				nodes[i].style.width = nodeDefaultSize;
				nodes[i].style.height = nodeDefaultSize;
				nodes[i].style.backgroundColor = "#555";
			}
		}
	}
}

function hideSidebar() {
	const sidebar = document.getElementById("sidebar");
	const progressContainer = document.getElementById("progressContainer");
	const sections = document.getElementsByTagName("section");

	if (!progressContainer) {
	return;
	}

	if (screen.width <= 600) {
		if (window.scrollY >= 100) {
			sidebar.style.left = "-80px";

			for (var i = 0; i < sections.length; i++) {
				sections[i].style.marginLeft = 0;
			}

			if (progressContainer) {
				progressContainer.style.left = "-11px";
			}
		}
		else {
			sidebar.style.left = "0";

			for (var i = 0; i < sections.length; i++) {
				sections[i].style.marginLeft = "70px";
			}

			if (progressContainer) {
				progressContainer.style.left = "61px";
			}
		}
	}
	else {
		sidebar.style.left = "0";
		progressContainer.style.left = "61px";
	}
}

// Imagine a line in the middle of your viewport.
// Hence, it moves along gas you scroll.
// If this line is inside the element, returns true, else false.
function isInViewport(element) {
	const rect = element.getBoundingClientRect();
	const scroll = window.scrollY;
	const position = window.scrollY + window.innerHeight / 2;
	if (position < rect.bottom + scroll && position > rect.top + scroll) return true;
	else return false;
}