// Schedule automated backups
function schedule_backup_tasks() {
    // Daily backup at 2 AM
    if (!wp_next_scheduled('daily_backup')) {
        wp_schedule_event(strtotime('02:00:00'), 'daily', 'daily_backup');
    }

    // Weekly backup on Sunday at 3 AM
    if (!wp_next_scheduled('weekly_backup')) {
        wp_schedule_event(strtotime('next Sunday 03:00:00'), 'weekly', 'weekly_backup');
    }

    // Monthly backup on first day at 4 AM
    if (!wp_next_scheduled('monthly_backup')) {
        wp_schedule_event(strtotime('first day of next month 04:00:00'), 'monthly', 'monthly_backup');
    }
}
add_action('wp', 'schedule_backup_tasks');

// Execute backup tasks
function execute_daily_backup() {
    perform_backup('daily');
}

function execute_weekly_backup() {
    perform_backup('weekly');
}

function execute_monthly_backup() {
    perform_backup('monthly');
}

add_action('daily_backup', 'execute_daily_backup');
add_action('weekly_backup', 'execute_weekly_backup');
add_action('monthly_backup', 'execute_monthly_backup');

// Generate secure download link
function generate_backup_download_link($backup_id, $expiration = 3600) {
    $download_token = wp_generate_password(32, false);
    $download_url = add_query_arg(array(
        'action' => 'download_backup',
        'backup_id' => $backup_id,
        'token' => $download_token,
        'expires' => time() + $expiration
    ), admin_url('admin-ajax.php'));

    // Store token temporarily
    set_transient('backup_download_' . $download_token, array(
        'backup_id' => $backup_id,
        'expires' => time() + $expiration
    ), $expiration);

    return $download_url;
}

// Handle download request
function handle_backup_download() {
    $backup_id = sanitize_text_field($_GET['backup_id']);
    $token = sanitize_text_field($_GET['token']);
    $expires = intval($_GET['expires']);

    // Validate token
    $token_data = get_transient('backup_download_' . $token);
    if (!$token_data || $token_data['backup_id'] !== $backup_id || time() > $expires) {
        wp_die('Invalid or expired download link');
    }

    // Delete token after use
    delete_transient('backup_download_' . $token);

    // Serve backup file
    $backup_path = get_backup_file_path($backup_id);
    if (file_exists($backup_path)) {
        header('Content-Type: application/octet-stream');
        header('Content-Disposition: attachment; filename="' . basename($backup_path) . '"');
        header('Content-Length: ' . filesize($backup_path));
        readfile($backup_path);
        exit;
    } else {
        wp_die('Backup file not found');
    }
}
add_action('wp_ajax_download_backup', 'handle_backup_download');
add_action('wp_ajax_nopriv_download_backup', 'handle_backup_download');

# Restore database from backup
mysql -h localhost -u username -p database_name < backup.sql

# Or using WP-CLI
wp db import backup.sql

# Update site URLs if domain changed
wp search-replace 'old-domain.com' 'new-domain.com'

# Restore WordPress files
tar -xzf wordpress-backup.tar.gz -C /path/to/wordpress

# Or using rsync for large sites
rsync -avz backup-files/ /path/to/wordpress/

# Fix file permissions
find /path/to/wordpress -type f -exec chmod 644 {} \;
find /path/to/wordpress -type d -exec chmod 755 {} \;

// Restore WordPress configuration
define('DB_NAME', 'restored_database');
define('DB_USER', 'restored_user');
define('DB_PASSWORD', 'restored_password');
define('DB_HOST', 'localhost');

// Restore permalinks
global $wp_rewrite;
$wp_rewrite->flush_rules();

// Encrypt backup files
function encrypt_backup_file($file_path, $encryption_key) {
    $file_contents = file_get_contents($file_path);
    $encrypted = openssl_encrypt($file_contents, 'AES-256-CBC', $encryption_key, 0, substr($encryption_key, 0, 16));
    file_put_contents($file_path . '.encrypted', $encrypted);
    unlink($file_path); // Remove unencrypted file
}

// Decrypt backup files
function decrypt_backup_file($encrypted_file_path, $encryption_key) {
    $encrypted_contents = file_get_contents($encrypted_file_path);
    $decrypted = openssl_decrypt($encrypted_contents, 'AES-256-CBC', $encryption_key, 0, substr($encryption_key, 0, 16));
    return $decrypted;
}

// Generate backup checksums
function generate_backup_checksum($backup_path) {
    $checksums = array();

    $iterator = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($backup_path));
    foreach ($iterator as $file) {
        if ($file->isFile()) {
            $relative_path = str_replace($backup_path . '/', '', $file->getPathname());
            $checksums[$relative_path] = hash_file('sha256', $file->getPathname());
        }
    }

    file_put_contents($backup_path . '/checksums.sha256', json_encode($checksums, JSON_PRETTY_PRINT));
    return $checksums;
}

// Verify backup integrity
function verify_backup_integrity($backup_path) {
    $checksums_file = $backup_path . '/checksums.sha256';

    if (!file_exists($checksums_file)) {
        return array('valid' => false, 'error' => 'Checksums file not found');
    }

    $stored_checksums = json_decode(file_get_contents($checksums_file), true);
    $current_checksums = generate_backup_checksum($backup_path);

    $differences = array();
    foreach ($stored_checksums as $file => $stored_hash) {
        if (!isset($current_checksums[$file])) {
            $differences[] = "Missing file: {$file}";
        } elseif ($current_checksums[$file] !== $stored_hash) {
            $differences[] = "Modified file: {$file}";
        }
    }

    return array(
        'valid' => empty($differences),
        'differences' => $differences
    );
}

// Backup failure notifications
function send_backup_failure_alert($backup_type, $error_message) {
    $admin_email = get_option('admin_email');
    $site_name = get_bloginfo('name');

    $subject = "Backup Failed - {$site_name}";
    $message = "
    <h3>Backup Failure Alert</h3>
    <p><strong>Backup Type:</strong> {$backup_type}</p>
    <p><strong>Error:</strong> {$error_message}</p>
    <p><strong>Time:</strong> " . current_time('mysql') . "</p>
    <p>Please check the backup system and resolve the issue.</p>
    ";

    wp_mail($admin_email, $subject, $message, array('Content-Type: text/html; charset=UTF-8'));
}

// Success notifications
function send_backup_success_alert($backup_type, $backup_size, $duration) {
    $admin_email = get_option('admin_email');
    $site_name = get_bloginfo('name');

    $subject = "Backup Completed - {$site_name}";
    $message = "
    <h3>Backup Success Alert</h3>
    <p><strong>Backup Type:</strong> {$backup_type}</p>
    <p><strong>Size:</strong> " . size_format($backup_size) . "</p>
    <p><strong>Duration:</strong> {$duration} seconds</p>
    <p><strong>Time:</strong> " . current_time('mysql') . "</p>
    ";

    wp_mail($admin_email, $subject, $message, array('Content-Type: text/html; charset=UTF-8'));
}

// Add backup status to dashboard
function add_backup_status_widget() {
    wp_add_dashboard_widget(
        'backup_status_widget',
        'Backup Status',
        'display_backup_status_widget'
    );
}

function display_backup_status_widget() {
    $last_backup = get_option('last_backup_time');
    $backup_status = get_option('backup_status');
    $storage_used = get_option('backup_storage_used');

    echo '<div class="backup-status-widget">';
    echo '<p><strong>Last Backup:</strong> ' . ($last_backup ? date('M j, Y H:i', $last_backup) : 'Never') . '</p>';
    echo '<p><strong>Status:</strong> <span class="' . ($backup_status === 'success' ? 'success' : 'error') . '">' . ucfirst($backup_status) . '</span></p>';
    echo '<p><strong>Storage Used:</strong> ' . ($storage_used ? size_format($storage_used) : 'Unknown') . '</p>';

    if ($backup_status !== 'success') {
        echo '<p><a href="' . admin_url('admin.php?page=backup-settings') . '" class="button">Fix Backup Issues</a></p>';
    }

    echo '</div>';
}
add_action('wp_dashboard_setup', 'add_backup_status_widget');