(function () {
  'use strict';

  var DOMAIN_KEYS = ['food', 'beauty', 'medical', 'specialty'];
  var DOMAIN_ALIASES = {
    food: 'food',
    'food-beverage': 'food',
    beauty: 'beauty',
    'beauty-care': 'beauty',
    medical: 'medical',
    'medical-outer': 'medical',
    specialty: 'specialty',
    'special-performance': 'specialty'
  };

  function toArray(list) {
    return Array.prototype.slice.call(list || []);
  }

  function domainFromHash() {
    var raw = window.location.hash.replace(/^#/, '').replace(/^domain-/, '');
    return DOMAIN_ALIASES[raw] || '';
  }

  function replaceDomainHash(domain, prefixed) {
    if (!window.history || !window.history.replaceState) return;
    var hash = prefixed ? '#domain-' + domain : '#' + domain;
    window.history.replaceState(null, '', window.location.pathname + window.location.search + hash);
  }

  function initHomeDomainExplorer() {
    var explorer = document.querySelector('[data-domain-explorer]');
    if (!explorer) return;

    var tabs = toArray(explorer.querySelectorAll('[data-home-domain-tab]'));
    var panels = toArray(explorer.querySelectorAll('[data-home-domain-panel]'));
    if (tabs.length !== DOMAIN_KEYS.length || panels.length !== DOMAIN_KEYS.length) return;

    function activate(domain, options) {
      var selectedTab = null;
      tabs.forEach(function (tab) {
        var selected = tab.getAttribute('data-home-domain-tab') === domain;
        tab.setAttribute('aria-selected', selected ? 'true' : 'false');
        tab.tabIndex = selected ? 0 : -1;
        if (selected) selectedTab = tab;
      });

      panels.forEach(function (panel) {
        var selected = panel.getAttribute('data-home-domain-panel') === domain;
        panel.hidden = !selected;
        panel.setAttribute('aria-hidden', selected ? 'false' : 'true');
      });

      explorer.setAttribute('data-active-domain', domain);
      document.body.setAttribute('data-selected-domain', domain);

      if (options && options.updateHash) replaceDomainHash(domain, true);
      if (options && options.focus && selectedTab) selectedTab.focus();
    }

    tabs.forEach(function (tab, index) {
      tab.addEventListener('click', function () {
        activate(tab.getAttribute('data-home-domain-tab'), { updateHash: true });
      });

      tab.addEventListener('keydown', function (event) {
        var next = index;
        if (event.key === 'ArrowRight') next = (index + 1) % tabs.length;
        else if (event.key === 'ArrowLeft') next = (index - 1 + tabs.length) % tabs.length;
        else if (event.key === 'Home') next = 0;
        else if (event.key === 'End') next = tabs.length - 1;
        else return;

        event.preventDefault();
        activate(tabs[next].getAttribute('data-home-domain-tab'), { updateHash: true, focus: true });
      });
    });

    var initial = domainFromHash();
    activate(initial || 'food', { updateHash: false });

    window.addEventListener('hashchange', function () {
      var requested = domainFromHash();
      if (requested) activate(requested, { updateHash: false });
    });
  }

  function initChallengeDeepLinks() {
    var controls = toArray(document.querySelectorAll('[data-domain-tab]'));
    var panels = toArray(document.querySelectorAll('[data-domain-panel]'));
    if (!controls.length || !panels.length) return;

    function activate(domain, updateHash, focus) {
      var selectedControl = null;
      controls.forEach(function (control) {
        var selected = control.getAttribute('data-domain-tab') === domain;
        control.setAttribute('aria-pressed', selected ? 'true' : 'false');
        if (selected) selectedControl = control;
      });
      panels.forEach(function (panel) {
        panel.hidden = panel.getAttribute('data-domain-panel') !== domain;
      });
      if (updateHash) replaceDomainHash(domain, false);
      if (focus && selectedControl) selectedControl.focus();
    }

    controls.forEach(function (control, index) {
      control.addEventListener('click', function () {
        activate(control.getAttribute('data-domain-tab'), true, false);
      });
      control.addEventListener('keydown', function (event) {
        var next = index;
        if (event.key === 'ArrowRight') next = (index + 1) % controls.length;
        else if (event.key === 'ArrowLeft') next = (index - 1 + controls.length) % controls.length;
        else if (event.key === 'Home') next = 0;
        else if (event.key === 'End') next = controls.length - 1;
        else return;
        event.preventDefault();
        activate(controls[next].getAttribute('data-domain-tab'), true, true);
      });
    });

    var initial = domainFromHash();
    if (initial) activate(initial, false, false);

    window.addEventListener('hashchange', function () {
      var requested = domainFromHash();
      if (requested) activate(requested, false, false);
    });
  }

  function rememberDomainContext() {
    var domain = document.body.getAttribute('data-domain');
    if (!domain) return;
    try {
      window.sessionStorage.setItem('biotenDeveloperDomain', domain);
    } catch (error) {
      /* Storage can be disabled; the page remains fully usable. */
    }
  }

  document.addEventListener('DOMContentLoaded', function () {
    initHomeDomainExplorer();
    initChallengeDeepLinks();
    rememberDomainContext();
  });
}());