const Library = (() => {
  let dirty = true;
  let sortMode = localStorage.getItem('libSortMode') || 'added';
  let grid, statusEl;

  const SORTERS = {
    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')
  };

  function init() {
    grid = $('libGrid');
    statusEl = $('libStatus');
    $('addLocalBtn').onclick = addLocal;
    $('rescanBtn').onclick = rescan;
    window.api.library.onChanged(() => { dirty = true; 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);
  }

  async function refresh(force) {
    if (!force && !dirty) return;
    const res = await window.api.library.list();
    dirty = false;
    if (!res.ok) { statusEl.textContent = '加载失败：' + res.error; return; }
    const items = res.data.slice().sort(SORTERS[sortMode] || SORTERS.added);
    const missingCount = items.filter((it) => it.missing).length;
    statusEl.textContent = `共 ${items.length} 条` + (missingCount ? `，${missingCount} 条文件缺失` : '');
    if (!items.length) {
      grid.innerHTML = '<div class="empty">书库为空，去「检索」页添加文献 / 图书吧</div>';
      return;
    }
    grid.innerHTML = items.map((it) => {
      // exists 由主进程按实际磁盘状态给出：文件被手动删掉时要如实反映
      const openable = (it.files || []).some((f) => f.exists);
      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>');
      return `
      <div class="card" data-id="${escapeHtml(it.id)}">
        <div class="card-cover" style="${coverStyle(it.cover)}">${it.cover ? '' : `<div class="ph">${escapeHtml(it.title)}</div>`}</div>
        <div class="card-title">${escapeHtml(it.title)}</div>
        ${(it.authors && it.authors.length) ? `<div class="card-sub">${escapeHtml(it.authors.slice(0, 2).join(', '))}</div>` : ''}
        ${badge}
        <div class="lib-card-actions">
          <button class="open-btn" data-act="open" ${openable ? '' : 'disabled'}>打开</button>
          ${openable ? '<button data-act="reveal">定位</button>' : ''}
          ${it.url ? '<button data-act="page">页面</button>' : ''}
          <button data-act="remove">移除</button>
        </div>
      </div>`;
    }).join('');

    grid.querySelectorAll('.card').forEach((el) => {
      const id = el.dataset.id;
      el.querySelectorAll('button').forEach((btn) => {
        btn.onclick = (e) => { e.stopPropagation(); onAction(id, btn.dataset.act); };
      });
    });
  }

  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 === '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 === '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>' : ''}
      `, () => ({ del: !!(document.getElementById('delFiles') || {}).checked }));
      if (!r) return;
      await window.api.library.remove(id, r.del);
      dirty = true;
      refresh(true);
    }
  }

  async function addLocal() {
    const r = await window.api.pickFile();
    if (!r.ok || !r.data) return;
    const { path: p, name } = r.data;
    const res = await openModal('添加本地文件', `
      <p>文件：${escapeHtml(p)}</p>
      <input type="text" id="localTitle" placeholder="标题" value="${escapeHtml(name)}" />
      <input type="text" id="localAuthor" placeholder="作者（可选）" />
    `, () => ({
      title: (document.getElementById('localTitle').value || name).trim(),
      author: (document.getElementById('localAuthor').value || '').trim()
    }));
    if (!res) return;
    await window.api.library.add({
      title: res.title,
      authors: res.author ? [res.author] : [],
      files: [{ path: p, name: p.split(/[\\/]/).pop(), format: (p.split('.').pop() || '').toUpperCase() }]
    });
    dirty = true;
    refresh(true);
  }

  function markDirty() { dirty = true; }

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

window.Library = Library;