'use strict';

// ---------------------------------------------------------------------------
// Bookmarks
// ---------------------------------------------------------------------------

async function loadBookmarks(bookId) {
  try {
    const res = await fetch(`/books/${bookId}/bookmarks/`);
    const {ct, iv} = await res.json();
    if (ct) {
      _saveAnnotationsCache(bookId, 'bookmarks', ct, iv); // persist for offline
      const key = await getOrCreateEncKey();
      const plain = await decryptBytes(key, iv, ct);
      currentBookmarks = JSON.parse(new TextDecoder().decode(plain));
    } else {
      currentBookmarks = [];
    }
  } catch (e) {
    // offline fallback
    const cached = await _loadAnnotationsCache(bookId, 'bookmarks');
    if (cached?.ct) {
      try {
        const key = await getOrCreateEncKey();
        const plain = await decryptBytes(key, cached.iv, cached.ct);
        currentBookmarks = JSON.parse(new TextDecoder().decode(plain));
      } catch { currentBookmarks = []; }
    } else {
      currentBookmarks = [];
    }
  }
}

async function saveBookmarks() {
  if (!currentBookId) return;
  try {
    const key = await getOrCreateEncKey();
    const plain = new TextEncoder().encode(JSON.stringify(currentBookmarks));
    const {iv, ciphertext} = await encryptBytes(key, plain);
    const body = JSON.stringify({ct: ciphertext, iv});
    const url = `/books/${currentBookId}/bookmarks/`;
    _lastBookmarkBeacon = {url, body};
    _saveAnnotationsCache(currentBookId, 'bookmarks', ciphertext, iv); // keep local cache current
    await fetch(url, {
      method: 'POST',
      headers: {'Content-Type': 'application/json', 'X-CSRFToken': getCsrfToken()},
      body,
    });
    bookmarksDirty = false;
  } catch (e) {
    _markPendingSync(currentBookId, 'bookmarks');
  }
}

function addBookmark() {
  const contentEl = $('reader-content');
  if (!contentEl || !currentBookId) return;

  let label, anchor, scrollFraction;

  if (currentPdfDoc) {
    const page = pdfCurrentPage || 1;
    label = `Seite ${pdfPageLabel(page)}`;
    anchor = `pdf-page-${page}`;
    scrollFraction = (page - 1) / Math.max(1, pdfTotalPages - 1);
  } else {
    // Find first visible chapter div
    const chapters = contentEl.querySelectorAll('[data-epub-src]');
    let visibleChapter = null;
    for (const ch of chapters) {
      const rect = ch.getBoundingClientRect();
      if (rect.bottom > 0 && rect.top < window.innerHeight) {
        visibleChapter = ch;
        break;
      }
    }
    const src = visibleChapter?.getAttribute('data-epub-src') || '';
    label = src.split('/').pop().replace(/\.x?html?$/i, '') || 'Bookmark';
    anchor = src;
    scrollFraction = contentEl.scrollTop / (contentEl.scrollHeight - contentEl.clientHeight || 1);
  }

  const bm = {
    id: crypto.randomUUID(),
    label,
    anchor,
    scrollFraction,
    createdAt: new Date().toISOString(),
  };
  currentBookmarks.unshift(bm);
  bookmarksDirty = true;
  saveBookmarks();

  // Toast
  const toast = document.createElement('div');
  toast.className = 'reader-toast';
  toast.textContent = `★ Lesezeichen: ${label}`;
  document.body.appendChild(toast);
  setTimeout(() => toast.remove(), 2200);
}

function openBookmarksSidebar() {
  if (!currentBookmarks.length) {
    openSidebar('Lesezeichen', '<p class="muted">Noch keine Lesezeichen. Tippe beim Lesen auf ★.</p>');
    return;
  }
  let html = '<ul style="list-style:none;padding:0;">';
  for (const bm of currentBookmarks) {
    html += `<li class="bookmark-entry">
      <button class="btn-link" data-jump-bookmark="${escapeHtml(bm.id)}" style="flex:1;text-align:left;">
        ${escapeHtml(bm.label)}
      </button>
      <button class="btn-icon" data-delete-bookmark="${escapeHtml(bm.id)}" title="Löschen">✕</button>
    </li>`;
  }
  html += '</ul>';
  openSidebar('Lesezeichen', html);

  const body = $('sidebar-body');
  body.addEventListener('click', function _bmClick(e) {
    const jumpBtn = e.target.closest('[data-jump-bookmark]');
    const delBtn  = e.target.closest('[data-delete-bookmark]');
    if (jumpBtn) {
      body.removeEventListener('click', _bmClick);
      jumpToBookmark(jumpBtn.dataset.jumpBookmark);
    }
    if (delBtn) {
      const id = delBtn.dataset.deleteBookmark;
      currentBookmarks = currentBookmarks.filter(b => b.id !== id);
      bookmarksDirty = true;
      saveBookmarks();
      openBookmarksSidebar(); // re-render
    }
  });
}

function jumpToBookmark(id) {
  const bm = currentBookmarks.find(b => b.id === id);
  if (!bm) return;
  closeSidebar();
  _suppressScrollJumpDetect();
  setTimeout(() => {
    const contentEl = $('reader-content');
    if (!contentEl) return;
    if (bm.anchor.startsWith('pdf-page-')) {
      pdfGoToPage(parseInt(bm.anchor.replace('pdf-page-', ''), 10) || 1);
    } else {
      const target = Array.from(contentEl.querySelectorAll('[data-epub-src]'))
        .find(el => el.getAttribute('data-epub-src') === bm.anchor);
      if (target) {
        const top = target.getBoundingClientRect().top - contentEl.getBoundingClientRect().top;
        contentEl.scrollBy({top: top - 16, behavior: 'smooth'});
      } else {
        contentEl.scrollTop = bm.scrollFraction * (contentEl.scrollHeight - contentEl.clientHeight);
      }
    }
  }, 50);
}