import assert from "node:assert/strict";
import { readFile } from "node:fs/promises";
import test from "node:test";
import vm from "node:vm";

const appSource = await readFile(new URL("../app.js", import.meta.url), "utf8");
const helperStart = appSource.indexOf("function createUuid");
const helperEnd = appSource.indexOf("\n\nfunction mapApiOwner", helperStart);
assert.notEqual(helperStart, -1, "createUuid helper should exist");
assert.notEqual(helperEnd, -1, "createUuid helper should end before API mappers");

function loadCreateUuid(windowObject) {
  const context = { window: windowObject };
  vm.runInNewContext(`${appSource.slice(helperStart, helperEnd)}\nglobalThis.createUuid = createUuid;`, context);
  return context.createUuid;
}

test("UUID generation falls back when crypto.randomUUID is unavailable", () => {
  let next = 0;
  const createUuid = loadCreateUuid({
    crypto: {
      getRandomValues(bytes) {
        for (let index = 0; index < bytes.length; index += 1) {
          bytes[index] = next;
          next = (next + 17) % 256;
        }
        return bytes;
      }
    }
  });

  assert.match(
    createUuid(),
    /^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/
  );
});

test("UUID generation uses native randomUUID when it is available", () => {
  const createUuid = loadCreateUuid({
    crypto: {
      randomUUID() {
        return "00000000-0000-4000-8000-000000000123";
      }
    }
  });

  assert.equal(createUuid(), "00000000-0000-4000-8000-000000000123");
});