/**
 * javascript/terminal.js
 *
 * Terminal panel: opens a real, fully interactive terminal inline (as an
 * <iframe>, not a popup window) — the same mechanism Unraid's own webGui
 * uses for its System Terminal and for `docker exec` (see ajax/exec.php's
 * header comment for the full explanation). This module's own job is just:
 *
 *   1. Ask ajax/exec.php to spawn a ttyd instance wrapping
 *      `podman exec -it <container> <shell>`, bound to a unix socket.
 *   2. Point an <iframe> at /logterminal/<sockName>/ — nginx's own
 *      "logterminal" location block (already installed system-wide by
 *      Unraid, not something this plugin configures) proxies that,
 *      WebSocket upgrade included, straight to ttyd's socket.
 *   3. Track which container's session (if any) is currently open, so
 *      "Disconnect" — or opening a different container/shell — can kill
 *      the right ttyd process server-side instead of just discarding the
 *      iframe and leaving it running.
 */
(function () {
  'use strict';
  const P = window.Podman;
  let openName = null;

  function populateContainerSelect(list) {
    const select = P.el('term-container-select');
    if (!select) return;
    const running = list.filter(function (c) { return c.state === 'running'; });
    select.innerHTML = running
      .map(function (c) { return '<option value="' + P.escapeHtml(c.name) + '">' + P.escapeHtml(c.name) + '</option>'; })
      .join('') || '<option value="">No running containers</option>';
  }

  function loadContainers() {
    return P.get('containers', 'list').then(populateContainerSelect);
  }

  function resetFrame(message) {
    P.el('term-frame-wrap').innerHTML = '<p class="podman-empty-note">' + message + '</p>';
    P.el('term-disconnect-btn').disabled = true;
    openName = null;
  }

  /** Best-effort: tells the backend to kill the ttyd/podman-exec session, if any is open. Never rejects. */
  function closeCurrent() {
    if (!openName) return Promise.resolve();
    const name = openName;
    return P.post('exec', 'close', { name: name }).catch(function () {});
  }

  function openLiveTerminal() {
    const name = P.el('term-container-select').value;
    if (!name) return;
    const shell = P.el('term-shell-select').value;
    const wrap = P.el('term-frame-wrap');
    const btn = P.el('term-open-btn');

    wrap.innerHTML = '<p class="podman-empty-note">Opening terminal…</p>';
    btn.disabled = true;
    closeCurrent().then(function () {
      return P.post('exec', 'open', { name: name, shell: shell });
    }).then(function (data) {
      openName = name;
      P.el('term-disconnect-btn').disabled = false;
      // Matches the ~200ms delay Unraid's own openTerminal() uses between
      // asking the backend to spawn ttyd and navigating to its socket —
      // ttyd needs a brief moment to bind before nginx can proxy to it.
      setTimeout(function () {
        wrap.innerHTML = '<iframe class="podman-term-frame" src="/logterminal/' + encodeURIComponent(data.sockName) + '/"></iframe>';
      }, 200);
    }).catch(function (err) {
      resetFrame('Could not open terminal: ' + P.escapeHtml(err.message));
    }).finally(function () {
      btn.disabled = false;
    });
  }

  function disconnect() {
    if (!openName) return;
    const btn = P.el('term-disconnect-btn');
    btn.disabled = true;
    closeCurrent().finally(function () {
      resetFrame('Disconnected. Pick a container and click "Open Terminal" to start a new session.');
    });
  }

  function init() {
    P.el('term-open-btn').addEventListener('click', openLiveTerminal);
    P.el('term-disconnect-btn').addEventListener('click', disconnect);
    return loadContainers();
  }

  // refresh() only repopulates the container select — it must never touch
  // #term-frame-wrap, or an already-open terminal would be torn down out
  // from under the user just by switching tabs and back.
  P.registerPanel('terminal', { init: init, refresh: loadContainers });
})();