import { resetState } from './state.js';
import { formatBytes } from './utils/helpers.js';
import { tesseractLanguages } from './config/tesseract-languages.js';
import { icons, createIcons } from 'lucide';
import Sortable from 'sortablejs';

// Centralizing DOM element selection
export const dom = {
  gridView: document.getElementById('grid-view'),
  toolGrid: document.getElementById('tool-grid'),
  toolInterface: document.getElementById('tool-interface'),
  toolContent: document.getElementById('tool-content'),
  backToGridBtn: document.getElementById('back-to-grid'),
  loaderModal: document.getElementById('loader-modal'),
  loaderText: document.getElementById('loader-text'),
  alertModal: document.getElementById('alert-modal'),
  alertTitle: document.getElementById('alert-title'),
  alertMessage: document.getElementById('alert-message'),
  alertOkBtn: document.getElementById('alert-ok'),
  heroSection: document.getElementById('hero-section'),
  featuresSection: document.getElementById('features-section'),
  toolsHeader: document.getElementById('tools-header'),
  dividers: document.querySelectorAll('.section-divider'),
  hideSections: document.querySelectorAll('.hide-section'),
};

export const showLoader = (text = 'Processing...') => {
  dom.loaderText.textContent = text;
  dom.loaderModal.classList.remove('hidden');
};

export const hideLoader = () => dom.loaderModal.classList.add('hidden');

export const showAlert = (title: any, message: any) => {
  dom.alertTitle.textContent = title;
  dom.alertMessage.textContent = message;
  dom.alertModal.classList.remove('hidden');
};

export const hideAlert = () => dom.alertModal.classList.add('hidden');

export const switchView = (view: any) => {
  if (view === 'grid') {
    dom.gridView.classList.remove('hidden');
    dom.toolInterface.classList.add('hidden');
    // show hero and features and header
    dom.heroSection.classList.remove('hidden');
    dom.featuresSection.classList.remove('hidden');
    dom.toolsHeader.classList.remove('hidden');
    // show dividers
    dom.dividers.forEach((divider) => {
      divider.classList.remove('hidden');
    });
    // show hideSections
    dom.hideSections.forEach((section) => {
      section.classList.remove('hidden');
    });

    resetState();
  } else {
    dom.gridView.classList.add('hidden');
    dom.toolInterface.classList.remove('hidden');
    dom.featuresSection.classList.add('hidden');
    dom.heroSection.classList.add('hidden');
    dom.toolsHeader.classList.add('hidden');
    dom.dividers.forEach((divider) => {
      divider.classList.add('hidden');
    });
    dom.hideSections.forEach((section) => {
      section.classList.add('hidden');
    });
  }
};

const thumbnailState = {
  sortableInstances: {},
};

function initializeOrganizeSortable(containerId: any) {
  const container = document.getElementById(containerId);
  if (!container) return;

  if (thumbnailState.sortableInstances[containerId]) {
    thumbnailState.sortableInstances[containerId].destroy();
  }

  thumbnailState.sortableInstances[containerId] = Sortable.create(container, {
    animation: 150,
    ghostClass: 'sortable-ghost',
    chosenClass: 'sortable-chosen',
    dragClass: 'sortable-drag',
    filter: '.delete-page-btn',
    preventOnFilter: true,
    onStart: function (evt: any) {
      evt.item.style.opacity = '0.5';
    },
    onEnd: function (evt: any) {
      evt.item.style.opacity = '1';
    },
  });
}

/**
 * Renders page thumbnails for tools like 'Organize' and 'Rotate'.
 * @param {string} toolId The ID of the active tool.
 * @param {object} pdfDoc The loaded pdf-lib document instance.
 */
export const renderPageThumbnails = async (toolId: any, pdfDoc: any) => {
  const containerId = toolId === 'organize' ? 'page-organizer' : 'page-rotator';
  const container = document.getElementById(containerId);
  if (!container) return;

  container.innerHTML = '';
  showLoader('Rendering page previews...');

  const pdfData = await pdfDoc.save();
  // @ts-expect-error TS(2304) FIXME: Cannot find name 'pdfjsLib'.
  const pdf = await pdfjsLib.getDocument({ data: pdfData }).promise;

  for (let i = 1; i <= pdf.numPages; i++) {
    const page = await pdf.getPage(i);
    const viewport = page.getViewport({ scale: 0.5 });
    const canvas = document.createElement('canvas');
    canvas.height = viewport.height;
    canvas.width = viewport.width;
    const context = canvas.getContext('2d');
    await page.render({ canvasContext: context, viewport: viewport }).promise;

    const wrapper = document.createElement('div');
    wrapper.className = 'page-thumbnail relative group';
    // @ts-expect-error TS(2322) FIXME: Type 'number' is not assignable to type 'string'.
    wrapper.dataset.pageIndex = i - 1;

    const imgContainer = document.createElement('div');
    imgContainer.className =
      'w-full h-36 bg-gray-900 rounded-lg flex items-center justify-center overflow-hidden border-2 border-gray-600';

    const img = document.createElement('img');
    img.src = canvas.toDataURL();
    img.className = 'max-w-full max-h-full object-contain';

    imgContainer.appendChild(img);

    if (toolId === 'organize') {
      wrapper.className = 'page-thumbnail relative group';
      wrapper.appendChild(imgContainer);

      const pageNumSpan = document.createElement('span');
      pageNumSpan.className =
        'absolute top-1 left-1 bg-gray-900 bg-opacity-75 text-white text-xs rounded-full px-2 py-1';
      pageNumSpan.textContent = i.toString();

      const deleteBtn = document.createElement('button');
      deleteBtn.className =
        'delete-page-btn absolute top-1 right-1 bg-red-600 text-white rounded-full w-6 h-6 flex items-center justify-center';
      deleteBtn.innerHTML = '&times;';
      deleteBtn.addEventListener('click', (e) => {
        (e.currentTarget as HTMLElement).parentElement.remove();
        initializeOrganizeSortable(containerId);
      });

      wrapper.append(pageNumSpan, deleteBtn);
    } else if (toolId === 'rotate') {
      wrapper.className = 'page-rotator-item flex flex-col items-center gap-2';
      wrapper.dataset.rotation = '0';
      img.classList.add('transition-transform', 'duration-300');
      wrapper.appendChild(imgContainer);

      const controlsDiv = document.createElement('div');
      controlsDiv.className = 'flex items-center justify-center gap-3 w-full';

      const pageNumSpan = document.createElement('span');
      pageNumSpan.className = 'font-medium text-sm text-white';
      pageNumSpan.textContent = i.toString();

      const rotateBtn = document.createElement('button');
      rotateBtn.className =
        'rotate-btn btn bg-gray-700 hover:bg-gray-600 p-2 rounded-full';
      rotateBtn.title = 'Rotate 90°';
      rotateBtn.innerHTML = '<i data-lucide="rotate-cw" class="w-5 h-5"></i>';
      rotateBtn.addEventListener('click', (e) => {
        e.stopPropagation();
        const card = (e.currentTarget as HTMLElement).closest(
          '.page-rotator-item'
        ) as HTMLElement;
        const imgEl = card.querySelector('img');
        let currentRotation = parseInt(card.dataset.rotation);
        currentRotation = (currentRotation + 90) % 360;
        card.dataset.rotation = currentRotation.toString();
        imgEl.style.transform = `rotate(${currentRotation}deg)`;
      });

      controlsDiv.append(pageNumSpan, rotateBtn);
      wrapper.appendChild(controlsDiv);
    }

    container.appendChild(wrapper);
    createIcons({ icons });
  }

  if (toolId === 'organize') {
    initializeOrganizeSortable(containerId);
  }

  hideLoader();
};

/**
 * Renders a list of uploaded files in the specified container.
 * @param {HTMLElement} container The DOM element to render the list into.
 * @param {File[]} files The array of file objects.
 */
export const renderFileDisplay = (container: any, files: any) => {
  container.textContent = '';
  if (files.length > 0) {
    files.forEach((file: any) => {
      const fileDiv = document.createElement('div');
      fileDiv.className =
        'flex items-center justify-between bg-gray-700 p-3 rounded-lg text-sm';

      const nameSpan = document.createElement('span');
      nameSpan.className = 'truncate font-medium text-gray-200';
      nameSpan.textContent = file.name;

      const sizeSpan = document.createElement('span');
      sizeSpan.className = 'flex-shrink-0 ml-4 text-gray-400';
      sizeSpan.textContent = formatBytes(file.size);

      fileDiv.append(nameSpan, sizeSpan);
      container.appendChild(fileDiv);
    });
  }
};

const createFileInputHTML = (options = {}) => {
  // @ts-expect-error TS(2339) FIXME: Property 'multiple' does not exist on type '{}'.
  const multiple = options.multiple ? 'multiple' : '';
  // @ts-expect-error TS(2339) FIXME: Property 'accept' does not exist on type '{}'.
  const acceptedFiles = options.accept || 'application/pdf';
  // @ts-expect-error TS(2339) FIXME: Property 'showControls' does not exist on type '{}... Remove this comment to see the full error message
  const showControls = options.showControls || false; // NEW: Add this parameter

  return `
        <div id="drop-zone" class="relative flex flex-col items-center justify-center w-full h-48 border-2 border-dashed border-gray-600 rounded-xl cursor-pointer bg-gray-900 hover:bg-gray-700 transition-colors duration-300">
            <div class="flex flex-col items-center justify-center pt-5 pb-6">
                <i data-lucide="upload-cloud" class="w-10 h-10 mb-3 text-gray-400"></i>
                <p class="mb-2 text-sm text-gray-400"><span class="font-semibold">Click to select a file</span> or drag and drop</p>
                <p class="text-xs text-gray-500">${multiple ? 'PDFs or Images' : 'A single PDF file'}</p>
                <p class="text-xs text-gray-500">Your files never leave your device.</p>
            </div>
            <input id="file-input" type="file" class="absolute top-0 left-0 w-full h-full opacity-0 cursor-pointer" ${multiple} accept="${acceptedFiles}">
        </div>
        
        ${
          showControls
            ? `
            <!-- NEW: Add control buttons for multi-file uploads -->
            <div id="file-controls" class="hidden mt-4 flex gap-3">
                <button id="add-more-btn" class="btn bg-indigo-600 hover:bg-indigo-700 text-white font-semibold px-4 py-2 rounded-lg flex items-center gap-2">
                    <i data-lucide="plus"></i> Add More Files
                </button>
                <button id="clear-files-btn" class="btn bg-red-600 hover:bg-red-700 text-white font-semibold px-4 py-2 rounded-lg flex items-center gap-2">
                    <i data-lucide="x"></i> Clear All
                </button>
            </div>
        `
            : ''
        }
    `;
};

export const toolTemplates = {
  merge: () => `
    <h2 class="text-2xl font-bold text-white mb-4">Merge PDFs</h2>
    <p class="mb-6 text-gray-400">Combine whole files, or select specific pages to merge into a new document.</p>
    ${createFileInputHTML({ multiple: true, showControls: true })} 

    <div id="merge-options" class="hidden mt-6">
        <div class="flex gap-2 p-1 rounded-lg bg-gray-900 border border-gray-700 mb-4">
            <button id="file-mode-btn" class="flex-1 btn bg-indigo-600 text-white font-semibold py-2 rounded-md">File Mode</button>
            <button id="page-mode-btn" class="flex-1 btn text-gray-300 font-semibold py-2 rounded-md">Page Mode</button>
        </div>

        <div id="file-mode-panel">
            <div class="p-3 bg-gray-900 rounded-lg border border-gray-700 mb-3">
                <p class="text-sm text-gray-300"><strong class="text-white">How it works:</strong></p>
                <ul class="list-disc list-inside text-xs text-gray-400 mt-1 space-y-1">
                    <li>Click and drag the <i data-lucide="grip-vertical" class="inline-block w-3 h-3"></i> icon to change the order of the files.</li>
                    <li>In the "Pages" box for each file, you can specify ranges (e.g., "1-3, 5") to merge only those pages.</li>
                    <li>Leave the "Pages" box blank to include all pages from that file.</li>
                </ul>
            </div>
            <ul id="file-list" class="space-y-2"></ul>
        </div>

        <div id="page-mode-panel" class="hidden">
             <div class="p-3 bg-gray-900 rounded-lg border border-gray-700 mb-3">
                <p class="text-sm text-gray-300"><strong class="text-white">How it works:</strong></p>
                 <ul class="list-disc list-inside text-xs text-gray-400 mt-1 space-y-1">
                    <li>All pages from your uploaded PDFs are shown below.</li>
                    <li>Simply drag and drop the individual page thumbnails to create the exact order you want for your new file.</li>
                </ul>
            </div>
             <div id="page-merge-preview" class="grid grid-cols-4 sm:grid-cols-6 md:grid-cols-8 gap-4 p-4 bg-gray-900 rounded-lg border border-gray-700 min-h-[200px]"></div>
        </div>
        
        <button id="process-btn" class="btn-gradient w-full mt-6" disabled>Merge PDFs</button>
    </div>
`,

  split: () => `
    <h2 class="text-2xl font-bold text-white mb-4">Split PDF</h2>
    <p class="mb-6 text-gray-400">Extract pages from a PDF using various methods.</p>
    ${createFileInputHTML()}
    <div id="file-display-area" class="mt-4 space-y-2"></div>
    <div id="split-options" class="hidden mt-6">
        
        <label for="split-mode" class="block mb-2 text-sm font-medium text-gray-300">Split Mode</label>
        <select id="split-mode" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5 mb-4">
            <option value="range">Extract by Page Range (Default)</option>
            <option value="even-odd">Split by Even/Odd Pages</option>
            <option value="all">Split All Pages into Separate Files</option>
            <option value="visual">Select Pages Visually</option>
        </select>

        <div id="range-panel">
            <div class="p-3 bg-gray-900 rounded-lg border border-gray-700 mb-3">
                <p class="text-sm text-gray-300"><strong class="text-white">How it works:</strong></p>
                <ul class="list-disc list-inside text-xs text-gray-400 mt-1 space-y-1">
                    <li>Enter page numbers separated by commas (e.g., 2, 8, 14).</li>
                    <li>Enter page ranges using a hyphen (e.g., 5-10).</li>
                    <li>Combine them for complex selections (e.g., 1-3, 7, 12-15).</li>
                </ul>
            </div>
            <p class="mb-2 font-medium text-white">Total Pages: <span id="total-pages"></span></p>
            <label for="page-range" class="block mb-2 text-sm font-medium text-gray-300">Enter page range:</label>
            <input type="text" id="page-range" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5" placeholder="e.g., 1-5, 8">
        </div>

        <div id="even-odd-panel" class="hidden">
            <div class="p-3 bg-gray-900 rounded-lg border border-gray-700 mb-3">
                <p class="text-sm text-gray-300"><strong class="text-white">How it works:</strong></p>
                <p class="text-xs text-gray-400 mt-1">This will create a new PDF containing only the even or only the odd pages from your original document.</p>
            </div>
            <div class="flex gap-4">
                <label class="flex-1 flex items-center justify-center gap-2 p-3 rounded-md hover:bg-gray-700 cursor-pointer has-[:checked]:bg-indigo-600">
                    <input type="radio" name="even-odd-choice" value="odd" checked class="hidden">
                    <span class="font-semibold text-white">Odd Pages Only</span>
                </label>
                <label class="flex-1 flex items-center justify-center gap-2 p-3 rounded-md hover:bg-gray-700 cursor-pointer has-[:checked]:bg-indigo-600">
                    <input type="radio" name="even-odd-choice" value="even" class="hidden">
                    <span class="font-semibold text-white">Even Pages Only</span>
                </label>
            </div>
        </div>
        
        <div id="visual-select-panel" class="hidden">
             <div class="p-3 bg-gray-900 rounded-lg border border-gray-700 mb-3">
                <p class="text-sm text-gray-300"><strong class="text-white">How it works:</strong></p>
                <p class="text-xs text-gray-400 mt-1">Click on the page thumbnails below to select them. Click again to deselect. All selected pages will be extracted.</p>
            </div>
             <div id="page-selector-grid" class="grid grid-cols-4 sm:grid-cols-6 md:grid-cols-8 gap-4 p-4 bg-gray-900 rounded-lg border border-gray-700 min-h-[150px]"></div>
        </div>

        <div id="all-pages-panel" class="hidden p-3 bg-gray-900 rounded-lg border border-gray-700">
            <p class="text-sm text-gray-300"><strong class="text-white">How it works:</strong></p>
            <p class="text-xs text-gray-400 mt-1">This mode will create a separate PDF file for every single page in your document and download them together in one ZIP archive.</p>
        </div>
        
        <div id="zip-option-wrapper" class="hidden mt-4">
            <label class="flex items-center gap-2 text-sm font-medium text-gray-300">
                <input type="checkbox" id="download-as-zip" class="w-4 h-4 rounded text-indigo-600 bg-gray-700 border-gray-600 focus:ring-indigo-500">
                Download pages as individual files in a ZIP
            </label>
        </div>
        
        <button id="process-btn" class="btn-gradient w-full mt-6">Split PDF</button>

    </div>
`,
  encrypt: () => `
        <h2 class="text-2xl font-bold text-white mb-4">Encrypt PDF</h2>
        <p class="mb-6 text-gray-400">Upload a PDF to create a new, password-protected version.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <div id="encrypt-options" class="hidden space-y-4 mt-6">
            <div>
                <label for="password-input" class="block mb-2 text-sm font-medium text-gray-300">Set Encryption Password</label>
                <input type="password" id="password-input" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5" placeholder="Enter a strong password">
            </div>
            <div class="p-4 bg-gray-900 border border-yellow-500/30 text-yellow-200 rounded-lg">
                <h3 class="font-semibold text-base mb-2">Important Note</h3>
                <p class="text-sm text-gray-400">To create the secure file, each page is converted into an image. This means you won't be able to select text or click links in the final encrypted PDF.</p>
            </div>
            <button id="process-btn" class="btn-gradient w-full mt-6">Encrypt & Download</button>
        </div>
        <canvas id="pdf-canvas" class="hidden"></canvas>
    `,
  decrypt: () => `
        <h2 class="text-2xl font-bold text-white mb-4">Decrypt PDF</h2>
        <p class="mb-6 text-gray-400">Upload an encrypted PDF and provide its password to create an unlocked version.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <div id="decrypt-options" class="hidden space-y-4 mt-6">
            <div>
                <label for="password-input" class="block mb-2 text-sm font-medium text-gray-300">Enter PDF Password</label>
                <input type="password" id="password-input" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5" placeholder="Enter the current password">
            </div>
            <button id="process-btn" class="btn-gradient w-full mt-6">Decrypt & Download</button>
        </div>
        <canvas id="pdf-canvas" class="hidden"></canvas>
    `,
  organize: () => `
        <h2 class="text-2xl font-bold text-white mb-4">Organize PDF</h2>
        <p class="mb-6 text-gray-400">Reorder, rotate, or delete pages. Drag and drop pages to reorder them.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <div id="page-organizer" class="hidden grid grid-cols-3 sm:grid-cols-4 md:grid-cols-6 gap-4 my-6"></div>
        <button id="process-btn" class="btn-gradient w-full mt-6">Save Changes</button>
    `,

  rotate: () => `
        <h2 class="text-2xl font-bold text-white mb-4">Rotate PDF</h2>
        <p class="mb-6 text-gray-400">Rotate all or specific pages in a PDF document.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        
        <div id="rotate-all-controls" class="hidden my-6">
            <div class="bg-gray-900/50 border border-gray-700 rounded-lg p-4">
                <h3 class="text-sm font-semibold text-gray-400 mb-3 text-center">BATCH ACTIONS</h3>
                <div class="flex justify-center gap-4">
                    <button id="rotate-all-left-btn" class="flex items-center justify-center w-full px-4 py-2 text-sm font-medium text-gray-200 bg-gray-800 border border-gray-600 rounded-lg shadow-sm hover:bg-gray-700 hover:border-gray-500 focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-offset-gray-900 focus:ring-indigo-500 transform transition-all duration-150 active:scale-95">
                        <i data-lucide="rotate-ccw" class="mr-2 h-4 w-4"></i>
                        Rotate All Left
                    </button>
                    <button id="rotate-all-right-btn" class="flex items-center justify-center w-full px-4 py-2 text-sm font-medium text-gray-200 bg-gray-800 border border-gray-600 rounded-lg shadow-sm hover:bg-gray-700 hover:border-gray-500 focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-offset-gray-900 focus:ring-indigo-500 transform transition-all duration-150 active:scale-95">
                        <i data-lucide="rotate-cw" class="mr-2 h-4 w-4"></i>
                        Rotate All Right
                    </button>
                </div>
            </div>
        </div>
        <div id="page-rotator" class="hidden grid grid-cols-3 sm:grid-cols-4 md:grid-cols-6 gap-4 my-6"></div>
        <button id="process-btn" class="btn-gradient w-full mt-6">Save Rotations</button>
    `,

  'add-page-numbers': () => `
        <h2 class="text-2xl font-bold text-white mb-4">Add Page Numbers</h2>
        <p class="mb-6 text-gray-400">Add customizable page numbers to your PDF file.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <div id="pagenum-options" class="hidden grid grid-cols-1 md:grid-cols-2 gap-4 mt-6">
            <div>
                <label for="position" class="block mb-2 text-sm font-medium text-gray-300">Position</label>
                <select id="position" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
                    <option value="bottom-center">Bottom Center</option>
                    <option value="bottom-left">Bottom Left</option>
                    <option value="bottom-right">Bottom Right</option>
                    <option value="top-center">Top Center</option>
                    <option value="top-left">Top Left</option>
                    <option value="top-right">Top Right</option>
                </select>
            </div>
            <div>
                <label for="font-size" class="block mb-2 text-sm font-medium text-gray-300">Font Size</label>
                <input type="number" id="font-size" value="12" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
            </div>
            <div>
                <label for="number-format" class="block mb-2 text-sm font-medium text-gray-300">Format</label>
                <select id="number-format" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
                    <option value="default">1, 2, 3...</option>
                    <option value="page_x_of_y">Page 1/N, 2/N...</option>
                </select>
            </div>
            <div>
                <label for="text-color" class="block mb-2 text-sm font-medium text-gray-300">Text Color</label>
                <input type="color" id="text-color" value="#000000" class="w-full h-[42px] bg-gray-700 border border-gray-600 rounded-lg p-1 cursor-pointer">
            </div>
        </div>
        <button id="process-btn" class="btn-gradient w-full mt-6">Add Page Numbers</button>
    `,
  'pdf-to-jpg': () => `
        <h2 class="text-2xl font-bold text-white mb-4">PDF to JPG</h2>
        <p class="mb-6 text-gray-400">Convert each page of a PDF file into a high-quality JPG image.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <div id="jpg-preview" class="hidden text-center mt-6">
            <p class="mb-4 text-white">Click "Download All as ZIP" to get images for all pages.</p>
            <button id="process-btn" class="btn-gradient w-full mt-6">Download All as ZIP</button>
        </div>
    `,
  'jpg-to-pdf': () => `
        <h2 class="text-2xl font-bold text-white mb-4">JPG to PDF</h2>
        <p class="mb-6 text-gray-400">Convert one or more JPG images into a single PDF file.</p>
        ${createFileInputHTML({ multiple: true, accept: 'image/jpeg', showControls: true })}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <button id="process-btn" class="btn-gradient w-full mt-6">Convert to PDF</button>
    `,
  'scan-to-pdf': () => `
        <h2 class="text-2xl font-bold text-white mb-4">Scan to PDF</h2>
        <p class="mb-6 text-gray-400">Use your device's camera to scan documents and save them as a PDF. On desktop, this will open a file picker.</p>
        ${createFileInputHTML({ accept: 'image/*' })}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <button id="process-btn" class="btn-gradient w-full mt-6">Create PDF from Scans</button>
    `,

  crop: () => `
    <h2 class="text-2xl font-bold text-white mb-4">Crop PDF</h2>
    <p class="mb-6 text-gray-400">Click and drag to select a crop area on any page. You can set different crop areas for each page.</p>
    ${createFileInputHTML()}
    <div id="crop-editor" class="hidden">
        <div class="flex flex-col md:flex-row items-center justify-center gap-4 mb-4 p-3 bg-gray-900 rounded-lg border border-gray-700">
            <div id="page-nav" class="flex items-center gap-2"></div>
            <div class="border-l border-gray-600 h-6 mx-2 hidden md:block"></div>
            <div id="zoom-controls" class="flex items-center gap-2">
                <button id="zoom-out-btn" class="btn p-2 rounded-full bg-gray-700 hover:bg-gray-600" title="Zoom Out"><i data-lucide="zoom-out" class="w-5 h-5"></i></button>
                <button id="fit-page-btn" class="btn p-2 rounded-full bg-gray-700 hover:bg-gray-600" title="Fit to View"><i data-lucide="minimize" class="w-5 h-5"></i></button>
                <button id="zoom-in-btn" class="btn p-2 rounded-full bg-gray-700 hover:bg-gray-600" title="Zoom In"><i data-lucide="zoom-in" class="w-5 h-5"></i></button>
            </div>
             <div class="border-l border-gray-600 h-6 mx-2 hidden md:block"></div>
            <div id="crop-controls" class="flex items-center gap-2">
                 <button id="clear-crop-btn" class="btn bg-yellow-600 hover:bg-yellow-700 text-white font-semibold px-4 py-2 rounded-lg text-sm" title="Clear crop on this page">Clear Page</button>
                 <button id="clear-all-crops-btn" class="btn bg-red-600 hover:bg-red-700 text-white font-semibold px-4 py-2 rounded-lg text-sm" title="Clear all crop selections">Clear All</button>
            </div>
        </div>
        <div id="canvas-container" class="relative w-full overflow-auto bg-gray-900 rounded-lg border border-gray-600" style="height: 70vh;">
            <canvas id="canvas-editor" class="mx-auto cursor-crosshair"></canvas>
        </div>
        <button id="process-btn" class="btn-gradient w-full mt-6">Apply Crop & Save PDF</button>
    </div>
`,
  compress: () => `
    <h2 class="text-2xl font-bold text-white mb-4">Compress PDF</h2>
    <p class="mb-6 text-gray-400">Reduce file size by choosing the compression method that best suits your document.</p>
    ${createFileInputHTML()}
    <div id="file-display-area" class="mt-4 space-y-2"></div>
    <div id="compress-options" class="hidden mt-6 space-y-6">
        <div>
            <label for="compression-level" class="block mb-2 text-sm font-medium text-gray-300">Compression Level</label>
            <select id="compression-level" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5 focus:ring-indigo-500 focus:border-indigo-500">
                <option value="balanced">Balanced (Recommended)</option>
                <option value="high-quality">High Quality (Larger file)</option>
                <option value="small-size">Smallest Size (Lower quality)</option>
                <option value="extreme">Extreme (Very low quality)</option>
            </select>
        </div>

        <div>
            <label for="compression-algorithm" class="block mb-2 text-sm font-medium text-gray-300">Compression Algorithm</label>
            <select id="compression-algorithm" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5 focus:ring-indigo-500 focus:border-indigo-500">
                <option value="vector">Vector (For Text Heavy PDF)</option>
                <option value="photon">Photon (For Complex Images & Drawings)</option>
            </select>
            <p class="mt-2 text-xs text-gray-400">
                Choose 'Vector' for text based PDFs, or 'Photon' for scanned documents and complex images.
            </p>
        </div>

        <button id="process-btn" class="btn-gradient w-full mt-4" disabled>Compress PDF</button>
    </div>
`,
  'pdf-to-greyscale': () => `
        <h2 class="text-2xl font-bold text-white mb-4">PDF to Greyscale</h2>
        <p class="mb-6 text-gray-400">Convert all pages of a PDF to greyscale. This is done by rendering each page, applying a filter, and rebuilding the PDF.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <button id="process-btn" class="btn-gradient w-full mt-6">Convert to Greyscale</button>
    `,
  'pdf-to-zip': () => `
        <h2 class="text-2xl font-bold text-white mb-4">Combine PDFs into ZIP</h2>
        <p class="mb-6 text-gray-400">Select multiple PDF files to download them together in a single ZIP archive.</p>
        ${createFileInputHTML({ multiple: true, showControls: true })}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <button id="process-btn" class="btn-gradient w-full mt-6">Create ZIP File</button>
    `,

  'edit-metadata': () => `
    <h2 class="text-2xl font-bold text-white mb-4">Edit PDF Metadata</h2>
    <p class="mb-6 text-gray-400">Modify the core metadata fields of your PDF. Leave a field blank to clear it.</p>
    
    <div class="p-3 mb-6 bg-gray-900 border border-yellow-500/30 text-yellow-200/80 rounded-lg text-sm flex items-start gap-3">
        <i data-lucide="info" class="w-5 h-5 flex-shrink-0 mt-0.5"></i>
        <div>
            <strong class="font-semibold text-yellow-200">Important Note:</strong>
            This tool <code class="bg-gray-700 px-1 rounded text-white">pdf-lib</code> library, which may update the <strong>Producer</strong>, <strong>CreationDate</strong>, and <strong>ModDate</strong> fields due to its default behavior on upload. To accurately view a file's final metadata after editing, or just normal viewing, please use our <strong>View Metadata</strong> tool.
        </div>
    </div>

    ${createFileInputHTML()}
    
    <div id="metadata-form" class="hidden mt-6 space-y-4">
        <div class="grid grid-cols-1 sm:grid-cols-2 gap-4">
            <div>
                <label for="meta-title" class="block mb-2 text-sm font-medium text-gray-300">Title</label>
                <input type="text" id="meta-title" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
            </div>
            <div>
                <label for="meta-author" class="block mb-2 text-sm font-medium text-gray-300">Author</label>
                <input type="text" id="meta-author" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
            </div>
            <div>
                <label for="meta-subject" class="block mb-2 text-sm font-medium text-gray-300">Subject</label>
                <input type="text" id="meta-subject" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
            </div>
             <div>
                <label for="meta-keywords" class="block mb-2 text-sm font-medium text-gray-300">Keywords (comma-separated)</label>
                <input type="text" id="meta-keywords" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
            </div>
            <div>
                <label for="meta-creator" class="block mb-2 text-sm font-medium text-gray-300">Creator Tool</label>
                <input type="text" id="meta-creator" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
            </div>
            <div>
                <label for="meta-producer" class="block mb-2 text-sm font-medium text-gray-300">Producer Tool</label>
                <input type="text" id="meta-producer" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
            </div>
             <div>
                <label for="meta-creation-date" class="block mb-2 text-sm font-medium text-gray-300">Creation Date</label>
                <input type="datetime-local" id="meta-creation-date" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
            </div>
            <div>
                <label for="meta-mod-date" class="block mb-2 text-sm font-medium text-gray-300">Modification Date</label>
                <input type="datetime-local" id="meta-mod-date" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
            </div>
        </div>

        <div id="custom-metadata-container" class="space-y-3 pt-4 border-t border-gray-700">
             <h3 class="text-lg font-semibold text-white">Custom Fields</h3>
             <p class="text-sm text-gray-400 -mt-2">Note: Custom fields are not supported by all PDF readers.</p>
        </div>
        <button id="add-custom-meta-btn" class="btn border border-gray-600 hover:bg-gray-700 text-white font-semibold py-2 px-4 rounded-lg flex items-center gap-2">
            <i data-lucide="plus"></i> Add Custom Field
        </button>
        
    </div>

    <button id="process-btn" class="hidden btn-gradient w-full mt-6">Update Metadata & Download</button>
`,

  'remove-metadata': () => `
        <h2 class="text-2xl font-bold text-white mb-4">Remove PDF Metadata</h2>
        <p class="mb-6 text-gray-400">Completely remove identifying metadata from your PDF.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <button id="process-btn" class="hidden mt-6 btn-gradient w-full">Remove Metadata & Download</button>
    `,
  flatten: () => `
        <h2 class="text-2xl font-bold text-white mb-4">Flatten PDF</h2>
        <p class="mb-6 text-gray-400">Make PDF forms and annotations non-editable by flattening them.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <button id="process-btn" class="hidden mt-6 btn-gradient w-full">Flatten PDF</button>
    `,
  'pdf-to-png': () => `
        <h2 class="text-2xl font-bold text-white mb-4">PDF to PNG</h2>
        <p class="mb-6 text-gray-400">Convert each page of a PDF file into a high-quality PNG image.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <div id="png-preview" class="hidden text-center mt-6">
            <p class="mb-4 text-white">Your file is ready. Click the button to download a ZIP file containing all PNG images.</p>
            <button id="process-btn" class="btn-gradient w-full">Download All as ZIP</button>
        </div>
    `,
  'png-to-pdf': () => `
        <h2 class="text-2xl font-bold text-white mb-4">PNG to PDF</h2>
        <p class="mb-6 text-gray-400">Convert one or more PNG images into a single PDF file.</p>
        ${createFileInputHTML({ multiple: true, accept: 'image/png', showControls: true })}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <button id="process-btn" class="btn-gradient w-full mt-6">Convert to PDF</button>
    `,
  'pdf-to-webp': () => `
        <h2 class="text-2xl font-bold text-white mb-4">PDF to WebP</h2>
        <p class="mb-6 text-gray-400">Convert each page of a PDF file into a modern WebP image.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <div id="webp-preview" class="hidden text-center mt-6">
            <p class="mb-4 text-white">Your file is ready. Click the button to download a ZIP file containing all WebP images.</p>
            <button id="process-btn" class="btn-gradient w-full">Download All as ZIP</button>
        </div>
    `,
  'webp-to-pdf': () => `
        <h2 class="text-2xl font-bold text-white mb-4">WebP to PDF</h2>
        <p class="mb-6 text-gray-400">Convert one or more WebP images into a single PDF file.</p>
        ${createFileInputHTML({ multiple: true, accept: 'image/webp', showControls: true })}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <button id="process-btn" class="btn-gradient w-full mt-6">Convert to PDF</button>
    `,
  edit: () => `
        <h2 class="text-2xl font-bold text-white mb-4">PDF Studio</h2>
        <p class="mb-6 text-gray-400">An all-in-one PDF workspace where you can annotate, draw, highlight, redact, add comments and shapes, take screenshots, and view PDFs.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <div id="embed-pdf-wrapper" class="hidden mt-6 w-full h-[75vh] border border-gray-600 rounded-lg">
            <div id="embed-pdf-container" class="w-full h-full"></div>
        </div>
    `,
  'delete-pages': () => `
        <h2 class="text-2xl font-bold text-white mb-4">Delete Pages</h2>
        <p class="mb-6 text-gray-400">Remove specific pages or ranges of pages from your PDF file.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <div id="delete-options" class="hidden mt-6">
            <p class="mb-2 font-medium text-white">Total Pages: <span id="total-pages"></span></p>
            <label for="pages-to-delete" class="block mb-2 text-sm font-medium text-gray-300">Enter pages to delete (e.g., 2, 4-6, 9):</label>
            <input type="text" id="pages-to-delete" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5 mb-6" placeholder="e.g., 2, 4-6, 9">
            <button id="process-btn" class="btn-gradient w-full">Delete Pages & Download</button>
        </div>
    `,
  'add-blank-page': () => `
        <h2 class="text-2xl font-bold text-white mb-4">Add Blank Page</h2>
        <p class="mb-6 text-gray-400">Insert a new blank page at a specific position in your document.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <div id="blank-page-options" class="hidden mt-6">
            <p class="mb-2 font-medium text-white">Total Pages: <span id="total-pages"></span></p>
            <label for="page-number" class="block mb-2 text-sm font-medium text-gray-300">Insert blank page after page number:</label>
            <input type="number" id="page-number" min="0" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5 mb-6" placeholder="Enter 0 to add to the beginning">
            <button id="process-btn" class="btn-gradient w-full">Add Page & Download</button>
        </div>
    `,
  'extract-pages': () => `
        <h2 class="text-2xl font-bold text-white mb-4">Extract Pages</h2>
        <p class="mb-6 text-gray-400">Extract specific pages from a PDF into separate files. Your files will download in a ZIP archive.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <div id="extract-options" class="hidden mt-6">
            <p class="mb-2 font-medium text-white">Total Pages: <span id="total-pages"></span></p>
            <label for="pages-to-extract" class="block mb-2 text-sm font-medium text-gray-300">Enter pages to extract (e.g., 2, 4-6, 9):</label>
            <input type="text" id="pages-to-extract" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5 mb-6" placeholder="e.g., 2, 4-6, 9">
            <button id="process-btn" class="btn-gradient w-full">Extract & Download ZIP</button>
        </div>
    `,

  'add-watermark': () => `
    <h2 class="text-2xl font-bold text-white mb-4">Add Watermark</h2>
    <p class="mb-6 text-gray-400">Apply a text or image watermark to every page of your PDF document.</p>
    ${createFileInputHTML()}
    <div id="file-display-area" class="mt-4 space-y-2"></div>

    <div id="watermark-options" class="hidden mt-6 space-y-4">
        <div class="flex gap-4 p-2 rounded-lg bg-gray-900">
            <label class="flex-1 flex items-center justify-center gap-2 p-3 rounded-md hover:bg-gray-700 cursor-pointer has-[:checked]:bg-indigo-600">
                <input type="radio" name="watermark-type" value="text" checked class="hidden">
                <span class="font-semibold text-white">Text</span>
            </label>
            <label class="flex-1 flex items-center justify-center gap-2 p-3 rounded-md hover:bg-gray-700 cursor-pointer has-[:checked]:bg-indigo-600">
                <input type="radio" name="watermark-type" value="image" class="hidden">
                <span class="font-semibold text-white">Image</span>
            </label>
        </div>

        <div id="text-watermark-options">
            <div class="grid grid-cols-1 sm:grid-cols-2 gap-4">
                <div>
                    <label for="watermark-text" class="block mb-2 text-sm font-medium text-gray-300">Watermark Text</label>
                    <input type="text" id="watermark-text" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5" placeholder="e.g., CONFIDENTIAL">
                </div>
                <div>
                    <label for="font-size" class="block mb-2 text-sm font-medium text-gray-300">Font Size</label>
                    <input type="number" id="font-size" value="72" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
                </div>
            </div>
             <div class="grid grid-cols-1 sm:grid-cols-2 gap-4 mt-4">
                <div>
                    <label for="text-color" class="block mb-2 text-sm font-medium text-gray-300">Text Color</label>
                    <input type="color" id="text-color" value="#000000" class="w-full h-[42px] bg-gray-700 border border-gray-600 rounded-lg p-1 cursor-pointer">
                </div>
                <div>
                    <label for="opacity-text" class="block mb-2 text-sm font-medium text-gray-300">Opacity (<span id="opacity-value-text">0.3</span>)</label>
                    <input type="range" id="opacity-text" value="0.3" min="0" max="1" step="0.1" class="w-full">
                </div>
            </div>
            <div class="mt-4">
                <label for="angle-text" class="block mb-2 text-sm font-medium text-gray-300">Angle (<span id="angle-value-text">0</span>°)</label>
                <input type="range" id="angle-text" value="0" min="-180" max="180" step="1" class="w-full">
            </div>
        </div>

        <div id="image-watermark-options" class="hidden space-y-4">
            <div>
                <label for="image-watermark-input" class="block mb-2 text-sm font-medium text-gray-300">Upload Watermark Image</label>
                <input type="file" id="image-watermark-input" accept="image/png, image/jpeg" class="w-full text-sm text-gray-400 file:mr-4 file:py-2 file:px-4 file:rounded-lg file:border-0 file:text-sm file:font-semibold file:bg-indigo-600 file:text-white hover:file:bg-indigo-700">
            </div>
            <div>
                <label for="opacity-image" class="block mb-2 text-sm font-medium text-gray-300">Opacity (<span id="opacity-value-image">0.3</span>)</label>
                <input type="range" id="opacity-image" value="0.3" min="0" max="1" step="0.1" class="w-full">
            </div>
            <div>
                <label for="angle-image" class="block mb-2 text-sm font-medium text-gray-300">Angle (<span id="angle-value-image">0</span>°)</label>
                <input type="range" id="angle-image" value="0" min="-180" max="180" step="1" class="w-full">
            </div>
        </div>

    </div>
    <button id="process-btn" class="hidden btn-gradient w-full mt-6">Add Watermark & Download</button>
`,

  'add-header-footer': () => `
    <h2 class="text-2xl font-bold text-white mb-4">Add Header & Footer</h2>
    <p class="mb-6 text-gray-400">Add custom text to the top and bottom margins of every page.</p>
    ${createFileInputHTML()}
    <div id="file-display-area" class="mt-4 space-y-2"></div>
    <div id="header-footer-options" class="hidden mt-6 space-y-4">
        
        <div class="p-4 bg-gray-900 border border-gray-700 rounded-lg">
            <h3 class="text-lg font-semibold text-white mb-3">Formatting Options</h3>
            <div class="grid grid-cols-1 sm:grid-cols-3 gap-4">
                <div>
                    <label for="page-range" class="block mb-2 text-sm font-medium text-gray-300">Page Range (optional)</label>
                    <input type="text" id="page-range" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5" placeholder="e.g., 1-3, 5">
                    <p class="text-xs text-gray-400 mt-1">Total pages: <span id="total-pages">0</span></p>
                </div>
                <div>
                    <label for="font-size" class="block mb-2 text-sm font-medium text-gray-300">Font Size</label>
                    <input type="number" id="font-size" value="10" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
                </div>
                <div>
                    <label for="font-color" class="block mb-2 text-sm font-medium text-gray-300">Font Color</label>
                    <input type="color" id="font-color" value="#000000" class="w-full h-[42px] bg-gray-700 border border-gray-600 rounded-lg p-1 cursor-pointer">
                </div>
            </div>
        </div>

        <div class="grid grid-cols-1 md:grid-cols-3 gap-4">
            <div>
                <label for="header-left" class="block mb-2 text-sm font-medium text-gray-300">Header Left</label>
                <input type="text" id="header-left" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
            </div>
            <div>
                <label for="header-center" class="block mb-2 text-sm font-medium text-gray-300">Header Center</label>
                <input type="text" id="header-center" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
            </div>
            <div>
                <label for="header-right" class="block mb-2 text-sm font-medium text-gray-300">Header Right</label>
                <input type="text" id="header-right" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
            </div>
        </div>
        <div class="grid grid-cols-1 md:grid-cols-3 gap-4">
            <div>
                <label for="footer-left" class="block mb-2 text-sm font-medium text-gray-300">Footer Left</label>
                <input type="text" id="footer-left" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
            </div>
            <div>
                <label for="footer-center" class="block mb-2 text-sm font-medium text-gray-300">Footer Center</label>
                <input type="text" id="footer-center" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
            </div>
            <div>
                <label for="footer-right" class="block mb-2 text-sm font-medium text-gray-300">Footer Right</label>
                <input type="text" id="footer-right" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
            </div>
        </div>
    </div>
    <button id="process-btn" class="hidden btn-gradient w-full mt-6">Apply Header & Footer</button>
`,

  'image-to-pdf': () => `
        <h2 class="text-2xl font-bold text-white mb-4">Image to PDF Converter</h2>
        <p class="mb-6 text-gray-400">Combine multiple images into a single PDF. Drag and drop to reorder.</p>
        ${createFileInputHTML({ multiple: true, accept: 'image/jpeg,image/png,image/webp', showControls: true })}
        <ul id="image-list" class="mt-4 grid grid-cols-3 sm:grid-cols-4 md:grid-cols-6 gap-4"></ul>
        <button id="process-btn" class="btn-gradient w-full mt-6">Convert to PDF</button>
    `,

  'change-permissions': () => `
    <h2 class="text-2xl font-bold text-white mb-4">Change PDF Permissions</h2>
    <p class="mb-6 text-gray-400">Unlock a PDF and re-save it with new passwords and permissions.</p>
    ${createFileInputHTML()}
    <div id="file-display-area" class="mt-4 space-y-2"></div>
    <div id="permissions-options" class="hidden mt-6 space-y-4">
        <div>
            <label for="current-password" class="block mb-2 text-sm font-medium text-gray-300">Current Password (to unlock)</label>
            <input type="password" id="current-password" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5" placeholder="Enter current password to open file">
        </div>

        <div class="grid grid-cols-1 md:grid-cols-2 gap-4">
            <div>
                <label for="new-user-password" class="block mb-2 text-sm font-medium text-gray-300">New User Password (optional)</label>
                <input type="password" id="new-user-password" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5" placeholder="Password to open file">
            </div>
            <div>
                <label for="new-owner-password" class="block mb-2 text-sm font-medium text-gray-300">New Owner Password (optional)</label>
                <input type="password" id="new-owner-password" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5" placeholder="Admin password for permissions">
            </div>
        </div>

        <div class="p-4 bg-gray-900 border border-blue-500/30 text-blue-200 rounded-lg">
            <h3 class="font-semibold text-base mb-2">How Passwords Work</h3>
            <ul class="list-disc list-inside text-sm text-gray-400 space-y-1">
                <li>The <strong>User Password</strong> is required to open and decrypt the PDF.</li>
                <li>The <strong>Owner Password</strong> is an admin key that bypasses all permissions.</li>
                <li>Leave both blank to create an unprotected PDF.</li>
                <li>Set an Owner Password to enforce the permissions you select below.</li>
            </ul>
        </div>
        
        <fieldset class="border border-gray-600 p-4 rounded-lg">
            <legend class="px-2 text-sm font-medium text-gray-300">Allow User to:</legend>
            <div class="grid grid-cols-1 md:grid-cols-2 gap-4 mt-2">
                <label class="flex items-center gap-2"><input type="checkbox" id="allow-printing" checked class="checkbox-style"> Print Document</label>
                <label class="flex items-center gap-2"><input type="checkbox" id="allow-copying" checked class="checkbox-style"> Copy Content</label>
                <label class="flex items-center gap-2"><input type="checkbox" id="allow-modifying" checked class="checkbox-style"> Modify Document</label>
                <label class="flex items-center gap-2"><input type="checkbox" id="allow-annotating" checked class="checkbox-style"> Annotate & Comment</label>
                <label class="flex items-center gap-2"><input type="checkbox" id="allow-filling-forms" checked class="checkbox-style"> Fill in Forms</label>
                <label class="flex items-center gap-2"><input type="checkbox" id="allow-content-accessibility" checked class="checkbox-style"> Enable Content Accessibility</label>
                <label class="flex items-center gap-2"><input type="checkbox" id="allow-document-assembly" checked class="checkbox-style"> Assemble Document</label>
            </div>
        </fieldset>
    </div>
    <button id="process-btn" class="hidden btn-gradient w-full mt-6">Save New Permissions</button>
`,

  'pdf-to-markdown': () => `
        <h2 class="text-2xl font-bold text-white mb-4">PDF to Markdown</h2>
        <p class="mb-6 text-gray-400">Convert a PDF's text content into a structured Markdown file.</p>
        ${createFileInputHTML({ accept: '.pdf' })}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <div class="hidden mt-4 p-3 bg-gray-900 border border-yellow-500/30 text-yellow-200 rounded-lg" id="quality-note">
            <p class="text-sm text-gray-400"><b>Note:</b> This is a text-focused conversion. Tables and images will not be included.</p>
        </div>
        <button id="process-btn" class="hidden btn-gradient w-full mt-6">Convert to Markdown</button>
    `,
  'txt-to-pdf': () => `
        <h2 class="text-2xl font-bold text-white mb-4">Text to PDF</h2>
        <p class="mb-6 text-gray-400">Type or paste your text below and convert it to a PDF with custom formatting.</p>
        <textarea id="text-input" rows="12" class="w-full bg-gray-900 border border-gray-600 text-gray-300 rounded-lg p-2.5 font-sans" placeholder="Start typing here..."></textarea>
        <div class="mt-6 grid grid-cols-2 md:grid-cols-4 gap-4">
            <div>
                <label for="font-family" class="block mb-2 text-sm font-medium text-gray-300">Font Family</label>
                <select id="font-family" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
                    <option value="Helvetica">Helvetica</option>
                    <option value="TimesRoman">Times New Roman</option>
                    <option value="Courier">Courier</option>
                </select>
            </div>
            <div>
                <label for="font-size" class="block mb-2 text-sm font-medium text-gray-300">Font Size</label>
                <input type="number" id="font-size" value="12" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
            </div>
            <div>
                <label for="page-size" class="block mb-2 text-sm font-medium text-gray-300">Page Size</label>
                <select id="page-size" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
                    <option value="A4">A4</option>
                    <option value="Letter">Letter</option>
                </select>
            </div>
            <div>
                <label for="text-color" class="block mb-2 text-sm font-medium text-gray-300">Text Color</label>
                <input type="color" id="text-color" value="#000000" class="w-full h-[42px] bg-gray-700 border border-gray-600 rounded-lg p-1 cursor-pointer">
            </div>
        </div>
        <button id="process-btn" class="btn-gradient w-full mt-6">Create PDF</button>
    `,
  'invert-colors': () => `
        <h2 class="text-2xl font-bold text-white mb-4">Invert PDF Colors</h2>
        <p class="mb-6 text-gray-400">Convert your PDF to a "dark mode" by inverting its colors. This works best on simple text and image documents.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <button id="process-btn" class="hidden btn-gradient w-full mt-6">Invert Colors & Download</button>
    `,
  'view-metadata': () => `
        <h2 class="text-2xl font-bold text-white mb-4">View PDF Metadata</h2>
        <p class="mb-6 text-gray-400">Upload a PDF to view its internal properties, such as Title, Author, and Creation Date.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <div id="metadata-results" class="hidden mt-6 p-4 bg-gray-900 border border-gray-700 rounded-lg"></div>
    `,
  'reverse-pages': () => `
        <h2 class="text-2xl font-bold text-white mb-4">Reverse PDF Pages</h2>
        <p class="mb-6 text-gray-400">Flip the order of all pages in your document, making the last page the first.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <button id="process-btn" class="hidden btn-gradient w-full mt-6">Reverse & Download</button>
    `,
  'md-to-pdf': () => `
        <h2 class="text-2xl font-bold text-white mb-4">Markdown to PDF</h2>
        <p class="mb-6 text-gray-400">Write in Markdown, select your formatting options, and get a high-quality, multi-page PDF. <br><strong class="text-gray-300">Note:</strong> Images linked from the web (e.g., https://...) require an internet connection to be rendered.</p>
        <div class="grid grid-cols-1 md:grid-cols-3 gap-4 mb-6">
            <div>
                <label for="page-format" class="block mb-2 text-sm font-medium text-gray-300">Page Format</label>
                <select id="page-format" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
                    <option value="a4">A4</option>
                    <option value="letter">Letter</option>
                </select>
            </div>
            <div>
                <label for="orientation" class="block mb-2 text-sm font-medium text-gray-300">Orientation</label>
                <select id="orientation" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
                    <option value="portrait">Portrait</option>
                    <option value="landscape">Landscape</option>
                </select>
            </div>
            <div>
                <label for="margin-size" class="block mb-2 text-sm font-medium text-gray-300">Margin Size</label>
                <select id="margin-size" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
                    <option value="normal">Normal</option>
                    <option value="narrow">Narrow</option>
                    <option value="wide">Wide</option>
                </select>
            </div>
        </div>
        <div class="h-[50vh]">
            <label for="md-input" class="block mb-2 text-sm font-medium text-gray-300">Markdown Editor</label>
            <textarea id="md-input" class="w-full h-full bg-gray-900 border border-gray-600 text-gray-300 rounded-lg p-3 font-mono resize-none" placeholder="# Welcome to Markdown..."></textarea>
        </div>
        <button id="process-btn" class="btn-gradient w-full mt-6">Create PDF from Markdown</button>
    `,
  'svg-to-pdf': () => `
        <h2 class="text-2xl font-bold text-white mb-4">SVG to PDF</h2>
        <p class="mb-6 text-gray-400">Convert one or more SVG vector images into a single PDF file.</p>
        ${createFileInputHTML({ multiple: true, accept: 'image/svg+xml', showControls: true })}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <button id="process-btn" class="btn-gradient w-full mt-6">Convert to PDF</button>
    `,
  'bmp-to-pdf': () => `
        <h2 class="text-2xl font-bold text-white mb-4">BMP to PDF</h2>
        <p class="mb-6 text-gray-400">Convert one or more BMP images into a single PDF file.</p>
        ${createFileInputHTML({ multiple: true, accept: 'image/bmp', showControls: true })}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <button id="process-btn" class="btn-gradient w-full mt-6">Convert to PDF</button>
    `,
  'heic-to-pdf': () => `
        <h2 class="text-2xl font-bold text-white mb-4">HEIC to PDF</h2>
        <p class="mb-6 text-gray-400">Convert one or more HEIC (High Efficiency) images from your iPhone or camera into a single PDF file.</p>
        ${createFileInputHTML({ multiple: true, accept: '.heic,.heif', showControls: true })}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <button id="process-btn" class="btn-gradient w-full mt-6">Convert to PDF</button>
    `,
  'tiff-to-pdf': () => `
        <h2 class="text-2xl font-bold text-white mb-4">TIFF to PDF</h2>
        <p class="mb-6 text-gray-400">Convert one or more single or multi-page TIFF images into a single PDF file.</p>
        ${createFileInputHTML({ multiple: true, accept: 'image/tiff', showControls: true })}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <button id="process-btn" class="btn-gradient w-full mt-6">Convert to PDF</button>
    `,
  'pdf-to-bmp': () => `
        <h2 class="text-2xl font-bold text-white mb-4">PDF to BMP</h2>
        <p class="mb-6 text-gray-400">Convert each page of a PDF file into a BMP image. Your files will be downloaded in a ZIP archive.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <button id="process-btn" class="btn-gradient w-full mt-6">Convert to BMP & Download ZIP</button>
    `,
  'pdf-to-tiff': () => `
        <h2 class="text-2xl font-bold text-white mb-4">PDF to TIFF</h2>
        <p class="mb-6 text-gray-400">Convert each page of a PDF file into a high-quality TIFF image. Your files will be downloaded in a ZIP archive.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <button id="process-btn" class="btn-gradient w-full mt-6">Convert to TIFF & Download ZIP</button>
    `,

  'split-in-half': () => `
        <h2 class="text-2xl font-bold text-white mb-4">Split Pages in Half</h2>
        <p class="mb-6 text-gray-400">Choose a method to divide every page of your document into two separate pages.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>

        <div id="split-half-options" class="hidden mt-6">
            <label for="split-type" class="block mb-2 text-sm font-medium text-gray-300">Select Split Type</label>
            <select id="split-type" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5 mb-6">
                <option value="vertical">Split Vertically (Left & Right halves)</option>
                <option value="horizontal">Split Horizontally (Top & Bottom halves)</option>
            </select>

            <button id="process-btn" class="btn-gradient w-full mt-6">Split PDF</button>
        </div>
    `,
  'page-dimensions': () => `
        <h2 class="text-2xl font-bold text-white mb-4">Analyze Page Dimensions</h2>
        <p class="mb-6 text-gray-400">Upload a PDF to see the precise dimensions, standard size, and orientation of every page.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>

        <div id="dimensions-results" class="hidden mt-6">
            <div class="flex justify-end mb-4">
                <label for="units-select" class="text-sm font-medium text-gray-300 self-center mr-3">Display Units:</label>
                <select id="units-select" class="bg-gray-700 border border-gray-600 text-white rounded-lg p-2">
                    <option value="pt" selected>Points (pt)</option>
                    <option value="in">Inches (in)</option>
                    <option value="mm">Millimeters (mm)</option>
                    <option value="px">Pixels (at 96 DPI)</option>
                </select>
            </div>
            <div class="overflow-x-auto rounded-lg border border-gray-700">
                <table class="min-w-full divide-y divide-gray-700 text-sm text-left">
                    <thead class="bg-gray-900">
                        <tr>
                            <th class="px-4 py-3 font-medium text-white">Page #</th>
                            <th class="px-4 py-3 font-medium text-white">Dimensions (W x H)</th>
                            <th class="px-4 py-3 font-medium text-white">Standard Size</th>
                            <th class="px-4 py-3 font-medium text-white">Orientation</th>
                        </tr>
                    </thead>
                    <tbody id="dimensions-table-body" class="divide-y divide-gray-700">
                        </tbody>
                </table>
            </div>
        </div>
    `,

  'n-up': () => `
        <h2 class="text-2xl font-bold text-white mb-4">N-Up Page Arrangement</h2>
        <p class="mb-6 text-gray-400">Combine multiple pages from your PDF onto a single sheet. This is great for creating booklets or proof sheets.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>

        <div id="n-up-options" class="hidden mt-6 space-y-4">
            <div class="grid grid-cols-1 sm:grid-cols-2 gap-4">
                <div>
                    <label for="pages-per-sheet" class="block mb-2 text-sm font-medium text-gray-300">Pages Per Sheet</label>
                    <select id="pages-per-sheet" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
                        <option value="2">2-Up</option>
                        <option value="4" selected>4-Up (2x2)</option>
                        <option value="9">9-Up (3x3)</option>
                        <option value="16">16-Up (4x4)</option>
                    </select>
                </div>
                <div>
                    <label for="output-page-size" class="block mb-2 text-sm font-medium text-gray-300">Output Page Size</label>
                    <select id="output-page-size" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
                        <option value="Letter">Letter (8.5 x 11 in)</option>
                        <option value="Legal">Legal (8.5 x 14 in)</option>
                        <option value="Tabloid">Tabloid (11 x 17 in)</option>
                        <option value="A4" selected>A4 (210 x 297 mm)</option>
                        <option value="A3">A3 (297 x 420 mm)</option>
                    </select>
                </div>
            </div>

            <div class="grid grid-cols-1 sm:grid-cols-2 gap-4">
                 <div>
                    <label for="output-orientation" class="block mb-2 text-sm font-medium text-gray-300">Output Orientation</label>
                    <select id="output-orientation" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
                        <option value="auto" selected>Automatic</option>
                        <option value="portrait">Portrait</option>
                        <option value="landscape">Landscape</option>
                    </select>
                </div>
                <div class="flex items-end pb-1">
                     <label class="flex items-center gap-2 text-sm font-medium text-gray-300">
                        <input type="checkbox" id="add-margins" checked class="w-4 h-4 rounded text-indigo-600 bg-gray-700 border-gray-600 focus:ring-indigo-500">
                        Add Margins & Gutters
                    </label>
                </div>
            </div>

            <div class="border-t border-gray-700 pt-4 grid grid-cols-1 sm:grid-cols-2 gap-4">
                <div class="flex items-center">
                     <label class="flex items-center gap-2 text-sm font-medium text-gray-300">
                        <input type="checkbox" id="add-border" class="w-4 h-4 rounded text-indigo-600 bg-gray-700 border-gray-600 focus:ring-indigo-500">
                        Draw Border Around Each Page
                    </label>
                </div>
                 <div id="border-color-wrapper" class="hidden">
                    <label for="border-color" class="block mb-2 text-sm font-medium text-gray-300">Border Color</label>
                     <input type="color" id="border-color" value="#000000" class="w-full h-[42px] bg-gray-700 border border-gray-600 rounded-lg p-1 cursor-pointer">
                </div>
            </div>

            <button id="process-btn" class="btn-gradient w-full mt-6">Create N-Up PDF</button>
        </div>
    `,

  'duplicate-organize': () => `
        <h2 class="text-2xl font-bold text-white mb-4">Page Manager</h2>
        <p class="mb-6 text-gray-400">Drag pages to reorder them. Use the <i data-lucide="copy-plus" class="inline-block w-4 h-4 text-green-400"></i> icon to duplicate a page or the <i data-lucide="x-circle" class="inline-block w-4 h-4 text-red-400"></i> icon to delete it.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>

        <div id="page-manager-options" class="hidden mt-6">
             <div id="page-grid" class="grid grid-cols-3 sm:grid-cols-4 md:grid-cols-6 gap-4 my-6">
                </div>
             <button id="process-btn" class="btn-gradient w-full mt-6">Save New PDF</button>
        </div>
    `,

  'combine-single-page': () => `
        <h2 class="text-2xl font-bold text-white mb-4">Combine to a Single Page</h2>
        <p class="mb-6 text-gray-400">Stitch all pages of your PDF together vertically to create one continuous, scrollable page.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>

        <div id="combine-options" class="hidden mt-6 space-y-4">
            <div class="grid grid-cols-1 sm:grid-cols-2 gap-4">
                <div>
                    <label for="page-spacing" class="block mb-2 text-sm font-medium text-gray-300">Spacing Between Pages (in points)</label>
                    <input type="number" id="page-spacing" value="18" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
                </div>
                <div>
                    <label for="background-color" class="block mb-2 text-sm font-medium text-gray-300">Background Color</label>
                    <input type="color" id="background-color" value="#FFFFFF" class="w-full h-[42px] bg-gray-700 border border-gray-600 rounded-lg p-1 cursor-pointer">
                </div>
            </div>
            <div>
                <label class="flex items-center gap-2 text-sm font-medium text-gray-300">
                    <input type="checkbox" id="add-separator" class="w-4 h-4 rounded text-indigo-600 bg-gray-700 border-gray-600 focus:ring-indigo-500">
                    Draw a separator line between pages
                </label>
            </div>
            <button id="process-btn" class="btn-gradient w-full mt-6">Combine Pages</button>
        </div>
    `,

  'fix-dimensions': () => `
        <h2 class="text-2xl font-bold text-white mb-4">Standardize Page Dimensions</h2>
        <p class="mb-6 text-gray-400">Convert all pages in your PDF to a uniform size. Choose a standard format or define a custom dimension.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>

        <div id="fix-dimensions-options" class="hidden mt-6 space-y-4">
            <div class="grid grid-cols-1 sm:grid-cols-2 gap-4">
                <div>
                    <label for="target-size" class="block mb-2 text-sm font-medium text-gray-300">Target Size</label>
                    <select id="target-size" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
                        <option value="A4" selected>A4</option>
                        <option value="Letter">Letter</option>
                        <option value="Legal">Legal</option>
                        <option value="Tabloid">Tabloid</option>
                        <option value="A3">A3</option>
                        <option value="A5">A5</option>
                        <option value="Custom">Custom Size...</option>
                    </select>
                </div>
                <div>
                    <label for="orientation" class="block mb-2 text-sm font-medium text-gray-300">Orientation</label>
                    <select id="orientation" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
                        <option value="portrait" selected>Portrait</option>
                        <option value="landscape">Landscape</option>
                    </select>
                </div>
            </div>

            <div id="custom-size-wrapper" class="hidden p-4 rounded-lg bg-gray-900 border border-gray-700 grid grid-cols-3 gap-3">
                <div>
                    <label for="custom-width" class="block mb-2 text-xs font-medium text-gray-300">Width</label>
                    <input type="number" id="custom-width" value="8.5" class="w-full bg-gray-700 border-gray-600 text-white rounded-lg p-2">
                </div>
                <div>
                    <label for="custom-height" class="block mb-2 text-xs font-medium text-gray-300">Height</label>
                    <input type="number" id="custom-height" value="11" class="w-full bg-gray-700 border-gray-600 text-white rounded-lg p-2">
                </div>
                <div>
                    <label for="custom-units" class="block mb-2 text-xs font-medium text-gray-300">Units</label>
                    <select id="custom-units" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2">
                        <option value="in">Inches</option>
                        <option value="mm">Millimeters</option>
                    </select>
                </div>
            </div>

            <div>
                <label class="block mb-2 text-sm font-medium text-gray-300">Content Scaling Method</label>
                <div class="flex gap-4 p-2 rounded-lg bg-gray-900">
                    <label class="flex-1 flex items-center gap-2 p-3 rounded-md hover:bg-gray-700 cursor-pointer">
                        <input type="radio" name="scaling-mode" value="fit" checked class="w-4 h-4 text-indigo-600 bg-gray-700 border-gray-600 focus:ring-indigo-500">
                        <div>
                            <span class="font-semibold text-white">Fit</span>
                            <p class="text-xs text-gray-400">Preserves all content, may add white bars.</p>
                        </div>
                    </label>
                    <label class="flex-1 flex items-center gap-2 p-3 rounded-md hover:bg-gray-700 cursor-pointer">
                        <input type="radio" name="scaling-mode" value="fill" class="w-4 h-4 text-indigo-600 bg-gray-700 border-gray-600 focus:ring-indigo-500">
                         <div>
                            <span class="font-semibold text-white">Fill</span>
                            <p class="text-xs text-gray-400">Covers the page, may crop content.</p>
                        </div>
                    </label>
                </div>
            </div>

             <div>
                <label for="background-color" class="block mb-2 text-sm font-medium text-gray-300">Background Color (for 'Fit' mode)</label>
                <input type="color" id="background-color" value="#FFFFFF" class="w-full h-[42px] bg-gray-700 border border-gray-600 rounded-lg p-1 cursor-pointer">
            </div>

            <button id="process-btn" class="btn-gradient w-full mt-6">Standardize Pages</button>
        </div>
    `,

  'change-background-color': () => `
        <h2 class="text-2xl font-bold text-white mb-4">Change Background Color</h2>
        <p class="mb-6 text-gray-400">Select a new background color for every page of your PDF.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <div id="change-background-color-options" class="hidden mt-6">
            <label for="background-color" class="block mb-2 text-sm font-medium text-gray-300">Choose Background Color</label>
            <input type="color" id="background-color" value="#FFFFFF" class="w-full h-[42px] bg-gray-700 border border-gray-600 rounded-lg p-1 cursor-pointer">
            <button id="process-btn" class="btn-gradient w-full mt-6">Apply Color & Download</button>
        </div>
    `,

  'change-text-color': () => `
        <h2 class="text-2xl font-bold text-white mb-4">Change Text Color</h2>
        <p class="mb-6 text-gray-400">Change the color of dark text in your PDF. This process converts pages to images, so text will not be selectable in the final file.</p>
        ${createFileInputHTML()}
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <div id="text-color-options" class="hidden mt-6 space-y-4">
            <div>
                <label for="text-color-input" class="block mb-2 text-sm font-medium text-gray-300">Select Text Color</label>
                <input type="color" id="text-color-input" value="#FF0000" class="w-full h-[42px] bg-gray-700 border border-gray-600 rounded-lg p-1 cursor-pointer">
            </div>
            <div class="grid grid-cols-2 gap-4">
                <div class="text-center">
                    <h3 class="font-semibold text-white mb-2">Original</h3>
                    <canvas id="original-canvas" class="w-full h-auto rounded-lg border-2 border-gray-600"></canvas>
                </div>
                <div class="text-center">
                    <h3 class="font-semibold text-white mb-2">Preview</h3>
                    <canvas id="text-color-canvas" class="w-full h-auto rounded-lg border-2 border-gray-600"></canvas>
                </div>
            </div>
            <button id="process-btn" class="btn-gradient w-full mt-6">Apply Color & Download</button>
        </div>
    `,

  'compare-pdfs': () => `
        <h2 class="text-2xl font-bold text-white mb-4">Compare PDFs</h2>
        <p class="mb-6 text-gray-400">Upload two files to visually compare them using either an overlay or a side-by-side view.</p>
        
        <div id="compare-upload-area" class="grid grid-cols-1 md:grid-cols-2 gap-4">
            <div id="drop-zone-1" class="relative flex flex-col items-center justify-center w-full h-48 border-2 border-dashed border-gray-600 rounded-xl cursor-pointer bg-gray-900 hover:bg-gray-700">
                <div id="file-display-1" class="flex flex-col items-center justify-center pt-5 pb-6">
                    <i data-lucide="file-scan" class="w-10 h-10 mb-3 text-gray-400"></i>
                    <p class="mb-2 text-sm text-gray-400"><span class="font-semibold">Upload Original PDF</span></p>
                </div>
                <input id="file-input-1" type="file" class="absolute top-0 left-0 w-full h-full opacity-0 cursor-pointer" accept="application/pdf">
            </div>
            <div id="drop-zone-2" class="relative flex flex-col items-center justify-center w-full h-48 border-2 border-dashed border-gray-600 rounded-xl cursor-pointer bg-gray-900 hover:bg-gray-700">
                <div id="file-display-2" class="flex flex-col items-center justify-center pt-5 pb-6">
                    <i data-lucide="file-diff" class="w-10 h-10 mb-3 text-gray-400"></i>
                    <p class="mb-2 text-sm text-gray-400"><span class="font-semibold">Upload Revised PDF</span></p>
                </div>
                <input id="file-input-2" type="file" class="absolute top-0 left-0 w-full h-full opacity-0 cursor-pointer" accept="application/pdf">
            </div>
        </div>

        <div id="compare-viewer" class="hidden mt-6">
            <div class="flex flex-wrap items-center justify-center gap-4 mb-4 p-3 bg-gray-900 rounded-lg border border-gray-700">
                <button id="prev-page-compare" class="btn p-2 rounded-full bg-gray-700 hover:bg-gray-600 disabled:opacity-50"><i data-lucide="chevron-left"></i></button>
                <span class="text-white font-medium">Page <span id="current-page-display-compare">1</span> of <span id="total-pages-display-compare">1</span></span>
                <button id="next-page-compare" class="btn p-2 rounded-full bg-gray-700 hover:bg-gray-600 disabled:opacity-50"><i data-lucide="chevron-right"></i></button>
                <div class="border-l border-gray-600 h-6 mx-2"></div>
                <div class="bg-gray-700 p-1 rounded-md flex gap-1">
                    <button id="view-mode-overlay" class="btn bg-indigo-600 px-3 py-1 rounded text-sm font-semibold">Overlay</button>
                    <button id="view-mode-side" class="btn px-3 py-1 rounded text-sm font-semibold">Side-by-Side</button>
                </div>
                <div class="border-l border-gray-600 h-6 mx-2"></div>
                <div id="overlay-controls" class="flex items-center gap-2">
                    <button id="flicker-btn" class="btn bg-gray-700 hover:bg-gray-600 px-3 py-1 rounded-md text-sm font-semibold">Flicker</button>
                    <label for="opacity-slider" class="text-sm font-medium text-gray-300">Opacity:</label>
                    <input type="range" id="opacity-slider" min="0" max="1" step="0.05" value="0.5" class="w-24">
                </div>
                <div id="side-by-side-controls" class="hidden flex items-center gap-2">
                    <label class="flex items-center gap-2 text-sm font-medium text-gray-300 cursor-pointer">
                        <input type="checkbox" id="sync-scroll-toggle" checked class="w-4 h-4 rounded text-indigo-600 bg-gray-700 border-gray-600 focus:ring-indigo-500">
                        Sync Scrolling
                    </label>
                </div>
            </div>
            <div id="compare-viewer-wrapper" class="compare-viewer-wrapper overlay-mode">
                <div id="panel-1" class="pdf-panel"><canvas id="canvas-compare-1"></canvas></div>
                <div id="panel-2" class="pdf-panel"><canvas id="canvas-compare-2"></canvas></div>
            </div>
        </div>
    `,

  'ocr-pdf': () => `
    <h2 class="text-2xl font-bold text-white mb-4">OCR PDF</h2>
    <p class="mb-6 text-gray-400">Convert scanned PDFs into searchable documents. Select one or more languages present in your file for the best results.</p>
    ${createFileInputHTML()}
    <div id="file-display-area" class="mt-4 space-y-2"></div>
    
    <div id="ocr-options" class="hidden mt-6 space-y-4">
        <div>
            <label class="block mb-2 text-sm font-medium text-gray-300">Languages in Document</label>
            <div class="relative">
                <input type="text" id="lang-search" class="w-full bg-gray-900 border border-gray-600 text-white rounded-lg p-2.5 mb-2" placeholder="Search for languages...">
                <div id="lang-list" class="max-h-48 overflow-y-auto border border-gray-600 rounded-lg p-2 bg-gray-900">
                    ${Object.entries(tesseractLanguages)
                      .map(
                        ([code, name]) => `
                        <label class="flex items-center gap-2 p-2 rounded-md hover:bg-gray-700 cursor-pointer">
                            <input type="checkbox" value="${code}" class="lang-checkbox w-4 h-4 rounded text-indigo-600 bg-gray-700 border-gray-600 focus:ring-indigo-500">
                            ${name}
                        </label>
                    `
                      )
                      .join('')}
                </div>
            </div>
             <p class="text-xs text-gray-500 mt-1">Selected: <span id="selected-langs-display" class="font-semibold">None</span></p>
        </div>
        
        <!-- Advanced settings section -->
        <details class="bg-gray-900 border border-gray-700 rounded-lg p-3">
            <summary class="text-sm font-medium text-gray-300 cursor-pointer">Advanced Settings</summary>
            <div class="mt-4 space-y-4">
                <!-- Resolution Setting -->
                <div>
                    <label for="ocr-resolution" class="block mb-1 text-xs font-medium text-gray-400">Resolution</label>
                    <select id="ocr-resolution" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2 text-sm">
                        <option value="2.0">Standard (192 DPI)</option>
                        <option value="3.0" selected>High (288 DPI)</option>
                        <option value="4.0">Ultra (384 DPI)</option>
                    </select>
                </div>
                <!-- Binarization Toggle -->
                <label class="flex items-center gap-2 text-sm text-gray-300 cursor-pointer">
                    <input type="checkbox" id="ocr-binarize" class="w-4 h-4 rounded text-indigo-600 bg-gray-700 border-gray-600">
                    Binarize Image (Enhance Contrast for Clean Scans)
                </label>
                <!-- Character Whitelist -->
                <div>
                    <label for="ocr-whitelist" class="block mb-1 text-xs font-medium text-gray-400">Character Whitelist (Optional)</label>
                    <input type="text" id="ocr-whitelist" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2 text-sm" placeholder="e.g., abcdefghijklmnopqrstuvwxyz0123456789$.,">
                </div>
            </div>
        </details>
        
        <button id="process-btn" class="btn-gradient w-full disabled:opacity-50" disabled>Start OCR</button>
    </div>

    <div id="ocr-progress" class="hidden mt-6 p-4 bg-gray-900 border border-gray-700 rounded-lg">
        <p id="progress-status" class="text-white mb-2">Initializing...</p>
        <div class="w-full bg-gray-700 rounded-full h-4">
            <div id="progress-bar" class="bg-indigo-600 h-4 rounded-full transition-width duration-300" style="width: 0%"></div>
        </div>
        <pre id="progress-log" class="mt-4 text-xs text-gray-400 max-h-32 overflow-y-auto bg-black p-2 rounded-md"></pre>
    </div>

    <div id="ocr-results" class="hidden mt-6">
        <h3 class="text-xl font-bold text-white mb-2">OCR Complete</h3>
        <p class="mb-4 text-gray-400">Your searchable PDF is ready. You can also copy or download the extracted text below.</p>
        <div class="relative">
            <textarea id="ocr-text-output" rows="10" class="w-full bg-gray-900 border border-gray-600 text-gray-300 rounded-lg p-2.5 font-sans" readonly></textarea>
            <button id="copy-text-btn" class="absolute top-2 right-2 btn bg-gray-700 hover:bg-gray-600 p-2 rounded-md" title="Copy to Clipboard">
                <i data-lucide="clipboard-copy" class="w-4 h-4 text-gray-300"></i>
            </button>
        </div>
        <div class="grid grid-cols-1 sm:grid-cols-2 gap-4 mt-4">
            <button id="download-txt-btn" class="btn w-full bg-gray-700 text-white font-semibold py-3 rounded-lg hover:bg-gray-600">Download as .txt</button>
            <button id="download-searchable-pdf" class="btn w-full bg-green-600 text-white font-semibold py-3 rounded-lg hover:bg-green-700">Download Searchable PDF</button>
        </div>
    </div>
`,

  'word-to-pdf': () => `
        <h2 class="text-2xl font-bold text-white mb-4">Word to PDF Converter</h2>
        <p class="mb-6 text-gray-400">Upload a .docx file to convert it into a high-quality PDF with selectable text. Complex layouts may not be perfectly preserved.</p>
        
        <div id="file-input-wrapper">
             <div class="relative flex flex-col items-center justify-center w-full h-48 border-2 border-dashed border-gray-600 rounded-xl cursor-pointer bg-gray-900 hover:bg-gray-700">
                <div class="flex flex-col items-center justify-center pt-5 pb-6">
                    <i data-lucide="file-text" class="w-10 h-10 mb-3 text-gray-400"></i>
                    <p class="mb-2 text-sm text-gray-400"><span class="font-semibold">Click to select a file</span> or drag and drop</p>
                    <p class="text-xs text-gray-500">A single .docx file</p>
                </div>
                <input id="file-input" type="file" class="absolute top-0 left-0 w-full h-full opacity-0 cursor-pointer" accept=".docx,application/vnd.openxmlformats-officedocument.wordprocessingml.document">
            </div>
        </div>
        
        <div id="file-display-area" class="mt-4 space-y-2"></div>
        <button id="process-btn" class="btn-gradient w-full mt-6" disabled>Preview & Convert</button>
    `,

  'sign-pdf': () => `
    <h2 class="text-2xl font-bold text-white mb-4">Sign PDF</h2>
    <p class="mb-6 text-gray-400">Create your signature, select it, then click on the document to place. You can drag to move placed signatures.</p>
    ${createFileInputHTML()}
    
    <div id="signature-editor" class="hidden mt-6">
        <div class="bg-gray-900 p-4 rounded-lg border border-gray-700 mb-4">
            <div class="flex border-b border-gray-700 mb-4">
                <button id="draw-tab-btn" class="flex-1 p-2 text-sm font-semibold border-b-2 border-indigo-500 text-white">Draw</button>
                <button id="type-tab-btn" class="flex-1 p-2 text-sm font-semibold border-b-2 border-transparent text-gray-400">Type</button>
                <button id="upload-tab-btn" class="flex-1 p-2 text-sm font-semibold border-b-2 border-transparent text-gray-400">Upload</button>
            </div>
            
            <div id="draw-panel">
                <canvas id="signature-draw-canvas" class="bg-white rounded-md cursor-crosshair w-full" height="150"></canvas>
                
                <div class="flex flex-col sm:flex-row sm:justify-between sm:items-center mt-2 gap-4 sm:gap-2">
                    <div class="flex items-center gap-2">
                        <label for="signature-color" class="text-sm font-medium text-gray-300">Color:</label>
                        <input type="color" id="signature-color" value="#22c55e" class="w-10 h-10 bg-gray-700 border border-gray-600 rounded-lg p-1 cursor-pointer">
                    </div>
                    <div class="flex items-center gap-2">
                        <button id="clear-draw-btn" class="btn hover:bg-gray-600 text-sm flex-grow sm:flex-grow-0">Clear</button>
                        <button id="save-draw-btn" class="btn-gradient px-4 py-2 text-sm rounded-lg flex-grow sm:flex-grow-0">Save Signature</button>
                    </div>
                </div>
            </div>

            <div id="type-panel" class="hidden">
                <input type="text" id="signature-text-input" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5 mb-4" placeholder="Type your name here">
                
                <div class="grid grid-cols-1 sm:grid-cols-3 gap-4 mb-4">
                    <div>
                        <label for="font-family-select" class="block mb-1 text-xs font-medium text-gray-400">Font Style</label>
                        <select id="font-family-select" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2 text-sm">
                            <option value="'Great Vibes', cursive">Signature</option>
                            <option value="'Kalam', cursive">Handwritten</option>
                            <option value="'Dancing Script', cursive">Script</option>
                            <option value="'Lato', sans-serif">Regular</option>
                            <option value="'Merriweather', serif">Formal</option>
                        </select>
                    </div>
                     <div>
                        <label for="font-size-slider" class="block mb-1 text-xs font-medium text-gray-400">Font Size (<span id="font-size-value">48</span>px)</label>
                        <input type="range" id="font-size-slider" min="24" max="72" value="32" class="w-full">
                    </div>
                    <div>
                        <label for="font-color-picker" class="block mb-1 text-xs font-medium text-gray-400">Color</label>
                        <input type="color" id="font-color-picker" value="#22c55e" class="w-full h-[38px] bg-gray-700 border border-gray-600 rounded-lg p-1 cursor-pointer">
                    </div>
                </div>

                <div id="font-preview" class="p-4 h-[80px] bg-transparent rounded-md flex items-center justify-center text-4xl" style="font-family: 'Great Vibes', cursive; font-size: 32px; color: #22c55e;">Your Name</div>
                 
                <div class="flex justify-end mt-4">
                    <button id="save-type-btn" class="btn-gradient px-4 py-2 text-sm rounded-lg">Save Signature</button>
                </div>
            </div>

            <div id="upload-panel" class="hidden">
                <input type="file" id="signature-upload-input" accept="image/png" class="w-full text-sm text-gray-400 file:mr-4 file:py-2 file:px-4 file:rounded-lg file:border-0 file:text-sm file:font-semibold file:bg-indigo-600 file:text-white hover:file:bg-indigo-700">
                *png files only
            </div>
            
            <hr class="border-gray-700 my-4">
            <h4 class="text-md font-semibold text-white mb-2">Your Saved Signatures</h4>
            <div id="saved-signatures-container" class="flex flex-wrap gap-2 bg-gray-800 p-2 rounded-md min-h-[50px]">
                <p class="text-xs text-gray-500 text-center w-full">Your saved signatures will appear here. Click one to select it.</p>
            </div>
        </div>

        <div class="flex flex-wrap items-center justify-center gap-4 mb-4 p-3 bg-gray-900 rounded-lg border border-gray-700">
            <button id="prev-page-sign" class="btn p-2 rounded-full bg-gray-700 hover:bg-gray-600 disabled:opacity-50"><i data-lucide="chevron-left"></i></button>
            <span class="text-white font-medium">Page <span id="current-page-display-sign">1</span> of <span id="total-pages-display-sign">1</span></span>
            <button id="next-page-sign" class="btn p-2 rounded-full bg-gray-700 hover:bg-gray-600 disabled:opacity-50"><i data-lucide="chevron-right"></i></button>
            <div class="border-l border-gray-600 h-6 mx-2 hidden sm:block"></div>
            <button id="zoom-out-btn" class="btn p-2 rounded-full bg-gray-700 hover:bg-gray-600"><i data-lucide="zoom-out"></i></button>
            <button id="fit-width-btn" class="btn p-2 rounded-full bg-gray-700 hover:bg-gray-600"><i data-lucide="minimize"></i></button>
            <button id="zoom-in-btn" class="btn p-2 rounded-full bg-gray-700 hover:bg-gray-600"><i data-lucide="zoom-in"></i></button>
            <div class="border-l border-gray-600 h-6 mx-2 hidden sm:block"></div>
            <button id="undo-btn" class="btn p-2 rounded-full" title="Undo Last Placement"><i data-lucide="undo-2"></i></button>
        </div>

        <div id="canvas-container-sign" class="relative w-full overflow-auto bg-gray-900 rounded-lg border border-gray-600 h-[60vh] md:h-[80vh]">
            <canvas id="canvas-sign" class="mx-auto"></canvas>
        </div>

    </div>
    <button id="process-btn" class="hidden btn-gradient w-full mt-6">Apply Signatures & Download PDF</button>
`,

  'remove-annotations': () => `
    <h2 class="text-2xl font-bold text-white mb-4">Remove Annotations</h2>
    <p class="mb-6 text-gray-400">Select the types of annotations to remove from all pages or a specific range.</p>
    ${createFileInputHTML()}
    <div id="file-display-area" class="mt-4 space-y-2"></div>

    <div id="remove-annotations-options" class="hidden mt-6 space-y-6">
        <div>
            <h3 class="text-lg font-semibold text-white mb-2">1. Choose Pages</h3>
            <div class="flex gap-4 p-2 rounded-lg bg-gray-900">
                <label class="flex-1 flex items-center gap-2 p-3 rounded-md hover:bg-gray-700 cursor-pointer">
                    <input type="radio" name="page-scope" value="all" checked class="w-4 h-4 text-indigo-600 bg-gray-700 border-gray-600 focus:ring-indigo-500">
                    <span class="font-semibold text-white">All Pages</span>
                </label>
                <label class="flex-1 flex items-center gap-2 p-3 rounded-md hover:bg-gray-700 cursor-pointer">
                    <input type="radio" name="page-scope" value="specific" class="w-4 h-4 text-indigo-600 bg-gray-700 border-gray-600 focus:ring-indigo-500">
                    <span class="font-semibold text-white">Specific Pages</span>
                </label>
            </div>
            <div id="page-range-wrapper" class="hidden mt-2">
                 <input type="text" id="page-range-input" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5" placeholder="e.g., 1-3, 5, 8">
                 <p class="text-xs text-gray-400 mt-1">Total Pages: <span id="total-pages"></span></p>
            </div>
        </div>

        <div>
            <h3 class="text-lg font-semibold text-white mb-2">2. Select Annotation Types to Remove</h3>
            <div class="space-y-3 p-4 bg-gray-900 rounded-lg border border-gray-700">
                <div class="border-b border-gray-700 pb-2">
                    <label class="flex items-center gap-2 font-semibold text-white cursor-pointer">
                        <input type="checkbox" id="select-all-annotations" class="w-4 h-4 rounded text-indigo-600 bg-gray-700 border-gray-600">
                        Select / Deselect All
                    </label>
                </div>
                <div class="grid grid-cols-2 sm:grid-cols-3 gap-x-4 gap-y-2 pt-2">
                    <label class="flex items-center gap-2"><input type="checkbox" class="annot-checkbox" value="Highlight"> Highlight</label>
                    <label class="flex items-center gap-2"><input type="checkbox" class="annot-checkbox" value="StrikeOut"> Strikeout</label>
                    <label class="flex items-center gap-2"><input type="checkbox" class="annot-checkbox" value="Underline"> Underline</label>
                    <label class="flex items-center gap-2"><input type="checkbox" class="annot-checkbox" value="Ink"> Ink / Draw</label>
                    <label class="flex items-center gap-2"><input type="checkbox" class="annot-checkbox" value="Polygon"> Polygon</label>
                    <label class="flex items-center gap-2"><input type="checkbox" class="annot-checkbox" value="Square"> Square</label>
                    <label class="flex items-center gap-2"><input type="checkbox" class="annot-checkbox" value="Circle"> Circle</label>
                    <label class="flex items-center gap-2"><input type="checkbox" class="annot-checkbox" value="Line"> Line / Arrow</label>
                    <label class="flex items-center gap-2"><input type="checkbox" class="annot-checkbox" value="PolyLine"> Polyline</label>
                    <label class="flex items-center gap-2"><input type="checkbox" class="annot-checkbox" value="Link"> Link</label>
                    <label class="flex items-center gap-2"><input type="checkbox" class="annot-checkbox" value="Text"> Text (Note)</label>
                    <label class="flex items-center gap-2"><input type="checkbox" class="annot-checkbox" value="FreeText"> Free Text</label>
                    <label class="flex items-center gap-2"><input type="checkbox" class="annot-checkbox" value="Popup"> Popup / Comment</label>
                    <label class="flex items-center gap-2"><input type="checkbox" class="annot-checkbox" value="Squiggly"> Squiggly</label>
                    <label class="flex items-center gap-2"><input type="checkbox" class="annot-checkbox" value="Stamp"> Stamp</label>
                    <label class="flex items-center gap-2"><input type="checkbox" class="annot-checkbox" value="Caret"> Caret</label>
                    <label class="flex items-center gap-2"><input type="checkbox" class="annot-checkbox" value="FileAttachment"> File Attachment</label>    
                </div>
            </div>
        </div>
    </div>
    <button id="process-btn" class="hidden btn-gradient w-full mt-6">Remove Selected Annotations</button>
`,

  cropper: () => `
    <h2 class="text-2xl font-bold text-white mb-4">PDF Cropper</h2>
    <p class="mb-6 text-gray-400">Upload a PDF to visually crop one or more pages. This tool offers a live preview and two distinct cropping modes.</p>
    
    ${createFileInputHTML()}
    <div id="file-display-area" class="mt-4 space-y-2"></div>
    
    <div id="cropper-ui-container" class="hidden mt-6">
        
        <div class="p-3 bg-gray-900 rounded-lg border border-gray-700 mb-6">
            <p class="text-sm text-gray-300"><strong class="text-white">How it works:</strong></p>
            <ul class="list-disc list-inside text-xs text-gray-400 mt-1 space-y-1">
                <li><strong class="text-white">Live Preview:</strong> See your crop selection in real-time before you apply it.</li>
                <li><strong class="text-white">Non-Destructive Mode:</strong> This is the default mode. It simply "hides" the cropped content by adjusting the page's boundaries. The original text and data are preserved in the file.</li>
                <li><strong class="text-white">Destructive Mode:</strong> This option permanently removes the cropped content by flattening the PDF. Use this for maximum security and smaller file size, but note that it will remove selectable text.</li>
            </ul>
        </div>
        
        <div class="flex flex-col sm:flex-row items-center justify-between flex-wrap gap-4 mb-4 p-3 bg-gray-900 rounded-lg border border-gray-700">
            <div class="flex items-center gap-2">
                 <button id="prev-page" class="btn p-2 rounded-full bg-gray-700 hover:bg-gray-600 disabled:opacity-50"><i data-lucide="chevron-left" class="w-5 h-5"></i></button>
                <span id="page-info" class="text-white font-medium">Page 0 of 0</span>
                <button id="next-page" class="btn p-2 rounded-full bg-gray-700 hover:bg-gray-600 disabled:opacity-50"><i data-lucide="chevron-right" class="w-5 h-5"></i></button>
            </div>
            
            <div class="flex flex-col sm:flex-row items-center gap-4 flex-wrap">
                 <label class="flex items-center gap-2 text-sm font-medium text-gray-300">
                    <input type="checkbox" id="destructive-crop-toggle" class="w-4 h-4 rounded text-indigo-600 bg-gray-700 border-gray-600 focus:ring-indigo-500">
                    Enable Destructive Crop
                </label>
                 <label class="flex items-center gap-2 text-sm font-medium text-gray-300">
                    <input type="checkbox" id="apply-to-all-toggle" class="w-4 h-4 rounded text-indigo-600 bg-gray-700 border-gray-600 focus:ring-indigo-500">
                    Apply to all pages
                </label>
            </div>
        </div>
        
        <div id="status" class="text-center italic text-gray-400 mb-4">Please select a PDF file to begin.</div>
        <div id="cropper-container" class="w-full relative overflow-hidden flex items-center justify-center bg-gray-900 rounded-lg border border-gray-600 min-h-[500px]"></div>
        
        <button id="crop-button" class="btn-gradient w-full mt-6" disabled>Crop & Download</button>
    </div>
`,

  'form-filler': () => `
    <h2 class="text-2xl font-bold text-white mb-4">PDF Form Filler</h2>
    <p class="mb-6 text-gray-400">Upload a PDF to fill in existing form fields. The PDF view on the right will update as you type.</p>
    ${createFileInputHTML()}
    <div id="file-display-area" class="mt-4 space-y-2"></div>
    <div id="form-filler-options" class="hidden mt-6">
        <div class="flex flex-col lg:flex-row gap-4 h-[80vh]">
            
            <!-- Sidebar for form fields -->
            <div class="w-full lg:w-1/3 bg-gray-900 rounded-lg p-4 overflow-y-auto border border-gray-700 flex-shrink-0">
                <div id="form-fields-container" class="space-y-4">
                    <div class="p-4 text-center text-gray-400">
                        <p>Upload a file to see form fields here.</p>
                    </div>
                </div>
            </div>

            <!-- PDF Viewer -->
            <div class="w-full lg:w-2/3 flex flex-col items-center gap-4">
                <div class="flex flex-nowrap items-center justify-center gap-4 p-3 bg-gray-900 rounded-lg border border-gray-700">
                    <button id="prev-page" class="btn p-2 rounded-full bg-gray-700 hover:bg-gray-600 disabled:opacity-50">
                        <i data-lucide="chevron-left" class="w-5 h-5"></i>
                    </button>
                    <span class="text-white font-medium">
                        Page <span id="current-page-display">1</span> of <span id="total-pages-display">1</span>
                    </span>
                    <button id="next-page" class="btn p-2 rounded-full bg-gray-700 hover:bg-gray-600 disabled:opacity-50">
                        <i data-lucide="chevron-right" class="w-5 h-5"></i>
                    </button>
                    <button id="zoom-out-btn" class="btn p-2 rounded-full bg-gray-700 hover:bg-gray-600">
                        <i data-lucide="zoom-out"></i>
                    </button>
                    <button id="zoom-in-btn" class="btn p-2 rounded-full bg-gray-700 hover:bg-gray-600">
                        <i data-lucide="zoom-in"></i>
                    </button>
                </div>

                <div id="pdf-viewer-container" class="relative w-full overflow-auto bg-gray-900 rounded-lg border border-gray-600 flex-grow">
                    <canvas id="pdf-canvas" class="mx-auto max-w-full h-full"></canvas>
                </div>
            </div>
        </div>
        
        <button id="process-btn" class="btn-gradient w-full mt-6 hidden">Save & Download</button>
    </div>
`,

  posterize: () => `
    <h2 class="text-2xl font-bold text-white mb-4">Posterize PDF</h2>
    <p class="mb-6 text-gray-400">Split pages into multiple smaller sheets to print as a poster. Navigate the preview and see the grid update based on your settings.</p>
    ${createFileInputHTML()}
    <div id="file-display-area" class="mt-4 space-y-2"></div>

    <div id="posterize-options" class="hidden mt-6 space-y-6">

        <div class="space-y-2">
             <label class="block text-sm font-medium text-gray-300">Page Preview (<span id="current-preview-page">1</span> / <span id="total-preview-pages">1</span>)</label>
            <div id="posterize-preview-container" class="relative w-full max-w-xl mx-auto bg-gray-900 rounded-lg border-2 border-gray-600 flex items-center justify-center">
                <button id="prev-preview-page" class="absolute left-2 top-1/2 transform -translate-y-1/2 text-white bg-gray-800 bg-opacity-50 rounded-full p-2 hover:bg-gray-700 disabled:opacity-50 z-10"><i data-lucide="chevron-left"></i></button>
                <canvas id="posterize-preview-canvas" class="w-full h-auto rounded-md"></canvas>
                <button id="next-preview-page" class="absolute right-2 top-1/2 transform -translate-y-1/2 text-white bg-gray-800 bg-opacity-50 rounded-full p-2 hover:bg-gray-700 disabled:opacity-50 z-10"><i data-lucide="chevron-right"></i></button>
            </div>
        </div>

        <div class="p-4 bg-gray-900 border border-gray-700 rounded-lg">
            <h3 class="text-lg font-semibold text-white mb-3">Grid Layout</h3>
            <div class="grid grid-cols-1 sm:grid-cols-2 gap-4">
                <div>
                    <label for="posterize-rows" class="block mb-2 text-sm font-medium text-gray-300">Rows</label>
                    <input type="number" id="posterize-rows" value="1" min="1" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
                </div>
                <div>
                    <label for="posterize-cols" class="block mb-2 text-sm font-medium text-gray-300">Columns</label>
                    <input type="number" id="posterize-cols" value="2" min="1" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
                </div>
            </div>
        </div>

        <div class="p-4 bg-gray-900 border border-gray-700 rounded-lg">
            <h3 class="text-lg font-semibold text-white mb-3">Output Page Settings</h3>
            <div class="grid grid-cols-1 sm:grid-cols-2 gap-4">
                <div>
                    <label for="output-page-size" class="block mb-2 text-sm font-medium text-gray-300">Page Size</label>
                    <select id="output-page-size" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
                        <option value="A4" selected>A4</option>
                        <option value="Letter">Letter</option>
                        <option value="Legal">Legal</option>
                        <option value="A3">A3</option>
                        <option value="A5">A5</option>
                    </select>
                </div>
                <div>
                    <label for="output-orientation" class="block mb-2 text-sm font-medium text-gray-300">Orientation</label>
                    <select id="output-orientation" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
                        <option value="auto" selected>Automatic (Recommended)</option>
                        <option value="portrait">Portrait</option>
                        <option value="landscape">Landscape</option>
                    </select>
                </div>
            </div>
        </div>

        <div class="p-4 bg-gray-900 border border-gray-700 rounded-lg">
            <h3 class="text-lg font-semibold text-white mb-3">Advanced Options</h3>
            <div class="space-y-4">
                <div>
                    <label class="block mb-2 text-sm font-medium text-gray-300">Content Scaling</label>
                    <div class="flex gap-4 p-2 rounded-lg bg-gray-800">
                        <label class="flex-1 flex items-center gap-2 p-3 rounded-md hover:bg-gray-700 cursor-pointer has-[:checked]:bg-indigo-600">
                            <input type="radio" name="scaling-mode" value="fit" checked class="w-4 h-4 text-indigo-600 bg-gray-700 border-gray-600 focus:ring-indigo-500">
                            <div>
                                <span class="font-semibold text-white">Fit</span>
                                <p class="text-xs text-gray-400">Preserves all content, may add margins.</p>
                            </div>
                        </label>
                        <label class="flex-1 flex items-center gap-2 p-3 rounded-md hover:bg-gray-700 cursor-pointer has-[:checked]:bg-indigo-600">
                            <input type="radio" name="scaling-mode" value="fill" class="w-4 h-4 text-indigo-600 bg-gray-700 border-gray-600 focus:ring-indigo-500">
                             <div>
                                <span class="font-semibold text-white">Fill (Crop)</span>
                                <p class="text-xs text-gray-400">Fills the page, may crop content.</p>
                            </div>
                        </label>
                    </div>
                </div>
                 <div>
                    <label for="overlap" class="block mb-2 text-sm font-medium text-gray-300">Overlap (for assembly)</label>
                    <div class="flex items-center gap-2">
                        <input type="number" id="overlap" value="0" min="0" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
                        <select id="overlap-units" class="bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5">
                            <option value="pt">Points</option>
                            <option value="in">Inches</option>
                            <option value="mm">mm</option>
                        </select>
                    </div>
                </div>
                 <div>
                    <label for="page-range" class="block mb-2 text-sm font-medium text-gray-300">Page Range (optional)</label>
                    <input type="text" id="page-range" class="w-full bg-gray-700 border border-gray-600 text-white rounded-lg p-2.5" placeholder="e.g., 1-3, 5">
                    <p class="text-xs text-gray-400 mt-1">Total pages: <span id="total-pages">0</span></p>
                </div>
            </div>
        </div>

        <button id="process-btn" class="btn-gradient w-full mt-6" disabled>Posterize PDF</button>
    </div>
`,

  'remove-blank-pages': () => `
    <h2 class="text-2xl font-bold text-white mb-4">Remove Blank Pages</h2>
    <p class="mb-6 text-gray-400">Automatically detect and remove blank or nearly blank pages from your PDF. Adjust the sensitivity to control what is considered "blank".</p>
    ${createFileInputHTML()}
    <div id="file-display-area" class="mt-4 space-y-2"></div>

    <div id="remove-blank-options" class="hidden mt-6 space-y-4">
        <div>
            <label for="sensitivity-slider" class="block mb-2 text-sm font-medium text-gray-300">
                Sensitivity (<span id="sensitivity-value">99</span>%)
            </label>
            <input type="range" id="sensitivity-slider" min="80" max="100" value="99" class="w-full">
            <p class="text-xs text-gray-400 mt-1">Higher sensitivity requires pages to be more "blank" to be removed.</p>
        </div>
        
        <div id="analysis-preview" class="hidden p-4 bg-gray-900 border border-gray-700 rounded-lg">
             <h3 class="text-lg font-semibold text-white mb-2">Analysis Results</h3>
             <p id="analysis-text" class="text-gray-300"></p>
             <div id="removed-pages-thumbnails" class="mt-4 grid grid-cols-5 sm:grid-cols-8 md:grid-cols-10 gap-2"></div>
        </div>

        <button id="process-btn" class="btn-gradient w-full mt-6">Remove Blank Pages & Download</button>
    </div>
`,

  'alternate-merge': () => `
    <h2 class="text-2xl font-bold text-white mb-4">Alternate & Mix Pages</h2>
    <p class="mb-6 text-gray-400">Combine pages from 2 or more documents, alternating between them. Drag the files to set the mixing order (e.g., Page 1 from Doc A, Page 1 from Doc B, Page 2 from Doc A, Page 2 from Doc B, etc.).</p>
    ${createFileInputHTML({ multiple: true, accept: 'application/pdf', showControls: true })}
    
    <div id="alternate-merge-options" class="hidden mt-6">
        <div class="p-3 bg-gray-900 rounded-lg border border-gray-700 mb-3">
            <p class="text-sm text-gray-300"><strong class="text-white">How it works:</strong></p>
            <ul class="list-disc list-inside text-xs text-gray-400 mt-1 space-y-1">
                <li>The tool will take one page from each document in the order you specify below, then repeat for the next page until all pages are used.</li>
                <li>If a document runs out of pages, it will be skipped, and the tool will continue alternating with the remaining documents.</li>
            </ul>
        </div>
        <ul id="alternate-file-list" class="space-y-2"></ul>
        <button id="process-btn" class="btn-gradient w-full mt-6" disabled>Alternate & Mix PDFs</button>
    </div>
`,
};