const DEFAULT_PATH = "pi-sync";

export function normalizeWebDavIdentityUrl(value: string) {
	try {
		const url = new URL(value.trim());
		url.username = "";
		url.password = "";
		url.search = "";
		url.hash = "";
		url.pathname = `${url.pathname.replace(/\/+$/u, "")}/`;
		return url.toString();
	} catch {
		return value.trim();
	}
}

export function normalizeWebDavUrl(value: string | undefined) {
	const normalized = normalizeOptionalString(value);
	if (!normalized) return undefined;
	let url: URL;
	try {
		url = new URL(normalized);
	} catch {
		throw new Error("Invalid pi-sync WebDAV URL.");
	}
	if (url.username || url.password || url.search || url.hash) {
		throw new Error(
			"Invalid pi-sync WebDAV URL: credentials, query, and fragment are not allowed.",
		);
	}
	const loopback =
		url.hostname === "127.0.0.1" ||
		url.hostname === "localhost" ||
		url.hostname === "[::1]" ||
		url.hostname === "::1";
	if (url.protocol !== "https:" && !(url.protocol === "http:" && loopback)) {
		throw new Error("Invalid pi-sync WebDAV URL: HTTPS is required except for loopback.");
	}
	url.pathname = `${url.pathname.replace(/\/+$/u, "")}/`;
	return url.toString();
}

export function normalizeWebDavPath(value: string | undefined) {
	const normalized = trimSlashes(normalizeOptionalString(value) ?? DEFAULT_PATH);
	if (
		!normalized ||
		normalized.includes("\\") ||
		hasControlCharacter(normalized) ||
		normalized.split("/").some((segment) => !segment || segment === "." || segment === "..")
	) {
		throw new Error("Invalid pi-sync WebDAV path.");
	}
	return normalized;
}

export function validateWebDavNamespace(value: string) {
	if (
		value === "." ||
		value === ".." ||
		value.includes("/") ||
		value.includes("\\") ||
		hasControlCharacter(value)
	) {
		throw new Error("Invalid pi-sync WebDAV namespace.");
	}
}

export function validateWebDavCredentials(username: string, password?: string) {
	if (
		username.includes(":") ||
		hasControlCharacter(username) ||
		(password !== undefined && hasControlCharacter(password))
	) {
		throw new Error("Invalid pi-sync WebDAV credentials.");
	}
}

function normalizeOptionalString(value: string | undefined) {
	const normalized = value?.trim();
	return normalized || undefined;
}

function trimSlashes(value: string) {
	return value.replace(/^\/+|\/+$/gu, "");
}

function hasControlCharacter(value: string) {
	return [...value].some((character) => {
		const code = character.codePointAt(0) ?? 0;
		return code < 0x20 || (code >= 0x7f && code <= 0x9f);
	});
}