#!/usr/bin/env node
// Verify a Predge signed record offline (Node 18+, no packages).
// usage: node verify-record.mjs FILE [--keys FILE_OR_URL] [--offline]
// Same checks and exit codes as verify_record.py (see CANONICALIZATION.md).
import { readFileSync } from "node:fs";
import { createHash, createPublicKey, verify } from "node:crypto";

const KEYS_URL = "https://api.predge.io/.well-known/predge-keys.json";

// The Predge rule: sorted keys at every level, no whitespace. Strings use JSON.stringify,
// which leaves non-ASCII characters as they are (UTF-8 on the wire).
export const canonical = (v) =>
  v === null || typeof v !== "object"
    ? JSON.stringify(v)
    : Array.isArray(v)
      ? `[${v.map(canonical).join(",")}]`
      : `{${Object.keys(v)
          .filter((k) => v[k] !== undefined)
          .sort()
          .map((k) => `${JSON.stringify(k)}:${canonical(v[k])}`)
          .join(",")}}`;

const edVerify = (pubHex, sigHex, message) => {
  try {
    const key = createPublicKey({
      format: "der",
      type: "spki",
      key: Buffer.concat([Buffer.from("302a300506032b6570032100", "hex"), Buffer.from(pubHex, "hex")]),
    });
    return verify(null, Buffer.from(message, "utf8"), key, Buffer.from(sigHex, "hex"));
  } catch {
    return false;
  }
};

async function main(argv) {
  if (!argv[0] || argv[0].startsWith("-")) {
    console.log("usage: node verify-record.mjs FILE [--keys FILE_OR_URL] [--offline]");
    return 64;
  }
  const offline = argv.includes("--offline");
  const keysSrc = argv.includes("--keys") ? argv[argv.indexOf("--keys") + 1] : KEYS_URL;
  const doc = JSON.parse(readFileSync(argv[0], "utf8"));
  const env = doc.attestation && typeof doc.attestation === "object" ? doc.attestation : doc;

  const results = [];
  results.push(["payload rebuilds canonical", canonical(env.payload) === env.canonical]);
  const digest = createHash("sha256").update(env.canonical, "utf8").digest("hex");
  if ("content_hash" in env) results.push(["content_hash = sha256(canonical)", env.content_hash === digest]);
  results.push(["signature over canonical", edVerify(env.public_key, env.signature, env.canonical)]);
  if ("envelope_signature" in env) {
    const { envelope_signature, ...rest } = env;
    results.push(["envelope_signature", edVerify(env.public_key, envelope_signature, canonical(rest))]);
  }
  if (!offline) {
    const keys = /^https?:\/\//.test(keysSrc)
      ? await (await fetch(keysSrc)).json()
      : JSON.parse(readFileSync(keysSrc, "utf8"));
    const pub = env.public_key.toLowerCase();
    results.push([
      "key listed and active in predge-keys.json",
      (keys.keys ?? []).some((k) => k.active && String(k.public_key).toLowerCase() === pub),
    ]);
  }
  console.log("content_hash (sha256 of canonical):", digest);
  console.log("kid:", env.public_key.slice(0, 16));
  for (const [name, ok] of results) console.log(`${ok ? "PASS" : "FAIL"}  ${name}`);
  return results.every(([, ok]) => ok) ? 0 : 1;
}

if (import.meta.url === `file://${process.argv[1]}`) {
  main(process.argv.slice(2)).then((code) => process.exit(code));
}