import { assertEquals } from "@std/assert";
import { ICMPV6_TYPE, icmpv6Message } from "@binstruct/icmpv6";

const coder = icmpv6Message();
// First 4 body bytes are the unused field, followed by as much of the
// invoking packet as fits.
const body = new Uint8Array([0x00, 0x00, 0x00, 0x00]);
const message = {
  type: ICMPV6_TYPE.DEST_UNREACHABLE,
  code: 4,
  checksum: 0x1234,
  body,
};

const buffer = new Uint8Array(4 + body.length);
const bytesWritten = coder.encode(message, buffer);
const [decoded, bytesRead] = coder.decode(buffer);

assertEquals(bytesWritten, buffer.length);
assertEquals(bytesRead, buffer.length);
assertEquals(decoded.type, ICMPV6_TYPE.DEST_UNREACHABLE);
assertEquals(decoded.code, 4);
assertEquals(decoded.checksum, 0x1234);
assertEquals(decoded.body, body);