const STATE = {
  mode: "global",
  source: null,
  query: "",
  page: 1,
  pageSize: 100,
  total: 0,
  results: [],
  sources: [],
  sourceMap: {},
  folderTree: [],
  folderTreeSource: null,
  folderNodeMap: {},
  folderCollapsed: {},
  folderSelections: [],
  selectedSources: [],
  minSize: null,
  maxSize: null,
  exact: false,
  fulltext: false,
  searchPaths: true,
  fulltextManifest: null,
  fulltextLoaded: {},
  historyEnabled: true,
  leftSidebarOpen: true,
  rightSidebarOpen: false,
  isMobile: false,
  isDark: true,
  isLoading: false,
  multiSelect: false,
  selectedIds: new Set(),
};

const DOM = {};
const HISTORY_KEY = "vomebook_search_history";
const ICON_HTML = {
  source: '<span class="ui-icon ui-icon-stack" aria-hidden="true"></span>',
  folder: '<span class="ui-icon ui-icon-folder" aria-hidden="true"></span>',
  file: '<span class="ui-icon ui-icon-file" aria-hidden="true"></span>',
};

function $(selector) {
  return document.querySelector(selector);
}

function escapeHTML(value) {
  return String(value).replace(/[&<>"']/g, function(ch) {
    return ({ "&": "&amp;", "<": "&lt;", ">": "&gt;", '"': "&quot;", "'": "&#39;" })[ch];
  });
}

function tokenize(text) {
  return Array.from(new Set(String(text || "").toLowerCase().match(/[a-z0-9]+|[\u4e00-\u9fff\u3400-\u4dbf]+/g) || []));
}

function formatSize(bytes) {
  if (!bytes) return "";
  if (bytes < 1024) return bytes + " B";
  if (bytes < 1048576) return (bytes / 1024).toFixed(1).replace(/\.0$/, "") + " KB";
  if (bytes < 1073741824) return (bytes / 1048576).toFixed(1).replace(/\.0$/, "") + " MB";
  return (bytes / 1073741824).toFixed(2).replace(/\.00$/, "") + " GB";
}

function highlightText(text, query) {
  const safeText = escapeHTML(text || "");
  const tokens = tokenize(query).filter(Boolean);
  if (!safeText || !tokens.length) return safeText;
  let output = safeText;
  for (const token of tokens) {
    const pattern = token.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
    output = output.replace(new RegExp(`(${pattern})`, "gi"), "<mark>$1</mark>");
  }
  return output;
}

function bytesFromInput(value, unit) {
  const parsed = parseFloat(value);
  if (Number.isNaN(parsed) || parsed < 0) return null;
  if (unit === "KB") return Math.round(parsed * 1024);
  if (unit === "MB") return Math.round(parsed * 1048576);
  if (unit === "GB") return Math.round(parsed * 1073741824);
  return Math.round(parsed);
}

function buildPath(folder, file) {
  return folder.length ? folder.join("/") + "/" + file : file;
}

const API = {
  async getSources() {
    const resp = await fetch("/api/sources");
    return resp.json();
  },
  async search(body, sourceSlug) {
    const url = sourceSlug ? `/api/search/${sourceSlug}` : "/api/search";
    const resp = await fetch(url, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify(body),
    });
    return resp.json();
  },
  async getFolders(sourceSlug) {
    const resp = await fetch(`/api/folders/${sourceSlug}`);
    return resp.json();
  },
  async getContents(sourceSlug, path) {
    const qs = path ? `?path=${encodeURIComponent(path)}` : "";
    const resp = await fetch(`/api/folders/${sourceSlug}/contents${qs}`);
    return resp.json();
  },
  async preview(docId) {
    const resp = await fetch(`/api/preview/${encodeURIComponent(docId)}`);
    return resp.json();
  },
  async snippet(docId, query) {
    const resp = await fetch(`/api/snippet/${encodeURIComponent(docId)}?q=${encodeURIComponent(query || "")}`);
    return resp.json();
  },
  async random(sourceSlug) {
    const url = sourceSlug ? `/api/random?source=${encodeURIComponent(sourceSlug)}` : "/api/random";
    const resp = await fetch(url);
    return resp.json();
  },
  async fulltextManifest() {
    const resp = await fetch("/api/fulltext-manifest");
    return resp.json();
  },
  async fulltextIndex(path) {
    const resp = await fetch(`/data/${path}`);
    const blob = await resp.blob();
    const ds = new DecompressionStream("gzip");
    const stream = blob.stream().pipeThrough(ds);
    const text = await new Response(stream).text();
    return JSON.parse(text);
  },
};

function cacheDom() {
  DOM.headerTitle = $("#header-title");
  DOM.headerLogo = $("#header-logo");
  DOM.searchInput = $("#search-input");
  DOM.searchHistoryDropdown = $("#search-history-dropdown");
  DOM.hamburgerBtn = $("#hamburger-btn");
  DOM.settingsBtn = $("#settings-btn");
  DOM.mobileToggleBtn = $("#mobile-toggle-btn");
  DOM.mobileToggleIcon = $("#mobile-toggle-icon");
  DOM.themeBtn = $("#theme-btn");
  DOM.leftSidebar = $("#left-sidebar");
  DOM.rightSidebar = $("#right-sidebar");
  DOM.sidebarExpandBtn = $("#sidebar-expand-btn");
  DOM.sidebarTitle = $("#sidebar-title");
  DOM.sidebarContent = $("#sidebar-content");
  DOM.resultCount = $("#result-count");
  DOM.resultsContainer = $("#results-container");
  DOM.resultsList = $("#results-list");
  DOM.resultsLoading = $("#results-loading");
  DOM.emptyState = $("#empty-state");
  DOM.emptyDesc = $("#empty-desc");
  DOM.emptyRandomBtn = $("#empty-random-btn");
  DOM.loadInfo = $("#load-info");
  DOM.loadedCount = $("#loaded-count");
  DOM.totalCount = $("#total-count");
  DOM.didYouMean = $("#did-you-mean");
  DOM.clearFiltersBtn = $("#clear-filters-btn");
  DOM.sortSelect = $("#sort-select");
  DOM.previewPanel = $("#preview-panel");
  DOM.closeFiltersBtn = $("#close-filters-btn");
  DOM.fulltextToggle = $("#fulltext-toggle");
  DOM.searchPathsToggle = $("#search-paths-toggle");
  DOM.historyToggle = $("#history-toggle");
  DOM.exactToggle = $("#exact-search-toggle");
  DOM.filterSourceList = $("#filter-source-list");
  DOM.filterFolderTree = $("#filter-folder-tree");
  DOM.filterMinSize = $("#filter-min-size");
  DOM.filterMaxSize = $("#filter-max-size");
  DOM.filterMinUnit = $("#filter-min-unit");
  DOM.filterMaxUnit = $("#filter-max-unit");
  DOM.folderSelectAll = $("#folder-select-all");
  DOM.folderDeselectAll = $("#folder-deselect-all");
  DOM.multiToggleLabel = $("#multi-toggle-label");
  DOM.multiSelectToggle = $("#multi-select-toggle");
  DOM.multiActionBar = $("#multi-action-bar");
  DOM.multiSelectAll = $("#multi-select-all");
  DOM.multiDeselect = $("#multi-deselect");
  DOM.multiBatchDownload = $("#multi-batch-download");
  DOM.multiZipDownload = $("#multi-zip-download");
  DOM.multiSelectedCount = $("#multi-selected-count");
  DOM.randomBookBtn = $("#random-book-btn");
  DOM.overlay = $("#overlay");
  DOM.toast = $("#toast");
}

function parseRoute() {
  const path = window.location.pathname.replace(/^\/+|\/+$/g, "");
  if (!path) return { mode: "global", source: null };
  return { mode: "source", source: decodeURIComponent(path) };
}

function syncRoute() {
  const route = parseRoute();
  STATE.mode = route.mode;
  STATE.source = route.source;
  if (STATE.source) {
    DOM.sidebarTitle.textContent = STATE.source;
    if (DOM.sidebarExpandBtn && !STATE.isMobile) DOM.sidebarExpandBtn.style.display = "";
  } else {
    DOM.sidebarTitle.textContent = "数据包";
    if (DOM.sidebarExpandBtn) {
      DOM.sidebarExpandBtn.style.display = "none";
      DOM.leftSidebar.classList.remove("expanded-wide");
      DOM.sidebarExpandBtn.textContent = "↔";
    }
  }
}

function navigateToSource(sourceSlug) {
  history.pushState(null, "", `/${encodeURIComponent(sourceSlug)}`);
  STATE.page = 1;
  STATE.folderSelections = [];
  syncRoute();
  renderSidebar();
  renderFolderTree();
  doSearch();
}

function navigateHome() {
  history.pushState(null, "", "/");
  STATE.page = 1;
  STATE.folderSelections = [];
  syncRoute();
  renderSidebar();
  renderFolderTree();
  doSearch();
}

function getSelectedSourcesForSearch() {
  if (STATE.source) return [STATE.source];
  if (STATE.selectedSources.length) return STATE.selectedSources.slice();
  return [];
}

function updateStatus() {
  DOM.resultCount.textContent = STATE.total ? `共 ${STATE.total.toLocaleString()} 条结果` : "";
  DOM.loadedCount.textContent = STATE.results.length.toLocaleString();
  DOM.totalCount.textContent = STATE.total.toLocaleString();
  DOM.loadInfo.style.display = STATE.total ? "" : "none";
  DOM.multiToggleLabel.style.display = STATE.total ? "" : "none";
  const hasFilter = STATE.folderSelections.length || STATE.selectedSources.length || STATE.minSize !== null || STATE.maxSize !== null;
  DOM.clearFiltersBtn.style.display = hasFilter ? "" : "none";
}

function updateFilterVisibility() {
  const sourceSection = $("#filter-source-section");
  const folderSection = $("#filter-folder-section");
  if (sourceSection) sourceSection.style.display = STATE.source ? "none" : "";
  if (folderSection) folderSection.style.display = STATE.source ? "" : "none";
}

function showToast(message, duration = 2000) {
  DOM.toast.textContent = message;
  DOM.toast.style.display = "";
  clearTimeout(showToast._timer);
  showToast._timer = setTimeout(() => {
    DOM.toast.style.display = "none";
  }, duration);
}

function setHistoryDropdownOpen(open) {
  DOM.searchHistoryDropdown.style.display = open ? "" : "none";
}

function getHistory() {
  try {
    return JSON.parse(localStorage.getItem(HISTORY_KEY)) || [];
  } catch (_error) {
    return [];
  }
}

function saveHistory(items) {
  localStorage.setItem(HISTORY_KEY, JSON.stringify(items.slice(0, 20)));
}

function removeHistory(query) {
  const items = getHistory().filter((item) => item !== query);
  saveHistory(items);
  renderHistoryDropdown();
}

function clearHistory() {
  saveHistory([]);
  renderHistoryDropdown();
}

function addHistory(query) {
  if (!STATE.historyEnabled || !query) return;
  const items = getHistory().filter((item) => item !== query);
  items.unshift(query);
  saveHistory(items);
}

function renderHistoryDropdown() {
  const items = getHistory();
  if (!items.length) {
    setHistoryDropdownOpen(false);
    return;
  }
  DOM.searchHistoryDropdown.innerHTML = items.map((item) => `
    <div class="history-item" data-query="${escapeHTML(item)}">
      <span class="history-text">${escapeHTML(item)}</span>
      <button type="button" class="history-del" data-del="${escapeHTML(item)}" aria-label="删除历史">×</button>
    </div>`).join("") + '<div class="history-footer"><button type="button" class="history-clear-all">清空历史</button></div>';
  setHistoryDropdownOpen(true);
}

function applyTheme() {
  document.body.classList.toggle("light", !STATE.isDark);
}

function applyMobileMode() {
  document.body.classList.toggle("mobile", STATE.isMobile);
  document.body.classList.toggle("force-desktop", !STATE.isMobile);
  if (DOM.mobileToggleIcon) {
    DOM.mobileToggleIcon.className = STATE.isMobile ? "ui-icon ui-icon-desktop" : "ui-icon ui-icon-phone";
  }
  if (DOM.sidebarExpandBtn) {
    DOM.sidebarExpandBtn.style.display = (!STATE.isMobile && STATE.source) ? "" : "none";
    if (STATE.isMobile) {
      DOM.leftSidebar.classList.remove("expanded-wide");
      DOM.sidebarExpandBtn.textContent = "↔";
    }
  }
  if (STATE.isMobile) {
    STATE.leftSidebarOpen = false;
    STATE.rightSidebarOpen = false;
  } else {
    STATE.leftSidebarOpen = true;
    STATE.rightSidebarOpen = false;
  }
  updateSidebarVisibility();
}

function syncUrl(replace = true) {
  const params = new URLSearchParams();
  if (STATE.query) params.set("q", STATE.query);
  if (STATE.selectedSources.length && !STATE.source) {
    for (const slug of STATE.selectedSources) params.append("source", slug);
  }
  if (STATE.folderSelections.length && STATE.source) {
    for (const path of STATE.folderSelections) params.append("folder", path);
  }
  if (STATE.minSize !== null) params.set("min_size", String(STATE.minSize));
  if (STATE.maxSize !== null) params.set("max_size", String(STATE.maxSize));
  if (DOM.sortSelect.value !== "relevance") params.set("sort", DOM.sortSelect.value);
  if (STATE.exact) params.set("exact", "1");
  if (STATE.fulltext) params.set("fulltext", "1");
  if (!STATE.searchPaths) params.set("search_paths", "0");
  if (!STATE.historyEnabled) params.set("history", "0");
  const basePath = STATE.source ? `/${encodeURIComponent(STATE.source)}` : "/";
  const nextUrl = params.toString() ? `${basePath}?${params.toString()}` : basePath;
  if (replace) history.replaceState(null, "", nextUrl);
  else history.pushState(null, "", nextUrl);
}

function loadUrlState() {
  const params = new URLSearchParams(window.location.search);
  STATE.query = params.get("q") || "";
  STATE.selectedSources = params.getAll("source");
  STATE.folderSelections = params.getAll("folder");
  STATE.minSize = params.get("min_size") ? parseInt(params.get("min_size"), 10) : null;
  STATE.maxSize = params.get("max_size") ? parseInt(params.get("max_size"), 10) : null;
  STATE.exact = params.get("exact") === "1";
  STATE.fulltext = params.get("fulltext") === "1";
  STATE.searchPaths = params.get("search_paths") !== "0";
  STATE.historyEnabled = params.get("history") !== "0";
  const sort = params.get("sort") || "relevance";
  DOM.searchInput.value = STATE.query;
  DOM.exactToggle.checked = STATE.exact;
  DOM.fulltextToggle.checked = STATE.fulltext;
  DOM.searchPathsToggle.checked = STATE.searchPaths;
  DOM.historyToggle.checked = STATE.historyEnabled;
  DOM.sortSelect.value = sort;
  if (STATE.minSize !== null) DOM.filterMinSize.value = STATE.minSize;
  if (STATE.maxSize !== null) DOM.filterMaxSize.value = STATE.maxSize;
}

async function ensureFulltextLoaded() {
  if (!STATE.fulltextManifest) {
    STATE.fulltextManifest = await API.fulltextManifest();
  }
  const sourceSlugs = STATE.source ? [STATE.source] : (STATE.selectedSources.length ? STATE.selectedSources : STATE.sources.map((source) => source.slug));
  for (const slug of sourceSlugs) {
    if (STATE.fulltextLoaded[slug]) continue;
    const item = (STATE.fulltextManifest.sources || []).find((source) => source.slug === slug);
    if (!item) continue;
    showToast(`加载全文索引: ${slug}`);
    STATE.fulltextLoaded[slug] = await API.fulltextIndex(item.path);
  }
}

function scoreFulltextDoc(docId, payload, queryTokens, exactQuery) {
  if (exactQuery) {
    const snippet = (payload.snippets[docId] || "").toLowerCase();
    return snippet.includes(exactQuery.toLowerCase()) ? 100 : 1;
  }
  let score = 0;
  for (const token of queryTokens) {
    if ((payload.snippets[docId] || "").toLowerCase().includes(token)) score += 4;
    if ((payload.docs[docId]?.display_name || "").toLowerCase().includes(token)) score += 1;
  }
  return score;
}

async function fulltextSearch() {
  await ensureFulltextLoaded();
  const query = STATE.query.trim();
  const queryTokens = tokenize(query);
  const sourceSlugs = STATE.source ? [STATE.source] : (STATE.selectedSources.length ? STATE.selectedSources : STATE.sources.map((source) => source.slug));
  let results = [];
  for (const slug of sourceSlugs) {
    const payload = STATE.fulltextLoaded[slug];
    if (!payload) continue;
    let matchedIds = null;
    if (STATE.exact) {
      matchedIds = Object.keys(payload.docs).filter((docId) => {
        const snippet = (payload.snippets[docId] || "") + " " + (payload.docs[docId]?.display_name || "");
        return snippet.toLowerCase().includes(query.toLowerCase());
      });
    } else {
      for (const token of queryTokens) {
        const docIds = payload.index[token] || [];
        const set = new Set(docIds);
        if (matchedIds === null) matchedIds = set;
        else matchedIds = new Set(Array.from(matchedIds).filter((docId) => set.has(docId)));
      }
      matchedIds = Array.from(matchedIds || []);
    }
    for (const docId of matchedIds) {
      const meta = payload.docs[docId];
      const folderParts = meta.display_rel_path.split("/");
      const fileName = folderParts.pop();
      const displayName = fileName.replace(/\.txt$/i, "");
      results.push({
        doc_id: docId,
        Source: slug,
        SourceName: STATE.sourceMap[slug]?.name || slug,
        File: displayName,
        Extension: "txt",
        Folder: folderParts,
        DisplayPath: meta.display_rel_path,
        Size: meta.size,
        HasTxt: true,
        snippet: payload.snippets[docId] || "",
        _score: scoreFulltextDoc(docId, payload, queryTokens, query),
      });
    }
  }
  if (STATE.folderSelections.length) {
    results = results.filter((item) => {
      const folder = item.Folder.join("/");
      return STATE.folderSelections.some((selected) => folder === selected || folder.startsWith(selected + "/"));
    });
  }
  if (STATE.minSize !== null) results = results.filter((item) => item.Size >= STATE.minSize);
  if (STATE.maxSize !== null) results = results.filter((item) => item.Size <= STATE.maxSize);
  if (DOM.sortSelect.value === "name") results.sort((a, b) => a.DisplayPath.localeCompare(b.DisplayPath, "zh"));
  else if (DOM.sortSelect.value === "size") results.sort((a, b) => (b.Size - a.Size) || a.DisplayPath.localeCompare(b.DisplayPath, "zh"));
  else results.sort((a, b) => (b._score - a._score) || a.DisplayPath.localeCompare(b.DisplayPath, "zh"));
  const snippetTargets = results.slice(0, STATE.page * STATE.pageSize);
  await Promise.all(snippetTargets.map(async (item) => {
    const data = await API.snippet(item.doc_id, query);
    item.snippet = data && data.snippet ? data.snippet : "";
  }));
  STATE.total = results.length;
  STATE.results = results.slice(0, STATE.page * STATE.pageSize);
}

async function pathSearch() {
  const body = {
    q: STATE.query,
    sources: getSelectedSourcesForSearch(),
    folders: STATE.folderSelections,
    min_size: STATE.minSize,
    max_size: STATE.maxSize,
    page: 1,
    page_size: STATE.page * STATE.pageSize,
    sort: DOM.sortSelect.value,
    exact: STATE.exact,
    search_paths: STATE.searchPaths,
  };
  const data = await API.search(body, STATE.source);
  STATE.total = data.total || 0;
  STATE.results = data.results || [];
}

async function doSearch() {
  STATE.isLoading = true;
  DOM.resultsLoading.style.display = "flex";
  DOM.previewPanel.style.display = "none";
  try {
    if (STATE.fulltext && STATE.query.trim()) {
      await fulltextSearch();
    } else {
      await pathSearch();
    }
    renderResults();
    updateStatus();
  } catch (error) {
    console.error(error);
    showToast("搜索失败");
  } finally {
    STATE.isLoading = false;
    DOM.resultsLoading.style.display = "none";
  }
}

function resultPathHtml(item) {
  const sourcePrefix = `<span class="path-folder" data-source="${escapeHTML(item.Source)}" data-folder="">${highlightText(item.SourceName, STATE.fulltext ? "" : STATE.query)}</span>`;
  const rest = (item.Folder || []).map((part, index) => {
    const path = item.Folder.slice(0, index + 1).join("/");
    return `<span class="path-sep">/</span><span class="path-folder" data-source="${escapeHTML(item.Source)}" data-folder="${escapeHTML(path)}">${highlightText(part, STATE.fulltext ? "" : STATE.query)}</span>`;
  }).join("");
  return sourcePrefix + rest;
}

function renderResults() {
  if (!STATE.results.length) {
    DOM.resultsList.innerHTML = "";
    DOM.emptyState.style.display = "flex";
    DOM.emptyDesc.textContent = STATE.query ? `没有找到与“${STATE.query}”相关的结果` : "暂无数据";
    DOM.multiActionBar.style.display = "none";
    return;
  }
  DOM.emptyState.style.display = "none";
  DOM.resultsList.innerHTML = STATE.results.map((item) => {
    const titleHtml = `${highlightText(item.File, STATE.fulltext ? "" : STATE.query)}<span style="opacity:0.5;font-size:12px">.txt</span>`;
    const snippetHtml = item.snippet ? `<div class="result-snippet">${highlightText(item.snippet, STATE.query)}</div>` : "";
    return `
      <div class="result-item" data-doc-id="${escapeHTML(item.doc_id)}">
        <input type="checkbox" class="result-checkbox" data-doc-id="${escapeHTML(item.doc_id)}" ${STATE.selectedIds.has(item.doc_id) ? "checked" : ""}>
        <div class="result-file-icon">${ICON_HTML.file}</div>
        <div class="result-info">
          <div class="result-title">${titleHtml}</div>
          <div class="result-path">${resultPathHtml(item)}</div>
          <div class="result-meta"><span class="result-size">${escapeHTML(formatSize(item.Size))}</span></div>
          ${snippetHtml}
        </div>
        <div class="result-actions">
          <button class="result-action-btn" data-action="preview" data-doc-id="${escapeHTML(item.doc_id)}">在线预览</button>
          <a class="result-action-btn primary" href="/api/download/${encodeURIComponent(item.doc_id)}">下载</a>
        </div>
      </div>`;
  }).join("");
  DOM.multiActionBar.style.display = STATE.multiSelect ? "" : "none";
}

async function openPreview(docId, keyword) {
  try {
    const data = await API.preview(docId);
    if (data.error) {
      showToast("预览失败");
      return;
    }
    let text = escapeHTML(data.text || "");
    if (keyword) {
      const tokens = tokenize(keyword).filter(Boolean);
      for (const token of tokens) {
        text = text.replace(new RegExp(token.replace(/[.*+?^${}()|[\]\\]/g, "\\$&"), "gi"), (m) => `<mark>${m}</mark>`);
      }
    }
    DOM.previewPanel.innerHTML = `
      <div class="preview-header">
        <div class="preview-title">${escapeHTML(data.title)}</div>
        <div class="preview-path">${escapeHTML(data.source)} / ${escapeHTML(data.path)}</div>
      </div>
      <pre class="preview-body">${text}</pre>`;
    DOM.previewPanel.style.display = "block";
    DOM.previewPanel.scrollIntoView({ behavior: "smooth", block: "start" });
  } catch (error) {
    console.error(error);
    showToast("预览失败");
  }
}

function renderCheckboxList(container, items, selected, onChange) {
  container.innerHTML = items.map((item) => `
    <label class="filter-checkbox-item">
      <input type="checkbox" value="${escapeHTML(item.key)}" ${selected.includes(item.key) ? "checked" : ""}>
      <span>${escapeHTML(item.label)}</span>
      <span class="checkbox-count">${(item.count || 0).toLocaleString()}</span>
    </label>`).join("");
  container.querySelectorAll("input").forEach((input) => {
    input.addEventListener("change", () => {
      const values = Array.from(container.querySelectorAll("input:checked")).map((item) => item.value);
      onChange(values);
    });
  });
}

async function renderSourcesFilter() {
  renderCheckboxList(DOM.filterSourceList, STATE.sources.map((source) => ({ key: source.slug, label: source.name, count: source.count })), STATE.selectedSources, (values) => {
    STATE.selectedSources = values;
    STATE.page = 1;
    syncUrl();
    doSearch();
  });
}

function flattenNodes(nodes, into) {
  for (const node of nodes) {
    if (node.path) into.push(node.path);
    flattenNodes(node.children || [], into);
  }
}

function buildFolderNodeMap(nodes, map = {}) {
  for (const node of nodes) {
    if (node.path) map[node.path] = node;
    buildFolderNodeMap(node.children || [], map);
  }
  return map;
}

function getVisibleFolderNodes(nodes, depth = 0, into = []) {
  for (const node of nodes) {
    into.push({ node, depth });
    if (node.children && node.children.length && !STATE.folderCollapsed[node.path]) {
      getVisibleFolderNodes(node.children, depth + 1, into);
    }
  }
  return into;
}

function collectVisibleDescendantPaths(node, into = []) {
  for (const child of node.children || []) {
    if (!child.path) continue;
    into.push(child.path);
    if (child.children && child.children.length && !STATE.folderCollapsed[child.path]) {
      collectVisibleDescendantPaths(child, into);
    }
  }
  return into;
}

function normalizeFolderTree(nodes) {
  const roots = Array.isArray(nodes) ? nodes : [];
  if (roots.length === 1) {
    const only = roots[0];
    const hasChildren = Array.isArray(only.children) && only.children.length;
    if ((only.isRoot || !only.path || only.path === STATE.source || only.name === STATE.source) && hasChildren) {
      return only.children;
    }
  }
  return roots;
}

function initializeFolderCollapsedState(nodes) {
  const next = {};
  const visit = (items, depth = 0) => {
    for (const node of items) {
      if (node.path && !(node.path in STATE.folderCollapsed)) next[node.path] = depth > 0;
      visit(node.children || [], depth + 1);
    }
  };
  visit(nodes, 0);
  STATE.folderCollapsed = { ...next, ...STATE.folderCollapsed };
}

function isPathCovered(path, selectionSet) {
  if (!path) return false;
  if (selectionSet.has(path)) return true;
  const parts = path.split("/");
  while (parts.length > 1) {
    parts.pop();
    if (selectionSet.has(parts.join("/"))) return true;
  }
  return false;
}

function getFolderSelectionState(node, selectionSet, cache = new Map()) {
  const cacheKey = node.path || `__virtual__:${node.name}:${(node.children || []).length}`;
  if (cache.has(cacheKey)) return cache.get(cacheKey);
  let state = "unchecked";
  if (node.path && isPathCovered(node.path, selectionSet)) {
    state = "checked";
  } else {
    const children = node.children || [];
    if (children.length) {
      const childStates = children.map((child) => getFolderSelectionState(child, selectionSet, cache));
      if (childStates.every((item) => item === "checked")) state = "checked";
      else if (childStates.some((item) => item !== "unchecked")) state = "indeterminate";
    }
  }
  cache.set(cacheKey, state);
  return state;
}

function normalizeFolderSelections(selections) {
  const unique = Array.from(new Set((selections || []).filter(Boolean)));
  return unique.filter((path) => !unique.some((other) => other !== path && path.startsWith(other + "/")));
}

function selectFolderPath(path) {
  const selectionSet = new Set(normalizeFolderSelections(STATE.folderSelections));
  if (isPathCovered(path, selectionSet)) return Array.from(selectionSet);
  const next = Array.from(selectionSet).filter((item) => !(item === path || item.startsWith(path + "/")));
  next.push(path);
  return normalizeFolderSelections(next);
}

function collectSelectionsExcept(node, excludedPath, into) {
  if (!node.path) {
    for (const child of node.children || []) collectSelectionsExcept(child, excludedPath, into);
    return;
  }
  if (node.path === excludedPath || excludedPath.startsWith(node.path + "/")) {
    for (const child of node.children || []) collectSelectionsExcept(child, excludedPath, into);
    return;
  }
  into.push(node.path);
}

function deselectFolderPath(path) {
  let next = normalizeFolderSelections(STATE.folderSelections).filter((item) => !(item === path || item.startsWith(path + "/")));
  const parts = path.split("/");
  while (parts.length > 1) {
    parts.pop();
    const ancestorPath = parts.join("/");
    const ancestorIndex = next.indexOf(ancestorPath);
    if (ancestorIndex === -1) continue;
    next.splice(ancestorIndex, 1);
    const ancestorNode = STATE.folderNodeMap[ancestorPath];
    if (ancestorNode) {
      const expanded = [];
      collectSelectionsExcept(ancestorNode, path, expanded);
      next.push(...expanded);
    }
    break;
  }
  return normalizeFolderSelections(next);
}

function invertFolderSelections() {
  const selectionSet = new Set(normalizeFolderSelections(STATE.folderSelections));
  const stateCache = new Map();
  const next = [];
  const invertNode = (node) => {
    const state = getFolderSelectionState(node, selectionSet, stateCache);
    if (state === "checked") return;
    if (state === "unchecked") {
      if (node.path) next.push(node.path);
      else for (const child of node.children || []) invertNode(child);
      return;
    }
    for (const child of node.children || []) invertNode(child);
  };
  for (const node of STATE.folderTree) invertNode(node);
  return normalizeFolderSelections(next);
}

function refreshFolderTreeSelectionState() {
  if (!DOM.filterFolderTree) return;
  const selectionSet = new Set(normalizeFolderSelections(STATE.folderSelections));
  const stateCache = new Map();
  DOM.filterFolderTree.querySelectorAll("input[data-folder-path]").forEach((checkbox) => {
    const node = STATE.folderNodeMap[checkbox.dataset.folderPath];
    if (!node) return;
    const state = getFolderSelectionState(node, selectionSet, stateCache);
    checkbox.checked = state === "checked";
    checkbox.indeterminate = state === "indeterminate";
  });
  DOM.filterFolderTree.querySelectorAll(".tree-toggle[data-folder-path]").forEach((toggle) => {
    const path = toggle.dataset.folderPath;
    const collapsed = !!STATE.folderCollapsed[path];
    toggle.classList.toggle("expanded", !collapsed);
    toggle.setAttribute("aria-label", collapsed ? "展开子文件夹" : "收起子文件夹");
    toggle.setAttribute("title", collapsed ? "展开" : "收起");
  });
}

function applyFolderSelections(nextSelections) {
  STATE.folderSelections = normalizeFolderSelections(nextSelections);
  STATE.page = 1;
  refreshFolderTreeSelectionState();
  syncUrl();
  doSearch();
}

function renderFolderTreeRows(animation = {}) {
  const container = DOM.filterFolderTree;
  if (!container) return;
  const firstRects = new Map();
  container.querySelectorAll(".filter-folder-item[data-folder-path]").forEach((row) => {
    firstRects.set(row.dataset.folderPath, row.getBoundingClientRect());
  });
  container.innerHTML = "";
  renderFolderNodes(container, STATE.folderTree, 0);
  refreshFolderTreeSelectionState();
  const newRows = container.querySelectorAll(".filter-folder-item[data-folder-path]");
  newRows.forEach((row) => {
    const path = row.dataset.folderPath;
    const lastRect = row.getBoundingClientRect();
    const firstRect = firstRects.get(path);
    if (firstRect) {
      const deltaY = firstRect.top - lastRect.top;
      if (Math.abs(deltaY) > 0.5) {
        row.animate([
          { transform: `translateY(${deltaY}px)` },
          { transform: "translateY(0)" },
        ], {
          duration: 220,
          easing: "ease",
        });
      }
    } else {
      row.animate([
        { opacity: 0, transform: "translateY(-8px)" },
        { opacity: 1, transform: "translateY(0)" },
      ], {
        duration: 220,
        easing: "ease",
      });
    }
    if (animation.expanding && animation.toggledPath && row.dataset.folderPath === animation.toggledPath) {
      const glyph = row.querySelector(".tree-toggle-glyph");
      if (glyph) {
        const fromTransform = "rotate(-45deg)";
        const toTransform = "rotate(45deg)";
        glyph.animate([
          { transform: fromTransform },
          { transform: toTransform },
        ], {
          duration: 220,
          easing: "ease",
        });
      }
    }
  });
}

function animateFolderCollapse(nodePath, exitingPaths) {
  const container = DOM.filterFolderTree;
  if (!container) return 200;
  const duration = 200;
  const glyph = container.querySelector(`.filter-folder-item[data-folder-path="${CSS.escape(nodePath)}"] .tree-toggle-glyph`);
  if (glyph) {
    glyph.animate([
      { transform: "rotate(45deg)" },
      { transform: "rotate(-45deg)" },
    ], {
      duration: 220,
      easing: "ease",
      fill: "forwards",
    });
  }
  for (const path of exitingPaths) {
    const row = container.querySelector(`.filter-folder-item[data-folder-path="${CSS.escape(path)}"]`);
    if (!row) continue;
    row.animate([
      { opacity: 1, transform: "translateY(0) scaleY(1)" },
      { opacity: 0, transform: "translateY(-10px) scaleY(0.96)" },
    ], {
      duration,
      easing: "ease",
      fill: "forwards",
    });
  }
  return duration;
}

function renderFolderNodes(container, nodes, depth) {
  const visibleNodes = getVisibleFolderNodes(nodes, depth);
  for (const { node, depth: itemDepth } of visibleNodes) {
    const hasChildren = !!(node.children && node.children.length);
    const row = document.createElement("div");
    row.className = "filter-folder-item";
    row.dataset.folderPath = node.path;
    row.style.setProperty("--fdepth", itemDepth);
    row.innerHTML = `${hasChildren ? `<button type="button" class="tree-toggle" data-folder-path="${escapeHTML(node.path)}" aria-label="展开子文件夹" title="展开"><span class="tree-toggle-glyph" aria-hidden="true"></span></button>` : '<span class="tree-toggle-placeholder"></span>'}<input type="checkbox" data-folder-path="${escapeHTML(node.path)}" value="${escapeHTML(node.path)}"><span class="folder-name">${escapeHTML(node.name)}</span><span class="folder-count">${(node.count || 0).toLocaleString()}</span>`;
    const toggle = row.querySelector(".tree-toggle");
    if (toggle) {
      toggle.addEventListener("click", (event) => {
        event.stopPropagation();
        const expanding = !!STATE.folderCollapsed[node.path];
        if (expanding) {
          STATE.folderCollapsed[node.path] = false;
          renderFolderTreeRows({ toggledPath: node.path, expanding: true });
          return;
        }
        const exitingPaths = collectVisibleDescendantPaths(node);
        const duration = animateFolderCollapse(node.path, exitingPaths);
        STATE.folderCollapsed[node.path] = true;
        window.setTimeout(() => {
          renderFolderTreeRows({ toggledPath: node.path, expanding: false });
        }, duration);
      });
    }
    const checkbox = row.querySelector("input");
    checkbox.addEventListener("change", () => {
      const selectionSet = new Set(normalizeFolderSelections(STATE.folderSelections));
      const state = getFolderSelectionState(node, selectionSet);
      if (state === "checked") applyFolderSelections(deselectFolderPath(node.path));
      else applyFolderSelections(selectFolderPath(node.path));
    });
    container.appendChild(row);
  }
}

async function renderFolderTree(forceReload = false) {
  updateFilterVisibility();
  if (!STATE.source) {
    DOM.filterFolderTree.innerHTML = '<div style="font-size:12px;opacity:0.6">进入单仓库后可按路径过滤</div>';
    STATE.folderTree = [];
    STATE.folderTreeSource = null;
    STATE.folderNodeMap = {};
    return;
  }
  if (forceReload || STATE.folderTreeSource !== STATE.source || !STATE.folderTree.length) {
    STATE.folderTree = normalizeFolderTree(await API.getFolders(STATE.source));
    STATE.folderTreeSource = STATE.source;
    STATE.folderNodeMap = buildFolderNodeMap(STATE.folderTree);
    STATE.folderCollapsed = {};
    initializeFolderCollapsedState(STATE.folderTree);
    renderFolderTreeRows();
  }
  refreshFolderTreeSelectionState();
}

async function renderSidebar() {
  if (!STATE.source) {
    DOM.sidebarTitle.textContent = "数据包";
    DOM.sidebarContent.innerHTML = STATE.sources.map((source) => `<div class="repo-list-item" data-source="${escapeHTML(source.slug)}">${ICON_HTML.source}<span class="repo-name">${escapeHTML(source.name)}</span><span class="repo-count">${(source.count || 0).toLocaleString()}</span></div>`).join("");
    return;
  }
  DOM.sidebarTitle.textContent = STATE.sourceMap[STATE.source]?.name || STATE.source;
  const data = await API.getContents(STATE.source, "");
  let html = '<div class="back-to-global" id="back-home">返回全局搜索</div>';
  html += (data.folders || []).map((item) => `<div class="browser-item" data-folder-open="${escapeHTML(item.path)}">${ICON_HTML.folder}<span class="browser-name">${escapeHTML(item.name)}</span><span class="browser-count">${(item.count || 0).toLocaleString()}</span></div>`).join("");
  html += (data.files || []).map((item) => `<div class="browser-item" data-doc-id="${escapeHTML(item.doc_id)}">${ICON_HTML.file}<span class="browser-name">${escapeHTML(item.name)}.txt</span><span class="browser-size">${escapeHTML(formatSize(item.size))}</span></div>`).join("");
  DOM.sidebarContent.innerHTML = html;
}

async function openFolder(path) {
  const data = await API.getContents(STATE.source, path);
  const parts = path ? path.split("/") : [];
  let html = '<div class="back-to-global" id="back-home">返回全局搜索</div>';
  html += `<div class="sidebar-breadcrumb"><span class="crumb-item" data-folder-nav="">根目录</span>${parts.map((part, index) => `<span class="crumb-sep">/</span><span class="crumb-item" data-folder-nav="${escapeHTML(parts.slice(0, index + 1).join("/"))}">${escapeHTML(part)}</span>`).join("")}</div>`;
  html += (data.folders || []).map((item) => `<div class="browser-item" data-folder-open="${escapeHTML(item.path)}">${ICON_HTML.folder}<span class="browser-name">${escapeHTML(item.name)}</span><span class="browser-count">${(item.count || 0).toLocaleString()}</span></div>`).join("");
  html += (data.files || []).map((item) => `<div class="browser-item" data-doc-id="${escapeHTML(item.doc_id)}">${ICON_HTML.file}<span class="browser-name">${escapeHTML(item.name)}.txt</span><span class="browser-size">${escapeHTML(formatSize(item.size))}</span></div>`).join("");
  DOM.sidebarContent.innerHTML = html;
}

function updateSidebarVisibility() {
  DOM.leftSidebar.classList.toggle("collapsed", !STATE.leftSidebarOpen);
  DOM.rightSidebar.classList.toggle("collapsed", !STATE.rightSidebarOpen);
  DOM.leftSidebar.classList.toggle("open", STATE.leftSidebarOpen);
  DOM.rightSidebar.classList.toggle("open", STATE.rightSidebarOpen);
  DOM.overlay.style.display = (STATE.isMobile && (STATE.leftSidebarOpen || STATE.rightSidebarOpen)) ? "" : "none";
}

function clearFilters() {
  STATE.folderSelections = [];
  STATE.selectedSources = [];
  STATE.minSize = null;
  STATE.maxSize = null;
  DOM.filterMinSize.value = "";
  DOM.filterMaxSize.value = "";
  DOM.filterMinUnit.value = "MB";
  DOM.filterMaxUnit.value = "MB";
  renderSourcesFilter();
  refreshFolderTreeSelectionState();
  syncUrl();
  doSearch();
}

async function randomDoc() {
  const data = await API.random(STATE.source);
  if (!data.doc_id) {
    showToast("暂无可用文档");
    return;
  }
  openPreview(data.doc_id, "");
}

function updateMultiUi() {
  STATE.multiSelect = DOM.multiSelectToggle.checked;
  DOM.multiActionBar.style.display = STATE.multiSelect ? "" : "none";
  document.body.classList.toggle("multiselect", STATE.multiSelect);
  if (!STATE.multiSelect) STATE.selectedIds.clear();
  DOM.multiSelectedCount.textContent = STATE.selectedIds.size ? `已选 ${STATE.selectedIds.size} 项` : "";
  renderResults();
}

function attachEvents() {
  DOM.headerLogo.addEventListener("click", (event) => {
    if (window.location.pathname !== "/") return;
    event.preventDefault();
    window.location.href = DOM.headerLogo.href;
  });
  DOM.hamburgerBtn.addEventListener("click", () => {
    STATE.leftSidebarOpen = !STATE.leftSidebarOpen;
    if (STATE.isMobile && STATE.leftSidebarOpen) STATE.rightSidebarOpen = false;
    updateSidebarVisibility();
  });
  if (DOM.sidebarExpandBtn) {
    DOM.sidebarExpandBtn.addEventListener("click", () => {
      DOM.leftSidebar.classList.toggle("expanded-wide");
      DOM.sidebarExpandBtn.textContent = DOM.leftSidebar.classList.contains("expanded-wide") ? "→" : "↔";
    });
  }
  DOM.settingsBtn.addEventListener("click", () => {
    STATE.rightSidebarOpen = !STATE.rightSidebarOpen;
    if (STATE.isMobile && STATE.rightSidebarOpen) STATE.leftSidebarOpen = false;
    updateSidebarVisibility();
  });
  DOM.closeFiltersBtn.addEventListener("click", () => {
    STATE.rightSidebarOpen = false;
    updateSidebarVisibility();
  });
  DOM.overlay.addEventListener("click", () => {
    STATE.leftSidebarOpen = false;
    STATE.rightSidebarOpen = false;
    updateSidebarVisibility();
  });
  DOM.themeBtn.addEventListener("click", () => {
    STATE.isDark = !STATE.isDark;
    applyTheme();
    localStorage.setItem("theme", STATE.isDark ? "dark" : "light");
  });
  DOM.mobileToggleBtn.addEventListener("click", () => {
    STATE.isMobile = !STATE.isMobile;
    applyMobileMode();
  });
  let historyDropdownActive = false;
  DOM.searchInput.addEventListener("focus", renderHistoryDropdown);
  DOM.searchInput.addEventListener("blur", () => setTimeout(() => { if (!historyDropdownActive) setHistoryDropdownOpen(false); }, 120));
  DOM.searchHistoryDropdown.addEventListener("mouseenter", () => { historyDropdownActive = true; });
  DOM.searchHistoryDropdown.addEventListener("mouseleave", () => { historyDropdownActive = false; });
  DOM.searchHistoryDropdown.addEventListener("click", (event) => {
    const delBtn = event.target.closest(".history-del");
    if (delBtn) {
      event.stopPropagation();
      removeHistory(delBtn.dataset.del);
      historyDropdownActive = true;
      DOM.searchInput.focus();
      return;
    }
    const clearBtn = event.target.closest(".history-clear-all");
    if (clearBtn) {
      clearHistory();
      historyDropdownActive = true;
      DOM.searchInput.focus();
      return;
    }
    const item = event.target.closest("[data-query]");
    if (!item) return;
    DOM.searchInput.value = item.dataset.query;
    STATE.query = item.dataset.query;
    syncUrl();
    doSearch();
  });
  let historyLongPressTimer = null;
  const cancelHistoryLongPress = () => {
    if (historyLongPressTimer) {
      clearTimeout(historyLongPressTimer);
      historyLongPressTimer = null;
    }
  };
  DOM.searchHistoryDropdown.addEventListener("mousedown", (event) => {
    const item = event.target.closest("[data-query]");
    if (!item || event.target.closest(".history-del") || event.target.closest(".history-clear-all")) return;
    cancelHistoryLongPress();
    historyLongPressTimer = setTimeout(() => {
      removeHistory(item.dataset.query);
      historyLongPressTimer = null;
    }, 600);
  });
  DOM.searchHistoryDropdown.addEventListener("mouseup", cancelHistoryLongPress);
  DOM.searchHistoryDropdown.addEventListener("mouseleave", cancelHistoryLongPress);
  DOM.searchHistoryDropdown.addEventListener("touchstart", (event) => {
    const item = event.target.closest("[data-query]");
    if (!item || event.target.closest(".history-del") || event.target.closest(".history-clear-all")) return;
    cancelHistoryLongPress();
    historyLongPressTimer = setTimeout(() => {
      removeHistory(item.dataset.query);
      historyLongPressTimer = null;
    }, 650);
  }, { passive: true });
  DOM.searchHistoryDropdown.addEventListener("touchend", cancelHistoryLongPress, { passive: true });
  DOM.searchHistoryDropdown.addEventListener("touchmove", cancelHistoryLongPress, { passive: true });
  let timer = null;
  DOM.searchInput.addEventListener("input", () => {
    clearTimeout(timer);
    timer = setTimeout(() => {
      STATE.query = DOM.searchInput.value.trim();
      STATE.page = 1;
      addHistory(STATE.query);
      renderHistoryDropdown();
      syncUrl();
      doSearch();
    }, 250);
  });
  DOM.sortSelect.addEventListener("change", () => {
    STATE.page = 1;
    syncUrl();
    doSearch();
  });
  DOM.exactToggle.addEventListener("change", () => {
    STATE.exact = DOM.exactToggle.checked;
    STATE.page = 1;
    syncUrl();
    doSearch();
  });
  DOM.historyToggle.addEventListener("change", () => {
    STATE.historyEnabled = DOM.historyToggle.checked;
    if (!STATE.historyEnabled) saveHistory([]);
    syncUrl();
  });
  DOM.fulltextToggle.addEventListener("change", async () => {
    STATE.fulltext = DOM.fulltextToggle.checked;
    if (DOM.searchPathsToggle) {
      DOM.searchPathsToggle.disabled = STATE.fulltext;
      if (STATE.fulltext) DOM.searchPathsToggle.closest(".toggle-row").style.opacity = "0.5";
      else DOM.searchPathsToggle.closest(".toggle-row").style.opacity = "";
    }
    DOM.searchInput.placeholder = STATE.fulltext ? "全文搜索 TXT 正文..." : "搜索 TXT 文件或路径...";
    STATE.page = 1;
    if (STATE.fulltext) await ensureFulltextLoaded();
    syncUrl();
    doSearch();
  });
  DOM.searchPathsToggle.addEventListener("change", () => {
    STATE.searchPaths = DOM.searchPathsToggle.checked;
    STATE.page = 1;
    syncUrl();
    doSearch();
  });
  DOM.clearFiltersBtn.addEventListener("click", clearFilters);
  DOM.emptyRandomBtn.addEventListener("click", randomDoc);
  if (DOM.randomBookBtn) DOM.randomBookBtn.addEventListener("click", randomDoc);
  DOM.filterMinSize.addEventListener("input", () => {
    STATE.minSize = bytesFromInput(DOM.filterMinSize.value, DOM.filterMinUnit.value);
    syncUrl();
    doSearch();
  });
  DOM.filterMaxSize.addEventListener("input", () => {
    STATE.maxSize = bytesFromInput(DOM.filterMaxSize.value, DOM.filterMaxUnit.value);
    syncUrl();
    doSearch();
  });
  DOM.filterMinUnit.addEventListener("change", () => {
    STATE.minSize = bytesFromInput(DOM.filterMinSize.value, DOM.filterMinUnit.value);
    syncUrl();
    doSearch();
  });
  DOM.filterMaxUnit.addEventListener("change", () => {
    STATE.maxSize = bytesFromInput(DOM.filterMaxSize.value, DOM.filterMaxUnit.value);
    syncUrl();
    doSearch();
  });
  DOM.folderSelectAll.addEventListener("click", () => {
    const paths = [];
    flattenNodes(STATE.folderTree, paths);
    applyFolderSelections(paths);
  });
  DOM.folderDeselectAll.addEventListener("click", () => {
    applyFolderSelections(invertFolderSelections());
  });
  DOM.multiSelectToggle.addEventListener("change", updateMultiUi);
  DOM.multiSelectAll.addEventListener("click", () => {
    STATE.selectedIds = new Set(STATE.results.map((item) => item.doc_id));
    updateMultiUi();
  });
  DOM.multiDeselect.addEventListener("click", () => {
    STATE.selectedIds.clear();
    updateMultiUi();
  });
  DOM.multiBatchDownload.addEventListener("click", () => {
    const ids = Array.from(STATE.selectedIds);
    if (!ids.length) {
      showToast("未选中任何文件");
      return;
    }
    ids.forEach((id, index) => setTimeout(() => { window.open(`/api/download/${encodeURIComponent(id)}`, "_blank"); }, index * 250));
  });
  DOM.multiZipDownload.addEventListener("click", async () => {
    const ids = Array.from(STATE.selectedIds);
    if (!ids.length) {
      showToast("未选中任何文件");
      return;
    }
    showToast(`正在打包 ${ids.length} 个文件...`, 2500);
    try {
      const resp = await fetch("/api/zip", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ doc_ids: ids }),
      });
      if (!resp.ok) {
        let message = `HTTP ${resp.status}`;
        try {
          const data = await resp.json();
          if (data && data.error) message = data.error;
        } catch (_error) {}
        throw new Error(message);
      }
      const blob = await resp.blob();
      const link = document.createElement("a");
      const objectUrl = URL.createObjectURL(blob);
      link.href = objectUrl;
      link.download = `vomebook_batch_${Date.now()}.zip`;
      link.style.display = "none";
      document.body.appendChild(link);
      link.click();
      link.remove();
      setTimeout(() => URL.revokeObjectURL(objectUrl), 1000);
      showToast(`已开始下载 ${ids.length} 个文件的压缩包`);
    } catch (error) {
      console.error(error);
      showToast(`合并下载失败: ${error.message || '未知错误'}`, 3500);
    }
  });
  DOM.resultsList.addEventListener("click", async (event) => {
    const checkbox = event.target.closest(".result-checkbox");
    if (checkbox) {
      const docId = checkbox.dataset.docId;
      if (checkbox.checked) STATE.selectedIds.add(docId);
      else STATE.selectedIds.delete(docId);
      DOM.multiSelectedCount.textContent = STATE.selectedIds.size ? `已选 ${STATE.selectedIds.size} 项` : "";
      return;
    }
    const action = event.target.closest("[data-action='preview']");
    if (action) {
      event.preventDefault();
      openPreview(action.dataset.docId, STATE.query);
      return;
    }
    const folder = event.target.closest(".path-folder[data-folder]");
    if (folder) {
      const source = folder.dataset.source;
      const path = folder.dataset.folder;
      if (STATE.mode === "global" && source && !STATE.source) {
        navigateToSource(source);
        if (path) STATE.folderSelections = [path];
      } else {
        STATE.folderSelections = path ? [path] : [];
      }
      refreshFolderTreeSelectionState();
      syncUrl();
      doSearch();
    }
  });
  DOM.sidebarContent.addEventListener("click", async (event) => {
    const sourceItem = event.target.closest("[data-source]");
    if (sourceItem) {
      navigateToSource(sourceItem.dataset.source);
      return;
    }
    const backHome = event.target.closest("#back-home");
    if (backHome) {
      navigateHome();
      return;
    }
    const folderOpen = event.target.closest("[data-folder-open]");
    if (folderOpen) {
      openFolder(folderOpen.dataset.folderOpen);
      return;
    }
    const folderNav = event.target.closest("[data-folder-nav]");
    if (folderNav) {
      openFolder(folderNav.dataset.folderNav);
      return;
    }
    const docItem = event.target.closest("[data-doc-id]");
    if (docItem) {
      openPreview(docItem.dataset.docId, STATE.query);
    }
  });
  DOM.resultsContainer.addEventListener("scroll", () => {
    const nearBottom = DOM.resultsContainer.scrollTop + DOM.resultsContainer.clientHeight >= DOM.resultsContainer.scrollHeight - 200;
    if (nearBottom && STATE.results.length < STATE.total && !STATE.isLoading) {
      STATE.page += 1;
      doSearch();
    }
  });
  document.addEventListener("keydown", (event) => {
    if (event.key === "/" && document.activeElement !== DOM.searchInput) {
      event.preventDefault();
      DOM.searchInput.focus();
      DOM.searchInput.select();
    }
  });
  window.addEventListener("popstate", async () => {
    syncRoute();
    await renderSidebar();
    await renderFolderTree();
    doSearch();
  });
}

async function init() {
  cacheDom();
  STATE.isDark = localStorage.getItem("theme") !== "light";
  applyTheme();
  STATE.isMobile = window.innerWidth <= 768;
  syncRoute();
  loadUrlState();
  applyMobileMode();
  STATE.sources = await API.getSources();
  STATE.sourceMap = Object.fromEntries(STATE.sources.map((source) => [source.slug, source]));
  await renderSourcesFilter();
  await renderSidebar();
  await renderFolderTree();
  updateFilterVisibility();
  attachEvents();
  if (DOM.searchPathsToggle) {
    DOM.searchPathsToggle.checked = STATE.searchPaths;
    DOM.searchPathsToggle.disabled = STATE.fulltext;
    DOM.searchPathsToggle.closest(".toggle-row").style.opacity = STATE.fulltext ? "0.5" : "";
  }
  updateSidebarVisibility();
  syncUrl();
  doSearch();
}

document.addEventListener("DOMContentLoaded", init);