<?php
/**
 * The htaccess rewrite rule operation class
 *
 *
 * @since      1.0.0
 * @package    LiteSpeed
 * @subpackage LiteSpeed/inc
 * @author     LiteSpeed Technologies <info@litespeedtech.com>
 */
namespace LiteSpeed;

defined( 'WPINC' ) || exit;

class Htaccess extends Root {
	private $frontend_htaccess = null;
	private $_default_frontend_htaccess = null;
	private $backend_htaccess = null;
	private $_default_backend_htaccess = null;
	private $theme_htaccess = null;// Not used yet
	private $frontend_htaccess_readable = false;
	private $frontend_htaccess_writable = false;
	private $backend_htaccess_readable = false;
	private $backend_htaccess_writable = false;
	private $theme_htaccess_readable = false;
	private $theme_htaccess_writable = false;
	private $__rewrite_on;

	const LS_MODULE_START = '<IfModule LiteSpeed>';
	const EXPIRES_MODULE_START = '<IfModule mod_expires.c>';
	const LS_MODULE_END = '</IfModule>';
	const LS_MODULE_REWRITE_START = '<IfModule mod_rewrite.c>';
	const REWRITE_ON = 'RewriteEngine on';
	const LS_MODULE_DONOTEDIT = "## LITESPEED WP CACHE PLUGIN - Do not edit the contents of this block! ##";
	const MARKER = 'LSCACHE';
	const MARKER_NONLS = 'NON_LSCACHE';
	const MARKER_LOGIN_COOKIE = '### marker LOGIN COOKIE';
	const MARKER_MOBILE = '### marker MOBILE';
	const MARKER_NOCACHE_COOKIES = '### marker NOCACHE COOKIES';
	const MARKER_NOCACHE_USER_AGENTS = '### marker NOCACHE USER AGENTS';
	const MARKER_CACHE_RESOURCE = '### marker CACHE RESOURCE';
	const MARKER_FAVICON = '### marker FAVICON';
	const MARKER_BROWSER_CACHE = '### marker BROWSER CACHE';
	const MARKER_MINIFY = '### marker MINIFY';
	const MARKER_CORS = '### marker CORS';
	const MARKER_WEBP = '### marker WEBP';
	const MARKER_DROPQS = '### marker DROPQS';
	const MARKER_START = ' start ###';
	const MARKER_END = ' end ###';

	const RW_PATTERN_RES = '/.*/[^/]*(responsive|css|js|dynamic|loader|fonts)\.php';

	/**
	 * Initialize the class and set its properties.
	 *
	 * @since    1.0.7
	 */
	public function __construct() {
		$this->_path_set();
		$this->_default_frontend_htaccess = $this->frontend_htaccess;
		$this->_default_backend_htaccess = $this->backend_htaccess;

		$frontend_htaccess = defined( 'LITESPEED_CFG_HTACCESS' ) ? LITESPEED_CFG_HTACCESS : false;
		if ( $frontend_htaccess && substr( $frontend_htaccess, -10 ) === '/.htaccess' ) {
			$this->frontend_htaccess = $frontend_htaccess;
		}
		$backend_htaccess = defined( 'LITESPEED_CFG_HTACCESS_BACKEND' ) ? LITESPEED_CFG_HTACCESS_BACKEND : false;
		if ( $backend_htaccess && substr( $backend_htaccess, -10 ) === '/.htaccess' ) {
			$this->backend_htaccess = $backend_htaccess;
		}

		// Filter for frontend&backend htaccess path
		$this->frontend_htaccess = apply_filters( 'litespeed_frontend_htaccess', $this->frontend_htaccess );
		$this->backend_htaccess = apply_filters( 'litespeed_backend_htaccess', $this->backend_htaccess );

		clearstatcache();

		// frontend .htaccess privilege
		$test_permissions = file_exists( $this->frontend_htaccess ) ? $this->frontend_htaccess : dirname( $this->frontend_htaccess );
		if ( is_readable( $test_permissions ) ) {
			$this->frontend_htaccess_readable = true;
		}
		if ( is_writable( $test_permissions ) ) {
			$this->frontend_htaccess_writable = true;
		}

		$this->__rewrite_on = array(
			self::REWRITE_ON,
			"CacheLookup on",
			"RewriteRule .* - [E=Cache-Control:no-autoflush]",
			// "RewriteRule \.object-cache\.ini - [F,L]",
			'RewriteRule ' . preg_quote( self::CONF_FILE ) . ' - [F,L]',
		);

		// backend .htaccess privilege
		if ( $this->frontend_htaccess === $this->backend_htaccess ) {
			$this->backend_htaccess_readable = $this->frontend_htaccess_readable;
			$this->backend_htaccess_writable = $this->frontend_htaccess_writable;
		}
		else {
			$test_permissions = file_exists( $this->backend_htaccess ) ? $this->backend_htaccess : dirname( $this->backend_htaccess );
			if ( is_readable( $test_permissions ) ) {
				$this->backend_htaccess_readable = true;
			}
			if ( is_writable( $test_permissions ) ) {
				$this->backend_htaccess_writable = true;
			}
		}
	}

	/**
	 * Get if htaccess file is readable
	 *
	 * @since 1.1.0
	 * @return string
	 */
	private function _readable( $kind = 'frontend' ) {
		if( $kind === 'frontend' ) {
			return $this->frontend_htaccess_readable;
		}
		if( $kind === 'backend' ) {
			return $this->backend_htaccess_readable;
		}
	}

	/**
	 * Get if htaccess file is writable
	 *
	 * @since 1.1.0
	 * @return string
	 */
	public function writable( $kind = 'frontend' ) {
		if( $kind === 'frontend' ) {
			return $this->frontend_htaccess_writable;
		}
		if( $kind === 'backend' ) {
			return $this->backend_htaccess_writable;
		}
	}

	/**
	 * Get frontend htaccess path
	 *
	 * @since 1.1.0
	 * @return string
	 */
	public static function get_frontend_htaccess( $show_default = false ) {
		if ( $show_default ) {
			return self::cls()->_default_frontend_htaccess;
		}
		return self::cls()->frontend_htaccess;
	}

	/**
	 * Get backend htaccess path
	 *
	 * @since 1.1.0
	 * @return string
	 */
	public static function get_backend_htaccess( $show_default = false ) {
		if ( $show_default ) {
			return self::cls()->_default_backend_htaccess;
		}
		return self::cls()->backend_htaccess;
	}

	/**
	 * Check to see if .htaccess exists starting at $start_path and going up directories until it hits DOCUMENT_ROOT.
	 *
	 * As dirname() strips the ending '/', paths passed in must exclude the final '/'
	 *
	 * @since 1.0.11
	 * @access private
	 */
	private function _htaccess_search( $start_path ) {
		while ( ! file_exists( $start_path . '/.htaccess' ) ) {
			if ( $start_path === '/' || ! $start_path ) {
				return false;
			}

			if ( ! empty( $_SERVER[ 'DOCUMENT_ROOT' ] ) && wp_normalize_path( $start_path ) === wp_normalize_path( $_SERVER[ 'DOCUMENT_ROOT' ] ) ) {
				return false;
			}

			if ( dirname( $start_path ) === $start_path ) {
				return false;
			}

			$start_path = dirname( $start_path );
		}

		return $start_path;
	}

	/**
	 * Set the path class variables.
	 *
	 * @since 1.0.11
	 * @access private
	 */
	private function _path_set() {
		$frontend = Router::frontend_path();
		$frontend_htaccess_search = $this->_htaccess_search( $frontend );// The existing .htaccess path to be used for frontend .htaccess
		$this->frontend_htaccess = ( $frontend_htaccess_search ?: $frontend ) . '/.htaccess';

		$backend = realpath( ABSPATH ); // /home/user/public_html/backend/
		if ( $frontend == $backend ) {
			$this->backend_htaccess = $this->frontend_htaccess;
			return;
		}

		// Backend is a different path
		$backend_htaccess_search = $this->_htaccess_search( $backend );
		// Found affected .htaccess
		if ( $backend_htaccess_search ) {
			$this->backend_htaccess = $backend_htaccess_search . '/.htaccess';
			return;
		}

		// Frontend path is the parent of backend path
		if ( stripos( $backend, $frontend . '/' ) === 0 ) {
			// backend use frontend htaccess
			$this->backend_htaccess = $this->frontend_htaccess;
			return;
		}

		$this->backend_htaccess = $backend . '/.htaccess';
	}

	/**
	 * Get corresponding htaccess path
	 *
	 * @since 1.1.0
	 * @param  string $kind Frontend or backend
	 * @return string       Path
	 */
	public function htaccess_path( $kind = 'frontend' ) {
		switch ( $kind ) {
			case 'backend' :
				$path = $this->backend_htaccess;
				break;

			case 'frontend' :
			default :
				$path = $this->frontend_htaccess;
				break;
		}
		return $path;
	}

	/**
	 * Get the content of the rules file.
	 *
	 * NOTE: will throw error if failed
	 *
	 * @since 1.0.4
	 * @since  2.9 Used exception for failed reading
	 * @access public
	 */
	public function htaccess_read( $kind = 'frontend' ) {
		$path = $this->htaccess_path( $kind );

		if( ! $path || ! file_exists( $path ) ) {
			return "\n";
		}

		if ( ! $this->_readable( $kind ) ) {
			Error::t( 'HTA_R' );
		}

		$content = File::read( $path );
		if ( $content === false ) {
			Error::t( 'HTA_GET' );
		}

		// Remove ^M characters.
		$content = str_ireplace( "\x0D", "", $content );
		return $content;
	}

	/**
	 * Try to backup the .htaccess file if we didn't save one before.
	 *
	 * NOTE: will throw error if failed
	 *
	 * @since 1.0.10
	 * @access private
	 */
	private function _htaccess_backup( $kind = 'frontend' ) {
		$path = $this->htaccess_path( $kind );

		if ( ! file_exists( $path ) ) {
			return;
		}

		if ( file_exists( $path . '.bk' ) ) {
			return;
		}

		$res = copy( $path, $path . '.bk' );

		// Failed to backup, abort
		if ( ! $res ) {
			Error::t( 'HTA_BK' );
		}
	}

	/**
	 * Get mobile view rule from htaccess file
	 *
	 * NOTE: will throw error if failed
	 *
	 * @since 1.1.0
	 */
	public function current_mobile_agents() {
		$rules = $this->_get_rule_by( self::MARKER_MOBILE );
		if( ! isset( $rules[ 0 ] ) ) {
			Error::t( 'HTA_DNF', self::MARKER_MOBILE );
		}

		$rule = trim( $rules[ 0 ] );
		// 'RewriteCond %{HTTP_USER_AGENT} ' . Utility::arr2regex( $cfg[ $id ], true ) . ' [NC]';
		$match = substr( $rule, strlen( 'RewriteCond %{HTTP_USER_AGENT} ' ), -strlen( ' [NC]' ) );

		if ( ! $match ) {
			Error::t( 'HTA_DNF', __( 'Mobile Agent Rules', 'litespeed-cache' ) );
		}

		return $match;
	}

	/**
	 * Parse rewrites rule from the .htaccess file.
	 *
	 * NOTE: will throw error if failed
	 *
	 * @since 1.1.0
	 * @access public
	 */
	public function current_login_cookie( $kind = 'frontend' ) {
		$rule = $this->_get_rule_by( self::MARKER_LOGIN_COOKIE, $kind );

		if( ! $rule ) {
			Error::t( 'HTA_DNF', self::MARKER_LOGIN_COOKIE );
		}

		if( strpos( $rule, 'RewriteRule .? - [E=' ) !== 0 ) {
			Error::t( 'HTA_LOGIN_COOKIE_INVALID' );
		}

		$rule_cookie = substr( $rule, strlen( 'RewriteRule .? - [E=' ), -1 );

		if ( LITESPEED_SERVER_TYPE === 'LITESPEED_SERVER_OLS' ) {
			$rule_cookie = trim( $rule_cookie, '"' );
		}

		// Drop `Cache-Vary:`
		$rule_cookie = substr( $rule_cookie, strlen( 'Cache-Vary:' ) );

		return $rule_cookie;
	}

	/**
	 * Get rewrite rules based on the marker
	 *
	 * @since  2.0
	 * @access private
	 */
	private function _get_rule_by( $cond, $kind = 'frontend' ) {
		clearstatcache();
		$path = $this->htaccess_path( $kind );
		if ( ! $this->_readable( $kind ) ) {
			return false;
		}

		$rules = File::extract_from_markers( $path, self::MARKER );
		if( ! in_array( $cond . self::MARKER_START, $rules ) || ! in_array( $cond . self::MARKER_END, $rules ) ) {
			return false;
		}

		$key_start = array_search( $cond . self::MARKER_START, $rules );
		$key_end = array_search( $cond . self::MARKER_END, $rules );
		if( $key_start === false || $key_end === false ) {
			return false;
		}

		$results = array_slice( $rules, $key_start + 1, $key_end - $key_start - 1 );
		if( ! $results ) {
			return false;
		}

		if( count( $results ) == 1 ) {
			return trim( $results[ 0 ] );
		}

		return array_filter( $results );
	}

	/**
	 * Generate browser cache rules
	 *
	 * @since  1.3
	 * @access private
	 * @return array Rules set
	 */
	private function _browser_cache_rules( $cfg ) {
		/**
		 * Add ttl setting
		 * @since 1.6.3
		 */
		$id = Base::O_CACHE_TTL_BROWSER;
		$ttl = $cfg[ $id ];
		$rules = array(
			self::EXPIRES_MODULE_START,
			// '<FilesMatch "\.(pdf|ico|svg|xml|jpg|jpeg|png|gif|webp|ogg|mp4|webm|js|css|woff|woff2|ttf|eot)(\.gz)?$">',
				'ExpiresActive on',
				'ExpiresByType application/pdf A' . $ttl,
				'ExpiresByType image/x-icon A' . $ttl,
				'ExpiresByType image/vnd.microsoft.icon A' . $ttl,
				'ExpiresByType image/svg+xml A' . $ttl,
				'',
				'ExpiresByType image/jpg A' . $ttl,
				'ExpiresByType image/jpeg A' . $ttl,
				'ExpiresByType image/png A' . $ttl,
				'ExpiresByType image/gif A' . $ttl,
				'ExpiresByType image/webp A' . $ttl,
				'',
				'ExpiresByType video/ogg A' . $ttl,
				'ExpiresByType audio/ogg A' . $ttl,
				'ExpiresByType video/mp4 A' . $ttl,
				'ExpiresByType video/webm A' . $ttl,
				'',
				'ExpiresByType text/css A' . $ttl,
				'ExpiresByType text/javascript A' . $ttl,
				'ExpiresByType application/javascript A' . $ttl,
				'ExpiresByType application/x-javascript A' . $ttl,
				'',
				'ExpiresByType application/x-font-ttf A' . $ttl,
				'ExpiresByType application/x-font-woff A' . $ttl,
				'ExpiresByType application/font-woff A' . $ttl,
				'ExpiresByType application/font-woff2 A' . $ttl,
				'ExpiresByType application/vnd.ms-fontobject A' . $ttl,
				'ExpiresByType font/ttf A' . $ttl,
				'ExpiresByType font/otf A' . $ttl,
				'ExpiresByType font/woff A' . $ttl,
				'ExpiresByType font/woff2 A' . $ttl,
				'',
			// '</FilesMatch>',
			self::LS_MODULE_END,
		);
		return $rules;
	}

	/**
	 * Generate CORS rules for fonts
	 *
	 * @since  1.5
	 * @access private
	 * @return array Rules set
	 */
	private function _cors_rules() {
		return array(
			'<FilesMatch "\.(ttf|ttc|otf|eot|woff|woff2|font\.css)$">',
				'<IfModule mod_headers.c>',
					'Header set Access-Control-Allow-Origin "*"',
				'</IfModule>',
			'</FilesMatch>',
		);
	}

	/**
	 * Generate rewrite rules based on settings
	 *
	 * @since  1.3
	 * @access private
	 * @param  array $cfg  The settings to be used for rewrite rule
	 * @return array      Rules array
	 */
	private function _generate_rules( $cfg ) {
		$new_rules = array();
		$new_rules_nonls = array();
		$new_rules_backend = array();
		$new_rules_backend_nonls = array();

		// mobile agents
		$id = Base::O_CACHE_MOBILE_RULES;
		if ( ( ! empty( $cfg[ Base::O_CACHE_MOBILE ] ) || ! empty( $cfg[ Base::O_GUEST ] ) ) && ! empty( $cfg[ $id ] ) ) {
			$new_rules[] = self::MARKER_MOBILE . self::MARKER_START;
			$new_rules[] = 'RewriteCond %{HTTP_USER_AGENT} ' . Utility::arr2regex( $cfg[ $id ], true ) . ' [NC]';
			$new_rules[] = 'RewriteRule .* - [E=Cache-Control:vary=%{ENV:LSCACHE_VARY_VALUE}+ismobile]';
			$new_rules[] = self::MARKER_MOBILE . self::MARKER_END;
			$new_rules[] = '';
		}

		// nocache cookie
		$id = Base::O_CACHE_EXC_COOKIES;
		if ( ! empty( $cfg[ $id ] ) ) {
			$new_rules[] = self::MARKER_NOCACHE_COOKIES . self::MARKER_START;
			$new_rules[] = 'RewriteCond %{HTTP_COOKIE} ' .  Utility::arr2regex( $cfg[ $id ], true );
			$new_rules[] = 'RewriteRule .* - [E=Cache-Control:no-cache]';
			$new_rules[] = self::MARKER_NOCACHE_COOKIES . self::MARKER_END;
			$new_rules[] = '';
		}

		// nocache user agents
		$id = Base::O_CACHE_EXC_USERAGENTS;
		if ( ! empty( $cfg[ $id ] ) ) {
			$new_rules[] = self::MARKER_NOCACHE_USER_AGENTS . self::MARKER_START;
			$new_rules[] = 'RewriteCond %{HTTP_USER_AGENT} ' . Utility::arr2regex( $cfg[ $id ], true );
			$new_rules[] = 'RewriteRule .* - [E=Cache-Control:no-cache]';
			$new_rules[] = self::MARKER_NOCACHE_USER_AGENTS . self::MARKER_END;
			$new_rules[] = '';
		}

		// caching php resource
		$id = Base::O_CACHE_RES;
		if ( ! empty( $cfg[ $id ] ) ) {
			$new_rules[] = $new_rules_backend[] = self::MARKER_CACHE_RESOURCE . self::MARKER_START;
			$new_rules[] = $new_rules_backend[] = 'RewriteRule ' . LSCWP_CONTENT_FOLDER . self::RW_PATTERN_RES . ' - [E=cache-control:max-age=3600]';
			$new_rules[] = $new_rules_backend[] = self::MARKER_CACHE_RESOURCE . self::MARKER_END;
			$new_rules[] = $new_rules_backend[] = '';
		}

		// check login cookie
		$id = Base::O_CACHE_LOGIN_COOKIE;
		$vary_cookies = $cfg[ $id ] ? array( $cfg[ $id ] ) : array();
		if ( LITESPEED_SERVER_TYPE === 'LITESPEED_SERVER_OLS' ) { // Need to keep this due to different behavior of OLS when handling response vary header @Sep/22/2018
			if ( defined( 'COOKIEHASH' ) ) {
				$vary_cookies[] = ',wp-postpass_' . COOKIEHASH;
			}
			$vary_cookies = apply_filters( 'litespeed_vary_cookies', $vary_cookies ); // todo: test if response vary header can work in latest OLS, drop the above two lines
		}
		// frontend and backend
		if ( $vary_cookies ) {
			$env = 'Cache-Vary:' . implode( ',', $vary_cookies );
			if ( LITESPEED_SERVER_TYPE === 'LITESPEED_SERVER_OLS' ) {
				$env = '"' . $env . '"';
			}
			$new_rules[] = $new_rules_backend[] = self::MARKER_LOGIN_COOKIE . self::MARKER_START;
			$new_rules[] = $new_rules_backend[] = 'RewriteRule .? - [E=' . $env . ']';
			$new_rules[] = $new_rules_backend[] = self::MARKER_LOGIN_COOKIE . self::MARKER_END;
			$new_rules[] = '';
		}

		// favicon
		// frontend and backend
		$id = Base::O_CACHE_FAVICON;
		if ( ! empty( $cfg[ $id ] ) ) {
			$new_rules[] = $new_rules_backend[] = self::MARKER_FAVICON . self::MARKER_START;
			$new_rules[] = $new_rules_backend[] = 'RewriteRule favicon\.ico$ - [E=cache-control:max-age=86400]';
			$new_rules[] = $new_rules_backend[] = self::MARKER_FAVICON . self::MARKER_END;
			$new_rules[] = '';
		}

		// CORS font rules
		$id = Base::O_CDN;
		if ( ! empty( $cfg[ $id ] ) ) {
			$new_rules[] = self::MARKER_CORS . self::MARKER_START;
			$new_rules = array_merge( $new_rules, $this->_cors_rules() ); //todo: network
			$new_rules[] = self::MARKER_CORS . self::MARKER_END;
			$new_rules[] = '';
		}

		// webp support
		$id = Base::O_IMG_OPTM_WEBP_REPLACE;
		if ( ! empty( $cfg[ $id ] ) || ! empty( $cfg[ Base::O_GUEST ] ) ) {
			$new_rules[] = self::MARKER_WEBP . self::MARKER_START;
			$new_rules[] = 'RewriteCond %{HTTP_ACCEPT} "image/webp" [or]';
			$new_rules[] = 'RewriteCond %{HTTP_USER_AGENT} "Page Speed"';
			$new_rules[] = 'RewriteRule .* - [E=Cache-Control:vary=%{ENV:LSCACHE_VARY_VALUE}+webp]';
			$new_rules[] = 'RewriteCond %{HTTP_USER_AGENT} iPhone.*Version/(\d{2}).*Safari';
			$new_rules[] = 'RewriteCond %1 >13';
			$new_rules[] = 'RewriteRule .* - [E=Cache-Control:vary=%{ENV:LSCACHE_VARY_VALUE}+webp]';
			$new_rules[] = self::MARKER_WEBP . self::MARKER_END;
			$new_rules[] = '';
		}

		// drop qs support
		$id = Base::O_CACHE_DROP_QS;
		if ( ! empty( $cfg[ $id ] ) ) {
			$new_rules[] = self::MARKER_DROPQS . self::MARKER_START;
			foreach ( $cfg[ $id ] as $v ) {
				$new_rules[] = 'CacheKeyModify -qs:' . $v;
			}
			$new_rules[] = self::MARKER_DROPQS . self::MARKER_END;
			$new_rules[] = '';
		}

		// Browser cache
		$id = Base::O_CACHE_BROWSER;
		if ( ! empty( $cfg[ $id ] ) ) {
			$new_rules_nonls[] = $new_rules_backend_nonls[] = self::MARKER_BROWSER_CACHE . self::MARKER_START;
			$new_rules_nonls = array_merge( $new_rules_nonls, $this->_browser_cache_rules( $cfg ) );
			$new_rules_backend_nonls = array_merge( $new_rules_backend_nonls, $this->_browser_cache_rules( $cfg ) );
			$new_rules_nonls[] = $new_rules_backend_nonls[] = self::MARKER_BROWSER_CACHE . self::MARKER_END;
			$new_rules_nonls[] = '';
		}

		// Add module wrapper for LiteSpeed rules
		if ( $new_rules ) {
			$new_rules = $this->_wrap_ls_module( $new_rules );
		}

		if ( $new_rules_backend ) {
			$new_rules_backend = $this->_wrap_ls_module( $new_rules_backend );
		}

		return array( $new_rules, $new_rules_backend, $new_rules_nonls, $new_rules_backend_nonls );
	}

	/**
	 * Add LitSpeed module wrapper with rewrite on
	 *
	 * @since  2.1.1
	 * @access private
	 */
	private function _wrap_ls_module( $rules = array() ) {
		return array_merge(
			array( self::LS_MODULE_START ),
			$this->__rewrite_on,
			array( '' ),
			$rules,
			array( self::LS_MODULE_END )
		);
	}

	/**
	 * Insert LitSpeed module wrapper with rewrite on
	 *
	 * @since  2.1.1
	 * @access public
	 */
	public function insert_ls_wrapper() {
		$rules = $this->_wrap_ls_module();
		$this->_insert_wrapper( $rules );
	}

	/**
	 * wrap rules with module on info
	 *
	 * @since  1.1.5
	 * @param  array  $rules
	 * @return array        wrapped rules with module info
	 */
	private function _wrap_do_no_edit( $rules ) {
		// When to clear rules, don't need DONOTEDIT msg
		if ( $rules === false || ! is_array( $rules ) ) {
			return $rules;
		}

		$rules = array_merge(
			array( self::LS_MODULE_DONOTEDIT ),
			$rules,
			array( self::LS_MODULE_DONOTEDIT )
		);

		return $rules;
	}

	/**
	 * Write to htaccess with rules
	 *
	 * NOTE: will throw error if failed
	 *
	 * @since  1.1.0
	 * @access private
	 */
	private function _insert_wrapper( $rules = array(), $kind = false, $marker = false ) {
		if ( $kind != 'backend' ) {
			$kind = 'frontend';
		}

		// Default marker is LiteSpeed marker `LSCACHE`
		if ( $marker === false ) {
			$marker = self::MARKER;
		}

		$this->_htaccess_backup( $kind );

		File::insert_with_markers( $this->htaccess_path( $kind ), $this->_wrap_do_no_edit( $rules ), $marker, true );
	}

	/**
	 * Update rewrite rules based on setting
	 *
	 * NOTE: will throw error if failed
	 *
	 * @since 1.3
	 * @access public
	 */
	public function update( $cfg ) {
		list( $frontend_rules, $backend_rules, $frontend_rules_nonls, $backend_rules_nonls ) = $this->_generate_rules( $cfg );

		// Check frontend content
		list( $rules, $rules_nonls ) = $this->_extract_rules();

		// Check Non-LiteSpeed rules
		if ( $this->_wrap_do_no_edit( $frontend_rules_nonls ) != $rules_nonls ) {
			Debug2::debug( '[Rules] Update non-ls frontend rules' );
			// Need to update frontend htaccess
			try {
				$this->_insert_wrapper( $frontend_rules_nonls, false, self::MARKER_NONLS );
			} catch ( \Exception $e ) {
				$manual_guide_codes = $this->_rewrite_codes_msg( $this->frontend_htaccess, $frontend_rules_nonls, self::MARKER_NONLS );
				Debug2::debug( '[Rules] Update Failed' );
				throw new \Exception( $manual_guide_codes );
			}
		}

		// Check LiteSpeed rules
		if ( $this->_wrap_do_no_edit( $frontend_rules ) != $rules ) {
			Debug2::debug( '[Rules] Update frontend rules' );
			// Need to update frontend htaccess
			try {
				$this->_insert_wrapper( $frontend_rules );
			} catch ( \Exception $e ) {
				Debug2::debug( '[Rules] Update Failed' );
				$manual_guide_codes = $this->_rewrite_codes_msg( $this->frontend_htaccess, $frontend_rules );
				throw new \Exception( $manual_guide_codes );
			}
		}

		if ( $this->frontend_htaccess !== $this->backend_htaccess ) {
			list( $rules, $rules_nonls ) = $this->_extract_rules( 'backend' );

			// Check Non-LiteSpeed rules for backend
			if ( $this->_wrap_do_no_edit( $backend_rules_nonls ) != $rules_nonls ) {
				Debug2::debug( '[Rules] Update non-ls backend rules' );
				// Need to update frontend htaccess
				try {
					$this->_insert_wrapper( $backend_rules_nonls, 'backend', self::MARKER_NONLS );
				} catch ( \Exception $e ) {
					Debug2::debug( '[Rules] Update Failed' );
					$manual_guide_codes = $this->_rewrite_codes_msg( $this->backend_htaccess, $backend_rules_nonls, self::MARKER_NONLS );
					throw new \Exception( $manual_guide_codes );
				}
			}

			// Check backend content
			if ( $this->_wrap_do_no_edit( $backend_rules ) != $rules ) {
				Debug2::debug( '[Rules] Update backend rules' );
				// Need to update backend htaccess
				try {
					$this->_insert_wrapper( $backend_rules, 'backend' );
				} catch ( \Exception $e ) {
					Debug2::debug( '[Rules] Update Failed' );
					$manual_guide_codes = $this->_rewrite_codes_msg( $this->backend_htaccess, $backend_rules );
					throw new \Exception( $manual_guide_codes );
				}
			}
		}

		return true;
	}

	/**
	 * Get existing rewrite rules
	 *
	 * NOTE: will throw error if failed
	 *
	 * @since  1.3
	 * @access private
	 * @param  string $kind Frontend or backend .htaccess file
	 */
	private function _extract_rules( $kind = 'frontend' ) {
		clearstatcache();
		$path = $this->htaccess_path( $kind );
		if ( ! $this->_readable( $kind ) ) {
			Error::t( 'E_HTA_R' );
		}

		$rules = File::extract_from_markers( $path, self::MARKER );
		$rules_nonls = File::extract_from_markers( $path, self::MARKER_NONLS );

		return array( $rules, $rules_nonls );
	}

	/**
	 * Output the msg with rules plain data for manual insert
	 *
	 * @since  1.1.5
	 * @param  string  $file
	 * @param  array  $rules
	 * @return string        final msg to output
	 */
	private function _rewrite_codes_msg( $file, $rules, $marker = false ) {
		return sprintf( __( '<p>Please add/replace the following codes into the beginning of %1$s:</p> %2$s' , 'litespeed-cache' ),
				$file,
				'<textarea style="width:100%;" rows="10" readonly>' . htmlspecialchars( $this->_wrap_rules_with_marker( $rules, $marker ) ) . '</textarea>'
			);
	}

	/**
	 * Generate rules plain data for manual insert
	 *
	 * @since  1.1.5
	 */
	private function _wrap_rules_with_marker( $rules, $marker = false ) {
		// Default marker is LiteSpeed marker `LSCACHE`
		if ( $marker === false ) {
			$marker = self::MARKER;
		}

		$start_marker = "# BEGIN {$marker}";
		$end_marker   = "# END {$marker}";
		$new_file_data = implode( "\n", array_merge(
			array( $start_marker ),
			$this->_wrap_do_no_edit($rules),
			array( $end_marker )
		) );

		return $new_file_data;
	}

	/**
	 * Clear the rules file of any changes added by the plugin specifically.
	 *
	 * @since 1.0.4
	 * @access public
	 */
	public function clear_rules() {
		$this->_insert_wrapper( false );// Use false to avoid do-not-edit msg
		// Clear non ls rules
		$this->_insert_wrapper( false, false, self::MARKER_NONLS );

		if ( $this->frontend_htaccess !== $this->backend_htaccess ) {
			$this->_insert_wrapper( false, 'backend' );
			$this->_insert_wrapper( false, 'backend', self::MARKER_NONLS );
		}
	}
}

