<?php
if ( ! defined( 'ABSPATH' ) ) {
    exit;
}

class FFASCACHEMANAGER_Cache_Tools {

    const OPTION_NAME = 'ffascachemanager_cache_settings';
    const LOG_OPTION = 'ffascachemanager_cache_prewarm_log';
    const PENDING_OPTION = 'ffascachemanager_cache_prewarm_pending';
    const GC_HOOK = 'ffascachemanager_cache_gc';
    const CACHE_MARKER = 'FFAS CACHE MANAGER PAGE CACHE';
    const BROWSER_CACHE_MARKER = 'FFAS CACHE MANAGER STATIC ASSET CACHE';
    const PREWARM_QUEUE_OPTION = 'ffascachemanager_cache_prewarm_queue';
    const PREWARM_BATCH = 20;

    public static function register_settings() {
        register_setting(
            'ffascachemanager_cache',
            self::OPTION_NAME,
            array( 'sanitize_callback' => array( __CLASS__, 'sanitize_settings' ) )
        );
        add_action( 'update_option_' . self::OPTION_NAME, array( __CLASS__, 'handle_settings_update' ), 10, 2 );
    }

    public static function sanitize_settings( $input ) {
        $clean = is_array( $input ) ? $input : array();
        $existing = get_option( self::OPTION_NAME, array() );

        if ( array_key_exists( 'enabled', $clean ) ) {
            $clean['enabled'] = ! empty( $clean['enabled'] ) ? 1 : 0;
        } else {
            $clean['enabled'] = ! empty( $existing['enabled'] ) ? 1 : 0;
        }

        $clean['clear_on_save'] = ! empty( $clean['clear_on_save'] ) ? 1 : 0;
        $clean['skip_woocommerce'] = ! empty( $clean['skip_woocommerce'] ) ? 1 : 0;
        $clean['exclude_urls'] = isset( $clean['exclude_urls'] ) ? sanitize_textarea_field( $clean['exclude_urls'] ) : '';
        $clean['prewarm_auto'] = ! empty( $clean['prewarm_auto'] ) ? 1 : 0;
        $clean['prewarm_limit'] = isset( $clean['prewarm_limit'] ) ? max( 1, intval( $clean['prewarm_limit'] ) ) : 200;
        $clean['prewarm_delay'] = isset( $clean['prewarm_delay'] ) ? max( 0, intval( $clean['prewarm_delay'] ) ) : 200;
        $clean['mobile_cache'] = ! empty( $clean['mobile_cache'] ) ? 1 : 0;
        $clean['cache_ttl'] = isset( $clean['cache_ttl'] ) ? max( 60, intval( $clean['cache_ttl'] ) ) : 3600;
        $clean['browser_cache'] = ! empty( $clean['browser_cache'] ) ? 1 : 0;
        $server = isset( $clean['server_type'] ) ? sanitize_key( $clean['server_type'] ) : '';
        $clean['server_type'] = $server !== '' ? $server : ( isset( $existing['server_type'] ) ? $existing['server_type'] : '' );

        return $clean;
    }

    public static function render_page() {
        if ( ! current_user_can( 'manage_options' ) ) {
            return;
        }

        $settings = get_option( self::OPTION_NAME, array() );
        $enabled = ! empty( $settings['enabled'] );
        $clear_on_save = ! empty( $settings['clear_on_save'] );
        $skip_woocommerce = ! empty( $settings['skip_woocommerce'] );
        $exclude_urls = isset( $settings['exclude_urls'] ) ? $settings['exclude_urls'] : '';
        $prewarm_auto = ! empty( $settings['prewarm_auto'] );
        $prewarm_limit = isset( $settings['prewarm_limit'] ) ? (int) $settings['prewarm_limit'] : 200;
        $prewarm_delay = isset( $settings['prewarm_delay'] ) ? (int) $settings['prewarm_delay'] : 200;
        $mobile_cache = ! empty( $settings['mobile_cache'] );
        $cache_ttl = isset( $settings['cache_ttl'] ) ? (int) $settings['cache_ttl'] : 3600;
        $browser_cache = ! array_key_exists( 'browser_cache', $settings ) || ! empty( $settings['browser_cache'] );
        $server_type = isset( $settings['server_type'] ) ? $settings['server_type'] : '';
        $detected = self::detect_server_type();
        $server_type = $server_type !== '' ? $server_type : $detected;
        $log = get_option( self::LOG_OPTION, array() );
        // phpcs:ignore WordPress.Security.NonceVerification.Recommended - read-only param, sanitized inline.
        $status = isset( $_GET['ffascachemanager_cache_status'] ) ? sanitize_text_field( wp_unslash( $_GET['ffascachemanager_cache_status'] ) ) : '';
        // phpcs:ignore WordPress.Security.NonceVerification.Recommended - read-only param, sanitized inline.
        $prewarm_status = isset( $_GET['ffascachemanager_prewarm_status'] ) ? sanitize_text_field( wp_unslash( $_GET['ffascachemanager_prewarm_status'] ) ) : '';
        // phpcs:ignore WordPress.Security.NonceVerification.Recommended - read-only param, sanitized inline.
        $htaccess_status = isset( $_GET['ffascachemanager_cache_rules'] ) ? sanitize_text_field( wp_unslash( $_GET['ffascachemanager_cache_rules'] ) ) : '';
        ?>
        <div class="wrap ffascachemanager-wrap">
            <h1><?php esc_html_e( 'Cache Tool', 'ffas-cache-manager' ); ?></h1>
            <p><?php esc_html_e( 'Configure basic page caching rules and when the cache should be cleared.', 'ffas-cache-manager' ); ?></p>

            <div class="ffascachemanager-card">
                <p><strong><?php esc_html_e( 'Cache status:', 'ffas-cache-manager' ); ?></strong> <?php echo $enabled ? esc_html__( 'Enabled', 'ffas-cache-manager' ) : esc_html__( 'Disabled', 'ffas-cache-manager' ); ?></p>
            </div>

            <?php if ( $status === 'cleared' ) : ?>
                <div class="notice notice-success is-dismissible">
                    <p><?php esc_html_e( 'Cache cleared successfully.', 'ffas-cache-manager' ); ?></p>
                </div>
            <?php elseif ( $status === 'enabled' ) : ?>
                <div class="notice notice-success is-dismissible">
                    <p><?php esc_html_e( 'Cache enabled.', 'ffas-cache-manager' ); ?></p>
                </div>
            <?php elseif ( $status === 'disabled' ) : ?>
                <div class="notice notice-warning is-dismissible">
                    <p><?php esc_html_e( 'Cache disabled. No new cache files will be created.', 'ffas-cache-manager' ); ?></p>
                </div>
            <?php endif; ?>
            <?php if ( $prewarm_status === 'done' ) : ?>
                <div class="notice notice-success is-dismissible">
                    <p><?php esc_html_e( 'Cache pre-warm finished. Check the status card for details.', 'ffas-cache-manager' ); ?></p>
                </div>
            <?php elseif ( $prewarm_status === 'queued' ) : ?>
                <div class="notice notice-info is-dismissible">
                    <p><?php esc_html_e( 'Cache pre-warm has been queued and will run shortly in the background.', 'ffas-cache-manager' ); ?></p>
                </div>
            <?php endif; ?>
            <?php if ( $htaccess_status === 'updated' ) : ?>
                <div class="notice notice-success is-dismissible">
                    <p><?php esc_html_e( 'Cache rewrite rules updated.', 'ffas-cache-manager' ); ?></p>
                </div>
            <?php elseif ( $htaccess_status === 'failed' ) : ?>
                <div class="notice notice-error is-dismissible">
                    <p><?php esc_html_e( 'Could not update .htaccess. Please add the rules manually.', 'ffas-cache-manager' ); ?></p>
                </div>
            <?php endif; ?>

            <form method="post" action="<?php echo esc_url( admin_url( 'admin-post.php' ) ); ?>" class="ffascachemanager-card ffascachemanager-form-card">
                <?php wp_nonce_field( 'ffascachemanager_toggle_cache' ); ?>
                <input type="hidden" name="action" value="ffascachemanager_toggle_cache" />
                <input type="hidden" name="cache_enabled" value="<?php echo $enabled ? '0' : '1'; ?>" />
                <?php submit_button( $enabled ? __( 'Disable cache', 'ffas-cache-manager' ) : __( 'Enable cache', 'ffas-cache-manager' ), 'primary', 'submit', false ); ?>
            </form>

            <form method="post" action="options.php" class="ffascachemanager-card ffascachemanager-form-card">
                <?php settings_fields( 'ffascachemanager_cache' ); ?>
                <p>
                    <label for="ffascachemanager-cache-server"><?php esc_html_e( 'Server type', 'ffas-cache-manager' ); ?></label>
                    <select id="ffascachemanager-cache-server" name="<?php echo esc_attr( self::OPTION_NAME ); ?>[server_type]">
                        <option value=""><?php esc_html_e( 'Auto-detect', 'ffas-cache-manager' ); ?></option>
                        <option value="apache" <?php selected( $server_type, 'apache' ); ?>><?php esc_html_e( 'Apache/LiteSpeed', 'ffas-cache-manager' ); ?></option>
                        <option value="nginx" <?php selected( $server_type, 'nginx' ); ?>><?php esc_html_e( 'Nginx', 'ffas-cache-manager' ); ?></option>
                        <option value="unknown" <?php selected( $server_type, 'unknown' ); ?>><?php esc_html_e( 'Other / Unknown', 'ffas-cache-manager' ); ?></option>
                    </select>
                    <span class="description"><?php esc_html_e( 'Auto-detected server:', 'ffas-cache-manager' ); ?> <?php echo esc_html( $detected ? $detected : __( 'unknown', 'ffas-cache-manager' ) ); ?></span>
                </p>
                <p>
                    <label>
                        <input type="checkbox" name="<?php echo esc_attr( self::OPTION_NAME ); ?>[clear_on_save]" value="1" <?php checked( $clear_on_save ); ?> />
                        <?php esc_html_e( 'Clean the cache when a page is created or modified', 'ffas-cache-manager' ); ?>
                    </label>
                </p>
                <p>
                    <label>
                        <input type="checkbox" name="<?php echo esc_attr( self::OPTION_NAME ); ?>[skip_woocommerce]" value="1" <?php checked( $skip_woocommerce ); ?> />
                        <?php esc_html_e( 'Do not cache WooCommerce checkout and basket pages', 'ffas-cache-manager' ); ?>
                    </label>
                </p>
                <p class="description"><?php esc_html_e( 'Pages containing forms are excluded to prevent stale nonces and visitor-specific form state from being cached.', 'ffas-cache-manager' ); ?></p>
                <p>
                    <label>
                        <input type="checkbox" name="<?php echo esc_attr( self::OPTION_NAME ); ?>[mobile_cache]" value="1" <?php checked( $mobile_cache ); ?> />
                        <?php esc_html_e( 'Create separate cache for mobile devices', 'ffas-cache-manager' ); ?>
                    </label>
                </p>
                <p>
                    <label for="ffascachemanager-cache-exclude"><?php esc_html_e( 'Exclude URLs from caching (one per line)', 'ffas-cache-manager' ); ?></label>
                    <textarea id="ffascachemanager-cache-exclude" class="large-text code" name="<?php echo esc_attr( self::OPTION_NAME ); ?>[exclude_urls]" rows="4" placeholder="/account\n/contact"><?php echo esc_textarea( $exclude_urls ); ?></textarea>
                    <span class="description"><?php esc_html_e( 'You can use full URLs or paths. Add * at the end to match prefixes.', 'ffas-cache-manager' ); ?></span>
                </p>
                <p>
                    <label for="ffascachemanager-cache-ttl"><?php esc_html_e( 'Cache lifetime (seconds)', 'ffas-cache-manager' ); ?></label>
                    <input id="ffascachemanager-cache-ttl" type="number" min="60" max="86400" class="small-text" name="<?php echo esc_attr( self::OPTION_NAME ); ?>[cache_ttl]" value="<?php echo esc_attr( max( 60, $cache_ttl ) ); ?>" />
                    <span class="description"><?php esc_html_e( 'Cached HTML is never served after this lifetime; garbage collection removes expired files.', 'ffas-cache-manager' ); ?></span>
                </p>
                <p>
                    <label>
                        <input type="hidden" name="<?php echo esc_attr( self::OPTION_NAME ); ?>[browser_cache]" value="0" />
                        <input type="checkbox" name="<?php echo esc_attr( self::OPTION_NAME ); ?>[browser_cache]" value="1" <?php checked( $browser_cache ); ?> />
                        <?php esc_html_e( 'Add long-lived browser cache headers for versioned images, fonts, CSS, JavaScript, audio, and video', 'ffas-cache-manager' ); ?>
                    </label>
                </p>
                <p>
                    <label>
                        <input type="checkbox" name="<?php echo esc_attr( self::OPTION_NAME ); ?>[prewarm_auto]" value="1" <?php checked( $prewarm_auto ); ?> />
                        <?php esc_html_e( 'Auto pre-warm cache when enabled or after content updates', 'ffas-cache-manager' ); ?>
                    </label>
                </p>
                <p>
                    <label for="ffascachemanager-cache-prewarm-limit"><?php esc_html_e( 'Pre-warm URL limit (max 200)', 'ffas-cache-manager' ); ?></label>
                    <input id="ffascachemanager-cache-prewarm-limit" type="number" min="1" max="200" class="small-text" name="<?php echo esc_attr( self::OPTION_NAME ); ?>[prewarm_limit]" value="<?php echo esc_attr( min( 200, max( 1, $prewarm_limit ) ) ); ?>" />
                </p>
                <p>
                    <label for="ffascachemanager-cache-prewarm-delay"><?php esc_html_e( 'Crawl delay (milliseconds)', 'ffas-cache-manager' ); ?></label>
                    <input id="ffascachemanager-cache-prewarm-delay" type="number" min="0" max="5000" class="small-text" name="<?php echo esc_attr( self::OPTION_NAME ); ?>[prewarm_delay]" value="<?php echo esc_attr( max( 0, $prewarm_delay ) ); ?>" />
                    <span class="description"><?php esc_html_e( 'Recommended 200-500ms to avoid server spikes.', 'ffas-cache-manager' ); ?></span>
                </p>
                <?php submit_button( __( 'Save cache settings', 'ffas-cache-manager' ), 'secondary', 'submit', false ); ?>
            </form>

            <?php if ( $server_type === 'nginx' || $server_type === 'unknown' ) : ?>
                <div class="ffascachemanager-card">
                    <h3><?php esc_html_e( 'Nginx cache rules (manual)', 'ffas-cache-manager' ); ?></h3>
                    <p><?php esc_html_e( 'Add the following static-asset expiry rules to your Nginx server block. HTML page-cache files continue through WordPress so request safety and TTL checks are applied.', 'ffas-cache-manager' ); ?></p>
                    <textarea class="large-text code" rows="8" readonly><?php echo esc_textarea( self::nginx_rules_snippet() ); ?></textarea>
                </div>
            <?php else : ?>
                <div class="ffascachemanager-card">
                    <h3><?php esc_html_e( 'Apache/LiteSpeed cache rules', 'ffas-cache-manager' ); ?></h3>
                    <p><?php esc_html_e( 'Static-asset expiry rules are managed automatically in .htaccess. HTML page-cache files continue through WordPress so request safety and TTL checks are applied.', 'ffas-cache-manager' ); ?></p>
                    <textarea class="large-text code" rows="8" readonly><?php echo esc_textarea( self::apache_rules_snippet() ); ?></textarea>
                </div>
            <?php endif; ?>

            <div class="ffascachemanager-card">
                <h3><?php esc_html_e( 'Expiry-header reference file', 'ffas-cache-manager' ); ?></h3>
                <p><?php esc_html_e( 'A complete Apache reference covering common images, scripts, styles, fonts, documents, audio, and video is included with the plugin.', 'ffas-cache-manager' ); ?></p>
                <p><a href="<?php echo esc_url( FFASCACHEMANAGER_PLUGIN_URL . 'expires-headers.txt' ); ?>" target="_blank" rel="noopener noreferrer"><?php esc_html_e( 'Open expires-headers.txt', 'ffas-cache-manager' ); ?></a></p>
            </div>

            <form method="post" action="<?php echo esc_url( admin_url( 'admin-post.php' ) ); ?>" class="ffascachemanager-card ffascachemanager-form-card ffascachemanager-long-task">
                <?php wp_nonce_field( 'ffascachemanager_prewarm_cache' ); ?>
                <input type="hidden" name="action" value="ffascachemanager_prewarm_cache" />
                <?php submit_button( __( 'Pre-warm cache now', 'ffas-cache-manager' ), 'secondary', 'submit', false ); ?>
                <p class="description"><?php esc_html_e( 'Crawl sitemap, pages, and posts to generate cache files.', 'ffas-cache-manager' ); ?></p>
            </form>

            <form method="post" action="<?php echo esc_url( admin_url( 'admin-post.php' ) ); ?>" class="ffascachemanager-card ffascachemanager-form-card">
                <?php wp_nonce_field( 'ffascachemanager_clear_cache' ); ?>
                <input type="hidden" name="action" value="ffascachemanager_clear_cache" />
                <?php submit_button( __( 'Clean Cache', 'ffas-cache-manager' ), 'secondary', 'submit', false ); ?>
            </form>

            <div class="ffascachemanager-card">
                <h3><?php esc_html_e( 'Pre-warm status', 'ffas-cache-manager' ); ?></h3>
                <?php if ( empty( $log ) ) : ?>
                    <p><?php esc_html_e( 'No pre-warm has been run yet.', 'ffas-cache-manager' ); ?></p>
                <?php else : ?>
                    <p><strong><?php esc_html_e( 'Last run:', 'ffas-cache-manager' ); ?></strong>
                        <?php echo esc_html( isset( $log['time'] ) ? date_i18n( get_option( 'date_format' ) . ' ' . get_option( 'time_format' ), intval( $log['time'] ) ) : __( 'Unknown', 'ffas-cache-manager' ) ); ?>
                    </p>
                    <p><strong><?php esc_html_e( 'Source:', 'ffas-cache-manager' ); ?></strong> <?php echo esc_html( isset( $log['source'] ) ? $log['source'] : '-' ); ?></p>
                    <p><strong><?php esc_html_e( 'Attempted:', 'ffas-cache-manager' ); ?></strong> <?php echo esc_html( isset( $log['attempted'] ) ? intval( $log['attempted'] ) : 0 ); ?>
                        | <strong><?php esc_html_e( 'Succeeded:', 'ffas-cache-manager' ); ?></strong> <?php echo esc_html( isset( $log['succeeded'] ) ? intval( $log['succeeded'] ) : 0 ); ?>
                    </p>
                    <?php if ( ! empty( $log['errors'] ) && is_array( $log['errors'] ) ) : ?>
                        <p><strong><?php esc_html_e( 'Errors:', 'ffas-cache-manager' ); ?></strong></p>
                        <ul>
                            <?php foreach ( array_slice( $log['errors'], 0, 5 ) as $error ) : ?>
                                <li><?php echo esc_html( $error ); ?></li>
                            <?php endforeach; ?>
                        </ul>
                    <?php endif; ?>
                <?php endif; ?>
            </div>
        </div>
        <?php
    }

    public static function handle_toggle_cache() {
        if ( ! current_user_can( 'manage_options' ) ) {
            wp_die( esc_html__( 'You do not have permission to update the cache.', 'ffas-cache-manager' ) );
        }

        check_admin_referer( 'ffascachemanager_toggle_cache' );

        $settings = get_option( self::OPTION_NAME, array() );
        if ( ! is_array( $settings ) ) {
            $settings = array();
        }

        $enabled = isset( $_POST['cache_enabled'] ) ? intval( $_POST['cache_enabled'] ) : 0;
        $settings['enabled'] = $enabled ? 1 : 0;
        update_option( self::OPTION_NAME, $settings );

        $rules_status = 'updated';
        if ( ! $settings['enabled'] ) {
            self::clear_cache();
        } else {
            self::schedule_gc();
        }
        $rules_status = self::maybe_write_apache_rules() ? 'updated' : 'failed';
        if ( $settings['enabled'] && ! empty( $settings['prewarm_auto'] ) ) {
            self::schedule_prewarm( 'enabled' );
        }

        $status = $settings['enabled'] ? 'enabled' : 'disabled';
        wp_safe_redirect( admin_url( 'admin.php?page=ffascachemanager-cache-tools&ffascachemanager_cache_status=' . $status . '&ffascachemanager_cache_rules=' . $rules_status ) );
        exit;
    }

    public static function handle_clear_cache() {
        if ( ! current_user_can( 'manage_options' ) ) {
            wp_die( esc_html__( 'You do not have permission to clear the cache.', 'ffas-cache-manager' ) );
        }

        check_admin_referer( 'ffascachemanager_clear_cache' );

        self::clear_cache();

        wp_safe_redirect( admin_url( 'admin.php?page=ffascachemanager-cache-tools&ffascachemanager_cache_status=cleared' ) );
        exit;
    }

    public static function handle_settings_update( $old_value, $value ) {
        $enabled = ! empty( $value['enabled'] );
        $server = isset( $value['server_type'] ) ? $value['server_type'] : '';
        if ( $server === '' ) {
            $server = self::detect_server_type();
        }

        if ( $enabled ) {
            self::schedule_gc();
        }
        if ( $server === 'apache' ) {
            self::maybe_write_apache_rules();
        } else {
            self::remove_apache_rules( true );
        }
    }

    public static function maybe_clear_on_save( $post_id, $post ) {
        if ( wp_is_post_autosave( $post_id ) || wp_is_post_revision( $post_id ) ) {
            return;
        }
        $settings = get_option( self::OPTION_NAME, array() );
        if ( empty( $settings['enabled'] ) || empty( $settings['clear_on_save'] ) ) {
            return;
        }
        // Content can affect archives, menus, related-post blocks, sitemaps, and
        // shared fragments, so a complete purge is safer than a partial one.
        self::clear_cache();
        if ( ! empty( $settings['prewarm_auto'] ) ) {
            self::schedule_prewarm( 'content_update' );
        }
    }

    public static function handle_prewarm_cache() {
        if ( ! current_user_can( 'manage_options' ) ) {
            wp_die( esc_html__( 'You do not have permission to pre-warm the cache.', 'ffas-cache-manager' ) );
        }

        check_admin_referer( 'ffascachemanager_prewarm_cache' );

        self::schedule_prewarm( 'manual' );

        wp_safe_redirect( admin_url( 'admin.php?page=ffascachemanager-cache-tools&ffascachemanager_prewarm_status=queued' ) );
        exit;
    }

    public static function handle_scheduled_prewarm() {
        $pending = get_option( self::PENDING_OPTION, array() );
        $source = isset( $pending['source'] ) ? $pending['source'] : 'auto';
        delete_option( self::PENDING_OPTION );
        self::run_prewarm( $source );
    }

    public static function maybe_serve_cache() {
        if ( ! self::is_cacheable_request() ) {
            return;
        }

        $file = self::cache_file_path();
        if ( ! $file || ! file_exists( $file ) ) {
            return;
        }

        $settings = get_option( self::OPTION_NAME, array() );
        $ttl = isset( $settings['cache_ttl'] ) ? max( 60, intval( $settings['cache_ttl'] ) ) : 3600;
        $mtime = @filemtime( $file );
        if ( ! $mtime || ( time() - $mtime ) > $ttl ) {
            wp_delete_file( $file );
            return;
        }

        $contents = @file_get_contents( $file );
        if ( $contents === false ) {
            return;
        }

        if ( ! headers_sent() ) {
            header( 'X-FFAS-Cache-Manager: HIT' );
            header( 'Cache-Control: no-cache, must-revalidate' );
            header( 'Vary: Accept-Encoding', false );
        }
        // phpcs:ignore
        echo $contents;
        exit;
    }

    public static function start_cache_buffer() {
        if ( ! self::is_cacheable_request() ) {
            return;
        }

        ob_start( array( __CLASS__, 'cache_output' ) );
    }

    public static function cache_output( $buffer ) {
        if ( stripos( $buffer, '<html' ) === false || self::response_must_not_be_cached() ) {
            return $buffer;
        }

        $settings = get_option( self::OPTION_NAME, array() );
        if ( empty( $settings['enabled'] ) ) {
            return $buffer;
        }

        $file = self::cache_file_path();
        if ( ! $file ) {
            return $buffer;
        }

        if ( self::contains_form( $buffer ) ) {
            return $buffer;
        }

        $dir = dirname( $file );
        if ( ! wp_mkdir_p( $dir ) ) {
            return $buffer;
        }

        $temporary = $file . '.tmp-' . wp_generate_password( 8, false, false );
        $written = @file_put_contents( $temporary, $buffer, LOCK_EX );
        // phpcs:ignore
        if ( false === $written || ! @rename( $temporary, $file ) ) {
            if ( file_exists( $temporary ) ) {
                wp_delete_file( $temporary );
            }
            return $buffer;
        }
        if ( ! headers_sent() ) {
            header( 'X-FFAS-Cache-Manager: MISS' );
            header( 'Cache-Control: no-cache, must-revalidate' );
            header( 'Vary: Accept-Encoding', false );
        }
        return $buffer;
    }

    private static function is_cacheable_request() {
        if ( is_admin() || wp_doing_ajax() || ( defined( 'REST_REQUEST' ) && REST_REQUEST ) ) {
            return false;
        }

        if ( is_feed() || is_preview() || is_search() || is_404() || is_trackback() || is_embed() || ( function_exists( 'is_customize_preview' ) && is_customize_preview() ) ) {
            return false;
        }

        if ( is_user_logged_in() ) {
            return false;
        }

        if ( ! isset( $_SERVER['REQUEST_METHOD'] ) || strtoupper( $_SERVER['REQUEST_METHOD'] ) !== 'GET' ) {
            return false;
        }

        if ( defined( 'DONOTCACHEPAGE' ) && DONOTCACHEPAGE ) {
            return false;
        }

        if ( self::has_private_request_cookie() ) {
            return false;
        }

        $settings = get_option( self::OPTION_NAME, array() );
        if ( empty( $settings['enabled'] ) ) {
            return false;
        }

        if ( ! empty( $settings['skip_woocommerce'] ) ) {
            if ( function_exists( 'is_checkout' ) && is_checkout() ) {
                return false;
            }
            if ( function_exists( 'is_cart' ) && is_cart() ) {
                return false;
            }
            $request_uri = isset( $_SERVER['REQUEST_URI'] ) ? $_SERVER['REQUEST_URI'] : '';
            if ( stripos( $request_uri, 'checkout' ) !== false || stripos( $request_uri, 'cart' ) !== false ) {
                return false;
            }
        }

        $request_uri = isset( $_SERVER['REQUEST_URI'] ) ? wp_unslash( $_SERVER['REQUEST_URI'] ) : '';
        if ( self::has_non_tracking_query( $request_uri ) ) {
            return false;
        }
        if ( self::is_excluded_url( $request_uri ) ) {
            return false;
        }

        return true;
    }

    public static function maybe_clear_all() {
        $settings = get_option( self::OPTION_NAME, array() );
        if ( ! empty( $settings['enabled'] ) ) {
            self::clear_cache();
        }
    }

    public static function refresh_server_rules() {
        return self::maybe_write_apache_rules();
    }

    private static function has_private_request_cookie() {
        if ( empty( $_COOKIE ) || ! is_array( $_COOKIE ) ) {
            return false;
        }
        $private_prefixes = array(
            'wordpress_logged_in_',
            'wordpress_sec_',
            'wp-postpass_',
            'comment_author_',
            'woocommerce_items_in_cart',
            'woocommerce_cart_hash',
            'wp_woocommerce_session_',
            'PHPSESSID',
        );
        foreach ( array_keys( $_COOKIE ) as $cookie_name ) {
            foreach ( $private_prefixes as $prefix ) {
                if ( 0 === strpos( (string) $cookie_name, $prefix ) ) {
                    return true;
                }
            }
        }
        return false;
    }

    private static function has_non_tracking_query( $uri ) {
        $query = wp_parse_url( $uri, PHP_URL_QUERY );
        if ( ! is_string( $query ) || '' === $query ) {
            return false;
        }
        parse_str( $query, $params );
        $tracking = array( 'utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content', 'gclid', 'fbclid' );
        foreach ( $tracking as $key ) {
            unset( $params[ $key ] );
        }
        return ! empty( $params );
    }

    private static function response_must_not_be_cached() {
        $status = http_response_code();
        if ( $status && 200 !== intval( $status ) ) {
            return true;
        }
        foreach ( headers_list() as $header ) {
            $lower = strtolower( $header );
            if ( 0 === strpos( $lower, 'set-cookie:' ) ||
                ( 0 === strpos( $lower, 'cache-control:' ) && preg_match( '/\b(?:no-cache|no-store|private)\b/', $lower ) ) ) {
                return true;
            }
        }
        return false;
    }

    private static function cache_file_path() {
        if ( ! isset( $_SERVER['REQUEST_URI'] ) ) {
            return '';
        }
        return self::cache_file_path_for_uri( wp_unslash( $_SERVER['REQUEST_URI'] ) );
    }

    public static function clear_cache() {
        $dir = self::cache_base_dir();
        if ( ! is_dir( $dir ) ) {
            return true;
        }

        $iterator = new RecursiveIteratorIterator(
            new RecursiveDirectoryIterator( $dir, RecursiveDirectoryIterator::SKIP_DOTS ),
            RecursiveIteratorIterator::CHILD_FIRST
        );

        foreach ( $iterator as $item ) {
            if ( $item->isDir() ) {
                // phpcs:ignore
                @rmdir( $item->getPathname() );
            } else {
                wp_delete_file( $item->getPathname() );
            }
        }

        // phpcs:ignore
        @rmdir( $dir );
        return ! is_dir( $dir );
    }

    private static function clear_cache_for_post( $post_id, $post ) {
        $urls = array();
        $permalink = get_permalink( $post_id );
        if ( $permalink ) {
            $urls[] = $permalink;
        }

        if ( $post instanceof WP_Post ) {
            if ( $post->post_type === 'post' ) {
                $urls[] = home_url( '/' );
                $posts_page = intval( get_option( 'page_for_posts' ) );
                if ( $posts_page ) {
                    $posts_url = get_permalink( $posts_page );
                    if ( $posts_url ) {
                        $urls[] = $posts_url;
                    }
                }
            } elseif ( $post->post_type === 'page' ) {
                $front_id = intval( get_option( 'page_on_front' ) );
                $posts_page = intval( get_option( 'page_for_posts' ) );
                if ( $front_id && $front_id === $post_id ) {
                    $urls[] = home_url( '/' );
                }
                if ( $posts_page && $posts_page === $post_id ) {
                    $posts_url = get_permalink( $posts_page );
                    if ( $posts_url ) {
                        $urls[] = $posts_url;
                    }
                }
            } elseif ( $post->post_type === 'product' ) {
                $shop_id = function_exists( 'wc_get_page_id' ) ? wc_get_page_id( 'shop' ) : 0;
                if ( $shop_id && $shop_id !== $post_id ) {
                    $shop_url = get_permalink( $shop_id );
                    if ( $shop_url ) {
                        $urls[] = $shop_url;
                    }
                }
            }
        }

        $urls = array_values( array_unique( array_filter( $urls ) ) );
        foreach ( $urls as $url ) {
            self::clear_cache_for_url( $url );
        }
    }

    private static function clear_cache_for_url( $url ) {
        $path = wp_parse_url( $url, PHP_URL_PATH );
        if ( $path === null ) {
            return;
        }

        $variants = array();
        $path = $path === '' ? '/' : $path;
        $variants[] = $path;
        if ( $path !== '/' && substr( $path, -1 ) === '/' ) {
            $variants[] = rtrim( $path, '/' );
        } elseif ( $path !== '/' ) {
            $variants[] = $path . '/';
        }

        foreach ( $variants as $variant ) {
            $desktop = self::cache_file_path_for_uri( $variant, false );
            if ( $desktop && file_exists( $desktop ) ) {
                wp_delete_file( $desktop );
            }
            $mobile = self::cache_file_path_for_uri( $variant, true );
            if ( $mobile && file_exists( $mobile ) ) {
                wp_delete_file( $mobile );
            }
        }
    }

    private static function cache_file_path_for_uri( $uri, $force_mobile = null ) {
        $host = wp_parse_url( home_url(), PHP_URL_HOST );
        if ( empty( $host ) ) {
            return '';
        }

        $request_key = self::normalize_request_uri( $uri );
        if ( '' === $request_key || false !== strpos( rawurldecode( $request_key ), "\0" ) ) {
            return '';
        }
        $settings = get_option( self::OPTION_NAME, array() );
        $is_mobile = $force_mobile;
        if ( $is_mobile === null ) {
            $is_mobile = ! empty( $settings['mobile_cache'] ) && function_exists( 'wp_is_mobile' ) && wp_is_mobile();
        }
        $base = trailingslashit( self::cache_base_dir() ) . sanitize_file_name( $host ) . '/';
        if ( $is_mobile ) {
            $base .= 'mobile/';
        }
        return $base . hash( 'sha256', $request_key ) . '.html';
    }

    private static function normalize_request_uri( $uri ) {
        $parts = wp_parse_url( $uri );
        if ( empty( $parts ) ) {
            return $uri;
        }

        $path = isset( $parts['path'] ) ? $parts['path'] : '/';
        $query = isset( $parts['query'] ) ? $parts['query'] : '';
        if ( $query === '' ) {
            return $path;
        }

        parse_str( $query, $params );
        $drop = array( 'utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content', 'gclid', 'fbclid' );
        foreach ( $drop as $key ) {
            if ( isset( $params[ $key ] ) ) {
                unset( $params[ $key ] );
            }
        }

        if ( empty( $params ) ) {
            return $path;
        }

        return $path . '?' . http_build_query( $params );
    }

    private static function parse_exclude_urls() {
        $settings = get_option( self::OPTION_NAME, array() );
        $raw = isset( $settings['exclude_urls'] ) ? $settings['exclude_urls'] : '';
        $lines = preg_split( '/\r\n|\r|\n/', (string) $raw );
        $urls = array();
        foreach ( $lines as $line ) {
            $line = trim( $line );
            if ( $line === '' ) {
                continue;
            }
            $urls[] = $line;
        }
        return $urls;
    }

    private static function is_excluded_url( $request_uri ) {
        $excludes = self::parse_exclude_urls();
        if ( empty( $excludes ) ) {
            return false;
        }

        $normalized = self::normalize_request_uri( $request_uri );
        foreach ( $excludes as $line ) {
            $is_prefix = false;
            if ( substr( $line, -1 ) === '*' ) {
                $is_prefix = true;
                $line = rtrim( $line, '*' );
            }

            $compare = '';
            if ( preg_match( '#^https?://#i', $line ) ) {
                $compare = self::normalize_request_uri( wp_parse_url( $line, PHP_URL_PATH ) ?: '/' );
            } else {
                $compare = self::normalize_request_uri( $line );
            }

            if ( $compare === '' ) {
                continue;
            }

            if ( $is_prefix ) {
                if ( strpos( $normalized, $compare ) === 0 ) {
                    return true;
                }
            } elseif ( $normalized === $compare ) {
                return true;
            }
        }

        return false;
    }

    private static function minify_html_safe( $content ) {
        $placeholders = array();
        $index = 0;
        $content = preg_replace_callback( '/<(script|style)\b[^>]*>.*?<\/\1>/is', function ( $matches ) use ( &$placeholders, &$index ) {
            $token = '__FFASCACHEMANAGER_CACHE_BLOCK_' . $index . '__';
            $placeholders[ $token ] = $matches[0];
            $index++;
            return $token;
        }, $content );

        $content = preg_replace( '/<!--(?!\\s*\\[if).*?-->/', '', $content );
        $content = preg_replace( '/\s+/', ' ', $content );
        $content = preg_replace( '/>\s+</', '><', $content );

        if ( ! empty( $placeholders ) ) {
            $content = str_replace( array_keys( $placeholders ), array_values( $placeholders ), $content );
        }

        return trim( $content );
    }

    private static function contains_form( $html ) {
        return (bool) preg_match( '/<form\b[^>]*>/i', $html );
    }

    private static function schedule_prewarm( $source ) {
        if ( wp_next_scheduled( 'ffascachemanager_cache_prewarm' ) ) {
            return;
        }

        update_option( self::PENDING_OPTION, array(
            'source' => $source,
            'time'   => time(),
        ), false );

        wp_schedule_single_event( time() + 30, 'ffascachemanager_cache_prewarm' );
    }

    private static function run_prewarm( $source ) {
        $settings = get_option( self::OPTION_NAME, array() );
        if ( empty( $settings['enabled'] ) ) {
            return;
        }

        if ( function_exists( 'set_time_limit' ) ) {
            @set_time_limit( 0 );
        }
        if ( function_exists( 'ini_set' ) ) {
            @ini_set( 'max_execution_time', '0' );
        }

        $limit = isset( $settings['prewarm_limit'] ) ? max( 1, intval( $settings['prewarm_limit'] ) ) : 200;
        $limit = min( 200, $limit );
        $delay = isset( $settings['prewarm_delay'] ) ? max( 0, intval( $settings['prewarm_delay'] ) ) : 200;
        $mobile_enabled = ! empty( $settings['mobile_cache'] );
        $mobile_headers = array(
            'user-agent' => 'Mozilla/5.0 (iPhone; CPU iPhone OS 13_6 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.1.2 Mobile/15E148 Safari/604.1',
        );

        $queue = get_option( self::PREWARM_QUEUE_OPTION, array() );
        if ( empty( $queue ) || ! is_array( $queue ) ) {
            $queue = self::collect_prewarm_urls( $limit );
            update_option( self::PREWARM_QUEUE_OPTION, $queue, false );
        }

        if ( empty( $queue ) ) {
            return;
        }

        $attempted = 0;
        $succeeded = 0;
        $errors = array();

        $batch = array_slice( $queue, 0, self::PREWARM_BATCH );
        $remaining = array_slice( $queue, self::PREWARM_BATCH );

        foreach ( $batch as $url ) {
            $path = wp_parse_url( $url, PHP_URL_PATH );
            $path = $path ? $path : '/';
            if ( self::is_excluded_url( $path ) ) {
                continue;
            }
            if ( ! empty( $settings['skip_woocommerce'] ) ) {
                if ( stripos( $path, 'checkout' ) !== false || stripos( $path, 'cart' ) !== false ) {
                    continue;
                }
            }

            $attempted++;
            $response = wp_remote_get( $url, array( 'timeout' => 5, 'redirection' => 2 ) );
            if ( is_wp_error( $response ) ) {
                /* translators: %s: text, %s: text. */
                $errors[] = sprintf( '%s: %s', $url, $response->get_error_message() );
            } else {
                $code = wp_remote_retrieve_response_code( $response );
                if ( $code >= 200 && $code < 400 ) {
                    $succeeded++;
                } else {
                    /* translators: %s: text, %d: number. */
                    $errors[] = sprintf( '%s: HTTP %d', $url, $code );
                }
            }

            if ( $mobile_enabled ) {
                $attempted++;
                $mobile_response = wp_remote_get( $url, array( 'timeout' => 5, 'redirection' => 2, 'headers' => $mobile_headers ) );
                if ( is_wp_error( $mobile_response ) ) {
                    /* translators: %s: text, %s: text. */
                    $errors[] = sprintf( '%s (mobile): %s', $url, $mobile_response->get_error_message() );
                } else {
                    $code = wp_remote_retrieve_response_code( $mobile_response );
                    if ( $code >= 200 && $code < 400 ) {
                        $succeeded++;
                    } else {
                        /* translators: %s: text, %d: number. */
                        $errors[] = sprintf( '%s (mobile): HTTP %d', $url, $code );
                    }
                }
            }

            if ( $delay > 0 ) {
                usleep( $delay * 1000 );
            }
        }

        update_option( self::LOG_OPTION, array(
            'time'      => time(),
            'source'    => $source,
            'attempted' => $attempted,
            'succeeded' => $succeeded,
            'errors'    => $errors,
            'limit'     => $limit,
            'delay'     => $delay,
        ), false );

        if ( ! empty( $remaining ) ) {
            update_option( self::PREWARM_QUEUE_OPTION, $remaining, false );
            wp_schedule_single_event( time() + 30, 'ffascachemanager_cache_prewarm' );
        } else {
            delete_option( self::PREWARM_QUEUE_OPTION );
        }
    }

    private static function collect_prewarm_urls( $limit ) {
        $urls = array( home_url( '/' ) );

        $sitemap_path = FFASCACHEMANAGER_Pro::get_root_file_path( 'sitemap.xml' );
        if ( file_exists( $sitemap_path ) ) {
            $xml = @file_get_contents( $sitemap_path );
            if ( $xml !== false ) {
                libxml_use_internal_errors( true );
                $doc = simplexml_load_string( $xml );
                if ( $doc !== false ) {
                    foreach ( $doc->url as $url_node ) {
                        if ( isset( $url_node->loc ) ) {
                            $loc = (string) $url_node->loc;
                            if ( $loc !== '' ) {
                                $urls[] = $loc;
                            }
                        }
                    }
                }
                libxml_clear_errors();
            }
        }

        $menu_urls = self::collect_menu_urls();
        if ( ! empty( $menu_urls ) ) {
            $urls = array_merge( $urls, $menu_urls );
        }

        $home_links = self::collect_homepage_links();
        if ( ! empty( $home_links ) ) {
            $urls = array_merge( $urls, $home_links );
        }

        $posts = get_posts( array(
            'post_type'      => array( 'page', 'post' ),
            'post_status'    => 'publish',
            'posts_per_page' => $limit,
            'fields'         => 'ids',
        ) );
        foreach ( $posts as $post_id ) {
            $permalink = get_permalink( $post_id );
            if ( $permalink ) {
                $urls[] = $permalink;
            }
        }

        if ( class_exists( 'WooCommerce' ) ) {
            $products = get_posts( array(
                'post_type'      => 'product',
                'post_status'    => 'publish',
                'posts_per_page' => $limit,
                'fields'         => 'ids',
            ) );
            foreach ( $products as $product_id ) {
                $permalink = get_permalink( $product_id );
                if ( $permalink ) {
                    $urls[] = $permalink;
                }
            }
        }

        $urls = array_values( array_unique( array_filter( $urls ) ) );
        if ( $limit <= 0 ) {
            $limit = 200;
        }

        return array_slice( $urls, 0, $limit );
    }

    private static function collect_menu_urls() {
        if ( ! function_exists( 'get_nav_menu_locations' ) ) {
            return array();
        }

        $locations = get_nav_menu_locations();
        if ( empty( $locations ) ) {
            return array();
        }

        $urls = array();
        foreach ( $locations as $location ) {
            $items = wp_get_nav_menu_items( $location );
            if ( empty( $items ) ) {
                continue;
            }
            foreach ( $items as $item ) {
                if ( empty( $item->url ) ) {
                    continue;
                }
                if ( self::is_internal_url( $item->url ) ) {
                    $urls[] = $item->url;
                }
            }
        }

        return $urls;
    }

    private static function collect_homepage_links() {
        if ( ! function_exists( 'wp_remote_get' ) ) {
            return array();
        }

        $response = wp_remote_get( home_url( '/' ), array( 'timeout' => 8 ) );
        if ( is_wp_error( $response ) ) {
            return array();
        }

        $html = wp_remote_retrieve_body( $response );
        if ( ! is_string( $html ) || $html === '' ) {
            return array();
        }

        if ( ! class_exists( 'DOMDocument' ) ) {
            return array();
        }

        libxml_use_internal_errors( true );
        $dom = new DOMDocument();
        $dom->loadHTML( '<?xml encoding="utf-8" ?>' . $html );
        libxml_clear_errors();

        $links = $dom->getElementsByTagName( 'a' );
        if ( ! $links || $links->length === 0 ) {
            return array();
        }

        $urls = array();
        foreach ( $links as $link ) {
            $href = $link->getAttribute( 'href' );
            if ( ! $href ) {
                continue;
            }
            if ( self::is_internal_url( $href ) ) {
                $urls[] = $href;
            }
        }

        return $urls;
    }

    private static function is_internal_url( $url ) {
        $home = wp_parse_url( home_url(), PHP_URL_HOST );
        if ( ! $home ) {
            return false;
        }
        $parts = wp_parse_url( $url );
        if ( empty( $parts['host'] ) ) {
            return true;
        }
        return strtolower( $parts['host'] ) === strtolower( $home );
    }

    public static function handle_gc() {
        $settings = get_option( self::OPTION_NAME, array() );
        if ( empty( $settings['enabled'] ) ) {
            return;
        }
        $ttl = isset( $settings['cache_ttl'] ) ? max( 60, intval( $settings['cache_ttl'] ) ) : 3600;
        self::garbage_collect( $ttl );
    }

    private static function schedule_gc() {
        if ( wp_next_scheduled( self::GC_HOOK ) ) {
            return;
        }
        wp_schedule_event( time() + 300, 'hourly', self::GC_HOOK );
    }

    private static function garbage_collect( $ttl ) {
        $dir = self::cache_base_dir();
        if ( ! is_dir( $dir ) ) {
            return;
        }

        $now = time();
        $iterator = new RecursiveIteratorIterator(
            new RecursiveDirectoryIterator( $dir, RecursiveDirectoryIterator::SKIP_DOTS ),
            RecursiveIteratorIterator::CHILD_FIRST
        );

        foreach ( $iterator as $item ) {
            if ( $item->isFile() ) {
                $mtime = $item->getMTime();
                if ( ( $now - $mtime ) > $ttl ) {
                    wp_delete_file( $item->getPathname() );
                }
            } elseif ( $item->isDir() ) {
                // phpcs:ignore
                @rmdir( $item->getPathname() );
            }
        }
    }

    private static function cache_base_dir() {
        $cache_dir = trailingslashit( WP_CONTENT_DIR ) . 'cache/auditor';
        return $cache_dir;
    }

    private static function cache_relative_path( $absolute ) {
        $abs = wp_normalize_path( $absolute );
        $root = wp_normalize_path( ABSPATH );
        if ( strpos( $abs, $root ) === 0 ) {
            return ltrim( substr( $abs, strlen( $root ) ), '/' );
        }

        $content = wp_normalize_path( WP_CONTENT_DIR );
        if ( strpos( $abs, $content ) === 0 ) {
            return ltrim( substr( $abs, strlen( $content ) ), '/' );
        }

        return ltrim( $abs, '/' );
    }

    private static function detect_server_type() {
        $software = isset( $_SERVER['SERVER_SOFTWARE'] ) ? strtolower( $_SERVER['SERVER_SOFTWARE'] ) : '';
        if ( $software !== '' ) {
            if ( strpos( $software, 'nginx' ) !== false ) {
                return 'nginx';
            }
            if ( strpos( $software, 'apache' ) !== false || strpos( $software, 'litespeed' ) !== false ) {
                return 'apache';
            }
        }

        return 'unknown';
    }

    private static function apache_rules_snippet() {
        $rules = array();
        $rules[] = '# BEGIN ' . self::BROWSER_CACHE_MARKER;
        $rules[] = '<IfModule mod_expires.c>';
        $rules[] = 'ExpiresActive On';
        $rules[] = 'ExpiresDefault "access plus 1 month"';
        $rules[] = 'ExpiresByType text/css "access plus 1 year"';
        $rules[] = 'ExpiresByType application/javascript "access plus 1 year"';
        $rules[] = 'ExpiresByType text/javascript "access plus 1 year"';
        $rules[] = 'ExpiresByType application/wasm "access plus 1 year"';
        $rules[] = 'ExpiresByType application/manifest+json "access plus 1 month"';
        $rules[] = 'ExpiresByType image/avif "access plus 1 year"';
        $rules[] = 'ExpiresByType image/webp "access plus 1 year"';
        $rules[] = 'ExpiresByType image/jpeg "access plus 1 year"';
        $rules[] = 'ExpiresByType image/png "access plus 1 year"';
        $rules[] = 'ExpiresByType image/gif "access plus 1 year"';
        $rules[] = 'ExpiresByType image/svg+xml "access plus 1 year"';
        $rules[] = 'ExpiresByType image/x-icon "access plus 1 year"';
        $rules[] = 'ExpiresByType image/bmp "access plus 1 year"';
        $rules[] = 'ExpiresByType image/tiff "access plus 1 year"';
        $rules[] = 'ExpiresByType font/woff2 "access plus 1 year"';
        $rules[] = 'ExpiresByType font/woff "access plus 1 year"';
        $rules[] = 'ExpiresByType application/font-woff "access plus 1 year"';
        $rules[] = 'ExpiresByType application/vnd.ms-fontobject "access plus 1 year"';
        $rules[] = 'ExpiresByType font/ttf "access plus 1 year"';
        $rules[] = 'ExpiresByType font/otf "access plus 1 year"';
        $rules[] = 'ExpiresByType audio/mpeg "access plus 1 year"';
        $rules[] = 'ExpiresByType audio/ogg "access plus 1 year"';
        $rules[] = 'ExpiresByType audio/wav "access plus 1 year"';
        $rules[] = 'ExpiresByType video/mp4 "access plus 1 year"';
        $rules[] = 'ExpiresByType video/webm "access plus 1 year"';
        $rules[] = 'ExpiresByType video/ogg "access plus 1 year"';
        $rules[] = 'ExpiresByType application/pdf "access plus 1 month"';
        $rules[] = 'ExpiresByType application/json "access plus 1 day"';
        $rules[] = 'ExpiresByType application/xml "access plus 1 day"';
        $rules[] = 'ExpiresByType text/xml "access plus 1 day"';
        $rules[] = 'ExpiresByType application/rss+xml "access plus 1 hour"';
        $rules[] = 'ExpiresByType application/atom+xml "access plus 1 hour"';
        $rules[] = '</IfModule>';
        $rules[] = '<IfModule mod_headers.c>';
        $rules[] = '<FilesMatch "\\.(?:avif|webp|jpe?g|png|gif|svg|ico|bmp|tiff?|css|js|mjs|wasm|woff2?|ttf|otf|eot|mp3|ogg|oga|wav|mp4|webm|ogv|webmanifest)$">';
        $rules[] = 'Header set Cache-Control "public, max-age=31536000, immutable"';
        $rules[] = '</FilesMatch>';
        $rules[] = '<FilesMatch "\\.(?:pdf|json|xml|rss|atom)$">';
        $rules[] = 'Header set Cache-Control "public, max-age=86400, must-revalidate"';
        $rules[] = '</FilesMatch>';
        $rules[] = '</IfModule>';
        $rules[] = '# END ' . self::BROWSER_CACHE_MARKER;

        return implode( "\n", $rules );
    }

    private static function nginx_rules_snippet() {
        $lines = array();
        $lines[] = 'location ~* \\.(?:avif|webp|jpe?g|png|gif|svg|ico|bmp|tiff?|css|js|mjs|wasm|woff2?|ttf|otf|eot|mp3|ogg|oga|wav|mp4|webm|ogv|webmanifest)$ {';
        $lines[] = '    expires 1y;';
        $lines[] = '    add_header Cache-Control "public, immutable";';
        $lines[] = '}';
        $lines[] = 'location ~* \\.(?:pdf|json|xml|rss|atom)$ {';
        $lines[] = '    expires 1d;';
        $lines[] = '    add_header Cache-Control "public, must-revalidate";';
        $lines[] = '}';
        return implode( "\n", $lines );
    }

    private static function maybe_write_apache_rules() {
        $settings = get_option( self::OPTION_NAME, array() );
        $server = isset( $settings['server_type'] ) ? $settings['server_type'] : '';
        if ( $server === '' ) {
            $server = self::detect_server_type();
        }
        if ( $server !== 'apache' ) {
            self::remove_apache_rules( true );
            return true;
        }

        $htaccess = trailingslashit( ABSPATH ) . '.htaccess';
        if ( file_exists( $htaccess ) ) {
            // phpcs:ignore
            if ( ! is_writable( $htaccess ) ) {
                return false;
            }
            $contents = file_get_contents( $htaccess );
            if ( false === $contents ) {
                return false;
            }
        } else {
            // phpcs:ignore
            if ( ! is_writable( dirname( $htaccess ) ) ) {
                return false;
            }
            $contents = '';
        }

        // Remove the old direct-delivery page-cache block. Cached HTML now goes
        // through WordPress so cookie, query-string, status-code, and TTL checks run.
        $contents = self::remove_marker_block( $contents, self::CACHE_MARKER );
        $browser_cache = ! array_key_exists( 'browser_cache', $settings ) || ! empty( $settings['browser_cache'] );
        if ( $browser_cache ) {
            $contents = self::replace_marker_block( $contents, self::apache_rules_snippet(), self::BROWSER_CACHE_MARKER );
        } else {
            $contents = self::remove_marker_block( $contents, self::BROWSER_CACHE_MARKER );
        }
        $written = file_put_contents( $htaccess, $contents );
        return $written !== false;
    }

    private static function remove_apache_rules( $include_browser = false ) {
        $htaccess = trailingslashit( ABSPATH ) . '.htaccess';
        // phpcs:ignore
        if ( ! file_exists( $htaccess ) || ! is_writable( $htaccess ) ) {
            return;
        }

        $contents = file_get_contents( $htaccess );
        if ( $contents === false ) {
            return;
        }

        $contents = self::remove_marker_block( $contents, self::CACHE_MARKER );
        if ( $include_browser ) {
            $contents = self::remove_marker_block( $contents, self::BROWSER_CACHE_MARKER );
        }
        file_put_contents( $htaccess, trim( $contents ) . "\n" );
    }

    private static function replace_marker_block( $contents, $block, $marker = '' ) {
        $marker = $marker ? $marker : self::CACHE_MARKER;
        $start = '# BEGIN ' . $marker;
        $end = '# END ' . $marker;
        $pattern = '/' . preg_quote( $start, '/' ) . '.*?' . preg_quote( $end, '/' ) . '\\s*/s';
        if ( preg_match( $pattern, $contents ) ) {
            return preg_replace( $pattern, $block . "\n", $contents );
        }

        return rtrim( $contents ) . "\n\n" . $block . "\n";
    }

    private static function remove_marker_block( $contents, $marker ) {
        $start = '# BEGIN ' . $marker;
        $end = '# END ' . $marker;
        $pattern = '/' . preg_quote( $start, '/' ) . '.*?' . preg_quote( $end, '/' ) . '\\s*/s';
        return preg_replace( $pattern, '', $contents );
    }

    private static function is_mobile_cache_enabled() {
        $settings = get_option( self::OPTION_NAME, array() );
        return ! empty( $settings['mobile_cache'] );
    }
}