'use strict';

// ---------------------------------------------------------------------------
// Export annotations — walks all highlights/notes of the current book in
// reading order and offers them as a downloadable plain-text file.
// ---------------------------------------------------------------------------
function _tocTitleForChapterSrc(chapterSrc) {
  if (!chapterSrc) return '';
  const entry = currentBookToc.find(t => (t.href || '').split('#')[0] === chapterSrc);
  return entry ? entry.label : '';
}

// Rough "how far through the book" position for a resolved range — there's no
// real page concept for reflowable EPUB text, so this is a coordinate of last
// resort: percent of total scrollable content height, good enough to roughly
// relocate a highlight/note later.
function _percentFromRange(range) {
  const contentEl = $('reader-content');
  if (!contentEl || !range) return null;
  // Share of the text before the range, like the reading progress.
  const block = _blockAncestor(range.startContainer);
  if (block && contentEl.contains(block)) {
    const blocks = Array.from(contentEl.querySelectorAll(EPUB_BLOCK_SELECTOR));
    const i = blocks.indexOf(block);
    if (i >= 0) {
      const idx = _bookCharIndex(contentEl);
      const at = idx.starts[i] + _charOffsetInBlock(block, range.startContainer, range.startOffset);
      return Math.max(0, Math.min(100, (at / idx.total) * 100));
    }
  }
  if (!contentEl.scrollHeight) return null;
  const contentRect = contentEl.getBoundingClientRect();
  const rangeRect = range.getBoundingClientRect();
  if (!rangeRect.width && !rangeRect.height) return null;
  const offsetWithinScroll = (rangeRect.top - contentRect.top) + contentEl.scrollTop;
  return Math.max(0, Math.min(100, (offsetWithinScroll / contentEl.scrollHeight) * 100));
}

function _sortedAnnotations() {
  const resolved = currentHighlights.map(h => {
    let range;
    try { range = resolveAnchorRange(h); } catch (e) { range = null; }
    return {h, range};
  });
  resolved.sort((a, b) => {
    if (!a.range || !b.range) return 0;
    return a.range.compareBoundaryPoints(Range.START_TO_START, b.range);
  });
  return resolved;
}

// Highlight colours as the export and the list name them.
function _hlColorName(color) {
  return ({yellow: 'gelb', green: 'grün', blue: 'blau', red: 'rot'})[color] || color;
}

function exportAnnotations() {
  if (!currentHighlights.length) {
    customAlert('In diesem Buch gibt es noch keine Markierungen oder Notizen.');
    return;
  }

  const resolved = _sortedAnnotations();

  const titleEl = $('reader-title');
  const bookTitle = (titleEl?.textContent || 'Buch').split(' — ')[0];
  const lines = [`${bookTitle} — Markierungen & Notizen`, `Exportiert: ${new Date().toISOString().slice(0, 10)}`, ''];

  let lastChapter = null;
  for (const {h, range} of resolved) {
    const chapterTitle = _tocTitleForChapterSrc(h.anchor?.chapterSrc) || h.anchor?.chapterSrc || '';
    if (chapterTitle !== lastChapter) {
      lines.push(`── ${chapterTitle || 'Abschnitt ohne Titel'} ──`);
      lastChapter = chapterTitle;
    }
    const pct = _percentFromRange(range);
    const coord = pct !== null ? ` (≈${_formatBookPercent(pct / 100)}% im Buch)` : '';
    if (h.type === 'note') {
      lines.push(`[Notiz]${coord} bei: „${(h.anchor?.quote || '').trim()}“`);
      if (h.note) lines.push(`    ${h.note}`);
    } else {
      lines.push(`[Markierung · ${_hlColorName(h.color || 'yellow')}]${coord} „${(h.anchor?.quote || '').trim()}“`);
      if (h.note) lines.push(`    Notiz: ${h.note}`);
    }
    lines.push('');
  }

  const blob = new Blob([lines.join('\n')], {type: 'text/plain;charset=utf-8'});
  const url = URL.createObjectURL(blob);
  const a = document.createElement('a');
  a.href = url;
  a.download = `${bookTitle.replace(/[^\w\-]+/g, '_')}-notizen.txt`;
  document.body.appendChild(a);
  a.click();
  a.remove();
  URL.revokeObjectURL(url);
}

// List of every highlight/note in the book, in reading order, each jumpable —
// the same pattern as the bookmarks sidebar, but for annotations. Unlike the
// margin panel (which only shows what's currently on-screen), this is a full
// overview, useful once a book has annotations scattered throughout.
function openAnnotationsSidebar() {
  if (!currentHighlights.length) {
    openSidebar('Markierungen & Notizen', '<p class="muted">Noch keine Markierungen oder Notizen.</p>');
    return;
  }

  const resolved = _sortedAnnotations();
  let html = '<ul style="list-style:none;padding:0;">';
  for (const {h, range} of resolved) {
    const pct = _percentFromRange(range);
    const pctLabel = pct !== null ? `≈${_formatBookPercent(pct / 100)}%` : '';
    const kind = h.type === 'note' ? 'Notiz' : `Markierung${h.color ? ' · ' + _hlColorName(h.color) : ''}`;
    const preview = h.note || h.anchor?.quote || '(kein Text)';
    html += `<li class="bookmark-entry">
      <button class="btn-link" data-jump-annotation="${escapeHtml(h.id)}" style="flex:1;text-align:left;">
        <span class="muted" style="font-size:11px;">${escapeHtml(kind)} ${pctLabel}</span><br>
        ${escapeHtml(preview.slice(0, 80))}
      </button>
      <button class="btn-icon" data-delete-annotation="${escapeHtml(h.id)}" title="Löschen">✕</button>
    </li>`;
  }
  html += '</ul>';
  openSidebar('Markierungen & Notizen', html);

  const body = $('sidebar-body');
  body.addEventListener('click', function _annClick(e) {
    const jumpBtn = e.target.closest('[data-jump-annotation]');
    const delBtn  = e.target.closest('[data-delete-annotation]');
    if (jumpBtn) {
      body.removeEventListener('click', _annClick);
      jumpToAnnotation(jumpBtn.dataset.jumpAnnotation);
    }
    if (delBtn) {
      deleteHighlight(delBtn.dataset.deleteAnnotation);
      openAnnotationsSidebar(); // re-render
    }
  });
}

function jumpToAnnotation(id) {
  const h = currentHighlights.find(x => x.id === id);
  if (!h) return;
  closeSidebar();
  _suppressScrollJumpDetect();
  setTimeout(() => {
    const contentEl = $('reader-content');
    if (!contentEl) return;
    let range;
    try { range = resolveAnchorRange(h); } catch (e) { range = null; }
    if (range) {
      const top = range.getBoundingClientRect().top - contentEl.getBoundingClientRect().top;
      contentEl.scrollBy({top: top - 16, behavior: 'smooth'});
    }
  }, 50);
}