/**
 * PDF Tools Module
 * Images to PDF, Merge PDFs, Split PDF
 */

// =============== Images to PDF ===============

let img2pdfFiles = [];

function initImagesToPdf() {
  const dropZone = document.getElementById('img2pdfDropZone');
  const fileInput = document.getElementById('img2pdf_files');
  const preview = document.getElementById('img2pdfPreview');
  const btnCreate = document.getElementById('btnImg2Pdf');
  const btnClear = document.getElementById('btnImg2PdfClear');
  const progress = document.getElementById('img2pdfProgress');

  if (!dropZone || !fileInput) return;

  // Click to browse - handle clicks on the drop zone and its children
  dropZone.addEventListener('click', (e) => {
    // Don't trigger if clicking on a remove button
    if (e.target.classList.contains('drop-zone-file-remove')) return;
    fileInput.click();
  });

  // Drag & drop
  ['dragenter', 'dragover'].forEach(e => {
    dropZone.addEventListener(e, (ev) => {
      ev.preventDefault();
      dropZone.classList.add('drag-over');
    });
  });

  ['dragleave', 'drop'].forEach(e => {
    dropZone.addEventListener(e, (ev) => {
      ev.preventDefault();
      dropZone.classList.remove('drag-over');
    });
  });

  dropZone.addEventListener('drop', (e) => {
    const files = Array.from(e.dataTransfer.files).filter(f => f.type.startsWith('image/'));
    addImages(files);
  });

  fileInput.addEventListener('change', () => {
    addImages(Array.from(fileInput.files));
    fileInput.value = '';
  });

  btnClear.addEventListener('click', () => {
    img2pdfFiles = [];
    renderImagePreview();
  });

  btnCreate.addEventListener('click', () => createPdfFromImages());

  function addImages(files) {
    files.forEach(file => {
      img2pdfFiles.push(file);
    });
    renderImagePreview();
    showToast('Images Added', `${files.length} image(s) added`, 'success', 2000);
  }

  function renderImagePreview() {
    preview.innerHTML = '';
    btnCreate.disabled = img2pdfFiles.length === 0;
    btnClear.disabled = img2pdfFiles.length === 0;

    img2pdfFiles.forEach((file, index) => {
      const card = document.createElement('div');
      card.className = 'image-card';
      card.draggable = true;
      card.dataset.index = index;
      
      const url = URL.createObjectURL(file);
      card.innerHTML = `
        <img class="image-thumb" src="${url}" alt="${file.name}" />
        <div class="image-meta">
          <div class="image-filename">${file.name}</div>
          <div class="image-info">
            <span class="image-badge">#${index + 1}</span>
            <button class="drop-zone-file-remove" data-index="${index}">×</button>
          </div>
        </div>
      `;

      // Remove button
      card.querySelector('.drop-zone-file-remove').addEventListener('click', (e) => {
        e.stopPropagation();
        img2pdfFiles.splice(index, 1);
        renderImagePreview();
      });

      // Drag reorder
      card.addEventListener('dragstart', (e) => {
        e.dataTransfer.setData('text/plain', index);
        card.style.opacity = '0.5';
      });

      card.addEventListener('dragend', () => {
        card.style.opacity = '1';
      });

      card.addEventListener('dragover', (e) => {
        e.preventDefault();
        card.style.borderColor = 'var(--primary)';
      });

      card.addEventListener('dragleave', () => {
        card.style.borderColor = '';
      });

      card.addEventListener('drop', (e) => {
        e.preventDefault();
        card.style.borderColor = '';
        const fromIndex = parseInt(e.dataTransfer.getData('text/plain'));
        const toIndex = index;
        if (fromIndex !== toIndex) {
          const item = img2pdfFiles.splice(fromIndex, 1)[0];
          img2pdfFiles.splice(toIndex, 0, item);
          renderImagePreview();
        }
      });

      preview.appendChild(card);
    });
  }
}


async function createPdfFromImages() {
  if (img2pdfFiles.length === 0) {
    showToast('No Images', 'Add images first', 'error');
    return;
  }

  const btn = document.getElementById('btnImg2Pdf');
  const progress = document.getElementById('img2pdfProgress');

  setButtonLoading(btn, true, 'Creating...');
  showProgress(progress, true, true);

  try {
    const fd = new FormData();
    img2pdfFiles.forEach((file, i) => {
      fd.append('files', file);
    });
    fd.append('order', img2pdfFiles.map((_, i) => i).join(','));
    fd.append('output_name', document.getElementById('img2pdf_output').value || 'images.pdf');
    fd.append('page_size', document.getElementById('img2pdf_pagesize').value || 'a4');

    const res = await fetch('/api/images-to-pdf', { method: 'POST', body: fd });

    if (!res.ok) {
      const err = await res.json().catch(() => ({ detail: 'Failed' }));
      throw new Error(err.detail);
    }

    const blob = await res.blob();
    const filename = document.getElementById('img2pdf_output').value || 'images.pdf';
    downloadBlob(blob, filename.endsWith('.pdf') ? filename : filename + '.pdf');

    showSuccessAnimation('PDF Created!', `${img2pdfFiles.length} images converted`);
    
    if (typeof addToRecentFiles === 'function') {
      addToRecentFiles(filename, 'images-to-pdf');
    }

  } catch (e) {
    showToast('Error', e.message, 'error');
  } finally {
    setButtonLoading(btn, false);
    showProgress(progress, false);
  }
}


// =============== Merge PDFs ===============

let mergeFiles = [];

function initMergePdf() {
  const dropZone = document.getElementById('mergeDropZone');
  const fileInput = document.getElementById('merge_files');
  const fileList = document.getElementById('mergeFileList');
  const btnMerge = document.getElementById('btnMerge');
  const btnClear = document.getElementById('btnMergeClear');
  const progress = document.getElementById('mergeProgress');

  if (!dropZone || !fileInput) return;

  // Click to browse - handle clicks on the drop zone and its children
  dropZone.addEventListener('click', (e) => {
    if (e.target.classList.contains('drop-zone-file-remove')) return;
    fileInput.click();
  });

  ['dragenter', 'dragover'].forEach(e => {
    dropZone.addEventListener(e, (ev) => {
      ev.preventDefault();
      dropZone.classList.add('drag-over');
    });
  });

  ['dragleave', 'drop'].forEach(e => {
    dropZone.addEventListener(e, (ev) => {
      ev.preventDefault();
      dropZone.classList.remove('drag-over');
    });
  });

  dropZone.addEventListener('drop', (e) => {
    const files = Array.from(e.dataTransfer.files).filter(f => f.type === 'application/pdf');
    addPdfs(files);
  });

  fileInput.addEventListener('change', () => {
    addPdfs(Array.from(fileInput.files));
    fileInput.value = '';
  });

  btnClear.addEventListener('click', () => {
    mergeFiles = [];
    renderMergeList();
  });

  btnMerge.addEventListener('click', () => mergePdfs());

  function addPdfs(files) {
    files.forEach(file => mergeFiles.push(file));
    renderMergeList();
    showToast('PDFs Added', `${files.length} file(s) added`, 'success', 2000);
  }

  function renderMergeList() {
    fileList.innerHTML = '';
    btnMerge.disabled = mergeFiles.length < 2;
    btnClear.disabled = mergeFiles.length === 0;

    mergeFiles.forEach((file, index) => {
      const item = document.createElement('div');
      item.style.cssText = 'display: flex; align-items: center; gap: 12px; padding: 12px; background: var(--border-light); border-radius: 8px; margin-bottom: 8px; cursor: move;';
      item.draggable = true;
      item.dataset.index = index;

      item.innerHTML = `
        <svg width="20" height="20" fill="none" stroke="var(--primary)" viewBox="0 0 24 24">
          <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 12h6m-6 4h6m2 5H7a2 2 0 01-2-2V5a2 2 0 012-2h5.586a1 1 0 01.707.293l5.414 5.414a1 1 0 01.293.707V19a2 2 0 01-2 2z"/>
        </svg>
        <span style="flex: 1; font-size: 13px; font-weight: 500;">${file.name}</span>
        <span style="font-size: 11px; color: var(--text-muted);">#${index + 1}</span>
        <button class="drop-zone-file-remove" data-index="${index}" style="padding: 4px 8px;">×</button>
      `;

      item.querySelector('.drop-zone-file-remove').addEventListener('click', (e) => {
        e.stopPropagation();
        mergeFiles.splice(index, 1);
        renderMergeList();
      });

      // Drag reorder
      item.addEventListener('dragstart', (e) => {
        e.dataTransfer.setData('text/plain', index);
        item.style.opacity = '0.5';
      });
      item.addEventListener('dragend', () => item.style.opacity = '1');
      item.addEventListener('dragover', (e) => {
        e.preventDefault();
        item.style.background = 'var(--primary-light)';
      });
      item.addEventListener('dragleave', () => item.style.background = '');
      item.addEventListener('drop', (e) => {
        e.preventDefault();
        item.style.background = '';
        const fromIndex = parseInt(e.dataTransfer.getData('text/plain'));
        if (fromIndex !== index) {
          const moved = mergeFiles.splice(fromIndex, 1)[0];
          mergeFiles.splice(index, 0, moved);
          renderMergeList();
        }
      });

      fileList.appendChild(item);
    });
  }
}

async function mergePdfs() {
  if (mergeFiles.length < 2) {
    showToast('Need More Files', 'Add at least 2 PDFs', 'error');
    return;
  }

  const btn = document.getElementById('btnMerge');
  const progress = document.getElementById('mergeProgress');

  setButtonLoading(btn, true, 'Merging...');
  showProgress(progress, true, true);

  try {
    const fd = new FormData();
    mergeFiles.forEach(file => fd.append('files', file));
    fd.append('order', mergeFiles.map((_, i) => i).join(','));
    fd.append('output_name', document.getElementById('merge_output').value || 'merged.pdf');

    const res = await fetch('/api/merge-pdf', { method: 'POST', body: fd });

    if (!res.ok) {
      const err = await res.json().catch(() => ({ detail: 'Failed' }));
      throw new Error(err.detail);
    }

    const blob = await res.blob();
    const filename = document.getElementById('merge_output').value || 'merged.pdf';
    downloadBlob(blob, filename.endsWith('.pdf') ? filename : filename + '.pdf');

    showSuccessAnimation('PDFs Merged!', `${mergeFiles.length} files combined`);

  } catch (e) {
    showToast('Error', e.message, 'error');
  } finally {
    setButtonLoading(btn, false);
    showProgress(progress, false);
  }
}


// =============== Split PDF ===============

let splitFile = null;

function initSplitPdf() {
  const dropZone = document.getElementById('splitDropZone');
  const fileInput = document.getElementById('split_file');
  const btnSplit = document.getElementById('btnSplit');
  const modeSelect = document.getElementById('split_mode');
  const pagesInput = document.getElementById('split_pages');
  const pagesLabel = document.getElementById('split_pages_label');
  const progress = document.getElementById('splitProgress');

  if (!dropZone) return;

  // Initialize drop zone
  initDropZone(dropZone, fileInput, {
    maxSize: 100 * 1024 * 1024,
    onFile: (file) => {
      splitFile = file;
      btnSplit.disabled = !file;
      if (file) {
        showToast('PDF Selected', file.name, 'success', 2000);
      }
    }
  });

  // Mode change - update label
  modeSelect.addEventListener('change', () => {
    const mode = modeSelect.value;
    if (mode === 'all') {
      pagesLabel.textContent = 'Not needed for this mode';
      pagesInput.placeholder = 'Not needed';
      pagesInput.disabled = true;
    } else if (mode === 'range') {
      pagesLabel.textContent = 'Pages to Extract';
      pagesInput.placeholder = 'e.g., 1,3,5-8';
      pagesInput.disabled = false;
    } else if (mode === 'chunks') {
      pagesLabel.textContent = 'Pages per Chunk';
      pagesInput.placeholder = 'e.g., 5';
      pagesInput.disabled = false;
    }
  });

  // Trigger initial state
  modeSelect.dispatchEvent(new Event('change'));

  btnSplit.addEventListener('click', () => splitPdf());
}

async function splitPdf() {
  if (!splitFile) {
    showToast('No PDF', 'Upload a PDF first', 'error');
    return;
  }

  const btn = document.getElementById('btnSplit');
  const progress = document.getElementById('splitProgress');
  const mode = document.getElementById('split_mode').value;
  const pages = document.getElementById('split_pages').value;

  if ((mode === 'range' || mode === 'chunks') && !pages.trim()) {
    showToast('Missing Input', 'Enter pages or chunk size', 'error');
    return;
  }

  setButtonLoading(btn, true, 'Splitting...');
  showProgress(progress, true, true);

  try {
    const fd = new FormData();
    fd.append('file', splitFile);
    fd.append('mode', mode);
    fd.append('pages', pages);
    fd.append('output_name', document.getElementById('split_output').value || 'split');

    const res = await fetch('/api/split-pdf', { method: 'POST', body: fd });

    if (!res.ok) {
      const err = await res.json().catch(() => ({ detail: 'Failed' }));
      throw new Error(err.detail);
    }

    const blob = await res.blob();
    const contentType = res.headers.get('content-type');
    const outputName = document.getElementById('split_output').value || 'split';
    
    if (contentType.includes('zip')) {
      downloadBlob(blob, `${outputName}.zip`);
    } else {
      downloadBlob(blob, `${outputName}.pdf`);
    }

    showSuccessAnimation('PDF Split!', 'Download started');

  } catch (e) {
    showToast('Error', e.message, 'error');
  } finally {
    setButtonLoading(btn, false);
    showProgress(progress, false);
  }
}


// =============== Utility ===============

function downloadBlob(blob, filename) {
  const url = URL.createObjectURL(blob);
  const a = document.createElement('a');
  a.href = url;
  a.download = filename;
  document.body.appendChild(a);
  a.click();
  a.remove();
  URL.revokeObjectURL(url);
}


// =============== PDF to Images ===============

let pdf2imgFile = null;

function initPdf2Img() {
  const dropZone = document.getElementById('pdf2imgDropZone');
  const fileInput = document.getElementById('pdf2img_file');
  const btn = document.getElementById('btnPdf2Img');

  if (!dropZone || !fileInput) return;

  initDropZone(dropZone, fileInput, {
    maxSize: 100 * 1024 * 1024,
    onFile: (file) => {
      pdf2imgFile = file;
      btn.disabled = !file;
      if (file) showToast('PDF Selected', file.name, 'success', 2000);
    }
  });

  btn.addEventListener('click', () => convertPdfToImages());
}

async function convertPdfToImages() {
  if (!pdf2imgFile) {
    showToast('No PDF', 'Upload a PDF first', 'error');
    return;
  }

  const btn = document.getElementById('btnPdf2Img');
  const progress = document.getElementById('pdf2imgProgress');

  setButtonLoading(btn, true, 'Converting...');
  showProgress(progress, true, true);

  try {
    const fd = new FormData();
    fd.append('file', pdf2imgFile);
    fd.append('format', document.getElementById('pdf2img_format').value);
    fd.append('dpi', document.getElementById('pdf2img_dpi').value);
    fd.append('pages', document.getElementById('pdf2img_pages').value);
    fd.append('output_name', document.getElementById('pdf2img_output').value || 'pages');

    const res = await fetch('/api/pdf-to-images', { method: 'POST', body: fd });

    if (!res.ok) {
      const err = await res.json().catch(() => ({ detail: 'Failed' }));
      throw new Error(err.detail);
    }

    const blob = await res.blob();
    const outputName = document.getElementById('pdf2img_output').value || 'pages';
    downloadBlob(blob, `${outputName}_images.zip`);

    showSuccessAnimation('Conversion Complete!', 'Images downloaded as ZIP');

  } catch (e) {
    showToast('Error', e.message, 'error');
  } finally {
    setButtonLoading(btn, false);
    showProgress(progress, false);
  }
}


// =============== Compress PDF ===============

let compressFile = null;

function initCompressPdf() {
  const dropZone = document.getElementById('compressDropZone');
  const fileInput = document.getElementById('compress_file');
  const btn = document.getElementById('btnCompress');
  const btnPreview = document.getElementById('btnCompressPreview');
  const qualitySlider = document.getElementById('compress_quality');
  const qualityVal = document.getElementById('compress_quality_val');

  if (!dropZone || !fileInput) return;

  initDropZone(dropZone, fileInput, {
    maxSize: 100 * 1024 * 1024,
    onFile: (file) => {
      compressFile = file;
      btn.disabled = !file;
      if (btnPreview) btnPreview.disabled = !file;
      const resultEl = document.getElementById('compressResult');
      const previewEl = document.getElementById('compressPreviewCard');
      if (resultEl) resultEl.style.display = 'none';
      if (previewEl) previewEl.style.display = 'none';
      if (file) {
        showToast('PDF Selected', file.name, 'success', 2000);
        // Trigger initial estimate
        updateCompressPdfEstimate();
      }
    }
  });

  // Quality slider with debounced estimate
  if (qualitySlider && qualityVal) {
    let estimateTimeout = null;
    qualitySlider.addEventListener('input', () => {
      qualityVal.textContent = qualitySlider.value;
      // Debounce the estimate call
      if (estimateTimeout) clearTimeout(estimateTimeout);
      estimateTimeout = setTimeout(() => {
        updateCompressPdfEstimate();
      }, 300);
    });
  }

  if (btnPreview) btnPreview.addEventListener('click', () => previewCompressPdf());
  btn.addEventListener('click', () => compressPdf());
}

async function updateCompressPdfEstimate() {
  if (!compressFile) return;
  
  const qualitySlider = document.getElementById('compress_quality');
  if (!qualitySlider) return;
  
  const quality = qualitySlider.value;
  
  // Create estimate display if it doesn't exist
  let displayDiv = document.getElementById('compressPdfEstimate');
  if (!displayDiv) {
    displayDiv = document.createElement('div');
    displayDiv.id = 'compressPdfEstimate';
    displayDiv.style.cssText = 'margin-top: 12px; padding: 12px; background: var(--border-light); border-radius: var(--radius); font-size: 13px;';
    const qualityGroup = qualitySlider.closest('.form-group');
    if (qualityGroup) {
      qualityGroup.appendChild(displayDiv);
    }
  }
  
  displayDiv.innerHTML = '<span style="color: var(--text-muted);">Estimating file size...</span>';
  
  try {
    const fd = new FormData();
    fd.append('file', compressFile);
    fd.append('quality', quality);
    
    const res = await fetch('/api/estimate/compress-pdf', { method: 'POST', body: fd });
    
    if (!res.ok) {
      displayDiv.innerHTML = '<span style="color: var(--text-muted);">Could not estimate</span>';
      return;
    }
    
    const data = await res.json();
    const origKB = (data.original_size / 1024).toFixed(1);
    const estKB = (data.estimated_size / 1024).toFixed(1);
    const origMB = (data.original_size / 1024 / 1024).toFixed(2);
    const estMB = (data.estimated_size / 1024 / 1024).toFixed(2);
    const reduction = data.reduction_percent;
    
    // Use KB for small files, MB for large
    const useKB = data.original_size < 1024 * 1024;
    const origDisplay = useKB ? `${origKB} KB` : `${origMB} MB`;
    const estDisplay = useKB ? `${estKB} KB` : `${estMB} MB`;
    
    displayDiv.innerHTML = `
      <div style="display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 8px;">
        <span><strong>Original:</strong> ${origDisplay}</span>
        <span style="color: var(--primary);">→</span>
        <span><strong>Estimated:</strong> ${estDisplay}</span>
        <span style="color: ${reduction > 0 ? 'var(--success)' : 'var(--text-muted)'}; font-weight: 600;">
          ${reduction > 0 ? '-' + reduction + '%' : 'Minimal reduction'}
        </span>
      </div>
    `;
  } catch (e) {
    console.error('Estimate error:', e);
    displayDiv.innerHTML = '<span style="color: var(--text-muted);">Could not estimate</span>';
  }
}

async function previewCompressPdf() {
  if (!compressFile) {
    showToast('No PDF', 'Upload a PDF first', 'error');
    return;
  }

  const btn = document.getElementById('btnCompressPreview');
  const previewCard = document.getElementById('compressPreviewCard');
  const originalImg = document.getElementById('compressPreviewOriginal');
  const processedImg = document.getElementById('compressPreviewProcessed');

  setButtonLoading(btn, true, 'Loading...');

  try {
    const fd = new FormData();
    fd.append('file', compressFile);
    fd.append('quality', document.getElementById('compress_quality').value);

    const res = await fetch('/api/preview/compress-pdf', { method: 'POST', body: fd });

    if (!res.ok) {
      const err = await res.json().catch(() => ({ detail: 'Failed' }));
      throw new Error(err.detail);
    }

    const data = await res.json();
    originalImg.src = 'data:image/png;base64,' + data.original;
    processedImg.src = 'data:image/png;base64,' + data.processed;
    previewCard.style.display = 'block';
    previewCard.scrollIntoView({ behavior: 'smooth', block: 'start' });
    
    showToast('Preview Ready', 'Compare original vs compressed', 'success', 2000);

  } catch (e) {
    showToast('Error', e.message, 'error');
  } finally {
    setButtonLoading(btn, false);
  }
}

async function compressPdf() {
  if (!compressFile) {
    showToast('No PDF', 'Upload a PDF first', 'error');
    return;
  }

  const btn = document.getElementById('btnCompress');
  const progress = document.getElementById('compressProgress');
  const resultDiv = document.getElementById('compressResult');
  const statsDiv = document.getElementById('compressStats');

  setButtonLoading(btn, true, 'Compressing...');
  showProgress(progress, true, true);
  resultDiv.style.display = 'none';

  try {
    const fd = new FormData();
    fd.append('file', compressFile);
    fd.append('quality', document.getElementById('compress_quality').value);
    fd.append('output_name', document.getElementById('compress_output').value || 'compressed.pdf');

    const res = await fetch('/api/compress-pdf', { method: 'POST', body: fd });

    if (!res.ok) {
      const err = await res.json().catch(() => ({ detail: 'Failed' }));
      throw new Error(err.detail);
    }

    const blob = await res.blob();
    const filename = document.getElementById('compress_output').value || 'compressed.pdf';
    downloadBlob(blob, filename.endsWith('.pdf') ? filename : filename + '.pdf');

    // Show compression stats
    const originalSize = res.headers.get('X-Original-Size');
    const compressedSize = res.headers.get('X-Compressed-Size');
    const reduction = res.headers.get('X-Reduction-Percent');

    if (originalSize && compressedSize) {
      const origMB = (parseInt(originalSize) / 1024 / 1024).toFixed(2);
      const compMB = (parseInt(compressedSize) / 1024 / 1024).toFixed(2);
      statsDiv.textContent = `${origMB} MB → ${compMB} MB (${reduction}% smaller)`;
      resultDiv.style.display = 'block';
    }

    showSuccessAnimation('PDF Compressed!', `Reduced by ${reduction}%`);

  } catch (e) {
    showToast('Error', e.message, 'error');
  } finally {
    setButtonLoading(btn, false);
    showProgress(progress, false);
  }
}


// =============== Rotate PDF ===============

let rotateFile = null;

function initRotatePdf() {
  const dropZone = document.getElementById('rotateDropZone');
  const fileInput = document.getElementById('rotate_file');
  const btn = document.getElementById('btnRotate');
  const btnPreview = document.getElementById('btnRotatePreview');

  if (!dropZone || !fileInput) return;

  initDropZone(dropZone, fileInput, {
    maxSize: 100 * 1024 * 1024,
    onFile: (file) => {
      rotateFile = file;
      btn.disabled = !file;
      btnPreview.disabled = !file;
      document.getElementById('rotatePreviewCard').style.display = 'none';
      if (file) showToast('PDF Selected', file.name, 'success', 2000);
    }
  });

  btnPreview.addEventListener('click', () => previewRotatePdf());
  btn.addEventListener('click', () => rotatePdf());
}

async function previewRotatePdf() {
  if (!rotateFile) {
    showToast('No PDF', 'Upload a PDF first', 'error');
    return;
  }

  const btn = document.getElementById('btnRotatePreview');
  const previewCard = document.getElementById('rotatePreviewCard');
  const originalImg = document.getElementById('rotatePreviewOriginal');
  const processedImg = document.getElementById('rotatePreviewProcessed');

  setButtonLoading(btn, true, 'Loading...');

  try {
    const fd = new FormData();
    fd.append('file', rotateFile);
    fd.append('rotation', document.getElementById('rotate_angle').value);

    const res = await fetch('/api/preview/rotate-pdf', { method: 'POST', body: fd });

    if (!res.ok) {
      const err = await res.json().catch(() => ({ detail: 'Failed' }));
      throw new Error(err.detail);
    }

    const data = await res.json();
    originalImg.src = 'data:image/png;base64,' + data.original;
    processedImg.src = 'data:image/png;base64,' + data.processed;
    previewCard.style.display = 'block';
    previewCard.scrollIntoView({ behavior: 'smooth', block: 'start' });
    
    showToast('Preview Ready', 'Compare original vs rotated', 'success', 2000);

  } catch (e) {
    showToast('Error', e.message, 'error');
  } finally {
    setButtonLoading(btn, false);
  }
}

async function rotatePdf() {
  if (!rotateFile) {
    showToast('No PDF', 'Upload a PDF first', 'error');
    return;
  }

  const btn = document.getElementById('btnRotate');
  const progress = document.getElementById('rotateProgress');

  setButtonLoading(btn, true, 'Rotating...');
  showProgress(progress, true, true);

  try {
    const fd = new FormData();
    fd.append('file', rotateFile);
    fd.append('rotation', document.getElementById('rotate_angle').value);
    fd.append('pages', document.getElementById('rotate_pages').value);
    fd.append('output_name', document.getElementById('rotate_output').value || 'rotated.pdf');

    const res = await fetch('/api/rotate-pdf', { method: 'POST', body: fd });

    if (!res.ok) {
      const err = await res.json().catch(() => ({ detail: 'Failed' }));
      throw new Error(err.detail);
    }

    const blob = await res.blob();
    const filename = document.getElementById('rotate_output').value || 'rotated.pdf';
    downloadBlob(blob, filename.endsWith('.pdf') ? filename : filename + '.pdf');

    showSuccessAnimation('PDF Rotated!', 'Download started');

  } catch (e) {
    showToast('Error', e.message, 'error');
  } finally {
    setButtonLoading(btn, false);
    showProgress(progress, false);
  }
}


// =============== Page Numbers ===============

let pagenumsFile = null;

function initPageNums() {
  const dropZone = document.getElementById('pagenumsDropZone');
  const fileInput = document.getElementById('pagenums_file');
  const btn = document.getElementById('btnPageNums');
  const btnPreview = document.getElementById('btnPageNumsPreview');

  if (!dropZone || !fileInput) return;

  initDropZone(dropZone, fileInput, {
    maxSize: 100 * 1024 * 1024,
    onFile: (file) => {
      pagenumsFile = file;
      btn.disabled = !file;
      btnPreview.disabled = !file;
      document.getElementById('pagenumsPreviewCard').style.display = 'none';
      if (file) showToast('PDF Selected', file.name, 'success', 2000);
    }
  });

  btnPreview.addEventListener('click', () => previewPageNums());
  btn.addEventListener('click', () => addPageNumbers());
}

async function previewPageNums() {
  if (!pagenumsFile) {
    showToast('No PDF', 'Upload a PDF first', 'error');
    return;
  }

  const btn = document.getElementById('btnPageNumsPreview');
  const previewCard = document.getElementById('pagenumsPreviewCard');
  const originalImg = document.getElementById('pagenumsPreviewOriginal');
  const processedImg = document.getElementById('pagenumsPreviewProcessed');

  setButtonLoading(btn, true, 'Loading...');

  try {
    const fd = new FormData();
    fd.append('file', pagenumsFile);
    fd.append('position', document.getElementById('pagenums_position').value);
    fd.append('format', document.getElementById('pagenums_format').value);
    fd.append('start_number', document.getElementById('pagenums_start').value);
    fd.append('font_size', document.getElementById('pagenums_fontsize').value);

    const res = await fetch('/api/preview/page-numbers', { method: 'POST', body: fd });

    if (!res.ok) {
      const err = await res.json().catch(() => ({ detail: 'Failed' }));
      throw new Error(err.detail);
    }

    const data = await res.json();
    originalImg.src = 'data:image/png;base64,' + data.original;
    processedImg.src = 'data:image/png;base64,' + data.processed;
    previewCard.style.display = 'block';
    previewCard.scrollIntoView({ behavior: 'smooth', block: 'start' });
    
    showToast('Preview Ready', 'Compare original vs numbered', 'success', 2000);

  } catch (e) {
    showToast('Error', e.message, 'error');
  } finally {
    setButtonLoading(btn, false);
  }
}

async function addPageNumbers() {
  if (!pagenumsFile) {
    showToast('No PDF', 'Upload a PDF first', 'error');
    return;
  }

  const btn = document.getElementById('btnPageNums');
  const progress = document.getElementById('pagenumsProgress');

  setButtonLoading(btn, true, 'Processing...');
  showProgress(progress, true, true);

  try {
    const fd = new FormData();
    fd.append('file', pagenumsFile);
    fd.append('position', document.getElementById('pagenums_position').value);
    fd.append('format', document.getElementById('pagenums_format').value);
    fd.append('start_number', document.getElementById('pagenums_start').value);
    fd.append('font_size', document.getElementById('pagenums_fontsize').value);
    fd.append('output_name', document.getElementById('pagenums_output').value || 'numbered.pdf');

    const res = await fetch('/api/add-page-numbers', { method: 'POST', body: fd });

    if (!res.ok) {
      const err = await res.json().catch(() => ({ detail: 'Failed' }));
      throw new Error(err.detail);
    }

    const blob = await res.blob();
    const filename = document.getElementById('pagenums_output').value || 'numbered.pdf';
    downloadBlob(blob, filename.endsWith('.pdf') ? filename : filename + '.pdf');

    showSuccessAnimation('Page Numbers Added!', 'Download started');

  } catch (e) {
    showToast('Error', e.message, 'error');
  } finally {
    setButtonLoading(btn, false);
    showProgress(progress, false);
  }
}


// =============== PDF OCR ===============

let ocrFile = null;
let ocrExtractedText = '';

function initPdfOcr() {
  const dropZone = document.getElementById('ocrDropZone');
  const fileInput = document.getElementById('ocr_file');
  const btn = document.getElementById('btnOcr');
  const copyBtn = document.getElementById('btnOcrCopy');
  const notice = document.getElementById('ocrNotice');

  if (!dropZone || !fileInput) return;

  // Check if Tesseract is available
  fetch('/api/ocr-status')
    .then(r => r.json())
    .then(data => {
      if (!data.available && notice) {
        notice.style.display = 'flex';
      }
    })
    .catch(() => {});

  initDropZone(dropZone, fileInput, {
    maxSize: 100 * 1024 * 1024,
    onFile: (file) => {
      ocrFile = file;
      btn.disabled = !file;
      document.getElementById('ocrResult').style.display = 'none';
      copyBtn.disabled = true;
      if (file) showToast('PDF Selected', file.name, 'success', 2000);
    }
  });

  btn.addEventListener('click', () => extractPdfText());
  copyBtn.addEventListener('click', () => copyOcrText());
}

async function extractPdfText() {
  if (!ocrFile) {
    showToast('No PDF', 'Upload a PDF first', 'error');
    return;
  }

  const btn = document.getElementById('btnOcr');
  const copyBtn = document.getElementById('btnOcrCopy');
  const progress = document.getElementById('ocrProgress');
  const resultDiv = document.getElementById('ocrResult');
  const textArea = document.getElementById('ocrText');

  setButtonLoading(btn, true, 'Extracting...');
  showProgress(progress, true, true);
  resultDiv.style.display = 'none';

  try {
    const fd = new FormData();
    fd.append('file', ocrFile);
    fd.append('language', document.getElementById('ocr_language').value);
    fd.append('pages', document.getElementById('ocr_pages').value);
    fd.append('dpi', document.getElementById('ocr_dpi').value);
    fd.append('output_format', 'json');

    const res = await fetch('/api/pdf-ocr', { method: 'POST', body: fd });

    if (!res.ok) {
      const err = await res.json().catch(() => ({ detail: 'Failed' }));
      throw new Error(err.detail);
    }

    const data = await res.json();
    ocrExtractedText = data.text;
    
    textArea.value = ocrExtractedText;
    resultDiv.style.display = 'block';
    copyBtn.disabled = false;

    showToast('Text Extracted', `${data.pages} page(s) processed`, 'success');

  } catch (e) {
    showToast('Error', e.message, 'error');
  } finally {
    setButtonLoading(btn, false);
    showProgress(progress, false);
  }
}

async function copyOcrText() {
  if (!ocrExtractedText) return;
  
  try {
    await navigator.clipboard.writeText(ocrExtractedText);
    showToast('Copied!', 'Text copied to clipboard', 'success', 2000);
  } catch (e) {
    showToast('Copy Failed', 'Please select and copy manually', 'error');
  }
}


// =============== Initialize All ===============

function initPdfTools() {
  initImagesToPdf();
  initMergePdf();
  initSplitPdf();
  initPdf2Img();
  initCompressPdf();
  initRotatePdf();
  initPageNums();
  initPdfOcr();
}