<?php
ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

// Set the working directory to the project root
chdir(__DIR__ . '/..');

require_once 'include/init.php';
require_once 'include/auth.php';

// Check if the user is logged in
if (!isset($_SESSION['user_id'])) {
    header('Location: /login.php');
    exit;
}

/**
 * Recursively removes a directory and its contents.
 * @param string $dir The directory to remove.
 */
function rrmdir($dir) {
    if (is_dir($dir)) {
        $objects = scandir($dir);
        foreach ($objects as $object) {
            if ($object != "." && $object != "..") {
                if (is_dir($dir . DIRECTORY_SEPARATOR . $object) && !is_link($dir . DIRECTORY_SEPARATOR . $object)) {
                    rrmdir($dir . DIRECTORY_SEPARATOR . $object);
                } else {
                    @unlink($dir . DIRECTORY_SEPARATOR . $object);
                }
            }
        }
        @rmdir($dir);
    }
}

/**
 * Creates a zip archive from a source directory.
 * @param string $source The source directory.
 * @param string $destination The path for the destination zip file.
 * @param string &$error_message Reference to a variable to store error messages.
 * @return bool True on success, false on failure.
 */
function createZipArchive($source, $destination, &$error_message) {
    if (!extension_loaded('zip')) {
        $error_message = 'The "zip" PHP extension is not installed or enabled.';
        return false;
    }
    if (!file_exists($source)) {
        $error_message = "Source path does not exist: " . $source;
        return false;
    }

    $zip = new ZipArchive();
    if ($zip->open($destination, ZipArchive::CREATE | ZipArchive::OVERWRITE) !== TRUE) {
        $error_message = 'Failed to create zip archive. Check server permissions and logs.';
        return false;
    }

    $source = realpath($source);

    if (is_dir($source)) {
        $files = new RecursiveIteratorIterator(
            new RecursiveDirectoryIterator($source, RecursiveDirectoryIterator::SKIP_DOTS),
            RecursiveIteratorIterator::SELF_FIRST
        );

        foreach ($files as $file) {
            $file = realpath($file);
            $relativePath = str_replace($source . DIRECTORY_SEPARATOR, '', $file);
            
            if (is_dir($file)) {
                $zip->addEmptyDir($relativePath);
            } else if (is_file($file)) {
                $zip->addFromString($relativePath, file_get_contents($file));
            }
        }
    }

    if (!$zip->close()) {
        $error_message = "Failed to write and close the zip archive. Check for disk space and permissions.";
        return false;
    }
    
    return true;
}

$projectRoot = realpath(__DIR__ . '/..');

// --- Main Logic ---
$tab_id = $_GET['tab_id'] ?? 'full';
$error_message = '';

if ($tab_id === 'full') {
    // --- Full Backup Logic ---
    $dataDir = 'data';
    $backupFileName = 'bookmarkly_full_backup_' . date('Y-m-d_H-i-s') . '.zip';
    $backupFilePath = sys_get_temp_dir() . DIRECTORY_SEPARATOR . $backupFileName;
    
    if (createZipArchive($dataDir, $backupFilePath, $error_message)) {
        header('Content-Type: application/zip');
        header('Content-Disposition: attachment; filename="' . $backupFileName . '"');
        header('Content-Length: ' . filesize($backupFilePath));
        readfile($backupFilePath);
        unlink($backupFilePath);
        exit;
    } else {
        $_SESSION['flash_message'] = ['text' => 'Failed to create full backup. Reason: ' . $error_message, 'type' => 'danger'];
        header('Location: ../settings.php');
        exit;
    }
} else {
    // --- Tab-specific Backup Logic ---
    $tab_id = filter_var($tab_id, FILTER_VALIDATE_INT);
    if ($tab_id === false) {
        $_SESSION['flash_message'] = ['text' => 'Invalid Tab ID.', 'type' => 'danger'];
        header('Location: ../settings.php');
        exit;
    }

    $temp_dir = sys_get_temp_dir() . '/bookmarkly_tab_backup_' . uniqid();
    if (!mkdir($temp_dir, 0777, true)) {
        $_SESSION['flash_message'] = ['text' => 'Failed to create temporary directory for backup.', 'type' => 'danger'];
        header('Location: ../settings.php');
        exit;
    }
    
    try {
        // --- START DEBUGGING ---
        $log_path = sys_get_temp_dir() . DIRECTORY_SEPARATOR . 'bookmarkly_backup_debug.log';
        $log_file = fopen($log_path, 'w');
        if ($log_file) {
            fwrite($log_file, "--- Starting Tab Backup Debug ---\n");
            fwrite($log_file, "Log file location: " . $log_path . "\n");
            fwrite($log_file, "Time: " . date('c') . "\n");
            fwrite($log_file, "Project Root: " . $projectRoot . "\n\n");
        }
        // --- END DEBUGGING ---

        // 1. Fetch data for the specific tab from the main DB
        $tab_stmt = $pdo->prepare("SELECT * FROM tabs WHERE id = ?");
        $tab_stmt->execute([$tab_id]);
        $tab = $tab_stmt->fetch(PDO::FETCH_ASSOC);

        if (!$tab) {
            throw new Exception("Tab with ID {$tab_id} not found.");
        }

        $cat_stmt = $pdo->prepare("SELECT * FROM categories WHERE tab_id = ?");
        $cat_stmt->execute([$tab_id]);
        $categories = $cat_stmt->fetchAll(PDO::FETCH_ASSOC);

        $book_stmt = $pdo->prepare("SELECT * FROM bookmarks WHERE tab_id = ?");
        $book_stmt->execute([$tab_id]);
        $bookmarks = $book_stmt->fetchAll(PDO::FETCH_ASSOC);
        
        // 2. Create temporary structure and database
        $temp_db_path = $temp_dir . '/database/bookmarkly.db';
        mkdir($temp_dir . '/database', 0777, true);
        mkdir($temp_dir . '/images/custom', 0777, true); // CORRECTED: Create the 'custom' directory
        mkdir($temp_dir . '/images/backgrounds', 0777, true);
        
        $backup_pdo = new PDO('sqlite:' . $temp_db_path);
        $backup_pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        
        // Create schema in backup DB
        $backup_pdo->exec("CREATE TABLE tabs (id INTEGER PRIMARY KEY, name TEXT, background_image_url TEXT, background_brightness INTEGER, background_saturation INTEGER, theme TEXT, theme_transparency INTEGER)");
        $backup_pdo->exec("CREATE TABLE categories (id INTEGER PRIMARY KEY, name TEXT, sort_order INTEGER, tab_id INTEGER)");
        $backup_pdo->exec("CREATE TABLE bookmarks (id INTEGER PRIMARY KEY, category_id INTEGER, title TEXT, url TEXT, icon TEXT, is_favorite INTEGER, sort_order INTEGER, tab_id INTEGER)");

        // 3. Copy files and insert data into backup DB
        
        // Handle Tab Background
        $new_background_path = $tab['background_image_url'];
        if (!empty($tab['background_image_url']) && strpos($tab['background_image_url'], 'data/images/backgrounds/') === 0) {
            $source_path_relative = strtok($tab['background_image_url'], '?');
            $source_path_absolute = $projectRoot . DIRECTORY_SEPARATOR . $source_path_relative;
            if (file_exists($source_path_absolute)) {
                $bg_filename = basename($source_path_relative);
                $new_background_path_in_db = 'images/backgrounds/' . $bg_filename;
                $destination_path = $temp_dir . DIRECTORY_SEPARATOR . $new_background_path_in_db;
                if (copy($source_path_absolute, $destination_path)) {
                    $new_background_path = $new_background_path_in_db;
                }
            }
        }
        
        // Insert Tab data
        $insert_tab_stmt = $backup_pdo->prepare("INSERT INTO tabs VALUES (?, ?, ?, ?, ?, ?, ?)");
        $insert_tab_stmt->execute([$tab['id'], $tab['name'], $new_background_path, $tab['background_brightness'], $tab['background_saturation'], $tab['theme'], $tab['theme_transparency']]);

        // Handle Categories and Bookmarks
        $insert_cat_stmt = $backup_pdo->prepare("INSERT INTO categories VALUES (?, ?, ?, ?)");
        foreach ($categories as $category) {
            $insert_cat_stmt->execute([$category['id'], $category['name'], $category['sort_order'], $category['tab_id']]);
        }

        $insert_book_stmt = $backup_pdo->prepare("INSERT INTO bookmarks VALUES (?, ?, ?, ?, ?, ?, ?, ?)");
        foreach ($bookmarks as $bookmark) {
            $icon_path_for_db = $bookmark['icon']; // Start with the original path

            // Only process locally stored custom icons
            if (!empty($bookmark['icon']) && strpos($bookmark['icon'], 'data/images/custom/') === 0) {
                
                // --- START DEBUGGING ---
                if ($log_file) fwrite($log_file, "Processing bookmark ID: " . $bookmark['id'] . " Title: '" . $bookmark['title'] . "'\n");
                // --- END DEBUGGING ---

                $relative_source_path = strtok($bookmark['icon'], '?');
                $absolute_source_path = $projectRoot . DIRECTORY_SEPARATOR . $relative_source_path;

                // --- START DEBUGGING ---
                if ($log_file) {
                    fwrite($log_file, "  - DB Path: " . $bookmark['icon'] . "\n");
                    fwrite($log_file, "  - Relative Path Used: " . $relative_source_path . "\n");
                    fwrite($log_file, "  - Absolute Path Checked: " . $absolute_source_path . "\n");
                    $file_exists_result = file_exists($absolute_source_path);
                    fwrite($log_file, "  - file_exists() Result: " . ($file_exists_result ? 'TRUE' : 'FALSE') . "\n");
                }
                // --- END DEBUGGING ---

                if ($file_exists_result) {
                    $filename = basename($relative_source_path);
                    
                    // The new path inside the zip archive's structure
                    $relative_dest_path = 'images/custom/' . $filename;
                    
                    // The absolute path to copy the file to in the temp directory
                    $absolute_dest_path = $temp_dir . DIRECTORY_SEPARATOR . $relative_dest_path;

                    // Copy the file and if successful, update the path to be stored in the backup DB
                    if (copy($absolute_source_path, $absolute_dest_path)) {
                        $icon_path_for_db = $relative_dest_path;
                        if ($log_file) fwrite($log_file, "  - ACTION: File copied successfully.\n\n");
                    } else {
                        if ($log_file) fwrite($log_file, "  - ACTION: copy() FAILED.\n\n");
                    }
                } else {
                    if ($log_file) fwrite($log_file, "  - ACTION: File skipped.\n\n");
                }
            }
            $insert_book_stmt->execute([$bookmark['id'], $bookmark['category_id'], $bookmark['title'], $bookmark['url'], $icon_path_for_db, $bookmark['is_favorite'], $bookmark['sort_order'], $bookmark['tab_id']]);
        }
        
        // 4. Create manifest.json
        $manifest = [
            'type' => 'tab',
            'tab_id' => $tab['id'],
            'tab_name' => $tab['name'],
            'version' => '2.0',
            'timestamp' => date('c')
        ];
        file_put_contents($temp_dir . '/manifest.json', json_encode($manifest, JSON_PRETTY_PRINT));
        
        // 5. Zip and send the backup
        $safe_tab_name = preg_replace('/[^a-zA-Z0-9_-]/', '_', $tab['name']);
        $backupFileName = "bookmarkly_tab_{$safe_tab_name}_backup_" . date('Y-m-d') . '.zip';
        $backupFilePath = sys_get_temp_dir() . DIRECTORY_SEPARATOR . $backupFileName;

        if (createZipArchive($temp_dir, $backupFilePath, $error_message)) {
            // --- START DEBUGGING ---
            if ($log_file) {
                fwrite($log_file, "--- Backup zip created successfully. ---");
                fclose($log_file);
            }
            // --- END DEBUGGING ---
            header('Content-Type: application/zip');
            header('Content-Disposition: attachment; filename="' . $backupFileName . '"');
            header('Content-Length: ' . filesize($backupFilePath));
            readfile($backupFilePath);
            unlink($backupFilePath);
            rrmdir($temp_dir);
            exit;
        } else {
            // --- START DEBUGGING ---
            if ($log_file) {
                fwrite($log_file, "--- FAILED to create zip archive. Error: " . $error_message . " ---");
                fclose($log_file);
            }
            // --- END DEBUGGING ---
            throw new Exception('Failed to create zip archive. ' . $error_message);
        }

    } catch (Exception $e) {
        // --- START DEBUGGING ---
        if (isset($log_file) && is_resource($log_file)) {
            fwrite($log_file, "--- CATCH BLOCK ERROR: " . $e->getMessage() . " ---");
            fclose($log_file);
        }
        // --- END DEBUGGING ---
        rrmdir($temp_dir); // Clean up on error
        $_SESSION['flash_message'] = ['text' => 'Error creating tab backup: ' . $e->getMessage(), 'type' => 'danger'];
        header('Location: ../settings.php');
        exit;
    }
}