<?php
// phpcs:ignoreFile

/**
 * The optimize class.
 *
 * @since       1.2.2
 */

namespace LiteSpeed;

defined('WPINC') || exit();

class Optimize extends Base {
	const LOG_TAG           = '🎢';

	const LIB_FILE_CSS_ASYNC     = 'assets/js/css_async.min.js';
	const LIB_FILE_WEBFONTLOADER = 'assets/js/webfontloader.min.js';
	const LIB_FILE_JS_DELAY      = 'assets/js/js_delay.min.js';

	const ITEM_TIMESTAMP_PURGE_CSS = 'timestamp_purge_css';

	const DUMMY_CSS_REGEX = "#<link rel=['\"]stylesheet['\"] id=['\"]litespeed-cache-dummy-css['\"] href=['\"].+assets/css/litespeed-dummy\.css[?\w.=-]*['\"][ \w='\"/]*>#isU";

	private $content;
	private $content_ori;

	private $cfg_css_min;
	private $cfg_css_comb;
	private $cfg_js_min;
	private $cfg_js_comb;
	private $cfg_css_async;
	private $cfg_js_delay_inc = array();
	private $cfg_js_defer;
	private $cfg_js_defer_exc = false;
	private $cfg_ggfonts_async;
	private $_conf_css_font_display;
	private $cfg_ggfonts_rm;

	private $dns_prefetch;
	private $dns_preconnect;
	private $_ggfonts_urls = array();
	private $_ccss;
	private $_ucss = false;

	private $__optimizer;

	private $html_foot = ''; // The html info append to <body>
	private $html_head = ''; // The html info append to <head>
	private $html_head_early = ''; // The html info prepend to top of head

	private static $_var_i    = 0;
	private $_var_preserve_js = array();
	private $_request_url;

	/**
	 * Constructor
	 *
	 * @since  4.0
	 */
	public function __construct() {
		self::debug('init');
		$this->__optimizer = $this->cls('Optimizer');
	}

	/**
	 * Init optimizer
	 *
	 * @since  3.0
	 * @access protected
	 */
	public function init() {
		$this->cfg_css_async = defined('LITESPEED_GUEST_OPTM') || $this->conf(self::O_OPTM_CSS_ASYNC);
		if ($this->cfg_css_async) {
			if (!$this->cls('Cloud')->activated()) {
				self::debug('❌ CCSS set to OFF due to QC not activated');
				$this->cfg_css_async = false;
			}
			if ((defined('LITESPEED_GUEST_OPTM') || ($this->conf(self::O_OPTM_UCSS) && $this->conf(self::O_OPTM_CSS_COMB))) && $this->conf(self::O_OPTM_UCSS_INLINE)) {
				self::debug('⚠️ CCSS set to OFF due to UCSS Inline');
				$this->cfg_css_async = false;
			}
		}
		$this->cfg_js_defer = $this->conf(self::O_OPTM_JS_DEFER);
		if (defined('LITESPEED_GUEST_OPTM')) {
			$this->cfg_js_defer = 2;
		}
		if ($this->cfg_js_defer == 2) {
			add_filter(
				'litespeed_optm_cssjs',
				function ( $con, $file_type ) {
					if ($file_type == 'js') {
						$con = str_replace('DOMContentLoaded', 'DOMContentLiteSpeedLoaded', $con);
						// $con = str_replace( 'addEventListener("load"', 'addEventListener("litespeedLoad"', $con );
					}
					return $con;
				},
				20,
				2
			);
		}

		// To remove emoji from WP
		if ($this->conf(self::O_OPTM_EMOJI_RM)) {
			$this->_emoji_rm();
		}

		if ($this->conf(self::O_OPTM_QS_RM)) {
			add_filter('style_loader_src', array( $this, 'remove_query_strings' ), 999);
			add_filter('script_loader_src', array( $this, 'remove_query_strings' ), 999);
		}

		// GM JS exclude @since 4.1
		if (defined('LITESPEED_GUEST_OPTM')) {
			$this->cfg_js_defer_exc = apply_filters('litespeed_optm_gm_js_exc', $this->conf(self::O_OPTM_GM_JS_EXC));
		} else {
			/**
			 * Exclude js from deferred setting
			 *
			 * @since 1.5
			 */
			if ($this->cfg_js_defer) {
				add_filter('litespeed_optm_js_defer_exc', array( $this->cls('Data'), 'load_js_defer_exc' ));
				$this->cfg_js_defer_exc = apply_filters('litespeed_optm_js_defer_exc', $this->conf(self::O_OPTM_JS_DEFER_EXC));

				$this->cfg_js_delay_inc = apply_filters('litespeed_optm_js_delay_inc', $this->conf(self::O_OPTM_JS_DELAY_INC));
			}
		}

		// Add vary filter for Role Excludes @since  1.6
		add_filter('litespeed_vary', array( $this, 'vary_add_role_exclude' ));

		// DNS optm (Prefetch/Preconnect) @since 7.3
		$this->_dns_optm_init();

		add_filter('litespeed_buffer_finalize', array( $this, 'finalize' ), 20);

		// Inject a dummy CSS file to control final optimized data location in <head>
		wp_enqueue_style(Core::PLUGIN_NAME . '-dummy', LSWCP_PLUGIN_URL . 'assets/css/litespeed-dummy.css');
	}

	/**
	 * Exclude role from optimization filter
	 *
	 * @since  1.6
	 * @access public
	 */
	public function vary_add_role_exclude( $vary ) {
		if ($this->cls('Conf')->in_optm_exc_roles()) {
			$vary['role_exclude_optm'] = 1;
		}

		return $vary;
	}

	/**
	 * Remove emoji from WP
	 *
	 * @since  1.4
	 * @since  2.9.8 Changed to private
	 * @access private
	 */
	private function _emoji_rm() {
		remove_action('wp_head', 'print_emoji_detection_script', 7);
		remove_action('admin_print_scripts', 'print_emoji_detection_script');
		remove_filter('the_content_feed', 'wp_staticize_emoji');
		remove_filter('comment_text_rss', 'wp_staticize_emoji');
		/**
		 * Added for better result
		 *
		 * @since  1.6.2.1
		 */
		remove_action('wp_print_styles', 'print_emoji_styles');
		remove_action('admin_print_styles', 'print_emoji_styles');
		remove_filter('wp_mail', 'wp_staticize_emoji_for_email');
	}

	/**
	 * Delete file-based cache folder
	 *
	 * @since  2.1
	 * @access public
	 */
	public function rm_cache_folder( $subsite_id = false ) {
		if ($subsite_id) {
			file_exists(LITESPEED_STATIC_DIR . '/css/' . $subsite_id) && File::rrmdir(LITESPEED_STATIC_DIR . '/css/' . $subsite_id);
			file_exists(LITESPEED_STATIC_DIR . '/js/' . $subsite_id) && File::rrmdir(LITESPEED_STATIC_DIR . '/js/' . $subsite_id);
			return;
		}

		file_exists(LITESPEED_STATIC_DIR . '/css') && File::rrmdir(LITESPEED_STATIC_DIR . '/css');
		file_exists(LITESPEED_STATIC_DIR . '/js') && File::rrmdir(LITESPEED_STATIC_DIR . '/js');
	}

	/**
	 * Remove QS
	 *
	 * @since  1.3
	 * @access public
	 */
	public function remove_query_strings( $src ) {
		if (strpos($src, '_litespeed_rm_qs=0') || strpos($src, '/recaptcha')) {
			return $src;
		}

		if (!Utility::is_internal_file($src)) {
			return $src;
		}

		if (strpos($src, '.js?') !== false || strpos($src, '.css?') !== false) {
			$src = preg_replace('/\?.*/', '', $src);
		}

		return $src;
	}

	/**
	 * Run optimize process
	 * NOTE: As this is after cache finalized, can NOT set any cache control anymore
	 *
	 * @since  1.2.2
	 * @access public
	 * @return  string The content that is after optimization
	 */
	public function finalize( $content ) {
		$content = $this->_finalize($content);
		// Fallback to replace dummy css placeholder
		if (false !== preg_match(self::DUMMY_CSS_REGEX, $content)) {
			self::debug('Fallback to drop dummy CSS');
			$content = preg_replace( self::DUMMY_CSS_REGEX, '', $content );
		}
		return $content;
	}
	private function _finalize( $content ) {
		if (defined('LITESPEED_NO_PAGEOPTM')) {
			self::debug2('bypass: NO_PAGEOPTM const');
			return $content;
		}

		if (!defined('LITESPEED_IS_HTML')) {
			self::debug('bypass: Not frontend HTML type');
			return $content;
		}

		if (!defined('LITESPEED_GUEST_OPTM')) {
			if (!Control::is_cacheable()) {
				self::debug('bypass: Not cacheable');
				return $content;
			}

			// Check if hit URI excludes
			add_filter('litespeed_optm_uri_exc', array( $this->cls('Data'), 'load_optm_uri_exc' ));
			$excludes = apply_filters('litespeed_optm_uri_exc', $this->conf(self::O_OPTM_EXC));
			$result   = Utility::str_hit_array($_SERVER['REQUEST_URI'], $excludes);
			if ($result) {
				self::debug('bypass: hit URI Excludes setting: ' . $result);
				return $content;
			}
		}

		self::debug('start');

		$this->content_ori = $this->content = $content;

		$this->_optimize();
		return $this->content;
	}

	/**
	 * Optimize css src
	 *
	 * @since  1.2.2
	 * @access private
	 */
	private function _optimize() {
		global $wp;
		$this->_request_url = get_permalink();
		// Backup, in case get_permalink() fails.
		if (!$this->_request_url) {
			$this->_request_url = home_url($wp->request);
		}

		$this->cfg_css_min            = defined('LITESPEED_GUEST_OPTM') || $this->conf(self::O_OPTM_CSS_MIN);
		$this->cfg_css_comb           = defined('LITESPEED_GUEST_OPTM') || $this->conf(self::O_OPTM_CSS_COMB);
		$this->cfg_js_min             = defined('LITESPEED_GUEST_OPTM') || $this->conf(self::O_OPTM_JS_MIN);
		$this->cfg_js_comb            = defined('LITESPEED_GUEST_OPTM') || $this->conf(self::O_OPTM_JS_COMB);
		$this->cfg_ggfonts_rm         = defined('LITESPEED_GUEST_OPTM') || $this->conf(self::O_OPTM_GGFONTS_RM);
		$this->cfg_ggfonts_async      = !defined('LITESPEED_GUEST_OPTM') && $this->conf(self::O_OPTM_GGFONTS_ASYNC); // forced rm already
		$this->_conf_css_font_display = !defined('LITESPEED_GUEST_OPTM') && $this->conf(self::O_OPTM_CSS_FONT_DISPLAY);

		if (!$this->cls('Router')->can_optm()) {
			self::debug('bypass: admin/feed/preview');
			return;
		}

		if ($this->cfg_css_async) {
			$this->_ccss = $this->cls('CSS')->prepare_ccss();
			if (!$this->_ccss) {
				self::debug('❌ CCSS set to OFF due to CCSS not generated yet');
				$this->cfg_css_async = false;
			} elseif (strpos($this->_ccss, '<style id="litespeed-ccss" data-error') === 0) {
				self::debug('❌ CCSS set to OFF due to CCSS failed to generate');
				$this->cfg_css_async = false;
			}
		}

		do_action('litespeed_optm');

		// Parse css from content
		$src_list = false;
		if ($this->cfg_css_min || $this->cfg_css_comb || $this->cfg_ggfonts_rm || $this->cfg_css_async || $this->cfg_ggfonts_async || $this->_conf_css_font_display) {
			add_filter('litespeed_optimize_css_excludes', array( $this->cls('Data'), 'load_css_exc' ));
			list($src_list, $html_list) = $this->_parse_css();
		}

		// css optimizer
		if ($this->cfg_css_min || $this->cfg_css_comb) {
			if ($src_list) {
				// IF combine
				if ($this->cfg_css_comb) {
					// Check if has inline UCSS enabled or not
					if ((defined('LITESPEED_GUEST_OPTM') || $this->conf(self::O_OPTM_UCSS)) && $this->conf(self::O_OPTM_UCSS_INLINE)) {
						$filename = $this->cls('UCSS')->load($this->_request_url, true);
						if ($filename) {
							$filepath_prefix = $this->_build_filepath_prefix('ucss');
							$this->_ucss     = File::read(LITESPEED_STATIC_DIR . $filepath_prefix . $filename);

							// Drop all css
							$this->content = str_replace($html_list, '', $this->content);
						}
					}

					if (!$this->_ucss) {
						$url = $this->_build_hash_url($src_list);

						if ($url) {
							// Handle css async load
							if ($this->cfg_css_async) {
								$this->html_head .=
									'<link rel="preload" data-asynced="1" data-optimized="2" as="style" onload="this.onload=null;this.rel=\'stylesheet\'" href="' .
									Str::trim_quotes($url) .
									'" />'; // todo: How to use " in attr wrapper "
							} else {
								$this->html_head .= '<link data-optimized="2" rel="stylesheet" href="' . Str::trim_quotes($url) . '" />'; // use 2 as combined
							}

							// Move all css to top
							$this->content = str_replace($html_list, '', $this->content);
						}
					}
				}
				// Only minify
				elseif ($this->cfg_css_min) {
					// will handle async css load inside
					$this->_src_queue_handler($src_list, $html_list);
				}
				// Only HTTP2 push
				else {
					foreach ($src_list as $src_info) {
						if (!empty($src_info['inl'])) {
							continue;
						}
					}
				}
			}
		}

		// Handle css lazy load if not handled async loaded yet
		if ($this->cfg_css_async && !$this->cfg_css_min && !$this->cfg_css_comb) {
			// async html
			$html_list_async = $this->_async_css_list($html_list, $src_list);

			// Replace async css
			$this->content = str_replace($html_list, $html_list_async, $this->content);
		}

		// Parse js from buffer as needed
		$src_list = false;
		if ($this->cfg_js_min || $this->cfg_js_comb || $this->cfg_js_defer || $this->cfg_js_delay_inc) {
			add_filter('litespeed_optimize_js_excludes', array( $this->cls('Data'), 'load_js_exc' ));
			list($src_list, $html_list) = $this->_parse_js();
		}

		// js optimizer
		if ($src_list) {
			// IF combine
			if ($this->cfg_js_comb) {
				$url = $this->_build_hash_url($src_list, 'js');
				if ($url) {
					$this->html_foot .= $this->_build_js_tag($url);

					// Will move all JS to bottom combined one
					$this->content = str_replace($html_list, '', $this->content);
				}
			}
			// Only minify
			elseif ($this->cfg_js_min) {
				// Will handle js defer inside
				$this->_src_queue_handler($src_list, $html_list, 'js');
			}
			// Only HTTP2 push and Defer
			else {
				foreach ($src_list as $k => $src_info) {
					// Inline JS
					if (!empty($src_info['inl'])) {
						if ($this->cfg_js_defer) {
							$attrs    = !empty($src_info['attrs']) ? $src_info['attrs'] : '';
							$deferred = $this->_js_inline_defer($src_info['src'], $attrs);
							if ($deferred) {
								$this->content = str_replace($html_list[$k], $deferred, $this->content);
							}
						}
					}
					// JS files
					elseif ($this->cfg_js_defer) {
						$deferred = $this->_js_defer($html_list[$k], $src_info['src']);
						if ($deferred) {
							$this->content = str_replace($html_list[$k], $deferred, $this->content);
						}
					} elseif ($this->cfg_js_delay_inc) {
						$deferred = $this->_js_delay($html_list[$k], $src_info['src']);
						if ($deferred) {
							$this->content = str_replace($html_list[$k], $deferred, $this->content);
						}
					}
				}
			}
		}

		// Append JS inline var for preserved ESI
		// Shouldn't give any optm (defer/delay) @since 4.4
		if ($this->_var_preserve_js) {
			$this->html_head .= '<script>var ' . implode(',', $this->_var_preserve_js) . ';</script>';
			self::debug2('Inline JS defer vars', $this->_var_preserve_js);
		}

		// Append async compatibility lib to head
		if ($this->cfg_css_async) {
			// Inline css async lib
			if ($this->conf(self::O_OPTM_CSS_ASYNC_INLINE)) {
				$this->html_head .= $this->_build_js_inline(File::read(LSCWP_DIR . self::LIB_FILE_CSS_ASYNC), true);
			} else {
				$css_async_lib_url = LSWCP_PLUGIN_URL . self::LIB_FILE_CSS_ASYNC;
				$this->html_head  .= $this->_build_js_tag($css_async_lib_url); // Don't exclude it from defer for now
			}
		}

		/**
		 * Handle google fonts async
		 * This will result in a JS snippet in head, so need to put it in the end to avoid being replaced by JS parser
		 */
		$this->_async_ggfonts();

		/**
		 * Font display optm
		 *
		 * @since  3.0
		 */
		$this->_font_optm();

		// Inject JS Delay lib
		$this->_maybe_js_delay();

		/**
		 * HTML Lazyload
		 */
		if ($this->conf(self::O_OPTM_HTML_LAZY)) {
			$this->html_head = $this->cls('CSS')->prepare_html_lazy() . $this->html_head;
		}

		// Maybe prepend inline UCSS
		if ($this->_ucss) {
			$this->html_head = '<style id="litespeed-ucss">' . $this->_ucss . '</style>' . $this->html_head;
		}

		// Check if there is any critical css rules setting
		if ($this->cfg_css_async && $this->_ccss) {
			$this->html_head = $this->_ccss . $this->html_head;
		}

		// Replace html head part
		$this->html_head_early = apply_filters('litespeed_optm_html_head_early', $this->html_head_early);
		if ($this->html_head_early) {
			// Put header content to be after charset
			if (false !== strpos($this->content, '<meta charset')) {
				self::debug('Put early optm data to be after <meta charset>');
				$this->content = preg_replace('#<meta charset([^>]*)>#isU', '<meta charset$1>' . $this->html_head_early, $this->content, 1);
			} else {
				self::debug('Put early optm data to be right after <head>');
				$this->content = preg_replace('#<head([^>]*)>#isU', '<head$1>' . $this->html_head_early, $this->content, 1);
			}
		}
		$this->html_head = apply_filters('litespeed_optm_html_head', $this->html_head);
		if ($this->html_head) {
			if (apply_filters('litespeed_optm_html_after_head', false)) {
				$this->content = str_replace('</head>', $this->html_head . '</head>', $this->content);
			} else {
				// Put header content to dummy css position
				if (false !== preg_match(self::DUMMY_CSS_REGEX, $this->content)) {
					self::debug('Put optm data to dummy css location');
					$this->content = preg_replace( self::DUMMY_CSS_REGEX, $this->html_head, $this->content );
				}
				// Fallback: try to be after charset
				elseif (strpos($this->content, '<meta charset') !== false) {
					self::debug('Put optm data to be after <meta charset>');
					$this->content = preg_replace('#<meta charset([^>]*)>#isU', '<meta charset$1>' . $this->html_head, $this->content, 1);
				} else {
					self::debug('Put optm data to be after <head>');
					$this->content = preg_replace('#<head([^>]*)>#isU', '<head$1>' . $this->html_head, $this->content, 1);
				}
			}
		}

		// Replace html foot part
		$this->html_foot = apply_filters('litespeed_optm_html_foot', $this->html_foot);
		if ($this->html_foot) {
			$this->content = str_replace('</body>', $this->html_foot . '</body>', $this->content);
		}

		// Drop noscript if enabled
		if ($this->conf(self::O_OPTM_NOSCRIPT_RM)) {
			// $this->content = preg_replace( '#<noscript>.*</noscript>#isU', '', $this->content );
		}

		// HTML minify
		if (defined('LITESPEED_GUEST_OPTM') || $this->conf(self::O_OPTM_HTML_MIN)) {
			$this->content = $this->__optimizer->html_min($this->content);
		}
	}

	/**
	 * Build a full JS tag
	 *
	 * @since  4.0
	 */
	private function _build_js_tag( $src ) {
		if ($this->cfg_js_defer === 2 || Utility::str_hit_array($src, $this->cfg_js_delay_inc)) {
			return '<script data-optimized="1" type="litespeed/javascript" data-src="' . Str::trim_quotes($src) . '"></script>';
		}

		if ($this->cfg_js_defer) {
			return '<script data-optimized="1" src="' . Str::trim_quotes($src) . '" defer></script>';
		}

		return '<script data-optimized="1" src="' . Str::trim_quotes($src) . '"></script>';
	}

	/**
	 * Build a full inline JS snippet
	 *
	 * @since  4.0
	 */
	private function _build_js_inline( $script, $minified = false ) {
		if ($this->cfg_js_defer) {
			$deferred = $this->_js_inline_defer($script, false, $minified);
			if ($deferred) {
				return $deferred;
			}
		}

		return '<script>' . $script . '</script>';
	}

	/**
	 * Load JS delay lib
	 *
	 * @since 4.0
	 */
	private function _maybe_js_delay() {
		if ($this->cfg_js_defer !== 2 && !$this->cfg_js_delay_inc) {
			return;
		}

		if (!defined('LITESPEED_JS_DELAY_LIB_LOADED')) {
			define('LITESPEED_JS_DELAY_LIB_LOADED', true);
			$this->html_foot .= '<script>' . File::read(LSCWP_DIR . self::LIB_FILE_JS_DELAY) . '</script>';
		}
	}

	/**
	 * Google font async
	 *
	 * @since 2.7.3
	 * @access private
	 */
	private function _async_ggfonts() {
		if (!$this->cfg_ggfonts_async || !$this->_ggfonts_urls) {
			return;
		}

		self::debug2('google fonts async found: ', $this->_ggfonts_urls);

		$this->html_head_early .= '<link rel="preconnect" href="https://fonts.gstatic.com/" crossorigin />';

		/**
		 * Append fonts
		 *
		 * Could be multiple fonts
		 *
		 *  <link rel='stylesheet' href='//fonts.googleapis.com/css?family=Open+Sans%3A400%2C600%2C700%2C800%2C300&#038;ver=4.9.8' type='text/css' media='all' />
		 *  <link rel='stylesheet' href='//fonts.googleapis.com/css?family=PT+Sans%3A400%2C700%7CPT+Sans+Narrow%3A400%7CMontserrat%3A600&#038;subset=latin&#038;ver=4.9.8' type='text/css' media='all' />
		 *      -> family: PT Sans:400,700|PT Sans Narrow:400|Montserrat:600
		 *  <link rel='stylesheet' href='https://fonts.googleapis.com/css?family=Source+Sans+Pro:400,300,300italic,400italic,600,700,900&#038;subset=latin%2Clatin-ext' />
		 */
		$script = 'WebFontConfig={google:{families:[';

		$families = array();
		foreach ($this->_ggfonts_urls as $v) {
			$qs = wp_specialchars_decode($v);
			$qs = urldecode($qs);
			$qs = parse_url($qs, PHP_URL_QUERY);
			parse_str($qs, $qs);

			if (empty($qs['family'])) {
				self::debug('ERR ggfonts failed to find family: ' . $v);
				continue;
			}

			$subset = empty($qs['subset']) ? '' : ':' . $qs['subset'];

			foreach (array_filter(explode('|', $qs['family'])) as $v2) {
				$families[] = Str::trim_quotes($v2 . $subset);
			}
		}

		$script .= '"' . implode('","', $families) . ($this->_conf_css_font_display ? '&display=swap' : '') . '"';

		$script .= ']}};';

		// if webfontloader lib was loaded before WebFontConfig variable, call WebFont.load
		$script .= 'if ( typeof WebFont === "object" && typeof WebFont.load === "function" ) { WebFont.load( WebFontConfig ); }';

		$html = $this->_build_js_inline($script);

		// https://cdnjs.cloudflare.com/ajax/libs/webfont/1.6.28/webfontloader.js
		$webfont_lib_url = LSWCP_PLUGIN_URL . self::LIB_FILE_WEBFONTLOADER;

		// default async, if js defer set use defer
		$html .= $this->_build_js_tag($webfont_lib_url);

		// Put this in the very beginning for preconnect
		$this->html_head = $html . $this->html_head;
	}

	/**
	 * Font optm
	 *
	 * @since  3.0
	 * @access private
	 */
	private function _font_optm() {
		if (!$this->_conf_css_font_display || !$this->_ggfonts_urls) {
			return;
		}

		self::debug2('google fonts optm ', $this->_ggfonts_urls);

		foreach ($this->_ggfonts_urls as $v) {
			if (strpos($v, 'display=')) {
				continue;
			}
			$this->html_head = str_replace($v, $v . '&#038;display=swap', $this->html_head);
			$this->html_foot = str_replace($v, $v . '&#038;display=swap', $this->html_foot);
			$this->content   = str_replace($v, $v . '&#038;display=swap', $this->content);
		}
	}

	/**
	 * Prefetch DNS
	 *
	 * @since 1.7.1 DNS prefetch
	 * @since 5.6.1 DNS preconnect
	 * @access private
	 */
	private function _dns_optm_init() {
		// Widely enable link DNS prefetch
		if (defined('LITESPEED_GUEST_OPTM') || $this->conf(self::O_OPTM_DNS_PREFETCH_CTRL)) {
			@header('X-DNS-Prefetch-Control: on');
		}

		$this->dns_prefetch = $this->conf(self::O_OPTM_DNS_PREFETCH);
		$this->dns_preconnect = $this->conf(self::O_OPTM_DNS_PRECONNECT);
		if (!$this->dns_prefetch && !$this->dns_preconnect) {
			return;
		}

		if (function_exists('wp_resource_hints')) {
			add_filter('wp_resource_hints', array( $this, 'dns_optm_filter' ), 10, 2);
		} else {
			add_action('litespeed_optm', array( $this, 'dns_optm_output' ));
		}
	}

	/**
	 * DNS optm hook for WP
	 *
	 * @since 1.7.1
	 * @access public
	 */
	public function dns_optm_filter( $urls, $relation_type ) {
		if ('dns-prefetch' === $relation_type) {
			foreach ($this->dns_prefetch as $v) {
				if ($v) {
					$urls[] = $v;
				}
			}
		}
		if ('preconnect' === $relation_type) {
			foreach ($this->dns_prefetch as $v) {
				if ($v) {
					$urls[] = $v;
				}
			}
		}

		return $urls;
	}

	/**
	 * DNS optm output directly
	 *
	 * @since 1.7.1 DNS prefetch
	 * @since 5.6.1 DNS preconnect
	 * @access public
	 */
	public function dns_optm_output() {
		foreach ($this->dns_prefetch as $v) {
			if ($v) {
				$this->html_head_early .= '<link rel="dns-prefetch" href="' . Str::trim_quotes($v) . '" />';
			}
		}
		foreach ($this->dns_preconnect as $v) {
			if ($v) {
				$this->html_head_early .= '<link rel="preconnect" href="' . Str::trim_quotes($v) . '" crossorigin />';
			}
		}
	}

	/**
	 * Run minify with src queue list
	 *
	 * @since  1.2.2
	 * @access private
	 */
	private function _src_queue_handler( $src_list, $html_list, $file_type = 'css' ) {
		$html_list_ori = $html_list;

		$can_webp = $this->cls('Media')->webp_support();

		$tag = $file_type == 'css' ? 'link' : 'script';
		foreach ($src_list as $key => $src_info) {
			// Minify inline CSS/JS
			if (!empty($src_info['inl'])) {
				if ($file_type == 'css') {
					$code = Optimizer::minify_css($src_info['src']);
					$can_webp && ($code = $this->cls('Media')->replace_background_webp($code));
					$snippet = str_replace($src_info['src'], $code, $html_list[$key]);
				} else {
					// Inline defer JS
					if ($this->cfg_js_defer) {
						$attrs   = !empty($src_info['attrs']) ? $src_info['attrs'] : '';
						$snippet = $this->_js_inline_defer($src_info['src'], $attrs) ?: $html_list[$key];
					} else {
						$code    = Optimizer::minify_js($src_info['src']);
						$snippet = str_replace($src_info['src'], $code, $html_list[$key]);
					}
				}
			}
			// CSS/JS files
			else {
				$url = $this->_build_single_hash_url($src_info['src'], $file_type);
				if ($url) {
					$snippet = str_replace($src_info['src'], $url, $html_list[$key]);
				}

				// Handle css async load
				if ($file_type == 'css' && $this->cfg_css_async) {
					$snippet = $this->_async_css($snippet);
				}

				// Handle js defer
				if ($file_type === 'js' && $this->cfg_js_defer) {
					$snippet = $this->_js_defer($snippet, $src_info['src']) ?: $snippet;
				}
			}

			$snippet         = str_replace("<$tag ", '<' . $tag . ' data-optimized="1" ', $snippet);
			$html_list[$key] = $snippet;
		}

		$this->content = str_replace($html_list_ori, $html_list, $this->content);
	}

	/**
	 * Build a single URL mapped filename (This will not save in DB)
	 *
	 * @since  4.0
	 */
	private function _build_single_hash_url( $src, $file_type = 'css' ) {
		$content = $this->__optimizer->load_file($src, $file_type);

		$is_min = $this->__optimizer->is_min($src);

		$content = $this->__optimizer->optm_snippet($content, $file_type, !$is_min, $src);

		$filepath_prefix = $this->_build_filepath_prefix($file_type);

		// Save to file
		$filename    = $filepath_prefix . md5($this->remove_query_strings($src)) . '.' . $file_type;
		$static_file = LITESPEED_STATIC_DIR . $filename;
		File::save($static_file, $content, true);

		// QS is required as $src may contains version info
		$qs_hash = substr(md5($src), -5);
		return LITESPEED_STATIC_URL . "$filename?ver=$qs_hash";
	}

	/**
	 * Generate full URL path with hash for a list of src
	 *
	 * @since  1.2.2
	 * @access private
	 */
	private function _build_hash_url( $src_list, $file_type = 'css' ) {
		// $url_sensitive = $this->conf( self::O_OPTM_CSS_UNIQUE ) && $file_type == 'css'; // If need to keep unique CSS per URI

		// Replace preserved ESI (before generating hash)
		if ($file_type == 'js') {
			foreach ($src_list as $k => $v) {
				if (empty($v['inl'])) {
					continue;
				}
				$src_list[$k]['src'] = $this->_preserve_esi($v['src']);
			}
		}

		$minify        = $file_type === 'css' ? $this->cfg_css_min : $this->cfg_js_min;
		$filename_info = $this->__optimizer->serve($this->_request_url, $file_type, $minify, $src_list);

		if (!$filename_info) {
			return false; // Failed to generate
		}

		list($filename, $type) = $filename_info;

		// Add cache tag in case later file deleted to avoid lscache served stale non-existed files @since 4.4.1
		Tag::add(Tag::TYPE_MIN . '.' . $filename);

		$qs_hash = substr(md5(self::get_option(self::ITEM_TIMESTAMP_PURGE_CSS)), -5);
		// As filename is already related to filecon md5, no need QS anymore
		$filepath_prefix = $this->_build_filepath_prefix($type);
		return LITESPEED_STATIC_URL . $filepath_prefix . $filename . '?ver=' . $qs_hash;
	}

	/**
	 * Parse js src
	 *
	 * @since  1.2.2
	 * @access private
	 */
	private function _parse_js() {
		$excludes = apply_filters('litespeed_optimize_js_excludes', $this->conf(self::O_OPTM_JS_EXC));

		$combine_ext_inl = $this->conf(self::O_OPTM_JS_COMB_EXT_INL);
		if (!apply_filters('litespeed_optm_js_comb_ext_inl', true)) {
			self::debug2('js_comb_ext_inl bypassed via litespeed_optm_js_comb_ext_inl filter');
			$combine_ext_inl = false;
		}

		$src_list  = array();
		$html_list = array();

		// V7 added: (?:\r\n?|\n?) to fix replacement leaving empty new line
		$content = preg_replace('#<!--.*-->(?:\r\n?|\n?)#sU', '', $this->content);
		preg_match_all('#<script([^>]*)>(.*)</script>(?:\r\n?|\n?)#isU', $content, $matches, PREG_SET_ORDER);
		foreach ($matches as $match) {
			$attrs = empty($match[1]) ? array() : Utility::parse_attr($match[1]);

			if (isset($attrs['data-optimized'])) {
				continue;
			}
			if (!empty($attrs['data-no-optimize'])) {
				continue;
			}
			if (!empty($attrs['data-cfasync']) && $attrs['data-cfasync'] === 'false') {
				continue;
			}
			if (!empty($attrs['type']) && $attrs['type'] != 'text/javascript') {
				continue;
			}

			// to avoid multiple replacement
			if (in_array($match[0], $html_list)) {
				continue;
			}

			$this_src_arr = array();
			// JS files
			if (!empty($attrs['src'])) {
				// Exclude check
				$js_excluded  = Utility::str_hit_array($attrs['src'], $excludes);
				$is_internal  = Utility::is_internal_file($attrs['src']);
				$is_file      = substr($attrs['src'], 0, 5) != 'data:';
				$ext_excluded = !$combine_ext_inl && !$is_internal;
				if ($js_excluded || $ext_excluded || !$is_file) {
					// Maybe defer
					if ($this->cfg_js_defer) {
						$deferred = $this->_js_defer($match[0], $attrs['src']);
						if ($deferred) {
							$this->content = str_replace($match[0], $deferred, $this->content);
						}
					}

					self::debug2('_parse_js bypassed due to ' . ($js_excluded ? 'js files excluded [hit] ' . $js_excluded : 'external js'));
					continue;
				}

				if (strpos($attrs['src'], '/localres/') !== false) {
					continue;
				}

				if (strpos($attrs['src'], 'instant_click') !== false) {
					continue;
				}

				$this_src_arr['src'] = $attrs['src'];
			}
			// Inline JS
			elseif (!empty($match[2])) {
				// self::debug( '🌹🌹🌹 ' . $match[2] . '🌹' );
				// Exclude check
				$js_excluded = Utility::str_hit_array($match[2], $excludes);
				if ($js_excluded || !$combine_ext_inl) {
					// Maybe defer
					if ($this->cfg_js_defer) {
						$deferred = $this->_js_inline_defer($match[2], $match[1]);
						if ($deferred) {
							$this->content = str_replace($match[0], $deferred, $this->content);
						}
					}
					self::debug2('_parse_js bypassed due to ' . ($js_excluded ? 'js excluded [hit] ' . $js_excluded : 'inline js'));
					continue;
				}

				$this_src_arr['inl'] = true;
				$this_src_arr['src'] = $match[2];
				if ($match[1]) {
					$this_src_arr['attrs'] = $match[1];
				}
			} else {
				// Compatibility to those who changed src to data-src already
				self::debug2('No JS src or inline JS content');
				continue;
			}

			$src_list[]  = $this_src_arr;
			$html_list[] = $match[0];
		}

		return array( $src_list, $html_list );
	}

	/**
	 * Inline JS defer
	 *
	 * @since 3.0
	 * @access private
	 */
	private function _js_inline_defer( $con, $attrs = false, $minified = false ) {
		if (strpos($attrs, 'data-no-defer') !== false) {
			self::debug2('bypass: attr api data-no-defer');
			return false;
		}

		$hit = Utility::str_hit_array($con, $this->cfg_js_defer_exc);
		if ($hit) {
			self::debug2('inline js defer excluded [setting] ' . $hit);
			return false;
		}

		$con = trim($con);
		// Minify JS first
		if (!$minified) {
			// && $this->cfg_js_defer !== 2
			$con = Optimizer::minify_js($con);
		}

		if (!$con) {
			return false;
		}

		// Check if the content contains ESI nonce or not
		$con = $this->_preserve_esi($con);

		if ($this->cfg_js_defer === 2) {
			// Drop type attribute from $attrs
			if (strpos($attrs, ' type=') !== false) {
				$attrs = preg_replace('# type=([\'"])([^\1]+)\1#isU', '', $attrs);
			}
			// Replace DOMContentLoaded
			$con = str_replace('DOMContentLoaded', 'DOMContentLiteSpeedLoaded', $con);
			return '<script' . $attrs . ' type="litespeed/javascript">' . $con . '</script>';
			// return '<script' . $attrs . ' type="litespeed/javascript" src="data:text/javascript;base64,' . base64_encode( $con ) . '"></script>';
			// return '<script' . $attrs . ' type="litespeed/javascript">' . $con . '</script>';
		}

		return '<script' . $attrs . ' src="data:text/javascript;base64,' . base64_encode($con) . '" defer></script>';
	}

	/**
	 * Replace ESI to JS inline var (mainly used to avoid nonce timeout)
	 *
	 * @since  3.5.1
	 */
	private function _preserve_esi( $con ) {
		$esi_placeholder_list = $this->cls('ESI')->contain_preserve_esi($con);
		if (!$esi_placeholder_list) {
			return $con;
		}

		foreach ($esi_placeholder_list as $esi_placeholder) {
			$js_var                   = '__litespeed_var_' . self::$_var_i++ . '__';
			$con                      = str_replace($esi_placeholder, $js_var, $con);
			$this->_var_preserve_js[] = $js_var . '=' . $esi_placeholder;
		}

		return $con;
	}

	/**
	 * Parse css src and remove to-be-removed css
	 *
	 * @since  1.2.2
	 * @access private
	 * @return array  All the src & related raw html list
	 */
	private function _parse_css() {
		$excludes             = apply_filters('litespeed_optimize_css_excludes', $this->conf(self::O_OPTM_CSS_EXC));
		$ucss_file_exc_inline = apply_filters('litespeed_optimize_ucss_file_exc_inline', $this->conf(self::O_OPTM_UCSS_FILE_EXC_INLINE));

		// Append dummy css to exclude list
		$excludes[] = 'litespeed-dummy.css';

		$combine_ext_inl = $this->conf(self::O_OPTM_CSS_COMB_EXT_INL);
		if (!apply_filters('litespeed_optm_css_comb_ext_inl', true)) {
			self::debug2('css_comb_ext_inl bypassed via litespeed_optm_css_comb_ext_inl filter');
			$combine_ext_inl = false;
		}

		$css_to_be_removed = apply_filters('litespeed_optm_css_to_be_removed', array());

		$src_list  = array();
		$html_list = array();

		// $dom = new \PHPHtmlParser\Dom;
		// $dom->load( $content );return $val;
		// $items = $dom->find( 'link' );

		// V7 added: (?:\r\n?|\n?) to fix replacement leaving empty new line
		$content = preg_replace(
			array( '#<!--.*-->(?:\r\n?|\n?)#sU', '#<script([^>]*)>.*</script>(?:\r\n?|\n?)#isU', '#<noscript([^>]*)>.*</noscript>(?:\r\n?|\n?)#isU' ),
			'',
			$this->content
		);
		preg_match_all('#<link ([^>]+)/?>|<style([^>]*)>([^<]+)</style>(?:\r\n?|\n?)#isU', $content, $matches, PREG_SET_ORDER);

		foreach ($matches as $match) {
			// to avoid multiple replacement
			if (in_array($match[0], $html_list)) {
				continue;
			}

			if ($exclude = Utility::str_hit_array($match[0], $excludes)) {
				self::debug2('_parse_css bypassed exclude ' . $exclude);
				continue;
			}

			$this_src_arr = array();
			if (strpos($match[0], '<link') === 0) {
				$attrs = Utility::parse_attr($match[1]);
				if (empty($attrs['rel']) || $attrs['rel'] !== 'stylesheet') {
					continue;
				}
				if (empty($attrs['href'])) {
					continue;
				}

				// Check if need to remove this css
				if (Utility::str_hit_array($attrs['href'], $css_to_be_removed)) {
					self::debug('rm css snippet ' . $attrs['href']);
					// Delete this css snippet from orig html
					$this->content = str_replace($match[0], '', $this->content);

					continue;
				}

				// Check if need to inline this css file
				if ($this->conf(self::O_OPTM_UCSS) && Utility::str_hit_array($attrs['href'], $ucss_file_exc_inline)) {
					self::debug('ucss_file_exc_inline hit ' . $attrs['href']);
					// Replace this css to inline from orig html
					$inline_script = '<style>' . $this->__optimizer->load_file($attrs['href']) . '</style>';
					$this->content = str_replace($match[0], $inline_script, $this->content);

					continue;
				}

				// Check Google fonts hit
				if (strpos($attrs['href'], 'fonts.googleapis.com') !== false) {
					/**
					 * For async gg fonts, will add webfont into head, hence remove it from buffer and store the matches to use later
					 *
					 * @since  2.7.3
					 * @since  3.0 For font display optm, need to parse google fonts URL too
					 */
					if (!in_array($attrs['href'], $this->_ggfonts_urls)) {
						$this->_ggfonts_urls[] = $attrs['href'];
					}

					if ($this->cfg_ggfonts_rm || $this->cfg_ggfonts_async) {
						self::debug('rm css snippet [Google fonts] ' . $attrs['href']);
						$this->content = str_replace($match[0], '', $this->content);

						continue;
					}
				}

				if (isset($attrs['data-optimized'])) {
					// $this_src_arr[ 'exc' ] = true;
					continue;
				} elseif (!empty($attrs['data-no-optimize'])) {
					// $this_src_arr[ 'exc' ] = true;
					continue;
				}

				$is_internal  = Utility::is_internal_file($attrs['href']);
				$ext_excluded = !$combine_ext_inl && !$is_internal;
				if ($ext_excluded) {
					self::debug2('Bypassed due to external link');
					// Maybe defer
					if ($this->cfg_css_async) {
						$snippet = $this->_async_css($match[0]);
						if ($snippet != $match[0]) {
							$this->content = str_replace($match[0], $snippet, $this->content);
						}
					}

					continue;
				}

				if (!empty($attrs['media']) && $attrs['media'] !== 'all') {
					$this_src_arr['media'] = $attrs['media'];
				}

				$this_src_arr['src'] = $attrs['href'];
			} else {
				// Inline style
				if (!$combine_ext_inl) {
					self::debug2('Bypassed due to inline');
					continue;
				}

				$attrs = Utility::parse_attr($match[2]);

				if (!empty($attrs['data-no-optimize'])) {
					continue;
				}

				if (!empty($attrs['media']) && $attrs['media'] !== 'all') {
					$this_src_arr['media'] = $attrs['media'];
				}

				$this_src_arr['inl'] = true;
				$this_src_arr['src'] = $match[3];
			}

			$src_list[] = $this_src_arr;

			$html_list[] = $match[0];
		}

		return array( $src_list, $html_list );
	}

	/**
	 * Replace css to async loaded css
	 *
	 * @since  1.3
	 * @access private
	 */
	private function _async_css_list( $html_list, $src_list ) {
		foreach ($html_list as $k => $ori) {
			if (!empty($src_list[$k]['inl'])) {
				continue;
			}

			$html_list[$k] = $this->_async_css($ori);
		}
		return $html_list;
	}

	/**
	 * Async CSS snippet
	 *
	 * @since 3.5
	 */
	private function _async_css( $ori ) {
		if (strpos($ori, 'data-asynced') !== false) {
			self::debug2('bypass: attr data-asynced exist');
			return $ori;
		}

		if (strpos($ori, 'data-no-async') !== false) {
			self::debug2('bypass: attr api data-no-async');
			return $ori;
		}

		// async replacement
		$v = str_replace('stylesheet', 'preload', $ori);
		$v = str_replace('<link', '<link data-asynced="1" as="style" onload="this.onload=null;this.rel=\'stylesheet\'" ', $v);
		// Append to noscript content
		if (!defined('LITESPEED_GUEST_OPTM') && !$this->conf(self::O_OPTM_NOSCRIPT_RM)) {
			$v .= '<noscript>' . preg_replace('/ id=\'[\w-]+\' /U', ' ', $ori) . '</noscript>';
		}

		return $v;
	}

	/**
	 * Defer JS snippet
	 *
	 * @since  3.5
	 */
	private function _js_defer( $ori, $src ) {
		if (strpos($ori, ' async') !== false) {
			$ori = preg_replace('# async(?:=([\'"])(?:[^\1]*?)\1)?#is', '', $ori);
		}

		if (strpos($ori, 'defer') !== false) {
			return false;
		}
		if (strpos($ori, 'data-deferred') !== false) {
			self::debug2('bypass: attr data-deferred exist');
			return false;
		}
		if (strpos($ori, 'data-no-defer') !== false) {
			self::debug2('bypass: attr api data-no-defer');
			return false;
		}

		/**
		 * Exclude JS from setting
		 *
		 * @since 1.5
		 */
		if (Utility::str_hit_array($src, $this->cfg_js_defer_exc)) {
			self::debug('js defer exclude ' . $src);
			return false;
		}

		if ($this->cfg_js_defer === 2 || Utility::str_hit_array($src, $this->cfg_js_delay_inc)) {
			if (strpos($ori, ' type=') !== false) {
				$ori = preg_replace('# type=([\'"])([^\1]+)\1#isU', '', $ori);
			}
			return str_replace(' src=', ' type="litespeed/javascript" data-src=', $ori);
		}

		return str_replace('></script>', ' defer data-deferred="1"></script>', $ori);
	}

	/**
	 * Delay JS for included setting
	 *
	 * @since 5.6
	 */
	private function _js_delay( $ori, $src ) {
		if (strpos($ori, ' async') !== false) {
			$ori = str_replace(' async', '', $ori);
		}

		if (strpos($ori, 'defer') !== false) {
			return false;
		}
		if (strpos($ori, 'data-deferred') !== false) {
			self::debug2('bypass: attr data-deferred exist');
			return false;
		}
		if (strpos($ori, 'data-no-defer') !== false) {
			self::debug2('bypass: attr api data-no-defer');
			return false;
		}

		if (!Utility::str_hit_array($src, $this->cfg_js_delay_inc)) {
			return;
		}

		if (strpos($ori, ' type=') !== false) {
			$ori = preg_replace('# type=([\'"])([^\1]+)\1#isU', '', $ori);
		}
		return str_replace(' src=', ' type="litespeed/javascript" data-src=', $ori);
	}
}
