{% comment %}
  Version switcher for the published docs site.

  The site is deployed as parallel channels on gh-pages:
    /            -> latest published release (default)
    /main/       -> snapshot of the main branch
    /vX.Y.Z/     -> each published release

  Which channel this build belongs to is inferred from site.baseurl
  (e.g. "/Meshtastic-Android", "/Meshtastic-Android/main",
  "/Meshtastic-Android/v2.9.0"). The available versions are read at runtime
  from /versions.json at the site root, which is regenerated on every deploy
  by scripts/docs/publish-to-gh-pages.sh. When versions.json is unavailable
  (e.g. local `jekyll serve`), the switcher stays hidden.
{% endcomment %}

<details class="language-switcher version-switcher" id="version-switcher" aria-label="Documentation version" hidden>
  <summary class="language-switcher-btn" title="Switch documentation version">
    🏷️ <span id="version-current"></span>
  </summary>
  <ul class="language-switcher-list" id="version-switcher-list"></ul>
</details>

<script>
(function() {
  var baseurl = '{{ site.baseurl }}';
  var root = baseurl;
  var channel = 'latest';
  // /main/, /vX.Y.Z/ or a prerelease snapshot like /v2.8.0-open.1/.
  var match = baseurl.match(/^(.*)\/(main|v\d+\.\d+\.\d+(?:-(?:open|closed)\.\d+)?)$/);
  if (match) {
    root = match[1];
    channel = match[2];
  }

  fetch(root + '/versions.json')
    .then(function(res) { return res.ok ? res.json() : Promise.reject(); })
    .then(function(data) {
      var switcher = document.getElementById('version-switcher');
      var list = document.getElementById('version-switcher-list');
      var current = document.getElementById('version-current');
      if (!switcher || !list || !current) return;

      // Keep the reader on the same page when switching channels; a page
      // that doesn't exist in the target version lands on the 404 page.
      var relativePath = location.pathname.slice(baseurl.length) + location.hash;

      var entries = [];
      if (data.latest) {
        entries.push({ id: 'latest', label: 'latest (v' + data.latest + ')', base: root });
      }
      // Prereleases are documented ahead of general availability, so the track
      // is always spelled out — a reader must not mistake a closed-testing
      // snapshot for a shipped release.
      (data.prereleases || []).forEach(function(p) {
        entries.push({
          id: p.dir,
          label: p.dir.replace(/^v/, 'v') + ' — ' + p.track + ' testing',
          base: root + '/' + p.dir
        });
      });
      if (data.hasMain) {
        entries.push({ id: 'main', label: 'main (unreleased snapshot)', base: root + '/main' });
      }
      (data.versions || []).forEach(function(v) {
        entries.push({ id: 'v' + v, label: 'v' + v, base: root + '/v' + v });
      });

      var currentEntry = entries.filter(function(e) { return e.id === channel; })[0];
      current.textContent = currentEntry ? currentEntry.label : channel;

      var others = entries.filter(function(e) { return e.id !== channel; });
      if (others.length === 0) return;

      others.forEach(function(e) {
        var li = document.createElement('li');
        var a = document.createElement('a');
        a.href = e.base + relativePath;
        a.textContent = e.label;
        li.appendChild(a);
        list.appendChild(li);
      });
      switcher.hidden = false;
    })
    .catch(function() { /* no manifest (local build) — leave switcher hidden */ });
})();
</script>