<?php
// If this file is called directly, abort.
if ( ! defined( 'WPINC' ) ) {
	die;
}

/**
 * AIO Tools Standalone 3-Tier Full-Page Cache & Preloader Engine
 * Tier 1: .htaccess Direct Disk Rewrite (0ms PHP)
 * Tier 2: wp-content/advanced-cache.php Drop-in (~10-20ms, zero DB)
 * Tier 3: Fallback plugins_loaded + Output Buffer Writer (.html + .html.gz) + Sitemap Preloader
 */
class AIO_Caching {

	private $options;
	private $cache_dir;
	private $is_caching_active;

	public function __construct( $register_hooks = true ) {
		$this->options = get_option( 'aio_options', [] );

		$upload_dir      = wp_upload_dir();
		$this->cache_dir = trailingslashit( wp_normalize_path( $upload_dir['basedir'] ) ) . 'aio-cache/';

		if ( ! $register_hooks ) {
			return;
		}

		$maintenance_enabled     = ! empty( $this->options['optEnableMaintenance'] );
		$this->is_caching_active = ! empty( $this->options['optEnablePageCache'] ) && ! $maintenance_enabled && ! aio_is_speed_safe_mode();

		if ( $this->is_caching_active ) {
			add_action( 'plugins_loaded', [ $this, 'serve_cache' ], 0 );
			add_action( 'template_redirect', [ $this, 'start_buffer' ], -9999 );

			add_action( 'save_post', [ $this, 'purge_on_post_change' ], 20, 2 );
			add_action( 'deleted_post', [ $this, 'clear_all_cache' ] );
			add_action( 'switch_theme', [ $this, 'clear_all_cache' ] );
			add_action( 'wp_update_nav_menu', [ $this, 'clear_all_cache' ] );
			add_action( 'woocommerce_new_order', [ $this, 'clear_all_cache' ] );
			add_action( 'comment_post', [ $this, 'purge_on_comment' ], 20, 2 );

			add_action( 'init', [ $this, 'maybe_schedule_gc_cron' ] );
		}

		add_action( 'aio_page_cache_gc_cron', [ $this, 'cleanup_expired_cache' ] );
		add_action( 'aio_cache_preload_batch', [ $this, 'process_preload_batch' ] );
		add_action( 'aio_tools_settings_updated', [ $this, 'on_settings_updated' ], 10, 1 );
		add_action( 'wp_head', [ $this, 'output_preload_tags' ], 1 );

		// AJAX endpoints
		add_action( 'wp_ajax_aio_clear_page_cache', [ $this, 'ajax_clear_cache' ] );
		add_action( 'wp_ajax_aio_get_page_cache_stats', [ $this, 'ajax_get_cache_stats' ] );
		add_action( 'wp_ajax_aio_start_cache_preload', [ $this, 'ajax_start_preload' ] );
		add_action( 'wp_ajax_aio_reinstall_adv_cache', [ $this, 'ajax_reinstall_adv_cache' ] );
	}

	/**
	 * Detect any other active page cache plugins so UI can alert admin without disabling AIO Tools.
	 */
	public static function detect_competing_cache_plugins() {
		$found = [];
		if ( defined( 'WP_ROCKET_VERSION' ) ) {
			$found[] = 'WP Rocket';
		}
		if ( defined( 'LSCACHE_V' ) || class_exists( 'LiteSpeed_Cache' ) ) {
			$found[] = 'LiteSpeed Cache';
		}
		if ( defined( 'W3TC' ) ) {
			$found[] = 'W3 Total Cache';
		}
		if ( function_exists( 'wp_cache_phase2' ) || defined( 'WPCACHEHOME' ) ) {
			$found[] = 'WP Super Cache';
		}
		if ( class_exists( 'WpFastestCache' ) ) {
			$found[] = 'WP Fastest Cache';
		}
		if ( defined( 'AUTOPTIMIZE_PLUGIN_VERSION' ) ) {
			$found[] = 'Autoptimize';
		}
		return $found;
	}

	private function is_excluded_cookie_present() {
		if ( empty( $_COOKIE ) ) {
			return false;
		}
		$prefixes = [
			'wordpress_logged_in_',
			'wp-postpass_',
			'woocommerce_items_in_cart',
			'wp_woocommerce_session_',
			'aio_maint_bypass',
			'comment_author_',
		];
		if ( ! empty( $this->options['optCacheExcludeCookies'] ) ) {
			foreach ( preg_split( '/[\r\n]+/', (string) $this->options['optCacheExcludeCookies'] ) as $c ) {
				$c = trim( $c );
				if ( $c !== '' ) {
					$prefixes[] = $c;
				}
			}
		}
		foreach ( array_keys( $_COOKIE ) as $key ) {
			foreach ( $prefixes as $pref ) {
				if ( $pref !== '' && stripos( (string) $key, $pref ) !== false ) {
					return true;
				}
			}
		}
		return false;
	}

	private function has_disallowed_query_args() {
		// phpcs:ignore WordPress.Security.NonceVerification.Recommended
		if ( empty( $_GET ) ) {
			return false;
		}
		$ignore_tracking = ! isset( $this->options['optCacheIgnoreTracking'] ) || ! empty( $this->options['optCacheIgnoreTracking'] );
		if ( ! $ignore_tracking ) {
			return true;
		}
		$ignored = [
			'utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content', 'utm_id',
			'fbclid', 'gclid', 'dclid', 'msclkid', 'ttclid', 'twclid', 'yclid', 'zarsrc',
			'_ga', '_gl', 'mc_cid', 'mc_eid',
		];
		// phpcs:ignore WordPress.Security.NonceVerification.Recommended
		foreach ( array_keys( $_GET ) as $qkey ) {
			if ( ! in_array( strtolower( (string) $qkey ), $ignored, true ) ) {
				return true;
			}
		}
		return false;
	}

	private function is_mobile_visitor() {
		if ( empty( $this->options['optCacheSeparateMobile'] ) ) {
			return false;
		}
		$ua = isset( $_SERVER['HTTP_USER_AGENT'] ) ? (string) wp_unslash( $_SERVER['HTTP_USER_AGENT'] ) : '';
		return (bool) preg_match( '/Mobile|Android|Silk\/|Kindle|BlackBerry|Opera (?:Mini|Mobi)|iPhone|iPod/i', $ua );
	}

	/**
	 * Safely build cache file path while preventing Host Header Poisoning and Path Traversal.
	 */
	private function get_cache_filepath( $custom_url = '' ) {
		$expected_host = strtolower( (string) wp_parse_url( home_url(), PHP_URL_HOST ) );
		if ( empty( $expected_host ) ) {
			return false;
		}

		if ( $custom_url !== '' ) {
			$uri_path = (string) wp_parse_url( $custom_url, PHP_URL_PATH );
			$scheme   = strtolower( (string) wp_parse_url( $custom_url, PHP_URL_SCHEME ) );
			$is_https = ( $scheme === 'https' );
		} else {
			$raw_host = isset( $_SERVER['HTTP_HOST'] ) ? strtolower( sanitize_text_field( wp_unslash( $_SERVER['HTTP_HOST'] ) ) ) : '';
			$req_host = preg_replace( '/:\d+$/', '', $raw_host );
			if ( $req_host !== $expected_host ) {
				return false;
			}
			$raw_uri = isset( $_SERVER['REQUEST_URI'] ) ? (string) wp_unslash( $_SERVER['REQUEST_URI'] ) : '/';
			if ( strpos( $raw_uri, "\0" ) !== false || strpos( $raw_uri, '\\' ) !== false || strpos( $raw_uri, '..' ) !== false ) {
				return false;
			}
			$uri_path = (string) wp_parse_url( $raw_uri, PHP_URL_PATH );
			$is_https = is_ssl();
		}

		if ( preg_match( '/\.(?:xml|txt|json|php|ico|css|js)$/i', $uri_path ) ) {
			return false;
		}

		if ( ! empty( $this->options['optCacheExcludeUrls'] ) ) {
			foreach ( preg_split( '/[\r\n]+/', (string) $this->options['optCacheExcludeUrls'] ) as $ex ) {
				$ex = trim( $ex );
				if ( $ex !== '' && stripos( $uri_path, $ex ) !== false ) {
					return false;
				}
			}
		}

		$segments      = array_filter( explode( '/', trim( $uri_path, '/' ) ), 'strlen' );
		$safe_segments = [];
		foreach ( $segments as $seg ) {
			$clean = preg_replace( '/[^A-Za-z0-9._~%-]/', '_', $seg );
			if ( $clean === '' || $clean === '.' || $clean === '..' ) {
				return false;
			}
			$safe_segments[] = substr( $clean, 0, 120 );
		}

		$scheme_prefix = $is_https ? 'https-' : 'http-';
		$sub_path      = ! empty( $safe_segments ) ? implode( '/', $safe_segments ) . '/' : '';
		$file_name     = ( $custom_url === '' && $this->is_mobile_visitor() ) ? 'index-mobile.html' : 'index.html';
		$full_path     = wp_normalize_path( $this->cache_dir . $scheme_prefix . $expected_host . '/' . $sub_path . $file_name );

		if ( strpos( $full_path, $this->cache_dir ) !== 0 ) {
			return false;
		}

		return $full_path;
	}

	private function get_ttl_seconds() {
		$hours = isset( $this->options['optCacheTtlHours'] ) ? absint( $this->options['optCacheTtlHours'] ) : 24;
		return $hours > 0 ? ( $hours * HOUR_IN_SECONDS ) : 0;
	}

	public function serve_cache() {
		if ( ! isset( $_SERVER['REQUEST_METHOD'] ) || $_SERVER['REQUEST_METHOD'] !== 'GET' ) {
			return;
		}
		if ( aio_is_speed_safe_mode() || $this->has_disallowed_query_args() || $this->is_excluded_cookie_present() ) {
			return;
		}

		$cache_file = $this->get_cache_filepath();
		if ( ! $cache_file || ! file_exists( $cache_file ) ) {
			return;
		}

		$ttl = $this->get_ttl_seconds();
		if ( $ttl > 0 && ( time() - filemtime( $cache_file ) ) > $ttl ) {
			@unlink( $cache_file ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
			if ( file_exists( $cache_file . '.gz' ) ) {
				@unlink( $cache_file . '.gz' ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
			}
			return;
		}

		$accept_enc = isset( $_SERVER['HTTP_ACCEPT_ENCODING'] ) ? strtolower( (string) wp_unslash( $_SERVER['HTTP_ACCEPT_ENCODING'] ) ) : '';
		$gz_file    = $cache_file . '.gz';
		$can_gzip   = ( strpos( $accept_enc, 'gzip' ) !== false ) && ! ini_get( 'zlib.output_compression' ) && file_exists( $gz_file );

		header( 'Content-Type: text/html; charset=UTF-8' );
		header( 'Vary: Accept-Encoding' );

		if ( $can_gzip ) {
			header( 'Content-Encoding: gzip' );
			header( 'Content-Length: ' . filesize( $gz_file ) );
			header( 'X-AIO-Cache: HIT-GZIP' );
			readfile( $gz_file );
			exit;
		}

		header( 'X-AIO-Cache: HIT' );
		readfile( $cache_file );
		exit;
	}

	public function start_buffer() {
		if ( ! isset( $_SERVER['REQUEST_METHOD'] ) || $_SERVER['REQUEST_METHOD'] !== 'GET' ) {
			return;
		}
		if ( aio_is_speed_safe_mode() || $this->has_disallowed_query_args() || is_user_logged_in() ) {
			return;
		}
		if ( defined( 'DONOTCACHEPAGE' ) && DONOTCACHEPAGE ) {
			return;
		}
		if ( is_404() || is_search() || is_feed() || is_trackback() || is_preview() ) {
			return;
		}
		if ( function_exists( 'is_cart' ) && ( is_cart() || is_checkout() || is_account_page() ) ) {
			return;
		}
		if ( $this->is_excluded_cookie_present() ) {
			return;
		}

		ob_start( [ $this, 'cache_callback' ] );
	}

	public function cache_callback( $buffer ) {
		if ( empty( $buffer ) || strlen( $buffer ) < 255 ) {
			return $buffer;
		}
		if ( http_response_code() !== 200 || stripos( $buffer, '</html>' ) === false ) {
			return $buffer;
		}
		if ( defined( 'DONOTCACHEPAGE' ) && DONOTCACHEPAGE ) {
			return $buffer;
		}

		$cache_file = $this->get_cache_filepath();
		if ( ! $cache_file ) {
			return $buffer;
		}

		if ( ! file_exists( $this->cache_dir ) ) {
			wp_mkdir_p( $this->cache_dir );
		}
		if ( ! file_exists( $this->cache_dir . 'index.php' ) ) {
			if ( class_exists( 'AIO_Dropin_Manager' ) ) {
				AIO_Dropin_Manager::write_runtime_config( $this->options );
			} else {
				@file_put_contents( $this->cache_dir . 'index.php', "<?php\n// Silence is golden.\n" ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
			}
		}

		$dir = dirname( $cache_file );
		if ( ! file_exists( $dir ) ) {
			wp_mkdir_p( $dir );
		}

		$signature = "\n<!-- Cached by AIO Tools Turbo Engine on " . current_time( 'mysql' ) . ' -->';
		$payload   = $buffer . $signature;
		@file_put_contents( $cache_file, $payload ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged

		if ( function_exists( 'gzencode' ) ) {
			$gz_payload = @gzencode( $payload, 6 ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
			if ( $gz_payload !== false ) {
				@file_put_contents( $cache_file . '.gz', $gz_payload ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
			}
		}

		if ( ! headers_sent() ) {
			header( 'X-AIO-Cache: MISS' );
		}
		return $buffer;
	}

	/**
	 * Granular cache invalidation when a post/page/product is updated.
	 */
	public function purge_on_post_change( $post_id, $post = null ) {
		if ( wp_is_post_revision( $post_id ) || wp_is_post_autosave( $post_id ) ) {
			return;
		}
		if ( is_object( $post ) && ! in_array( $post->post_status, [ 'publish', 'trash', 'private' ], true ) ) {
			return;
		}

		$urls_to_purge = [ home_url( '/' ) ];
		$permalink     = get_permalink( $post_id );
		if ( $permalink ) {
			$urls_to_purge[] = $permalink;
		}
		$posts_page = get_option( 'page_for_posts' );
		if ( $posts_page ) {
			$urls_to_purge[] = get_permalink( $posts_page );
		}
		if ( function_exists( 'wc_get_page_permalink' ) ) {
			$shop_url = wc_get_page_permalink( 'shop' );
			if ( $shop_url ) {
				$urls_to_purge[] = $shop_url;
			}
		}

		$taxonomies = get_object_taxonomies( get_post_type( $post_id ) );
		if ( is_array( $taxonomies ) ) {
			foreach ( $taxonomies as $tax ) {
				$terms = get_the_terms( $post_id, $tax );
				if ( is_array( $terms ) ) {
					foreach ( array_slice( $terms, 0, 10 ) as $term ) {
						$tlink = get_term_link( $term );
						if ( ! is_wp_error( $tlink ) ) {
							$urls_to_purge[] = $tlink;
						}
					}
				}
			}
		}

		foreach ( array_unique( $urls_to_purge ) as $u ) {
			$this->purge_single_url( $u );
		}
	}

	public function purge_on_comment( $comment_id, $comment_approved ) {
		if ( $comment_approved === 1 || $comment_approved === '1' ) {
			$comment = get_comment( $comment_id );
			if ( $comment && ! empty( $comment->comment_post_ID ) ) {
				$this->purge_single_url( get_permalink( (int) $comment->comment_post_ID ) );
			}
		}
	}

	public function maybe_schedule_gc_cron() {
		if ( ! wp_next_scheduled( 'aio_page_cache_gc_cron' ) ) {
			wp_schedule_event( time() + HOUR_IN_SECONDS, 'hourly', 'aio_page_cache_gc_cron' );
		}
	}

	public static function purge_single_url_static( $url ) {
		$inst = new self( false );
		$inst->purge_single_url( $url );
	}

	public function purge_single_url( $url ) {
		if ( empty( $url ) ) {
			return;
		}
		$file = $this->get_cache_filepath( $url );
		if ( ! $file ) {
			return;
		}
		$dir = dirname( $file );
		foreach ( [ 'index.html', 'index.html.gz', 'index-mobile.html', 'index-mobile.html.gz' ] as $fn ) {
			$target = $dir . '/' . $fn;
			if ( is_file( $target ) ) {
				@unlink( $target ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
			}
		}
	}

	public function on_settings_updated( $new_options = [] ) {
		if ( is_array( $new_options ) ) {
			$this->options = $new_options;
		}
		$this->clear_all_cache();
		if ( ! empty( $this->options['optEnablePageCache'] ) && ! empty( $this->options['optEnableCachePreload'] ) ) {
			$this->schedule_cache_preload();
		}
	}

	public function clear_all_cache() {
		if ( file_exists( $this->cache_dir ) ) {
			$this->delete_cached_html_only( $this->cache_dir );
		}
	}

	/**
	 * Static helper to purge all cached HTML files without re-registering hooks.
	 */
	public static function purge_all_static() {
		$upload_dir = wp_upload_dir();
		$cache_dir  = trailingslashit( wp_normalize_path( $upload_dir['basedir'] ) ) . 'aio-cache/';
		if ( ! is_dir( $cache_dir ) ) {
			return;
		}
		$files = glob( $cache_dir . '*', GLOB_MARK );
		if ( ! is_array( $files ) ) {
			return;
		}
		foreach ( $files as $file ) {
			if ( is_dir( $file ) ) {
				self::remove_dir_static( $file );
			} else {
				$base = basename( $file );
				if ( ! in_array( $base, [ 'index.php', '.htaccess', 'cache-config.php', 'object-cache-config.php' ], true ) ) {
					@unlink( $file ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
				}
			}
		}
	}

	private static function remove_dir_static( $dir_path ) {
		if ( ! is_dir( $dir_path ) ) {
			return;
		}
		$dir_path = trailingslashit( $dir_path );
		$files    = glob( $dir_path . '*', GLOB_MARK );
		if ( is_array( $files ) ) {
			foreach ( $files as $file ) {
				if ( is_dir( $file ) ) {
					self::remove_dir_static( $file );
				} else {
					@unlink( $file ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
				}
			}
		}
		@rmdir( $dir_path ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
	}

	/**
	 * Delete cached HTML subdirectories while preserving cache-config.php & object-cache-config.php.
	 */
	private function delete_cached_html_only( $dir_path ) {
		if ( ! is_dir( $dir_path ) ) {
			return;
		}
		$dir_path = trailingslashit( $dir_path );
		$files    = glob( $dir_path . '*', GLOB_MARK );
		if ( is_array( $files ) ) {
			foreach ( $files as $file ) {
				if ( is_dir( $file ) ) {
					$this->delete_dir_recursive( $file );
				} else {
					$base = basename( $file );
					if ( ! in_array( $base, [ 'index.php', '.htaccess', 'cache-config.php', 'object-cache-config.php' ], true ) ) {
						@unlink( $file ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
					}
				}
			}
		}
	}

	/**
	 * Hourly WP-Cron Garbage Collector: removes expired .html / .html.gz files on disk
	 * so Tier 1 .htaccess Zero-PHP rewrite never serves stale cached pages past TTL.
	 */
	public function cleanup_expired_cache() {
		$ttl = $this->get_ttl_seconds();
		if ( $ttl <= 0 || ! is_dir( $this->cache_dir ) ) {
			return;
		}
		$now = time();
		$this->gc_walk_dir( $this->cache_dir, $ttl, $now, true );
	}

	private function gc_walk_dir( $dir_path, $ttl, $now, $is_root = false ) {
		if ( ! is_dir( $dir_path ) ) {
			return;
		}
		$dir_path = trailingslashit( $dir_path );
		$items    = glob( $dir_path . '*', GLOB_MARK );
		if ( is_array( $items ) ) {
			foreach ( $items as $item ) {
				if ( is_dir( $item ) ) {
					$this->gc_walk_dir( $item, $ttl, $now, false );
				} else {
					$base = basename( $item );
					if ( substr( $base, -5 ) === '.html' || substr( $base, -8 ) === '.html.gz' ) {
						$mtime = (int) @filemtime( $item ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
						if ( $mtime > 0 && ( $now - $mtime ) > $ttl ) {
							@unlink( $item ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
						}
					}
				}
			}
		}
		if ( ! $is_root ) {
			$remaining = glob( $dir_path . '*' );
			if ( is_array( $remaining ) && empty( $remaining ) ) {
				@rmdir( $dir_path ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
			}
		}
	}

	private function delete_dir_recursive( $dir_path ) {
		if ( ! is_dir( $dir_path ) ) {
			return;
		}
		$dir_path = trailingslashit( $dir_path );
		$files    = glob( $dir_path . '*', GLOB_MARK );
		if ( is_array( $files ) ) {
			foreach ( $files as $file ) {
				if ( is_dir( $file ) ) {
					$this->delete_dir_recursive( $file );
				} else {
					@unlink( $file ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
				}
			}
		}
		@rmdir( $dir_path ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
	}

	/**
	 * Compute live statistics (number of cached HTML pages & total bytes on disk).
	 */
	public function get_disk_stats() {
		$pages = 0;
		$bytes = 0;
		if ( is_dir( $this->cache_dir ) ) {
			$iterator = new RecursiveIteratorIterator(
				new RecursiveDirectoryIterator( $this->cache_dir, FilesystemIterator::SKIP_DOTS )
			);
			foreach ( $iterator as $file_info ) {
				if ( $file_info->isFile() ) {
					$name = $file_info->getFilename();
					if ( substr( $name, -5 ) === '.html' ) {
						$pages++;
					}
					if ( substr( $name, -5 ) === '.html' || substr( $name, -8 ) === '.html.gz' ) {
						$bytes += (int) $file_info->getSize();
					}
				}
			}
		}

		$preload_state = get_option( 'aio_cache_preload_state', [] );

		return [
			'pages'         => $pages,
			'bytes'         => $bytes,
			'size_human'    => size_format( $bytes, 1 ),
			'preloading'    => ! empty( $preload_state['running'] ),
			'preload_done'  => isset( $preload_state['done'] ) ? (int) $preload_state['done'] : 0,
			'preload_total' => isset( $preload_state['total'] ) ? (int) $preload_state['total'] : 0,
		];
	}

	/**
	 * Build queue of top public URLs (Homepage + recent Pages, Posts, Products, Categories) and schedule preloader.
	 */
	public function schedule_cache_preload() {
		$urls = [ home_url( '/' ) ];

		$post_types = [ 'page', 'post' ];
		if ( post_type_exists( 'product' ) ) {
			$post_types[] = 'product';
		}

		$q = new WP_Query( [
			'post_type'              => $post_types,
			'post_status'            => 'publish',
			'posts_per_page'         => 45,
			'orderby'                => 'modified',
			'order'                  => 'DESC',
			'fields'                 => 'ids',
			'no_found_rows'          => true,
			'update_post_meta_cache' => false,
			'update_post_term_cache' => false,
		] );

		if ( ! empty( $q->posts ) ) {
			foreach ( $q->posts as $pid ) {
				$link = get_permalink( $pid );
				if ( $link ) {
					$urls[] = $link;
				}
			}
		}

		$cats = get_terms( [
			'taxonomy'   => 'category',
			'hide_empty' => true,
			'number'     => 10,
		] );
		if ( is_array( $cats ) ) {
			foreach ( $cats as $c ) {
				$clink = get_term_link( $c );
				if ( ! is_wp_error( $clink ) ) {
					$urls[] = $clink;
				}
			}
		}

		$urls = array_values( array_unique( array_filter( $urls ) ) );

		$state = [
			'running' => true,
			'queue'   => $urls,
			'done'    => 0,
			'total'   => count( $urls ),
		];
		update_option( 'aio_cache_preload_state', $state, false );

		if ( ! wp_next_scheduled( 'aio_cache_preload_batch' ) ) {
			wp_schedule_single_event( time() + 1, 'aio_cache_preload_batch' );
		}

		return $state;
	}

	/**
	 * Background batch warmer: visits up to 8 URLs per batch anonymously to build .html + .html.gz files.
	 */
	public function process_preload_batch() {
		$state = get_option( 'aio_cache_preload_state', [] );
		if ( empty( $state['running'] ) || empty( $state['queue'] ) || ! is_array( $state['queue'] ) ) {
			$state['running'] = false;
			update_option( 'aio_cache_preload_state', $state, false );
			return;
		}

		$batch = array_splice( $state['queue'], 0, 8 );
		foreach ( $batch as $url ) {
			wp_remote_get(
				$url,
				[
					'timeout'     => 6,
					'redirection' => 2,
					'sslverify'   => false,
					'cookies'     => [],
					'headers'     => [
						'Accept-Encoding' => 'gzip',
						'User-Agent'      => 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) Chrome/122.0.0.0 AIO-Cache-Preloader/3.0.9',
					],
				]
			);
			$state['done'] = isset( $state['done'] ) ? ( (int) $state['done'] + 1 ) : 1;
		}

		if ( empty( $state['queue'] ) ) {
			$state['running'] = false;
		} else {
			wp_schedule_single_event( time() + 3, 'aio_cache_preload_batch' );
		}

		update_option( 'aio_cache_preload_state', $state, false );
	}

	public function ajax_clear_cache() {
		check_ajax_referer( 'aio-settings-nonce', 'security' );
		if ( ! current_user_can( 'manage_options' ) ) {
			wp_send_json_error( __( 'Unauthorized', 'aio-tools' ) );
		}

		$this->clear_all_cache();
		delete_transient( 'aio_img_dims_cache' );
		if ( class_exists( 'AIO_Asset_Optimizer' ) ) {
			AIO_Asset_Optimizer::clear_minified_assets();
		}

		wp_send_json_success(
			[
				'message' => __( 'Page cache and minified assets cleared successfully!', 'aio-tools' ),
				'stats'   => $this->get_disk_stats(),
			]
		);
	}

	public function ajax_get_cache_stats() {
		check_ajax_referer( 'aio-settings-nonce', 'security' );
		if ( ! current_user_can( 'manage_options' ) ) {
			wp_send_json_error( __( 'Unauthorized', 'aio-tools' ) );
		}
		wp_send_json_success( $this->get_disk_stats() );
	}

	public function ajax_start_preload() {
		check_ajax_referer( 'aio-settings-nonce', 'security' );
		if ( ! current_user_can( 'manage_options' ) ) {
			wp_send_json_error( __( 'Unauthorized', 'aio-tools' ) );
		}

		$state = $this->schedule_cache_preload();
		// Process first batch immediately so homepage & top pages are warm right away!
		$this->process_preload_batch();

		wp_send_json_success(
			[
				'message' => __( 'Cache preloader started! Homepage and top pages are now warm.', 'aio-tools' ),
				'stats'   => $this->get_disk_stats(),
			]
		);
	}

	public function ajax_reinstall_adv_cache() {
		check_ajax_referer( 'aio-settings-nonce', 'security' );
		if ( ! current_user_can( 'manage_options' ) ) {
			wp_send_json_error( __( 'Unauthorized', 'aio-tools' ) );
		}

		if ( ! class_exists( 'AIO_Dropin_Manager' ) ) {
			require_once AIO_MODULES_PATH . 'performance/class-aio-dropin-manager.php';
		}

		$ok = AIO_Dropin_Manager::sync_advanced_cache( true, true, $this->options );
		if ( $ok ) {
			wp_send_json_success( __( 'Installed advanced-cache.php Drop-in & enabled WP_CACHE successfully!', 'aio-tools' ) );
		} else {
			wp_send_json_error( __( 'Could not write wp-content/advanced-cache.php. Please check directory permissions.', 'aio-tools' ) );
		}
	}

	public function output_preload_tags() {
		if ( aio_is_speed_safe_mode() ) {
			return;
		}

		if ( ! empty( $this->options['optPrefetchDomains'] ) ) {
			$raw_items = preg_split( '/[\r\n,\s]+/', (string) $this->options['optPrefetchDomains'] );
			$seen      = [];
			foreach ( $raw_items as $domain ) {
				$domain = trim( $domain );
				if ( empty( $domain ) ) {
					continue;
				}
				if ( strpos( $domain, '//' ) === 0 ) {
					$domain = 'https:' . $domain;
				} elseif ( ! preg_match( '#^https?://#i', $domain ) ) {
					$domain = 'https://' . ltrim( $domain, '/' );
				}
				$parsed = wp_parse_url( $domain );
				if ( empty( $parsed['host'] ) ) {
					continue;
				}
				$origin = ( ! empty( $parsed['scheme'] ) ? strtolower( $parsed['scheme'] ) : 'https' ) . '://' . strtolower( $parsed['host'] );
				if ( isset( $seen[ $origin ] ) ) {
					continue;
				}
				$seen[ $origin ] = true;
				echo '<link rel="dns-prefetch" href="' . esc_url( $origin ) . '">' . "\n";
				echo '<link rel="preconnect" href="' . esc_url( $origin ) . '" crossorigin>' . "\n";
			}
		}

		if ( ! empty( $this->options['optPreloadAssets'] ) ) {
			$assets = preg_split( '/[\r\n\s]+/', (string) $this->options['optPreloadAssets'] );
			$seen   = [];
			foreach ( $assets as $asset ) {
				$asset = trim( $asset );
				if ( empty( $asset ) || isset( $seen[ $asset ] ) ) {
					continue;
				}
				$seen[ $asset ] = true;
				$lower          = strtolower( (string) wp_parse_url( $asset, PHP_URL_PATH ) );
				if ( substr( $lower, -6 ) === '.woff2' ) {
					echo '<link rel="preload" href="' . esc_url( $asset ) . '" as="font" type="font/woff2" crossorigin>' . "\n";
				} elseif ( substr( $lower, -5 ) === '.woff' ) {
					echo '<link rel="preload" href="' . esc_url( $asset ) . '" as="font" type="font/woff" crossorigin>' . "\n";
				} elseif ( substr( $lower, -4 ) === '.ttf' ) {
					echo '<link rel="preload" href="' . esc_url( $asset ) . '" as="font" type="font/ttf" crossorigin>' . "\n";
				} elseif ( substr( $lower, -4 ) === '.css' ) {
					echo '<link rel="preload" href="' . esc_url( $asset ) . '" as="style">' . "\n";
				} elseif ( substr( $lower, -3 ) === '.js' ) {
					echo '<link rel="preload" href="' . esc_url( $asset ) . '" as="script">' . "\n";
				} elseif ( preg_match( '/\.(?:jpe?g|png|webp|avif|gif|svg)$/', $lower ) ) {
					echo '<link rel="preload" href="' . esc_url( $asset ) . '" as="image">' . "\n";
				} else {
					echo '<link rel="preload" href="' . esc_url( $asset ) . '" as="fetch" crossorigin>' . "\n";
				}
			}
		}
	}
}