<!DOCTYPE html>
<script>
const service_worker_unregister = async scope => {
  const absoluteScope = new URL(scope, window.location).href;
  const registration = await navigator.serviceWorker.getRegistration(scope);
  if (registration && registration.scope === absoluteScope) {
    return registration.unregister();
  }
};

const service_worker_reregister = async (url, scope) => {
  if (!scope || scope.length == 0) {
    return Promise.reject(new Error('tests must define a scope'));
  }

  await service_worker_unregister(scope);
  return navigator.serviceWorker.register(url, {'scope': scope});
};

const wait_for_state_activated = worker => {
  if (worker.state === 'activated')
    return Promise.resolve();

  if (worker.state === 'redundant') {
    return Promise.reject(new Error('worker is redundant'));
  }

  return new Promise(function(resolve) {
    worker.addEventListener('statechange', () => {
      if (worker.state === 'activated') {
        resolve();
      }
    });
  });
};

(async () => {
  const script = '/resource-timing/resources/sw.js';
  const scope = '/resource-timing/resources/';
  const registration = await service_worker_reregister(script, scope);
  await wait_for_state_activated(registration.installing);

  const opener = window.opener;
  if (!opener) {
    return;
  }

  opener.postMessage("installed", "*");
  window.addEventListener("message", async e => {
    if (e.data === "unregister") {
      await registration.unregister();
      opener.postMessage("unregistered", "*");
    }
  });

})();

</script>
