'use strict';

// ---------------------------------------------------------------------------
// Reader Search
// ---------------------------------------------------------------------------

let _readerSearchDebounce = null;

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

  const existing = document.getElementById('reader-search-bar');
  if (existing) {
    existing.remove();
    readerSearchOpen = false;
    clearReaderSearch();
    return;
  }

  readerSearchOpen = true;
  const bar = document.createElement('div');
  bar.id = 'reader-search-bar';
  bar.className = 'reader-search-bar';
  bar.innerHTML = `
    <input type="text" id="reader-search-input" class="search-input" placeholder="Suchen …" style="width:160px;">
    <button class="btn-icon" id="rs-search-prev" title="Vorheriger Treffer">↑</button>
    <button class="btn-icon" id="rs-search-next" title="Nächster Treffer">↓</button>
    <span id="rs-search-count" class="muted"></span>
    <button class="btn-icon" id="rs-search-clear" title="Close">✕</button>
  `;
  overlay.insertBefore(bar, $('reader-body-row'));

  const input = bar.querySelector('#reader-search-input');
  input.focus();
  input.addEventListener('input', () => {
    clearTimeout(_readerSearchDebounce);
    _readerSearchDebounce = setTimeout(() => doReaderSearch(input.value.trim()), 300);
  });
  input.addEventListener('keydown', e => {
    if (e.key === 'Enter') { e.shiftKey ? readerSearchPrev() : readerSearchNext(); }
    if (e.key === 'Escape') { toggleReaderSearch(); }
  });
  bar.querySelector('#rs-search-prev').addEventListener('click', readerSearchPrev);
  bar.querySelector('#rs-search-next').addEventListener('click', readerSearchNext);
  bar.querySelector('#rs-search-clear').addEventListener('click', toggleReaderSearch);
}

async function doReaderSearch(query) {
  const contentEl = $('reader-content');
  if (!contentEl) return;
  const countEl = document.getElementById('rs-search-count');

  clearReaderSearchHighlights();
  searchMatches = [];
  searchMatchIndex = -1;

  if (!query) { if (countEl) countEl.textContent = ''; return; }

  if (!currentPdfDoc) {
    // EPUB: snapshot original content
    if (!searchOriginalContent) {
      searchOriginalContent = contentEl.innerHTML;
    } else {
      contentEl.innerHTML = searchOriginalContent;
      applyHighlightsToContent();
    }

    const walker = document.createTreeWalker(contentEl, NodeFilter.SHOW_TEXT);
    const lq = query.toLowerCase();
    const ranges = [];
    let node;
    while ((node = walker.nextNode())) {
      const text = node.textContent;
      const lt = text.toLowerCase();
      let idx = 0;
      while ((idx = lt.indexOf(lq, idx)) !== -1) {
        const range = document.createRange();
        range.setStart(node, idx);
        range.setEnd(node, idx + query.length);
        ranges.push(range);
        idx += query.length;
      }
    }

    // Insert marks in reverse to preserve range validity
    for (let i = ranges.length - 1; i >= 0; i--) {
      try {
        const mark = document.createElement('mark');
        mark.className = 'reader-search-match';
        ranges[i].surroundContents(mark);
        searchMatches.unshift(mark);
      } catch (e) {}
    }
  } else {
    // PDF: collect text layer spans
    const spans = contentEl.querySelectorAll('.pdf-text-layer > span');
    const lq = query.toLowerCase();
    for (const span of spans) {
      if (span.textContent.toLowerCase().includes(lq)) {
        span.classList.add('reader-search-match');
        searchMatches.push(span);
      }
    }
  }

  if (countEl) countEl.textContent = searchMatches.length ? `1 / ${searchMatches.length}` : '0';
  if (searchMatches.length) {
    searchMatchIndex = 0;
    scrollToSearchMatch(0);
  }
}

function clearReaderSearchHighlights() {
  if (!currentPdfDoc) {
    // EPUB: restore from snapshot
    if (searchOriginalContent !== null) {
      const contentEl = $('reader-content');
      if (contentEl) {
        contentEl.innerHTML = searchOriginalContent;
        applyHighlightsToContent();
      }
      searchOriginalContent = null;
    } else {
      // Just remove marks without full restore
      document.querySelectorAll('mark.reader-search-match').forEach(m => {
        const parent = m.parentNode;
        while (m.firstChild) parent.insertBefore(m.firstChild, m);
        parent.removeChild(m);
      });
    }
  } else {
    // PDF: remove highlight class from spans
    document.querySelectorAll('.reader-search-match').forEach(el => {
      el.classList.remove('reader-search-match', 'active');
    });
  }
  searchMatches = [];
  searchMatchIndex = -1;
}

function clearReaderSearch() {
  clearTimeout(_readerSearchDebounce);
  clearReaderSearchHighlights();
  readerSearchOpen = false;
  const countEl = document.getElementById('rs-search-count');
  if (countEl) countEl.textContent = '';
}

function scrollToSearchMatch(idx) {
  if (!searchMatches.length) return;
  _suppressScrollJumpDetect();
  searchMatches.forEach((m, i) => m.classList.toggle('active', i === idx));
  searchMatches[idx].scrollIntoView({behavior: 'smooth', block: 'center'});
  const countEl = document.getElementById('rs-search-count');
  if (countEl) countEl.textContent = `${idx + 1} / ${searchMatches.length}`;
}

function readerSearchNext() {
  if (!searchMatches.length) return;
  searchMatchIndex = (searchMatchIndex + 1) % searchMatches.length;
  scrollToSearchMatch(searchMatchIndex);
}

function readerSearchPrev() {
  if (!searchMatches.length) return;
  searchMatchIndex = (searchMatchIndex - 1 + searchMatches.length) % searchMatches.length;
  scrollToSearchMatch(searchMatchIndex);
}