(function () {
  var LOGO_URL = '/fb-logo.png?v=20260306w';
  var HOME_SEARCH_CACHE_KEY = 'fb.home.search.q';
  function setFavicons() {
    var rels = ['icon', 'shortcut icon', 'apple-touch-icon'];
    rels.forEach(function (rel) {
      var link = document.querySelector('link[rel="' + rel + '"]');
      if (!link) {
        link = document.createElement('link');
        link.setAttribute('rel', rel);
        document.head.appendChild(link);
      }
      link.setAttribute('href', LOGO_URL);
      link.setAttribute('type', 'image/png');
    });
    var msTile = document.querySelector('meta[name="msapplication-TileImage"]');
    if (msTile) msTile.setAttribute('content', LOGO_URL);
  }

  function ensureStaticStyles() {
    if (document.getElementById('fb-brand-style')) return;
    var style = document.createElement('style');
    style.id = 'fb-brand-style';
    style.textContent = [
      '.credits { display: none !important; }',
      '[class*="credits"] { display: none !important; }',
      '#fb-header-brand {',
      '  display: inline-flex;',
      '  align-items: center;',
      '  margin-right: 10px;',
      '  line-height: 1;',
      '  pointer-events: none;',
      '  user-select: none;',
      '}',
      '#fb-header-brand img { width: 26px; height: 26px; object-fit: contain; display:block; }',
      '#fb-top-corner-brand {',
      '  position: fixed;',
      '  top: 10px;',
      '  left: 12px;',
      '  z-index: 2147483000;',
      '  display: inline-flex;',
      '  align-items: center;',
      '  justify-content: center;',
      '  width: 40px;',
      '  height: 40px;',
      '  border-radius: 10px;',
      '  background: rgba(41,44,60,.75);',
      '  border: 1px solid rgba(198,208,245,.25);',
      '  backdrop-filter: blur(8px);',
      '  pointer-events: none;',
      '  user-select: none;',
      '}',
      '#fb-top-corner-brand img { width: 22px; height: 22px; object-fit: contain; display:block; }',
      'body#login-page #fb-top-corner-brand, #login #fb-top-corner-brand { display: none !important; }',
      'body#login-page #fb-header-brand, #login #fb-header-brand { display: none !important; }',
      '@media (max-width: 736px) { #fb-top-corner-brand { top: 8px; left: 8px; width: 34px; height: 34px; } }'
    ].join('\n');
    document.head.appendChild(style);
  }

  function tuneLoginBrand() {
    var login = document.getElementById('login');
    if (!login) return;
    var form = login.querySelector('form');
    if (!form) return;

    var imgs = form.querySelectorAll('img');
    if (imgs.length > 0) {
      imgs.forEach(function (img, idx) {
        if (idx === 0) {
          if (img.dataset.fbLogoReady !== '1') {
            img.src = LOGO_URL;
            img.srcset = '';
            img.style.width = '92px';
            img.style.height = '92px';
            img.style.objectFit = 'contain';
            img.style.display = 'block';
            img.style.margin = '0 auto 8px';
            img.dataset.fbLogoReady = '1';
          }
        } else {
          img.remove();
        }
      });
    }

    var title = form.querySelector('h1');
    if (title && title.textContent !== '繁星文档') {
      title.textContent = '繁星文档';
      title.style.marginTop = '6px';
    }
  }

  function suppressNativeHeaderBrand() {
    if (location.pathname.indexOf('/login') === 0 || document.getElementById('login')) return;
    var header = document.querySelector('header');
    if (!header) return;

    var walker = document.createTreeWalker(header, NodeFilter.SHOW_TEXT, null);
    var node;
    while ((node = walker.nextNode())) {
      var txt = (node.nodeValue || '').trim();
      if (txt === 'File Browser' || txt === '文件浏览器') {
        node.nodeValue = '';
      }
    }

    var nativeImgs = header.querySelectorAll('img:not(#fb-header-brand img)');
    nativeImgs.forEach(function (img) {
      if (img.closest && img.closest('#fb-header-brand')) return;
      img.style.display = 'none';
    });
  }

  function ensureHeaderBrand() {
    var onLogin = location.pathname.indexOf('/login') === 0 || !!document.getElementById('login');
    var old = document.getElementById('fb-header-brand');
    if (onLogin) {
      if (old) old.remove();
      return false;
    }

    var header = document.querySelector('header');
    if (!header) return false;

    var brand = old;
    if (!brand) {
      brand = document.createElement('div');
      brand.id = 'fb-header-brand';
      brand.setAttribute('aria-hidden', 'true');
      brand.innerHTML = '<img src="' + LOGO_URL + '" alt="logo" />';
      header.insertBefore(brand, header.firstChild);
    } else {
      var img = brand.querySelector('img');
      if (img) img.src = LOGO_URL;
      if (brand.parentElement !== header) {
        header.insertBefore(brand, header.firstChild);
      }
    }
    return true;
  }

  function ensureTopCornerFallback(useHeader) {
    var onLogin = location.pathname.indexOf('/login') === 0 || !!document.getElementById('login');
    var el = document.getElementById('fb-top-corner-brand');

    if (onLogin || useHeader) {
      if (el) el.remove();
      return;
    }

    if (!el) {
      el = document.createElement('div');
      el.id = 'fb-top-corner-brand';
      el.setAttribute('aria-hidden', 'true');
      el.innerHTML = '<img src="' + LOGO_URL + '" alt="logo" />';
      document.body.appendChild(el);
    } else {
      var img = el.querySelector('img');
      if (img) img.src = LOGO_URL;
    }
  }

  function renameSidebarRoot() {
    var walker = document.createTreeWalker(document.body, NodeFilter.SHOW_TEXT, null);
    var node;
    while ((node = walker.nextNode())) {
      var txt = (node.nodeValue || '').trim();
      if (txt === '我的文件' || txt === 'My Files') {
        node.nodeValue = node.nodeValue.replace(txt, '繁星文档');
      }
    }
  }

  function removeLegacyInlineSearch() {
    var legacy = document.getElementById('fb-inline-search');
    if (legacy) legacy.remove();
    var legacyStyle = document.getElementById('fb-inline-search-style');
    if (legacyStyle) legacyStyle.remove();
    var search = document.getElementById('search');
    if (search && search.style && search.style.display === 'none') search.style.display = '';
  }

  function isSearchInput(el) {
    if (!el || el.tagName !== 'INPUT') return false;
    var t = (el.getAttribute('type') || '').toLowerCase();
    var p = (el.getAttribute('placeholder') || '').toLowerCase();
    if (t === 'search') return true;
    if (p.indexOf('search') >= 0 || p.indexOf('搜索') >= 0) return true;
    if ((el.className || '').toString().toLowerCase().indexOf('search') >= 0) return true;
    return false;
  }

  function readCachedHomeSearch() {
    try {
      return (sessionStorage.getItem(HOME_SEARCH_CACHE_KEY) || '').trim();
    } catch (e) {
      return '';
    }
  }

  function writeCachedHomeSearch(q) {
    try {
      sessionStorage.setItem(HOME_SEARCH_CACHE_KEY, (q || '').trim());
    } catch (e) {}
  }

  function goSearch(q) {
    if (location.pathname === '/search') return;
    var qs = (q || '').trim();
    if (!qs) qs = readCachedHomeSearch();
    location.assign('/search' + (qs ? ('?q=' + encodeURIComponent(qs)) : ''));
  }

  function installSearchRedirectGuards() {
    if (window.__fbSearchRedirectGuardInstalled) return;
    window.__fbSearchRedirectGuardInstalled = true;

    // Keep home search input value cached for /search fallback.
    document.addEventListener('input', function (e) {
      if (location.pathname.indexOf('/login') === 0) return;
      var homeInput = e.target && e.target.closest && e.target.closest('#search input, #search #input input');
      if (!homeInput) return;
      writeCachedHomeSearch(e.target.value || '');
    }, true);

    document.addEventListener('click', function (e) {
      if (location.pathname.indexOf('/login') === 0) return;

      var inSearch = e.target && e.target.closest && e.target.closest('#search');
      if (!inSearch) return;

      var onInput = e.target && e.target.closest && e.target.closest('#search input, #search #input input');
      if (onInput) return; // keep typing, no redirect on click.

      // Intercept magnifier / action click to prevent built-in index popup.
      var icon = e.target && e.target.closest && e.target.closest('.search-button,header .search-button,#search #input > i,#search .search-button,#search .action,#search [title*="search" i],#search [aria-label*="search" i],#search [title*="搜索" i],#search [aria-label*="搜索" i],#search i');
      if (!icon) return;

      e.preventDefault();
      e.stopPropagation();
      if (e.stopImmediatePropagation) e.stopImmediatePropagation();
    }, true);

    document.addEventListener('keydown', function (e) {
      if (location.pathname.indexOf('/login') === 0) return;
      if (location.pathname === '/search') return;

      var homeInput = e.target && e.target.closest && e.target.closest('#search input, #search #input input');
      if (!homeInput) return;

      if (e.key !== 'Enter') return;
      var q = (e.target.value || '').trim();
      writeCachedHomeSearch(q);
      e.preventDefault();
      e.stopPropagation();
      if (e.stopImmediatePropagation) e.stopImmediatePropagation();
      goSearch(q);
    }, true);
  }

  function apply() {
    setFavicons();
    ensureStaticStyles();
    tuneLoginBrand();
    suppressNativeHeaderBrand();
    var ok = ensureHeaderBrand();
    ensureTopCornerFallback(ok);
    renameSidebarRoot();
    removeLegacyInlineSearch();
    installSearchRedirectGuards();
  }

  var timer = null;
  var ob = new MutationObserver(function () {
    if (timer) clearTimeout(timer);
    timer = setTimeout(apply, 20);
  });

  ob.observe(document.documentElement, { childList: true, subtree: true });
  apply();
  if (window.requestAnimationFrame) requestAnimationFrame(apply);
  setTimeout(apply, 30);
})();