/*
 * Museum Gallery — Control Room boot.
 *
 * This is the ONLY document in this exhibit that constructs an Exhibit
 * State Core. Every other surface (artifact.html, info-wall.html) attaches
 * to the Core this document creates, over the exhibit-internal bus in
 * surface-bus.js -- see README.md.
 *
 * This document remains fully standalone: nothing below requires any other
 * surface to be open, and nothing below requires XZBT-NGN. The optional
 * HostTransport at the bottom lets an NGN attach later, exactly like every
 * other reference exhibit -- it changes nothing about ordinary operation
 * when no host ever connects.
 */
(function () {
  'use strict';

  var Shell = window.XZBTShell;
  var el = Shell.el;

  var gallery = new window.MuseumGalleryExhibit.Gallery();
  var core = window.MuseumGalleryContract.create(gallery);

  var announcer = new Shell.Announcer({ node: el('announcement'), idleText: 'Control Room standing by.' });

  var artifactSelect = el('artifact-select');
  var artifactDescriptor = core.catalog.get('artifact.selected');
  artifactDescriptor.options.forEach(function (opt) {
    var option = document.createElement('option');
    option.value = opt.value;
    option.textContent = opt.label;
    artifactSelect.appendChild(option);
  });

  var lightingRange = el('lighting-range');
  var rotationRange = el('rotation-range');
  var labelsButton = el('labels-button');
  var subscriberCountEl = el('subscriber-count');

  function sync() {
    var values = core.stateSnapshot().values;
    Shell.setText(el('artifact-name'), window.MuseumGalleryExhibit.ARTIFACT_LABELS[values['artifact.selected']]);
    artifactSelect.value = values['artifact.selected'];

    Shell.setText(el('lighting-readout'), Shell.formatPercent(values['lighting.level']));
    Shell.setText(el('lighting-panel-readout'), Shell.formatPercent(values['lighting.level']));
    lightingRange.value = values['lighting.level'];

    Shell.setText(el('rotation-readout'), values['rotation.speed'].toFixed(1) + 'x');
    Shell.setText(el('rotation-panel-readout'), values['rotation.speed'].toFixed(1) + 'x');
    rotationRange.value = values['rotation.speed'];

    Shell.setText(el('labels-readout'), values['labels.enabled'] ? 'ON' : 'OFF');
    labelsButton.setAttribute('aria-pressed', values['labels.enabled'] ? 'true' : 'false');
  }
  sync();

  /* Every native control here calls the SAME core.applyMutation/invokeAction
   * chokepoint a contract set/invoke (from NGN) or a bus-relayed mutation
   * (from a non-primary surface) would call. There is exactly one path. */
  artifactSelect.addEventListener('change', function () {
    core.applyMutation('artifact.selected', artifactSelect.value, 'ui');
  });
  lightingRange.addEventListener('input', function () {
    core.applyMutation('lighting.level', parseFloat(lightingRange.value), 'ui');
  });
  rotationRange.addEventListener('input', function () {
    core.applyMutation('rotation.speed', parseFloat(rotationRange.value), 'ui');
  });
  labelsButton.addEventListener('click', function () {
    var current = core.stateSnapshot().values['labels.enabled'];
    core.applyMutation('labels.enabled', !current, 'ui');
  });
  el('flash-button').addEventListener('click', function () {
    core.invokeAction('action.spotlight-flash', {}, 'ui');
    announcer.flash('Spotlight flashed.');
  });

  /* The bus owner forwards every core event (however it originated -- this
   * document's own controls, or a mutate request relayed from another
   * surface) to attached surfaces, and answers their attach requests with a
   * fresh snapshot read straight from this Core -- never a second
   * computation. */
  function updateSubscriberCount(count) {
    Shell.setText(subscriberCountEl, String(count));
  }
  var bus = window.MuseumGallerySurfaceBus.createOwner(core, {
    onConnectionChange: updateSubscriberCount
  });
  updateSubscriberCount(bus.attachedCount());
  var priorOnEvent = core.onEvent;
  core.onEvent = function (event) {
    if (typeof priorOnEvent === 'function') priorOnEvent(event);
    sync();
  };

  /* Optional NGN attachment -- same optional transport every reference
   * exhibit includes. Museum Gallery Phase 6.2 does not exercise this path;
   * see the verification document's known-limitations section. */
  var transport = new window.XZBTHostTransport({
    core: core,
    onMessage: function () { el('contract-status').textContent = 'host attached'; }
  });

  window.__museumGalleryDebug = { core: core, gallery: gallery, bus: bus, transport: transport, sync: sync };
})();