// Cross-implementation gate for ECIES thread-key wrapping. The native client
// (ios/LChatCore/Sources/LChatCore/Crypto.swift) reimplements unwrapThreadKey in
// CryptoKit; if the web's crypto.js ever changes the wire format (curve, HKDF
// salt/info, key encodings), the two silently drift and threads stop opening on
// one platform. This test pins the format two ways:
//
//   1. a fresh wrap → unwrap round-trips in JS (crypto.js self-consistency), and
//   2. the committed fixture (LChatCore's Tests/…/Fixtures/thread-key-vector.json)
//      still unwraps to its expected key — the SAME fixture the Swift unit test
//      (`swift test` in ios/LChatCore) consumes.
//
// If (2) fails, crypto.js changed incompatibly: regenerate the fixture (see below)
// and update Crypto.swift to match in the same change.
import { readFileSync, writeFileSync } from "node:fs";
import { fileURLToPath } from "node:url";
import { dirname, join } from "node:path";
import { generateUserKeypair, wrapThreadKey, unwrapThreadKey, bytesToB64url } from "../web/static/crypto.js";

const here = dirname(fileURLToPath(import.meta.url));
const fixturePath = join(here, "..", "ios", "LChatCore", "Tests", "LChatCoreTests", "Fixtures", "thread-key-vector.json");

// A known 32-byte thread key (bytes 0..31), so the expected value is stable.
function knownThreadKeyB64() {
  const raw = new Uint8Array(32);
  for (let i = 0; i < 32; i++) raw[i] = i;
  return bytesToB64url(raw);
}

function assert(cond, msg) {
  if (!cond) {
    console.error("FAIL:", msg);
    process.exit(1);
  }
}

// `node test/threadkey.test.mjs --emit` regenerates the committed fixture (the wrap
// uses a random ephemeral key, so the fixture must be frozen, not recomputed).
async function emit() {
  const expectedThreadKeyB64 = knownThreadKeyB64();
  const kp = await generateUserKeypair();
  const wrappedB64 = await wrapThreadKey(expectedThreadKeyB64, kp.publicKey);
  assert((await unwrapThreadKey(wrappedB64, kp.privateKey)) === expectedThreadKeyB64, "round-trip");
  const fixture = {
    _comment:
      "ECIES thread-key test vector. Generated by test/threadkey.test.mjs from " +
      "web/static/crypto.js. LChatCore's ECIESVectorTests unwraps wrappedB64 with " +
      "privPkcs8B64 and must get expectedThreadKeyB64 — a cross-implementation gate " +
      "so the native ECIES never drifts from the web's. base64url throughout. " +
      "Regenerate with: node test/threadkey.test.mjs --emit",
    privPkcs8B64: kp.privateKey,
    pubRawB64: kp.publicKey,
    wrappedB64,
    expectedThreadKeyB64,
  };
  writeFileSync(fixturePath, JSON.stringify(fixture, null, 2) + "\n");
  console.log("wrote", fixturePath);
}

async function test() {
  // (1) crypto.js self-consistency.
  const k = knownThreadKeyB64();
  const kp = await generateUserKeypair();
  const wrapped = await wrapThreadKey(k, kp.publicKey);
  assert((await unwrapThreadKey(wrapped, kp.privateKey)) === k, "fresh wrap/unwrap round-trips");

  // (2) the committed fixture (shared with the Swift test) still unwraps.
  const fx = JSON.parse(readFileSync(fixturePath, "utf8"));
  const got = await unwrapThreadKey(fx.wrappedB64, fx.privPkcs8B64);
  assert(got === fx.expectedThreadKeyB64, "committed fixture unwraps to expected key");

  console.log("threadkey.test.mjs OK");
}

if (process.argv.includes("--emit")) await emit();
else await test();