const Library = (() => {
  let dirty = true;
  let sortMode = localStorage.getItem('libSortMode') || 'added';
  let shelves = [];
  let libraryTags = [];
  let selectedShelf = '';
  let selectedTag = '';
  let searchQuery = '';
  let refreshSeq = 0;
  let grid, statusEl;
  let selectMode = false;
  const selectedIds = new Set();
  let visibleIds = [];

  // 必须与 main.js 的 READABLE_EXT 保持一致。漏掉格式不会报错，
  // 只是「阅读」按钮和封面点击静默消失，看上去像阅读器打不开这类文件
  const READABLE_RE = /\.(pdf|epub|mobi|azw|azw3|txt|md)$/i;
  const isReadableFile = (file) => !!file && file.exists
    && READABLE_RE.test(file.path || file.name || '');

  const SORTERS = {
    recent: (a, b) => (
      (b.lastReadAt || 0) - (a.lastReadAt || 0)
      || (b.addedAt || 0) - (a.addedAt || 0)
    ),
    added: (a, b) => (b.addedAt || 0) - (a.addedAt || 0),
    title: (a, b) => String(a.title).localeCompare(String(b.title), 'zh'),
    author: (a, b) => String((a.authors || [])[0] || '').localeCompare(String((b.authors || [])[0] || ''), 'zh')
  };
  const CARD_ICONS = {
    read: '<path d="M4 5.5A2.5 2.5 0 0 1 6.5 3H11v16H6.5A2.5 2.5 0 0 0 4 21.5Z"/><path d="M20 5.5A2.5 2.5 0 0 0 17.5 3H13v16h4.5a2.5 2.5 0 0 1 2.5 2.5Z"/>',
    open: '<path d="M4 7h6l2 2h8v10H4Z"/><path d="m13 14 3-3 3 3M16 11v6"/>',
    reveal: '<path d="M4 6h6l2 2h8v11H4Z"/><circle cx="15" cy="13" r="2.5"/><path d="m17 15 2 2"/>',
    page: '<path d="M10 13a5 5 0 0 0 7.5.5l2-2a5 5 0 0 0-7-7l-1.2 1.2"/><path d="M14 11a5 5 0 0 0-7.5-.5l-2 2a5 5 0 0 0 7 7l1.2-1.2"/>',
    organize: '<path d="M3 5v6l8 8 8-8-8-8H5a2 2 0 0 0-2 2Z"/><circle cx="8" cy="8" r="1"/>',
    remove: '<path d="M4 7h16M9 7V4h6v3M7 7l1 13h8l1-13M10 11v5M14 11v5"/>'
  };

  function cardAction(action, label, primary = false, disabled = false) {
    return `<button class="${primary ? 'open-btn ' : ''}icon-action"
      data-act="${action}" title="${label}" aria-label="${label}" ${disabled ? 'disabled' : ''}>
      <svg viewBox="0 0 24 24" aria-hidden="true">${CARD_ICONS[action]}</svg>
    </button>`;
  }

  function init() {
    grid = $('libGrid');
    statusEl = $('libStatus');
    $('addLocalBtn').onclick = addLocal;
    $('rescanBtn').onclick = rescan;
    $('addShelfBtn').onclick = addShelf;
    $('addTagBtn').onclick = addTag;
    $('librarySearchBtn').onclick = applySearch;
    $('libraryClearSearchBtn').onclick = clearSearch;
    $('librarySearchInput').onkeydown = (event) => {
      if (event.key === 'Enter') applySearch();
    };
    $('librarySearchInput').onsearch = () => {
      if (!$('librarySearchInput').value) clearSearch();
    };
    document.querySelectorAll('#libraryTab .library-filter[data-shelf]').forEach((button) => {
      button.onclick = () => selectShelf(button.dataset.shelf || '');
    });
    $('librarySelectModeBtn').onclick = () => setSelectMode(!selectMode);
    $('librarySelectExitBtn').onclick = () => setSelectMode(false);
    $('librarySelectAll').onchange = (event) => {
      if (event.target.checked) visibleIds.forEach((id) => selectedIds.add(id));
      else selectedIds.clear();
      syncSelectionUi();
    };
    $('libraryBulkOrganizeBtn').onclick = bulkOrganize;
    $('libraryBulkRemoveBtn').onclick = bulkRemove;
    window.api.library.onChanged(() => { dirty = true; refresh(true); });
    if (window.api.reader && window.api.reader.onNotesChanged) {
      window.api.reader.onNotesChanged(() => {
        dirty = true;
        if (!$('libraryTab').classList.contains('hidden')) refresh(true);
      });
    }
  }

  async function rescan() {
    const btn = $('rescanBtn');
    btn.disabled = true;
    btn.textContent = '扫描中...';
    const r = await window.api.library.scan();
    btn.textContent = r.ok && r.data && r.data.added ? `新增 ${r.data.added} 本 ✓` : '已是最新 ✓';
    dirty = true;
    await refresh(true);
    setTimeout(() => { btn.textContent = '重新扫描'; btn.disabled = false; }, 2000);
  }

  function getSortMode() { return sortMode; }
  function setSortMode(m) {
    sortMode = m;
    localStorage.setItem('libSortMode', m);
    dirty = true;
    refresh(true);
  }

  function noteCountsOf(result) {
    const counts = new Map();
    if (!result || !result.ok || !result.data) return counts;
    let data = result.data.counts || result.data;
    if (Array.isArray(data)) {
      data.forEach((item) => {
        if (Array.isArray(item)) {
          counts.set(String(item[0]), Math.max(0, Math.floor(Number(item[1]) || 0)));
        } else if (item && (item.entryId != null || item.id != null)) {
          const entryId = item.entryId == null ? item.id : item.entryId;
          const count = item.count == null ? item.noteCount : item.count;
          counts.set(String(entryId), Math.max(0, Math.floor(Number(count) || 0)));
        }
      });
      return counts;
    }
    if (data && typeof data === 'object') {
      Object.entries(data).forEach(([entryId, count]) => {
        if (count && typeof count === 'object') count = count.count == null ? count.noteCount : count.count;
        counts.set(String(entryId), Math.max(0, Math.floor(Number(count) || 0)));
      });
    }
    return counts;
  }

  function normalizedSearch(value) {
    return String(value || '')
      .normalize('NFKC')
      .toLocaleLowerCase()
      .replace(/\s+/g, ' ')
      .trim();
  }

  function isSubsequence(needle, haystack) {
    if (!needle || !haystack) return false;
    let offset = 0;
    for (const character of needle) {
      offset = haystack.indexOf(character, offset);
      if (offset < 0) return false;
      offset++;
    }
    return true;
  }

  function matchesSearch(item, query) {
    const normalized = normalizedSearch(query);
    if (!normalized) return true;
    const title = normalizedSearch(item.title);
    const authors = normalizedSearch((item.authors || []).join(' '));
    const combined = `${title} ${authors}`.trim();
    return normalized.split(' ').every((token) => (
      title.includes(token)
      || authors.includes(token)
      || (token.length > 1 && isSubsequence(token, combined))
    ));
  }

  function applySearch() {
    searchQuery = $('librarySearchInput').value.trim();
    $('libraryClearSearchBtn').classList.toggle('hidden', !searchQuery);
    dirty = true;
    refresh(true);
  }

  function clearSearch() {
    searchQuery = '';
    $('librarySearchInput').value = '';
    $('libraryClearSearchBtn').classList.add('hidden');
    dirty = true;
    refresh(true);
  }

  function setSelectMode(on) {
    selectMode = !!on;
    if (!selectMode) selectedIds.clear();
    $('libraryTab').classList.toggle('select-mode', selectMode);
    $('librarySelectionBar').classList.toggle('hidden', !selectMode);
    const toggle = $('librarySelectModeBtn');
    toggle.classList.toggle('active', selectMode);
    toggle.setAttribute('aria-pressed', String(selectMode));
    dirty = true;
    refresh(true);
  }

  function syncSelectionUi() {
    if (!selectMode) return;
    const total = visibleIds.length;
    const picked = visibleIds.filter((id) => selectedIds.has(id)).length;
    const all = $('librarySelectAll');
    all.checked = total > 0 && picked === total;
    all.indeterminate = picked > 0 && picked < total;
    all.disabled = total === 0;
    $('librarySelectAllLabel').textContent = all.checked ? '取消全选' : '全选';
    $('librarySelectionCount').textContent = picked
      ? `已选择 ${picked} 项${picked === total ? '（当前全部）' : ''}`
      : '未选择';
    $('libraryBulkOrganizeBtn').disabled = !picked;
    $('libraryBulkRemoveBtn').disabled = !picked;
    grid.querySelectorAll(':scope > .card').forEach((card) => {
      const on = selectedIds.has(card.dataset.id);
      card.classList.toggle('selected', on);
      const box = card.querySelector('.card-select input');
      if (box) box.checked = on;
    });
  }

  function toggleSelection(id, on) {
    if (on === undefined) on = !selectedIds.has(id);
    if (on) selectedIds.add(id);
    else selectedIds.delete(id);
    syncSelectionUi();
  }

  function selectedEntries(items) {
    return items.filter((item) => selectedIds.has(String(item.id)));
  }

  function cardHtml(it, noteCounts, annotationCounts) {
    const openable = (it.files || []).some((file) => file.exists);
    const readable = (it.files || []).some(isReadableFile);
    const badge = openable
      ? '<span class="card-badge">已下载</span>'
      : ((it.files || []).length
        ? '<span class="card-badge miss">文件缺失</span>'
        : '<span class="card-badge miss">未下载</span>');
    const noteCount = noteCounts.get(String(it.id)) || 0;
    const noteBadge = noteCount > 0
      ? `<span class="card-badge note-count">笔记 ${noteCount}</span>`
      : '';
    const annotationCount = annotationCounts.get(String(it.id)) || 0;
    const annotationBadge = annotationCount > 0
      ? `<span class="card-badge annotation-count">批注 ${annotationCount}</span>`
      : '';
    const tagBadges = (it.tags || []).slice(0, 3)
      .map((tag) => `<span class="library-card-tag" title="${escapeHtml(tag)}">${escapeHtml(tag)}</span>`)
      .join('');
    const selectBox = selectMode
      ? `<label class="card-select" title="选择"><input type="checkbox" aria-label="选择${escapeHtml(it.title)}" /></label>`
      : '';
    // 多选时封面不再触发阅读，否则勾选途中容易误开阅读器
    const coverActs = readable && !selectMode;
    return `
      <div class="card" data-id="${escapeHtml(it.id)}">
        ${selectBox}
        <div class="card-cover${readable ? ' readable' : ''}" style="${coverStyle(it.cover)}"
          data-cover-state="${it.cover ? 'ready' : 'pending'}"
          ${coverActs ? 'data-act="read" role="button" tabindex="0" title="使用内置阅读器打开"' : ''}>${it.cover ? '' : `<div class="ph">${escapeHtml(it.title)}</div>`}
          ${tagBadges ? `<div class="library-card-tags">${tagBadges}</div>` : ''}
          <div class="card-cover-badges start">${badge}</div>
          <div class="card-cover-badges end">${annotationBadge}${noteBadge}</div>
        </div>
        <div class="card-title" title="${escapeHtml(it.title)}">${escapeHtml(it.title)}</div>
        ${(it.authors && it.authors.length) ? `<div class="card-sub">${escapeHtml(it.authors.slice(0, 2).join(', '))}</div>` : ''}
        ${selectMode ? '' : `<div class="lib-card-actions">
          ${readable ? cardAction('read', '阅读', true) : ''}
          ${cardAction('open', readable ? '外部打开' : '打开', !readable, !openable)}
          ${openable ? cardAction('reveal', '在文件夹中显示') : ''}
          ${it.url ? cardAction('page', '打开来源页面') : ''}
          ${cardAction('organize', '整理书架和标签')}
          ${cardAction('remove', '移除书籍')}
        </div>`}
      </div>`;
  }

  function bindCard(card) {
    const id = card.dataset.id;
    card.querySelectorAll('button').forEach((button) => {
      button.onclick = (event) => {
        event.stopPropagation();
        onAction(id, button.dataset.act);
      };
    });
    if (selectMode) {
      const box = card.querySelector('.card-select input');
      box.onclick = (event) => event.stopPropagation();
      box.onchange = () => toggleSelection(id, box.checked);
      card.onclick = () => toggleSelection(id);
      return;
    }
    const cover = card.querySelector('.card-cover[data-act="read"]');
    if (!cover) return;
    cover.onclick = (event) => {
      event.stopPropagation();
      onAction(id, 'read');
    };
    cover.onkeydown = (event) => {
      if (event.key !== 'Enter' && event.key !== ' ') return;
      event.preventDefault();
      onAction(id, 'read');
    };
  }

  function reconcileCards(items, noteCounts, annotationCounts) {
    const existing = new Map(
      Array.from(grid.querySelectorAll(':scope > .card')).map((card) => [card.dataset.id, card])
    );
    const keep = new Set();
    items.forEach((item, index) => {
      const id = String(item.id);
      const markup = cardHtml(item, noteCounts, annotationCounts).trim();
      let card = existing.get(id);
      if (!card || card.__peoplelibMarkup !== markup) {
        const template = document.createElement('template');
        template.innerHTML = markup;
        const replacement = template.content.firstElementChild;
        replacement.__peoplelibMarkup = markup;
        bindCard(replacement);
        if (card) card.replaceWith(replacement);
        card = replacement;
      }
      keep.add(id);
      const expected = grid.children[index] || null;
      if (expected !== card) grid.insertBefore(card, expected);
    });
    Array.from(grid.querySelectorAll(':scope > .card')).forEach((card) => {
      if (!keep.has(card.dataset.id)) card.remove();
    });
    Array.from(grid.children).forEach((child) => {
      if (!child.classList.contains('card')) child.remove();
    });
  }

  async function refresh(force) {
    if (!force && !dirty) return;
    const currentRefresh = ++refreshSeq;
    const [res, noteCountResult, annotationCountResult, shelfResult, tagResult] = await Promise.all([
      window.api.library.list(),
      window.api.reader.getNoteCounts().catch(() => null),
      window.api.reader.getAnnotationCounts().catch(() => null),
      window.api.library.listShelves(),
      window.api.library.listTags()
    ]);
    if (currentRefresh !== refreshSeq) return;
    dirty = false;
    if (!res.ok) { statusEl.textContent = '加载失败：' + res.error; return; }
    shelves = shelfResult && shelfResult.ok && Array.isArray(shelfResult.data)
      ? shelfResult.data
      : [];
    libraryTags = tagResult && tagResult.ok && Array.isArray(tagResult.data)
      ? tagResult.data
      : [];
    if (selectedShelf && selectedShelf !== '__uncategorized__'
      && !shelves.some((shelf) => shelf.id === selectedShelf)) selectedShelf = '';
    if (selectedTag && !libraryTags.some((tag) => tag.name === selectedTag)) selectedTag = '';
    renderOrganizationSidebar();
    const noteCounts = noteCountsOf(noteCountResult);
    const annotationCounts = noteCountsOf(annotationCountResult);
    const allItems = res.data.slice();
    const scopedItems = allItems.filter((item) => {
      if (selectedShelf === '__uncategorized__' && item.shelfId) return false;
      if (selectedShelf && selectedShelf !== '__uncategorized__' && item.shelfId !== selectedShelf) return false;
      if (selectedTag && !(item.tags || []).some((tag) => (
        String(tag).toLocaleLowerCase() === selectedTag.toLocaleLowerCase()
      ))) return false;
      return true;
    });
    const items = scopedItems
      .filter((item) => matchesSearch(item, searchQuery))
      .sort(SORTERS[sortMode] || SORTERS.added);
    const missingCount = items.filter((it) => it.missing).length;
    statusEl.textContent = searchQuery
      ? `搜索“${searchQuery}”显示 ${items.length} 条，当前分类 ${scopedItems.length} 条`
        + `${missingCount ? `，其中 ${missingCount} 条文件缺失` : ''}`
      : (items.length === allItems.length
        ? `共 ${allItems.length} 条${missingCount ? `，${missingCount} 条文件缺失` : ''}`
        : `显示 ${items.length} 条，共 ${allItems.length} 条${missingCount ? `，当前 ${missingCount} 条文件缺失` : ''}`);
    // 全选只覆盖当前筛选结果；条目被筛掉或删除后，其选中状态一并作废，
    // 避免对看不见的书执行批量操作
    visibleIds = items.map((item) => String(item.id));
    const visible = new Set(visibleIds);
    Array.from(selectedIds).forEach((id) => { if (!visible.has(id)) selectedIds.delete(id); });
    if (!items.length) {
      grid.innerHTML = `<div class="empty">${allItems.length
        ? (searchQuery ? '没有匹配标题或作者的书籍' : '当前分类中没有书籍')
        : '书库为空，去「检索」页添加文献 / 图书吧'}</div>`;
      syncSelectionUi();
      return;
    }
    reconcileCards(items, noteCounts, annotationCounts);
    syncSelectionUi();
  }

  function selectShelf(id) {
    selectedShelf = String(id || '');
    selectedTag = '';
    dirty = true;
    refresh(true);
  }

  function selectTag(name) {
    selectedTag = selectedTag === name ? '' : name;
    selectedShelf = '';
    dirty = true;
    refresh(true);
  }

  function renderOrganizationSidebar() {
    document.querySelectorAll('#libraryTab .library-filter[data-shelf]').forEach((button) => {
      button.classList.toggle(
        'active',
        !selectedTag && (button.dataset.shelf || '') === selectedShelf
      );
    });
    const shelfList = $('libraryShelfList');
    shelfList.textContent = '';
    shelves.forEach((shelf) => {
      const row = document.createElement('div');
      row.className = 'library-shelf-row';
      const filter = document.createElement('button');
      filter.type = 'button';
      filter.className = 'library-filter';
      filter.classList.toggle('active', !selectedTag && selectedShelf === shelf.id);
      filter.textContent = shelf.name;
      filter.title = shelf.name;
      filter.onclick = () => selectShelf(shelf.id);

      const actions = document.createElement('div');
      actions.className = 'library-shelf-actions';
      const rename = document.createElement('button');
      rename.type = 'button';
      rename.className = 'notes-icon-btn';
      rename.textContent = '✎';
      rename.title = '重命名';
      rename.setAttribute('aria-label', `重命名${shelf.name}`);
      rename.onclick = () => renameShelf(shelf);
      const remove = document.createElement('button');
      remove.type = 'button';
      remove.className = 'notes-icon-btn danger';
      remove.textContent = '×';
      remove.title = '删除';
      remove.setAttribute('aria-label', `删除${shelf.name}`);
      remove.onclick = () => deleteShelf(shelf);
      actions.append(rename, remove);
      row.append(filter, actions);
      shelfList.appendChild(row);
    });

    const tagList = $('libraryTagList');
    tagList.textContent = '';
    if (!libraryTags.length) {
      const empty = document.createElement('div');
      empty.className = 'library-filter';
      empty.textContent = '暂无标签';
      tagList.appendChild(empty);
      return;
    }
    libraryTags.forEach((tag) => {
      const row = document.createElement('div');
      row.className = 'library-tag-row';
      const button = document.createElement('button');
      button.type = 'button';
      button.className = 'library-filter';
      button.classList.toggle('active', selectedTag === tag.name);
      const count = document.createElement('span');
      count.className = 'library-filter-count';
      count.textContent = String(tag.count || 0);
      const name = document.createElement('span');
      name.textContent = `# ${tag.name}`;
      button.append(name, count);
      button.onclick = () => selectTag(tag.name);
      const actions = document.createElement('div');
      actions.className = 'library-tag-actions';
      const rename = document.createElement('button');
      rename.type = 'button';
      rename.className = 'notes-icon-btn';
      rename.textContent = '✎';
      rename.title = '重命名';
      rename.setAttribute('aria-label', `重命名${tag.name}`);
      rename.onclick = () => renameTag(tag);
      const remove = document.createElement('button');
      remove.type = 'button';
      remove.className = 'notes-icon-btn danger';
      remove.textContent = '×';
      remove.title = '删除';
      remove.setAttribute('aria-label', `删除${tag.name}`);
      remove.onclick = () => deleteTag(tag);
      actions.append(rename, remove);
      row.append(button, actions);
      tagList.appendChild(row);
    });
  }

  async function addShelf() {
    const result = await openModal('新建书架', `
      <p>书架是单层分类，一本书只能放在一个书架中。</p>
      <input id="libraryShelfName" type="text" maxlength="100" placeholder="书架名称" />
      <div id="libraryShelfError" class="note-form-error"></div>
    `, async () => {
      const name = $('libraryShelfName').value.trim();
      if (!name) { $('libraryShelfError').textContent = '请输入书架名称'; return false; }
      const response = await window.api.library.addShelf({ name });
      if (!response || !response.ok) {
        $('libraryShelfError').textContent = (response && response.error) || '新建失败';
        return false;
      }
      return response.data;
    });
    if (!result) return;
    selectedShelf = result.id;
    selectedTag = '';
    dirty = true;
    await refresh(true);
  }

  async function renameShelf(shelf) {
    const result = await openModal('重命名书架', `
      <input id="libraryShelfName" type="text" maxlength="100" value="${escapeHtml(shelf.name)}" />
      <div id="libraryShelfError" class="note-form-error"></div>
    `, async () => {
      const name = $('libraryShelfName').value.trim();
      if (!name) { $('libraryShelfError').textContent = '请输入书架名称'; return false; }
      const response = await window.api.library.updateShelf(shelf.id, { name });
      if (!response || !response.ok) {
        $('libraryShelfError').textContent = (response && response.error) || '重命名失败';
        return false;
      }
      return true;
    });
    if (!result) return;
    dirty = true;
    await refresh(true);
  }

  async function deleteShelf(shelf) {
    const ok = await confirmModal(
      '删除书架',
      `确定删除「${shelf.name}」吗？书籍不会被删除，将移至「未分类」。`
    );
    if (!ok) return;
    const result = await window.api.library.removeShelf(shelf.id);
    if (!result || !result.ok) {
      await confirmModal('删除失败', (result && result.error) || '未知错误');
      return;
    }
    if (selectedShelf === shelf.id) selectedShelf = '__uncategorized__';
    dirty = true;
    await refresh(true);
  }

  async function addTag() {
    const result = await openModal('新建标签', `
      <p>标签可以同时分配给多本书。</p>
      <input id="libraryTagName" type="text" maxlength="100" placeholder="标签名称" />
      <div id="libraryTagError" class="note-form-error"></div>
    `, async () => {
      const name = $('libraryTagName').value.trim();
      if (!name) { $('libraryTagError').textContent = '请输入标签名称'; return false; }
      const response = await window.api.library.addTag({ name });
      if (!response || !response.ok) {
        $('libraryTagError').textContent = (response && response.error) || '新建失败';
        return false;
      }
      return response.data;
    });
    if (!result) return;
    selectedTag = result.name;
    selectedShelf = '';
    dirty = true;
    await refresh(true);
  }

  async function renameTag(tag) {
    const result = await openModal('重命名标签', `
      <input id="libraryTagName" type="text" maxlength="100" value="${escapeHtml(tag.name)}" />
      <div id="libraryTagError" class="note-form-error"></div>
    `, async () => {
      const name = $('libraryTagName').value.trim();
      if (!name) { $('libraryTagError').textContent = '请输入标签名称'; return false; }
      const response = await window.api.library.updateTag(tag.id, { name });
      if (!response || !response.ok) {
        $('libraryTagError').textContent = (response && response.error) || '重命名失败';
        return false;
      }
      return response.data;
    });
    if (!result) return;
    if (selectedTag === tag.name) selectedTag = result.name;
    dirty = true;
    await refresh(true);
  }

  async function deleteTag(tag) {
    const ok = await confirmModal(
      '删除标签',
      `确定删除「${tag.name}」吗？该标签会从所有书籍中移除，书籍不会被删除。`
    );
    if (!ok) return;
    const result = await window.api.library.removeTag(tag.id);
    if (!result || !result.ok) {
      await confirmModal('删除失败', (result && result.error) || '未知错误');
      return;
    }
    if (selectedTag === tag.name) selectedTag = '';
    dirty = true;
    await refresh(true);
  }

  // 批量整理：标签用三态复选框。indeterminate 表示"部分书有该标签"，
  // 保持这个状态就不改动这些书原有的标签；只有用户明确勾上或取消才统一应用。
  async function bulkOrganize() {
    const listed = await window.api.library.list();
    if (!listed || !listed.ok) {
      await confirmModal('整理失败', (listed && listed.error) || '无法读取书库');
      return;
    }
    const targets = selectedEntries(listed.data || []);
    if (!targets.length) return;

    const shelfIds = new Set(targets.map((item) => item.shelfId || ''));
    const sharedShelf = shelfIds.size === 1 ? [...shelfIds][0] : null;
    const options = shelves.map((shelf) => (
      `<option value="${escapeHtml(shelf.id)}"${sharedShelf === shelf.id ? ' selected' : ''}>${escapeHtml(shelf.name)}</option>`
    )).join('');

    const counts = new Map();
    targets.forEach((item) => (item.tags || []).forEach((tag) => {
      const key = String(tag).toLocaleLowerCase();
      counts.set(key, (counts.get(key) || 0) + 1);
    }));
    const tagOptions = libraryTags.map((tag) => {
      const held = counts.get(tag.name.toLocaleLowerCase()) || 0;
      const state = held === 0 ? 'none' : (held === targets.length ? 'all' : 'some');
      return `<label class="library-tag-option">
        <input type="checkbox" value="${escapeHtml(tag.name)}" data-state="${state}"${state === 'all' ? ' checked' : ''} />
        <span># ${escapeHtml(tag.name)}</span>
        <span class="library-filter-count">${state === 'some' ? `${held}/${targets.length}` : (tag.count || 0)}</span>
      </label>`;
    }).join('');

    // indeterminate 只能用 DOM 属性设置，HTML 里写不出来；
    // 点击后按 部分 -> 全选 -> 全不选 -> 部分 循环，保证"保持原样"始终可回到
    const primeTagBoxes = () => {
      document.querySelectorAll('#libraryBulkTags input[type="checkbox"]').forEach((box) => {
        if (box.dataset.state !== 'some') return;
        box.indeterminate = true;
        box.onclick = () => {
          const phase = box.dataset.phase || 'some';
          const next = phase === 'some' ? 'all' : (phase === 'all' ? 'none' : 'some');
          box.dataset.phase = next;
          box.indeterminate = next === 'some';
          box.checked = next === 'all';
        };
      });
    };

    const pending = openModal(`批量整理 ${targets.length} 本`, `
      <div class="library-organize-form">
        <label>书架
          <select id="libraryBulkShelf">
            ${sharedShelf === null ? '<option value="__keep__" selected>保持不变（所选书籍分属不同书架）</option>' : ''}
            <option value=""${sharedShelf === '' ? ' selected' : ''}>未分类</option>${options}
          </select>
        </label>
        <label>标签
          <details id="libraryBulkTags" class="library-tag-picker">
            <summary>选择标签（部分选中的标签保持原样）</summary>
            <div class="library-tag-options">${tagOptions || '<div class="library-tag-empty">暂无标签，请先在左侧新建</div>'}</div>
          </details>
        </label>
        <div id="libraryBulkError" class="note-form-error"></div>
      </div>
    `, async () => {
      const boxes = Array.from(document.querySelectorAll('#libraryBulkTags input[type="checkbox"]'));
      const add = [];
      const strip = [];
      boxes.forEach((box) => {
        if (box.indeterminate) return;
        if (box.checked) add.push(box.value);
        else if (box.dataset.state !== 'none') strip.push(box.value.toLocaleLowerCase());
      });
      const shelfValue = $('libraryBulkShelf').value;
      const errorEl = $('libraryBulkError');
      // 一次提交：逐条 update 会把整个书库索引重写 N 遍
      const patches = targets.map((item) => {
        const patch = {};
        if (shelfValue !== '__keep__') patch.shelfId = shelfValue || null;
        const kept = (item.tags || []).filter((tag) => !strip.includes(String(tag).toLocaleLowerCase()));
        const merged = kept.slice();
        add.forEach((tag) => {
          if (!merged.some((existing) => String(existing).toLocaleLowerCase() === tag.toLocaleLowerCase())) {
            merged.push(tag);
          }
        });
        patch.tags = merged;
        return { id: item.id, patch };
      });
      const response = await window.api.library.updateMany(patches);
      if (!response || !response.ok) {
        errorEl.textContent = (response && response.error) || '保存失败';
        return false;
      }
      return true;
    });
    primeTagBoxes();
    if (!await pending) return;
    setSelectMode(false);
  }

  async function bulkRemove() {
    const listed = await window.api.library.list();
    if (!listed || !listed.ok) {
      await confirmModal('移除失败', (listed && listed.error) || '无法读取书库');
      return;
    }
    const targets = selectedEntries(listed.data || []);
    if (!targets.length) return;
    const withFiles = targets.filter((item) => (item.files || []).some((file) => file.path)).length;
    const preview = targets.slice(0, 5).map((item) => `<li>${escapeHtml(item.title)}</li>`).join('');

    const choice = await openModal('批量移除', `
      <p>确定移除以下 <b>${targets.length}</b> 本书吗？</p>
      <ul class="library-bulk-preview">${preview}</ul>
      ${targets.length > 5 ? `<p class="muted">另有 ${targets.length - 5} 本未列出</p>` : ''}
      ${withFiles ? `<p style="margin-top:8px"><label><input type="checkbox" id="bulkDelFiles" /> 同时删除已下载的文件（${withFiles} 本有文件）</label></p>` : ''}
      <p style="margin-top:8px"><label><input type="checkbox" id="bulkDelReadingData" /> 同时删除笔记、书签、进度和标注</label></p>
      <p class="muted" style="margin-top:6px">默认保留阅读资料，移除后仍可在「我的笔记」中查看。</p>
    `, () => ({
      deleteFiles: !!(document.getElementById('bulkDelFiles') || {}).checked,
      deleteReadingData: !!document.getElementById('bulkDelReadingData').checked
    }));
    if (!choice) return;

    const removed = await window.api.library.removeMany(targets.map((item) => item.id), choice);
    setSelectMode(false);
    if (!removed || !removed.ok) {
      await confirmModal('移除失败', (removed && removed.error) || '未知错误');
      return;
    }
    statusEl.textContent = `已移除 ${(removed.data && removed.data.removed) || targets.length} 本`;
  }

  async function organizeBook(item) {
    const options = shelves.map((shelf) => (
      `<option value="${escapeHtml(shelf.id)}"${item.shelfId === shelf.id ? ' selected' : ''}>${escapeHtml(shelf.name)}</option>`
    )).join('');
    const selectedTags = new Set((item.tags || []).map((tag) => String(tag).toLocaleLowerCase()));
    const tagOptions = libraryTags.map((tag) => (
      `<label class="library-tag-option">
        <input type="checkbox" value="${escapeHtml(tag.name)}"${selectedTags.has(tag.name.toLocaleLowerCase()) ? ' checked' : ''} />
        <span># ${escapeHtml(tag.name)}</span>
        <span class="library-filter-count">${tag.count || 0}</span>
      </label>`
    )).join('');
    const result = await openModal('整理书籍', `
      <div class="library-organize-form">
        <label>书架
          <select id="libraryBookShelf"><option value="">未分类</option>${options}</select>
        </label>
        <label>标签
          <details id="libraryBookTags" class="library-tag-picker">
            <summary>选择标签${item.tags && item.tags.length ? `（已选 ${item.tags.length} 个）` : ''}</summary>
            <div class="library-tag-options">${tagOptions || '<div class="library-tag-empty">暂无标签，请先在左侧新建</div>'}</div>
          </details>
        </label>
        <div id="libraryOrganizeError" class="note-form-error"></div>
      </div>
    `, async () => {
      const tags = Array.from(
        document.querySelectorAll('#libraryBookTags input[type="checkbox"]:checked')
      ).map((input) => input.value);
      const response = await window.api.library.update(item.id, {
        shelfId: $('libraryBookShelf').value || null,
        tags
      });
      if (!response || !response.ok) {
        $('libraryOrganizeError').textContent = (response && response.error) || '保存失败';
        return false;
      }
      return true;
    });
    if (!result) return;
    dirty = true;
    await refresh(true);
  }

  async function onAction(id, act) {
    const res = await window.api.library.get(id);
    if (!res.ok || !res.data) return;
    const it = res.data;
    if (act === 'read') {
      const files = it.files || [];
      const idx = files.findIndex(isReadableFile);
      const r = await window.api.reader.open(id, idx >= 0 ? idx : undefined);
      if (!r.ok) await confirmModal('无法阅读', r.error || '打开阅读器失败');
    } else if (act === 'open') {
      const f = (it.files || []).find((x) => x.exists) || (it.files || [])[0];
      if (!f) return;
      const r = await window.api.openPath(f.path);
      if (!r.ok) await confirmModal('打开失败', r.error || '无法打开该文件');
    } else if (act === 'reveal') {
      const f = (it.files || []).find((x) => x.exists);
      if (f) window.api.showItem(f.path);
    } else if (act === 'page') {
      if (it.url) window.api.openExternal(it.url);
    } else if (act === 'organize') {
      await organizeBook(it);
    } else if (act === 'remove') {
      const hasFile = (it.files || []).some((f) => f.path);
      const r = await openModal('移除条目', `
        <p>确定移除「${escapeHtml(it.title)}」吗？</p>
        ${hasFile ? '<p style="margin-top:8px"><label><input type="checkbox" id="delFiles" /> 同时删除已下载的文件</label></p>' : ''}
        <p style="margin-top:8px"><label><input type="checkbox" id="delReadingData" /> 同时删除笔记、书签、进度和标注</label></p>
        <p class="muted" style="margin-top:6px">默认保留阅读资料，移除后仍可在「我的笔记」中查看。</p>
      `, () => ({
        deleteFiles: !!(document.getElementById('delFiles') || {}).checked,
        deleteReadingData: !!document.getElementById('delReadingData').checked
      }));
      if (!r) return;
      const removed = await window.api.library.remove(id, r);
      if (!removed || !removed.ok) {
        await confirmModal('移除失败', (removed && removed.error) || '未知错误');
        return;
      }
      dirty = true;
      refresh(true);
    }
  }

  async function addLocal() {
    const source = await openModal('添加本地内容', `
      <p>可以选择一个或多个文件，也可以递归导入整个文件夹。</p>
      <label class="local-import-choice">
        <input type="radio" name="localImportSource" value="files" checked />
        选择本地文件
      </label>
      <label class="local-import-choice">
        <input type="radio" name="localImportSource" value="folder" />
        选择本地文件夹
      </label>
    `, () => document.querySelector('input[name="localImportSource"]:checked').value);
    if (!source) return;

    const picked = await window.api.library.pickLocal(source);
    if (!picked || !picked.ok) {
      await confirmModal('无法导入', (picked && picked.error) || '选择本地内容失败');
      return;
    }
    if (!picked.data) return;
    const selection = picked.data;
    const sample = Array.isArray(selection.sample) ? selection.sample : [];
    const single = selection.count === 1 && sample[0];
    const displayPaths = (selection.paths || []).slice(0, 3)
      .map((value) => `<div class="settings-path">${escapeHtml(value)}</div>`).join('');
    const options = await openModal('导入本地图书', `
      <p>发现 <b>${selection.count}</b> 个支持的图书文件。</p>
      ${displayPaths}
      <div class="local-import-section">
        <div class="local-import-label">沿用原文件夹分类</div>
        <label class="local-import-choice">
          <input type="radio" name="localImportOrganization" value="none" checked />
          不自动分类
        </label>
        <label class="local-import-choice">
          <input type="radio" name="localImportOrganization" value="shelf" />
          使用每个文件的上一级目录作为书架
        </label>
        <label class="local-import-choice">
          <input type="radio" name="localImportOrganization" value="tag" />
          使用每个文件的上一级目录作为标签
        </label>
      </div>
      ${single ? `
        <div class="local-import-section">
          <input type="text" id="localTitle" maxlength="500" placeholder="标题" value="${escapeHtml(single.name.replace(/\.[^.]+$/, ''))}" />
          <input type="text" id="localAuthor" maxlength="300" placeholder="作者（可选）" />
        </div>
      ` : ''}
      <div id="localImportError" class="note-form-error"></div>
    `, () => ({
      organization: document.querySelector(
        'input[name="localImportOrganization"]:checked'
      ).value,
      title: single ? $('localTitle').value.trim() : '',
      author: single ? $('localAuthor').value.trim() : ''
    }));
    if (!options) return;
    const result = await window.api.library.importLocal(selection.selectionId, options);
    if (!result || !result.ok) {
      await confirmModal('导入失败', (result && result.error) || '未知错误');
      return;
    }
    dirty = true;
    await refresh(true);
    const data = result.data || {};
    statusEl.textContent = `已导入 ${data.added || 0} 本`
      + (data.skippedDuplicates ? `，跳过 ${data.skippedDuplicates} 个重复文件` : '')
      + ((data.skipped || 0) > (data.skippedDuplicates || 0)
        ? `，另跳过 ${(data.skipped || 0) - (data.skippedDuplicates || 0)} 个无效项`
        : '');
  }

  function markDirty() { dirty = true; }

  return { init, refresh, markDirty, getSortMode, setSortMode };
})();

window.Library = Library;