/**
 * @file AT Protocol handle resolver
 * @description Resolves AT Protocol handles to DIDs using DNS TXT records
 */

import dns from "node:dns";
import process from "node:process";

const DOT = ".";

/**
 * The AT Protocol DNS TXT record prefix
 * @see https://atproto.com/specs/handle#dns-txt-method
 */
const at_prefix = "_atproto";

/**
 * Callback function for DNS TXT record resolution
 * @param {NodeJS.ErrnoException | null} err - Error object if resolution failed, null otherwise
 * @param {string[][]} addresses - Array of TXT record values returned from DNS lookup
 * @throws {NodeJS.ErrnoException} Throws the error if DNS resolution fails
 */
function resolveCb(err: NodeJS.ErrnoException | null, addresses: string[][]) {
	if (err) {
		throw err;
	}

	const address = addresses[0][0];
	console.info(address);
}

const input = process.argv;

if (input.length !== 3) {
	throw new Error("Please provide a handle to resolve.");
}

const host = input.pop();

/**
 * Get the did record that corresponds to an internet handle
 * see https://atproto.com/specs/handle#dns-txt-method
 */
dns.resolveTxt(at_prefix + DOT + host, resolveCb);