import dns from "dns";
import ipRangeCheck from "ip-range-check";

const subnets = [
  "0.0.0.0/8",
  "127.0.0.0/8",
  "10.0.0.0/8",
  "100.64.0.0/10",
  "169.254.0.0/16",
  "172.16.0.0/12",
  "192.0.0.0/24",
  "192.0.2.0/24",
  "192.88.99.0/24",
  "192.168.0.0/16",
  "198.18.0.0/15",
  "198.51.100.0/24",
  "203.0.113.0/24",
  "224.0.0.0/4",
  "233.252.0.0/24",
  "240.0.0.0/4",
  "255.255.255.255/32",
  "::/128",
  "::1/128",
  "::ffff:0:0/96",
  "::ffff:0:0:0/96",
  "64:ff9b::/96",
  "64:ff9b:1::/48",
  "100::/64",
  "2001:0000::/32",
  "2001:20::/28",
  "2001:db8::/32",
  "2002::/16",
  "fc00::/7",
  "fe80::/64",
  "ff00::/8",
];

export default async function isLocalResource(url: URL): Promise<boolean> {
  // Resolve domain name
  const addr = (
    await dns.promises.lookup(url.hostname)
  ).address;

  // Check if IP is in local network
  return ipRangeCheck(addr, subnets);
}