(function () {
  'use strict';

  function setStatus(msg) {
    var el = document.getElementById('hub-download-apk-status');
    if (el) {
      el.textContent = msg;
    }
  }

  function resolveStableApkUrl() {
    return fetch('/v0/ota/channel/stable.json', { cache: 'no-store' })
      .then(function (r) {
        if (!r.ok) {
          throw new Error('stable channel HTTP ' + r.status);
        }
        return r.json();
      })
      .then(function (channel) {
        var manifestUrl = channel && channel.manifestUrl;
        if (!manifestUrl) {
          throw new Error('stable.json missing manifestUrl');
        }
        return fetch(manifestUrl, { cache: 'no-store' }).then(function (r) {
          if (!r.ok) {
            throw new Error('manifest HTTP ' + r.status);
          }
          return r.json();
        });
      })
      .then(function (manifest) {
        var url = manifest && (manifest.apkUrl || manifest.bundleUrl);
        if (!url) {
          throw new Error('manifest missing apkUrl');
        }
        return url;
      });
  }

  function wireApkButton() {
    var btn = document.getElementById('hub-download-apk');
    if (!btn) {
      return;
    }
    btn.addEventListener('click', function () {
      btn.disabled = true;
      setStatus('Resolving stable OTA channel…');
      resolveStableApkUrl()
        .then(function (url) {
          setStatus('Downloading…');
          window.location.href = url;
        })
        .catch(function (err) {
          setStatus('APK unavailable — run builder OTA publish (stable). ' + (err.message || err));
        })
        .finally(function () {
          btn.disabled = false;
        });
    });
  }

  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', wireApkButton);
  } else {
    wireApkButton();
  }
})();