const sites = ["~jigong", "rafhei0"];

function getRandomSite(ignore) {
	// get random index from sites
	const index = Math.floor(Math.random() * sites.length);
	// if random site is referrer, retry
	return index === ignore ? getRandomSite(ignore) : sites[index];
}

const validRedirectTypes = ["next", "previous", "random"];

// parse url params
const params = new URLSearchParams(window.location.search);
let referrerUrl = params.get("referrer");
let type = params.get("type") || "random"; // default to random if no type given

if (!validRedirectTypes.includes(type)) {
	// default to random is type not valid
	type = "random";
}

if (!sites.includes(referrerUrl)) {
	// referrer url is incorrect, select random referrer from sites list,
	referrerUrl = sites[Math.floor(Math.random() * sites.length)];
	// select random site, and redirect to it
	window.location.href = sites[Math.floor(Math.random() * sites.length)];
}

// get index of the referrer url
const referrerIndex = sites.indexOf(referrerUrl);
let redirect;
if (type === "random") {
	redirect = getRandomSite(referrerIndex);
} else if (type === "next") {
	// get index of next website in list
	let nextIndex = referrerIndex + 1;

	// if index is greater than the length of list, loop back to 0 index
	if (nextIndex > sites.length - 1) {
		nextIndex = 0;
	}

	redirect = sites[nextIndex];
} else {
	// redirect to previous
	let previousIndex = referrerIndex - 1;
	if (previousIndex < 0) {
		// if previous index is less than 0, loop around to last index
		previousIndex = sites.length - 1;
	}

	redirect = sites[previousIndex];
}

if (redirect[0] !== "~") {
	redirect = `~${redirect}`;
}

if (redirect === "~rafhei0") {
	redirect = `https://tilde.green/${redirect}/p/0.html`;
	window.location.href = redirect;
} else {
	redirect = `https://tilde.green/${redirect}/`;
	window.location.href = redirect;
}