<?php
namespace W3TC;

/**
 * class PgCache_Environment
 */
class PgCache_Environment {
	/**
	 * Fixes environment in each wp-admin request
	 *
	 * @param Config  $config
	 * @param bool    $force_all_checks
	 *
	 * @throws Util_Environment_Exceptions
	 */
	public function fix_on_wpadmin_request( $config, $force_all_checks ) {
		$exs = new Util_Environment_Exceptions();

		if ( ( !defined( 'WP_CACHE' ) || !WP_CACHE ) ) {
			try {
				$this->wp_config_add_directive();
			} catch ( Util_WpFile_FilesystemOperationException $ex ) {
				$exs->push( $ex );
			}
		}

		$this->fix_folders( $config, $exs );

		if ( $config->get_boolean( 'config.check' ) || $force_all_checks ) {
			if ( $this->are_rules_present( $config ) ) {
				$this->rules_core_add( $config, $exs );
				$this->rules_cache_add( $config, $exs );
			} else {
				$this->rules_core_remove( $exs );
				$this->rules_cache_remove( $exs );
			}
		}

		// if no errors so far - check if rewrite actually works
		if ( count( $exs->exceptions() ) <= 0 ) {
			try {
				if ( $config->get_boolean( 'pgcache.enabled' ) &&
					$config->get_string( 'pgcache.engine' ) == 'file_generic' ) {
					$this->verify_file_generic_compatibility();

					if ( $config->get_boolean( 'pgcache.debug' ) )
						$this->verify_file_generic_rewrite_working();
				}
			} catch ( \Exception $ex ) {
				$exs->push( $ex );
			}
		}

		if ( count( $exs->exceptions() ) > 0 )
			throw $exs;
	}

	/**
	 * Fixes environment once event occurs
	 *
	 * @param Config  $config
	 * @param string  $event
	 * @param null|Config $old_config
	 * @throws Util_Environment_Exceptions
	 */
	public function fix_on_event( $config, $event, $old_config = null ) {
		// Schedules events
		if ( $config->get_boolean( 'pgcache.enabled' ) &&
			( $config->get_string( 'pgcache.engine' ) == 'file' ||
				$config->get_string( 'pgcache.engine' ) == 'file_generic' ) ) {
			if ( $old_config != null &&
				$config->get_integer( 'pgcache.file.gc' ) !=
				$old_config->get_integer( 'pgcache.file.gc' ) ) {
				$this->unschedule_gc();
			}

			if ( !wp_next_scheduled( 'w3_pgcache_cleanup' ) ) {
				wp_schedule_event( time(),
					'w3_pgcache_cleanup', 'w3_pgcache_cleanup' );
			}
		} else {
			$this->unschedule_gc();
		}

		// Schedule prime event
		if ( $config->get_boolean( 'pgcache.enabled' ) &&
			$config->get_boolean( 'pgcache.prime.enabled' ) ) {
			if ( $old_config != null &&
				$config->get_integer( 'pgcache.prime.interval' ) !=
				$old_config->get_integer( 'pgcache.prime.interval' ) ) {
				$this->unschedule_prime();
			}

			if ( !wp_next_scheduled( 'w3_pgcache_prime' ) ) {
				wp_schedule_event( time(),
					'w3_pgcache_prime', 'w3_pgcache_prime' );
			}
		} else {
			$this->unschedule_prime();
		}
	}

	/**
	 * Fixes environment after plugin deactivation
	 *
	 * @throws Util_Environment_Exceptions
	 */
	public function fix_after_deactivation() {
		$exs = new Util_Environment_Exceptions();

		try {
			$this->wp_config_remove_directive( $exs );
		} catch ( Util_WpFile_FilesystemOperationException $ex ) {
			$exs->push( $ex );
		}

		$this->rules_core_remove( $exs );
		$this->rules_cache_remove( $exs );

		$this->unschedule_gc();
		$this->unschedule_prime();

		if ( count( $exs->exceptions() ) > 0 )
			throw $exs;
	}

	private function are_rules_present( $c ) {
		$e = $c->get_boolean( 'pgcache.enabled' );

		return ( $e == 'file_generic' || $e == 'nginx_memcached' );
	}

	/**
	 * Returns required rules for module
	 *
	 * @param Config  $config
	 * @return array
	 */
	public function get_required_rules( $config ) {
		if ( !$this->are_rules_present( $config ) ) {
			return null;
		}

		$rewrite_rules = array();
		$pgcache_rules_core_path = Util_Rule::get_pgcache_rules_core_path();
		$rewrite_rules[] = array(
			'filename' => $pgcache_rules_core_path,
			'content' => $this->rules_core_generate( $config ),
			'priority' => 1000
		);

		$pgcache_rules_cache_path = Util_Rule::get_pgcache_rules_cache_path();
		$rewrite_rules[] = array(
			'filename' => $pgcache_rules_cache_path,
			'content' => $this->rules_cache_generate( $config )
		);

		return $rewrite_rules;
	}



	/**
	 * Fixes folders
	 *
	 * @param Config  $config
	 * @param Util_Environment_Exceptions $exs
	 */
	private function fix_folders( $config, $exs ) {
		if ( !$config->get_boolean( 'pgcache.enabled' ) )
			return;

		// folder that we delete if exists and not writeable
		if ( $config->get_string( 'pgcache.engine' ) == 'file_generic' )
			$dir = W3TC_CACHE_PAGE_ENHANCED_DIR;
		else if ( $config->get_string( 'pgcache.engine' ) != 'file' )
				$dir = W3TC_CACHE_DIR . '/page';
			else
				return;

			try{
			if ( file_exists( $dir ) && !is_writeable( $dir ) )
				Util_WpFile::delete_folder( $dir, '', $_SERVER['REQUEST_URI'] );
		} catch ( Util_WpFile_FilesystemRmdirException $ex ) {
			$exs->push( $ex );
		}
	}

	/**
	 * Checks if mode can be used
	 */
	private function verify_file_generic_compatibility() {
		$permalink_structure = get_option( 'permalink_structure' );

		if ( $permalink_structure == '' ) {
			throw new Util_Environment_Exception( 'Disk Enhanced mode ' .
				'can\'t work with "Default" permalinks structure' );
		}
	}

	/**
	 * Fixes environment for enabled pgcache
	 *
	 * @throws Util_Environment_Exceptions
	 */
	private function verify_file_generic_rewrite_working() {
		$url = get_home_url() . '/w3tc_rewrite_test' . rand();
		if ( !$this->test_rewrite( $url ) ) {
			$key = sprintf( 'w3tc_rewrite_test_result_%s', substr( md5( $url ), 0, 16 ) );
			$result = get_transient( $key );

			$home_url = get_home_url();

			$tech_message =
				( Util_Environment::is_nginx() ? 'nginx configuration file' : '.htaccess file' ) .
				' contains rules to rewrite url ' .
				$home_url . '/w3tc_rewrite_test into ' .
				$home_url . '/?w3tc_rewrite_test which, if handled by ' .
				'plugin, return "OK" message.<br/>';
			$tech_message .= 'The plugin made a request to ' .
				$home_url . '/w3tc_rewrite_test but received: <br />' .
				$result . '<br />';
			$tech_message .= 'instead of "OK" response. <br />';

			$error = '<strong>W3 Total Cache error:</strong> ' .
				'It appears Page Cache ' .
				'<acronym title="Uniform Resource Locator">URL</acronym> ' .
				'rewriting is not working. ';
			if ( Util_Environment::is_preview_mode() ) {
				$error .= ' This could be due to using Preview mode. <a href="' . $url . '">Click here</a> to manually verify its working. It should say OK. <br />';
			}

			if ( Util_Environment::is_nginx() ) {
				$error .= 'Please verify that all configuration files are ' .
					'included in the configuration file ' .
					'(and that you have reloaded / restarted nginx).';
			} else {
				$error .= 'Please verify that the server configuration ' .
					'allows .htaccess';
			}

			$error .= '<br />Unfortunately disk enhanced page caching will ' .
				'not function without custom rewrite rules. ' .
				'Please ask your server administrator for assistance. ' .
				'Also refer to <a href="' .
				admin_url( 'admin.php?page=w3tc_install' ) .
				'">the install page</a>  for the rules for your server.';

			throw new Util_Environment_Exception( $error, $tech_message );
		}
	}

	/**
	 * Perform rewrite test
	 *
	 * @param string  $url
	 * @return boolean
	 */
	private function test_rewrite( $url ) {
		$key = sprintf( 'w3tc_rewrite_test_%s', substr( md5( $url ), 0, 16 ) );
		$result = get_transient( $key );

		if ( $result === false ) {

			$response = Util_Http::get( $url );

			$result = ( !is_wp_error( $response ) && $response['response']['code'] == 200 && trim( $response['body'] ) == 'OK' );

			if ( $result ) {
				set_transient( $key, $result, 30 );
			} else {
				$key_result = sprintf( 'w3tc_rewrite_test_result_%s', substr( md5( $url ), 0, 16 ) );
				set_transient( $key_result, is_wp_error( $response )? $response->get_error_message(): implode( ' ', $response['response'] ), 30 );
			}
		}

		return $result;
	}



	/**
	 * scheduling stuff
	 */
	private function unschedule_gc() {
		if ( wp_next_scheduled( 'w3_pgcache_cleanup' ) )
			wp_clear_scheduled_hook( 'w3_pgcache_cleanup' );
	}

	private function unschedule_prime() {
		if ( wp_next_scheduled( 'w3_pgcache_prime' ) )
			wp_clear_scheduled_hook( 'w3_pgcache_prime' );
	}



	/*
	 * wp-config modification
	 */

	/**
	 * Enables WP_CACHE
	 *
	 * @throws Util_WpFile_FilesystemOperationException with S/FTP form if it can't get the required filesystem credentials
	 */
	private function wp_config_add_directive() {
		$config_path = Util_Environment::wp_config_path();

		$config_data = @file_get_contents( $config_path );
		if ( $config_data === false )
			return;

		$new_config_data = $this->wp_config_remove_from_content( $config_data );
		$new_config_data = preg_replace(
			'~<\?(php)?~',
			"\\0\r\n" . $this->wp_config_addon(),
			$new_config_data,
			1 );

		if ( $new_config_data != $config_data ) {
			try {
				Util_WpFile::write_to_file( $config_path, $new_config_data );
			} catch ( Util_WpFile_FilesystemOperationException $ex ) {
				throw new Util_WpFile_FilesystemModifyException(
					$ex->getMessage(), $ex->credentials_form(),
					'Edit file <strong>' . $config_path .
					'</strong> and add next lines:', $config_path,
					$this->wp_config_addon() );
			}
		}
		// that file was in opcache for sure and it may take time to
		// start execution of new modified now version
		$o = Dispatcher::component( 'SystemOpCache_Core' );
		$o->flush();
	}

	/**
	 * Disables WP_CACHE
	 *
	 * @throws Util_WpFile_FilesystemOperationException with S/FTP form if it can't get the required filesystem credentials
	 */
	private function wp_config_remove_directive() {
		$config_path = Util_Environment::wp_config_path();

		$config_data = @file_get_contents( $config_path );
		if ( $config_data === false )
			return;

		$new_config_data = $this->wp_config_remove_from_content( $config_data );
		if ( $new_config_data != $config_data ) {
			try {
				Util_WpFile::write_to_file( $config_path, $new_config_data );
			} catch ( Util_WpFile_FilesystemOperationException $ex ) {
				throw new Util_WpFile_FilesystemModifyException(
					$ex->getMessage(), $ex->credentials_form(),
					'Edit file <strong>' . $config_path .
					'</strong> and remove next lines:',
					$config_path,  $this->wp_config_addon() );
			}
		}
	}

	/**
	 * Returns string Addon required for plugin in wp-config
	 */
	private function wp_config_addon() {
		return "/** Enable W3 Total Cache */\r\n" .
			"define('WP_CACHE', true); // Added by W3 Total Cache\r\n";
	}

	/**
	 * Disables WP_CACHE
	 *
	 * @param string  $config_data wp-config.php content
	 * @return string
	 * @throws Util_WpFile_FilesystemOperationException with S/FTP form if it can't get the required filesystem credentials
	 */
	private function wp_config_remove_from_content( $config_data ) {
		$config_data = preg_replace(
			"~\\/\\*\\* Enable W3 Total Cache \\*\\*?\\/.*?\\/\\/ Added by W3 Total Cache(\r\n)*~s",
			'', $config_data );
		$config_data = preg_replace(
			"~(\\/\\/\\s*)?define\\s*\\(\\s*['\"]?WP_CACHE['\"]?\\s*,.*?\\)\\s*;+\\r?\\n?~is",
			'', $config_data );

		return $config_data;
	}



	/**
	 * rules core modification
	 */

	/**
	 * Writes directives to WP .htaccess / nginx.conf
	 * returns true if modifications has been made
	 */
	private function rules_core_add( $config, $exs ) {
		$path = Util_Rule::get_pgcache_rules_core_path();
		if ( $path === false )
			return;

		$original_data = @file_get_contents( $path );
		if ( $original_data === false )
			$original_data = '';

		$data = $original_data;

		if ( $has_wpsc = Util_Rule::has_rules( $data, W3TC_MARKER_BEGIN_PGCACHE_WPSC, W3TC_MARKER_END_PGCACHE_WPSC ) )
			$data = Util_Rule::erase_rules( $data, W3TC_MARKER_BEGIN_PGCACHE_WPSC, W3TC_MARKER_END_PGCACHE_WPSC );

		$rules = $this->rules_core_generate( $config );
		$rules_missing = ( strstr( Util_Rule::clean_rules( $data ), Util_Rule::clean_rules( $rules ) ) === false );


		if ( !$has_wpsc && !$rules_missing )
			return;   // modification of file not required


		$replace_start = strpos( $data, W3TC_MARKER_BEGIN_PGCACHE_CORE );
		$replace_end = strpos( $data, W3TC_MARKER_END_PGCACHE_CORE );

		if ( $replace_start !== false && $replace_end !== false && $replace_start < $replace_end ) {
			$replace_length = $replace_end - $replace_start +
				strlen( W3TC_MARKER_END_PGCACHE_CORE ) + 1;
		} else {
			$replace_start = false;
			$replace_length = 0;

			$search = array(
				W3TC_MARKER_BEGIN_BROWSERCACHE_NO404WP => 0,
				W3TC_MARKER_BEGIN_WORDPRESS => 0,
				W3TC_MARKER_END_MINIFY_CORE =>
				strlen( W3TC_MARKER_END_MINIFY_CORE ) + 1,
				W3TC_MARKER_END_BROWSERCACHE_CACHE =>
				strlen( W3TC_MARKER_END_BROWSERCACHE_CACHE ) + 1,
				W3TC_MARKER_END_PGCACHE_CACHE =>
				strlen( W3TC_MARKER_END_PGCACHE_CACHE ) + 1,
				W3TC_MARKER_END_MINIFY_CACHE =>
				strlen( W3TC_MARKER_END_MINIFY_CACHE ) + 1
			);

			foreach ( $search as $string => $length ) {
				$replace_start = strpos( $data, $string );

				if ( $replace_start !== false ) {
					$replace_start += $length;
					break;
				}
			}
		}

		if ( $replace_start !== false ) {
			$data = Util_Rule::trim_rules( substr_replace( $data, $rules,
					$replace_start, $replace_length ) );
		} else {
			$data = Util_Rule::trim_rules( $data . $rules );
		}

		try {
			Util_WpFile::write_to_file( $path, $data );
		} catch ( Util_WpFile_FilesystemOperationException $ex ) {
			if ( $has_wpsc )
				$exs->push( new Util_WpFile_FilesystemModifyException(
						$ex->getMessage(), $ex->credentials_form(),
						sprintf( __( 'Edit file <strong>%s</strong> and remove all lines between and including
								<strong>%s</strong> and <strong>%s</strong> markers.', 'w3-total-cache' )
							, $path
							, W3TC_MARKER_BEGIN_PGCACHE_WPSC
							, W3TC_MARKER_END_PGCACHE_WPSC
						), $path ) );

			if ( $rules_missing ) {
				if ( strpos( $data, W3TC_MARKER_BEGIN_PGCACHE_CORE ) !== false )
					$exs->push( new Util_WpFile_FilesystemModifyException(
							$ex->getMessage(), $ex->credentials_form(),
							sprintf( __( 'Edit file <strong>%s</strong> and replace all lines between and including
									<strong>%s</strong> and <strong>%s</strong> markers with:', 'w3-total-cache' )
								, $path
								, W3TC_MARKER_BEGIN_PGCACHE_CORE
								, W3TC_MARKER_END_PGCACHE_CORE
							), $path, $rules ) );
				else
					$exs->push( new Util_WpFile_FilesystemModifyException(
							$ex->getMessage(), $ex->credentials_form(),
							sprintf( __( 'Edit file <strong>%s</strong> and add the following rules above the WordPress
									directives:' )
								, $path
							), $path, $rules ) );
			}
			return;
		}

		Util_Rule::after_rules_modified();
	}

	/**
	 * Removes Page Cache core directives
	 *
	 * @param Util_Environment_Exceptions $exs
	 * @throws Util_WpFile_FilesystemOperationException with S/FTP form if it can't get the required filesystem credentials
	 */
	private function rules_core_remove( $exs ) {
		Util_Rule::remove_rules( $exs, Util_Rule::get_pgcache_rules_core_path(),
			W3TC_MARKER_BEGIN_PGCACHE_CORE,
			W3TC_MARKER_END_PGCACHE_CORE
		);
	}

	/**
	 * Generates rules for WP dir
	 *
	 * @param Config  $config
	 * @return string
	 */
	private function rules_core_generate( $config ) {
		switch ( true ) {
		case Util_Environment::is_apache():
		case Util_Environment::is_litespeed():
			return $this->rules_core_generate_apache( $config );

		case Util_Environment::is_nginx():
			return $this->rules_core_generate_nginx( $config );
		}

		return '';
	}

	/**
	 * Generates rules for WP dir
	 *
	 * @param Config  $config
	 * @return string
	 */
	private function rules_core_generate_apache( $config ) {
		$rewrite_base = Util_Environment::network_home_url_uri();
		$cache_dir = Util_Environment::normalize_path( W3TC_CACHE_PAGE_ENHANCED_DIR );
		$permalink_structure = get_option( 'permalink_structure' );

		$current_user = wp_get_current_user();

		/**
		 * Auto reject cookies
		 */
		$reject_cookies = array(
			'comment_author',
			'wp-postpass'
		);

		$reject_cookies[] = 'w3tc_logged_out';

		/**
		 * Reject cache for logged in users
		 * OR
		 * Reject cache for roles if any
		 */
		if ( $config->get_boolean( 'pgcache.reject.logged' ) ) {
			$reject_cookies = array_merge( $reject_cookies, array(
					'wordpress_logged_in'
				) );
		} elseif ( $config->get_boolean( 'pgcache.reject.logged_roles' ) ) {
			$new_cookies = array();
			foreach ( $config->get_array( 'pgcache.reject.roles' ) as $role ) {
				$new_cookies[] = 'w3tc_logged_' . md5( NONCE_KEY . $role );
			}
			$reject_cookies = array_merge( $reject_cookies, $new_cookies );
		}

		/**
		 * Custom config
		 */
		$reject_cookies = array_merge( $reject_cookies, $config->get_array( 'pgcache.reject.cookie' ) );
		Util_Rule::array_trim( $reject_cookies );

		$reject_user_agents = $config->get_array( 'pgcache.reject.ua' );
		if ( $config->get_boolean( 'pgcache.compatibility' ) ) {
			$reject_user_agents = array_merge( array( W3TC_POWERED_BY ), $reject_user_agents );
		}

		Util_Rule::array_trim( $reject_user_agents );

		/**
		 * Generate directives
		 */
		$env_W3TC_UA = '';
		$env_W3TC_REF = '';
		$env_W3TC_COOKIE = '';
		$env_W3TC_SSL = '';
		$env_W3TC_ENC = '';

		$rules = '';
		$rules .= W3TC_MARKER_BEGIN_PGCACHE_CORE . "\n";
		$rules .= "<IfModule mod_rewrite.c>\n";
		$rules .= "    RewriteEngine On\n";
		$rules .= "    RewriteBase " . $rewrite_base . "\n";


		if ( $config->get_boolean( 'pgcache.debug' ) ) {
			$rules .= "    RewriteRule ^(.*\\/)?w3tc_rewrite_test([0-9]+)/?$ $1?w3tc_rewrite_test=1 [L]\n";
		}


		/**
		 * Set accept query strings
		 */
		$w3tc_query_strings = $config->get_array( 'pgcache.accept.qs' );
		Util_Rule::array_trim( $w3tc_query_strings );

		if ( !empty( $w3tc_query_strings ) ) {
			$w3tc_query_strings = str_replace( ' ', '+', $w3tc_query_strings );
			$w3tc_query_strings = array_map( array( '\W3TC\Util_Environment', 'preg_quote' ), $w3tc_query_strings );

			$rules .= "    RewriteRule ^ - [E=W3TC_QUERY_STRING:%{QUERY_STRING}]\n";

			foreach ( $w3tc_query_strings as $query ) {
				$query .=  ( strpos( $query, '=' ) === false ? '=.*?' : '' );
				$rules .= "    RewriteCond %{ENV:W3TC_QUERY_STRING} ^(.*?&|)" .
					$query . "(&.*|)$ [NC]\n";
				$rules .= "    RewriteRule ^ - [E=W3TC_QUERY_STRING:%1%2]\n";
			}

			$rules .= "    RewriteCond %{ENV:W3TC_QUERY_STRING} ^&+$\n";
			$rules .= "    RewriteRule ^ - [E=W3TC_QUERY_STRING]\n";
		}

		/**
		 * Check for mobile redirect
		 */
		if ( $config->get_boolean( 'mobile.enabled' ) ) {
			$mobile_groups = $config->get_array( 'mobile.rgroups' );

			foreach ( $mobile_groups as $mobile_group => $mobile_config ) {
				$mobile_enabled = ( isset( $mobile_config['enabled'] ) ? (boolean) $mobile_config['enabled'] : false );
				$mobile_agents = ( isset( $mobile_config['agents'] ) ? (array) $mobile_config['agents'] : '' );
				$mobile_redirect = ( isset( $mobile_config['redirect'] ) ? $mobile_config['redirect'] : '' );

				if ( $mobile_enabled && count( $mobile_agents ) && $mobile_redirect ) {
					$rules .= "    RewriteCond %{HTTP_USER_AGENT} (" . implode( '|', $mobile_agents ) . ") [NC]\n";
					$rules .= "    RewriteRule .* " . $mobile_redirect . " [R,L]\n";
				}
			}
		}

		/**
		 * Check for referrer redirect
		 */
		if ( $config->get_boolean( 'referrer.enabled' ) ) {
			$referrer_groups = $config->get_array( 'referrer.rgroups' );

			foreach ( $referrer_groups as $referrer_group => $referrer_config ) {
				$referrer_enabled = ( isset( $referrer_config['enabled'] ) ? (boolean) $referrer_config['enabled'] : false );
				$referrer_referrers = ( isset( $referrer_config['referrers'] ) ? (array) $referrer_config['referrers'] : '' );
				$referrer_redirect = ( isset( $referrer_config['redirect'] ) ? $referrer_config['redirect'] : '' );

				if ( $referrer_enabled && count( $referrer_referrers ) && $referrer_redirect ) {
					$rules .= "    RewriteCond %{HTTP_COOKIE} w3tc_referrer=.*(" . implode( '|', $referrer_referrers ) . ") [NC]\n";
					$rules .= "    RewriteRule .* " . $referrer_redirect . " [R,L]\n";
				}
			}
		}

		/**
		 * Set mobile groups
		 */
		if ( $config->get_boolean( 'mobile.enabled' ) ) {
			$mobile_groups = array_reverse( $config->get_array( 'mobile.rgroups' ) );

			foreach ( $mobile_groups as $mobile_group => $mobile_config ) {
				$mobile_enabled = ( isset( $mobile_config['enabled'] ) ? (boolean) $mobile_config['enabled'] : false );
				$mobile_agents = ( isset( $mobile_config['agents'] ) ? (array) $mobile_config['agents'] : '' );
				$mobile_redirect = ( isset( $mobile_config['redirect'] ) ? $mobile_config['redirect'] : '' );

				if ( $mobile_enabled && count( $mobile_agents ) && !$mobile_redirect ) {
					$rules .= "    RewriteCond %{HTTP_USER_AGENT} (" . implode( '|', $mobile_agents ) . ") [NC]\n";
					$rules .= "    RewriteRule .* - [E=W3TC_UA:_" . $mobile_group . "]\n";
					$env_W3TC_UA = '%{ENV:W3TC_UA}';
				}
			}
		}

		/**
		 * Set referrer groups
		 */
		if ( $config->get_boolean( 'referrer.enabled' ) ) {
			$referrer_groups = array_reverse( $config->get_array( 'referrer.rgroups' ) );

			foreach ( $referrer_groups as $referrer_group => $referrer_config ) {
				$referrer_enabled = ( isset( $referrer_config['enabled'] ) ? (boolean) $referrer_config['enabled'] : false );
				$referrer_referrers = ( isset( $referrer_config['referrers'] ) ? (array) $referrer_config['referrers'] : '' );
				$referrer_redirect = ( isset( $referrer_config['redirect'] ) ? $referrer_config['redirect'] : '' );

				if ( $referrer_enabled && count( $referrer_referrers ) && !$referrer_redirect ) {
					$rules .= "    RewriteCond %{HTTP_COOKIE} w3tc_referrer=.*(" . implode( '|', $referrer_referrers ) . ") [NC]\n";
					$rules .= "    RewriteRule .* - [E=W3TC_REF:_" . $referrer_group . "]\n";
					$env_W3TC_REF = '%{ENV:W3TC_REF}';
				}
			}
		}

		/**
		 * Set cookie group
		 */
		if ( $config->get_boolean( 'pgcache.cookiegroups.enabled' ) ) {
			$cookie_groups = $config->get_array( 'pgcache.cookiegroups.groups' );

			foreach ( $cookie_groups as $group_name => $g ) {
				if ( isset( $g['enabled'] ) && $g['enabled'] ) {
					$cookies = array();
					foreach ($g['cookies'] as $cookie ) {
						$cookie = trim( $cookie );
						if ( !empty( $cookie ) ) {
							$cookie = str_replace( '+', ' ', $cookie );
							$cookie = Util_Environment::preg_quote( $cookie );
							if ( strpos( $cookie, '=') === false )
								$cookie .= '=.*';
							$cookies[] = $cookie;
						}
					}

					if ( count( $cookies ) > 0 ) {
						$cookies_regexp = '^(.*;\s*)?(' . implode( '|', $cookies ) . ')(\s*;.*)?$';
						$rules .= "    RewriteCond %{HTTP_COOKIE} $cookies_regexp [NC]\n";
						$rules .= "    RewriteRule .* - [E=W3TC_COOKIE:_" . $group_name . "]\n";
						$env_W3TC_COOKIE = '%{ENV:W3TC_COOKIE}';
					}
				}
			}
		}

		/**
		 * Set HTTPS
		 */
		if ( $config->get_boolean( 'pgcache.cache.ssl' ) ) {
			$rules .= "    RewriteCond %{HTTPS} =on\n";
			$rules .= "    RewriteRule .* - [E=W3TC_SSL:_ssl]\n";
			$rules .= "    RewriteCond %{SERVER_PORT} =443\n";
			$rules .= "    RewriteRule .* - [E=W3TC_SSL:_ssl]\n";
			$rules .= "    RewriteCond %{HTTP:X-Forwarded-Proto} =https [NC]\n";
			$rules .= "    RewriteRule .* - [E=W3TC_SSL:_ssl]\n";
			$env_W3TC_SSL = '%{ENV:W3TC_SSL}';
		}

		$cache_path = str_replace( Util_Environment::document_root(), '', $cache_dir );

		/**
		 * Set Accept-Encoding
		 */
		if ( $config->get_boolean( 'browsercache.enabled' ) && $config->get_boolean( 'browsercache.html.brotli' ) ) {
			$rules .= "    RewriteCond %{HTTP:Accept-Encoding} br\n";
			$rules .= "    RewriteRule .* - [E=W3TC_ENC:_br]\n";
			$env_W3TC_ENC = '%{ENV:W3TC_ENC}';
		} else if ( $config->get_boolean( 'browsercache.enabled' ) && $config->get_boolean( 'browsercache.html.compression' ) ) {
			$rules .= "    RewriteCond %{HTTP:Accept-Encoding} gzip\n";
			$rules .= "    RewriteRule .* - [E=W3TC_ENC:_gzip]\n";
			$env_W3TC_ENC = '%{ENV:W3TC_ENC}';
		}
		$rules .= "    RewriteCond %{HTTP_COOKIE} w3tc_preview [NC]\n";
		$rules .= "    RewriteRule .* - [E=W3TC_PREVIEW:_preview]\n";
		$env_W3TC_PREVIEW = '%{ENV:W3TC_PREVIEW}';

		$use_cache_rules = '';
		/**
		 * Don't accept POSTs
		 */
		$use_cache_rules .= "    RewriteCond %{REQUEST_METHOD} !=POST\n";

		/**
		 * Query string should be empty
		 */
		$use_cache_rules .= empty( $w3tc_query_strings ) ?
			"    RewriteCond %{QUERY_STRING} =\"\"\n" :
			"    RewriteCond %{ENV:W3TC_QUERY_STRING} =\"\"\n";

		/**
		 * Check permalink structure trailing slash
		 */
		if ( substr( $permalink_structure, -1 ) == '/' ) {
			$use_cache_rules .= "    RewriteCond %{REQUEST_URI} \\/$\n";
		}

		/**
		 * Check for rejected cookies
		 */
		$use_cache_rules .= "    RewriteCond %{HTTP_COOKIE} !(" . implode( '|',
			array_map( array( '\W3TC\Util_Environment', 'preg_quote' ), $reject_cookies ) ) . ") [NC]\n";

		/**
		 * Check for rejected user agents
		 */
		if ( count( $reject_user_agents ) ) {
			$use_cache_rules .= "    RewriteCond %{HTTP_USER_AGENT} !(" .
				implode( '|',
				array_map( array( '\W3TC\Util_Environment', 'preg_quote' ), $reject_user_agents ) ) . ") [NC]\n";
		}

		/**
		 * Make final rewrites for specific files
		 */
		$uri_prefix =  $cache_path . '/%{HTTP_HOST}/%{REQUEST_URI}/' .
			'_index' . $env_W3TC_UA . $env_W3TC_REF . $env_W3TC_COOKIE .
			$env_W3TC_SSL . $env_W3TC_PREVIEW;
		$switch = " -" . ( $config->get_boolean( 'pgcache.file.nfs' ) ? 'F' : 'f' );

		$document_root = Util_Rule::apache_docroot_variable();

		// write rule to rewrite to .html/.xml file
		$exts = array( '.html' );
		if ($config->get_boolean('pgcache.cache.nginx_handle_xml'))
			$exts[] = '.xml';

		foreach ( $exts as $ext ) {
			$rules .= $use_cache_rules;
			$rules .= "    RewriteCond \"" . $document_root . $uri_prefix . $ext .
				$env_W3TC_ENC . "\"" . $switch . "\n";
			$rules .= "    RewriteRule .* \"" . $uri_prefix . $ext .
				$env_W3TC_ENC . "\" [L]\n";
		}

		$rules .= "</IfModule>\n";

		$rules .= W3TC_MARKER_END_PGCACHE_CORE . "\n";

		return $rules;
	}

	/**
	 * Generates rules for WP dir
	 *
	 * @param Config  $config
	 * @return string
	 */
	private function rules_core_generate_nginx( $config ) {
		$is_network = Util_Environment::is_wpmu();

		$cache_dir = Util_Environment::normalize_path( W3TC_CACHE_PAGE_ENHANCED_DIR );
		$permalink_structure = get_option( 'permalink_structure' );
		$pgcache_engine = $config->get_string( 'pgcache.engine' );

		/**
		 * Auto reject cookies
		 */
		$reject_cookies = array(
			'comment_author',
			'wp-postpass'
		);

		if ( $pgcache_engine == 'file_generic' ) {
			$reject_cookies[] = 'w3tc_logged_out';
		}

		/**
		 * Reject cache for logged in users
		 * OR
		 * Reject cache for roles if any
		 */
		if ( $config->get_boolean( 'pgcache.reject.logged' ) ) {
			$reject_cookies = array_merge( $reject_cookies, array(
					'wordpress_logged_in'
				) );
		} elseif ( $config->get_boolean( 'pgcache.reject.logged_roles' ) ) {
			$new_cookies = array();
			foreach ( $config->get_array( 'pgcache.reject.roles' ) as $role ) {
				$new_cookies[] = 'w3tc_logged_' . md5( NONCE_KEY . $role );
			}
			$reject_cookies = array_merge( $reject_cookies, $new_cookies );
		}

		/**
		 * Custom config
		 */
		$reject_cookies = array_merge( $reject_cookies,
			$config->get_array( 'pgcache.reject.cookie' ) );
		Util_Rule::array_trim( $reject_cookies );

		$reject_user_agents = $config->get_array( 'pgcache.reject.ua' );
		if ( $config->get_boolean( 'pgcache.compatibility' ) ) {
			$reject_user_agents = array_merge( array( W3TC_POWERED_BY ),
				$reject_user_agents );
		}
		Util_Rule::array_trim( $reject_user_agents );

		/**
		 * Generate rules
		 */
		$env_w3tc_ua = '';
		$env_w3tc_ref = '';
		$env_w3tc_cookie = '';
		$env_w3tc_ssl = '';
		$env_w3tc_ext = '';
		$env_w3tc_enc = '';
		$env_request_uri = '$request_uri';

		$rules = '';
		$rules .= W3TC_MARKER_BEGIN_PGCACHE_CORE . "\n";
		if ( $config->get_boolean( 'pgcache.debug' ) ) {
			$rules .= "rewrite ^(.*\\/)?w3tc_rewrite_test([0-9]+)/?$ $1?w3tc_rewrite_test=1 last;\n";
		}

		/**
		 * Set accept query strings
		 */
		$w3tc_query_strings = $config->get_array( 'pgcache.accept.qs' );
		Util_Rule::array_trim( $w3tc_query_strings );

		if ( !empty( $w3tc_query_strings ) ) {
		   $w3tc_query_strings = str_replace( ' ', '+', $w3tc_query_strings );
		   $w3tc_query_strings = array_map( array( '\W3TC\Util_Environment', 'preg_quote' ), $w3tc_query_strings );

			$rules .= "set \$w3tc_query_string \$query_string;\n";

			foreach ( $w3tc_query_strings as $query ) {
				$query .=  ( strpos( $query, '=' ) === false ? '=.*?' : '' );
				$rules .= "if (\$w3tc_query_string ~* \"^(.*?&|)" . $query . "(&.*|)$\") {\n";
				$rules .= "    set \$w3tc_query_string $1$2;\n";
				$rules .= "}\n";
			}

			$rules .= "if (\$w3tc_query_string ~ ^[?&]+$) {\n";
			$rules .= "    set \$w3tc_query_string \"\";\n";
			$rules .= "}\n";

			$rules .= "set \$w3tc_request_uri \$request_uri;\n";
			$rules .= "if (\$w3tc_request_uri ~* \"^([^?]+)\?\") {\n";
			$rules .= "    set \$w3tc_request_uri \$1;\n";
			$rules .= "}\n";
			$env_request_uri = '$w3tc_request_uri';
		}

		/**
		 * Check for mobile redirect
		 */
		if ( $config->get_boolean( 'mobile.enabled' ) ) {
			$mobile_groups = $config->get_array( 'mobile.rgroups' );

			foreach ( $mobile_groups as $mobile_group => $mobile_config ) {
				$mobile_enabled = ( isset( $mobile_config['enabled'] ) ?
					(boolean) $mobile_config['enabled'] : false );
				$mobile_agents = ( isset( $mobile_config['agents'] ) ?
					(array) $mobile_config['agents'] : '' );
				$mobile_redirect = ( isset( $mobile_config['redirect'] ) ?
					$mobile_config['redirect'] : '' );

				if ( $mobile_enabled && count( $mobile_agents ) && $mobile_redirect ) {
					$rules .= "if (\$http_user_agent ~* \"(" . implode( '|',
						$mobile_agents ) . ")\") {\n";
					$rules .= "    rewrite .* " . $mobile_redirect . " last;\n";
					$rules .= "}\n";
				}
			}
		}

		/**
		 * Check for referrer redirect
		 */
		if ( $config->get_boolean( 'referrer.enabled' ) ) {
			$referrer_groups = $config->get_array( 'referrer.rgroups' );

			foreach ( $referrer_groups as $referrer_group => $referrer_config ) {
				$referrer_enabled = ( isset( $referrer_config['enabled'] ) ?
					(boolean) $referrer_config['enabled'] : false );
				$referrer_referrers = ( isset( $referrer_config['referrers'] ) ?
					(array) $referrer_config['referrers'] : '' );
				$referrer_redirect = ( isset( $referrer_config['redirect'] ) ?
					$referrer_config['redirect'] : '' );

				if ( $referrer_enabled && count( $referrer_referrers ) &&
					$referrer_redirect ) {
					$rules .= "if (\$http_cookie ~* \"w3tc_referrer=.*(" .
						implode( '|', $referrer_referrers ) . ")\") {\n";
					$rules .= "    rewrite .* " . $referrer_redirect . " last;\n";
					$rules .= "}\n";
				}
			}
		}

		/**
		 * Don't accept POSTs
		 */
		$rules .= "set \$w3tc_rewrite 1;\n";
		$rules .= "if (\$request_method = POST) {\n";
		$rules .= "    set \$w3tc_rewrite 0;\n";
		$rules .= "}\n";

		/**
		 * Query string should be empty
		 */
		$querystring_variable = ( empty( $w3tc_query_strings ) ?
			'$query_string' : '$w3tc_query_string' );

		$rules .= "if (" . $querystring_variable . " != \"\") {\n";
		$rules .= "    set \$w3tc_rewrite 0;\n";
		$rules .= "}\n";

		/**
		 * Check permalink structure trailing slash
		 * and allow WordPress to redirect for non-slash URIs
		 */
		if ( $pgcache_engine == 'file_generic' ) {
			if ( substr( $permalink_structure, -1 ) == '/' ) {
				$rules .= "if ($env_request_uri !~ \\/$) {\n";
				$rules .= "    set \$w3tc_rewrite 0;\n";
				$rules .= "}\n";
			}
		}

		/**
		 * Check for rejected cookies
		 */
		$rules .= "if (\$http_cookie ~* \"(" . implode( '|',
			array_map( array( '\W3TC\Util_Environment', 'preg_quote' ), $reject_cookies ) ) . ")\") {\n";
		$rules .= "    set \$w3tc_rewrite 0;\n";
		$rules .= "}\n";

		/**
		 * Check for rejected user agents
		 */
		if ( count( $reject_user_agents ) ) {
			$rules .= "if (\$http_user_agent ~* \"(" . implode( '|',
				array_map( array( '\W3TC\Util_Environment', 'preg_quote' ), $reject_user_agents ) ) . ")\") {\n";
			$rules .= "    set \$w3tc_rewrite 0;\n";
			$rules .= "}\n";
		}

		/**
		 * Check mobile groups
		 */
		if ( $config->get_boolean( 'mobile.enabled' ) ) {
			$mobile_groups = array_reverse( $config->get_array( 'mobile.rgroups' ) );
			$set_ua_var = true;

			foreach ( $mobile_groups as $mobile_group => $mobile_config ) {
				$mobile_enabled = ( isset( $mobile_config['enabled'] ) ?
					(boolean) $mobile_config['enabled'] : false );
				$mobile_agents = ( isset( $mobile_config['agents'] ) ?
					(array) $mobile_config['agents'] : '' );
				$mobile_redirect = ( isset( $mobile_config['redirect'] ) ?
					$mobile_config['redirect'] : '' );

				if ( $mobile_enabled && count( $mobile_agents ) &&
					!$mobile_redirect ) {
					if ( $set_ua_var ) {
						$rules .= "set \$w3tc_ua \"\";\n";
						$set_ua_var = false;
					}
					$rules .= "if (\$http_user_agent ~* \"(" .
						implode( '|', $mobile_agents ) . ")\") {\n";
					$rules .= "    set \$w3tc_ua _" . $mobile_group . ";\n";
					$rules .= "}\n";

					$env_w3tc_ua = "\$w3tc_ua";
				}
			}
		}

		/**
		 * Check for preview cookie
		 */
		$rules .= "set \$w3tc_preview \"\";\n";
		$rules .= "if (\$http_cookie ~* \"(w3tc_preview)\") {\n";
		$rules .= "    set \$w3tc_preview _preview;\n";
		$rules .= "}\n";
		$env_w3tc_preview = "\$w3tc_preview";

		/**
		 * Check referrer groups
		 */
		if ( $config->get_boolean( 'referrer.enabled' ) ) {
			$referrer_groups = array_reverse( $config->get_array( 'referrer.rgroups' ) );
			$set_ref_var = true;
			foreach ( $referrer_groups as $referrer_group => $referrer_config ) {
				$referrer_enabled = ( isset( $referrer_config['enabled'] ) ?
					(boolean) $referrer_config['enabled'] : false );
				$referrer_referrers = ( isset( $referrer_config['referrers'] ) ?
					(array) $referrer_config['referrers'] : '' );
				$referrer_redirect = ( isset( $referrer_config['redirect'] ) ?
					$referrer_config['redirect'] : '' );

				if ( $referrer_enabled && count( $referrer_referrers ) &&
					!$referrer_redirect ) {
					if ( $set_ref_var ) {
						$rules .= "set \$w3tc_ref \"\";\n";
						$set_ref_var = false;
					}
					$rules .= "if (\$http_cookie ~* \"w3tc_referrer=.*(" .
						implode( '|', $referrer_referrers ) . ")\") {\n";
					$rules .= "    set \$w3tc_ref _" . $referrer_group . ";\n";
					$rules .= "}\n";

					$env_w3tc_ref = "\$w3tc_ref";
				}
			}
		}

		/**
		 * Set cookie group
		 */
		if ( $config->get_boolean( 'pgcache.cookiegroups.enabled' ) ) {
			$cookie_groups = $config->get_array( 'pgcache.cookiegroups.groups' );
			$set_cookie_var = true;

			foreach ( $cookie_groups as $group_name => $g ) {
				if ( isset( $g['enabled'] ) && $g['enabled'] ) {
					$cookies = array();
					foreach ($g['cookies'] as $cookie ) {
						$cookie = trim( $cookie );
						if ( !empty( $cookie ) ) {
							$cookie = str_replace( '+', ' ', $cookie );
							$cookie = Util_Environment::preg_quote( $cookie );
							if ( strpos( $cookie, '=') === false )
								$cookie .= '=.*';
							$cookies[] = $cookie;
						}
					}

					if ( count( $cookies ) > 0 ) {
						$cookies_regexp = '"^(.*;)?(' . implode( '|', $cookies ) . ')(;.*)?$"';

						if ( $set_cookie_var ) {
							$rules .= "set \$w3tc_cookie \"\";\n";
							$set_cookie_var = false;
						}
						$rules .= "if (\$http_cookie ~* $cookies_regexp) {\n";
						$rules .= "    set \$w3tc_cookie _" . $group_name . ";\n";
						$rules .= "}\n";

						$env_w3tc_cookie = "\$w3tc_cookie";
					}
				}
			}
		}

		if ( $config->get_boolean( 'pgcache.cache.ssl' ) ) {
			$rules .= "set \$w3tc_ssl \"\";\n";

			$rules .= "if (\$scheme = https) {\n";
			$rules .= "    set \$w3tc_ssl _ssl;\n";
			$rules .= "}\n";
			$rules .= "if (\$http_x_forwarded_proto = 'https') {\n";
			$rules .= "    set \$w3tc_ssl _ssl;\n";
			$rules .= "}\n";

			$env_w3tc_ssl = '$w3tc_ssl';
		}

		if ( $config->get_boolean( 'browsercache.enabled' ) &&
		     $config->get_boolean( 'browsercache.html.brotli' ) ) {
			$rules .= "set \$w3tc_enc \"\";\n";

			$rules .= "if (\$http_accept_encoding ~ br) {\n";
			$rules .= "    set \$w3tc_enc _br;\n";
			$rules .= "}\n";

			$env_w3tc_enc = '$w3tc_enc';
		}

		if ( $config->get_boolean( 'browsercache.enabled' ) &&
			$config->get_boolean( 'browsercache.html.compression' ) ) {
			$rules .= "set \$w3tc_enc \"\";\n";

			$rules .= "if (\$http_accept_encoding ~ gzip) {\n";
			$rules .= "    set \$w3tc_enc _gzip;\n";
			$rules .= "}\n";

			$env_w3tc_enc = '$w3tc_enc';
		}

		$key_postfix = $env_w3tc_ua . $env_w3tc_ref . $env_w3tc_cookie .
			$env_w3tc_ssl . $env_w3tc_preview;

		if ( $pgcache_engine == 'file_generic' ) {
			$rules .= $this->for_file_generic( $config, $cache_dir,
				$env_request_uri, $key_postfix, $env_w3tc_enc );
		} elseif ( $pgcache_engine == 'nginx_memcached' ) {
			$rules .= $this->for_nginx_memcached( $config, $cache_dir,
				$env_request_uri, $key_postfix, $env_w3tc_enc );
		}

		$rules .= W3TC_MARKER_END_PGCACHE_CORE . "\n";

		return $rules;
	}



	private function for_file_generic( $config, $cache_dir, $env_request_uri,
			$key_postfix, $env_w3tc_enc ) {
		$rules = '';

		$cache_path = str_replace( Util_Environment::document_root(), '',
			$cache_dir );
		$uri_prefix = $cache_path . "/\$http_host/$env_request_uri/_index" .
			$key_postfix;

		if ( !$config->get_boolean( 'pgcache.cache.nginx_handle_xml' ) ) {
			$env_w3tc_ext = '.html';

			$rules .= 'if (!-f "$document_root' . $uri_prefix . '.html' .
				$env_w3tc_enc . '") {' . "\n";
			$rules .= '  set $w3tc_rewrite 0;' . "\n";
			$rules .= "}\n";
		} else {
			$env_w3tc_ext = '$w3tc_ext';

			$rules .= 'set $w3tc_ext "";' . "\n";
			$rules .= 'if (-f "$document_root' . $uri_prefix . '.html' .
				$env_w3tc_enc . '") {' . "\n";
			$rules .= '  set $w3tc_ext .html;' . "\n";
			$rules .= "}\n";

			$rules .= 'if (-f "$document_root' . $uri_prefix . '.xml' .
				$env_w3tc_enc . '") {' . "\n";
			$rules .= '    set $w3tc_ext .xml;' . "\n";
			$rules .= "}\n";

			$rules .= 'if ($w3tc_ext = "") {' . "\n";
			$rules .= '  set $w3tc_rewrite 0;' . "\n";
			$rules .= "}\n";
		}

		$rules .= 'if ($w3tc_rewrite = 1) {' . "\n";
		$rules .= '    rewrite .* "' . $uri_prefix . $env_w3tc_ext . $env_w3tc_enc .
			'" last;' . "\n";
		$rules .= "}\n";

		return $rules;
	}



	private function for_nginx_memcached( $config, $cache_dir, $env_request_uri,
			$key_postfix, $env_w3tc_enc ) {
		$rules =  "set \$request_uri_noslash $env_request_uri;\n";
		$rules .= "if ($env_request_uri ~ \"(.*?)(/+)$\") {\n";
		$rules .= '    set $request_uri_noslash $1;' . "\n";
		$rules .= "}\n";

		$cache_path = str_replace( Util_Environment::document_root(), '',
			$cache_dir );

		$rules .= 'location ~ ".*(?<!php)$" {' . "\n";
        $rules .= '  set $memcached_key "$http_host$request_uri_noslash/' .
        	$key_postfix . $env_w3tc_enc . '";' . "\n";

		if ( $config->get_boolean( 'browsercache.enabled' ) &&
			$config->get_boolean( 'browsercache.html.compression' ) ) {
        	$rules .= '  memcached_gzip_flag 65536;' . "\n";
       	}

        $rules .= '  default_type text/html;' . "\n";
        $rules .= '  if ($w3tc_rewrite = 1) {' . "\n";
        $rules .= '    memcached_pass localhost:11211;' . "\n";
		$rules .= "  }\n";
        $rules .= '  error_page     404 502 504 = @fallback;' . "\n";
		$rules .= "}\n";

        $rules .= 'location @fallback {' . "\n";
        $rules .= '  try_files $uri $uri/ $uri.html /index.php?$args;' . "\n";
		$rules .= "}\n";

		return $rules;
	}



	/*
	 * cache rules
	 */

	/**
	 * Writes directives to file cache .htaccess
	 * Throws exception on error
	 *
	 * @param Config  $config
	 * @param Util_Environment_Exceptions $exs
	 */
	private function rules_cache_add( $config, $exs ) {
		Util_Rule::add_rules( $exs,
			Util_Rule::get_pgcache_rules_cache_path(),
			$this->rules_cache_generate( $config ),
			W3TC_MARKER_BEGIN_PGCACHE_CACHE,
			W3TC_MARKER_END_PGCACHE_CACHE,
			array(
				W3TC_MARKER_BEGIN_BROWSERCACHE_CACHE => 0,
				W3TC_MARKER_BEGIN_MINIFY_CORE => 0,
				W3TC_MARKER_BEGIN_PGCACHE_CORE => 0,
				W3TC_MARKER_BEGIN_BROWSERCACHE_NO404WP => 0,
				W3TC_MARKER_BEGIN_WORDPRESS => 0,
				W3TC_MARKER_END_MINIFY_CACHE => strlen( W3TC_MARKER_END_MINIFY_CACHE ) + 1
			)
		);
	}

	/**
	 * Removes Page Cache cache directives
	 *
	 * @param Util_Environment_Exceptions $exs
	 * @throws Util_WpFile_FilesystemOperationException with S/FTP form if it can't get the required filesystem credentials
	 */
	private function rules_cache_remove( $exs ) {
		// apache's cache files are not used when core rules disabled
		if ( !Util_Environment::is_nginx() )
			return;

		Util_Rule::remove_rules( $exs,
			Util_Rule::get_pgcache_rules_cache_path(),
			W3TC_MARKER_BEGIN_PGCACHE_CACHE,
			W3TC_MARKER_END_PGCACHE_CACHE );
	}

	/**
	 * Generates directives for file cache dir
	 *
	 * @param Config  $config
	 * @return string
	 */
	public function rules_cache_generate( $config ) {
		switch ( true ) {
		case Util_Environment::is_apache():
		case Util_Environment::is_litespeed():
			return $this->rules_cache_generate_apache( $config );

		case Util_Environment::is_nginx():
			return $this->rules_cache_generate_nginx( $config );
		}

		return '';
	}


	/**
	 * Generates directives for file cache dir
	 *
	 * @param Config  $config
	 * @return string
	 */
	private function rules_cache_generate_apache( $config ) {
		$charset = get_option( 'blog_charset' );
		$pingback_url = get_bloginfo( 'pingback_url' );

		$browsercache = $config->get_boolean( 'browsercache.enabled' );
		$brotli = ( $browsercache && $config->get_boolean( 'browsercache.html.brotli' ) );
		$compression = ( $browsercache && $config->get_boolean( 'browsercache.html.compression' ) );
		$expires = ( $browsercache && $config->get_boolean( 'browsercache.html.expires' ) );
		$lifetime = ( $browsercache ? $config->get_integer( 'browsercache.html.lifetime' ) : 0 );
		$cache_control = ( $browsercache && $config->get_boolean( 'browsercache.html.cache.control' ) );
		$etag = ( $browsercache && $config->get_integer( 'browsercache.html.etag' ) );
		$w3tc = ( $browsercache && $config->get_integer( 'browsercache.html.w3tc' ) );
		$compatibility = $config->get_boolean( 'pgcache.compatibility' );

		$rules = '';
		$rules .= W3TC_MARKER_BEGIN_PGCACHE_CACHE . "\n";
		if ( $compatibility ) {
			$rules .= "Options -MultiViews\n";

			// allow to read files by apache if they are blocked at some level above
			$rules .= "<Files ~ \"\.(html|html_gzip|html_br|xml|xml_gzip|xml_br)$\">\n";

			if ( version_compare( Util_Environment::get_server_version(), '2.4', '>=' ) ) {
				$rules .= "  Require all granted\n";
			} else {
				$rules .= "  Order Allow,Deny\n";
				$rules .= "  Allow from all\n";
			}

			$rules .= "</Files>\n";

			if ( !$etag ) {
				$rules .= "FileETag None\n";
			}
		}
		if ( $config->get_boolean( 'pgcache.file.nfs' ) ) {
			$rules .= "EnableSendfile Off \n";
		}

		if ( !$config->get_boolean( 'pgcache.remove_charset' ) ) {
			$rules .= "AddDefaultCharset " . ( $charset ? $charset : 'utf-8' ) . "\n";
		}

		if ( $etag ) {
			$rules .= "FileETag MTime Size\n";
		}

		if ( $brotli ) {
			$rules .= "<IfModule mod_mime.c>\n";
			$rules .= "    AddType text/html .html_br\n";
			$rules .= "    AddEncoding br .html_br\n";
			$rules .= "    AddType text/xml .xml_br\n";
			$rules .= "    AddEncoding br .xml_br\n";
			$rules .= "</IfModule>\n";
			$rules .= "<IfModule mod_setenvif.c>\n";
			$rules .= "    SetEnvIfNoCase Request_URI \\.html_br$ no-brotli\n";
			$rules .= "    SetEnvIfNoCase Request_URI \\.xml_br$ no-brotli\n";
			$rules .= "</IfModule>\n";
		}

		if ( $compression ) {
			$rules .= "<IfModule mod_mime.c>\n";
			$rules .= "    AddType text/html .html_gzip\n";
			$rules .= "    AddEncoding gzip .html_gzip\n";
			$rules .= "    AddType text/xml .xml_gzip\n";
			$rules .= "    AddEncoding gzip .xml_gzip\n";
			$rules .= "</IfModule>\n";
			$rules .= "<IfModule mod_setenvif.c>\n";
			$rules .= "    SetEnvIfNoCase Request_URI \\.html_gzip$ no-gzip\n";
			$rules .= "    SetEnvIfNoCase Request_URI \\.xml_gzip$ no-gzip\n";
			$rules .= "</IfModule>\n";
		}

		if ( $expires ) {
			$rules .= "<IfModule mod_expires.c>\n";
			$rules .= "    ExpiresActive On\n";
			$rules .= "    ExpiresByType text/html M" . $lifetime . "\n";
			$rules .= "</IfModule>\n";
		}

		$header_rules = '';

		if ( $compatibility ) {
			$header_rules .= "    Header set X-Pingback \"" . $pingback_url . "\"\n";
		}

		if ( $w3tc ) {
			$header_rules .= "    Header set X-Powered-By \"" .
				Util_Environment::w3tc_header() . "\"\n";
		}

		if ( $expires ) {
			$header_rules .= "    Header set Vary \"Accept-Encoding, Cookie\"\n";
		}

		$set_last_modified = $config->get_boolean( 'browsercache.html.last_modified' );

		if ( !$set_last_modified && $config->get_boolean( 'browsercache.enabled' ) ) {
			$header_rules .= "    Header unset Last-Modified\n";
		}

		if ( $cache_control ) {
			$cache_policy = $config->get_string( 'browsercache.html.cache.policy' );

			switch ( $cache_policy ) {
			case 'cache':
				$header_rules .= "    Header set Pragma \"public\"\n";
				$header_rules .= "    Header set Cache-Control \"public\"\n";
				break;

			case 'cache_public_maxage':
				$header_rules .= "    Header set Pragma \"public\"\n";

				if ( $expires ) {
					$header_rules .= "    Header append Cache-Control \"public\"\n";
				} else {
					$header_rules .= "    Header set Cache-Control \"max-age=" . $lifetime . ", public\"\n";
				}
				break;

			case 'cache_validation':
				$header_rules .= "    Header set Pragma \"public\"\n";
				$header_rules .= "    Header set Cache-Control \"public, must-revalidate, proxy-revalidate\"\n";
				break;

			case 'cache_noproxy':
				$header_rules .= "    Header set Pragma \"public\"\n";
				$header_rules .= "    Header set Cache-Control \"private, must-revalidate\"\n";
				break;

			case 'cache_maxage':
				$header_rules .= "    Header set Pragma \"public\"\n";

				if ( $expires ) {
					$header_rules .= "    Header append Cache-Control \"public, must-revalidate, proxy-revalidate\"\n";
				} else {
					$header_rules .= "    Header set Cache-Control \"max-age=" . $lifetime . ", public, must-revalidate, proxy-revalidate\"\n";
				}
				break;

			case 'no_cache':
				$header_rules .= "    Header set Pragma \"no-cache\"\n";
				$header_rules .= "    Header set Cache-Control \"max-age=0, private, no-store, no-cache, must-revalidate\"\n";
				break;
			}
		}

		if ( strlen( $header_rules ) > 0 ) {
			$rules .= "<IfModule mod_headers.c>\n";
			$rules .= $header_rules;
			$rules .= "</IfModule>\n";
		}

		$rules .= W3TC_MARKER_END_PGCACHE_CACHE . "\n";

		return $rules;
	}

	/**
	 * Generates directives for file cache dir
	 *
	 * @param Config  $config
	 * @return string
	 */
	private function rules_cache_generate_nginx( $config ) {
		if ( $config->get_string( 'pgcache.engine') != 'file_generic' ) {
			return '';
		}

		$cache_root = Util_Environment::normalize_path( W3TC_CACHE_PAGE_ENHANCED_DIR );
		$cache_dir = rtrim( str_replace( Util_Environment::document_root(), '', $cache_root ), '/' );

		if ( Util_Environment::is_wpmu() ) {
			$cache_dir = preg_replace( '~/w3tc.*?/~', '/w3tc.*?/', $cache_dir, 1 );
		}

		$browsercache = $config->get_boolean( 'browsercache.enabled' );
		$brotli = ( $browsercache && $config->get_boolean( 'browsercache.html.brotli' ) );
		$compression = ( $browsercache && $config->get_boolean( 'browsercache.html.compression' ) );
		$expires = ( $browsercache && $config->get_boolean( 'browsercache.html.expires' ) );
		$lifetime = ( $browsercache ? $config->get_integer( 'browsercache.html.lifetime' ) : 0 );
		$cache_control = ( $browsercache && $config->get_boolean( 'browsercache.html.cache.control' ) );
		$w3tc = ( $browsercache && $config->get_integer( 'browsercache.html.w3tc' ) );
		$hsts = ( $browsercache && $config->get_boolean( 'browsercache.hsts' ) );

		$common_rules = '';

		if ( $expires ) {
			$common_rules .= "    expires modified " . $lifetime . "s;\n";
		}

		if ( $w3tc ) {
			$common_rules .= "    add_header X-Powered-By \"" .
				Util_Environment::w3tc_header() . "\";\n";
		}

		if ( $hsts ) {
			$common_rules .= " add_header Strict-Transport-Security \"max-age=31536000; preload\";\n";
		}
		if ( $expires ) {
			$common_rules .= "    add_header Vary \"Accept-Encoding, Cookie\";\n";
		}

		if ( $cache_control ) {
			$cache_policy = $config->get_string( 'browsercache.html.cache.policy' );

			switch ( $cache_policy ) {
			case 'cache':
				$common_rules .= "    add_header Pragma \"public\";\n";
				$common_rules .= "    add_header Cache-Control \"public\";\n";
				break;

			case 'cache_public_maxage':
				$common_rules .= "    add_header Pragma \"public\";\n";

				if ( $expires ) {
					$common_rules .= "    add_header Cache-Control \"public\";\n";
				} else {
					$common_rules .= "    add_header Cache-Control \"max-age=" . $lifetime . ", public\";\n";
				}
				break;

			case 'cache_validation':
				$common_rules .= "    add_header Pragma \"public\";\n";
				$common_rules .= "    add_header Cache-Control \"public, must-revalidate, proxy-revalidate\";\n";
				break;

			case 'cache_noproxy':
				$common_rules .= "    add_header Pragma \"public\";\n";
				$common_rules .= "    add_header Cache-Control \"private, must-revalidate\";\n";
				break;

			case 'cache_maxage':
				$common_rules .= "    add_header Pragma \"public\";\n";

				if ( $expires ) {
					$common_rules .= "    add_header Cache-Control \"public, must-revalidate, proxy-revalidate\";\n";
				} else {
					$common_rules .= "    add_header Cache-Control \"max-age=" . $lifetime . ", public, must-revalidate, proxy-revalidate\";\n";
				}
				break;

			case 'no_cache':
				$common_rules .= "    add_header Pragma \"no-cache\";\n";
				$common_rules .= "    add_header Cache-Control \"max-age=0, private, no-store, no-cache, must-revalidate\";\n";
				break;
			}
		}

		$rules = '';
		$rules .= W3TC_MARKER_BEGIN_PGCACHE_CACHE . "\n";

		if ( !empty( $common_rules ) ) {
			$rules .= "location ~ " . $cache_dir . ".*html$ {\n";
			$rules .= $common_rules;
			$rules .= "}\n";
		}

		if ( $brotli ) {
			$maybe_xml = '';
			if ($config->get_boolean('pgcache.cache.nginx_handle_xml')) {
				$maybe_xml = "\n" .
					"        text/xml xml_br;\n" .
					"    ";
			}

			$rules .= "location ~ " . $cache_dir . ".*br$ {\n";
			$rules .= "    brotli off;\n";
			$rules .= "    types {" . $maybe_xml . "}\n";
			$rules .= "    default_type text/html;\n";
			$rules .= $common_rules;
			$rules .= "    add_header Content-Encoding br;\n";
			$rules .= "}\n";
		}

		if ( $compression ) {
			$maybe_xml = '';
			if ($config->get_boolean('pgcache.cache.nginx_handle_xml')) {
				$maybe_xml = "\n" .
					"        text/xml xml_gzip;\n" .
					"    ";
			}

			$rules .= "location ~ " . $cache_dir . ".*gzip$ {\n";
			$rules .= "    gzip off;\n";
			$rules .= "    types {" . $maybe_xml . "}\n";
			$rules .= "    default_type text/html;\n";
			$rules .= $common_rules;
			$rules .= "    add_header Content-Encoding gzip;\n";
			$rules .= "}\n";
		}

		$rules .= W3TC_MARKER_END_PGCACHE_CACHE . "\n";

		return $rules;
	}
}
