<?php
/**
 * A1 Tools Import/Export
 *
 * Handles page import and export with Elementor data preservation.
 *
 * @package A1_Tools
 * @since 1.6.6
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Class A1Tools_Import_Export
 *
 * Provides Import/Export functionality for WordPress pages (including Elementor pages).
 *
 * @since 1.6.6
 */
class A1Tools_Import_Export {

	/**
	 * Singleton instance.
	 *
	 * @var A1Tools_Import_Export|null
	 */
	private static $instance = null;

	/**
	 * Elementor meta keys to preserve during export/import.
	 *
	 * @var array
	 */
	private $elementor_meta_keys = array(
		'_elementor_data',
		'_elementor_page_settings',
		'_elementor_version',
		'_elementor_edit_mode',
		'_elementor_template_type',
	);

	/**
	 * Get singleton instance.
	 *
	 * @return A1Tools_Import_Export
	 */
	public static function get_instance() {
		if ( null === self::$instance ) {
			self::$instance = new self();
		}
		return self::$instance;
	}

	/**
	 * Constructor — registers hooks.
	 */
	private function __construct() {
		add_action( 'wp_ajax_a1tools_get_pages_by_author', array( $this, 'ajax_get_pages_by_author' ) );
		add_action( 'wp_ajax_a1tools_export_pages', array( $this, 'ajax_export_pages' ) );
		add_action( 'wp_ajax_a1tools_import_pages', array( $this, 'ajax_import_pages' ) );
		add_action( 'admin_enqueue_scripts', array( $this, 'enqueue_admin_assets' ) );
	}

	// =========================================================================
	// Admin Assets
	// =========================================================================

	/**
	 * Enqueue admin CSS and JS on the Import/Export page only.
	 *
	 * @param string $hook The admin page hook.
	 */
	public function enqueue_admin_assets( $hook ) {
		if ( 'a1-tools_page_a1-tools-import-export' !== $hook ) {
			return;
		}

		wp_register_style( 'a1tools-import-export', false, array(), A1TOOLS_VERSION );
		wp_enqueue_style( 'a1tools-import-export' );
		wp_add_inline_style( 'a1tools-import-export', $this->get_admin_css() );

		wp_register_script( 'a1tools-import-export', false, array( 'jquery' ), A1TOOLS_VERSION, true );
		wp_enqueue_script( 'a1tools-import-export' );

		wp_localize_script( 'a1tools-import-export', 'a1toolsIE', array(
			'ajaxUrl'     => admin_url( 'admin-ajax.php' ),
			'noncePages'  => wp_create_nonce( 'a1tools_get_pages' ),
			'nonceExport' => wp_create_nonce( 'a1tools_export' ),
			'nonceImport' => wp_create_nonce( 'a1tools_import' ),
		) );

		wp_add_inline_script( 'a1tools-import-export', $this->get_admin_js() );
	}

	// =========================================================================
	// AJAX: Get Pages by Author
	// =========================================================================

	/**
	 * AJAX handler — return pages filtered by author.
	 */
	public function ajax_get_pages_by_author() {
		check_ajax_referer( 'a1tools_get_pages', 'nonce' );

		if ( ! current_user_can( 'manage_options' ) ) {
			wp_send_json_error( array( 'message' => __( 'Permission denied.', 'a1-tools' ) ) );
		}

		$author_id = isset( $_POST['author_id'] ) ? absint( $_POST['author_id'] ) : 0;

		$args = array(
			'post_type'   => 'page',
			'post_status' => array( 'publish', 'draft', 'private' ),
			'numberposts' => -1,
			'orderby'     => 'title',
			'order'       => 'ASC',
		);

		if ( $author_id > 0 ) {
			$args['author'] = $author_id;
		}

		$posts = get_posts( $args );
		$pages = array();

		foreach ( $posts as $post ) {
			$elementor_data = get_post_meta( $post->ID, '_elementor_data', true );
			$pages[]        = array(
				'id'            => $post->ID,
				'title'         => $post->post_title,
				'status'        => $post->post_status,
				'date'          => get_the_date( 'Y-m-d', $post ),
				'has_elementor' => ! empty( $elementor_data ),
			);
		}

		wp_send_json_success( array( 'pages' => $pages ) );
	}

	// =========================================================================
	// AJAX: Export Pages
	// =========================================================================

	/**
	 * AJAX handler — export selected pages as JSON or WXR.
	 */
	public function ajax_export_pages() {
		check_ajax_referer( 'a1tools_export', 'nonce' );

		if ( ! current_user_can( 'manage_options' ) ) {
			wp_send_json_error( array( 'message' => __( 'Permission denied.', 'a1-tools' ) ) );
		}

		$page_ids = isset( $_POST['page_ids'] ) ? array_map( 'absint', (array) $_POST['page_ids'] ) : array();
		$format   = isset( $_POST['format'] ) ? sanitize_text_field( wp_unslash( $_POST['format'] ) ) : 'json';

		if ( empty( $page_ids ) ) {
			wp_send_json_error( array( 'message' => __( 'No pages selected.', 'a1-tools' ) ) );
		}

		if ( ! in_array( $format, array( 'json', 'wxr' ), true ) ) {
			wp_send_json_error( array( 'message' => __( 'Invalid format.', 'a1-tools' ) ) );
		}

		$site_name = sanitize_file_name( get_bloginfo( 'name' ) );
		$date      = gmdate( 'Y-m-d' );

		if ( 'json' === $format ) {
			$data     = $this->export_json( $page_ids );
			$filename = "a1tools-export-{$site_name}-{$date}.json";
			$content  = wp_json_encode( $data, JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE );
			$mime     = 'application/json';
		} else {
			$content  = $this->export_wxr( $page_ids );
			$filename = "a1tools-export-{$site_name}-{$date}.xml";
			$mime     = 'text/xml';
		}

		wp_send_json_success( array(
			'filename' => $filename,
			'content'  => $content,
			'mime'     => $mime,
		) );
	}

	// =========================================================================
	// AJAX: Import Pages
	// =========================================================================

	/**
	 * AJAX handler — import pages from uploaded file.
	 */
	public function ajax_import_pages() {
		check_ajax_referer( 'a1tools_import', 'nonce' );

		if ( ! current_user_can( 'manage_options' ) ) {
			wp_send_json_error( array( 'message' => __( 'Permission denied.', 'a1-tools' ) ) );
		}

		if ( empty( $_FILES['import_file'] ) ) {
			wp_send_json_error( array( 'message' => __( 'No file uploaded.', 'a1-tools' ) ) );
		}

		$file       = $_FILES['import_file']; // phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized -- file array handled by validate_upload()
		$validation = $this->validate_upload( $file );

		if ( is_wp_error( $validation ) ) {
			wp_send_json_error( array( 'message' => $validation->get_error_message() ) );
		}

		$duplicate_handling = isset( $_POST['duplicate_handling'] )
			? sanitize_text_field( wp_unslash( $_POST['duplicate_handling'] ) )
			: 'skip';

		if ( ! in_array( $duplicate_handling, array( 'skip', 'create_new', 'update_existing' ), true ) ) {
			$duplicate_handling = 'skip';
		}

		$author_id      = isset( $_POST['author_id'] ) ? absint( $_POST['author_id'] ) : 0;
		$parent_page_id = isset( $_POST['parent_page_id'] ) ? absint( $_POST['parent_page_id'] ) : 0;

		$ext = strtolower( pathinfo( $file['name'], PATHINFO_EXTENSION ) );

		if ( 'json' === $ext ) {
			$results = $this->import_json( $file['tmp_name'], $duplicate_handling, $author_id, $parent_page_id );
		} elseif ( 'xml' === $ext ) {
			$results = $this->import_wxr( $file['tmp_name'], $duplicate_handling, $author_id, $parent_page_id );
		} else {
			wp_send_json_error( array( 'message' => __( 'Unsupported file format. Use .json or .xml.', 'a1-tools' ) ) );
			return;
		}

		if ( is_wp_error( $results ) ) {
			wp_send_json_error( array( 'message' => $results->get_error_message() ) );
			return;
		}

		wp_send_json_success( $results );
	}

	// =========================================================================
	// Export Helpers
	// =========================================================================

	/**
	 * Build export data for a single page.
	 *
	 * @param int $post_id The page ID.
	 * @return array|null Page data array or null on failure.
	 */
	private function get_post_export_data( $post_id ) {
		$post = get_post( $post_id );

		if ( ! $post || 'page' !== $post->post_type ) {
			return null;
		}

		$data = array(
			'post_title'     => $post->post_title,
			'post_content'   => $post->post_content,
			'post_excerpt'   => $post->post_excerpt,
			'post_status'    => $post->post_status,
			'post_name'      => $post->post_name,
			'post_parent'    => $post->post_parent,
			'menu_order'     => $post->menu_order,
			'comment_status' => $post->comment_status,
			'ping_status'    => $post->ping_status,
			'post_date'      => $post->post_date,
			'post_date_gmt'  => $post->post_date_gmt,
			'meta'           => array(),
		);

		// Capture all post meta (skip internal keys).
		$skip_keys    = array( '_edit_lock', '_edit_last' );
		$all_meta     = get_post_meta( $post_id );

		foreach ( $all_meta as $key => $values ) {
			if ( in_array( $key, $skip_keys, true ) ) {
				continue;
			}
			$data['meta'][ $key ] = maybe_unserialize( $values[0] );
		}

		return $data;
	}

	/**
	 * Generate JSON export data.
	 *
	 * @param array $post_ids Array of page IDs.
	 * @return array Export data structure.
	 */
	private function export_json( $post_ids ) {
		$export = array(
			'version'     => A1TOOLS_VERSION,
			'export_date' => gmdate( 'Y-m-d H:i:s' ),
			'site_url'    => site_url(),
			'site_name'   => get_bloginfo( 'name' ),
			'format'      => 'a1tools-json',
			'pages'       => array(),
		);

		foreach ( $post_ids as $post_id ) {
			$page_data = $this->get_post_export_data( $post_id );
			if ( $page_data ) {
				$export['pages'][] = $page_data;
			}
		}

		return $export;
	}

	/**
	 * Generate WXR (WordPress eXtended RSS) export string.
	 *
	 * @param array $post_ids Array of page IDs.
	 * @return string WXR XML string.
	 */
	private function export_wxr( $post_ids ) {
		$site_url  = site_url();
		$site_name = get_bloginfo( 'name' );

		$xml  = '<?xml version="1.0" encoding="UTF-8" ?>' . "\n";
		$xml .= '<rss version="2.0"' . "\n";
		$xml .= '  xmlns:excerpt="http://wordpress.org/export/1.2/excerpt/"' . "\n";
		$xml .= '  xmlns:content="http://purl.org/rss/1.0/modules/content/"' . "\n";
		$xml .= '  xmlns:wfw="http://wellformedweb.org/CommentAPI/"' . "\n";
		$xml .= '  xmlns:dc="http://purl.org/dc/elements/1.1/"' . "\n";
		$xml .= '  xmlns:wp="http://wordpress.org/export/1.2/"' . "\n";
		$xml .= '>' . "\n";
		$xml .= '<channel>' . "\n";
		$xml .= '  <title>' . $this->esc_xml( $site_name ) . '</title>' . "\n";
		$xml .= '  <link>' . esc_url( $site_url ) . '</link>' . "\n";
		$xml .= '  <description>A1 Tools Page Export</description>' . "\n";
		$xml .= '  <wp:wxr_version>1.2</wp:wxr_version>' . "\n";
		$xml .= '  <wp:base_site_url>' . esc_url( $site_url ) . '</wp:base_site_url>' . "\n";
		$xml .= '  <wp:base_blog_url>' . esc_url( home_url() ) . '</wp:base_blog_url>' . "\n";
		$xml .= '  <generator>A1 Tools ' . $this->esc_xml( A1TOOLS_VERSION ) . '</generator>' . "\n";

		foreach ( $post_ids as $post_id ) {
			$page_data = $this->get_post_export_data( $post_id );
			if ( ! $page_data ) {
				continue;
			}

			$author_login = get_the_author_meta( 'login', get_post_field( 'post_author', $post_id ) );

			$xml .= '  <item>' . "\n";
			$xml .= '    <title>' . $this->esc_xml( $page_data['post_title'] ) . '</title>' . "\n";
			$xml .= '    <dc:creator><![CDATA[' . $author_login . ']]></dc:creator>' . "\n";
			$xml .= '    <content:encoded><![CDATA[' . $page_data['post_content'] . ']]></content:encoded>' . "\n";
			$xml .= '    <excerpt:encoded><![CDATA[' . $page_data['post_excerpt'] . ']]></excerpt:encoded>' . "\n";
			$xml .= '    <wp:post_date>' . $this->esc_xml( $page_data['post_date'] ) . '</wp:post_date>' . "\n";
			$xml .= '    <wp:post_date_gmt>' . $this->esc_xml( $page_data['post_date_gmt'] ) . '</wp:post_date_gmt>' . "\n";
			$xml .= '    <wp:post_name>' . $this->esc_xml( $page_data['post_name'] ) . '</wp:post_name>' . "\n";
			$xml .= '    <wp:status>' . $this->esc_xml( $page_data['post_status'] ) . '</wp:status>' . "\n";
			$xml .= '    <wp:post_parent>' . absint( $page_data['post_parent'] ) . '</wp:post_parent>' . "\n";
			$xml .= '    <wp:menu_order>' . intval( $page_data['menu_order'] ) . '</wp:menu_order>' . "\n";
			$xml .= '    <wp:post_type>page</wp:post_type>' . "\n";
			$xml .= '    <wp:comment_status>' . $this->esc_xml( $page_data['comment_status'] ) . '</wp:comment_status>' . "\n";

			foreach ( $page_data['meta'] as $meta_key => $meta_value ) {
				$serialized = maybe_serialize( $meta_value );
				$xml .= '    <wp:postmeta>' . "\n";
				$xml .= '      <wp:meta_key><![CDATA[' . $meta_key . ']]></wp:meta_key>' . "\n";
				$xml .= '      <wp:meta_value><![CDATA[' . $serialized . ']]></wp:meta_value>' . "\n";
				$xml .= '    </wp:postmeta>' . "\n";
			}

			$xml .= '  </item>' . "\n";
		}

		$xml .= '</channel>' . "\n";
		$xml .= '</rss>' . "\n";

		return $xml;
	}

	/**
	 * XML-escape a string. Uses esc_xml() if available (WP 5.5+), else esc_html().
	 *
	 * @param string $value The string to escape.
	 * @return string Escaped string.
	 */
	private function esc_xml( $value ) {
		if ( function_exists( 'esc_xml' ) ) {
			return esc_xml( $value );
		}
		return esc_html( $value );
	}

	// =========================================================================
	// Import Helpers
	// =========================================================================

	/**
	 * Validate an uploaded file.
	 *
	 * @param array $file The $_FILES entry.
	 * @return true|WP_Error True on success, WP_Error on failure.
	 */
	private function validate_upload( $file ) {
		if ( $file['error'] !== UPLOAD_ERR_OK ) {
			return new WP_Error( 'upload_error', __( 'File upload failed.', 'a1-tools' ) );
		}

		$ext = strtolower( pathinfo( $file['name'], PATHINFO_EXTENSION ) );
		if ( ! in_array( $ext, array( 'json', 'xml' ), true ) ) {
			return new WP_Error( 'invalid_type', __( 'Only .json and .xml files are allowed.', 'a1-tools' ) );
		}

		if ( $file['size'] > 50 * 1024 * 1024 ) {
			return new WP_Error( 'file_too_large', __( 'File exceeds maximum size of 50 MB.', 'a1-tools' ) );
		}

		if ( ! is_readable( $file['tmp_name'] ) ) {
			return new WP_Error( 'not_readable', __( 'Uploaded file is not readable.', 'a1-tools' ) );
		}

		if ( 'json' === $ext ) {
			$content = file_get_contents( $file['tmp_name'] ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents
			$decoded = json_decode( $content, true );
			if ( null === $decoded ) {
				return new WP_Error( 'invalid_json', __( 'File contains invalid JSON.', 'a1-tools' ) );
			}
			if ( ! isset( $decoded['format'] ) || 'a1tools-json' !== $decoded['format'] ) {
				return new WP_Error( 'invalid_format', __( 'This JSON file was not exported by A1 Tools.', 'a1-tools' ) );
			}
		}

		if ( 'xml' === $ext ) {
			$content = file_get_contents( $file['tmp_name'] ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents
			if ( strpos( $content, 'xmlns:wp=' ) === false ) {
				return new WP_Error( 'invalid_wxr', __( 'This XML file does not appear to be a valid WordPress export.', 'a1-tools' ) );
			}
		}

		return true;
	}

	/**
	 * Import pages from a JSON file.
	 *
	 * @param string $file_path Path to the JSON file.
	 * @param string $duplicate_handling How to handle duplicates: skip, create_new, update_existing.
	 * @param int    $author_id Author ID to assign to imported pages (0 = keep default).
	 * @param int    $parent_page_id Parent page ID to assign to all imported pages (0 = keep original).
	 * @return array|WP_Error Results array or error.
	 */
	private function import_json( $file_path, $duplicate_handling, $author_id = 0, $parent_page_id = 0 ) {
		$content = file_get_contents( $file_path ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents
		$data    = json_decode( $content, true );

		if ( ! isset( $data['pages'] ) || ! is_array( $data['pages'] ) ) {
			return new WP_Error( 'invalid_data', __( 'No pages found in import file.', 'a1-tools' ) );
		}

		return $this->process_import( $data['pages'], $duplicate_handling, $author_id, $parent_page_id );
	}

	/**
	 * Import pages from a WXR (WordPress XML) file.
	 *
	 * @param string $file_path Path to the XML file.
	 * @param string $duplicate_handling How to handle duplicates.
	 * @param int    $author_id Author ID to assign to imported pages (0 = keep default).
	 * @param int    $parent_page_id Parent page ID to assign to all imported pages (0 = keep original).
	 * @return array|WP_Error Results array or error.
	 */
	private function import_wxr( $file_path, $duplicate_handling, $author_id = 0, $parent_page_id = 0 ) {
		$xml_content = file_get_contents( $file_path ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents

		libxml_use_internal_errors( true );
		$xml = simplexml_load_string( $xml_content );

		if ( false === $xml ) {
			return new WP_Error( 'xml_parse_error', __( 'Failed to parse XML file.', 'a1-tools' ) );
		}

		$namespaces = $xml->getNamespaces( true );
		$wp_ns      = isset( $namespaces['wp'] ) ? $namespaces['wp'] : 'http://wordpress.org/export/1.2/';
		$content_ns = isset( $namespaces['content'] ) ? $namespaces['content'] : 'http://purl.org/rss/1.0/modules/content/';
		$excerpt_ns = isset( $namespaces['excerpt'] ) ? $namespaces['excerpt'] : 'http://wordpress.org/export/1.2/excerpt/';

		$pages = array();

		foreach ( $xml->channel->item as $item ) {
			$wp      = $item->children( $wp_ns );
			$content = $item->children( $content_ns );
			$excerpt = $item->children( $excerpt_ns );

			// Only import pages.
			if ( isset( $wp->post_type ) && 'page' !== (string) $wp->post_type ) {
				continue;
			}

			$page_data = array(
				'post_title'     => (string) $item->title,
				'post_content'   => (string) $content->encoded,
				'post_excerpt'   => isset( $excerpt->encoded ) ? (string) $excerpt->encoded : '',
				'post_status'    => (string) $wp->status,
				'post_name'      => (string) $wp->post_name,
				'post_parent'    => (int) $wp->post_parent,
				'menu_order'     => (int) $wp->menu_order,
				'comment_status' => (string) $wp->comment_status,
				'post_date'      => (string) $wp->post_date,
				'post_date_gmt'  => (string) $wp->post_date_gmt,
				'meta'           => array(),
			);

			if ( isset( $wp->postmeta ) ) {
				foreach ( $wp->postmeta as $meta ) {
					$meta_key   = (string) $meta->meta_key;
					$meta_value = (string) $meta->meta_value;
					$page_data['meta'][ $meta_key ] = maybe_unserialize( $meta_value );
				}
			}

			$pages[] = $page_data;
		}

		if ( empty( $pages ) ) {
			return new WP_Error( 'no_pages', __( 'No pages found in the import file.', 'a1-tools' ) );
		}

		return $this->process_import( $pages, $duplicate_handling, $author_id, $parent_page_id );
	}

	/**
	 * Process an array of page data for import.
	 *
	 * @param array  $pages Array of page data arrays.
	 * @param string $duplicate_handling How to handle duplicates.
	 * @param int    $author_id Author ID to assign to imported pages (0 = keep default).
	 * @param int    $parent_page_id Parent page ID to assign to all imported pages (0 = keep original).
	 * @return array Results summary.
	 */
	private function process_import( $pages, $duplicate_handling, $author_id = 0, $parent_page_id = 0 ) {
		$results = array(
			'imported' => 0,
			'updated'  => 0,
			'skipped'  => 0,
			'errors'   => 0,
			'details'  => array(),
		);

		foreach ( $pages as $page_data ) {
			$result             = $this->import_single_page( $page_data, $duplicate_handling, $author_id, $parent_page_id );
			$results['details'][] = $result;

			switch ( $result['action'] ) {
				case 'imported':
					$results['imported']++;
					break;
				case 'updated':
					$results['updated']++;
					break;
				case 'skipped':
					$results['skipped']++;
					break;
				default:
					$results['errors']++;
					break;
			}
		}

		return $results;
	}

	/**
	 * Find an existing page by slug or title.
	 *
	 * @param array $page_data The page data array.
	 * @return int Existing page ID or 0 if not found.
	 */
	private function find_existing_page( $page_data ) {
		// Try by slug first.
		if ( ! empty( $page_data['post_name'] ) ) {
			$existing = get_page_by_path( $page_data['post_name'], OBJECT, 'page' );
			if ( $existing ) {
				return $existing->ID;
			}
		}

		// Fallback: query by title.
		if ( ! empty( $page_data['post_title'] ) ) {
			$query = new WP_Query( array(
				'post_type'      => 'page',
				'title'          => $page_data['post_title'],
				'posts_per_page' => 1,
				'fields'         => 'ids',
				'post_status'    => array( 'publish', 'draft', 'private', 'pending', 'trash' ),
			) );
			if ( $query->have_posts() ) {
				return $query->posts[0];
			}
		}

		return 0;
	}

	/**
	 * Import a single page.
	 *
	 * @param array  $page_data The page data array.
	 * @param string $duplicate_handling How to handle duplicates.
	 * @param int    $author_id Author ID to assign (0 = keep default).
	 * @param int    $parent_page_id Parent page ID to assign (0 = keep original from export data).
	 * @return array Result with action, title, and message.
	 */
	private function import_single_page( $page_data, $duplicate_handling, $author_id = 0, $parent_page_id = 0 ) {
		$title       = isset( $page_data['post_title'] ) ? $page_data['post_title'] : '';
		$existing_id = $this->find_existing_page( $page_data );

		// Handle duplicates.
		if ( $existing_id > 0 ) {
			if ( 'skip' === $duplicate_handling ) {
				return array(
					'action'  => 'skipped',
					'title'   => $title,
					'message' => sprintf(
						/* translators: %s: page title */
						__( 'Page "%s" already exists. Skipped.', 'a1-tools' ),
						$title
					),
				);
			}

			if ( 'update_existing' === $duplicate_handling ) {
				$update_data = array(
					'ID'             => $existing_id,
					'post_title'     => $title,
					'post_content'   => isset( $page_data['post_content'] ) ? $page_data['post_content'] : '',
					'post_excerpt'   => isset( $page_data['post_excerpt'] ) ? $page_data['post_excerpt'] : '',
					'post_status'    => isset( $page_data['post_status'] ) ? $page_data['post_status'] : 'draft',
					'post_name'      => isset( $page_data['post_name'] ) ? $page_data['post_name'] : '',
					'menu_order'     => isset( $page_data['menu_order'] ) ? intval( $page_data['menu_order'] ) : 0,
					'comment_status' => isset( $page_data['comment_status'] ) ? $page_data['comment_status'] : 'closed',
				);

				if ( $author_id > 0 ) {
					$update_data['post_author'] = $author_id;
				}

				// Apply parent page override if specified, otherwise keep original from export.
				if ( $parent_page_id > 0 ) {
					$update_data['post_parent'] = $parent_page_id;
				} elseif ( isset( $page_data['post_parent'] ) ) {
					$update_data['post_parent'] = intval( $page_data['post_parent'] );
				}

				$result = wp_update_post( $update_data, true );

				if ( is_wp_error( $result ) ) {
					return array(
						'action'  => 'error',
						'title'   => $title,
						'message' => $result->get_error_message(),
					);
				}

				$this->import_page_meta( $existing_id, $page_data );

				return array(
					'action'  => 'updated',
					'title'   => $title,
					'post_id' => $existing_id,
					'message' => sprintf(
						/* translators: %s: page title */
						__( 'Page "%s" updated successfully.', 'a1-tools' ),
						$title
					),
				);
			}

			// 'create_new' — fall through to insert below.
		}

		// Insert new page.
		$post_data = array(
			'post_title'     => $title,
			'post_content'   => isset( $page_data['post_content'] ) ? $page_data['post_content'] : '',
			'post_excerpt'   => isset( $page_data['post_excerpt'] ) ? $page_data['post_excerpt'] : '',
			'post_status'    => isset( $page_data['post_status'] ) ? $page_data['post_status'] : 'draft',
			'post_type'      => 'page',
			'post_name'      => isset( $page_data['post_name'] ) ? $page_data['post_name'] : '',
			'menu_order'     => isset( $page_data['menu_order'] ) ? intval( $page_data['menu_order'] ) : 0,
			'comment_status' => isset( $page_data['comment_status'] ) ? $page_data['comment_status'] : 'closed',
		);

		if ( $author_id > 0 ) {
			$post_data['post_author'] = $author_id;
		}

		// Apply parent page override if specified, otherwise keep original from export.
		if ( $parent_page_id > 0 ) {
			$post_data['post_parent'] = $parent_page_id;
		} elseif ( isset( $page_data['post_parent'] ) ) {
			$post_data['post_parent'] = intval( $page_data['post_parent'] );
		}

		// Let WordPress auto-generate slug if creating duplicate.
		if ( $existing_id > 0 && 'create_new' === $duplicate_handling ) {
			$post_data['post_name'] = '';
		}

		$new_id = wp_insert_post( $post_data, true );

		if ( is_wp_error( $new_id ) ) {
			return array(
				'action'  => 'error',
				'title'   => $title,
				'message' => $new_id->get_error_message(),
			);
		}

		$this->import_page_meta( $new_id, $page_data );

		return array(
			'action'  => 'imported',
			'title'   => $title,
			'post_id' => $new_id,
			'message' => sprintf(
				/* translators: %s: page title */
				__( 'Page "%s" imported successfully.', 'a1-tools' ),
				$title
			),
		);
	}

	/**
	 * Import meta data for a page with Elementor double-serialization fix.
	 *
	 * @param int   $post_id The page ID.
	 * @param array $page_data The page data array containing a 'meta' key.
	 */
	private function import_page_meta( $post_id, $page_data ) {
		if ( empty( $page_data['meta'] ) || ! is_array( $page_data['meta'] ) ) {
			return;
		}

		$skip_keys = array( '_edit_lock', '_edit_last' );

		foreach ( $page_data['meta'] as $meta_key => $meta_value ) {
			if ( in_array( $meta_key, $skip_keys, true ) ) {
				continue;
			}

			// CRITICAL: Elementor _elementor_data is stored as a JSON string.
			// WordPress's update_post_meta() internally calls wp_unslash() which
			// strips backslashes from the JSON. We must use wp_slash() to counteract this.
			if ( '_elementor_data' === $meta_key ) {
				if ( is_array( $meta_value ) ) {
					$meta_value = wp_json_encode( $meta_value );
				}
				update_post_meta( $post_id, $meta_key, wp_slash( $meta_value ) );
			} else {
				update_post_meta( $post_id, $meta_key, $meta_value );
			}
		}
	}

	// =========================================================================
	// Admin Page Render
	// =========================================================================

	/**
	 * Build the HTML for the page checkbox list.
	 *
	 * @param array $posts Array of WP_Post objects.
	 * @return string HTML string.
	 */
	private function build_page_list_html( $posts ) {
		if ( empty( $posts ) ) {
			return '<p class="description">' . esc_html__( 'No pages found.', 'a1-tools' ) . '</p>';
		}

		$html = '<div class="a1tools-page-checkboxes">';
		foreach ( $posts as $post ) {
			$elementor_data = get_post_meta( $post->ID, '_elementor_data', true );
			$has_elementor  = ! empty( $elementor_data );

			$badge  = $has_elementor ? ' <span class="a1tools-elementor-badge">Elementor</span>' : '';
			$status = '';
			if ( 'publish' !== $post->post_status ) {
				$status = ' <span class="a1tools-status-badge a1tools-status-' . esc_attr( $post->post_status ) . '">' . esc_html( $post->post_status ) . '</span>';
			}

			$title = ! empty( $post->post_title ) ? esc_html( $post->post_title ) : esc_html__( '(no title)', 'a1-tools' );

			$html .= '<label class="a1tools-page-item">';
			$html .= '<input type="checkbox" name="a1tools_page_ids[]" value="' . esc_attr( $post->ID ) . '" />';
			$html .= ' ' . $title . $badge . $status;
			$html .= '</label>';
		}
		$html .= '</div>';

		return $html;
	}

	/**
	 * Render the Import/Export admin page.
	 */
	public function render_page() {
		// Pre-load all pages server-side for instant display.
		$all_pages = get_posts( array(
			'post_type'   => 'page',
			'post_status' => array( 'publish', 'draft', 'private' ),
			'numberposts' => -1,
			'orderby'     => 'title',
			'order'       => 'ASC',
		) );
		$page_count = count( $all_pages );
		?>
		<div class="wrap">
			<h1><?php esc_html_e( 'Import / Export Pages', 'a1-tools' ); ?></h1>
			<p><?php esc_html_e( 'Export pages with all content and Elementor data, or import pages from a previous export.', 'a1-tools' ); ?></p>

			<!-- EXPORT SECTION -->
			<div class="a1tools-ie-section">
				<h2><?php esc_html_e( 'Export Pages', 'a1-tools' ); ?></h2>

				<table class="form-table">
					<tr>
						<th scope="row">
							<label for="a1tools-export-author"><?php esc_html_e( 'Filter by Author', 'a1-tools' ); ?></label>
						</th>
						<td>
							<?php
							wp_dropdown_users( array(
								'name'            => 'a1tools_export_author',
								'id'              => 'a1tools-export-author',
								'show_option_all' => __( 'All Authors', 'a1-tools' ),
							) );
							?>
						</td>
					</tr>
					<tr>
						<th scope="row"><?php esc_html_e( 'Select Pages', 'a1-tools' ); ?></th>
						<td>
							<div id="a1tools-page-list-controls" style="margin-bottom: 10px;<?php echo $page_count > 0 ? '' : ' display: none;'; ?>">
								<button type="button" class="button" id="a1tools-select-all"><?php esc_html_e( 'Select All', 'a1-tools' ); ?></button>
								<button type="button" class="button" id="a1tools-deselect-all"><?php esc_html_e( 'Deselect All', 'a1-tools' ); ?></button>
								<span id="a1tools-page-count" style="margin-left: 10px; color: #666;">
									<?php
									/* translators: %d: number of pages */
									echo esc_html( sprintf( _n( '%d page', '%d pages', $page_count, 'a1-tools' ), $page_count ) );
									?>
								</span>
							</div>
							<div id="a1tools-page-list">
								<?php
								// phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped -- HTML built with esc_html/esc_attr above.
								echo $this->build_page_list_html( $all_pages );
								?>
							</div>
							<div id="a1tools-page-list-spinner" class="a1tools-spinner-wrap" style="display: none;">
								<span class="a1tools-spinner"></span>
								<span><?php esc_html_e( 'Loading pages...', 'a1-tools' ); ?></span>
							</div>
						</td>
					</tr>
					<tr>
						<th scope="row">
							<label for="a1tools-export-format"><?php esc_html_e( 'Export Format', 'a1-tools' ); ?></label>
						</th>
						<td>
							<select id="a1tools-export-format">
								<option value="json"><?php esc_html_e( 'JSON (.json) — preserves all data exactly', 'a1-tools' ); ?></option>
								<option value="wxr"><?php esc_html_e( 'WordPress XML / WXR (.xml) — standard WP format', 'a1-tools' ); ?></option>
							</select>
						</td>
					</tr>
				</table>

				<p>
					<button type="button" class="button button-primary" id="a1tools-export-btn">
						<?php esc_html_e( 'Export Selected Pages', 'a1-tools' ); ?>
					</button>
					<span id="a1tools-export-status" class="a1tools-status-msg" style="margin-left: 10px;"></span>
				</p>
				<div id="a1tools-export-progress" class="a1tools-progress-wrap" style="display: none;">
					<div class="a1tools-progress-bar">
						<div class="a1tools-progress-fill" id="a1tools-export-progress-fill"></div>
					</div>
					<span class="a1tools-progress-text" id="a1tools-export-progress-text"></span>
				</div>
			</div>

			<hr />

			<!-- IMPORT SECTION -->
			<div class="a1tools-ie-section">
				<h2><?php esc_html_e( 'Import Pages', 'a1-tools' ); ?></h2>

				<table class="form-table">
					<tr>
						<th scope="row">
							<label for="a1tools-import-file"><?php esc_html_e( 'Upload File', 'a1-tools' ); ?></label>
						</th>
						<td>
							<input type="file" id="a1tools-import-file" accept=".json,.xml" />
							<p class="description"><?php esc_html_e( 'Accepts .json or .xml files exported from A1 Tools or WordPress.', 'a1-tools' ); ?></p>
						</td>
					</tr>
					<tr>
						<th scope="row">
							<label for="a1tools-import-author"><?php esc_html_e( 'Assign Author', 'a1-tools' ); ?></label>
						</th>
						<td>
							<?php
							wp_dropdown_users( array(
								'name' => 'a1tools_import_author',
								'id'   => 'a1tools-import-author',
							) );
							?>
							<p class="description"><?php esc_html_e( 'All imported pages will be assigned to this author.', 'a1-tools' ); ?></p>
						</td>
					</tr>
					<tr>
						<th scope="row">
							<label for="a1tools-import-parent"><?php esc_html_e( 'Parent Page', 'a1-tools' ); ?></label>
						</th>
						<td>
							<?php
							wp_dropdown_pages( array(
								'name'             => 'a1tools_import_parent',
								'id'               => 'a1tools-import-parent',
								'show_option_none' => esc_html__( '(no parent)', 'a1-tools' ),
								'option_none_value' => '0',
								'sort_column'      => 'menu_order, post_title',
							) );
							?>
							<p class="description"><?php esc_html_e( 'Assign all imported pages as children of this page. Leave as "(no parent)" to keep original hierarchy.', 'a1-tools' ); ?></p>
						</td>
					</tr>
					<tr>
						<th scope="row">
							<label for="a1tools-duplicate-handling"><?php esc_html_e( 'If Page Exists', 'a1-tools' ); ?></label>
						</th>
						<td>
							<select id="a1tools-duplicate-handling">
								<option value="skip"><?php esc_html_e( 'Skip (do not import)', 'a1-tools' ); ?></option>
								<option value="create_new"><?php esc_html_e( 'Create New (with unique slug)', 'a1-tools' ); ?></option>
								<option value="update_existing"><?php esc_html_e( 'Update Existing (overwrite content & meta)', 'a1-tools' ); ?></option>
							</select>
							<p class="description"><?php esc_html_e( 'How to handle pages that already exist on this site (matched by slug or title).', 'a1-tools' ); ?></p>
						</td>
					</tr>
				</table>

				<p>
					<button type="button" class="button button-primary" id="a1tools-import-btn">
						<?php esc_html_e( 'Import Pages', 'a1-tools' ); ?>
					</button>
					<span id="a1tools-import-status" class="a1tools-status-msg" style="margin-left: 10px;"></span>
				</p>
				<div id="a1tools-import-progress" class="a1tools-progress-wrap" style="display: none;">
					<div class="a1tools-progress-bar">
						<div class="a1tools-progress-fill" id="a1tools-import-progress-fill"></div>
					</div>
					<span class="a1tools-progress-text" id="a1tools-import-progress-text"></span>
				</div>

				<div id="a1tools-import-results" style="display: none;">
					<h3><?php esc_html_e( 'Import Results', 'a1-tools' ); ?></h3>
					<div id="a1tools-import-summary"></div>
					<div id="a1tools-import-details"></div>
				</div>
			</div>
		</div>
		<?php
	}

	// =========================================================================
	// Inline CSS
	// =========================================================================

	/**
	 * Return admin CSS for the Import/Export page.
	 *
	 * @return string CSS string.
	 */
	private function get_admin_css() {
		return '
.a1tools-ie-section {
	max-width: 900px;
	margin-bottom: 30px;
}
.a1tools-page-checkboxes {
	max-height: 400px;
	overflow-y: auto;
	border: 1px solid #ddd;
	background: #fff;
	padding: 10px;
	border-radius: 4px;
}
.a1tools-page-item {
	display: block;
	padding: 6px 8px;
	margin: 0;
	cursor: pointer;
	border-bottom: 1px solid #f0f0f0;
}
.a1tools-page-item:last-child {
	border-bottom: none;
}
.a1tools-page-item:hover {
	background: #f7f7f7;
}
.a1tools-page-item input[type="checkbox"] {
	margin-right: 8px;
}
.a1tools-elementor-badge {
	display: inline-block;
	background: #93003c;
	color: #fff;
	font-size: 10px;
	padding: 1px 6px;
	border-radius: 3px;
	margin-left: 6px;
	vertical-align: middle;
	text-transform: uppercase;
	font-weight: 600;
}
.a1tools-status-badge {
	display: inline-block;
	font-size: 10px;
	padding: 1px 6px;
	border-radius: 3px;
	margin-left: 4px;
	vertical-align: middle;
	text-transform: uppercase;
	font-weight: 600;
}
.a1tools-status-draft {
	background: #f0c33c;
	color: #333;
}
.a1tools-status-private {
	background: #607d8b;
	color: #fff;
}
/* Spinner */
.a1tools-spinner-wrap {
	display: flex;
	align-items: center;
	gap: 10px;
	padding: 12px 0;
	color: #666;
}
.a1tools-spinner {
	display: inline-block;
	width: 20px;
	height: 20px;
	border: 3px solid #ddd;
	border-top-color: #0073aa;
	border-radius: 50%;
	animation: a1tools-spin 0.7s linear infinite;
}
@keyframes a1tools-spin {
	to { transform: rotate(360deg); }
}
/* Progress bar */
.a1tools-progress-wrap {
	margin: 12px 0;
	max-width: 500px;
}
.a1tools-progress-bar {
	height: 22px;
	background: #e0e0e0;
	border-radius: 11px;
	overflow: hidden;
	position: relative;
}
.a1tools-progress-fill {
	height: 100%;
	background: linear-gradient(90deg, #0073aa, #00a0d2);
	border-radius: 11px;
	width: 0%;
	transition: width 0.3s ease;
}
.a1tools-progress-fill.a1tools-indeterminate {
	width: 30% !important;
	animation: a1tools-indeterminate 1.5s ease-in-out infinite;
}
@keyframes a1tools-indeterminate {
	0%   { margin-left: 0;   width: 30%; }
	50%  { margin-left: 35%; width: 35%; }
	100% { margin-left: 70%; width: 30%; }
}
.a1tools-progress-text {
	display: block;
	margin-top: 6px;
	font-size: 13px;
	color: #555;
}
/* Status messages */
.a1tools-status-msg.a1tools-success { color: #00a32a; }
.a1tools-status-msg.a1tools-error   { color: #d63638; }
/* Import results */
#a1tools-import-results {
	margin-top: 20px;
}
#a1tools-import-results .widefat {
	max-width: 800px;
}
';
	}

	// =========================================================================
	// Inline JavaScript
	// =========================================================================

	/**
	 * Return admin JS for the Import/Export page.
	 *
	 * @return string JavaScript string.
	 */
	private function get_admin_js() {
		return <<<'JS'
(function($) {
	'use strict';

	var s = a1toolsIE;

	/* ── Helper: build page list HTML from AJAX data ─────────── */
	function buildPageListHtml(pages) {
		if (!pages || pages.length === 0) {
			return '<p class="description">No pages found for this author.</p>';
		}
		var html = '<div class="a1tools-page-checkboxes">';
		$.each(pages, function(i, p) {
			var badge = p.has_elementor
				? ' <span class="a1tools-elementor-badge">Elementor</span>'
				: '';
			var sBadge = p.status !== 'publish'
				? ' <span class="a1tools-status-badge a1tools-status-' + p.status + '">' + p.status + '</span>'
				: '';
			html += '<label class="a1tools-page-item">';
			html += '<input type="checkbox" name="a1tools_page_ids[]" value="' + p.id + '" />';
			html += ' ' + $('<span/>').text(p.title || '(no title)').html();
			html += badge + sBadge;
			html += '</label>';
		});
		html += '</div>';
		return html;
	}

	/* ── Author filter change → AJAX reload ──────────────────── */
	$('#a1tools-export-author').on('change', function() {
		var authorId = $(this).val() || 0;

		// Show spinner, hide current list.
		$('#a1tools-page-list').hide();
		$('#a1tools-page-list-spinner').show();
		$('#a1tools-page-list-controls').hide();

		$.post(s.ajaxUrl, {
			action: 'a1tools_get_pages_by_author',
			nonce: s.noncePages,
			author_id: authorId
		}, function(res) {
			$('#a1tools-page-list-spinner').hide();

			if (res.success && res.data.pages.length > 0) {
				$('#a1tools-page-list').html(buildPageListHtml(res.data.pages)).show();
				$('#a1tools-page-list-controls').show();
				$('#a1tools-page-count').text(res.data.pages.length + (res.data.pages.length === 1 ? ' page' : ' pages'));
			} else {
				$('#a1tools-page-list').html('<p class="description">No pages found for this author.</p>').show();
				$('#a1tools-page-list-controls').hide();
			}
		}).fail(function() {
			$('#a1tools-page-list-spinner').hide();
			$('#a1tools-page-list').html('<p style="color:#d63638;">Failed to load pages. Please refresh and try again.</p>').show();
		});
	});

	/* ── Select / Deselect All ───────────────────────────────── */
	$('#a1tools-select-all').on('click', function() {
		$('#a1tools-page-list input[type="checkbox"]').prop('checked', true);
	});
	$('#a1tools-deselect-all').on('click', function() {
		$('#a1tools-page-list input[type="checkbox"]').prop('checked', false);
	});

	/* ── Export ───────────────────────────────────────────────── */
	$('#a1tools-export-btn').on('click', function() {
		var ids = [];
		$('#a1tools-page-list input[type="checkbox"]:checked').each(function() {
			ids.push($(this).val());
		});
		if (ids.length === 0) {
			alert('Please select at least one page to export.');
			return;
		}

		var $btn = $(this),
		    $st  = $('#a1tools-export-status'),
		    $prog = $('#a1tools-export-progress'),
		    $fill = $('#a1tools-export-progress-fill'),
		    $text = $('#a1tools-export-progress-text');

		$btn.prop('disabled', true);
		$st.text('').removeClass('a1tools-success a1tools-error');
		$fill.css('width', '0%').addClass('a1tools-indeterminate');
		$text.text('Preparing export for ' + ids.length + (ids.length === 1 ? ' page' : ' pages') + '...');
		$prog.show();

		$.post(s.ajaxUrl, {
			action: 'a1tools_export_pages',
			nonce: s.nonceExport,
			page_ids: ids,
			format: $('#a1tools-export-format').val()
		}, function(res) {
			$btn.prop('disabled', false);
			$fill.removeClass('a1tools-indeterminate');

			if (res.success) {
				$fill.css('width', '100%');
				$text.text('Download starting...');

				var blob = new Blob([res.data.content], { type: res.data.mime });
				var url  = URL.createObjectURL(blob);
				var a    = document.createElement('a');
				a.href     = url;
				a.download = res.data.filename;
				document.body.appendChild(a);
				a.click();
				document.body.removeChild(a);
				URL.revokeObjectURL(url);

				$text.text('Exported ' + ids.length + (ids.length === 1 ? ' page' : ' pages') + ' successfully!');
				$st.text('').addClass('a1tools-success');
				setTimeout(function() { $prog.fadeOut(); }, 4000);
			} else {
				$fill.css('width', '100%').css('background', '#d63638');
				$text.text(res.data.message || 'Export failed.');
				$st.text('').addClass('a1tools-error');
				setTimeout(function() {
					$prog.fadeOut(function() { $fill.css('background', ''); });
				}, 5000);
			}
		}).fail(function() {
			$btn.prop('disabled', false);
			$fill.removeClass('a1tools-indeterminate').css('width', '100%').css('background', '#d63638');
			$text.text('Export failed. Please try again.');
			setTimeout(function() {
				$prog.fadeOut(function() { $fill.css('background', ''); });
			}, 5000);
		});
	});

	/* ── Import ───────────────────────────────────────────────── */
	$('#a1tools-import-btn').on('click', function() {
		var fileInput = $('#a1tools-import-file')[0];
		if (!fileInput.files || !fileInput.files[0]) {
			alert('Please select a file to import.');
			return;
		}

		var $btn  = $(this),
		    $st   = $('#a1tools-import-status'),
		    $prog = $('#a1tools-import-progress'),
		    $fill = $('#a1tools-import-progress-fill'),
		    $text = $('#a1tools-import-progress-text');

		$btn.prop('disabled', true);
		$st.text('').removeClass('a1tools-success a1tools-error');
		$('#a1tools-import-results').hide();
		$fill.css('width', '0%').css('background', '').addClass('a1tools-indeterminate');
		$text.text('Uploading and importing pages...');
		$prog.show();

		var fd = new FormData();
		fd.append('action', 'a1tools_import_pages');
		fd.append('nonce', s.nonceImport);
		fd.append('import_file', fileInput.files[0]);
		fd.append('duplicate_handling', $('#a1tools-duplicate-handling').val());
		fd.append('author_id', $('#a1tools-import-author').val());
		fd.append('parent_page_id', $('#a1tools-import-parent').val() || '0');

		$.ajax({
			url: s.ajaxUrl,
			type: 'POST',
			data: fd,
			processData: false,
			contentType: false,
			success: function(res) {
				$btn.prop('disabled', false);
				$fill.removeClass('a1tools-indeterminate');

				if (res.success) {
					var d = res.data;
					var total = d.imported + d.updated + d.skipped + d.errors;

					$fill.css('width', '100%');
					$text.text('Processed ' + total + (total === 1 ? ' page' : ' pages') + ' successfully!');

					var summary = '<p>';
					summary += '<strong>Imported:</strong> ' + d.imported + ' &nbsp;|&nbsp; ';
					summary += '<strong>Updated:</strong> '  + d.updated  + ' &nbsp;|&nbsp; ';
					summary += '<strong>Skipped:</strong> '  + d.skipped  + ' &nbsp;|&nbsp; ';
					summary += '<strong>Errors:</strong> '   + d.errors;
					summary += '</p>';
					$('#a1tools-import-summary').html(summary);

					var tbl = '<table class="widefat"><thead><tr><th>Page</th><th>Action</th><th>Details</th></tr></thead><tbody>';
					$.each(d.details, function(i, r) {
						var cls = r.action === 'error' ? ' style="color:#d63638;"' : '';
						tbl += '<tr' + cls + '>';
						tbl += '<td>' + $('<span/>').text(r.title).html() + '</td>';
						tbl += '<td>' + r.action + '</td>';
						tbl += '<td>' + $('<span/>').text(r.message).html() + '</td>';
						tbl += '</tr>';
					});
					tbl += '</tbody></table>';
					$('#a1tools-import-details').html(tbl);
					$('#a1tools-import-results').show();
					setTimeout(function() { $prog.fadeOut(); }, 3000);
				} else {
					$fill.css('width', '100%').css('background', '#d63638');
					$text.text(res.data.message || 'Import failed.');
					setTimeout(function() {
						$prog.fadeOut(function() { $fill.css('background', ''); });
					}, 5000);
				}
			},
			error: function() {
				$btn.prop('disabled', false);
				$fill.removeClass('a1tools-indeterminate').css('width', '100%').css('background', '#d63638');
				$text.text('Import failed. Please try again.');
				setTimeout(function() {
					$prog.fadeOut(function() { $fill.css('background', ''); });
				}, 5000);
			}
		});
	});

})(jQuery);
JS;
	}
}