<?php
// index.php - All-in-one PDF Tools Website

// Configuration
$MAX_FILE_SIZE = 50 * 1024 * 1024; // 50MB
$UPLOAD_DIR = 'uploads/';
$FILE_LIFETIME = 3600; // 1 hour in seconds

// Check if requirements are met
function check_requirements() {
    $errors = [];
    
    // Check PHP version
    if (version_compare(PHP_VERSION, '7.4.0') < 0) {
        $errors[] = "PHP 7.4 or higher is required.";
    }
    
    // Check required extensions
    $required_extensions = ['gd', 'zip', 'mbstring', 'xml', 'fileinfo'];
    foreach ($required_extensions as $ext) {
        if (!extension_loaded($ext)) {
            $errors[] = "PHP extension '{$ext}' is not loaded.";
        }
    }
    
    // Check Ghostscript
    if (!shell_exec('which gs')) {
        $errors[] = "Ghostscript (gs) is not installed or not in PATH.";
    }
    
    // Check if upload directory is writable
    if (!is_writable('uploads/') && !mkdir('uploads/', 0755, true)) {
        $errors[] = "Upload directory is not writable.";
    }
    
    return $errors;
}

// Handle file upload with validation
function handle_upload($field_name, $allowed_types = ['application/pdf']) {
    global $MAX_FILE_SIZE, $UPLOAD_DIR;
    
    if (!isset($_FILES[$field_name])) {
        return ['error' => 'No file uploaded'];
    }
    
    $file = $_FILES[$field_name];
    
    // Check for upload errors
    if ($file['error'] !== UPLOAD_ERR_OK) {
        $upload_errors = [
            UPLOAD_ERR_INI_SIZE => 'File exceeds upload_max_filesize directive in php.ini',
            UPLOAD_ERR_FORM_SIZE => 'File exceeds MAX_FILE_SIZE directive in HTML form',
            UPLOAD_ERR_PARTIAL => 'File was only partially uploaded',
            UPLOAD_ERR_NO_FILE => 'No file was uploaded',
            UPLOAD_ERR_NO_TMP_DIR => 'Missing temporary folder',
            UPLOAD_ERR_CANT_WRITE => 'Failed to write file to disk',
            UPLOAD_ERR_EXTENSION => 'File upload stopped by PHP extension'
        ];
        return ['error' => $upload_errors[$file['error']] ?? 'Unknown upload error'];
    }
    
    // Check file size
    if ($file['size'] > $MAX_FILE_SIZE) {
        return ['error' => 'File is too large. Maximum size is ' . format_bytes($MAX_FILE_SIZE)];
    }
    
    // Check file type
    $finfo = new finfo(FILEINFO_MIME_TYPE);
    $mime = $finfo->file($file['tmp_name']);
    
    if (!in_array($mime, $allowed_types)) {
        return ['error' => 'Invalid file type. Only PDF files are allowed'];
    }
    
    // Generate unique filename
    if (!is_dir($UPLOAD_DIR)) {
        mkdir($UPLOAD_DIR, 0755, true);
    }
    
    $filename = uniqid() . '.pdf';
    $destination = $UPLOAD_DIR . $filename;
    
    if (!move_uploaded_file($file['tmp_name'], $destination)) {
        return ['error' => 'Failed to move uploaded file'];
    }
    
    return [
        'success' => true, 
        'filepath' => $destination, 
        'filename' => $filename,
        'original_name' => $file['name'],
        'size' => $file['size']
    ];
}

// Format bytes to human-readable format
function format_bytes($bytes, $precision = 2) {
    $units = ['B', 'KB', 'MB', 'GB', 'TB'];
    $bytes = max($bytes, 0);
    $pow = floor(($bytes ? log($bytes) : 0) / log(1024));
    $pow = min($pow, count($units) - 1);
    $bytes /= pow(1024, $pow);
    return round($bytes, $precision) . ' ' . $units[$pow];
}

// PDF Tools Functions
function merge_pdfs($files, $output_filename) {
    $cmd = "gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=" . escapeshellarg($output_filename) . " ";
    foreach ($files as $file) {
        $cmd .= escapeshellarg($file) . ' ';
    }
    
    exec($cmd, $output, $return_var);
    
    if ($return_var !== 0) {
        return ['error' => 'Failed to merge PDFs. Ghostscript error.'];
    }
    
    if (!file_exists($output_filename) || filesize($output_filename) === 0) {
        return ['error' => 'Merged PDF creation failed'];
    }
    
    return ['success' => true, 'filepath' => $output_filename];
}

function split_pdf($filepath, $output_dir, $pages) {
    $output_files = [];
    
    foreach ($pages as $i => $page_range) {
        $output_file = $output_dir . 'split_' . ($i + 1) . '.pdf';
        $cmd = "gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -dFirstPage={$page_range[0]} -dLastPage={$page_range[1]} -sOutputFile=" . escapeshellarg($output_file) . " " . escapeshellarg($filepath);
        
        exec($cmd, $output, $return_var);
        
        if ($return_var !== 0 || !file_exists($output_file)) {
            return ['error' => "Failed to split PDF at page range {$page_range[0]}-{$page_range[1]}"];
        }
        
        $output_files[] = $output_file;
    }
    
    return ['success' => true, 'files' => $output_files];
}

function pdf_to_images($filepath, $output_dir, $format = 'jpg', $dpi = 150) {
    $output_pattern = $output_dir . 'page_%d.' . $format;
    $device = $format === 'png' ? 'png16m' : 'jpeg';
    $cmd = "gs -q -dNOPAUSE -dBATCH -sDEVICE=$device -r$dpi -sOutputFile=" . escapeshellarg($output_pattern) . " " . escapeshellarg($filepath);
    
    exec($cmd, $output, $return_var);
    
    if ($return_var !== 0) {
        return ['error' => 'Failed to convert PDF to images'];
    }
    
    // Get list of generated images
    $images = glob($output_dir . 'page_*.' . $format);
    if (empty($images)) {
        return ['error' => 'No images were generated'];
    }
    
    sort($images);
    
    return ['success' => true, 'images' => $images];
}

function compress_pdf($filepath, $output_file, $quality = 'ebook') {
    // Quality levels: screen (72dpi), ebook (150dpi), printer (300dpi), prepress (high quality)
    $cmd = "gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/$quality -sOutputFile=" . escapeshellarg($output_file) . " " . escapeshellarg($filepath);
    
    exec($cmd, $output, $return_var);
    
    if ($return_var !== 0 || !file_exists($output_file)) {
        return ['error' => 'Failed to compress PDF'];
    }
    
    return ['success' => true, 'filepath' => $output_file];
}

function protect_pdf($filepath, $output_file, $password) {
    $cmd = "qpdf --encrypt " . escapeshellarg($password) . " " . escapeshellarg($password) . " 256 -- " . escapeshellarg($filepath) . " " . escapeshellarg($output_file);
    
    exec($cmd, $output, $return_var);
    
    if ($return_var !== 0 || !file_exists($output_file)) {
        return ['error' => 'Failed to password protect PDF'];
    }
    
    return ['success' => true, 'filepath' => $output_file];
}

function unlock_pdf($filepath, $output_file, $password) {
    $cmd = "qpdf --decrypt --password=" . escapeshellarg($password) . " " . escapeshellarg($filepath) . " " . escapeshellarg($output_file);
    
    exec($cmd, $output, $return_var);
    
    if ($return_var !== 0 || !file_exists($output_file)) {
        return ['error' => 'Failed to unlock PDF. Wrong password or corrupted file.'];
    }
    
    return ['success' => true, 'filepath' => $output_file];
}

function pdf_to_text($filepath, $output_file) {
    $cmd = "pdftotext " . escapeshellarg($filepath) . " " . escapeshellarg($output_file);
    
    exec($cmd, $output, $return_var);
    
    if ($return_var !== 0 || !file_exists($output_file) || filesize($output_file) === 0) {
        return ['error' => 'Failed to extract text from PDF'];
    }
    
    return ['success' => true, 'filepath' => $output_file];
}

function create_zip($files, $zip_filename) {
    $zip = new ZipArchive();
    
    if ($zip->open($zip_filename, ZipArchive::CREATE | ZipArchive::OVERWRITE) !== TRUE) {
        return ['error' => 'Failed to create zip file'];
    }
    
    foreach ($files as $file) {
        if (file_exists($file)) {
            $zip->addFile($file, basename($file));
        }
    }
    
    $zip->close();
    
    if (!file_exists($zip_filename)) {
        return ['error' => 'Zip file creation failed'];
    }
    
    return ['success' => true, 'filepath' => $zip_filename];
}

// Clean up old files
function cleanup_old_files() {
    global $UPLOAD_DIR, $FILE_LIFETIME;
    
    $files = glob($UPLOAD_DIR . '*');
    $now = time();
    
    foreach ($files as $file) {
        if (is_file($file) && ($now - filemtime($file) > $FILE_LIFETIME)) {
            if (is_dir($file)) {
                array_map('unlink', glob("$file/*"));
                rmdir($file);
            } else {
                unlink($file);
            }
        }
    }
}

// Main processing
session_start();
cleanup_old_files();

$errors = check_requirements();
$action = $_GET['action'] ?? '';
$result = null;
$download_link = '';
$original_filename = '';

// Process actions
if (empty($errors)) {
    switch ($action) {
        case 'merge':
            if ($_SERVER['REQUEST_METHOD'] === 'POST') {
                $files = [];
                $upload_errors = [];
                
                foreach ($_FILES['pdf_files']['tmp_name'] as $i => $tmp_name) {
                    if ($_FILES['pdf_files']['error'][$i] === UPLOAD_ERR_OK) {
                        $upload = handle_upload('pdf_files');
                        if (isset($upload['filepath'])) {
                            $files[] = $upload['filepath'];
                            if ($i === 0) $original_filename = pathinfo($upload['original_name'], PATHINFO_FILENAME);
                        } else {
                            $upload_errors[] = $upload['error'];
                        }
                    }
                }
                
                if (count($files) > 1) {
                    $output_file = $UPLOAD_DIR . 'merged_' . uniqid() . '.pdf';
                    $result = merge_pdfs($files, $output_file);
                    
                    if (isset($result['filepath'])) {
                        $download_link = $result['filepath'];
                        $original_filename = $original_filename ? $original_filename . '_merged' : 'merged';
                    }
                } else {
                    $result = ['error' => 'You need to upload at least 2 PDF files to merge'];
                }
                
                if (!empty($upload_errors)) {
                    $result['upload_errors'] = $upload_errors;
                }
            }
            break;
            
        case 'split':
            if ($_SERVER['REQUEST_METHOD'] === 'POST') {
                $upload = handle_upload('pdf_file');
                
                if (isset($upload['filepath'])) {
                    $original_filename = pathinfo($upload['original_name'], PATHINFO_FILENAME);
                    $page_ranges = [];
                    $ranges = explode(',', $_POST['page_ranges']);
                    
                    foreach ($ranges as $range) {
                        $parts = explode('-', trim($range));
                        if (count($parts) === 1) {
                            $page_ranges[] = [$parts[0], $parts[0]];
                        } else {
                            $page_ranges[] = [$parts[0], $parts[1] ?? $parts[0]];
                        }
                    }
                    
                    $output_dir = $UPLOAD_DIR . 'split_' . uniqid() . '/';
                    mkdir($output_dir, 0755, true);
                    
                    $result = split_pdf($upload['filepath'], $output_dir, $page_ranges);
                    
                    if (isset($result['files'])) {
                        $zip_filename = $UPLOAD_DIR . 'split_' . uniqid() . '.zip';
                        $zip_result = create_zip($result['files'], $zip_filename);
                        
                        if (isset($zip_result['filepath'])) {
                            $download_link = $zip_result['filepath'];
                            $original_filename = $original_filename ? $original_filename . '_split' : 'split';
                        } else {
                            $result = $zip_result;
                        }
                    }
                } else {
                    $result = $upload;
                }
            }
            break;
            
        case 'pdf_to_jpg':
            if ($_SERVER['REQUEST_METHOD'] === 'POST') {
                $upload = handle_upload('pdf_file');
                
                if (isset($upload['filepath'])) {
                    $original_filename = pathinfo($upload['original_name'], PATHINFO_FILENAME);
                    $output_dir = $UPLOAD_DIR . 'images_' . uniqid() . '/';
                    mkdir($output_dir, 0755, true);
                    
                    $format = $_POST['format'] ?? 'jpg';
                    $dpi = min(max(intval($_POST['dpi'] ?? 150), 300, 72);
                    
                    $result = pdf_to_images($upload['filepath'], $output_dir, $format, $dpi);
                    
                    if (isset($result['images'])) {
                        $zip_filename = $UPLOAD_DIR . 'images_' . uniqid() . '.zip';
                        $zip_result = create_zip($result['images'], $zip_filename);
                        
                        if (isset($zip_result['filepath'])) {
                            $download_link = $zip_result['filepath'];
                            $original_filename = $original_filename ? $original_filename . '_images' : 'images';
                        } else {
                            $result = $zip_result;
                        }
                    }
                } else {
                    $result = $upload;
                }
            }
            break;
            
        case 'compress':
            if ($_SERVER['REQUEST_METHOD'] === 'POST') {
                $upload = handle_upload('pdf_file');
                
                if (isset($upload['filepath'])) {
                    $original_filename = pathinfo($upload['original_name'], PATHINFO_FILENAME);
                    $quality = $_POST['quality'] ?? 'ebook';
                    $output_file = $UPLOAD_DIR . 'compressed_' . uniqid() . '.pdf';
                    
                    $result = compress_pdf($upload['filepath'], $output_file, $quality);
                    
                    if (isset($result['filepath'])) {
                        $download_link = $result['filepath'];
                        $original_filename = $original_filename ? $original_filename . '_compressed' : 'compressed';
                    }
                } else {
                    $result = $upload;
                }
            }
            break;
            
        case 'protect':
            if ($_SERVER['REQUEST_METHOD'] === 'POST') {
                $upload = handle_upload('pdf_file');
                
                if (isset($upload['filepath'])) {
                    $original_filename = pathinfo($upload['original_name'], PATHINFO_FILENAME);
                    $password = $_POST['password'] ?? '';
                    
                    if (empty($password)) {
                        $result = ['error' => 'Password is required'];
                    } else {
                        $output_file = $UPLOAD_DIR . 'protected_' . uniqid() . '.pdf';
                        $result = protect_pdf($upload['filepath'], $output_file, $password);
                        
                        if (isset($result['filepath'])) {
                            $download_link = $result['filepath'];
                            $original_filename = $original_filename ? $original_filename . '_protected' : 'protected';
                        }
                    }
                } else {
                    $result = $upload;
                }
            }
            break;
            
        case 'unlock':
            if ($_SERVER['REQUEST_METHOD'] === 'POST') {
                $upload = handle_upload('pdf_file');
                
                if (isset($upload['filepath'])) {
                    $original_filename = pathinfo($upload['original_name'], PATHINFO_FILENAME);
                    $password = $_POST['password'] ?? '';
                    
                    if (empty($password)) {
                        $result = ['error' => 'Password is required'];
                    } else {
                        $output_file = $UPLOAD_DIR . 'unlocked_' . uniqid() . '.pdf';
                        $result = unlock_pdf($upload['filepath'], $output_file, $password);
                        
                        if (isset($result['filepath'])) {
                            $download_link = $result['filepath'];
                            $original_filename = $original_filename ? $original_filename . '_unlocked' : 'unlocked';
                        }
                    }
                } else {
                    $result = $upload;
                }
            }
            break;
            
        case 'pdf_to_text':
            if ($_SERVER['REQUEST_METHOD'] === 'POST') {
                $upload = handle_upload('pdf_file');
                
                if (isset($upload['filepath'])) {
                    $original_filename = pathinfo($upload['original_name'], PATHINFO_FILENAME);
                    $output_file = $UPLOAD_DIR . 'text_' . uniqid() . '.txt';
                    
                    $result = pdf_to_text($upload['filepath'], $output_file);
                    
                    if (isset($result['filepath'])) {
                        $download_link = $result['filepath'];
                        $original_filename = $original_filename ? $original_filename . '_text' : 'text';
                    }
                } else {
                    $result = $upload;
                }
            }
            break;
    }
}

// HTML Interface
?>
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>PDF Tools - All-in-One PDF Solution</title>
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.0.0-beta3/css/all.min.css">
    <style>
        :root {
            --primary-color: #ff4b4b;
            --primary-dark: #e04343;
            --secondary-color: #4b6cff;
            --dark-color: #333;
            --light-color: #f8f9fa;
            --gray-color: #6c757d;
            --light-gray: #e9ecef;
            --success-color: #28a745;
            --warning-color: #ffc107;
            --danger-color: #dc3545;
            --border-radius: 8px;
            --box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
            --transition: all 0.3s ease;
        }
        
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        
        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            line-height: 1.6;
            color: var(--dark-color);
            background-color: var(--light-color);
        }
        
        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
        }
        
        header {
            background-color: var(--primary-color);
            color: white;
            padding: 20px 0;
            box-shadow: var(--box-shadow);
            position: sticky;
            top: 0;
            z-index: 100;
        }
        
        .header-content {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        
        .logo {
            font-size: 1.8rem;
            font-weight: bold;
            display: flex;
            align-items: center;
        }
        
        .logo i {
            margin-right: 10px;
        }
        
        nav ul {
            display: flex;
            list-style: none;
        }
        
        nav ul li {
            margin-left: 20px;
        }
        
        nav ul li a {
            color: white;
            text-decoration: none;
            font-weight: 500;
            transition: var(--transition);
        }
        
        nav ul li a:hover {
            opacity: 0.9;
        }
        
        .hero {
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            color: white;
            padding: 60px 0;
            text-align: center;
        }
        
        .hero h1 {
            font-size: 2.5rem;
            margin-bottom: 20px;
        }
        
        .hero p {
            font-size: 1.2rem;
            max-width: 800px;
            margin: 0 auto 30px;
        }
        
        .btn {
            display: inline-block;
            background-color: white;
            color: var(--primary-color);
            padding: 12px 30px;
            border-radius: var(--border-radius);
            text-decoration: none;
            font-weight: bold;
            transition: var(--transition);
            border: none;
            cursor: pointer;
            font-size: 1rem;
        }
        
        .btn:hover {
            transform: translateY(-3px);
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
        }
        
        .btn-primary {
            background-color: var(--primary-color);
            color: white;
        }
        
        .btn-primary:hover {
            background-color: var(--primary-dark);
        }
        
        .tools-section {
            padding: 60px 0;
        }
        
        .section-title {
            text-align: center;
            margin-bottom: 40px;
        }
        
        .section-title h2 {
            font-size: 2rem;
            color: var(--dark-color);
            margin-bottom: 15px;
        }
        
        .section-title p {
            color: var(--gray-color);
            max-width: 700px;
            margin: 0 auto;
        }
        
        .tools-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
            gap: 25px;
        }
        
        .tool-card {
            background: white;
            border-radius: var(--border-radius);
            padding: 25px;
            box-shadow: var(--box-shadow);
            transition: var(--transition);
            text-align: center;
        }
        
        .tool-card:hover {
            transform: translateY(-10px);
        }
        
        .tool-icon {
            font-size: 2.5rem;
            color: var(--primary-color);
            margin-bottom: 20px;
        }
        
        .tool-card h3 {
            margin-bottom: 15px;
            font-size: 1.3rem;
        }
        
        .tool-card p {
            color: var(--gray-color);
            margin-bottom: 20px;
        }
        
        .form-container {
            background: white;
            border-radius: var(--border-radius);
            padding: 30px;
            box-shadow: var(--box-shadow);
            max-width: 800px;
            margin: 40px auto;
        }
        
        .form-title {
            text-align: center;
            margin-bottom: 30px;
        }
        
        .form-title h2 {
            font-size: 1.8rem;
            color: var(--dark-color);
            margin-bottom: 10px;
        }
        
        .form-title p {
            color: var(--gray-color);
        }
        
        .form-group {
            margin-bottom: 20px;
        }
        
        .form-group label {
            display: block;
            margin-bottom: 8px;
            font-weight: 500;
        }
        
        .form-control {
            width: 100%;
            padding: 12px 15px;
            border: 1px solid var(--light-gray);
            border-radius: var(--border-radius);
            font-size: 1rem;
            transition: var(--transition);
        }
        
        .form-control:focus {
            outline: none;
            border-color: var(--primary-color);
            box-shadow: 0 0 0 3px rgba(255, 75, 75, 0.2);
        }
        
        .file-drop-area {
            border: 2px dashed var(--light-gray);
            border-radius: var(--border-radius);
            padding: 30px;
            text-align: center;
            transition: var(--transition);
            margin-bottom: 20px;
        }
        
        .file-drop-area:hover {
            border-color: var(--primary-color);
        }
        
        .file-drop-area.active {
            border-color: var(--primary-color);
            background-color: rgba(255, 75, 75, 0.05);
        }
        
        .file-msg {
            font-size: 1rem;
            color: var(--gray-color);
            margin-bottom: 15px;
        }
        
        .file-input {
            display: none;
        }
        
        .file-label {
            background-color: var(--primary-color);
            color: white;
            padding: 10px 20px;
            border-radius: var(--border-radius);
            cursor: pointer;
            transition: var(--transition);
            display: inline-block;
        }
        
        .file-label:hover {
            background-color: var(--primary-dark);
        }
        
        .file-list {
            margin-top: 15px;
        }
        
        .file-item {
            display: flex;
            align-items: center;
            padding: 10px;
            background-color: var(--light-gray);
            border-radius: var(--border-radius);
            margin-bottom: 10px;
        }
        
        .file-item i {
            margin-right: 10px;
            color: var(--primary-color);
        }
        
        .file-info {
            flex: 1;
            text-align: left;
        }
        
        .file-name {
            font-weight: 500;
            margin-bottom: 5px;
        }
        
        .file-size {
            font-size: 0.8rem;
            color: var(--gray-color);
        }
        
        .remove-file {
            color: var(--danger-color);
            cursor: pointer;
            margin-left: 10px;
        }
        
        .alert {
            padding: 15px;
            border-radius: var(--border-radius);
            margin-bottom: 20px;
        }
        
        .alert-danger {
            background-color: rgba(220, 53, 69, 0.1);
            color: var(--danger-color);
            border: 1px solid rgba(220, 53, 69, 0.2);
        }
        
        .alert-success {
            background-color: rgba(40, 167, 69, 0.1);
            color: var(--success-color);
            border: 1px solid rgba(40, 167, 69, 0.2);
        }
        
        .result-container {
            text-align: center;
            padding: 30px;
        }
        
        .result-icon {
            font-size: 4rem;
            color: var(--success-color);
            margin-bottom: 20px;
        }
        
        .download-btn {
            margin-top: 20px;
            font-size: 1.1rem;
            padding: 15px 40px;
        }
        
        .back-btn {
            display: inline-block;
            margin-top: 20px;
            color: var(--primary-color);
            text-decoration: none;
            font-weight: 500;
        }
        
        .back-btn i {
            margin-right: 5px;
        }
        
        .features-section {
            padding: 60px 0;
            background-color: white;
        }
        
        .features-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
            gap: 30px;
        }
        
        .feature-card {
            text-align: center;
            padding: 30px;
        }
        
        .feature-icon {
            font-size: 2.5rem;
            color: var(--primary-color);
            margin-bottom: 20px;
        }
        
        .feature-card h3 {
            margin-bottom: 15px;
        }
        
        .feature-card p {
            color: var(--gray-color);
        }
        
        footer {
            background-color: var(--dark-color);
            color: white;
            padding: 40px 0;
            text-align: center;
        }
        
        .footer-content {
            display: flex;
            flex-direction: column;
            align-items: center;
        }
        
        .footer-logo {
            font-size: 1.5rem;
            font-weight: bold;
            margin-bottom: 20px;
        }
        
        .footer-links {
            display: flex;
            list-style: none;
            margin-bottom: 20px;
        }
        
        .footer-links li {
            margin: 0 15px;
        }
        
        .footer-links a {
            color: white;
            text-decoration: none;
            transition: var(--transition);
        }
        
        .footer-links a:hover {
            color: var(--primary-color);
        }
        
        .social-links {
            margin-bottom: 20px;
        }
        
        .social-links a {
            color: white;
            font-size: 1.2rem;
            margin: 0 10px;
            transition: var(--transition);
        }
        
        .social-links a:hover {
            color: var(--primary-color);
        }
        
        .copyright {
            color: var(--light-gray);
            font-size: 0.9rem;
        }
        
        /* Responsive styles */
        @media (max-width: 768px) {
            .header-content {
                flex-direction: column;
            }
            
            nav ul {
                margin-top: 20px;
            }
            
            nav ul li {
                margin: 0 10px;
            }
            
            .hero h1 {
                font-size: 2rem;
            }
            
            .hero p {
                font-size: 1rem;
            }
            
            .form-container {
                padding: 20px;
            }
        }
        
        @media (max-width: 480px) {
            .tools-grid {
                grid-template-columns: 1fr;
            }
            
            .footer-links {
                flex-direction: column;
            }
            
            .footer-links li {
                margin: 5px 0;
            }
        }
    </style>
</head>
<body>
    <header>
        <div class="container header-content">
            <div class="logo">
                <i class="fas fa-file-pdf"></i>
                PDF Tools
            </div>
            <nav>
                <ul>
                    <li><a href="#features">Features</a></li>
                    <li><a href="#tools">Tools</a></li>
                    <li><a href="mailto:support@pdftools.com">Contact</a></li>
                </ul>
            </nav>
        </div>
    </header>
    
    <section class="hero">
        <div class="container">
            <h1>All Your PDF Needs in One Place</h1>
            <p>Merge, split, compress, convert and more - 100% free and easy to use. No installation or registration required.</p>
            <a href="#tools" class="btn btn-primary">Get Started</a>
        </div>
    </section>
    
    <?php if (!empty($errors)): ?>
        <div class="container">
            <div class="alert alert-danger">
                <h3>Server Requirements Not Met</h3>
                <ul>
                    <?php foreach ($errors as $error): ?>
                        <li><?= htmlspecialchars($error) ?></li>
                    <?php endforeach; ?>
                </ul>
                <p>Please contact your hosting provider to resolve these issues.</p>
            </div>
        </div>
    <?php endif; ?>
    
    <section id="tools" class="tools-section">
        <div class="container">
            <?php if ($action === ''): ?>
                <div class="section-title">
                    <h2>Popular PDF Tools</h2>
                    <p>Select the tool you need to work with your PDF files</p>
                </div>
                
                <div class="tools-grid">
                    <div class="tool-card">
                        <div class="tool-icon">
                            <i class="fas fa-object-group"></i>
                        </div>
                        <h3>Merge PDF</h3>
                        <p>Combine multiple PDF files into a single document in seconds.</p>
                        <a href="?action=merge" class="btn btn-primary">Merge PDFs</a>
                    </div>
                    
                    <div class="tool-card">
                        <div class="tool-icon">
                            <i class="fas fa-cut"></i>
                        </div>
                        <h3>Split PDF</h3>
                        <p>Extract pages or split a PDF into multiple files.</p>
                        <a href="?action=split" class="btn btn-primary">Split PDF</a>
                    </div>
                    
                    <div class="tool-card">
                        <div class="tool-icon">
                            <i class="fas fa-image"></i>
                        </div>
                        <h3>PDF to JPG</h3>
                        <p>Convert each page of your PDF to a JPG image.</p>
                        <a href="?action=pdf_to_jpg" class="btn btn-primary">Convert to JPG</a>
                    </div>
                    
                    <div class="tool-card">
                        <div class="tool-icon">
                            <i class="fas fa-compress-alt"></i>
                        </div>
                        <h3>Compress PDF</h3>
                        <p>Reduce the file size of your PDF documents.</p>
                        <a href="?action=compress" class="btn btn-primary">Compress PDF</a>
                    </div>
                    
                    <div class="tool-card">
                        <div class="tool-icon">
                            <i class="fas fa-lock"></i>
                        </div>
                        <h3>Protect PDF</h3>
                        <p>Add password protection to your PDF files.</p>
                        <a href="?action=protect" class="btn btn-primary">Protect PDF</a>
                    </div>
                    
                    <div class="tool-card">
                        <div class="tool-icon">
                            <i class="fas fa-unlock"></i>
                        </div>
                        <h3>Unlock PDF</h3>
                        <p>Remove password protection from PDF files.</p>
                        <a href="?action=unlock" class="btn btn-primary">Unlock PDF</a>
                    </div>
                    
                    <div class="tool-card">
                        <div class="tool-icon">
                            <i class="fas fa-file-alt"></i>
                        </div>
                        <h3>PDF to Text</h3>
                        <p>Extract text from your PDF documents.</p>
                        <a href="?action=pdf_to_text" class="btn btn-primary">Extract Text</a>
                    </div>
                </div>
            <?php else: ?>
                <a href="?" class="back-btn"><i class="fas fa-arrow-left"></i> Back to Tools</a>
                
                <div class="form-container">
                    <?php if (isset($result['error'])): ?>
                        <div class="alert alert-danger">
                            <i class="fas fa-exclamation-circle"></i> <?= htmlspecialchars($result['error']) ?>
                        </div>
                    <?php endif; ?>
                    
                    <?php if ($download_link): ?>
                        <div class="result-container">
                            <div class="result-icon">
                                <i class="fas fa-check-circle"></i>
                            </div>
                            <h2>Operation Completed Successfully!</h2>
                            <p>Your file is ready to download.</p>
                            <a href="<?= htmlspecialchars($download_link) ?>" class="btn btn-primary download-btn" download="
                                <?= htmlspecialchars($original_filename . '.' . pathinfo($download_link, PATHINFO_EXTENSION)) ?>">
                                <i class="fas fa-download"></i> Download File
                            </a>
                        </div>
                    <?php else: ?>
                        <?php if ($action === 'merge'): ?>
                            <div class="form-title">
                                <h2>Merge PDF Files</h2>
                                <p>Select multiple PDF files to merge them into a single document.</p>
                            </div>
                            
                            <?php if (isset($result['upload_errors'])): ?>
                                <div class="alert alert-danger">
                                    <h3>Upload Errors:</h3>
                                    <ul>
                                        <?php foreach ($result['upload_errors'] as $error): ?>
                                            <li><?= htmlspecialchars($error) ?></li>
                                        <?php endforeach; ?>
                                    </ul>
                                </div>
                            <?php endif; ?>
                            
                            <form method="post" enctype="multipart/form-data" id="merge-form">
                                <div class="form-group">
                                    <div class="file-drop-area" id="file-drop-area">
                                        <div class="file-msg">
                                            <i class="fas fa-cloud-upload-alt" style="font-size: 2rem; margin-bottom: 10px;"></i>
                                            <p>Drag & drop your PDF files here or click to browse</p>
                                            <p class="small">(Maximum file size: <?= format_bytes($MAX_FILE_SIZE) ?>)</p>
                                        </div>
                                        <input type="file" class="file-input" name="pdf_files[]" multiple accept=".pdf" required>
                                        <label for="file-input" class="file-label">Select Files</label>
                                    </div>
                                    <div class="file-list" id="file-list"></div>
                                </div>
                                <button type="submit" class="btn btn-primary">Merge PDFs</button>
                            </form>
                            
                            <script>
                                const fileDropArea = document.getElementById('file-drop-area');
                                const fileInput = document.querySelector('.file-input');
                                const fileList = document.getElementById('file-list');
                                
                                // Highlight drop area when file is dragged over
                                ['dragenter', 'dragover'].forEach(eventName => {
                                    fileDropArea.addEventListener(eventName, (e) => {
                                        e.preventDefault();
                                        fileDropArea.classList.add('active');
                                    });
                                });
                                
                                // Remove highlight when file leaves
                                ['dragleave', 'drop'].forEach(eventName => {
                                    fileDropArea.addEventListener(eventName, (e) => {
                                        e.preventDefault();
                                        fileDropArea.classList.remove('active');
                                    });
                                });
                                
                                // Handle dropped files
                                fileDropArea.addEventListener('drop', (e) => {
                                    e.preventDefault();
                                    fileInput.files = e.dataTransfer.files;
                                    updateFileList();
                                });
                                
                                // Handle selected files
                                fileInput.addEventListener('change', () => {
                                    updateFileList();
                                });
                                
                                // Update the file list display
                                function updateFileList() {
                                    fileList.innerHTML = '';
                                    
                                    if (fileInput.files.length > 0) {
                                        for (let i = 0; i < fileInput.files.length; i++) {
                                            const file = fileInput.files[i];
                                            const fileItem = document.createElement('div');
                                            fileItem.className = 'file-item';
                                            
                                            fileItem.innerHTML = `
                                                <i class="fas fa-file-pdf"></i>
                                                <div class="file-info">
                                                    <div class="file-name">${file.name}</div>
                                                    <div class="file-size">${formatBytes(file.size)}</div>
                                                </div>
                                                <span class="remove-file" data-index="${i}">&times;</span>
                                            `;
                                            
                                            fileList.appendChild(fileItem);
                                        }
                                        
                                        // Add event listeners to remove buttons
                                        document.querySelectorAll('.remove-file').forEach(button => {
                                            button.addEventListener('click', (e) => {
                                                const index = e.target.getAttribute('data-index');
                                                removeFile(index);
                                            });
                                        });
                                    }
                                }
                                
                                // Remove a file from the list
                                function removeFile(index) {
                                    const dt = new DataTransfer();
                                    const files = Array.from(fileInput.files);
                                    
                                    files.splice(index, 1);
                                    
                                    files.forEach(file => {
                                        dt.items.add(file);
                                    });
                                    
                                    fileInput.files = dt.files;
                                    updateFileList();
                                }
                                
                                // Format bytes to human-readable format
                                function formatBytes(bytes) {
                                    if (bytes === 0) return '0 Bytes';
                                    
                                    const k = 1024;
                                    const sizes = ['Bytes', 'KB', 'MB', 'GB'];
                                    const i = Math.floor(Math.log(bytes) / Math.log(k));
                                    
                                    return parseFloat((bytes / Math.pow(k, i)).toFixed(2) + ' ' + sizes[i];
                                }
                            </script>
                            
                        <?php elseif ($action === 'split'): ?>
                            <div class="form-title">
                                <h2>Split PDF File</h2>
                                <p>Upload a PDF file and specify page ranges to split (e.g., "1-3,5,7-9").</p>
                            </div>
                            
                            <form method="post" enctype="multipart/form-data">
                                <div class="form-group">
                                    <label for="pdf_file">PDF File:</label>
                                    <div class="file-drop-area">
                                        <div class="file-msg">
                                            <i class="fas fa-cloud-upload-alt" style="font-size: 2rem; margin-bottom: 10px;"></i>
                                            <p>Drag & drop your PDF file here or click to browse</p>
                                            <p class="small">(Maximum file size: <?= format_bytes($MAX_FILE_SIZE) ?>)</p>
                                        </div>
                                        <input type="file" class="file-input" name="pdf_file" id="pdf_file" accept=".pdf" required>
                                        <label for="pdf_file" class="file-label">Select File</label>
                                    </div>
                                </div>
                                <div class="form-group">
                                    <label for="page_ranges">Page Ranges:</label>
                                    <input type="text" class="form-control" name="page_ranges" id="page_ranges" 
                                           placeholder="e.g., 1-3,5,7-9" required>
                                    <small class="text-muted">Enter page ranges separated by commas (e.g., 1-3,5,7-9)</small>
                                </div>
                                <button type="submit" class="btn btn-primary">Split PDF</button>
                            </form>
                            
                        <?php elseif ($action === 'pdf_to_jpg'): ?>
                            <div class="form-title">
                                <h2>Convert PDF to Images</h2>
                                <p>Convert each page of your PDF to JPG or PNG images.</p>
                            </div>
                            
                            <form method="post" enctype="multipart/form-data">
                                <div class="form-group">
                                    <label for="pdf_file">PDF File:</label>
                                    <div class="file-drop-area">
                                        <div class="file-msg">
                                            <i class="fas fa-cloud-upload-alt" style="font-size: 2rem; margin-bottom: 10px;"></i>
                                            <p>Drag & drop your PDF file here or click to browse</p>
                                            <p class="small">(Maximum file size: <?= format_bytes($MAX_FILE_SIZE) ?>)</p>
                                        </div>
                                        <input type="file" class="file-input" name="pdf_file" id="pdf_file" accept=".pdf" required>
                                        <label for="pdf_file" class="file-label">Select File</label>
                                    </div>
                                </div>
                                <div class="form-group">
                                    <label for="format">Output Format:</label>
                                    <select class="form-control" name="format" id="format">
                                        <option value="jpg">JPG (Recommended)</option>
                                        <option value="png">PNG (Higher quality)</option>
                                    </select>
                                </div>
                                <div class="form-group">
                                    <label for="dpi">Image Quality (DPI):</label>
                                    <select class="form-control" name="dpi" id="dpi">
                                        <option value="72">Low (72 DPI)</option>
                                        <option value="150" selected>Medium (150 DPI)</option>
                                        <option value="300">High (300 DPI)</option>
                                    </select>
                                </div>
                                <button type="submit" class="btn btn-primary">Convert to Images</button>
                            </form>
                            
                        <?php elseif ($action === 'compress'): ?>
                            <div class="form-title">
                                <h2>Compress PDF</h2>
                                <p>Reduce the file size of your PDF document.</p>
                            </div>
                            
                            <form method="post" enctype="multipart/form-data">
                                <div class="form-group">
                                    <label for="pdf_file">PDF File:</label>
                                    <div class="file-drop-area">
                                        <div class="file-msg">
                                            <i class="fas fa-cloud-upload-alt" style="font-size: 2rem; margin-bottom: 10px;"></i>
                                            <p>Drag & drop your PDF file here or click to browse</p>
                                            <p class="small">(Maximum file size: <?= format_bytes($MAX_FILE_SIZE) ?>)</p>
                                        </div>
                                        <input type="file" class="file-input" name="pdf_file" id="pdf_file" accept=".pdf" required>
                                        <label for="pdf_file" class="file-label">Select File</label>
                                    </div>
                                </div>
                                <div class="form-group">
                                    <label for="quality">Compression Level:</label>
                                    <select class="form-control" name="quality" id="quality">
                                        <option value="screen">Low quality (smallest size)</option>
                                        <option value="ebook" selected>Medium quality</option>
                                        <option value="printer">High quality</option>
                                        <option value="prepress">Very high quality (largest size)</option>
                                    </select>
                                </div>
                                <button type="submit" class="btn btn-primary">Compress PDF</button>
                            </form>
                            
                        <?php elseif ($action === 'protect'): ?>
                            <div class="form-title">
                                <h2>Protect PDF</h2>
                                <p>Add password protection to your PDF file.</p>
                            </div>
                            
                            <form method="post" enctype="multipart/form-data">
                                <div class="form-group">
                                    <label for="pdf_file">PDF File:</label>
                                    <div class="file-drop-area">
                                        <div class="file-msg">
                                            <i class="fas fa-cloud-upload-alt" style="font-size: 2rem; margin-bottom: 10px;"></i>
                                            <p>Drag & drop your PDF file here or click to browse</p>
                                            <p class="small">(Maximum file size: <?= format_bytes($MAX_FILE_SIZE) ?>)</p>
                                        </div>
                                        <input type="file" class="file-input" name="pdf_file" id="pdf_file" accept=".pdf" required>
                                        <label for="pdf_file" class="file-label">Select File</label>
                                    </div>
                                </div>
                                <div class="form-group">
                                    <label for="password">Password:</label>
                                    <input type="password" class="form-control" name="password" id="password" required>
                                    <small class="text-muted">Remember this password. You'll need it to open the PDF.</small>
                                </div>
                                <button type="submit" class="btn btn-primary">Protect PDF</button>
                            </form>
                            
                        <?php elseif ($action === 'unlock'): ?>
                            <div class="form-title">
                                <h2>Unlock PDF</h2>
                                <p>Remove password protection from a PDF file.</p>
                            </div>
                            
                            <form method="post" enctype="multipart/form-data">
                                <div class="form-group">
                                    <label for="pdf_file">PDF File:</label>
                                    <div class="file-drop-area">
                                        <div class="file-msg">
                                            <i class="fas fa-cloud-upload-alt" style="font-size: 2rem; margin-bottom: 10px;"></i>
                                            <p>Drag & drop your PDF file here or click to browse</p>
                                            <p class="small">(Maximum file size: <?= format_bytes($MAX_FILE_SIZE) ?>)</p>
                                        </div>
                                        <input type="file" class="file-input" name="pdf_file" id="pdf_file" accept=".pdf" required>
                                        <label for="pdf_file" class="file-label">Select File</label>
                                    </div>
                                </div>
                                <div class="form-group">
                                    <label for="password">Password:</label>
                                    <input type="password" class="form-control" name="password" id="password" required>
                                    <small class="text-muted">Enter the password for the PDF file.</small>
                                </div>
                                <button type="submit" class="btn btn-primary">Unlock PDF</button>
                            </form>
                            
                        <?php elseif ($action === 'pdf_to_text'): ?>
                            <div class="form-title">
                                <h2>PDF to Text</h2>
                                <p>Extract text from your PDF document.</p>
                            </div>
                            
                            <form method="post" enctype="multipart/form-data">
                                <div class="form-group">
                                    <label for="pdf_file">PDF File:</label>
                                    <div class="file-drop-area">
                                        <div class="file-msg">
                                            <i class="fas fa-cloud-upload-alt" style="font-size: 2rem; margin-bottom: 10px;"></i>
                                            <p>Drag & drop your PDF file here or click to browse</p>
                                            <p class="small">(Maximum file size: <?= format_bytes($MAX_FILE_SIZE) ?>)</p>
                                        </div>
                                        <input type="file" class="file-input" name="pdf_file" id="pdf_file" accept=".pdf" required>
                                        <label for="pdf_file" class="file-label">Select File</label>
                                    </div>
                                </div>
                                <button type="submit" class="btn btn-primary">Extract Text</button>
                            </form>
                        <?php endif; ?>
                    <?php endif; ?>
                </div>
            <?php endif; ?>
        </div>
    </section>
    
    <section id="features" class="features-section">
        <div class="container">
            <div class="section-title">
                <h2>Why Choose Our PDF Tools?</h2>
                <p>We provide the best PDF tools with these amazing features</p>
            </div>
            
            <div class="features-grid">
                <div class="feature-card">
                    <div class="feature-icon">
                        <i class="fas fa-shield-alt"></i>
                    </div>
                    <h3>Secure Processing</h3>
                    <p>Your files are processed securely and deleted automatically after 1 hour. We don't store your documents permanently.</p>
                </div>
                
                <div class="feature-card">
                    <div class="feature-icon">
                        <i class="fas fa-bolt"></i>
                    </div>
                    <h3>Fast Processing</h3>
                    <p>Our tools use optimized algorithms to process your PDF files as quickly as possible, saving you time.</p>
                </div>
                
                <div class="feature-card">
                    <div class="feature-icon">
                        <i class="fas fa-desktop"></i>
                    </div>
                    <h3>No Installation</h3>
                    <p>All tools work directly in your browser. No software installation or registration required.</p>
                </div>
                
                <div class="feature-card">
                    <div class="feature-icon">
                        <i class="fas fa-heart"></i>
                    </div>
                    <h3>100% Free</h3>
                    <p>All our PDF tools are completely free to use with no hidden charges or limitations.</p>
                </div>
                
                <div class="feature-card">
                    <div class="feature-icon">
                        <i class="fas fa-mobile-alt"></i>
                    </div>
                    <h3>Mobile Friendly</h3>
                    <p>Works perfectly on all devices including smartphones and tablets.</p>
                </div>
                
                <div class="feature-card">
                    <div class="feature-icon">
                        <i class="fas fa-infinity"></i>
                    </div>
                    <h3>Unlimited Usage</h3>
                    <p>Use our tools as many times as you need without any restrictions.</p>
                </div>
            </div>
        </div>
    </section>
    
    <footer>
        <div class="container footer-content">
            <div class="footer-logo">
                <i class="fas fa-file-pdf"></i> PDF Tools
            </div>
            <ul class="footer-links">
                <li><a href="?">Home</a></li>
                <li><a href="#features">Features</a></li>
                <li><a href="#tools">Tools</a></li>
                <li><a href="mailto:support@pdftools.com">Contact</a></li>
                <li><a href="#">Privacy Policy</a></li>
            </ul>
            <div class="social-links">
                <a href="#"><i class="fab fa-facebook"></i></a>
                <a href="#"><i class="fab fa-twitter"></i></a>
                <a href="#"><i class="fab fa-instagram"></i></a>
                <a href="#"><i class="fab fa-github"></i></a>
            </div>
            <p class="copyright">© <?= date('Y') ?> PDF Tools. All rights reserved.</p>
        </div>
    </footer>
</body>
</html>