import { lstat, readFile, readdir } from "node:fs/promises";
import path from "node:path";
import { fileURLToPath } from "node:url";

const root = path.resolve(path.dirname(fileURLToPath(import.meta.url)), "..");
const engineDirectory = path.join(root, "dist", "engines");
const details = await lstat(engineDirectory);
if (details.isSymbolicLink() || !details.isDirectory()) {
  throw new Error("dist/engines must be a real directory.");
}

const entries = (await readdir(engineDirectory, { withFileTypes: true })).sort(
  (left, right) =>
    left.name < right.name ? -1 : left.name > right.name ? 1 : 0,
);
if (
  entries.length !== 1 ||
  !entries[0]?.isFile() ||
  entries[0].name !== "README.md"
) {
  throw new Error(
    "Regex Tools 0.1.0 must not ship an undeclared external engine pack.",
  );
}

const notice = await readFile(path.join(engineDirectory, "README.md"), "utf8");
if (
  !notice.includes("native `RegExp`") ||
  !notice.includes("no external engine")
) {
  throw new Error("The engine asset notice does not describe this release.");
}

console.log("Verified ECMAScript-only engine assets (no WebAssembly pack).");