HTML Examples/WP.iso/wordpress2/wp-includes/class-wp-customize-manager.php

PHP Script | 2018-01-30 | 192.6 KB | 5,702 lines

<?php
/**
 * WordPress Customize Manager classes
 *
 * @package WordPress
 * @subpackage Customize
 * @since 3.4.0
 */

/**
 * Customize Manager class.
 *
 * Bootstraps the Customize experience on the server-side.
 *
 * Sets up the theme-switching process if a theme other than the active one is
 * being previewed and customized.
 *
 * Serves as a factory for Customize Controls and Settings, and
 * instantiates default Customize Controls and Settings.
 *
 * @since 3.4.0
 */
final class WP_Customize_Manager {
    /**
     * An instance of the theme being previewed.
     *
     * @since 3.4.0
     * @var WP_Theme
     */
    protected $theme;

    /**
     * The directory name of the previously active theme (within the theme_root).
     *
     * @since 3.4.0
     * @var string
     */
    protected $original_stylesheet;

    /**
     * Whether this is a Customizer pageload.
     *
     * @since 3.4.0
     * @var bool
     */
    protected $previewing = false;

    /**
     * Methods and properties dealing with managing widgets in the Customizer.
     *
     * @since 3.9.0
     * @var WP_Customize_Widgets
     */
    public $widgets;

    /**
     * Methods and properties dealing with managing nav menus in the Customizer.
     *
     * @since 4.3.0
     * @var WP_Customize_Nav_Menus
     */
    public $nav_menus;

    /**
     * Methods and properties dealing with selective refresh in the Customizer preview.
     *
     * @since 4.5.0
     * @var WP_Customize_Selective_Refresh
     */
    public $selective_refresh;

    /**
     * Registered instances of WP_Customize_Setting.
     *
     * @since 3.4.0
     * @var array
     */
    protected $settings = array();

    /**
     * Sorted top-level instances of WP_Customize_Panel and WP_Customize_Section.
     *
     * @since 4.0.0
     * @var array
     */
    protected $containers = array();

    /**
     * Registered instances of WP_Customize_Panel.
     *
     * @since 4.0.0
     * @var array
     */
    protected $panels = array();

    /**
     * List of core components.
     *
     * @since 4.5.0
     * @var array
     */
    protected $components = array( 'widgets', 'nav_menus' );

    /**
     * Registered instances of WP_Customize_Section.
     *
     * @since 3.4.0
     * @var array
     */
    protected $sections = array();

    /**
     * Registered instances of WP_Customize_Control.
     *
     * @since 3.4.0
     * @var array
     */
    protected $controls = array();

    /**
     * Panel types that may be rendered from JS templates.
     *
     * @since 4.3.0
     * @var array
     */
    protected $registered_panel_types = array();

    /**
     * Section types that may be rendered from JS templates.
     *
     * @since 4.3.0
     * @var array
     */
    protected $registered_section_types = array();

    /**
     * Control types that may be rendered from JS templates.
     *
     * @since 4.1.0
     * @var array
     */
    protected $registered_control_types = array();

    /**
     * Initial URL being previewed.
     *
     * @since 4.4.0
     * @var string
     */
    protected $preview_url;

    /**
     * URL to link the user to when closing the Customizer.
     *
     * @since 4.4.0
     * @var string
     */
    protected $return_url;

    /**
     * Mapping of 'panel', 'section', 'control' to the ID which should be autofocused.
     *
     * @since 4.4.0
     * @var array
     */
    protected $autofocus = array();

    /**
     * Messenger channel.
     *
     * @since 4.7.0
     * @var string
     */
    protected $messenger_channel;

    /**
     * Whether the autosave revision of the changeset should be loaded.
     *
     * @since 4.9.0
     * @var bool
     */
    protected $autosaved = false;

    /**
     * Whether the changeset branching is allowed.
     *
     * @since 4.9.0
     * @var bool
     */
    protected $branching = true;

    /**
     * Whether settings should be previewed.
     *
     * @since 4.9.0
     * @var bool
     */
    protected $settings_previewed = true;

    /**
     * Whether a starter content changeset was saved.
     *
     * @since 4.9.0
     * @var bool
     */
    protected $saved_starter_content_changeset = false;

    /**
     * Unsanitized values for Customize Settings parsed from $_POST['customized'].
     *
     * @var array
     */
    private $_post_values;

    /**
     * Changeset UUID.
     *
     * @since 4.7.0
     * @var string
     */
    private $_changeset_uuid;

    /**
     * Changeset post ID.
     *
     * @since 4.7.0
     * @var int|false
     */
    private $_changeset_post_id;

    /**
     * Changeset data loaded from a customize_changeset post.
     *
     * @since 4.7.0
     * @var array
     */
    private $_changeset_data;

    /**
     * Constructor.
     *
     * @since 3.4.0
     * @since 4.7.0 Added $args param.
     *
     * @param array $args {
     *     Args.
     *
     *     @type null|string|false $changeset_uuid     Changeset UUID, the `post_name` for the customize_changeset post containing the customized state.
     *                                                 Defaults to `null` resulting in a UUID to be immediately generated. If `false` is provided, then
     *                                                 then the changeset UUID will be determined during `after_setup_theme`: when the
     *                                                 `customize_changeset_branching` filter returns false, then the default UUID will be that
     *                                                 of the most recent `customize_changeset` post that has a status other than 'auto-draft',
     *                                                 'publish', or 'trash'. Otherwise, if changeset branching is enabled, then a random UUID will be used.
     *     @type string            $theme              Theme to be previewed (for theme switch). Defaults to customize_theme or theme query params.
     *     @type string            $messenger_channel  Messenger channel. Defaults to customize_messenger_channel query param.
     *     @type bool              $settings_previewed If settings should be previewed. Defaults to true.
     *     @type bool              $branching          If changeset branching is allowed; otherwise, changesets are linear. Defaults to true.
     *     @type bool              $autosaved          If data from a changeset's autosaved revision should be loaded if it exists. Defaults to false.
     * }
     */
    public function __construct( $args = array() ) {

        $args = array_merge(
            array_fill_keys( array( 'changeset_uuid', 'theme', 'messenger_channel', 'settings_previewed', 'autosaved', 'branching' ), null ),
            $args
        );

        // Note that the UUID format will be validated in the setup_theme() method.
        if ( ! isset( $args['changeset_uuid'] ) ) {
            $args['changeset_uuid'] = wp_generate_uuid4();
        }

        // The theme and messenger_channel should be supplied via $args, but they are also looked at in the $_REQUEST global here for back-compat.
        if ( ! isset( $args['theme'] ) ) {
            if ( isset( $_REQUEST['customize_theme'] ) ) {
                $args['theme'] = wp_unslash( $_REQUEST['customize_theme'] );
            } elseif ( isset( $_REQUEST['theme'] ) ) { // Deprecated.
                $args['theme'] = wp_unslash( $_REQUEST['theme'] );
            }
        }
        if ( ! isset( $args['messenger_channel'] ) && isset( $_REQUEST['customize_messenger_channel'] ) ) {
            $args['messenger_channel'] = sanitize_key( wp_unslash( $_REQUEST['customize_messenger_channel'] ) );
        }

        $this->original_stylesheet = get_stylesheet();
        $this->theme = wp_get_theme( 0 === validate_file( $args['theme'] ) ? $args['theme'] : null );
        $this->messenger_channel = $args['messenger_channel'];
        $this->_changeset_uuid = $args['changeset_uuid'];

        foreach ( array( 'settings_previewed', 'autosaved', 'branching' ) as $key ) {
            if ( isset( $args[ $key ] ) ) {
                $this->$key = (bool) $args[ $key ];
            }
        }

        require_once( ABSPATH . WPINC . '/class-wp-customize-setting.php' );
        require_once( ABSPATH . WPINC . '/class-wp-customize-panel.php' );
        require_once( ABSPATH . WPINC . '/class-wp-customize-section.php' );
        require_once( ABSPATH . WPINC . '/class-wp-customize-control.php' );

        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-color-control.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-media-control.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-upload-control.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-image-control.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-background-image-control.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-background-position-control.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-cropped-image-control.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-site-icon-control.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-header-image-control.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-theme-control.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-code-editor-control.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-widget-area-customize-control.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-widget-form-customize-control.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-nav-menu-control.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-nav-menu-item-control.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-nav-menu-location-control.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-nav-menu-name-control.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-nav-menu-locations-control.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-nav-menu-auto-add-control.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-new-menu-control.php' ); // @todo Remove in 5.0. See #42364.

        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-nav-menus-panel.php' );

        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-themes-panel.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-themes-section.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-sidebar-section.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-nav-menu-section.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-new-menu-section.php' ); // @todo Remove in 5.0. See #42364.

        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-custom-css-setting.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-filter-setting.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-header-image-setting.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-background-image-setting.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-nav-menu-item-setting.php' );
        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-nav-menu-setting.php' );

        /**
         * Filters the core Customizer components to load.
         *
         * This allows Core components to be excluded from being instantiated by
         * filtering them out of the array. Note that this filter generally runs
         * during the {@see 'plugins_loaded'} action, so it cannot be added
         * in a theme.
         *
         * @since 4.4.0
         *
         * @see WP_Customize_Manager::__construct()
         *
         * @param array                $components List of core components to load.
         * @param WP_Customize_Manager $this       WP_Customize_Manager instance.
         */
        $components = apply_filters( 'customize_loaded_components', $this->components, $this );

        require_once( ABSPATH . WPINC . '/customize/class-wp-customize-selective-refresh.php' );
        $this->selective_refresh = new WP_Customize_Selective_Refresh( $this );

        if ( in_array( 'widgets', $components, true ) ) {
            require_once( ABSPATH . WPINC . '/class-wp-customize-widgets.php' );
            $this->widgets = new WP_Customize_Widgets( $this );
        }

        if ( in_array( 'nav_menus', $components, true ) ) {
            require_once( ABSPATH . WPINC . '/class-wp-customize-nav-menus.php' );
            $this->nav_menus = new WP_Customize_Nav_Menus( $this );
        }

        add_action( 'setup_theme', array( $this, 'setup_theme' ) );
        add_action( 'wp_loaded',   array( $this, 'wp_loaded' ) );

        // Do not spawn cron (especially the alternate cron) while running the Customizer.
        remove_action( 'init', 'wp_cron' );

        // Do not run update checks when rendering the controls.
        remove_action( 'admin_init', '_maybe_update_core' );
        remove_action( 'admin_init', '_maybe_update_plugins' );
        remove_action( 'admin_init', '_maybe_update_themes' );

        add_action( 'wp_ajax_customize_save',                     array( $this, 'save' ) );
        add_action( 'wp_ajax_customize_trash',                    array( $this, 'handle_changeset_trash_request' ) );
        add_action( 'wp_ajax_customize_refresh_nonces',           array( $this, 'refresh_nonces' ) );
        add_action( 'wp_ajax_customize_load_themes',              array( $this, 'handle_load_themes_request' ) );
        add_filter( 'heartbeat_settings',                         array( $this, 'add_customize_screen_to_heartbeat_settings' ) );
        add_filter( 'heartbeat_received',                         array( $this, 'check_changeset_lock_with_heartbeat' ), 10, 3 );
        add_action( 'wp_ajax_customize_override_changeset_lock',  array( $this, 'handle_override_changeset_lock_request' ) );
        add_action( 'wp_ajax_customize_dismiss_autosave_or_lock', array( $this, 'handle_dismiss_autosave_or_lock_request' ) );

        add_action( 'customize_register',                 array( $this, 'register_controls' ) );
        add_action( 'customize_register',                 array( $this, 'register_dynamic_settings' ), 11 ); // allow code to create settings first
        add_action( 'customize_controls_init',            array( $this, 'prepare_controls' ) );
        add_action( 'customize_controls_enqueue_scripts', array( $this, 'enqueue_control_scripts' ) );

        // Render Common, Panel, Section, and Control templates.
        add_action( 'customize_controls_print_footer_scripts', array( $this, 'render_panel_templates' ), 1 );
        add_action( 'customize_controls_print_footer_scripts', array( $this, 'render_section_templates' ), 1 );
        add_action( 'customize_controls_print_footer_scripts', array( $this, 'render_control_templates' ), 1 );

        // Export header video settings with the partial response.
        add_filter( 'customize_render_partials_response', array( $this, 'export_header_video_settings' ), 10, 3 );

        // Export the settings to JS via the _wpCustomizeSettings variable.
        add_action( 'customize_controls_print_footer_scripts', array( $this, 'customize_pane_settings' ), 1000 );

        // Add theme update notices.
        if ( current_user_can( 'install_themes' ) || current_user_can( 'update_themes' ) ) {
            require_once ABSPATH . '/wp-admin/includes/update.php';
            add_action( 'customize_controls_print_footer_scripts', 'wp_print_admin_notice_templates' );
        }
    }

    /**
     * Return true if it's an Ajax request.
     *
     * @since 3.4.0
     * @since 4.2.0 Added `$action` param.
     *
     * @param string|null $action Whether the supplied Ajax action is being run.
     * @return bool True if it's an Ajax request, false otherwise.
     */
    public function doing_ajax( $action = null ) {
        if ( ! wp_doing_ajax() ) {
            return false;
        }

        if ( ! $action ) {
            return true;
        } else {
            /*
             * Note: we can't just use doing_action( "wp_ajax_{$action}" ) because we need
             * to check before admin-ajax.php gets to that point.
             */
            return isset( $_REQUEST['action'] ) && wp_unslash( $_REQUEST['action'] ) === $action;
        }
    }

    /**
     * Custom wp_die wrapper. Returns either the standard message for UI
     * or the Ajax message.
     *
     * @since 3.4.0
     *
     * @param mixed $ajax_message Ajax return
     * @param mixed $message UI message
     */
    protected function wp_die( $ajax_message, $message = null ) {
        if ( $this->doing_ajax() ) {
            wp_die( $ajax_message );
        }

        if ( ! $message ) {
            $message = __( 'Cheatin’ uh?' );
        }

        if ( $this->messenger_channel ) {
            ob_start();
            wp_enqueue_scripts();
            wp_print_scripts( array( 'customize-base' ) );

            $settings = array(
                'messengerArgs' => array(
                    'channel' => $this->messenger_channel,
                    'url' => wp_customize_url(),
                ),
                'error' => $ajax_message,
            );
            ?>
            <script>
            ( function( api, settings ) {
                var preview = new api.Messenger( settings.messengerArgs );
                preview.send( 'iframe-loading-error', settings.error );
            } )( wp.customize, <?php echo wp_json_encode( $settings ) ?> );
            </script>
            <?php
            $message .= ob_get_clean();
        }

        wp_die( $message );
    }

    /**
     * Return the Ajax wp_die() handler if it's a customized request.
     *
     * @since 3.4.0
     * @deprecated 4.7.0
     *
     * @return callable Die handler.
     */
    public function wp_die_handler() {
        _deprecated_function( __METHOD__, '4.7.0' );

        if ( $this->doing_ajax() || isset( $_POST['customized'] ) ) {
            return '_ajax_wp_die_handler';
        }

        return '_default_wp_die_handler';
    }

    /**
     * Start preview and customize theme.
     *
     * Check if customize query variable exist. Init filters to filter the current theme.
     *
     * @since 3.4.0
     *
     * @global string $pagenow
     */
    public function setup_theme() {
        global $pagenow;

        // Check permissions for customize.php access since this method is called before customize.php can run any code,
        if ( 'customize.php' === $pagenow && ! current_user_can( 'customize' ) ) {
            if ( ! is_user_logged_in() ) {
                auth_redirect();
            } else {
                wp_die(
                    '<h1>' . __( 'Cheatin’ uh?' ) . '</h1>' .
                    '<p>' . __( 'Sorry, you are not allowed to customize this site.' ) . '</p>',
                    403
                );
            }
            return;
        }

        // If a changeset was provided is invalid.
        if ( isset( $this->_changeset_uuid ) && false !== $this->_changeset_uuid && ! wp_is_uuid( $this->_changeset_uuid ) ) {
            $this->wp_die( -1, __( 'Invalid changeset UUID' ) );
        }

        /*
         * Clear incoming post data if the user lacks a CSRF token (nonce). Note that the customizer
         * application will inject the customize_preview_nonce query parameter into all Ajax requests.
         * For similar behavior elsewhere in WordPress, see rest_cookie_check_errors() which logs out
         * a user when a valid nonce isn't present.
         */
        $has_post_data_nonce = (
            check_ajax_referer( 'preview-customize_' . $this->get_stylesheet(), 'nonce', false )
            ||
            check_ajax_referer( 'save-customize_' . $this->get_stylesheet(), 'nonce', false )
            ||
            check_ajax_referer( 'preview-customize_' . $this->get_stylesheet(), 'customize_preview_nonce', false )
        );
        if ( ! current_user_can( 'customize' ) || ! $has_post_data_nonce ) {
            unset( $_POST['customized'] );
            unset( $_REQUEST['customized'] );
        }

        /*
         * If unauthenticated then require a valid changeset UUID to load the preview.
         * In this way, the UUID serves as a secret key. If the messenger channel is present,
         * then send unauthenticated code to prompt re-auth.
         */
        if ( ! current_user_can( 'customize' ) && ! $this->changeset_post_id() ) {
            $this->wp_die( $this->messenger_channel ? 0 : -1, __( 'Non-existent changeset UUID.' ) );
        }

        if ( ! headers_sent() ) {
            send_origin_headers();
        }

        // Hide the admin bar if we're embedded in the customizer iframe.
        if ( $this->messenger_channel ) {
            show_admin_bar( false );
        }

        if ( $this->is_theme_active() ) {
            // Once the theme is loaded, we'll validate it.
            add_action( 'after_setup_theme', array( $this, 'after_setup_theme' ) );
        } else {
            // If the requested theme is not the active theme and the user doesn't have the
            // switch_themes cap, bail.
            if ( ! current_user_can( 'switch_themes' ) ) {
                $this->wp_die( -1, __( 'Sorry, you are not allowed to edit theme options on this site.' ) );
            }

            // If the theme has errors while loading, bail.
            if ( $this->theme()->errors() ) {
                $this->wp_die( -1, $this->theme()->errors()->get_error_message() );
            }

            // If the theme isn't allowed per multisite settings, bail.
            if ( ! $this->theme()->is_allowed() ) {
                $this->wp_die( -1, __( 'The requested theme does not exist.' ) );
            }
        }

        // Make sure changeset UUID is established immediately after the theme is loaded.
        add_action( 'after_setup_theme', array( $this, 'establish_loaded_changeset' ), 5 );

        /*
         * Import theme starter content for fresh installations when landing in the customizer.
         * Import starter content at after_setup_theme:100 so that any
         * add_theme_support( 'starter-content' ) calls will have been made.
         */
        if ( get_option( 'fresh_site' ) && 'customize.php' === $pagenow ) {
            add_action( 'after_setup_theme', array( $this, 'import_theme_starter_content' ), 100 );
        }

        $this->start_previewing_theme();
    }

    /**
     * Establish the loaded changeset.
     *
     * This method runs right at after_setup_theme and applies the 'customize_changeset_branching' filter to determine
     * whether concurrent changesets are allowed. Then if the Customizer is not initialized with a `changeset_uuid` param,
     * this method will determine which UUID should be used. If changeset branching is disabled, then the most saved
     * changeset will be loaded by default. Otherwise, if there are no existing saved changesets or if changeset branching is
     * enabled, then a new UUID will be generated.
     *
     * @since 4.9.0
     * @global string $pagenow
     */
    public function establish_loaded_changeset() {
        global $pagenow;

        if ( empty( $this->_changeset_uuid ) ) {
            $changeset_uuid = null;

            if ( ! $this->branching() && $this->is_theme_active() ) {
                $unpublished_changeset_posts = $this->get_changeset_posts( array(
                    'post_status' => array_diff( get_post_stati(), array( 'auto-draft', 'publish', 'trash', 'inherit', 'private' ) ),
                    'exclude_restore_dismissed' => false,
                    'author' => 'any',
                    'posts_per_page' => 1,
                    'order' => 'DESC',
                    'orderby' => 'date',
                ) );
                $unpublished_changeset_post = array_shift( $unpublished_changeset_posts );
                if ( ! empty( $unpublished_changeset_post ) && wp_is_uuid( $unpublished_changeset_post->post_name ) ) {
                    $changeset_uuid = $unpublished_changeset_post->post_name;
                }
            }

            // If no changeset UUID has been set yet, then generate a new one.
            if ( empty( $changeset_uuid ) ) {
                $changeset_uuid = wp_generate_uuid4();
            }

            $this->_changeset_uuid = $changeset_uuid;
        }

        if ( is_admin() && 'customize.php' === $pagenow ) {
            $this->set_changeset_lock( $this->changeset_post_id() );
        }
    }

    /**
     * Callback to validate a theme once it is loaded
     *
     * @since 3.4.0
     */
    public function after_setup_theme() {
        $doing_ajax_or_is_customized = ( $this->doing_ajax() || isset( $_POST['customized'] ) );
        if ( ! $doing_ajax_or_is_customized && ! validate_current_theme() ) {
            wp_redirect( 'themes.php?broken=true' );
            exit;
        }
    }

    /**
     * If the theme to be previewed isn't the active theme, add filter callbacks
     * to swap it out at runtime.
     *
     * @since 3.4.0
     */
    public function start_previewing_theme() {
        // Bail if we're already previewing.
        if ( $this->is_preview() ) {
            return;
        }

        $this->previewing = true;

        if ( ! $this->is_theme_active() ) {
            add_filter( 'template', array( $this, 'get_template' ) );
            add_filter( 'stylesheet', array( $this, 'get_stylesheet' ) );
            add_filter( 'pre_option_current_theme', array( $this, 'current_theme' ) );

            // @link: https://core.trac.wordpress.org/ticket/20027
            add_filter( 'pre_option_stylesheet', array( $this, 'get_stylesheet' ) );
            add_filter( 'pre_option_template', array( $this, 'get_template' ) );

            // Handle custom theme roots.
            add_filter( 'pre_option_stylesheet_root', array( $this, 'get_stylesheet_root' ) );
            add_filter( 'pre_option_template_root', array( $this, 'get_template_root' ) );
        }

        /**
         * Fires once the Customizer theme preview has started.
         *
         * @since 3.4.0
         *
         * @param WP_Customize_Manager $this WP_Customize_Manager instance.
         */
        do_action( 'start_previewing_theme', $this );
    }

    /**
     * Stop previewing the selected theme.
     *
     * Removes filters to change the current theme.
     *
     * @since 3.4.0
     */
    public function stop_previewing_theme() {
        if ( ! $this->is_preview() ) {
            return;
        }

        $this->previewing = false;

        if ( ! $this->is_theme_active() ) {
            remove_filter( 'template', array( $this, 'get_template' ) );
            remove_filter( 'stylesheet', array( $this, 'get_stylesheet' ) );
            remove_filter( 'pre_option_current_theme', array( $this, 'current_theme' ) );

            // @link: https://core.trac.wordpress.org/ticket/20027
            remove_filter( 'pre_option_stylesheet', array( $this, 'get_stylesheet' ) );
            remove_filter( 'pre_option_template', array( $this, 'get_template' ) );

            // Handle custom theme roots.
            remove_filter( 'pre_option_stylesheet_root', array( $this, 'get_stylesheet_root' ) );
            remove_filter( 'pre_option_template_root', array( $this, 'get_template_root' ) );
        }

        /**
         * Fires once the Customizer theme preview has stopped.
         *
         * @since 3.4.0
         *
         * @param WP_Customize_Manager $this WP_Customize_Manager instance.
         */
        do_action( 'stop_previewing_theme', $this );
    }

    /**
     * Gets whether settings are or will be previewed.
     *
     * @since 4.9.0
     * @see WP_Customize_Setting::preview()
     *
     * @return bool
     */
    public function settings_previewed() {
        return $this->settings_previewed;
    }

    /**
     * Gets whether data from a changeset's autosaved revision should be loaded if it exists.
     *
     * @since 4.9.0
     * @see WP_Customize_Manager::changeset_data()
     *
     * @return bool Is using autosaved changeset revision.
     */
    public function autosaved() {
        return $this->autosaved;
    }

    /**
     * Whether the changeset branching is allowed.
     *
     * @since 4.9.0
     * @see WP_Customize_Manager::establish_loaded_changeset()
     *
     * @return bool Is changeset branching.
     */
    public function branching() {

        /**
         * Filters whether or not changeset branching is allowed.
         *
         * By default in core, when changeset branching is not allowed, changesets will operate
         * linearly in that only one saved changeset will exist at a time (with a 'draft' or
         * 'future' status). This makes the Customizer operate in a way that is similar to going to
         * "edit" to one existing post: all users will be making changes to the same post, and autosave
         * revisions will be made for that post.
         *
         * By contrast, when changeset branching is allowed, then the model is like users going
         * to "add new" for a page and each user makes changes independently of each other since
         * they are all operating on their own separate pages, each getting their own separate
         * initial auto-drafts and then once initially saved, autosave revisions on top of that
         * user's specific post.
         *
         * Since linear changesets are deemed to be more suitable for the majority of WordPress users,
         * they are the default. For WordPress sites that have heavy site management in the Customizer
         * by multiple users then branching changesets should be enabled by means of this filter.
         *
         * @since 4.9.0
         *
         * @param bool                 $allow_branching Whether branching is allowed. If `false`, the default,
         *                                              then only one saved changeset exists at a time.
         * @param WP_Customize_Manager $wp_customize    Manager instance.
         */
        $this->branching = apply_filters( 'customize_changeset_branching', $this->branching, $this );

        return $this->branching;
    }

    /**
     * Get the changeset UUID.
     *
     * @since 4.7.0
     * @see WP_Customize_Manager::establish_loaded_changeset()
     *
     * @return string UUID.
     */
    public function changeset_uuid() {
        if ( empty( $this->_changeset_uuid ) ) {
            $this->establish_loaded_changeset();
        }
        return $this->_changeset_uuid;
    }

    /**
     * Get the theme being customized.
     *
     * @since 3.4.0
     *
     * @return WP_Theme
     */
    public function theme() {
        if ( ! $this->theme ) {
            $this->theme = wp_get_theme();
        }
        return $this->theme;
    }

    /**
     * Get the registered settings.
     *
     * @since 3.4.0
     *
     * @return array
     */
    public function settings() {
        return $this->settings;
    }

    /**
     * Get the registered controls.
     *
     * @since 3.4.0
     *
     * @return array
     */
    public function controls() {
        return $this->controls;
    }

    /**
     * Get the registered containers.
     *
     * @since 4.0.0
     *
     * @return array
     */
    public function containers() {
        return $this->containers;
    }

    /**
     * Get the registered sections.
     *
     * @since 3.4.0
     *
     * @return array
     */
    public function sections() {
        return $this->sections;
    }

    /**
     * Get the registered panels.
     *
     * @since 4.0.0
     *
     * @return array Panels.
     */
    public function panels() {
        return $this->panels;
    }

    /**
     * Checks if the current theme is active.
     *
     * @since 3.4.0
     *
     * @return bool
     */
    public function is_theme_active() {
        return $this->get_stylesheet() == $this->original_stylesheet;
    }

    /**
     * Register styles/scripts and initialize the preview of each setting
     *
     * @since 3.4.0
     */
    public function wp_loaded() {

        // Unconditionally register core types for panels, sections, and controls in case plugin unhooks all customize_register actions.
        $this->register_panel_type( 'WP_Customize_Panel' );
        $this->register_panel_type( 'WP_Customize_Themes_Panel' );
        $this->register_section_type( 'WP_Customize_Section' );
        $this->register_section_type( 'WP_Customize_Sidebar_Section' );
        $this->register_section_type( 'WP_Customize_Themes_Section' );
        $this->register_control_type( 'WP_Customize_Color_Control' );
        $this->register_control_type( 'WP_Customize_Media_Control' );
        $this->register_control_type( 'WP_Customize_Upload_Control' );
        $this->register_control_type( 'WP_Customize_Image_Control' );
        $this->register_control_type( 'WP_Customize_Background_Image_Control' );
        $this->register_control_type( 'WP_Customize_Background_Position_Control' );
        $this->register_control_type( 'WP_Customize_Cropped_Image_Control' );
        $this->register_control_type( 'WP_Customize_Site_Icon_Control' );
        $this->register_control_type( 'WP_Customize_Theme_Control' );
        $this->register_control_type( 'WP_Customize_Code_Editor_Control' );
        $this->register_control_type( 'WP_Customize_Date_Time_Control' );

        /**
         * Fires once WordPress has loaded, allowing scripts and styles to be initialized.
         *
         * @since 3.4.0
         *
         * @param WP_Customize_Manager $this WP_Customize_Manager instance.
         */
        do_action( 'customize_register', $this );

        if ( $this->settings_previewed() ) {
            foreach ( $this->settings as $setting ) {
                $setting->preview();
            }
        }

        if ( $this->is_preview() && ! is_admin() ) {
            $this->customize_preview_init();
        }
    }

    /**
     * Prevents Ajax requests from following redirects when previewing a theme
     * by issuing a 200 response instead of a 30x.
     *
     * Instead, the JS will sniff out the location header.
     *
     * @since 3.4.0
     * @deprecated 4.7.0
     *
     * @param int $status Status.
     * @return int
     */
    public function wp_redirect_status( $status ) {
        _deprecated_function( __FUNCTION__, '4.7.0' );

        if ( $this->is_preview() && ! is_admin() ) {
            return 200;
        }

        return $status;
    }

    /**
     * Find the changeset post ID for a given changeset UUID.
     *
     * @since 4.7.0
     *
     * @param string $uuid Changeset UUID.
     * @return int|null Returns post ID on success and null on failure.
     */
    public function find_changeset_post_id( $uuid ) {
        $cache_group = 'customize_changeset_post';
        $changeset_post_id = wp_cache_get( $uuid, $cache_group );
        if ( $changeset_post_id && 'customize_changeset' === get_post_type( $changeset_post_id ) ) {
            return $changeset_post_id;
        }

        $changeset_post_query = new WP_Query( array(
            'post_type' => 'customize_changeset',
            'post_status' => get_post_stati(),
            'name' => $uuid,
            'posts_per_page' => 1,
            'no_found_rows' => true,
            'cache_results' => true,
            'update_post_meta_cache' => false,
            'update_post_term_cache' => false,
            'lazy_load_term_meta' => false,
        ) );
        if ( ! empty( $changeset_post_query->posts ) ) {
            // Note: 'fields'=>'ids' is not being used in order to cache the post object as it will be needed.
            $changeset_post_id = $changeset_post_query->posts[0]->ID;
            wp_cache_set( $uuid, $changeset_post_id, $cache_group );
            return $changeset_post_id;
        }

        return null;
    }

    /**
     * Get changeset posts.
     *
     * @since 4.9.0
     *
     * @param array $args {
     *     Args to pass into `get_posts()` to query changesets.
     *
     *     @type int    $posts_per_page             Number of posts to return. Defaults to -1 (all posts).
     *     @type int    $author                     Post author. Defaults to current user.
     *     @type string $post_status                Status of changeset. Defaults to 'auto-draft'.
     *     @type bool   $exclude_restore_dismissed  Whether to exclude changeset auto-drafts that have been dismissed. Defaults to true.
     * }
     * @return WP_Post[] Auto-draft changesets.
     */
    protected function get_changeset_posts( $args = array() ) {
        $default_args = array(
            'exclude_restore_dismissed' => true,
            'posts_per_page' => -1,
            'post_type' => 'customize_changeset',
            'post_status' => 'auto-draft',
            'order' => 'DESC',
            'orderby' => 'date',
            'no_found_rows' => true,
            'cache_results' => true,
            'update_post_meta_cache' => false,
            'update_post_term_cache' => false,
            'lazy_load_term_meta' => false,
        );
        if ( get_current_user_id() ) {
            $default_args['author'] = get_current_user_id();
        }
        $args = array_merge( $default_args, $args );

        if ( ! empty( $args['exclude_restore_dismissed'] ) ) {
            unset( $args['exclude_restore_dismissed'] );
            $args['meta_query'] = array(
                array(
                    'key' => '_customize_restore_dismissed',
                    'compare' => 'NOT EXISTS',
                ),
            );
        }

        return get_posts( $args );
    }

    /**
     * Dismiss all of the current user's auto-drafts (other than the present one).
     *
     * @since 4.9.0
     * @return int The number of auto-drafts that were dismissed.
     */
    protected function dismiss_user_auto_draft_changesets() {
        $changeset_autodraft_posts = $this->get_changeset_posts( array(
            'post_status' => 'auto-draft',
            'exclude_restore_dismissed' => true,
            'posts_per_page' => -1,
        ) );
        $dismissed = 0;
        foreach ( $changeset_autodraft_posts as $autosave_autodraft_post ) {
            if ( $autosave_autodraft_post->ID === $this->changeset_post_id() ) {
                continue;
            }
            if ( update_post_meta( $autosave_autodraft_post->ID, '_customize_restore_dismissed', true ) ) {
                $dismissed++;
            }
        }
        return $dismissed;
    }

    /**
     * Get the changeset post id for the loaded changeset.
     *
     * @since 4.7.0
     *
     * @return int|null Post ID on success or null if there is no post yet saved.
     */
    public function changeset_post_id() {
        if ( ! isset( $this->_changeset_post_id ) ) {
            $post_id = $this->find_changeset_post_id( $this->changeset_uuid() );
            if ( ! $post_id ) {
                $post_id = false;
            }
            $this->_changeset_post_id = $post_id;
        }
        if ( false === $this->_changeset_post_id ) {
            return null;
        }
        return $this->_changeset_post_id;
    }

    /**
     * Get the data stored in a changeset post.
     *
     * @since 4.7.0
     *
     * @param int $post_id Changeset post ID.
     * @return array|WP_Error Changeset data or WP_Error on error.
     */
    protected function get_changeset_post_data( $post_id ) {
        if ( ! $post_id ) {
            return new WP_Error( 'empty_post_id' );
        }
        $changeset_post = get_post( $post_id );
        if ( ! $changeset_post ) {
            return new WP_Error( 'missing_post' );
        }
        if ( 'revision' === $changeset_post->post_type ) {
            if ( 'customize_changeset' !== get_post_type( $changeset_post->post_parent ) ) {
                return new WP_Error( 'wrong_post_type' );
            }
        } elseif ( 'customize_changeset' !== $changeset_post->post_type ) {
            return new WP_Error( 'wrong_post_type' );
        }
        $changeset_data = json_decode( $changeset_post->post_content, true );
        if ( function_exists( 'json_last_error' ) && json_last_error() ) {
            return new WP_Error( 'json_parse_error', '', json_last_error() );
        }
        if ( ! is_array( $changeset_data ) ) {
            return new WP_Error( 'expected_array' );
        }
        return $changeset_data;
    }

    /**
     * Get changeset data.
     *
     * @since 4.7.0
     * @since 4.9.0 This will return the changeset's data with a user's autosave revision merged on top, if one exists and $autosaved is true.
     *
     * @return array Changeset data.
     */
    public function changeset_data() {
        if ( isset( $this->_changeset_data ) ) {
            return $this->_changeset_data;
        }
        $changeset_post_id = $this->changeset_post_id();
        if ( ! $changeset_post_id ) {
            $this->_changeset_data = array();
        } else {
            if ( $this->autosaved() && is_user_logged_in() ) {
                $autosave_post = wp_get_post_autosave( $changeset_post_id, get_current_user_id() );
                if ( $autosave_post ) {
                    $data = $this->get_changeset_post_data( $autosave_post->ID );
                    if ( ! is_wp_error( $data ) ) {
                        $this->_changeset_data = $data;
                    }
                }
            }

            // Load data from the changeset if it was not loaded from an autosave.
            if ( ! isset( $this->_changeset_data ) ) {
                $data = $this->get_changeset_post_data( $changeset_post_id );
                if ( ! is_wp_error( $data ) ) {
                    $this->_changeset_data = $data;
                } else {
                    $this->_changeset_data = array();
                }
            }
        }
        return $this->_changeset_data;
    }

    /**
     * Starter content setting IDs.
     *
     * @since 4.7.0
     * @var array
     */
    protected $pending_starter_content_settings_ids = array();

    /**
     * Import theme starter content into the customized state.
     *
     * @since 4.7.0
     *
     * @param array $starter_content Starter content. Defaults to `get_theme_starter_content()`.
     */
    function import_theme_starter_content( $starter_content = array() ) {
        if ( empty( $starter_content ) ) {
            $starter_content = get_theme_starter_content();
        }

        $changeset_data = array();
        if ( $this->changeset_post_id() ) {
            /*
             * Don't re-import starter content into a changeset saved persistently.
             * This will need to be revisited in the future once theme switching
             * is allowed with drafted/scheduled changesets, since switching to
             * another theme could result in more starter content being applied.
             * However, when doing an explicit save it is currently possible for
             * nav menus and nav menu items specifically to lose their starter_content
             * flags, thus resulting in duplicates being created since they fail
             * to get re-used. See #40146.
             */
            if ( 'auto-draft' !== get_post_status( $this->changeset_post_id() ) ) {
                return;
            }

            $changeset_data = $this->get_changeset_post_data( $this->changeset_post_id() );
        }

        $sidebars_widgets = isset( $starter_content['widgets'] ) && ! empty( $this->widgets ) ? $starter_content['widgets'] : array();
        $attachments = isset( $starter_content['attachments'] ) && ! empty( $this->nav_menus ) ? $starter_content['attachments'] : array();
        $posts = isset( $starter_content['posts'] ) && ! empty( $this->nav_menus ) ? $starter_content['posts'] : array();
        $options = isset( $starter_content['options'] ) ? $starter_content['options'] : array();
        $nav_menus = isset( $starter_content['nav_menus'] ) && ! empty( $this->nav_menus ) ? $starter_content['nav_menus'] : array();
        $theme_mods = isset( $starter_content['theme_mods'] ) ? $starter_content['theme_mods'] : array();

        // Widgets.
        $max_widget_numbers = array();
        foreach ( $sidebars_widgets as $sidebar_id => $widgets ) {
            $sidebar_widget_ids = array();
            foreach ( $widgets as $widget ) {
                list( $id_base, $instance ) = $widget;

                if ( ! isset( $max_widget_numbers[ $id_base ] ) ) {

                    // When $settings is an array-like object, get an intrinsic array for use with array_keys().
                    $settings = get_option( "widget_{$id_base}", array() );
                    if ( $settings instanceof ArrayObject || $settings instanceof ArrayIterator ) {
                        $settings = $settings->getArrayCopy();
                    }

                    // Find the max widget number for this type.
                    $widget_numbers = array_keys( $settings );
                    if ( count( $widget_numbers ) > 0 ) {
                        $widget_numbers[] = 1;
                        $max_widget_numbers[ $id_base ] = call_user_func_array( 'max', $widget_numbers );
                    } else {
                        $max_widget_numbers[ $id_base ] = 1;
                    }
                }
                $max_widget_numbers[ $id_base ] += 1;

                $widget_id = sprintf( '%s-%d', $id_base, $max_widget_numbers[ $id_base ] );
                $setting_id = sprintf( 'widget_%s[%d]', $id_base, $max_widget_numbers[ $id_base ] );

                $setting_value = $this->widgets->sanitize_widget_js_instance( $instance );
                if ( empty( $changeset_data[ $setting_id ] ) || ! empty( $changeset_data[ $setting_id ]['starter_content'] ) ) {
                    $this->set_post_value( $setting_id, $setting_value );
                    $this->pending_starter_content_settings_ids[] = $setting_id;
                }
                $sidebar_widget_ids[] = $widget_id;
            }

            $setting_id = sprintf( 'sidebars_widgets[%s]', $sidebar_id );
            if ( empty( $changeset_data[ $setting_id ] ) || ! empty( $changeset_data[ $setting_id ]['starter_content'] ) ) {
                $this->set_post_value( $setting_id, $sidebar_widget_ids );
                $this->pending_starter_content_settings_ids[] = $setting_id;
            }
        }

        $starter_content_auto_draft_post_ids = array();
        if ( ! empty( $changeset_data['nav_menus_created_posts']['value'] ) ) {
            $starter_content_auto_draft_post_ids = array_merge( $starter_content_auto_draft_post_ids, $changeset_data['nav_menus_created_posts']['value'] );
        }

        // Make an index of all the posts needed and what their slugs are.
        $needed_posts = array();
        $attachments = $this->prepare_starter_content_attachments( $attachments );
        foreach ( $attachments as $attachment ) {
            $key = 'attachment:' . $attachment['post_name'];
            $needed_posts[ $key ] = true;
        }
        foreach ( array_keys( $posts ) as $post_symbol ) {
            if ( empty( $posts[ $post_symbol ]['post_name'] ) && empty( $posts[ $post_symbol ]['post_title'] ) ) {
                unset( $posts[ $post_symbol ] );
                continue;
            }
            if ( empty( $posts[ $post_symbol ]['post_name'] ) ) {
                $posts[ $post_symbol ]['post_name'] = sanitize_title( $posts[ $post_symbol ]['post_title'] );
            }
            if ( empty( $posts[ $post_symbol ]['post_type'] ) ) {
                $posts[ $post_symbol ]['post_type'] = 'post';
            }
            $needed_posts[ $posts[ $post_symbol ]['post_type'] . ':' . $posts[ $post_symbol ]['post_name'] ] = true;
        }
        $all_post_slugs = array_merge(
            wp_list_pluck( $attachments, 'post_name' ),
            wp_list_pluck( $posts, 'post_name' )
        );

        /*
         * Obtain all post types referenced in starter content to use in query.
         * This is needed because 'any' will not account for post types not yet registered.
         */
        $post_types = array_filter( array_merge( array( 'attachment' ), wp_list_pluck( $posts, 'post_type' ) ) );

        // Re-use auto-draft starter content posts referenced in the current customized state.
        $existing_starter_content_posts = array();
        if ( ! empty( $starter_content_auto_draft_post_ids ) ) {
            $existing_posts_query = new WP_Query( array(
                'post__in' => $starter_content_auto_draft_post_ids,
                'post_status' => 'auto-draft',
                'post_type' => $post_types,
                'posts_per_page' => -1,
            ) );
            foreach ( $existing_posts_query->posts as $existing_post ) {
                $post_name = $existing_post->post_name;
                if ( empty( $post_name ) ) {
                    $post_name = get_post_meta( $existing_post->ID, '_customize_draft_post_name', true );
                }
                $existing_starter_content_posts[ $existing_post->post_type . ':' . $post_name ] = $existing_post;
            }
        }

        // Re-use non-auto-draft posts.
        if ( ! empty( $all_post_slugs ) ) {
            $existing_posts_query = new WP_Query( array(
                'post_name__in' => $all_post_slugs,
                'post_status' => array_diff( get_post_stati(), array( 'auto-draft' ) ),
                'post_type' => 'any',
                'posts_per_page' => -1,
            ) );
            foreach ( $existing_posts_query->posts as $existing_post ) {
                $key = $existing_post->post_type . ':' . $existing_post->post_name;
                if ( isset( $needed_posts[ $key ] ) && ! isset( $existing_starter_content_posts[ $key ] ) ) {
                    $existing_starter_content_posts[ $key ] = $existing_post;
                }
            }
        }

        // Attachments are technically posts but handled differently.
        if ( ! empty( $attachments ) ) {

            $attachment_ids = array();

            foreach ( $attachments as $symbol => $attachment ) {
                $file_array = array(
                    'name' => $attachment['file_name'],
                );
                $file_path = $attachment['file_path'];
                $attachment_id = null;
                $attached_file = null;
                if ( isset( $existing_starter_content_posts[ 'attachment:' . $attachment['post_name'] ] ) ) {
                    $attachment_post = $existing_starter_content_posts[ 'attachment:' . $attachment['post_name'] ];
                    $attachment_id = $attachment_post->ID;
                    $attached_file = get_attached_file( $attachment_id );
                    if ( empty( $attached_file ) || ! file_exists( $attached_file ) ) {
                        $attachment_id = null;
                        $attached_file = null;
                    } elseif ( $this->get_stylesheet() !== get_post_meta( $attachment_post->ID, '_starter_content_theme', true ) ) {

                        // Re-generate attachment metadata since it was previously generated for a different theme.
                        $metadata = wp_generate_attachment_metadata( $attachment_post->ID, $attached_file );
                        wp_update_attachment_metadata( $attachment_id, $metadata );
                        update_post_meta( $attachment_id, '_starter_content_theme', $this->get_stylesheet() );
                    }
                }

                // Insert the attachment auto-draft because it doesn't yet exist or the attached file is gone.
                if ( ! $attachment_id ) {

                    // Copy file to temp location so that original file won't get deleted from theme after sideloading.
                    $temp_file_name = wp_tempnam( basename( $file_path ) );
                    if ( $temp_file_name && copy( $file_path, $temp_file_name ) ) {
                        $file_array['tmp_name'] = $temp_file_name;
                    }
                    if ( empty( $file_array['tmp_name'] ) ) {
                        continue;
                    }

                    $attachment_post_data = array_merge(
                        wp_array_slice_assoc( $attachment, array( 'post_title', 'post_content', 'post_excerpt' ) ),
                        array(
                            'post_status' => 'auto-draft', // So attachment will be garbage collected in a week if changeset is never published.
                        )
                    );

                    // In PHP < 5.6 filesize() returns 0 for the temp files unless we clear the file status cache.
                    // Technically, PHP < 5.6.0 || < 5.5.13 || < 5.4.29 but no need to be so targeted.
                    // See https://bugs.php.net/bug.php?id=65701
                    if ( version_compare( PHP_VERSION, '5.6', '<' ) ) {
                        clearstatcache();
                    }

                    $attachment_id = media_handle_sideload( $file_array, 0, null, $attachment_post_data );
                    if ( is_wp_error( $attachment_id ) ) {
                        continue;
                    }
                    update_post_meta( $attachment_id, '_starter_content_theme', $this->get_stylesheet() );
                    update_post_meta( $attachment_id, '_customize_draft_post_name', $attachment['post_name'] );
                }

                $attachment_ids[ $symbol ] = $attachment_id;
            }
            $starter_content_auto_draft_post_ids = array_merge( $starter_content_auto_draft_post_ids, array_values( $attachment_ids ) );
        }

        // Posts & pages.
        if ( ! empty( $posts ) ) {
            foreach ( array_keys( $posts ) as $post_symbol ) {
                if ( empty( $posts[ $post_symbol ]['post_type'] ) || empty( $posts[ $post_symbol ]['post_name'] ) ) {
                    continue;
                }
                $post_type = $posts[ $post_symbol ]['post_type'];
                if ( ! empty( $posts[ $post_symbol ]['post_name'] ) ) {
                    $post_name = $posts[ $post_symbol ]['post_name'];
                } elseif ( ! empty( $posts[ $post_symbol ]['post_title'] ) ) {
                    $post_name = sanitize_title( $posts[ $post_symbol ]['post_title'] );
                } else {
                    continue;
                }

                // Use existing auto-draft post if one already exists with the same type and name.
                if ( isset( $existing_starter_content_posts[ $post_type . ':' . $post_name ] ) ) {
                    $posts[ $post_symbol ]['ID'] = $existing_starter_content_posts[ $post_type . ':' . $post_name ]->ID;
                    continue;
                }

                // Translate the featured image symbol.
                if ( ! empty( $posts[ $post_symbol ]['thumbnail'] )
                    && preg_match( '/^{{(?P<symbol>.+)}}$/', $posts[ $post_symbol ]['thumbnail'], $matches )
                    && isset( $attachment_ids[ $matches['symbol'] ] ) ) {
                    $posts[ $post_symbol ]['meta_input']['_thumbnail_id'] = $attachment_ids[ $matches['symbol'] ];
                }

                if ( ! empty( $posts[ $post_symbol ]['template'] ) ) {
                    $posts[ $post_symbol ]['meta_input']['_wp_page_template'] = $posts[ $post_symbol ]['template'];
                }

                $r = $this->nav_menus->insert_auto_draft_post( $posts[ $post_symbol ] );
                if ( $r instanceof WP_Post ) {
                    $posts[ $post_symbol ]['ID'] = $r->ID;
                }
            }

            $starter_content_auto_draft_post_ids = array_merge( $starter_content_auto_draft_post_ids, wp_list_pluck( $posts, 'ID' ) );
        }

        // The nav_menus_created_posts setting is why nav_menus component is dependency for adding posts.
        if ( ! empty( $this->nav_menus ) && ! empty( $starter_content_auto_draft_post_ids ) ) {
            $setting_id = 'nav_menus_created_posts';
            $this->set_post_value( $setting_id, array_unique( array_values( $starter_content_auto_draft_post_ids ) ) );
            $this->pending_starter_content_settings_ids[] = $setting_id;
        }

        // Nav menus.
        $placeholder_id = -1;
        $reused_nav_menu_setting_ids = array();
        foreach ( $nav_menus as $nav_menu_location => $nav_menu ) {

            $nav_menu_term_id = null;
            $nav_menu_setting_id = null;
            $matches = array();

            // Look for an existing placeholder menu with starter content to re-use.
            foreach ( $changeset_data as $setting_id => $setting_params ) {
                $can_reuse = (
                    ! empty( $setting_params['starter_content'] )
                    &&
                    ! in_array( $setting_id, $reused_nav_menu_setting_ids, true )
                    &&
                    preg_match( '#^nav_menu\[(?P<nav_menu_id>-?\d+)\]$#', $setting_id, $matches )
                );
                if ( $can_reuse ) {
                    $nav_menu_term_id = intval( $matches['nav_menu_id'] );
                    $nav_menu_setting_id = $setting_id;
                    $reused_nav_menu_setting_ids[] = $setting_id;
                    break;
                }
            }

            if ( ! $nav_menu_term_id ) {
                while ( isset( $changeset_data[ sprintf( 'nav_menu[%d]', $placeholder_id ) ] ) ) {
                    $placeholder_id--;
                }
                $nav_menu_term_id = $placeholder_id;
                $nav_menu_setting_id = sprintf( 'nav_menu[%d]', $placeholder_id );
            }

            $this->set_post_value( $nav_menu_setting_id, array(
                'name' => isset( $nav_menu['name'] ) ? $nav_menu['name'] : $nav_menu_location,
            ) );
            $this->pending_starter_content_settings_ids[] = $nav_menu_setting_id;

            // @todo Add support for menu_item_parent.
            $position = 0;
            foreach ( $nav_menu['items'] as $nav_menu_item ) {
                $nav_menu_item_setting_id = sprintf( 'nav_menu_item[%d]', $placeholder_id-- );
                if ( ! isset( $nav_menu_item['position'] ) ) {
                    $nav_menu_item['position'] = $position++;
                }
                $nav_menu_item['nav_menu_term_id'] = $nav_menu_term_id;

                if ( isset( $nav_menu_item['object_id'] ) ) {
                    if ( 'post_type' === $nav_menu_item['type'] && preg_match( '/^{{(?P<symbol>.+)}}$/', $nav_menu_item['object_id'], $matches ) && isset( $posts[ $matches['symbol'] ] ) ) {
                        $nav_menu_item['object_id'] = $posts[ $matches['symbol'] ]['ID'];
                        if ( empty( $nav_menu_item['title'] ) ) {
                            $original_object = get_post( $nav_menu_item['object_id'] );
                            $nav_menu_item['title'] = $original_object->post_title;
                        }
                    } else {
                        continue;
                    }
                } else {
                    $nav_menu_item['object_id'] = 0;
                }

                if ( empty( $changeset_data[ $nav_menu_item_setting_id ] ) || ! empty( $changeset_data[ $nav_menu_item_setting_id ]['starter_content'] ) ) {
                    $this->set_post_value( $nav_menu_item_setting_id, $nav_menu_item );
                    $this->pending_starter_content_settings_ids[] = $nav_menu_item_setting_id;
                }
            }

            $setting_id = sprintf( 'nav_menu_locations[%s]', $nav_menu_location );
            if ( empty( $changeset_data[ $setting_id ] ) || ! empty( $changeset_data[ $setting_id ]['starter_content'] ) ) {
                $this->set_post_value( $setting_id, $nav_menu_term_id );
                $this->pending_starter_content_settings_ids[] = $setting_id;
            }
        }

        // Options.
        foreach ( $options as $name => $value ) {
            if ( preg_match( '/^{{(?P<symbol>.+)}}$/', $value, $matches ) ) {
                if ( isset( $posts[ $matches['symbol'] ] ) ) {
                    $value = $posts[ $matches['symbol'] ]['ID'];
                } elseif ( isset( $attachment_ids[ $matches['symbol'] ] ) ) {
                    $value = $attachment_ids[ $matches['symbol'] ];
                } else {
                    continue;
                }
            }

            if ( empty( $changeset_data[ $name ] ) || ! empty( $changeset_data[ $name ]['starter_content'] ) ) {
                $this->set_post_value( $name, $value );
                $this->pending_starter_content_settings_ids[] = $name;
            }
        }

        // Theme mods.
        foreach ( $theme_mods as $name => $value ) {
            if ( preg_match( '/^{{(?P<symbol>.+)}}$/', $value, $matches ) ) {
                if ( isset( $posts[ $matches['symbol'] ] ) ) {
                    $value = $posts[ $matches['symbol'] ]['ID'];
                } elseif ( isset( $attachment_ids[ $matches['symbol'] ] ) ) {
                    $value = $attachment_ids[ $matches['symbol'] ];
                } else {
                    continue;
                }
            }

            // Handle header image as special case since setting has a legacy format.
            if ( 'header_image' === $name ) {
                $name = 'header_image_data';
                $metadata = wp_get_attachment_metadata( $value );
                if ( empty( $metadata ) ) {
                    continue;
                }
                $value = array(
                    'attachment_id' => $value,
                    'url' => wp_get_attachment_url( $value ),
                    'height' => $metadata['height'],
                    'width' => $metadata['width'],
                );
            } elseif ( 'background_image' === $name ) {
                $value = wp_get_attachment_url( $value );
            }

            if ( empty( $changeset_data[ $name ] ) || ! empty( $changeset_data[ $name ]['starter_content'] ) ) {
                $this->set_post_value( $name, $value );
                $this->pending_starter_content_settings_ids[] = $name;
            }
        }

        if ( ! empty( $this->pending_starter_content_settings_ids ) ) {
            if ( did_action( 'customize_register' ) ) {
                $this->_save_starter_content_changeset();
            } else {
                add_action( 'customize_register', array( $this, '_save_starter_content_changeset' ), 1000 );
            }
        }
    }

    /**
     * Prepare starter content attachments.
     *
     * Ensure that the attachments are valid and that they have slugs and file name/path.
     *
     * @since 4.7.0
     *
     * @param array $attachments Attachments.
     * @return array Prepared attachments.
     */
    protected function prepare_starter_content_attachments( $attachments ) {
        $prepared_attachments = array();
        if ( empty( $attachments ) ) {
            return $prepared_attachments;
        }

        // Such is The WordPress Way.
        require_once( ABSPATH . 'wp-admin/includes/file.php' );
        require_once( ABSPATH . 'wp-admin/includes/media.php' );
        require_once( ABSPATH . 'wp-admin/includes/image.php' );

        foreach ( $attachments as $symbol => $attachment ) {

            // A file is required and URLs to files are not currently allowed.
            if ( empty( $attachment['file'] ) || preg_match( '#^https?://$#', $attachment['file'] ) ) {
                continue;
            }

            $file_path = null;
            if ( file_exists( $attachment['file'] ) ) {
                $file_path = $attachment['file']; // Could be absolute path to file in plugin.
            } elseif ( is_child_theme() && file_exists( get_stylesheet_directory() . '/' . $attachment['file'] ) ) {
                $file_path = get_stylesheet_directory() . '/' . $attachment['file'];
            } elseif ( file_exists( get_template_directory() . '/' . $attachment['file'] ) ) {
                $file_path = get_template_directory() . '/' . $attachment['file'];
            } else {
                continue;
            }
            $file_name = basename( $attachment['file'] );

            // Skip file types that are not recognized.
            $checked_filetype = wp_check_filetype( $file_name );
            if ( empty( $checked_filetype['type'] ) ) {
                continue;
            }

            // Ensure post_name is set since not automatically derived from post_title for new auto-draft posts.
            if ( empty( $attachment['post_name'] ) ) {
                if ( ! empty( $attachment['post_title'] ) ) {
                    $attachment['post_name'] = sanitize_title( $attachment['post_title'] );
                } else {
                    $attachment['post_name'] = sanitize_title( preg_replace( '/\.\w+$/', '', $file_name ) );
                }
            }

            $attachment['file_name'] = $file_name;
            $attachment['file_path'] = $file_path;
            $prepared_attachments[ $symbol ] = $attachment;
        }
        return $prepared_attachments;
    }

    /**
     * Save starter content changeset.
     *
     * @since 4.7.0
     */
    public function _save_starter_content_changeset() {

        if ( empty( $this->pending_starter_content_settings_ids ) ) {
            return;
        }

        $this->save_changeset_post( array(
            'data' => array_fill_keys( $this->pending_starter_content_settings_ids, array( 'starter_content' => true ) ),
            'starter_content' => true,
        ) );
        $this->saved_starter_content_changeset = true;

        $this->pending_starter_content_settings_ids = array();
    }

    /**
     * Get dirty pre-sanitized setting values in the current customized state.
     *
     * The returned array consists of a merge of three sources:
     * 1. If the theme is not currently active, then the base array is any stashed
     *    theme mods that were modified previously but never published.
     * 2. The values from the current changeset, if it exists.
     * 3. If the user can customize, the values parsed from the incoming
     *    `$_POST['customized']` JSON data.
     * 4. Any programmatically-set post values via `WP_Customize_Manager::set_post_value()`.
     *
     * The name "unsanitized_post_values" is a carry-over from when the customized
     * state was exclusively sourced from `$_POST['customized']`. Nevertheless,
     * the value returned will come from the current changeset post and from the
     * incoming post data.
     *
     * @since 4.1.1
     * @since 4.7.0 Added $args param and merging with changeset values and stashed theme mods.
     *
     * @param array $args {
     *     Args.
     *
     *     @type bool $exclude_changeset Whether the changeset values should also be excluded. Defaults to false.
     *     @type bool $exclude_post_data Whether the post input values should also be excluded. Defaults to false when lacking the customize capability.
     * }
     * @return array
     */
    public function unsanitized_post_values( $args = array() ) {
        $args = array_merge(
            array(
                'exclude_changeset' => false,
                'exclude_post_data' => ! current_user_can( 'customize' ),
            ),
            $args
        );

        $values = array();

        // Let default values be from the stashed theme mods if doing a theme switch and if no changeset is present.
        if ( ! $this->is_theme_active() ) {
            $stashed_theme_mods = get_option( 'customize_stashed_theme_mods' );
            $stylesheet = $this->get_stylesheet();
            if ( isset( $stashed_theme_mods[ $stylesheet ] ) ) {
                $values = array_merge( $values, wp_list_pluck( $stashed_theme_mods[ $stylesheet ], 'value' ) );
            }
        }

        if ( ! $args['exclude_changeset'] ) {
            foreach ( $this->changeset_data() as $setting_id => $setting_params ) {
                if ( ! array_key_exists( 'value', $setting_params ) ) {
                    continue;
                }
                if ( isset( $setting_params['type'] ) && 'theme_mod' === $setting_params['type'] ) {

                    // Ensure that theme mods values are only used if they were saved under the current theme.
                    $namespace_pattern = '/^(?P<stylesheet>.+?)::(?P<setting_id>.+)$/';
                    if ( preg_match( $namespace_pattern, $setting_id, $matches ) && $this->get_stylesheet() === $matches['stylesheet'] ) {
                        $values[ $matches['setting_id'] ] = $setting_params['value'];
                    }
                } else {
                    $values[ $setting_id ] = $setting_params['value'];
                }
            }
        }

        if ( ! $args['exclude_post_data'] ) {
            if ( ! isset( $this->_post_values ) ) {
                if ( isset( $_POST['customized'] ) ) {
                    $post_values = json_decode( wp_unslash( $_POST['customized'] ), true );
                } else {
                    $post_values = array();
                }
                if ( is_array( $post_values ) ) {
                    $this->_post_values = $post_values;
                } else {
                    $this->_post_values = array();
                }
            }
            $values = array_merge( $values, $this->_post_values );
        }
        return $values;
    }

    /**
     * Returns the sanitized value for a given setting from the current customized state.
     *
     * The name "post_value" is a carry-over from when the customized state was exclusively
     * sourced from `$_POST['customized']`. Nevertheless, the value returned will come
     * from the current changeset post and from the incoming post data.
     *
     * @since 3.4.0
     * @since 4.1.1 Introduced the `$default` parameter.
     * @since 4.6.0 `$default` is now returned early when the setting post value is invalid.
     *
     * @see WP_REST_Server::dispatch()
     * @see WP_REST_Request::sanitize_params()
     * @see WP_REST_Request::has_valid_params()
     *
     * @param WP_Customize_Setting $setting A WP_Customize_Setting derived object.
     * @param mixed                $default Value returned $setting has no post value (added in 4.2.0)
     *                                      or the post value is invalid (added in 4.6.0).
     * @return string|mixed $post_value Sanitized value or the $default provided.
     */
    public function post_value( $setting, $default = null ) {
        $post_values = $this->unsanitized_post_values();
        if ( ! array_key_exists( $setting->id, $post_values ) ) {
            return $default;
        }
        $value = $post_values[ $setting->id ];
        $valid = $setting->validate( $value );
        if ( is_wp_error( $valid ) ) {
            return $default;
        }
        $value = $setting->sanitize( $value );
        if ( is_null( $value ) || is_wp_error( $value ) ) {
            return $default;
        }
        return $value;
    }

    /**
     * Override a setting's value in the current customized state.
     *
     * The name "post_value" is a carry-over from when the customized state was
     * exclusively sourced from `$_POST['customized']`.
     *
     * @since 4.2.0
     *
     * @param string $setting_id ID for the WP_Customize_Setting instance.
     * @param mixed  $value      Post value.
     */
    public function set_post_value( $setting_id, $value ) {
        $this->unsanitized_post_values(); // Populate _post_values from $_POST['customized'].
        $this->_post_values[ $setting_id ] = $value;

        /**
         * Announce when a specific setting's unsanitized post value has been set.
         *
         * Fires when the WP_Customize_Manager::set_post_value() method is called.
         *
         * The dynamic portion of the hook name, `$setting_id`, refers to the setting ID.
         *
         * @since 4.4.0
         *
         * @param mixed                $value Unsanitized setting post value.
         * @param WP_Customize_Manager $this  WP_Customize_Manager instance.
         */
        do_action( "customize_post_value_set_{$setting_id}", $value, $this );

        /**
         * Announce when any setting's unsanitized post value has been set.
         *
         * Fires when the WP_Customize_Manager::set_post_value() method is called.
         *
         * This is useful for `WP_Customize_Setting` instances to watch
         * in order to update a cached previewed value.
         *
         * @since 4.4.0
         *
         * @param string               $setting_id Setting ID.
         * @param mixed                $value      Unsanitized setting post value.
         * @param WP_Customize_Manager $this       WP_Customize_Manager instance.
         */
        do_action( 'customize_post_value_set', $setting_id, $value, $this );
    }

    /**
     * Print JavaScript settings.
     *
     * @since 3.4.0
     */
    public function customize_preview_init() {

        /*
         * Now that Customizer previews are loaded into iframes via GET requests
         * and natural URLs with transaction UUIDs added, we need to ensure that
         * the responses are never cached by proxies. In practice, this will not
         * be needed if the user is logged-in anyway. But if anonymous access is
         * allowed then the auth cookies would not be sent and WordPress would
         * not send no-cache headers by default.
         */
        if ( ! headers_sent() ) {
            nocache_headers();
            header( 'X-Robots: noindex, nofollow, noarchive' );
        }
        add_action( 'wp_head', 'wp_no_robots' );
        add_filter( 'wp_headers', array( $this, 'filter_iframe_security_headers' ) );

        /*
         * If preview is being served inside the customizer preview iframe, and
         * if the user doesn't have customize capability, then it is assumed
         * that the user's session has expired and they need to re-authenticate.
         */
        if ( $this->messenger_channel && ! current_user_can( 'customize' ) ) {
            $this->wp_die( -1, __( 'Unauthorized. You may remove the customize_messenger_channel param to preview as frontend.' ) );
            return;
        }

        $this->prepare_controls();

        add_filter( 'wp_redirect', array( $this, 'add_state_query_params' ) );

        wp_enqueue_script( 'customize-preview' );
        wp_enqueue_style( 'customize-preview' );
        add_action( 'wp_head', array( $this, 'customize_preview_loading_style' ) );
        add_action( 'wp_head', array( $this, 'remove_frameless_preview_messenger_channel' ) );
        add_action( 'wp_footer', array( $this, 'customize_preview_settings' ), 20 );
        add_filter( 'get_edit_post_link', '__return_empty_string' );

        /**
         * Fires once the Customizer preview has initialized and JavaScript
         * settings have been printed.
         *
         * @since 3.4.0
         *
         * @param WP_Customize_Manager $this WP_Customize_Manager instance.
         */
        do_action( 'customize_preview_init', $this );
    }

    /**
     * Filter the X-Frame-Options and Content-Security-Policy headers to ensure frontend can load in customizer.
     *
     * @since 4.7.0
     *
     * @param array $headers Headers.
     * @return array Headers.
     */
    public function filter_iframe_security_headers( $headers ) {
        $customize_url = admin_url( 'customize.php' );
        $headers['X-Frame-Options'] = 'ALLOW-FROM ' . $customize_url;
        $headers['Content-Security-Policy'] = 'frame-ancestors ' . preg_replace( '#^(\w+://[^/]+).+?$#', '$1', $customize_url );
        return $headers;
    }

    /**
     * Add customize state query params to a given URL if preview is allowed.
     *
     * @since 4.7.0
     * @see wp_redirect()
     * @see WP_Customize_Manager::get_allowed_url()
     *
     * @param string $url URL.
     * @return string URL.
     */
    public function add_state_query_params( $url ) {
        $parsed_original_url = wp_parse_url( $url );
        $is_allowed = false;
        foreach ( $this->get_allowed_urls() as $allowed_url ) {
            $parsed_allowed_url = wp_parse_url( $allowed_url );
            $is_allowed = (
                $parsed_allowed_url['scheme'] === $parsed_original_url['scheme']
                &&
                $parsed_allowed_url['host'] === $parsed_original_url['host']
                &&
                0 === strpos( $parsed_original_url['path'], $parsed_allowed_url['path'] )
            );
            if ( $is_allowed ) {
                break;
            }
        }

        if ( $is_allowed ) {
            $query_params = array(
                'customize_changeset_uuid' => $this->changeset_uuid(),
            );
            if ( ! $this->is_theme_active() ) {
                $query_params['customize_theme'] = $this->get_stylesheet();
            }
            if ( $this->messenger_channel ) {
                $query_params['customize_messenger_channel'] = $this->messenger_channel;
            }
            $url = add_query_arg( $query_params, $url );
        }

        return $url;
    }

    /**
     * Prevent sending a 404 status when returning the response for the customize
     * preview, since it causes the jQuery Ajax to fail. Send 200 instead.
     *
     * @since 4.0.0
     * @deprecated 4.7.0
     */
    public function customize_preview_override_404_status() {
        _deprecated_function( __METHOD__, '4.7.0' );
    }

    /**
     * Print base element for preview frame.
     *
     * @since 3.4.0
     * @deprecated 4.7.0
     */
    public function customize_preview_base() {
        _deprecated_function( __METHOD__, '4.7.0' );
    }

    /**
     * Print a workaround to handle HTML5 tags in IE < 9.
     *
     * @since 3.4.0
     * @deprecated 4.7.0 Customizer no longer supports IE8, so all supported browsers recognize HTML5.
     */
    public function customize_preview_html5() {
        _deprecated_function( __FUNCTION__, '4.7.0' );
    }

    /**
     * Print CSS for loading indicators for the Customizer preview.
     *
     * @since 4.2.0
     */
    public function customize_preview_loading_style() {
        ?><style>
            body.wp-customizer-unloading {
                opacity: 0.25;
                cursor: progress !important;
                -webkit-transition: opacity 0.5s;
                transition: opacity 0.5s;
            }
            body.wp-customizer-unloading * {
                pointer-events: none !important;
            }
            form.customize-unpreviewable,
            form.customize-unpreviewable input,
            form.customize-unpreviewable select,
            form.customize-unpreviewable button,
            a.customize-unpreviewable,
            area.customize-unpreviewable {
                cursor: not-allowed !important;
            }
        </style><?php
    }

    /**
     * Remove customize_messenger_channel query parameter from the preview window when it is not in an iframe.
     *
     * This ensures that the admin bar will be shown. It also ensures that link navigation will
     * work as expected since the parent frame is not being sent the URL to navigate to.
     *
     * @since 4.7.0
     */
    public function remove_frameless_preview_messenger_channel() {
        if ( ! $this->messenger_channel ) {
            return;
        }
        ?>
        <script>
        ( function() {
            var urlParser, oldQueryParams, newQueryParams, i;
            if ( parent !== window ) {
                return;
            }
            urlParser = document.createElement( 'a' );
            urlParser.href = location.href;
            oldQueryParams = urlParser.search.substr( 1 ).split( /&/ );
            newQueryParams = [];
            for ( i = 0; i < oldQueryParams.length; i += 1 ) {
                if ( ! /^customize_messenger_channel=/.test( oldQueryParams[ i ] ) ) {
                    newQueryParams.push( oldQueryParams[ i ] );
                }
            }
            urlParser.search = newQueryParams.join( '&' );
            if ( urlParser.search !== location.search ) {
                location.replace( urlParser.href );
            }
        } )();
        </script>
        <?php
    }

    /**
     * Print JavaScript settings for preview frame.
     *
     * @since 3.4.0
     */
    public function customize_preview_settings() {
        $post_values = $this->unsanitized_post_values( array( 'exclude_changeset' => true ) );
        $setting_validities = $this->validate_setting_values( $post_values );
        $exported_setting_validities = array_map( array( $this, 'prepare_setting_validity_for_js' ), $setting_validities );

        // Note that the REQUEST_URI is not passed into home_url() since this breaks subdirectory installations.
        $self_url = empty( $_SERVER['REQUEST_URI'] ) ? home_url( '/' ) : esc_url_raw( wp_unslash( $_SERVER['REQUEST_URI'] ) );
        $state_query_params = array(
            'customize_theme',
            'customize_changeset_uuid',
            'customize_messenger_channel',
        );
        $self_url = remove_query_arg( $state_query_params, $self_url );

        $allowed_urls = $this->get_allowed_urls();
        $allowed_hosts = array();
        foreach ( $allowed_urls as $allowed_url ) {
            $parsed = wp_parse_url( $allowed_url );
            if ( empty( $parsed['host'] ) ) {
                continue;
            }
            $host = $parsed['host'];
            if ( ! empty( $parsed['port'] ) ) {
                $host .= ':' . $parsed['port'];
            }
            $allowed_hosts[] = $host;
        }

        $switched_locale = switch_to_locale( get_user_locale() );
        $l10n = array(
            'shiftClickToEdit' => __( 'Shift-click to edit this element.' ),
            'linkUnpreviewable' => __( 'This link is not live-previewable.' ),
            'formUnpreviewable' => __( 'This form is not live-previewable.' ),
        );
        if ( $switched_locale ) {
            restore_previous_locale();
        }

        $settings = array(
            'changeset' => array(
                'uuid' => $this->changeset_uuid(),
                'autosaved' => $this->autosaved(),
            ),
            'timeouts' => array(
                'selectiveRefresh' => 250,
                'keepAliveSend' => 1000,
            ),
            'theme' => array(
                'stylesheet' => $this->get_stylesheet(),
                'active'     => $this->is_theme_active(),
            ),
            'url' => array(
                'self' => $self_url,
                'allowed' => array_map( 'esc_url_raw', $this->get_allowed_urls() ),
                'allowedHosts' => array_unique( $allowed_hosts ),
                'isCrossDomain' => $this->is_cross_domain(),
            ),
            'channel' => $this->messenger_channel,
            'activePanels' => array(),
            'activeSections' => array(),
            'activeControls' => array(),
            'settingValidities' => $exported_setting_validities,
            'nonce' => current_user_can( 'customize' ) ? $this->get_nonces() : array(),
            'l10n' => $l10n,
            '_dirty' => array_keys( $post_values ),
        );

        foreach ( $this->panels as $panel_id => $panel ) {
            if ( $panel->check_capabilities() ) {
                $settings['activePanels'][ $panel_id ] = $panel->active();
                foreach ( $panel->sections as $section_id => $section ) {
                    if ( $section->check_capabilities() ) {
                        $settings['activeSections'][ $section_id ] = $section->active();
                    }
                }
            }
        }
        foreach ( $this->sections as $id => $section ) {
            if ( $section->check_capabilities() ) {
                $settings['activeSections'][ $id ] = $section->active();
            }
        }
        foreach ( $this->controls as $id => $control ) {
            if ( $control->check_capabilities() ) {
                $settings['activeControls'][ $id ] = $control->active();
            }
        }

        ?>
        <script type="text/javascript">
            var _wpCustomizeSettings = <?php echo wp_json_encode( $settings ); ?>;
            _wpCustomizeSettings.values = {};
            (function( v ) {
                <?php
                /*
                 * Serialize settings separately from the initial _wpCustomizeSettings
                 * serialization in order to avoid a peak memory usage spike.
                 * @todo We may not even need to export the values at all since the pane syncs them anyway.
                 */
                foreach ( $this->settings as $id => $setting ) {
                    if ( $setting->check_capabilities() ) {
                        printf(
                            "v[%s] = %s;\n",
                            wp_json_encode( $id ),
                            wp_json_encode( $setting->js_value() )
                        );
                    }
                }
                ?>
            })( _wpCustomizeSettings.values );
        </script>
        <?php
    }

    /**
     * Prints a signature so we can ensure the Customizer was properly executed.
     *
     * @since 3.4.0
     * @deprecated 4.7.0
     */
    public function customize_preview_signature() {
        _deprecated_function( __METHOD__, '4.7.0' );
    }

    /**
     * Removes the signature in case we experience a case where the Customizer was not properly executed.
     *
     * @since 3.4.0
     * @deprecated 4.7.0
     *
     * @param mixed $return Value passed through for {@see 'wp_die_handler'} filter.
     * @return mixed Value passed through for {@see 'wp_die_handler'} filter.
     */
    public function remove_preview_signature( $return = null ) {
        _deprecated_function( __METHOD__, '4.7.0' );

        return $return;
    }

    /**
     * Is it a theme preview?
     *
     * @since 3.4.0
     *
     * @return bool True if it's a preview, false if not.
     */
    public function is_preview() {
        return (bool) $this->previewing;
    }

    /**
     * Retrieve the template name of the previewed theme.
     *
     * @since 3.4.0
     *
     * @return string Template name.
     */
    public function get_template() {
        return $this->theme()->get_template();
    }

    /**
     * Retrieve the stylesheet name of the previewed theme.
     *
     * @since 3.4.0
     *
     * @return string Stylesheet name.
     */
    public function get_stylesheet() {
        return $this->theme()->get_stylesheet();
    }

    /**
     * Retrieve the template root of the previewed theme.
     *
     * @since 3.4.0
     *
     * @return string Theme root.
     */
    public function get_template_root() {
        return get_raw_theme_root( $this->get_template(), true );
    }

    /**
     * Retrieve the stylesheet root of the previewed theme.
     *
     * @since 3.4.0
     *
     * @return string Theme root.
     */
    public function get_stylesheet_root() {
        return get_raw_theme_root( $this->get_stylesheet(), true );
    }

    /**
     * Filters the current theme and return the name of the previewed theme.
     *
     * @since 3.4.0
     *
     * @param $current_theme {@internal Parameter is not used}
     * @return string Theme name.
     */
    public function current_theme( $current_theme ) {
        return $this->theme()->display('Name');
    }

    /**
     * Validates setting values.
     *
     * Validation is skipped for unregistered settings or for values that are
     * already null since they will be skipped anyway. Sanitization is applied
     * to values that pass validation, and values that become null or `WP_Error`
     * after sanitizing are marked invalid.
     *
     * @since 4.6.0
     *
     * @see WP_REST_Request::has_valid_params()
     * @see WP_Customize_Setting::validate()
     *
     * @param array $setting_values Mapping of setting IDs to values to validate and sanitize.
     * @param array $options {
     *     Options.
     *
     *     @type bool $validate_existence  Whether a setting's existence will be checked.
     *     @type bool $validate_capability Whether the setting capability will be checked.
     * }
     * @return array Mapping of setting IDs to return value of validate method calls, either `true` or `WP_Error`.
     */
    public function validate_setting_values( $setting_values, $options = array() ) {
        $options = wp_parse_args( $options, array(
            'validate_capability' => false,
            'validate_existence' => false,
        ) );

        $validities = array();
        foreach ( $setting_values as $setting_id => $unsanitized_value ) {
            $setting = $this->get_setting( $setting_id );
            if ( ! $setting ) {
                if ( $options['validate_existence'] ) {
                    $validities[ $setting_id ] = new WP_Error( 'unrecognized', __( 'Setting does not exist or is unrecognized.' ) );
                }
                continue;
            }
            if ( $options['validate_capability'] && ! current_user_can( $setting->capability ) ) {
                $validity = new WP_Error( 'unauthorized', __( 'Unauthorized to modify setting due to capability.' ) );
            } else {
                if ( is_null( $unsanitized_value ) ) {
                    continue;
                }
                $validity = $setting->validate( $unsanitized_value );
            }
            if ( ! is_wp_error( $validity ) ) {
                /** This filter is documented in wp-includes/class-wp-customize-setting.php */
                $late_validity = apply_filters( "customize_validate_{$setting->id}", new WP_Error(), $unsanitized_value, $setting );
                if ( ! empty( $late_validity->errors ) ) {
                    $validity = $late_validity;
                }
            }
            if ( ! is_wp_error( $validity ) ) {
                $value = $setting->sanitize( $unsanitized_value );
                if ( is_null( $value ) ) {
                    $validity = false;
                } elseif ( is_wp_error( $value ) ) {
                    $validity = $value;
                }
            }
            if ( false === $validity ) {
                $validity = new WP_Error( 'invalid_value', __( 'Invalid value.' ) );
            }
            $validities[ $setting_id ] = $validity;
        }
        return $validities;
    }

    /**
     * Prepares setting validity for exporting to the client (JS).
     *
     * Converts `WP_Error` instance into array suitable for passing into the
     * `wp.customize.Notification` JS model.
     *
     * @since 4.6.0
     *
     * @param true|WP_Error $validity Setting validity.
     * @return true|array If `$validity` was a WP_Error, the error codes will be array-mapped
     *                    to their respective `message` and `data` to pass into the
     *                    `wp.customize.Notification` JS model.
     */
    public function prepare_setting_validity_for_js( $validity ) {
        if ( is_wp_error( $validity ) ) {
            $notification = array();
            foreach ( $validity->errors as $error_code => $error_messages ) {
                $notification[ $error_code ] = array(
                    'message' => join( ' ', $error_messages ),
                    'data' => $validity->get_error_data( $error_code ),
                );
            }
            return $notification;
        } else {
            return true;
        }
    }

    /**
     * Handle customize_save WP Ajax request to save/update a changeset.
     *
     * @since 3.4.0
     * @since 4.7.0 The semantics of this method have changed to update a changeset, optionally to also change the status and other attributes.
     */
    public function save() {
        if ( ! is_user_logged_in() ) {
            wp_send_json_error( 'unauthenticated' );
        }

        if ( ! $this->is_preview() ) {
            wp_send_json_error( 'not_preview' );
        }

        $action = 'save-customize_' . $this->get_stylesheet();
        if ( ! check_ajax_referer( $action, 'nonce', false ) ) {
            wp_send_json_error( 'invalid_nonce' );
        }

        $changeset_post_id = $this->changeset_post_id();
        $is_new_changeset = empty( $changeset_post_id );
        if ( $is_new_changeset ) {
            if ( ! current_user_can( get_post_type_object( 'customize_changeset' )->cap->create_posts ) ) {
                wp_send_json_error( 'cannot_create_changeset_post' );
            }
        } else {
            if ( ! current_user_can( get_post_type_object( 'customize_changeset' )->cap->edit_post, $changeset_post_id ) ) {
                wp_send_json_error( 'cannot_edit_changeset_post' );
            }
        }

        if ( ! empty( $_POST['customize_changeset_data'] ) ) {
            $input_changeset_data = json_decode( wp_unslash( $_POST['customize_changeset_data'] ), true );
            if ( ! is_array( $input_changeset_data ) ) {
                wp_send_json_error( 'invalid_customize_changeset_data' );
            }
        } else {
            $input_changeset_data = array();
        }

        // Validate title.
        $changeset_title = null;
        if ( isset( $_POST['customize_changeset_title'] ) ) {
            $changeset_title = sanitize_text_field( wp_unslash( $_POST['customize_changeset_title'] ) );
        }

        // Validate changeset status param.
        $is_publish = null;
        $changeset_status = null;
        if ( isset( $_POST['customize_changeset_status'] ) ) {
            $changeset_status = wp_unslash( $_POST['customize_changeset_status'] );
            if ( ! get_post_status_object( $changeset_status ) || ! in_array( $changeset_status, array( 'draft', 'pending', 'publish', 'future' ), true ) ) {
                wp_send_json_error( 'bad_customize_changeset_status', 400 );
            }
            $is_publish = ( 'publish' === $changeset_status || 'future' === $changeset_status );
            if ( $is_publish && ! current_user_can( get_post_type_object( 'customize_changeset' )->cap->publish_posts ) ) {
                wp_send_json_error( 'changeset_publish_unauthorized', 403 );
            }
        }

        /*
         * Validate changeset date param. Date is assumed to be in local time for
         * the WP if in MySQL format (YYYY-MM-DD HH:MM:SS). Otherwise, the date
         * is parsed with strtotime() so that ISO date format may be supplied
         * or a string like "+10 minutes".
         */
        $changeset_date_gmt = null;
        if ( isset( $_POST['customize_changeset_date'] ) ) {
            $changeset_date = wp_unslash( $_POST['customize_changeset_date'] );
            if ( preg_match( '/^\d\d\d\d-\d\d-\d\d \d\d:\d\d:\d\d$/', $changeset_date ) ) {
                $mm = substr( $changeset_date, 5, 2 );
                $jj = substr( $changeset_date, 8, 2 );
                $aa = substr( $changeset_date, 0, 4 );
                $valid_date = wp_checkdate( $mm, $jj, $aa, $changeset_date );
                if ( ! $valid_date ) {
                    wp_send_json_error( 'bad_customize_changeset_date', 400 );
                }
                $changeset_date_gmt = get_gmt_from_date( $changeset_date );
            } else {
                $timestamp = strtotime( $changeset_date );
                if ( ! $timestamp ) {
                    wp_send_json_error( 'bad_customize_changeset_date', 400 );
                }
                $changeset_date_gmt = gmdate( 'Y-m-d H:i:s', $timestamp );
            }
        }

        $lock_user_id = null;
        $autosave = ! empty( $_POST['customize_changeset_autosave'] );
        if ( ! $is_new_changeset ) {
            $lock_user_id = wp_check_post_lock( $this->changeset_post_id() );
        }

        // Force request to autosave when changeset is locked.
        if ( $lock_user_id && ! $autosave ) {
            $autosave = true;
            $changeset_status = null;
            $changeset_date_gmt = null;
        }

        if ( $autosave && ! defined( 'DOING_AUTOSAVE' ) ) { // Back-compat.
            define( 'DOING_AUTOSAVE', true );
        }

        $autosaved = false;
        $r = $this->save_changeset_post( array(
            'status' => $changeset_status,
            'title' => $changeset_title,
            'date_gmt' => $changeset_date_gmt,
            'data' => $input_changeset_data,
            'autosave' => $autosave,
        ) );
        if ( $autosave && ! is_wp_error( $r ) ) {
            $autosaved = true;
        }

        // If the changeset was locked and an autosave request wasn't itself an error, then now explicitly return with a failure.
        if ( $lock_user_id && ! is_wp_error( $r ) ) {
            $r = new WP_Error(
                'changeset_locked',
                __( 'Changeset is being edited by other user.' ),
                array(
                    'lock_user' => $this->get_lock_user_data( $lock_user_id ),
                )
            );
        }

        if ( is_wp_error( $r ) ) {
            $response = array(
                'message' => $r->get_error_message(),
                'code' => $r->get_error_code(),
            );
            if ( is_array( $r->get_error_data() ) ) {
                $response = array_merge( $response, $r->get_error_data() );
            } else {
                $response['data'] = $r->get_error_data();
            }
        } else {
            $response = $r;
            $changeset_post = get_post( $this->changeset_post_id() );

            // Dismiss all other auto-draft changeset posts for this user (they serve like autosave revisions), as there should only be one.
            if ( $is_new_changeset ) {
                $this->dismiss_user_auto_draft_changesets();
            }

            // Note that if the changeset status was publish, then it will get set to trash if revisions are not supported.
            $response['changeset_status'] = $changeset_post->post_status;
            if ( $is_publish && 'trash' === $response['changeset_status'] ) {
                $response['changeset_status'] = 'publish';
            }

            if ( 'publish' !== $response['changeset_status'] ) {
                $this->set_changeset_lock( $changeset_post->ID );
            }

            if ( 'future' === $response['changeset_status'] ) {
                $response['changeset_date'] = $changeset_post->post_date;
            }

            if ( 'publish' === $response['changeset_status'] || 'trash' === $response['changeset_status'] ) {
                $response['next_changeset_uuid'] = wp_generate_uuid4();
            }
        }

        if ( $autosave ) {
            $response['autosaved'] = $autosaved;
        }

        if ( isset( $response['setting_validities'] ) ) {
            $response['setting_validities'] = array_map( array( $this, 'prepare_setting_validity_for_js' ), $response['setting_validities'] );
        }

        /**
         * Filters response data for a successful customize_save Ajax request.
         *
         * This filter does not apply if there was a nonce or authentication failure.
         *
         * @since 4.2.0
         *
         * @param array                $response Additional information passed back to the 'saved'
         *                                       event on `wp.customize`.
         * @param WP_Customize_Manager $this     WP_Customize_Manager instance.
         */
        $response = apply_filters( 'customize_save_response', $response, $this );

        if ( is_wp_error( $r ) ) {
            wp_send_json_error( $response );
        } else {
            wp_send_json_success( $response );
        }
    }

    /**
     * Save the post for the loaded changeset.
     *
     * @since 4.7.0
     *
     * @param array $args {
     *     Args for changeset post.
     *
     *     @type array  $data            Optional additional changeset data. Values will be merged on top of any existing post values.
     *     @type string $status          Post status. Optional. If supplied, the save will be transactional and a post revision will be allowed.
     *     @type string $title           Post title. Optional.
     *     @type string $date_gmt        Date in GMT. Optional.
     *     @type int    $user_id         ID for user who is saving the changeset. Optional, defaults to the current user ID.
     *     @type bool   $starter_content Whether the data is starter content. If false (default), then $starter_content will be cleared for any $data being saved.
     *     @type bool   $autosave        Whether this is a request to create an autosave revision.
     * }
     *
     * @return array|WP_Error Returns array on success and WP_Error with array data on error.
     */
    function save_changeset_post( $args = array() ) {

        $args = array_merge(
            array(
                'status' => null,
                'title' => null,
                'data' => array(),
                'date_gmt' => null,
                'user_id' => get_current_user_id(),
                'starter_content' => false,
                'autosave' => false,
            ),
            $args
        );

        $changeset_post_id = $this->changeset_post_id();
        $existing_changeset_data = array();
        if ( $changeset_post_id ) {
            $existing_status = get_post_status( $changeset_post_id );
            if ( 'publish' === $existing_status || 'trash' === $existing_status ) {
                return new WP_Error(
                    'changeset_already_published',
                    __( 'The previous set of changes has already been published. Please try saving your current set of changes again.' ),
                    array(
                        'next_changeset_uuid' => wp_generate_uuid4(),
                    )
                );
            }

            $existing_changeset_data = $this->get_changeset_post_data( $changeset_post_id );
            if ( is_wp_error( $existing_changeset_data ) ) {
                return $existing_changeset_data;
            }
        }

        // Fail if attempting to publish but publish hook is missing.
        if ( 'publish' === $args['status'] && false === has_action( 'transition_post_status', '_wp_customize_publish_changeset' ) ) {
            return new WP_Error( 'missing_publish_callback' );
        }

        // Validate date.
        $now = gmdate( 'Y-m-d H:i:59' );
        if ( $args['date_gmt'] ) {
            $is_future_dated = ( mysql2date( 'U', $args['date_gmt'], false ) > mysql2date( 'U', $now, false ) );
            if ( ! $is_future_dated ) {
                return new WP_Error( 'not_future_date', __( 'You must supply a future date to schedule.' ) ); // Only future dates are allowed.
            }

            if ( ! $this->is_theme_active() && ( 'future' === $args['status'] || $is_future_dated ) ) {
                return new WP_Error( 'cannot_schedule_theme_switches' ); // This should be allowed in the future, when theme is a regular setting.
            }
            $will_remain_auto_draft = ( ! $args['status'] && ( ! $changeset_post_id || 'auto-draft' === get_post_status( $changeset_post_id ) ) );
            if ( $will_remain_auto_draft ) {
                return new WP_Error( 'cannot_supply_date_for_auto_draft_changeset' );
            }
        } elseif ( $changeset_post_id && 'future' === $args['status'] ) {

            // Fail if the new status is future but the existing post's date is not in the future.
            $changeset_post = get_post( $changeset_post_id );
            if ( mysql2date( 'U', $changeset_post->post_date_gmt, false ) <= mysql2date( 'U', $now, false ) ) {
                return new WP_Error( 'not_future_date', __( 'You must supply a future date to schedule.' ) );
            }
        }

        if ( ! empty( $is_future_dated ) && 'publish' === $args['status'] ) {
            $args['status'] = 'future';
        }

        // Validate autosave param. See _wp_post_revision_fields() for why these fields are disallowed.
        if ( $args['autosave'] ) {
            if ( $args['date_gmt'] ) {
                return new WP_Error( 'illegal_autosave_with_date_gmt' );
            } elseif ( $args['status'] ) {
                return new WP_Error( 'illegal_autosave_with_status' );
            } elseif ( $args['user_id'] && get_current_user_id() !== $args['user_id'] ) {
                return new WP_Error( 'illegal_autosave_with_non_current_user' );
            }
        }

        // The request was made via wp.customize.previewer.save().
        $update_transactionally = (bool) $args['status'];
        $allow_revision = (bool) $args['status'];

        // Amend post values with any supplied data.
        foreach ( $args['data'] as $setting_id => $setting_params ) {
            if ( is_array( $setting_params ) && array_key_exists( 'value', $setting_params ) ) {
                $this->set_post_value( $setting_id, $setting_params['value'] ); // Add to post values so that they can be validated and sanitized.
            }
        }

        // Note that in addition to post data, this will include any stashed theme mods.
        $post_values = $this->unsanitized_post_values( array(
            'exclude_changeset' => true,
            'exclude_post_data' => false,
        ) );
        $this->add_dynamic_settings( array_keys( $post_values ) ); // Ensure settings get created even if they lack an input value.

        /*
         * Get list of IDs for settings that have values different from what is currently
         * saved in the changeset. By skipping any values that are already the same, the
         * subset of changed settings can be passed into validate_setting_values to prevent
         * an underprivileged modifying a single setting for which they have the capability
         * from being blocked from saving. This also prevents a user from touching of the
         * previous saved settings and overriding the associated user_id if they made no change.
         */
        $changed_setting_ids = array();
        foreach ( $post_values as $setting_id => $setting_value ) {
            $setting = $this->get_setting( $setting_id );

            if ( $setting && 'theme_mod' === $setting->type ) {
                $prefixed_setting_id = $this->get_stylesheet() . '::' . $setting->id;
            } else {
                $prefixed_setting_id = $setting_id;
            }

            $is_value_changed = (
                ! isset( $existing_changeset_data[ $prefixed_setting_id ] )
                ||
                ! array_key_exists( 'value', $existing_changeset_data[ $prefixed_setting_id ] )
                ||
                $existing_changeset_data[ $prefixed_setting_id ]['value'] !== $setting_value
            );
            if ( $is_value_changed ) {
                $changed_setting_ids[] = $setting_id;
            }
        }

        /**
         * Fires before save validation happens.
         *
         * Plugins can add just-in-time {@see 'customize_validate_{$this->ID}'} filters
         * at this point to catch any settings registered after `customize_register`.
         * The dynamic portion of the hook name, `$this->ID` refers to the setting ID.
         *
         * @since 4.6.0
         *
         * @param WP_Customize_Manager $this WP_Customize_Manager instance.
         */
        do_action( 'customize_save_validation_before', $this );

        // Validate settings.
        $validated_values = array_merge(
            array_fill_keys( array_keys( $args['data'] ), null ), // Make sure existence/capability checks are done on value-less setting updates.
            $post_values
        );
        $setting_validities = $this->validate_setting_values( $validated_values, array(
            'validate_capability' => true,
            'validate_existence' => true,
        ) );
        $invalid_setting_count = count( array_filter( $setting_validities, 'is_wp_error' ) );

        /*
         * Short-circuit if there are invalid settings the update is transactional.
         * A changeset update is transactional when a status is supplied in the request.
         */
        if ( $update_transactionally && $invalid_setting_count > 0 ) {
            $response = array(
                'setting_validities' => $setting_validities,
                /* translators: %s: number of invalid settings */
                'message' => sprintf( _n( 'Unable to save due to %s invalid setting.', 'Unable to save due to %s invalid settings.', $invalid_setting_count ), number_format_i18n( $invalid_setting_count ) ),
            );
            return new WP_Error( 'transaction_fail', '', $response );
        }

        // Obtain/merge data for changeset.
        $original_changeset_data = $this->get_changeset_post_data( $changeset_post_id );
        $data = $original_changeset_data;
        if ( is_wp_error( $data ) ) {
            $data = array();
        }

        // Ensure that all post values are included in the changeset data.
        foreach ( $post_values as $setting_id => $post_value ) {
            if ( ! isset( $args['data'][ $setting_id ] ) ) {
                $args['data'][ $setting_id ] = array();
            }
            if ( ! isset( $args['data'][ $setting_id ]['value'] ) ) {
                $args['data'][ $setting_id ]['value'] = $post_value;
            }
        }

        foreach ( $args['data'] as $setting_id => $setting_params ) {
            $setting = $this->get_setting( $setting_id );
            if ( ! $setting || ! $setting->check_capabilities() ) {
                continue;
            }

            // Skip updating changeset for invalid setting values.
            if ( isset( $setting_validities[ $setting_id ] ) && is_wp_error( $setting_validities[ $setting_id ] ) ) {
                continue;
            }

            $changeset_setting_id = $setting_id;
            if ( 'theme_mod' === $setting->type ) {
                $changeset_setting_id = sprintf( '%s::%s', $this->get_stylesheet(), $setting_id );
            }

            if ( null === $setting_params ) {
                // Remove setting from changeset entirely.
                unset( $data[ $changeset_setting_id ] );
            } else {

                if ( ! isset( $data[ $changeset_setting_id ] ) ) {
                    $data[ $changeset_setting_id ] = array();
                }

                // Merge any additional setting params that have been supplied with the existing params.
                $merged_setting_params = array_merge( $data[ $changeset_setting_id ], $setting_params );

                // Skip updating setting params if unchanged (ensuring the user_id is not overwritten).
                if ( $data[ $changeset_setting_id ] === $merged_setting_params ) {
                    continue;
                }

                $data[ $changeset_setting_id ] = array_merge(
                    $merged_setting_params,
                    array(
                        'type' => $setting->type,
                        'user_id' => $args['user_id'],
                        'date_modified_gmt' => current_time( 'mysql', true ),
                    )
                );

                // Clear starter_content flag in data if changeset is not explicitly being updated for starter content.
                if ( empty( $args['starter_content'] ) ) {
                    unset( $data[ $changeset_setting_id ]['starter_content'] );
                }
            }
        }

        $filter_context = array(
            'uuid' => $this->changeset_uuid(),
            'title' => $args['title'],
            'status' => $args['status'],
            'date_gmt' => $args['date_gmt'],
            'post_id' => $changeset_post_id,
            'previous_data' => is_wp_error( $original_changeset_data ) ? array() : $original_changeset_data,
            'manager' => $this,
        );

        /**
         * Filters the settings' data that will be persisted into the changeset.
         *
         * Plugins may amend additional data (such as additional meta for settings) into the changeset with this filter.
         *
         * @since 4.7.0
         *
         * @param array $data Updated changeset data, mapping setting IDs to arrays containing a $value item and optionally other metadata.
         * @param array $context {
         *     Filter context.
         *
         *     @type string               $uuid          Changeset UUID.
         *     @type string               $title         Requested title for the changeset post.
         *     @type string               $status        Requested status for the changeset post.
         *     @type string               $date_gmt      Requested date for the changeset post in MySQL format and GMT timezone.
         *     @type int|false            $post_id       Post ID for the changeset, or false if it doesn't exist yet.
         *     @type array                $previous_data Previous data contained in the changeset.
         *     @type WP_Customize_Manager $manager       Manager instance.
         * }
         */
        $data = apply_filters( 'customize_changeset_save_data', $data, $filter_context );

        // Switch theme if publishing changes now.
        if ( 'publish' === $args['status'] && ! $this->is_theme_active() ) {
            // Temporarily stop previewing the theme to allow switch_themes() to operate properly.
            $this->stop_previewing_theme();
            switch_theme( $this->get_stylesheet() );
            update_option( 'theme_switched_via_customizer', true );
            $this->start_previewing_theme();
        }

        // Gather the data for wp_insert_post()/wp_update_post().
        $json_options = 0;
        if ( defined( 'JSON_UNESCAPED_SLASHES' ) ) {
            $json_options |= JSON_UNESCAPED_SLASHES; // Introduced in PHP 5.4. This is only to improve readability as slashes needn't be escaped in storage.
        }
        $json_options |= JSON_PRETTY_PRINT; // Also introduced in PHP 5.4, but WP defines constant for back compat. See WP Trac #30139.
        $post_array = array(
            'post_content' => wp_json_encode( $data, $json_options ),
        );
        if ( $args['title'] ) {
            $post_array['post_title'] = $args['title'];
        }
        if ( $changeset_post_id ) {
            $post_array['ID'] = $changeset_post_id;
        } else {
            $post_array['post_type'] = 'customize_changeset';
            $post_array['post_name'] = $this->changeset_uuid();
            $post_array['post_status'] = 'auto-draft';
        }
        if ( $args['status'] ) {
            $post_array['post_status'] = $args['status'];
        }

        // Reset post date to now if we are publishing, otherwise pass post_date_gmt and translate for post_date.
        if ( 'publish' === $args['status'] ) {
            $post_array['post_date_gmt'] = '0000-00-00 00:00:00';
            $post_array['post_date'] = '0000-00-00 00:00:00';
        } elseif ( $args['date_gmt'] ) {
            $post_array['post_date_gmt'] = $args['date_gmt'];
            $post_array['post_date'] = get_date_from_gmt( $args['date_gmt'] );
        } elseif ( $changeset_post_id && 'auto-draft' === get_post_status( $changeset_post_id ) ) {
            /*
             * Keep bumping the date for the auto-draft whenever it is modified;
             * this extends its life, preserving it from garbage-collection via
             * wp_delete_auto_drafts().
             */
            $post_array['post_date'] = current_time( 'mysql' );
            $post_array['post_date_gmt'] = '';
        }

        $this->store_changeset_revision = $allow_revision;
        add_filter( 'wp_save_post_revision_post_has_changed', array( $this, '_filter_revision_post_has_changed' ), 5, 3 );

        // Update the changeset post. The publish_customize_changeset action will cause the settings in the changeset to be saved via WP_Customize_Setting::save().
        $has_kses = ( false !== has_filter( 'content_save_pre', 'wp_filter_post_kses' ) );
        if ( $has_kses ) {
            kses_remove_filters(); // Prevent KSES from corrupting JSON in post_content.
        }

        // Note that updating a post with publish status will trigger WP_Customize_Manager::publish_changeset_values().
        if ( $changeset_post_id ) {
            if ( $args['autosave'] && 'auto-draft' !== get_post_status( $changeset_post_id ) ) {
                // See _wp_translate_postdata() for why this is required as it will use the edit_post meta capability.
                add_filter( 'map_meta_cap', array( $this, 'grant_edit_post_capability_for_changeset' ), 10, 4 );
                $post_array['post_ID'] = $post_array['ID'];
                $post_array['post_type'] = 'customize_changeset';
                $r = wp_create_post_autosave( wp_slash( $post_array ) );
                remove_filter( 'map_meta_cap', array( $this, 'grant_edit_post_capability_for_changeset' ), 10 );
            } else {
                $post_array['edit_date'] = true; // Prevent date clearing.
                $r = wp_update_post( wp_slash( $post_array ), true );

                // Delete autosave revision for user when the changeset is updated.
                if ( ! empty( $args['user_id'] ) ) {
                    $autosave_draft = wp_get_post_autosave( $changeset_post_id, $args['user_id'] );
                    if ( $autosave_draft ) {
                        wp_delete_post( $autosave_draft->ID, true );
                    }
                }
            }
        } else {
            $r = wp_insert_post( wp_slash( $post_array ), true );
            if ( ! is_wp_error( $r ) ) {
                $this->_changeset_post_id = $r; // Update cached post ID for the loaded changeset.
            }
        }
        if ( $has_kses ) {
            kses_init_filters();
        }
        $this->_changeset_data = null; // Reset so WP_Customize_Manager::changeset_data() will re-populate with updated contents.

        remove_filter( 'wp_save_post_revision_post_has_changed', array( $this, '_filter_revision_post_has_changed' ) );

        $response = array(
            'setting_validities' => $setting_validities,
        );

        if ( is_wp_error( $r ) ) {
            $response['changeset_post_save_failure'] = $r->get_error_code();
            return new WP_Error( 'changeset_post_save_failure', '', $response );
        }

        return $response;
    }

    /**
     * Trash or delete a changeset post.
     *
     * The following re-formulates the logic from `wp_trash_post()` as done in
     * `wp_publish_post()`. The reason for bypassing `wp_trash_post()` is that it
     * will mutate the the `post_content` and the `post_name` when they should be
     * untouched.
     *
     * @since 4.9.0
     * @global wpdb $wpdb WordPress database abstraction object.
     * @see wp_trash_post()
     *
     * @param int|WP_Post $post The changeset post.
     * @return mixed A WP_Post object for the trashed post or an empty value on failure.
     */
    public function trash_changeset_post( $post ) {
        global $wpdb;

        $post = get_post( $post );

        if ( ! ( $post instanceof WP_Post ) ) {
            return $post;
        }
        $post_id = $post->ID;

        if ( ! EMPTY_TRASH_DAYS ) {
            return wp_delete_post( $post_id, true );
        }

        if ( 'trash' === get_post_status( $post ) ) {
            return false;
        }

        /** This filter is documented in wp-includes/post.php */
        $check = apply_filters( 'pre_trash_post', null, $post );
        if ( null !== $check ) {
            return $check;
        }

        /** This action is documented in wp-includes/post.php */
        do_action( 'wp_trash_post', $post_id );

        add_post_meta( $post_id, '_wp_trash_meta_status', $post->post_status );
        add_post_meta( $post_id, '_wp_trash_meta_time', time() );

        $old_status = $post->post_status;
        $new_status = 'trash';
        $wpdb->update( $wpdb->posts, array( 'post_status' => $new_status ), array( 'ID' => $post->ID ) );
        clean_post_cache( $post->ID );

        $post->post_status = $new_status;
        wp_transition_post_status( $new_status, $old_status, $post );

        /** This action is documented in wp-includes/post.php */
        do_action( 'edit_post', $post->ID, $post );

        /** This action is documented in wp-includes/post.php */
        do_action( "save_post_{$post->post_type}", $post->ID, $post, true );

        /** This action is documented in wp-includes/post.php */
        do_action( 'save_post', $post->ID, $post, true );

        /** This action is documented in wp-includes/post.php */
        do_action( 'wp_insert_post', $post->ID, $post, true );

        wp_trash_post_comments( $post_id );

        /** This action is documented in wp-includes/post.php */
        do_action( 'trashed_post', $post_id );

        return $post;
    }

    /**
     * Handle request to trash a changeset.
     *
     * @since 4.9.0
     */
    public function handle_changeset_trash_request() {
        if ( ! is_user_logged_in() ) {
            wp_send_json_error( 'unauthenticated' );
        }

        if ( ! $this->is_preview() ) {
            wp_send_json_error( 'not_preview' );
        }

        if ( ! check_ajax_referer( 'trash_customize_changeset', 'nonce', false ) ) {
            wp_send_json_error( array(
                'code' => 'invalid_nonce',
                'message' => __( 'There was an authentication problem. Please reload and try again.' ),
            ) );
        }

        $changeset_post_id = $this->changeset_post_id();

        if ( ! $changeset_post_id ) {
            wp_send_json_error( array(
                'message' => __( 'No changes saved yet, so there is nothing to trash.' ),
                'code' => 'non_existent_changeset',
            ) );
            return;
        }

        if ( $changeset_post_id && ! current_user_can( get_post_type_object( 'customize_changeset' )->cap->delete_post, $changeset_post_id ) ) {
            wp_send_json_error( array(
                'code' => 'changeset_trash_unauthorized',
                'message' => __( 'Unable to trash changes.' ),
            ) );
        }

        if ( 'trash' === get_post_status( $changeset_post_id ) ) {
            wp_send_json_error( array(
                'message' => __( 'Changes have already been trashed.' ),
                'code' => 'changeset_already_trashed',
            ) );
            return;
        }

        $r = $this->trash_changeset_post( $changeset_post_id );
        if ( ! ( $r instanceof WP_Post ) ) {
            wp_send_json_error( array(
                'code' => 'changeset_trash_failure',
                'message' => __( 'Unable to trash changes.' ),
            ) );
        }

        wp_send_json_success( array(
            'message' => __( 'Changes trashed successfully.' ),
        ) );
    }

    /**
     * Re-map 'edit_post' meta cap for a customize_changeset post to be the same as 'customize' maps.
     *
     * There is essentially a "meta meta" cap in play here, where 'edit_post' meta cap maps to
     * the 'customize' meta cap which then maps to 'edit_theme_options'. This is currently
     * required in core for `wp_create_post_autosave()` because it will call
     * `_wp_translate_postdata()` which in turn will check if a user can 'edit_post', but the
     * the caps for the customize_changeset post type are all mapping to the meta capability.
     * This should be able to be removed once #40922 is addressed in core.
     *
     * @since 4.9.0
     * @link https://core.trac.wordpress.org/ticket/40922
     * @see WP_Customize_Manager::save_changeset_post()
     * @see _wp_translate_postdata()
     *
     * @param array  $caps    Returns the user's actual capabilities.
     * @param string $cap     Capability name.
     * @param int    $user_id The user ID.
     * @param array  $args    Adds the context to the cap. Typically the object ID.
     * @return array Capabilities.
     */
    public function grant_edit_post_capability_for_changeset( $caps, $cap, $user_id, $args ) {
        if ( 'edit_post' === $cap && ! empty( $args[0] ) && 'customize_changeset' === get_post_type( $args[0] ) ) {
            $post_type_obj = get_post_type_object( 'customize_changeset' );
            $caps = map_meta_cap( $post_type_obj->cap->$cap, $user_id );
        }
        return $caps;
    }

    /**
     * Marks the changeset post as being currently edited by the current user.
     *
     * @since 4.9.0
     *
     * @param int  $changeset_post_id Changeset post id.
     * @param bool $take_over Take over the changeset, default is false.
     */
    public function set_changeset_lock( $changeset_post_id, $take_over = false ) {
        if ( $changeset_post_id ) {
            $can_override = ! (bool) get_post_meta( $changeset_post_id, '_edit_lock', true );

            if ( $take_over ) {
                $can_override = true;
            }

            if ( $can_override ) {
                $lock = sprintf( '%s:%s', time(), get_current_user_id() );
                update_post_meta( $changeset_post_id, '_edit_lock', $lock );
            } else {
                $this->refresh_changeset_lock( $changeset_post_id );
            }
        }
    }

    /**
     * Refreshes changeset lock with the current time if current user edited the changeset before.
     *
     * @since 4.9.0
     *
     * @param int $changeset_post_id Changeset post id.
     */
    public function refresh_changeset_lock( $changeset_post_id ) {
        if ( ! $changeset_post_id ) {
            return;
        }
        $lock = get_post_meta( $changeset_post_id, '_edit_lock', true );
        $lock = explode( ':', $lock );

        if ( $lock && ! empty( $lock[1] ) ) {
            $user_id = intval( $lock[1] );
            $current_user_id = get_current_user_id();
            if ( $user_id === $current_user_id ) {
                $lock = sprintf( '%s:%s', time(), $user_id );
                update_post_meta( $changeset_post_id, '_edit_lock', $lock );
            }
        }
    }

    /**
     * Filter heartbeat settings for the Customizer.
     *
     * @since 4.9.0
     * @param array $settings Current settings to filter.
     * @return array Heartbeat settings.
     */
    public function add_customize_screen_to_heartbeat_settings( $settings ) {
        global $pagenow;
        if ( 'customize.php' === $pagenow ) {
            $settings['screenId'] = 'customize';
        }
        return $settings;
    }

    /**
     * Get lock user data.
     *
     * @since 4.9.0
     *
     * @param int $user_id User ID.
     * @return array|null User data formatted for client.
     */
    protected function get_lock_user_data( $user_id ) {
        if ( ! $user_id ) {
            return null;
        }
        $lock_user = get_userdata( $user_id );
        if ( ! $lock_user ) {
            return null;
        }
        return array(
            'id' => $lock_user->ID,
            'name' => $lock_user->display_name,
            'avatar' => get_avatar_url( $lock_user->ID, array( 'size' => 128 ) ),
        );
    }

    /**
     * Check locked changeset with heartbeat API.
     *
     * @since 4.9.0
     *
     * @param array  $response  The Heartbeat response.
     * @param array  $data      The $_POST data sent.
     * @param string $screen_id The screen id.
     * @return array The Heartbeat response.
     */
    public function check_changeset_lock_with_heartbeat( $response, $data, $screen_id ) {
        if ( isset( $data['changeset_uuid'] ) ) {
            $changeset_post_id = $this->find_changeset_post_id( $data['changeset_uuid'] );
        } else {
            $changeset_post_id = $this->changeset_post_id();
        }

        if (
            array_key_exists( 'check_changeset_lock', $data )
            && 'customize' === $screen_id
            && $changeset_post_id
            && current_user_can( get_post_type_object( 'customize_changeset' )->cap->edit_post, $changeset_post_id )
        ) {
            $lock_user_id = wp_check_post_lock( $changeset_post_id );

            if ( $lock_user_id ) {
                $response['customize_changeset_lock_user'] = $this->get_lock_user_data( $lock_user_id );
            } else {

                // Refreshing time will ensure that the user is sitting on customizer and has not closed the customizer tab.
                $this->refresh_changeset_lock( $changeset_post_id );
            }
        }

        return $response;
    }

    /**
     * Removes changeset lock when take over request is sent via Ajax.
     *
     * @since 4.9.0
     */
    public function handle_override_changeset_lock_request() {
        if ( ! $this->is_preview() ) {
            wp_send_json_error( 'not_preview', 400 );
        }

        if ( ! check_ajax_referer( 'customize_override_changeset_lock', 'nonce', false ) ) {
            wp_send_json_error( array(
                'code' => 'invalid_nonce',
                'message' => __( 'Security check failed.' ),
            ) );
        }

        $changeset_post_id = $this->changeset_post_id();

        if ( empty( $changeset_post_id ) ) {
            wp_send_json_error( array(
                'code' => 'no_changeset_found_to_take_over',
                'message' => __( 'No changeset found to take over' ),
            ) );
        }

        if ( ! current_user_can( get_post_type_object( 'customize_changeset' )->cap->edit_post, $changeset_post_id ) ) {
            wp_send_json_error( array(
                'code' => 'cannot_remove_changeset_lock',
                'message' => __( 'Sorry, you are not allowed to take over.' ),
            ) );
        }

        $this->set_changeset_lock( $changeset_post_id, true );

        wp_send_json_success( 'changeset_taken_over' );
    }

    /**
     * Whether a changeset revision should be made.
     *
     * @since 4.7.0
     * @var bool
     */
    protected $store_changeset_revision;

    /**
     * Filters whether a changeset has changed to create a new revision.
     *
     * Note that this will not be called while a changeset post remains in auto-draft status.
     *
     * @since 4.7.0
     *
     * @param bool    $post_has_changed Whether the post has changed.
     * @param WP_Post $last_revision    The last revision post object.
     * @param WP_Post $post             The post object.
     *
     * @return bool Whether a revision should be made.
     */
    public function _filter_revision_post_has_changed( $post_has_changed, $last_revision, $post ) {
        unset( $last_revision );
        if ( 'customize_changeset' === $post->post_type ) {
            $post_has_changed = $this->store_changeset_revision;
        }
        return $post_has_changed;
    }

    /**
     * Publish changeset values.
     *
     * This will the values contained in a changeset, even changesets that do not
     * correspond to current manager instance. This is called by
     * `_wp_customize_publish_changeset()` when a customize_changeset post is
     * transitioned to the `publish` status. As such, this method should not be
     * called directly and instead `wp_publish_post()` should be used.
     *
     * Please note that if the settings in the changeset are for a non-activated
     * theme, the theme must first be switched to (via `switch_theme()`) before
     * invoking this method.
     *
     * @since 4.7.0
     * @see _wp_customize_publish_changeset()
     * @global wpdb $wpdb
     *
     * @param int $changeset_post_id ID for customize_changeset post. Defaults to the changeset for the current manager instance.
     * @return true|WP_Error True or error info.
     */
    public function _publish_changeset_values( $changeset_post_id ) {
        global $wpdb;

        $publishing_changeset_data = $this->get_changeset_post_data( $changeset_post_id );
        if ( is_wp_error( $publishing_changeset_data ) ) {
            return $publishing_changeset_data;
        }

        $changeset_post = get_post( $changeset_post_id );

        /*
         * Temporarily override the changeset context so that it will be read
         * in calls to unsanitized_post_values() and so that it will be available
         * on the $wp_customize object passed to hooks during the save logic.
         */
        $previous_changeset_post_id = $this->_changeset_post_id;
        $this->_changeset_post_id   = $changeset_post_id;
        $previous_changeset_uuid    = $this->_changeset_uuid;
        $this->_changeset_uuid      = $changeset_post->post_name;
        $previous_changeset_data    = $this->_changeset_data;
        $this->_changeset_data      = $publishing_changeset_data;

        // Parse changeset data to identify theme mod settings and user IDs associated with settings to be saved.
        $setting_user_ids = array();
        $theme_mod_settings = array();
        $namespace_pattern = '/^(?P<stylesheet>.+?)::(?P<setting_id>.+)$/';
        $matches = array();
        foreach ( $this->_changeset_data as $raw_setting_id => $setting_params ) {
            $actual_setting_id = null;
            $is_theme_mod_setting = (
                isset( $setting_params['value'] )
                &&
                isset( $setting_params['type'] )
                &&
                'theme_mod' === $setting_params['type']
                &&
                preg_match( $namespace_pattern, $raw_setting_id, $matches )
            );
            if ( $is_theme_mod_setting ) {
                if ( ! isset( $theme_mod_settings[ $matches['stylesheet'] ] ) ) {
                    $theme_mod_settings[ $matches['stylesheet'] ] = array();
                }
                $theme_mod_settings[ $matches['stylesheet'] ][ $matches['setting_id'] ] = $setting_params;

                if ( $this->get_stylesheet() === $matches['stylesheet'] ) {
                    $actual_setting_id = $matches['setting_id'];
                }
            } else {
                $actual_setting_id = $raw_setting_id;
            }

            // Keep track of the user IDs for settings actually for this theme.
            if ( $actual_setting_id && isset( $setting_params['user_id'] ) ) {
                $setting_user_ids[ $actual_setting_id ] = $setting_params['user_id'];
            }
        }

        $changeset_setting_values = $this->unsanitized_post_values( array(
            'exclude_post_data' => true,
            'exclude_changeset' => false,
        ) );
        $changeset_setting_ids = array_keys( $changeset_setting_values );
        $this->add_dynamic_settings( $changeset_setting_ids );

        /**
         * Fires once the theme has switched in the Customizer, but before settings
         * have been saved.
         *
         * @since 3.4.0
         *
         * @param WP_Customize_Manager $manager WP_Customize_Manager instance.
         */
        do_action( 'customize_save', $this );

        /*
         * Ensure that all settings will allow themselves to be saved. Note that
         * this is safe because the setting would have checked the capability
         * when the setting value was written into the changeset. So this is why
         * an additional capability check is not required here.
         */
        $original_setting_capabilities = array();
        foreach ( $changeset_setting_ids as $setting_id ) {
            $setting = $this->get_setting( $setting_id );
            if ( $setting && ! isset( $setting_user_ids[ $setting_id ] ) ) {
                $original_setting_capabilities[ $setting->id ] = $setting->capability;
                $setting->capability = 'exist';
            }
        }

        $original_user_id = get_current_user_id();
        foreach ( $changeset_setting_ids as $setting_id ) {
            $setting = $this->get_setting( $setting_id );
            if ( $setting ) {
                /*
                 * Set the current user to match the user who saved the value into
                 * the changeset so that any filters that apply during the save
                 * process will respect the original user's capabilities. This
                 * will ensure, for example, that KSES won't strip unsafe HTML
                 * when a scheduled changeset publishes via WP Cron.
                 */
                if ( isset( $setting_user_ids[ $setting_id ] ) ) {
                    wp_set_current_user( $setting_user_ids[ $setting_id ] );
                } else {
                    wp_set_current_user( $original_user_id );
                }

                $setting->save();
            }
        }
        wp_set_current_user( $original_user_id );

        // Update the stashed theme mod settings, removing the active theme's stashed settings, if activated.
        if ( did_action( 'switch_theme' ) ) {
            $other_theme_mod_settings = $theme_mod_settings;
            unset( $other_theme_mod_settings[ $this->get_stylesheet() ] );
            $this->update_stashed_theme_mod_settings( $other_theme_mod_settings );
        }

        /**
         * Fires after Customize settings have been saved.
         *
         * @since 3.6.0
         *
         * @param WP_Customize_Manager $manager WP_Customize_Manager instance.
         */
        do_action( 'customize_save_after', $this );

        // Restore original capabilities.
        foreach ( $original_setting_capabilities as $setting_id => $capability ) {
            $setting = $this->get_setting( $setting_id );
            if ( $setting ) {
                $setting->capability = $capability;
            }
        }

        // Restore original changeset data.
        $this->_changeset_data    = $previous_changeset_data;
        $this->_changeset_post_id = $previous_changeset_post_id;
        $this->_changeset_uuid    = $previous_changeset_uuid;

        /*
         * Convert all autosave revisions into their own auto-drafts so that users can be prompted to
         * restore them when a changeset is published, but they had been locked out from including
         * their changes in the changeset.
         */
        $revisions = wp_get_post_revisions( $changeset_post_id, array( 'check_enabled' => false ) );
        foreach ( $revisions as $revision ) {
            if ( false !== strpos( $revision->post_name, "{$changeset_post_id}-autosave" ) ) {
                $wpdb->update(
                    $wpdb->posts,
                    array(
                        'post_status' => 'auto-draft',
                        'post_type' => 'customize_changeset',
                        'post_name' => wp_generate_uuid4(),
                        'post_parent' => 0,
                    ),
                    array(
                        'ID' => $revision->ID,
                    )
                );
                clean_post_cache( $revision->ID );
            }
        }

        return true;
    }

    /**
     * Update stashed theme mod settings.
     *
     * @since 4.7.0
     *
     * @param array $inactive_theme_mod_settings Mapping of stylesheet to arrays of theme mod settings.
     * @return array|false Returns array of updated stashed theme mods or false if the update failed or there were no changes.
     */
    protected function update_stashed_theme_mod_settings( $inactive_theme_mod_settings ) {
        $stashed_theme_mod_settings = get_option( 'customize_stashed_theme_mods' );
        if ( empty( $stashed_theme_mod_settings ) ) {
            $stashed_theme_mod_settings = array();
        }

        // Delete any stashed theme mods for the active theme since they would have been loaded and saved upon activation.
        unset( $stashed_theme_mod_settings[ $this->get_stylesheet() ] );

        // Merge inactive theme mods with the stashed theme mod settings.
        foreach ( $inactive_theme_mod_settings as $stylesheet => $theme_mod_settings ) {
            if ( ! isset( $stashed_theme_mod_settings[ $stylesheet ] ) ) {
                $stashed_theme_mod_settings[ $stylesheet ] = array();
            }

            $stashed_theme_mod_settings[ $stylesheet ] = array_merge(
                $stashed_theme_mod_settings[ $stylesheet ],
                $theme_mod_settings
            );
        }

        $autoload = false;
        $result = update_option( 'customize_stashed_theme_mods', $stashed_theme_mod_settings, $autoload );
        if ( ! $result ) {
            return false;
        }
        return $stashed_theme_mod_settings;
    }

    /**
     * Refresh nonces for the current preview.
     *
     * @since 4.2.0
     */
    public function refresh_nonces() {
        if ( ! $this->is_preview() ) {
            wp_send_json_error( 'not_preview' );
        }

        wp_send_json_success( $this->get_nonces() );
    }

    /**
     * Delete a given auto-draft changeset or the autosave revision for a given changeset or delete changeset lock.
     *
     * @since 4.9.0
     */
    public function handle_dismiss_autosave_or_lock_request() {
        // Calls to dismiss_user_auto_draft_changesets() and wp_get_post_autosave() require non-zero get_current_user_id().
        if ( ! is_user_logged_in() ) {
            wp_send_json_error( 'unauthenticated', 401 );
        }

        if ( ! $this->is_preview() ) {
            wp_send_json_error( 'not_preview', 400 );
        }

        if ( ! check_ajax_referer( 'customize_dismiss_autosave_or_lock', 'nonce', false ) ) {
            wp_send_json_error( 'invalid_nonce', 403 );
        }

        $changeset_post_id = $this->changeset_post_id();
        $dismiss_lock = ! empty( $_POST['dismiss_lock'] );
        $dismiss_autosave = ! empty( $_POST['dismiss_autosave'] );

        if ( $dismiss_lock ) {
            if ( empty( $changeset_post_id ) && ! $dismiss_autosave ) {
                wp_send_json_error( 'no_changeset_to_dismiss_lock', 404 );
            }
            if ( ! current_user_can( get_post_type_object( 'customize_changeset' )->cap->edit_post, $changeset_post_id ) && ! $dismiss_autosave ) {
                wp_send_json_error( 'cannot_remove_changeset_lock', 403 );
            }

            delete_post_meta( $changeset_post_id, '_edit_lock' );

            if ( ! $dismiss_autosave ) {
                wp_send_json_success( 'changeset_lock_dismissed' );
            }
        }

        if ( $dismiss_autosave ) {
            if ( empty( $changeset_post_id ) || 'auto-draft' === get_post_status( $changeset_post_id ) ) {
                $dismissed = $this->dismiss_user_auto_draft_changesets();
                if ( $dismissed > 0 ) {
                    wp_send_json_success( 'auto_draft_dismissed' );
                } else {
                    wp_send_json_error( 'no_auto_draft_to_delete', 404 );
                }
            } else {
                $revision = wp_get_post_autosave( $changeset_post_id, get_current_user_id() );

                if ( $revision ) {
                    if ( ! current_user_can( get_post_type_object( 'customize_changeset' )->cap->delete_post, $changeset_post_id ) ) {
                        wp_send_json_error( 'cannot_delete_autosave_revision', 403 );
                    }

                    if ( ! wp_delete_post( $revision->ID, true ) ) {
                        wp_send_json_error( 'autosave_revision_deletion_failure', 500 );
                    } else {
                        wp_send_json_success( 'autosave_revision_deleted' );
                    }
                } else {
                    wp_send_json_error( 'no_autosave_revision_to_delete', 404 );
                }
            }
        }

        wp_send_json_error( 'unknown_error', 500 );
    }

    /**
     * Add a customize setting.
     *
     * @since 3.4.0
     * @since 4.5.0 Return added WP_Customize_Setting instance.
     *
     * @param WP_Customize_Setting|string $id   Customize Setting object, or ID.
     * @param array                       $args {
     *  Optional. Array of properties for the new WP_Customize_Setting. Default empty array.
     *
     *  @type string       $type                  Type of the setting. Default 'theme_mod'.
     *                                            Default 160.
     *  @type string       $capability            Capability required for the setting. Default 'edit_theme_options'
     *  @type string|array $theme_supports        Theme features required to support the panel. Default is none.
     *  @type string       $default               Default value for the setting. Default is empty string.
     *  @type string       $transport             Options for rendering the live preview of changes in Theme Customizer.
     *                                            Using 'refresh' makes the change visible by reloading the whole preview.
     *                                            Using 'postMessage' allows a custom JavaScript to handle live changes.
     *                                            @link https://developer.wordpress.org/themes/customize-api
     *                                            Default is 'refresh'
     *  @type callable     $validate_callback     Server-side validation callback for the setting's value.
     *  @type callable     $sanitize_callback     Callback to filter a Customize setting value in un-slashed form.
     *  @type callable     $sanitize_js_callback  Callback to convert a Customize PHP setting value to a value that is
     *                                            JSON serializable.
     *  @type bool         $dirty                 Whether or not the setting is initially dirty when created.
     * }
     * @return WP_Customize_Setting             The instance of the setting that was added.
     */
    public function add_setting( $id, $args = array() ) {
        if ( $id instanceof WP_Customize_Setting ) {
            $setting = $id;
        } else {
            $class = 'WP_Customize_Setting';

            /** This filter is documented in wp-includes/class-wp-customize-manager.php */
            $args = apply_filters( 'customize_dynamic_setting_args', $args, $id );

            /** This filter is documented in wp-includes/class-wp-customize-manager.php */
            $class = apply_filters( 'customize_dynamic_setting_class', $class, $id, $args );

            $setting = new $class( $this, $id, $args );
        }

        $this->settings[ $setting->id ] = $setting;
        return $setting;
    }

    /**
     * Register any dynamically-created settings, such as those from $_POST['customized']
     * that have no corresponding setting created.
     *
     * This is a mechanism to "wake up" settings that have been dynamically created
     * on the front end and have been sent to WordPress in `$_POST['customized']`. When WP
     * loads, the dynamically-created settings then will get created and previewed
     * even though they are not directly created statically with code.
     *
     * @since 4.2.0
     *
     * @param array $setting_ids The setting IDs to add.
     * @return array The WP_Customize_Setting objects added.
     */
    public function add_dynamic_settings( $setting_ids ) {
        $new_settings = array();
        foreach ( $setting_ids as $setting_id ) {
            // Skip settings already created
            if ( $this->get_setting( $setting_id ) ) {
                continue;
            }

            $setting_args = false;
            $setting_class = 'WP_Customize_Setting';

            /**
             * Filters a dynamic setting's constructor args.
             *
             * For a dynamic setting to be registered, this filter must be employed
             * to override the default false value with an array of args to pass to
             * the WP_Customize_Setting constructor.
             *
             * @since 4.2.0
             *
             * @param false|array $setting_args The arguments to the WP_Customize_Setting constructor.
             * @param string      $setting_id   ID for dynamic setting, usually coming from `$_POST['customized']`.
             */
            $setting_args = apply_filters( 'customize_dynamic_setting_args', $setting_args, $setting_id );
            if ( false === $setting_args ) {
                continue;
            }

            /**
             * Allow non-statically created settings to be constructed with custom WP_Customize_Setting subclass.
             *
             * @since 4.2.0
             *
             * @param string $setting_class WP_Customize_Setting or a subclass.
             * @param string $setting_id    ID for dynamic setting, usually coming from `$_POST['customized']`.
             * @param array  $setting_args  WP_Customize_Setting or a subclass.
             */
            $setting_class = apply_filters( 'customize_dynamic_setting_class', $setting_class, $setting_id, $setting_args );

            $setting = new $setting_class( $this, $setting_id, $setting_args );

            $this->add_setting( $setting );
            $new_settings[] = $setting;
        }
        return $new_settings;
    }

    /**
     * Retrieve a customize setting.
     *
     * @since 3.4.0
     *
     * @param string $id Customize Setting ID.
     * @return WP_Customize_Setting|void The setting, if set.
     */
    public function get_setting( $id ) {
        if ( isset( $this->settings[ $id ] ) ) {
            return $this->settings[ $id ];
        }
    }

    /**
     * Remove a customize setting.
     *
     * @since 3.4.0
     *
     * @param string $id Customize Setting ID.
     */
    public function remove_setting( $id ) {
        unset( $this->settings[ $id ] );
    }

    /**
     * Add a customize panel.
     *
     * @since 4.0.0
     * @since 4.5.0 Return added WP_Customize_Panel instance.
     *
     * @param WP_Customize_Panel|string $id   Customize Panel object, or Panel ID.
     * @param array                     $args {
     *  Optional. Array of properties for the new Panel object. Default empty array.
     *  @type int          $priority              Priority of the panel, defining the display order of panels and sections.
     *                                            Default 160.
     *  @type string       $capability            Capability required for the panel. Default `edit_theme_options`
     *  @type string|array $theme_supports        Theme features required to support the panel.
     *  @type string       $title                 Title of the panel to show in UI.
     *  @type string       $description           Description to show in the UI.
     *  @type string       $type                  Type of the panel.
     *  @type callable     $active_callback       Active callback.
     * }
     * @return WP_Customize_Panel             The instance of the panel that was added.
     */
    public function add_panel( $id, $args = array() ) {
        if ( $id instanceof WP_Customize_Panel ) {
            $panel = $id;
        } else {
            $panel = new WP_Customize_Panel( $this, $id, $args );
        }

        $this->panels[ $panel->id ] = $panel;
        return $panel;
    }

    /**
     * Retrieve a customize panel.
     *
     * @since 4.0.0
     *
     * @param string $id Panel ID to get.
     * @return WP_Customize_Panel|void Requested panel instance, if set.
     */
    public function get_panel( $id ) {
        if ( isset( $this->panels[ $id ] ) ) {
            return $this->panels[ $id ];
        }
    }

    /**
     * Remove a customize panel.
     *
     * @since 4.0.0
     *
     * @param string $id Panel ID to remove.
     */
    public function remove_panel( $id ) {
        // Removing core components this way is _doing_it_wrong().
        if ( in_array( $id, $this->components, true ) ) {
            /* translators: 1: panel id, 2: link to 'customize_loaded_components' filter reference */
            $message = sprintf( __( 'Removing %1$s manually will cause PHP warnings. Use the %2$s filter instead.' ),
                $id,
                '<a href="' . esc_url( 'https://developer.wordpress.org/reference/hooks/customize_loaded_components/' ) . '"><code>customize_loaded_components</code></a>'
            );

            _doing_it_wrong( __METHOD__, $message, '4.5.0' );
        }
        unset( $this->panels[ $id ] );
    }

    /**
     * Register a customize panel type.
     *
     * Registered types are eligible to be rendered via JS and created dynamically.
     *
     * @since 4.3.0
     *
     * @see WP_Customize_Panel
     *
     * @param string $panel Name of a custom panel which is a subclass of WP_Customize_Panel.
     */
    public function register_panel_type( $panel ) {
        $this->registered_panel_types[] = $panel;
    }

    /**
     * Render JS templates for all registered panel types.
     *
     * @since 4.3.0
     */
    public function render_panel_templates() {
        foreach ( $this->registered_panel_types as $panel_type ) {
            $panel = new $panel_type( $this, 'temp', array() );
            $panel->print_template();
        }
    }

    /**
     * Add a customize section.
     *
     * @since 3.4.0
     * @since 4.5.0 Return added WP_Customize_Section instance.
     *
     * @param WP_Customize_Section|string $id   Customize Section object, or Section ID.
     * @param array                     $args {
     *  Optional. Array of properties for the new Section object. Default empty array.
     *  @type int          $priority              Priority of the section, defining the display order of panels and sections.
     *                                            Default 160.
     *  @type string       $panel                 The panel this section belongs to (if any). Default empty.
     *  @type string       $capability            Capability required for the section. Default 'edit_theme_options'
     *  @type string|array $theme_supports        Theme features required to support the section.
     *  @type string       $title                 Title of the section to show in UI.
     *  @type string       $description           Description to show in the UI.
     *  @type string       $type                  Type of the section.
     *  @type callable     $active_callback       Active callback.
     *  @type bool         $description_hidden    Hide the description behind a help icon, instead of inline above the first control. Default false.
     * }
     * @return WP_Customize_Section             The instance of the section that was added.
     */
    public function add_section( $id, $args = array() ) {
        if ( $id instanceof WP_Customize_Section ) {
            $section = $id;
        } else {
            $section = new WP_Customize_Section( $this, $id, $args );
        }

        $this->sections[ $section->id ] = $section;
        return $section;
    }

    /**
     * Retrieve a customize section.
     *
     * @since 3.4.0
     *
     * @param string $id Section ID.
     * @return WP_Customize_Section|void The section, if set.
     */
    public function get_section( $id ) {
        if ( isset( $this->sections[ $id ] ) )
            return $this->sections[ $id ];
    }

    /**
     * Remove a customize section.
     *
     * @since 3.4.0
     *
     * @param string $id Section ID.
     */
    public function remove_section( $id ) {
        unset( $this->sections[ $id ] );
    }

    /**
     * Register a customize section type.
     *
     * Registered types are eligible to be rendered via JS and created dynamically.
     *
     * @since 4.3.0
     *
     * @see WP_Customize_Section
     *
     * @param string $section Name of a custom section which is a subclass of WP_Customize_Section.
     */
    public function register_section_type( $section ) {
        $this->registered_section_types[] = $section;
    }

    /**
     * Render JS templates for all registered section types.
     *
     * @since 4.3.0
     */
    public function render_section_templates() {
        foreach ( $this->registered_section_types as $section_type ) {
            $section = new $section_type( $this, 'temp', array() );
            $section->print_template();
        }
    }

    /**
     * Add a customize control.
     *
     * @since 3.4.0
     * @since 4.5.0 Return added WP_Customize_Control instance.
     *
     * @param WP_Customize_Control|string $id   Customize Control object, or ID.
     * @param array                       $args {
     *  Optional. Array of properties for the new Control object. Default empty array.
     *
     *  @type array        $settings              All settings tied to the control. If undefined, defaults to `$setting`.
     *                                            IDs in the array correspond to the ID of a registered `WP_Customize_Setting`.
     *  @type string       $setting               The primary setting for the control (if there is one). Default is 'default'.
     *  @type string       $capability            Capability required to use this control. Normally derived from `$settings`.
     *  @type int          $priority              Order priority to load the control. Default 10.
     *  @type string       $section               The section this control belongs to. Default empty.
     *  @type string       $label                 Label for the control. Default empty.
     *  @type string       $description           Description for the control. Default empty.
     *  @type array        $choices               List of choices for 'radio' or 'select' type controls, where values
     *                                            are the keys, and labels are the values. Default empty array.
     *  @type array        $input_attrs           List of custom input attributes for control output, where attribute
     *                                            names are the keys and values are the values. Default empty array.
     *  @type bool         $allow_addition        Show UI for adding new content, currently only used for the
     *                                            dropdown-pages control. Default false.
     *  @type string       $type                  The type of the control. Default 'text'.
     *  @type callback     $active_callback       Active callback.
     * }
     * @return WP_Customize_Control             The instance of the control that was added.
     */
    public function add_control( $id, $args = array() ) {
        if ( $id instanceof WP_Customize_Control ) {
            $control = $id;
        } else {
            $control = new WP_Customize_Control( $this, $id, $args );
        }

        $this->controls[ $control->id ] = $control;
        return $control;
    }

    /**
     * Retrieve a customize control.
     *
     * @since 3.4.0
     *
     * @param string $id ID of the control.
     * @return WP_Customize_Control|void The control object, if set.
     */
    public function get_control( $id ) {
        if ( isset( $this->controls[ $id ] ) )
            return $this->controls[ $id ];
    }

    /**
     * Remove a customize control.
     *
     * @since 3.4.0
     *
     * @param string $id ID of the control.
     */
    public function remove_control( $id ) {
        unset( $this->controls[ $id ] );
    }

    /**
     * Register a customize control type.
     *
     * Registered types are eligible to be rendered via JS and created dynamically.
     *
     * @since 4.1.0
     *
     * @param string $control Name of a custom control which is a subclass of
     *                        WP_Customize_Control.
     */
    public function register_control_type( $control ) {
        $this->registered_control_types[] = $control;
    }

    /**
     * Render JS templates for all registered control types.
     *
     * @since 4.1.0
     */
    public function render_control_templates() {
        if ( $this->branching() ) {
            $l10n = array(
                /* translators: %s: User who is customizing the changeset in customizer. */
                'locked' => __( '%s is already customizing this changeset. Please wait until they are done to try customizing. Your latest changes have been autosaved.' ),
                /* translators: %s: User who is customizing the changeset in customizer. */
                'locked_allow_override' => __( '%s is already customizing this changeset. Do you want to take over?' ),
            );
        } else {
            $l10n = array(
                /* translators: %s: User who is customizing the changeset in customizer. */
                'locked' => __( '%s is already customizing this site. Please wait until they are done to try customizing. Your latest changes have been autosaved.' ),
                /* translators: %s: User who is customizing the changeset in customizer. */
                'locked_allow_override' => __( '%s is already customizing this site. Do you want to take over?' ),
            );
        }

        foreach ( $this->registered_control_types as $control_type ) {
            $control = new $control_type( $this, 'temp', array(
                'settings' => array(),
            ) );
            $control->print_template();
        }
        ?>

        <script type="text/html" id="tmpl-customize-control-default-content">
            <#
            var inputId = _.uniqueId( 'customize-control-default-input-' );
            var descriptionId = _.uniqueId( 'customize-control-default-description-' );
            var describedByAttr = data.description ? ' aria-describedby="' + descriptionId + '" ' : '';
            #>
            <# switch ( data.type ) {
                case 'checkbox': #>
                    <span class="customize-inside-control-row">
                        <input
                            id="{{ inputId }}"
                            {{{ describedByAttr }}}
                            type="checkbox"
                            value="{{ data.value }}"
                            data-customize-setting-key-link="default"
                        >
                        <label for="{{ inputId }}">
                            {{ data.label }}
                        </label>
                        <# if ( data.description ) { #>
                            <span id="{{ descriptionId }}" class="description customize-control-description">{{{ data.description }}}</span>
                        <# } #>
                    </span>
                    <#
                    break;
                case 'radio':
                    if ( ! data.choices ) {
                        return;
                    }
                    #>
                    <# if ( data.label ) { #>
                        <label for="{{ inputId }}" class="customize-control-title">
                            {{ data.label }}
                        </label>
                    <# } #>
                    <# if ( data.description ) { #>
                        <span id="{{ descriptionId }}" class="description customize-control-description">{{{ data.description }}}</span>
                    <# } #>
                    <# _.each( data.choices, function( val, key ) { #>
                        <span class="customize-inside-control-row">
                            <#
                            var value, text;
                            if ( _.isObject( val ) ) {
                                value = val.value;
                                text = val.text;
                            } else {
                                value = key;
                                text = val;
                            }
                            #>
                            <input
                                id="{{ inputId + '-' + value }}"
                                type="radio"
                                value="{{ value }}"
                                name="{{ inputId }}"
                                data-customize-setting-key-link="default"
                                {{{ describedByAttr }}}
                            >
                            <label for="{{ inputId + '-' + value }}">{{ text }}</label>
                        </span>
                    <# } ); #>
                    <#
                    break;
                default:
                    #>
                    <# if ( data.label ) { #>
                        <label for="{{ inputId }}" class="customize-control-title">
                            {{ data.label }}
                        </label>
                    <# } #>
                    <# if ( data.description ) { #>
                        <span id="{{ descriptionId }}" class="description customize-control-description">{{{ data.description }}}</span>
                    <# } #>

                    <#
                    var inputAttrs = {
                        id: inputId,
                        'data-customize-setting-key-link': 'default'
                    };
                    if ( 'textarea' === data.type ) {
                        inputAttrs.rows = '5';
                    } else if ( 'button' === data.type ) {
                        inputAttrs['class'] = 'button button-secondary';
                        inputAttrs.type = 'button';
                    } else {
                        inputAttrs.type = data.type;
                    }
                    if ( data.description ) {
                        inputAttrs['aria-describedby'] = descriptionId;
                    }
                    _.extend( inputAttrs, data.input_attrs );
                    #>

                    <# if ( 'button' === data.type ) { #>
                        <button
                            <# _.each( _.extend( inputAttrs ), function( value, key ) { #>
                                {{{ key }}}="{{ value }}"
                            <# } ); #>
                        >{{ inputAttrs.value }}</button>
                    <# } else if ( 'textarea' === data.type ) { #>
                        <textarea
                            <# _.each( _.extend( inputAttrs ), function( value, key ) { #>
                                {{{ key }}}="{{ value }}"
                            <# }); #>
                        >{{ inputAttrs.value }}</textarea>
                    <# } else if ( 'select' === data.type ) { #>
                        <# delete inputAttrs.type; #>
                        <select
                            <# _.each( _.extend( inputAttrs ), function( value, key ) { #>
                                {{{ key }}}="{{ value }}"
                            <# }); #>
                            >
                            <# _.each( data.choices, function( val, key ) { #>
                                <#
                                var value, text;
                                if ( _.isObject( val ) ) {
                                    value = val.value;
                                    text = val.text;
                                } else {
                                    value = key;
                                    text = val;
                                }
                                #>
                                <option value="{{ value }}">{{ text }}</option>
                            <# } ); #>
                        </select>
                    <# } else { #>
                        <input
                            <# _.each( _.extend( inputAttrs ), function( value, key ) { #>
                                {{{ key }}}="{{ value }}"
                            <# }); #>
                            >
                    <# } #>
            <# } #>
        </script>

        <script type="text/html" id="tmpl-customize-notification">
            <li class="notice notice-{{ data.type || 'info' }} {{ data.alt ? 'notice-alt' : '' }} {{ data.dismissible ? 'is-dismissible' : '' }} {{ data.containerClasses || '' }}" data-code="{{ data.code }}" data-type="{{ data.type }}">
                <div class="notification-message">{{{ data.message || data.code }}}</div>
                <# if ( data.dismissible ) { #>
                    <button type="button" class="notice-dismiss"><span class="screen-reader-text"><?php _e( 'Dismiss' ); ?></span></button>
                <# } #>
            </li>
        </script>

        <script type="text/html" id="tmpl-customize-changeset-locked-notification">
            <li class="notice notice-{{ data.type || 'info' }} {{ data.containerClasses || '' }}" data-code="{{ data.code }}" data-type="{{ data.type }}">
                <div class="notification-message customize-changeset-locked-message">
                    <img class="customize-changeset-locked-avatar" src="{{ data.lockUser.avatar }}" alt="{{ data.lockUser.name }}">
                    <p class="currently-editing">
                        <# if ( data.message ) { #>
                            {{{ data.message }}}
                        <# } else if ( data.allowOverride ) { #>
                            <?php
                            echo esc_html( sprintf( $l10n['locked_allow_override'], '{{ data.lockUser.name }}' ) );
                            ?>
                        <# } else { #>
                            <?php
                            echo esc_html( sprintf( $l10n['locked'], '{{ data.lockUser.name }}' ) );
                            ?>
                        <# } #>
                    </p>
                    <p class="notice notice-error notice-alt" hidden></p>
                    <p class="action-buttons">
                        <# if ( data.returnUrl !== data.previewUrl ) { #>
                            <a class="button customize-notice-go-back-button" href="{{ data.returnUrl }}"><?php _e( 'Go back' ); ?></a>
                        <# } #>
                        <a class="button customize-notice-preview-button" href="{{ data.frontendPreviewUrl }}"><?php _e( 'Preview' ); ?></a>
                        <# if ( data.allowOverride ) { #>
                            <button class="button button-primary wp-tab-last customize-notice-take-over-button"><?php _e( 'Take over' ); ?></button>
                        <# } #>
                    </p>
                </div>
            </li>
        </script>

        <script type="text/html" id="tmpl-customize-code-editor-lint-error-notification">
            <li class="notice notice-{{ data.type || 'info' }} {{ data.alt ? 'notice-alt' : '' }} {{ data.dismissible ? 'is-dismissible' : '' }} {{ data.containerClasses || '' }}" data-code="{{ data.code }}" data-type="{{ data.type }}">
                <div class="notification-message">{{{ data.message || data.code }}}</div>

                <p>
                    <# var elementId = 'el-' + String( Math.random() ); #>
                    <input id="{{ elementId }}" type="checkbox">
                    <label for="{{ elementId }}"><?php _e( 'Update anyway, even though it might break your site?' ); ?></label>
                </p>
            </li>
        </script>

        <?php
        /* The following template is obsolete in core but retained for plugins. */
        ?>
        <script type="text/html" id="tmpl-customize-control-notifications">
            <ul>
                <# _.each( data.notifications, function( notification ) { #>
                    <li class="notice notice-{{ notification.type || 'info' }} {{ data.altNotice ? 'notice-alt' : '' }}" data-code="{{ notification.code }}" data-type="{{ notification.type }}">{{{ notification.message || notification.code }}}</li>
                <# } ); #>
            </ul>
        </script>

        <script type="text/html" id="tmpl-customize-preview-link-control" >
            <# var elementPrefix = _.uniqueId( 'el' ) + '-' #>
            <p class="customize-control-title">
                <?php esc_html_e( 'Share Preview Link' ); ?>
            </p>
            <p class="description customize-control-description"><?php esc_html_e( 'See how changes would look live on your website, and share the preview with people who can\'t access the Customizer.' ); ?></p>
            <div class="customize-control-notifications-container"></div>
            <div class="preview-link-wrapper">
                <label for="{{ elementPrefix }}customize-preview-link-input" class="screen-reader-text"><?php esc_html_e( 'Preview Link' ); ?></label>
                <a href="" target="">
                    <span class="preview-control-element" data-component="url"></span>
                    <span class="screen-reader-text"><?php _e( '(opens in a new window)' ); ?></span>
                </a>
                <input id="{{ elementPrefix }}customize-preview-link-input" readonly tabindex="-1" class="preview-control-element" data-component="input">
                <button class="customize-copy-preview-link preview-control-element button button-secondary" data-component="button" data-copy-text="<?php esc_attr_e( 'Copy' ); ?>" data-copied-text="<?php esc_attr_e( 'Copied' ); ?>" ><?php esc_html_e( 'Copy' ); ?></button>
            </div>
        </script>
        <script type="text/html" id="tmpl-customize-selected-changeset-status-control">
            <# var inputId = _.uniqueId( 'customize-selected-changeset-status-control-input-' ); #>
            <# var descriptionId = _.uniqueId( 'customize-selected-changeset-status-control-description-' ); #>
            <# if ( data.label ) { #>
                <label for="{{ inputId }}" class="customize-control-title">{{ data.label }}</label>
            <# } #>
            <# if ( data.description ) { #>
                <span id="{{ descriptionId }}" class="description customize-control-description">{{{ data.description }}}</span>
            <# } #>
            <# _.each( data.choices, function( choice ) { #>
                <# var choiceId = inputId + '-' + choice.status; #>
                <span class="customize-inside-control-row">
                    <input id="{{ choiceId }}" type="radio" value="{{ choice.status }}" name="{{ inputId }}" data-customize-setting-key-link="default">
                    <label for="{{ choiceId }}">{{ choice.label }}</label>
                </span>
            <# } ); #>
        </script>
        <?php
    }

    /**
     * Helper function to compare two objects by priority, ensuring sort stability via instance_number.
     *
     * @since 3.4.0
     * @deprecated 4.7.0 Use wp_list_sort()
     *
     * @param WP_Customize_Panel|WP_Customize_Section|WP_Customize_Control $a Object A.
     * @param WP_Customize_Panel|WP_Customize_Section|WP_Customize_Control $b Object B.
     * @return int
     */
    protected function _cmp_priority( $a, $b ) {
        _deprecated_function( __METHOD__, '4.7.0', 'wp_list_sort' );

        if ( $a->priority === $b->priority ) {
            return $a->instance_number - $b->instance_number;
        } else {
            return $a->priority - $b->priority;
        }
    }

    /**
     * Prepare panels, sections, and controls.
     *
     * For each, check if required related components exist,
     * whether the user has the necessary capabilities,
     * and sort by priority.
     *
     * @since 3.4.0
     */
    public function prepare_controls() {

        $controls = array();
        $this->controls = wp_list_sort( $this->controls, array(
            'priority'        => 'ASC',
            'instance_number' => 'ASC',
        ), 'ASC', true );

        foreach ( $this->controls as $id => $control ) {
            if ( ! isset( $this->sections[ $control->section ] ) || ! $control->check_capabilities() ) {
                continue;
            }

            $this->sections[ $control->section ]->controls[] = $control;
            $controls[ $id ] = $control;
        }
        $this->controls = $controls;

        // Prepare sections.
        $this->sections = wp_list_sort( $this->sections, array(
            'priority'        => 'ASC',
            'instance_number' => 'ASC',
        ), 'ASC', true );
        $sections = array();

        foreach ( $this->sections as $section ) {
            if ( ! $section->check_capabilities() ) {
                continue;
            }


            $section->controls = wp_list_sort( $section->controls, array(
                'priority'        => 'ASC',
                'instance_number' => 'ASC',
            ) );

            if ( ! $section->panel ) {
                // Top-level section.
                $sections[ $section->id ] = $section;
            } else {
                // This section belongs to a panel.
                if ( isset( $this->panels [ $section->panel ] ) ) {
                    $this->panels[ $section->panel ]->sections[ $section->id ] = $section;
                }
            }
        }
        $this->sections = $sections;

        // Prepare panels.
        $this->panels = wp_list_sort( $this->panels, array(
            'priority'        => 'ASC',
            'instance_number' => 'ASC',
        ), 'ASC', true );
        $panels = array();

        foreach ( $this->panels as $panel ) {
            if ( ! $panel->check_capabilities() ) {
                continue;
            }

            $panel->sections = wp_list_sort( $panel->sections, array(
                'priority'        => 'ASC',
                'instance_number' => 'ASC',
            ), 'ASC', true );
            $panels[ $panel->id ] = $panel;
        }
        $this->panels = $panels;

        // Sort panels and top-level sections together.
        $this->containers = array_merge( $this->panels, $this->sections );
        $this->containers = wp_list_sort( $this->containers, array(
            'priority'        => 'ASC',
            'instance_number' => 'ASC',
        ), 'ASC', true );
    }

    /**
     * Enqueue scripts for customize controls.
     *
     * @since 3.4.0
     */
    public function enqueue_control_scripts() {
        foreach ( $this->controls as $control ) {
            $control->enqueue();
        }

        if ( ! is_multisite() && ( current_user_can( 'install_themes' ) || current_user_can( 'update_themes' ) || current_user_can( 'delete_themes' ) ) ) {
            wp_enqueue_script( 'updates' );
            wp_localize_script( 'updates', '_wpUpdatesItemCounts', array(
                'totals' => wp_get_update_data(),
            ) );
        }
    }

    /**
     * Determine whether the user agent is iOS.
     *
     * @since 4.4.0
     *
     * @return bool Whether the user agent is iOS.
     */
    public function is_ios() {
        return wp_is_mobile() && preg_match( '/iPad|iPod|iPhone/', $_SERVER['HTTP_USER_AGENT'] );
    }

    /**
     * Get the template string for the Customizer pane document title.
     *
     * @since 4.4.0
     *
     * @return string The template string for the document title.
     */
    public function get_document_title_template() {
        if ( $this->is_theme_active() ) {
            /* translators: %s: document title from the preview */
            $document_title_tmpl = __( 'Customize: %s' );
        } else {
            /* translators: %s: document title from the preview */
            $document_title_tmpl = __( 'Live Preview: %s' );
        }
        $document_title_tmpl = html_entity_decode( $document_title_tmpl, ENT_QUOTES, 'UTF-8' ); // Because exported to JS and assigned to document.title.
        return $document_title_tmpl;
    }

    /**
     * Set the initial URL to be previewed.
     *
     * URL is validated.
     *
     * @since 4.4.0
     *
     * @param string $preview_url URL to be previewed.
     */
    public function set_preview_url( $preview_url ) {
        $preview_url = esc_url_raw( $preview_url );
        $this->preview_url = wp_validate_redirect( $preview_url, home_url( '/' ) );
    }

    /**
     * Get the initial URL to be previewed.
     *
     * @since 4.4.0
     *
     * @return string URL being previewed.
     */
    public function get_preview_url() {
        if ( empty( $this->preview_url ) ) {
            $preview_url = home_url( '/' );
        } else {
            $preview_url = $this->preview_url;
        }
        return $preview_url;
    }

    /**
     * Determines whether the admin and the frontend are on different domains.
     *
     * @since 4.7.0
     *
     * @return bool Whether cross-domain.
     */
    public function is_cross_domain() {
        $admin_origin = wp_parse_url( admin_url() );
        $home_origin = wp_parse_url( home_url() );
        $cross_domain = ( strtolower( $admin_origin['host'] ) !== strtolower( $home_origin['host'] ) );
        return $cross_domain;
    }

    /**
     * Get URLs allowed to be previewed.
     *
     * If the front end and the admin are served from the same domain, load the
     * preview over ssl if the Customizer is being loaded over ssl. This avoids
     * insecure content warnings. This is not attempted if the admin and front end
     * are on different domains to avoid the case where the front end doesn't have
     * ssl certs. Domain mapping plugins can allow other urls in these conditions
     * using the customize_allowed_urls filter.
     *
     * @since 4.7.0
     *
     * @returns array Allowed URLs.
     */
    public function get_allowed_urls() {
        $allowed_urls = array( home_url( '/' ) );

        if ( is_ssl() && ! $this->is_cross_domain() ) {
            $allowed_urls[] = home_url( '/', 'https' );
        }

        /**
         * Filters the list of URLs allowed to be clicked and followed in the Customizer preview.
         *
         * @since 3.4.0
         *
         * @param array $allowed_urls An array of allowed URLs.
         */
        $allowed_urls = array_unique( apply_filters( 'customize_allowed_urls', $allowed_urls ) );

        return $allowed_urls;
    }

    /**
     * Get messenger channel.
     *
     * @since 4.7.0
     *
     * @return string Messenger channel.
     */
    public function get_messenger_channel() {
        return $this->messenger_channel;
    }

    /**
     * Set URL to link the user to when closing the Customizer.
     *
     * URL is validated.
     *
     * @since 4.4.0
     *
     * @param string $return_url URL for return link.
     */
    public function set_return_url( $return_url ) {
        $return_url = esc_url_raw( $return_url );
        $return_url = remove_query_arg( wp_removable_query_args(), $return_url );
        $return_url = wp_validate_redirect( $return_url );
        $this->return_url = $return_url;
    }

    /**
     * Get URL to link the user to when closing the Customizer.
     *
     * @since 4.4.0
     *
     * @return string URL for link to close Customizer.
     */
    public function get_return_url() {
        $referer = wp_get_referer();
        $excluded_referer_basenames = array( 'customize.php', 'wp-login.php' );

        if ( $this->return_url ) {
            $return_url = $this->return_url;
        } else if ( $referer && ! in_array( basename( parse_url( $referer, PHP_URL_PATH ) ), $excluded_referer_basenames, true ) ) {
            $return_url = $referer;
        } else if ( $this->preview_url ) {
            $return_url = $this->preview_url;
        } else {
            $return_url = home_url( '/' );
        }
        return $return_url;
    }

    /**
     * Set the autofocused constructs.
     *
     * @since 4.4.0
     *
     * @param array $autofocus {
     *     Mapping of 'panel', 'section', 'control' to the ID which should be autofocused.
     *
     *     @type string [$control]  ID for control to be autofocused.
     *     @type string [$section]  ID for section to be autofocused.
     *     @type string [$panel]    ID for panel to be autofocused.
     * }
     */
    public function set_autofocus( $autofocus ) {
        $this->autofocus = array_filter( wp_array_slice_assoc( $autofocus, array( 'panel', 'section', 'control' ) ), 'is_string' );
    }

    /**
     * Get the autofocused constructs.
     *
     * @since 4.4.0
     *
     * @return array {
     *     Mapping of 'panel', 'section', 'control' to the ID which should be autofocused.
     *
     *     @type string [$control]  ID for control to be autofocused.
     *     @type string [$section]  ID for section to be autofocused.
     *     @type string [$panel]    ID for panel to be autofocused.
     * }
     */
    public function get_autofocus() {
        return $this->autofocus;
    }

    /**
     * Get nonces for the Customizer.
     *
     * @since 4.5.0
     *
     * @return array Nonces.
     */
    public function get_nonces() {
        $nonces = array(
            'save' => wp_create_nonce( 'save-customize_' . $this->get_stylesheet() ),
            'preview' => wp_create_nonce( 'preview-customize_' . $this->get_stylesheet() ),
            'switch_themes' => wp_create_nonce( 'switch_themes' ),
            'dismiss_autosave_or_lock' => wp_create_nonce( 'customize_dismiss_autosave_or_lock' ),
            'override_lock' => wp_create_nonce( 'customize_override_changeset_lock' ),
            'trash' => wp_create_nonce( 'trash_customize_changeset' ),
        );

        /**
         * Filters nonces for Customizer.
         *
         * @since 4.2.0
         *
         * @param array                $nonces Array of refreshed nonces for save and
         *                                     preview actions.
         * @param WP_Customize_Manager $this   WP_Customize_Manager instance.
         */
        $nonces = apply_filters( 'customize_refresh_nonces', $nonces, $this );

        return $nonces;
    }

    /**
     * Print JavaScript settings for parent window.
     *
     * @since 4.4.0
     */
    public function customize_pane_settings() {

        $login_url = add_query_arg( array(
            'interim-login' => 1,
            'customize-login' => 1,
        ), wp_login_url() );

        // Ensure dirty flags are set for modified settings.
        foreach ( array_keys( $this->unsanitized_post_values() ) as $setting_id ) {
            $setting = $this->get_setting( $setting_id );
            if ( $setting ) {
                $setting->dirty = true;
            }
        }

        $autosave_revision_post = null;
        $autosave_autodraft_post = null;
        $changeset_post_id = $this->changeset_post_id();
        if ( ! $this->saved_starter_content_changeset && ! $this->autosaved() ) {
            if ( $changeset_post_id ) {
                if ( is_user_logged_in() ) {
                    $autosave_revision_post = wp_get_post_autosave( $changeset_post_id, get_current_user_id() );
                }
            } else {
                $autosave_autodraft_posts = $this->get_changeset_posts( array(
                    'posts_per_page' => 1,
                    'post_status' => 'auto-draft',
                    'exclude_restore_dismissed' => true,
                ) );
                if ( ! empty( $autosave_autodraft_posts ) ) {
                    $autosave_autodraft_post = array_shift( $autosave_autodraft_posts );
                }
            }
        }

        $current_user_can_publish = current_user_can( get_post_type_object( 'customize_changeset' )->cap->publish_posts );

        // @todo Include all of the status labels here from script-loader.php, and then allow it to be filtered.
        $status_choices = array();
        if ( $current_user_can_publish ) {
            $status_choices[] = array(
                'status' => 'publish',
                'label' => __( 'Publish' ),
            );
        }
        $status_choices[] = array(
            'status' => 'draft',
            'label' => __( 'Save Draft' ),
        );
        if ( $current_user_can_publish ) {
            $status_choices[] = array(
                'status' => 'future',
                'label' => _x( 'Schedule', 'customizer changeset action/button label' ),
            );
        }

        // Prepare Customizer settings to pass to JavaScript.
        $changeset_post = null;
        if ( $changeset_post_id ) {
            $changeset_post = get_post( $changeset_post_id );
        }

        // Determine initial date to be at present or future, not past.
        $current_time = current_time( 'mysql', false );
        $initial_date = $current_time;
        if ( $changeset_post ) {
            $initial_date = get_the_time( 'Y-m-d H:i:s', $changeset_post->ID );
            if ( $initial_date < $current_time ) {
                $initial_date = $current_time;
            }
        }

        $lock_user_id = false;
        if ( $this->changeset_post_id() ) {
            $lock_user_id = wp_check_post_lock( $this->changeset_post_id() );
        }

        $settings = array(
            'changeset' => array(
                'uuid' => $this->changeset_uuid(),
                'branching' => $this->branching(),
                'autosaved' => $this->autosaved(),
                'hasAutosaveRevision' => ! empty( $autosave_revision_post ),
                'latestAutoDraftUuid' => $autosave_autodraft_post ? $autosave_autodraft_post->post_name : null,
                'status' => $changeset_post ? $changeset_post->post_status : '',
                'currentUserCanPublish' => $current_user_can_publish,
                'publishDate' => $initial_date,
                'statusChoices' => $status_choices,
                'lockUser' => $lock_user_id ? $this->get_lock_user_data( $lock_user_id ) : null,
            ),
            'initialServerDate' => $current_time,
            'dateFormat' => get_option( 'date_format' ),
            'timeFormat' => get_option( 'time_format' ),
            'initialServerTimestamp' => floor( microtime( true ) * 1000 ),
            'initialClientTimestamp' => -1, // To be set with JS below.
            'timeouts' => array(
                'windowRefresh' => 250,
                'changesetAutoSave' => AUTOSAVE_INTERVAL * 1000,
                'keepAliveCheck' => 2500,
                'reflowPaneContents' => 100,
                'previewFrameSensitivity' => 2000,
            ),
            'theme'    => array(
                'stylesheet'  => $this->get_stylesheet(),
                'active'      => $this->is_theme_active(),
                '_canInstall' => current_user_can( 'install_themes' ),
            ),
            'url'      => array(
                'preview'       => esc_url_raw( $this->get_preview_url() ),
                'return'        => esc_url_raw( $this->get_return_url() ),
                'parent'        => esc_url_raw( admin_url() ),
                'activated'     => esc_url_raw( home_url( '/' ) ),
                'ajax'          => esc_url_raw( admin_url( 'admin-ajax.php', 'relative' ) ),
                'allowed'       => array_map( 'esc_url_raw', $this->get_allowed_urls() ),
                'isCrossDomain' => $this->is_cross_domain(),
                'home'          => esc_url_raw( home_url( '/' ) ),
                'login'         => esc_url_raw( $login_url ),
            ),
            'browser'  => array(
                'mobile' => wp_is_mobile(),
                'ios'    => $this->is_ios(),
            ),
            'panels'   => array(),
            'sections' => array(),
            'nonce'    => $this->get_nonces(),
            'autofocus' => $this->get_autofocus(),
            'documentTitleTmpl' => $this->get_document_title_template(),
            'previewableDevices' => $this->get_previewable_devices(),
            'l10n' => array(
                'confirmDeleteTheme' => __( 'Are you sure you want to delete this theme?' ),
                /* translators: %d: number of theme search results, which cannot currently consider singular vs. plural forms */
                'themeSearchResults' => __( '%d themes found' ),
                /* translators: %d: number of themes being displayed, which cannot currently consider singular vs. plural forms */
                'announceThemeCount' => __( 'Displaying %d themes' ),
                /* translators: %s: theme name */
                'announceThemeDetails' => __( 'Showing details for theme: %s' ),
            ),
        );

        // Temporarily disable installation in Customizer. See #42184.
        $filesystem_method = get_filesystem_method();
        ob_start();
        $filesystem_credentials_are_stored = request_filesystem_credentials( self_admin_url() );
        ob_end_clean();
        if ( 'direct' !== $filesystem_method && ! $filesystem_credentials_are_stored ) {
            $settings['theme']['_filesystemCredentialsNeeded'] = true;
        }

        // Prepare Customize Section objects to pass to JavaScript.
        foreach ( $this->sections() as $id => $section ) {
            if ( $section->check_capabilities() ) {
                $settings['sections'][ $id ] = $section->json();
            }
        }

        // Prepare Customize Panel objects to pass to JavaScript.
        foreach ( $this->panels() as $panel_id => $panel ) {
            if ( $panel->check_capabilities() ) {
                $settings['panels'][ $panel_id ] = $panel->json();
                foreach ( $panel->sections as $section_id => $section ) {
                    if ( $section->check_capabilities() ) {
                        $settings['sections'][ $section_id ] = $section->json();
                    }
                }
            }
        }

        ?>
        <script type="text/javascript">
            var _wpCustomizeSettings = <?php echo wp_json_encode( $settings ); ?>;
            _wpCustomizeSettings.initialClientTimestamp = _.now();
            _wpCustomizeSettings.controls = {};
            _wpCustomizeSettings.settings = {};
            <?php

            // Serialize settings one by one to improve memory usage.
            echo "(function ( s ){\n";
            foreach ( $this->settings() as $setting ) {
                if ( $setting->check_capabilities() ) {
                    printf(
                        "s[%s] = %s;\n",
                        wp_json_encode( $setting->id ),
                        wp_json_encode( $setting->json() )
                    );
                }
            }
            echo "})( _wpCustomizeSettings.settings );\n";

            // Serialize controls one by one to improve memory usage.
            echo "(function ( c ){\n";
            foreach ( $this->controls() as $control ) {
                if ( $control->check_capabilities() ) {
                    printf(
                        "c[%s] = %s;\n",
                        wp_json_encode( $control->id ),
                        wp_json_encode( $control->json() )
                    );
                }
            }
            echo "})( _wpCustomizeSettings.controls );\n";
        ?>
        </script>
        <?php
    }

    /**
     * Returns a list of devices to allow previewing.
     *
     * @since 4.5.0
     *
     * @return array List of devices with labels and default setting.
     */
    public function get_previewable_devices() {
        $devices = array(
            'desktop' => array(
                'label' => __( 'Enter desktop preview mode' ),
                'default' => true,
            ),
            'tablet' => array(
                'label' => __( 'Enter tablet preview mode' ),
            ),
            'mobile' => array(
                'label' => __( 'Enter mobile preview mode' ),
            ),
        );

        /**
         * Filters the available devices to allow previewing in the Customizer.
         *
         * @since 4.5.0
         *
         * @see WP_Customize_Manager::get_previewable_devices()
         *
         * @param array $devices List of devices with labels and default setting.
         */
        $devices = apply_filters( 'customize_previewable_devices', $devices );

        return $devices;
    }

    /**
     * Register some default controls.
     *
     * @since 3.4.0
     */
    public function register_controls() {

        /* Themes (controls are loaded via ajax) */

        $this->add_panel( new WP_Customize_Themes_Panel( $this, 'themes', array(
            'title'       => $this->theme()->display( 'Name' ),
            'description' => (
                '<p>' . __( 'Looking for a theme? You can search or browse the WordPress.org theme directory, install and preview themes, then activate them right here.' ) . '</p>' .
                '<p>' . __( 'While previewing a new theme, you can continue to tailor things like widgets and menus, and explore theme-specific options.' ) . '</p>'
            ),
            'capability'  => 'switch_themes',
            'priority'    => 0,
        ) ) );

        $this->add_section( new WP_Customize_Themes_Section( $this, 'installed_themes', array(
            'title'       => __( 'Installed themes' ),
            'action'      => 'installed',
            'capability'  => 'switch_themes',
            'panel'       => 'themes',
            'priority'    => 0,
        ) ) );

        if ( ! is_multisite() ) {
            $this->add_section( new WP_Customize_Themes_Section( $this, 'wporg_themes', array(
                'title'       => __( 'WordPress.org themes' ),
                'action'      => 'wporg',
                'filter_type' => 'remote',
                'capability'  => 'install_themes',
                'panel'       => 'themes',
                'priority'    => 5,
            ) ) );
        }

        // Themes Setting (unused - the theme is considerably more fundamental to the Customizer experience).
        $this->add_setting( new WP_Customize_Filter_Setting( $this, 'active_theme', array(
            'capability' => 'switch_themes',
        ) ) );

        /* Site Identity */

        $this->add_section( 'title_tagline', array(
            'title'    => __( 'Site Identity' ),
            'priority' => 20,
        ) );

        $this->add_setting( 'blogname', array(
            'default'    => get_option( 'blogname' ),
            'type'       => 'option',
            'capability' => 'manage_options',
        ) );

        $this->add_control( 'blogname', array(
            'label'      => __( 'Site Title' ),
            'section'    => 'title_tagline',
        ) );

        $this->add_setting( 'blogdescription', array(
            'default'    => get_option( 'blogdescription' ),
            'type'       => 'option',
            'capability' => 'manage_options',
        ) );

        $this->add_control( 'blogdescription', array(
            'label'      => __( 'Tagline' ),
            'section'    => 'title_tagline',
        ) );

        // Add a setting to hide header text if the theme doesn't support custom headers.
        if ( ! current_theme_supports( 'custom-header', 'header-text' ) ) {
            $this->add_setting( 'header_text', array(
                'theme_supports'    => array( 'custom-logo', 'header-text' ),
                'default'           => 1,
                'sanitize_callback' => 'absint',
            ) );

            $this->add_control( 'header_text', array(
                'label'    => __( 'Display Site Title and Tagline' ),
                'section'  => 'title_tagline',
                'settings' => 'header_text',
                'type'     => 'checkbox',
            ) );
        }

        $this->add_setting( 'site_icon', array(
            'type'       => 'option',
            'capability' => 'manage_options',
            'transport'  => 'postMessage', // Previewed with JS in the Customizer controls window.
        ) );

        $this->add_control( new WP_Customize_Site_Icon_Control( $this, 'site_icon', array(
            'label'       => __( 'Site Icon' ),
            'description' => sprintf(
                '<p>' . __( 'Site Icons are what you see in browser tabs, bookmark bars, and within the WordPress mobile apps. Upload one here!' ) . '</p>' .
                /* translators: %s: site icon size in pixels */
                '<p>' . __( 'Site Icons should be square and at least %s pixels.' ) . '</p>',
                '<strong>512 × 512</strong>'
            ),
            'section'     => 'title_tagline',
            'priority'    => 60,
            'height'      => 512,
            'width'       => 512,
        ) ) );

        $this->add_setting( 'custom_logo', array(
            'theme_supports' => array( 'custom-logo' ),
            'transport'      => 'postMessage',
        ) );

        $custom_logo_args = get_theme_support( 'custom-logo' );
        $this->add_control( new WP_Customize_Cropped_Image_Control( $this, 'custom_logo', array(
            'label'         => __( 'Logo' ),
            'section'       => 'title_tagline',
            'priority'      => 8,
            'height'        => $custom_logo_args[0]['height'],
            'width'         => $custom_logo_args[0]['width'],
            'flex_height'   => $custom_logo_args[0]['flex-height'],
            'flex_width'    => $custom_logo_args[0]['flex-width'],
            'button_labels' => array(
                'select'       => __( 'Select logo' ),
                'change'       => __( 'Change logo' ),
                'remove'       => __( 'Remove' ),
                'default'      => __( 'Default' ),
                'placeholder'  => __( 'No logo selected' ),
                'frame_title'  => __( 'Select logo' ),
                'frame_button' => __( 'Choose logo' ),
            ),
        ) ) );

        $this->selective_refresh->add_partial( 'custom_logo', array(
            'settings'            => array( 'custom_logo' ),
            'selector'            => '.custom-logo-link',
            'render_callback'     => array( $this, '_render_custom_logo_partial' ),
            'container_inclusive' => true,
        ) );

        /* Colors */

        $this->add_section( 'colors', array(
            'title'          => __( 'Colors' ),
            'priority'       => 40,
        ) );

        $this->add_setting( 'header_textcolor', array(
            'theme_supports' => array( 'custom-header', 'header-text' ),
            'default'        => get_theme_support( 'custom-header', 'default-text-color' ),

            'sanitize_callback'    => array( $this, '_sanitize_header_textcolor' ),
            'sanitize_js_callback' => 'maybe_hash_hex_color',
        ) );

        // Input type: checkbox
        // With custom value
        $this->add_control( 'display_header_text', array(
            'settings' => 'header_textcolor',
            'label'    => __( 'Display Site Title and Tagline' ),
            'section'  => 'title_tagline',
            'type'     => 'checkbox',
            'priority' => 40,
        ) );

        $this->add_control( new WP_Customize_Color_Control( $this, 'header_textcolor', array(
            'label'   => __( 'Header Text Color' ),
            'section' => 'colors',
        ) ) );

        // Input type: Color
        // With sanitize_callback
        $this->add_setting( 'background_color', array(
            'default'        => get_theme_support( 'custom-background', 'default-color' ),
            'theme_supports' => 'custom-background',

            'sanitize_callback'    => 'sanitize_hex_color_no_hash',
            'sanitize_js_callback' => 'maybe_hash_hex_color',
        ) );

        $this->add_control( new WP_Customize_Color_Control( $this, 'background_color', array(
            'label'   => __( 'Background Color' ),
            'section' => 'colors',
        ) ) );

        /* Custom Header */

        if ( current_theme_supports( 'custom-header', 'video' ) ) {
            $title = __( 'Header Media' );
            $description = '<p>' . __( 'If you add a video, the image will be used as a fallback while the video loads.' ) . '</p>';

            $width = absint( get_theme_support( 'custom-header', 'width' ) );
            $height = absint( get_theme_support( 'custom-header', 'height' ) );
            if ( $width && $height ) {
                $control_description = sprintf(
                    /* translators: 1: .mp4, 2: header size in pixels */
                    __( 'Upload your video in %1$s format and minimize its file size for best results. Your theme recommends dimensions of %2$s pixels.' ),
                    '<code>.mp4</code>',
                    sprintf( '<strong>%s × %s</strong>', $width, $height )
                );
            } elseif ( $width ) {
                $control_description = sprintf(
                    /* translators: 1: .mp4, 2: header width in pixels */
                    __( 'Upload your video in %1$s format and minimize its file size for best results. Your theme recommends a width of %2$s pixels.' ),
                    '<code>.mp4</code>',
                    sprintf( '<strong>%s</strong>', $width )
                );
            } else {
                $control_description = sprintf(
                    /* translators: 1: .mp4, 2: header height in pixels */
                    __( 'Upload your video in %1$s format and minimize its file size for best results. Your theme recommends a height of %2$s pixels.' ),
                    '<code>.mp4</code>',
                    sprintf( '<strong>%s</strong>', $height )
                );
            }
        } else {
            $title = __( 'Header Image' );
            $description = '';
            $control_description = '';
        }

        $this->add_section( 'header_image', array(
            'title'          => $title,
            'description'    => $description,
            'theme_supports' => 'custom-header',
            'priority'       => 60,
        ) );

        $this->add_setting( 'header_video', array(
            'theme_supports'    => array( 'custom-header', 'video' ),
            'transport'         => 'postMessage',
            'sanitize_callback' => 'absint',
            'validate_callback' => array( $this, '_validate_header_video' ),
        ) );

        $this->add_setting( 'external_header_video', array(
            'theme_supports'    => array( 'custom-header', 'video' ),
            'transport'         => 'postMessage',
            'sanitize_callback' => array( $this, '_sanitize_external_header_video' ),
            'validate_callback' => array( $this, '_validate_external_header_video' ),
        ) );

        $this->add_setting( new WP_Customize_Filter_Setting( $this, 'header_image', array(
            'default'        => sprintf( get_theme_support( 'custom-header', 'default-image' ), get_template_directory_uri(), get_stylesheet_directory_uri() ),
            'theme_supports' => 'custom-header',
        ) ) );

        $this->add_setting( new WP_Customize_Header_Image_Setting( $this, 'header_image_data', array(
            'theme_supports' => 'custom-header',
        ) ) );

        /*
         * Switch image settings to postMessage when video support is enabled since
         * it entails that the_custom_header_markup() will be used, and thus selective
         * refresh can be utilized.
         */
        if ( current_theme_supports( 'custom-header', 'video' ) ) {
            $this->get_setting( 'header_image' )->transport = 'postMessage';
            $this->get_setting( 'header_image_data' )->transport = 'postMessage';
        }

        $this->add_control( new WP_Customize_Media_Control( $this, 'header_video', array(
            'theme_supports' => array( 'custom-header', 'video' ),
            'label'          => __( 'Header Video' ),
            'description'    => $control_description,
            'section'        => 'header_image',
            'mime_type'      => 'video',
            'active_callback' => 'is_header_video_active',
        ) ) );

        $this->add_control( 'external_header_video', array(
            'theme_supports' => array( 'custom-header', 'video' ),
            'type'           => 'url',
            'description'    => __( 'Or, enter a YouTube URL:' ),
            'section'        => 'header_image',
            'active_callback' => 'is_header_video_active',
        ) );

        $this->add_control( new WP_Customize_Header_Image_Control( $this ) );

        $this->selective_refresh->add_partial( 'custom_header', array(
            'selector'            => '#wp-custom-header',
            'render_callback'     => 'the_custom_header_markup',
            'settings'            => array( 'header_video', 'external_header_video', 'header_image' ), // The image is used as a video fallback here.
            'container_inclusive' => true,
        ) );

        /* Custom Background */

        $this->add_section( 'background_image', array(
            'title'          => __( 'Background Image' ),
            'theme_supports' => 'custom-background',
            'priority'       => 80,
        ) );

        $this->add_setting( 'background_image', array(
            'default'        => get_theme_support( 'custom-background', 'default-image' ),
            'theme_supports' => 'custom-background',
            'sanitize_callback' => array( $this, '_sanitize_background_setting' ),
        ) );

        $this->add_setting( new WP_Customize_Background_Image_Setting( $this, 'background_image_thumb', array(
            'theme_supports' => 'custom-background',
            'sanitize_callback' => array( $this, '_sanitize_background_setting' ),
        ) ) );

        $this->add_control( new WP_Customize_Background_Image_Control( $this ) );

        $this->add_setting( 'background_preset', array(
            'default'        => get_theme_support( 'custom-background', 'default-preset' ),
            'theme_supports' => 'custom-background',
            'sanitize_callback' => array( $this, '_sanitize_background_setting' ),
        ) );

        $this->add_control( 'background_preset', array(
            'label'      => _x( 'Preset', 'Background Preset' ),
            'section'    => 'background_image',
            'type'       => 'select',
            'choices'    => array(
                'default' => _x( 'Default', 'Default Preset' ),
                'fill'    => __( 'Fill Screen' ),
                'fit'     => __( 'Fit to Screen' ),
                'repeat'  => _x( 'Repeat', 'Repeat Image' ),
                'custom'  => _x( 'Custom', 'Custom Preset' ),
            ),
        ) );

        $this->add_setting( 'background_position_x', array(
            'default'        => get_theme_support( 'custom-background', 'default-position-x' ),
            'theme_supports' => 'custom-background',
            'sanitize_callback' => array( $this, '_sanitize_background_setting' ),
        ) );

        $this->add_setting( 'background_position_y', array(
            'default'        => get_theme_support( 'custom-background', 'default-position-y' ),
            'theme_supports' => 'custom-background',
            'sanitize_callback' => array( $this, '_sanitize_background_setting' ),
        ) );

        $this->add_control( new WP_Customize_Background_Position_Control( $this, 'background_position', array(
            'label'    => __( 'Image Position' ),
            'section'  => 'background_image',
            'settings' => array(
                'x' => 'background_position_x',
                'y' => 'background_position_y',
            ),
        ) ) );

        $this->add_setting( 'background_size', array(
            'default'        => get_theme_support( 'custom-background', 'default-size' ),
            'theme_supports' => 'custom-background',
            'sanitize_callback' => array( $this, '_sanitize_background_setting' ),
        ) );

        $this->add_control( 'background_size', array(
            'label'      => __( 'Image Size' ),
            'section'    => 'background_image',
            'type'       => 'select',
            'choices'    => array(
                'auto'    => __( 'Original' ),
                'contain' => __( 'Fit to Screen' ),
                'cover'   => __( 'Fill Screen' ),
            ),
        ) );

        $this->add_setting( 'background_repeat', array(
            'default'           => get_theme_support( 'custom-background', 'default-repeat' ),
            'sanitize_callback' => array( $this, '_sanitize_background_setting' ),
            'theme_supports'    => 'custom-background',
        ) );

        $this->add_control( 'background_repeat', array(
            'label'    => __( 'Repeat Background Image' ),
            'section'  => 'background_image',
            'type'     => 'checkbox',
        ) );

        $this->add_setting( 'background_attachment', array(
            'default'           => get_theme_support( 'custom-background', 'default-attachment' ),
            'sanitize_callback' => array( $this, '_sanitize_background_setting' ),
            'theme_supports'    => 'custom-background',
        ) );

        $this->add_control( 'background_attachment', array(
            'label'    => __( 'Scroll with Page' ),
            'section'  => 'background_image',
            'type'     => 'checkbox',
        ) );


        // If the theme is using the default background callback, we can update
        // the background CSS using postMessage.
        if ( get_theme_support( 'custom-background', 'wp-head-callback' ) === '_custom_background_cb' ) {
            foreach ( array( 'color', 'image', 'preset', 'position_x', 'position_y', 'size', 'repeat', 'attachment' ) as $prop ) {
                $this->get_setting( 'background_' . $prop )->transport = 'postMessage';
            }
        }

        /*
         * Static Front Page
         * See also https://core.trac.wordpress.org/ticket/19627 which introduces the static-front-page theme_support.
         * The following replicates behavior from options-reading.php.
         */

        $this->add_section( 'static_front_page', array(
            'title' => __( 'Homepage Settings' ),
            'priority' => 120,
            'description' => __( 'You can choose what’s displayed on the homepage of your site. It can be posts in reverse chronological order (classic blog), or a fixed/static page. To set a static homepage, you first need to create two Pages. One will become the homepage, and the other will be where your posts are displayed.' ),
            'active_callback' => array( $this, 'has_published_pages' ),
        ) );

        $this->add_setting( 'show_on_front', array(
            'default' => get_option( 'show_on_front' ),
            'capability' => 'manage_options',
            'type' => 'option',
        ) );

        $this->add_control( 'show_on_front', array(
            'label' => __( 'Your homepage displays' ),
            'section' => 'static_front_page',
            'type' => 'radio',
            'choices' => array(
                'posts' => __( 'Your latest posts' ),
                'page'  => __( 'A static page' ),
            ),
        ) );

        $this->add_setting( 'page_on_front', array(
            'type'       => 'option',
            'capability' => 'manage_options',
        ) );

        $this->add_control( 'page_on_front', array(
            'label' => __( 'Homepage' ),
            'section' => 'static_front_page',
            'type' => 'dropdown-pages',
            'allow_addition' => true,
        ) );

        $this->add_setting( 'page_for_posts', array(
            'type' => 'option',
            'capability' => 'manage_options',
        ) );

        $this->add_control( 'page_for_posts', array(
            'label' => __( 'Posts page' ),
            'section' => 'static_front_page',
            'type' => 'dropdown-pages',
            'allow_addition' => true,
        ) );

        /* Custom CSS */
        $section_description = '<p>';
        $section_description .= __( 'Add your own CSS code here to customize the appearance and layout of your site.' );
        $section_description .= sprintf(
            ' <a href="%1$s" class="external-link" target="_blank">%2$s<span class="screen-reader-text"> %3$s</span></a>',
            esc_url( __( 'https://codex.wordpress.org/CSS' ) ),
            __( 'Learn more about CSS' ),
            /* translators: accessibility text */
            __( '(opens in a new window)' )
        );
        $section_description .= '</p>';

        $section_description .= '<p id="editor-keyboard-trap-help-1">' . __( 'When using a keyboard to navigate:' ) . '</p>';
        $section_description .= '<ul>';
        $section_description .= '<li id="editor-keyboard-trap-help-2">' . __( 'In the editing area, the Tab key enters a tab character.' ) . '</li>';
        $section_description .= '<li id="editor-keyboard-trap-help-3">' . __( 'To move away from this area, press the Esc key followed by the Tab key.' ) . '</li>';
        $section_description .= '<li id="editor-keyboard-trap-help-4">' . __( 'Screen reader users: when in forms mode, you may need to press the escape key twice.' ) . '</li>';
        $section_description .= '</ul>';

        if ( 'false' !== wp_get_current_user()->syntax_highlighting ) {
            $section_description .= '<p>';
            $section_description .= sprintf(
                /* translators: 1: link to user profile, 2: additional link attributes, 3: accessibility text */
                __( 'The edit field automatically highlights code syntax. You can disable this in your <a href="%1$s" %2$s>user profile%3$s</a> to work in plain text mode.' ),
                esc_url( get_edit_profile_url() ),
                'class="external-link" target="_blank"',
                sprintf( '<span class="screen-reader-text"> %s</span>',
                    /* translators: accessibility text */
                    __( '(opens in a new window)' )
                )
            );
            $section_description .= '</p>';
        }

        $section_description .= '<p class="section-description-buttons">';
        $section_description .= '<button type="button" class="button-link section-description-close">' . __( 'Close' ) . '</button>';
        $section_description .= '</p>';

        $this->add_section( 'custom_css', array(
            'title'              => __( 'Additional CSS' ),
            'priority'           => 200,
            'description_hidden' => true,
            'description'        => $section_description,
        ) );

        $custom_css_setting = new WP_Customize_Custom_CSS_Setting( $this, sprintf( 'custom_css[%s]', get_stylesheet() ), array(
            'capability' => 'edit_css',
            'default' => '',
        ) );
        $this->add_setting( $custom_css_setting );

        $this->add_control( new WP_Customize_Code_Editor_Control( $this, 'custom_css', array(
            'label'       => __( 'CSS code' ),
            'section'     => 'custom_css',
            'settings'    => array( 'default' => $custom_css_setting->id ),
            'code_type'   => 'text/css',
            'input_attrs' => array(
                'aria-describedby' => 'editor-keyboard-trap-help-1 editor-keyboard-trap-help-2 editor-keyboard-trap-help-3 editor-keyboard-trap-help-4',
            ),
        ) ) );
    }

    /**
     * Return whether there are published pages.
     *
     * Used as active callback for static front page section and controls.
     *
     * @since 4.7.0
     *
     * @returns bool Whether there are published (or to be published) pages.
     */
    public function has_published_pages() {

        $setting = $this->get_setting( 'nav_menus_created_posts' );
        if ( $setting ) {
            foreach ( $setting->value() as $post_id ) {
                if ( 'page' === get_post_type( $post_id ) ) {
                    return true;
                }
            }
        }
        return 0 !== count( get_pages() );
    }

    /**
     * Add settings from the POST data that were not added with code, e.g. dynamically-created settings for Widgets
     *
     * @since 4.2.0
     *
     * @see add_dynamic_settings()
     */
    public function register_dynamic_settings() {
        $setting_ids = array_keys( $this->unsanitized_post_values() );
        $this->add_dynamic_settings( $setting_ids );
    }

    /**
     * Load themes into the theme browsing/installation UI.
     *
     * @since 4.9.0
     */
    public function handle_load_themes_request() {
        check_ajax_referer( 'switch_themes', 'nonce' );

        if ( ! current_user_can( 'switch_themes' ) ) {
            wp_die( -1 );
        }

        if ( empty( $_POST['theme_action'] ) ) {
            wp_send_json_error( 'missing_theme_action' );
        }
        $theme_action = sanitize_key( $_POST['theme_action'] );
        $themes = array();
        $args = array();

        // Define query filters based on user input.
        if ( ! array_key_exists( 'search', $_POST ) ) {
            $args['search'] = '';
        } else {
            $args['search'] = sanitize_text_field( wp_unslash( $_POST['search'] ) );
        }

        if ( ! array_key_exists( 'tags', $_POST ) ) {
            $args['tag'] = '';
        } else {
            $args['tag'] = array_map( 'sanitize_text_field', wp_unslash( (array) $_POST['tags'] ) );
        }

        if ( ! array_key_exists( 'page', $_POST ) ) {
            $args['page'] = 1;
        } else {
            $args['page'] = absint( $_POST['page'] );
        }

        require_once ABSPATH . 'wp-admin/includes/theme.php';

        if ( 'installed' === $theme_action ) {

            // Load all installed themes from wp_prepare_themes_for_js().
            $themes = array( 'themes' => wp_prepare_themes_for_js() );
            foreach ( $themes['themes'] as &$theme ) {
                $theme['type'] = 'installed';
                $theme['active'] = ( isset( $_POST['customized_theme'] ) && $_POST['customized_theme'] === $theme['id'] );
            }

        } elseif ( 'wporg' === $theme_action ) {

            // Load WordPress.org themes from the .org API and normalize data to match installed theme objects.
            if ( ! current_user_can( 'install_themes' ) ) {
                wp_die( -1 );
            }

            // Arguments for all queries.
            $wporg_args = array(
                'per_page' => 100,
                'fields' => array(
                    'screenshot_url' => true,
                    'description' => true,
                    'rating' => true,
                    'downloaded' => true,
                    'downloadlink' => true,
                    'last_updated' => true,
                    'homepage' => true,
                    'num_ratings' => true,
                    'tags' => true,
                    'parent' => true,
                    // 'extended_author' => true, @todo: WordPress.org throws a 500 server error when this is here.
                ),
            );

            $args = array_merge( $wporg_args, $args );

            if ( '' === $args['search'] && '' === $args['tag'] ) {
                $args['browse'] = 'new'; // Sort by latest themes by default.
            }

            // Load themes from the .org API.
            $themes = themes_api( 'query_themes', $args );
            if ( is_wp_error( $themes ) ) {
                wp_send_json_error();
            }

            // This list matches the allowed tags in wp-admin/includes/theme-install.php.
            $themes_allowedtags = array_fill_keys(
                array( 'a', 'abbr', 'acronym', 'code', 'pre', 'em', 'strong', 'div', 'p', 'ul', 'ol', 'li', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'img' ),
                array()
            );
            $themes_allowedtags['a'] = array_fill_keys( array( 'href', 'title', 'target' ), true );
            $themes_allowedtags['acronym']['title'] = true;
            $themes_allowedtags['abbr']['title'] = true;
            $themes_allowedtags['img'] = array_fill_keys( array( 'src', 'class', 'alt' ), true );

            // Prepare a list of installed themes to check against before the loop.
            $installed_themes = array();
            $wp_themes = wp_get_themes();
            foreach ( $wp_themes as $theme ) {
                $installed_themes[] = $theme->get_stylesheet();
            }
            $update_php = network_admin_url( 'update.php?action=install-theme' );

            // Set up properties for themes available on WordPress.org.
            foreach ( $themes->themes as &$theme ) {
                $theme->install_url = add_query_arg( array(
                    'theme'    => $theme->slug,
                    '_wpnonce' => wp_create_nonce( 'install-theme_' . $theme->slug ),
                ), $update_php );

                $theme->name        = wp_kses( $theme->name, $themes_allowedtags );
                $theme->author      = wp_kses( $theme->author, $themes_allowedtags );
                $theme->version     = wp_kses( $theme->version, $themes_allowedtags );
                $theme->description = wp_kses( $theme->description, $themes_allowedtags );
                $theme->tags        = implode( ', ', $theme->tags );
                $theme->stars       = wp_star_rating( array(
                    'rating' => $theme->rating,
                    'type' => 'percent',
                    'number' => $theme->num_ratings,
                    'echo' => false,
                ) );
                $theme->num_ratings = number_format_i18n( $theme->num_ratings );
                $theme->preview_url = set_url_scheme( $theme->preview_url );

                // Handle themes that are already installed as installed themes.
                if ( in_array( $theme->slug, $installed_themes, true ) ) {
                    $theme->type = 'installed';
                } else {
                    $theme->type = $theme_action;
                }

                // Set active based on customized theme.
                $theme->active = ( isset( $_POST['customized_theme'] ) && $_POST['customized_theme'] === $theme->slug );

                // Map available theme properties to installed theme properties.
                $theme->id           = $theme->slug;
                $theme->screenshot   = array( $theme->screenshot_url );
                $theme->authorAndUri = $theme->author;
                // The .org API can return the full parent theme details if passed the 'parent' arg, or if passed the 'template' option it'll return that in the event it's a child theme.
                if ( isset( $theme->parent ) ) {
                    $theme->parent = $theme->parent['slug'];
                } else {
                    $theme->parent = false;
                }
                unset( $theme->slug );
                unset( $theme->screenshot_url );
                unset( $theme->author );
            } // End foreach().
        } // End if().

        /**
         * Filters the theme data loaded in the customizer.
         *
         * This allows theme data to be loading from an external source,
         * or modification of data loaded from `wp_prepare_themes_for_js()`
         * or WordPress.org via `themes_api()`.
         *
         * @since 4.9.0
         *
         * @see wp_prepare_themes_for_js()
         * @see themes_api()
         * @see WP_Customize_Manager::__construct()
         *
         * @param array                $themes  Nested array of theme data.
         * @param array                $args    List of arguments, such as page, search term, and tags to query for.
         * @param WP_Customize_Manager $manager Instance of Customize manager.
         */
        $themes = apply_filters( 'customize_load_themes', $themes, $args, $this );

        wp_send_json_success( $themes );
    }


    /**
     * Callback for validating the header_textcolor value.
     *
     * Accepts 'blank', and otherwise uses sanitize_hex_color_no_hash().
     * Returns default text color if hex color is empty.
     *
     * @since 3.4.0
     *
     * @param string $color
     * @return mixed
     */
    public function _sanitize_header_textcolor( $color ) {
        if ( 'blank' === $color )
            return 'blank';

        $color = sanitize_hex_color_no_hash( $color );
        if ( empty( $color ) )
            $color = get_theme_support( 'custom-header', 'default-text-color' );

        return $color;
    }

    /**
     * Callback for validating a background setting value.
     *
     * @since 4.7.0
     *
     * @param string $value Repeat value.
     * @param WP_Customize_Setting $setting Setting.
     * @return string|WP_Error Background value or validation error.
     */
    public function _sanitize_background_setting( $value, $setting ) {
        if ( 'background_repeat' === $setting->id ) {
            if ( ! in_array( $value, array( 'repeat-x', 'repeat-y', 'repeat', 'no-repeat' ) ) ) {
                return new WP_Error( 'invalid_value', __( 'Invalid value for background repeat.' ) );
            }
        } elseif ( 'background_attachment' === $setting->id ) {
            if ( ! in_array( $value, array( 'fixed', 'scroll' ) ) ) {
                return new WP_Error( 'invalid_value', __( 'Invalid value for background attachment.' ) );
            }
        } elseif ( 'background_position_x' === $setting->id ) {
            if ( ! in_array( $value, array( 'left', 'center', 'right' ), true ) ) {
                return new WP_Error( 'invalid_value', __( 'Invalid value for background position X.' ) );
            }
        } elseif ( 'background_position_y' === $setting->id ) {
            if ( ! in_array( $value, array( 'top', 'center', 'bottom' ), true ) ) {
                return new WP_Error( 'invalid_value', __( 'Invalid value for background position Y.' ) );
            }
        } elseif ( 'background_size' === $setting->id ) {
            if ( ! in_array( $value, array( 'auto', 'contain', 'cover' ), true ) ) {
                return new WP_Error( 'invalid_value', __( 'Invalid value for background size.' ) );
            }
        } elseif ( 'background_preset' === $setting->id ) {
            if ( ! in_array( $value, array( 'default', 'fill', 'fit', 'repeat', 'custom' ), true ) ) {
                return new WP_Error( 'invalid_value', __( 'Invalid value for background size.' ) );
            }
        } elseif ( 'background_image' === $setting->id || 'background_image_thumb' === $setting->id ) {
            $value = empty( $value ) ? '' : esc_url_raw( $value );
        } else {
            return new WP_Error( 'unrecognized_setting', __( 'Unrecognized background setting.' ) );
        }
        return $value;
    }

    /**
     * Export header video settings to facilitate selective refresh.
     *
     * @since 4.7.0
     *
     * @param array $response Response.
     * @param WP_Customize_Selective_Refresh $selective_refresh Selective refresh component.
     * @param array $partials Array of partials.
     * @return array
     */
    public function export_header_video_settings( $response, $selective_refresh, $partials ) {
        if ( isset( $partials['custom_header'] ) ) {
            $response['custom_header_settings'] = get_header_video_settings();
        }

        return $response;
    }

    /**
     * Callback for validating the header_video value.
     *
     * Ensures that the selected video is less than 8MB and provides an error message.
     *
     * @since 4.7.0
     *
     * @param WP_Error $validity
     * @param mixed $value
     * @return mixed
     */
    public function _validate_header_video( $validity, $value ) {
        $video = get_attached_file( absint( $value ) );
        if ( $video ) {
            $size = filesize( $video );
            if ( 8 < $size / pow( 1024, 2 ) ) { // Check whether the size is larger than 8MB.
                $validity->add( 'size_too_large',
                    __( 'This video file is too large to use as a header video. Try a shorter video or optimize the compression settings and re-upload a file that is less than 8MB. Or, upload your video to YouTube and link it with the option below.' )
                );
            }
            if ( '.mp4' !== substr( $video, -4 ) && '.mov' !== substr( $video, -4 ) ) { // Check for .mp4 or .mov format, which (assuming h.264 encoding) are the only cross-browser-supported formats.
                $validity->add( 'invalid_file_type', sprintf(
                    /* translators: 1: .mp4, 2: .mov */
                    __( 'Only %1$s or %2$s files may be used for header video. Please convert your video file and try again, or, upload your video to YouTube and link it with the option below.' ),
                    '<code>.mp4</code>',
                    '<code>.mov</code>'
                ) );
            }
        }
        return $validity;
    }

    /**
     * Callback for validating the external_header_video value.
     *
     * Ensures that the provided URL is supported.
     *
     * @since 4.7.0
     *
     * @param WP_Error $validity
     * @param mixed $value
     * @return mixed
     */
    public function _validate_external_header_video( $validity, $value ) {
        $video = esc_url_raw( $value );
        if ( $video ) {
            if ( ! preg_match( '#^https?://(?:www\.)?(?:youtube\.com/watch|youtu\.be/)#', $video ) ) {
                $validity->add( 'invalid_url', __( 'Please enter a valid YouTube URL.' ) );
            }
        }
        return $validity;
    }

    /**
     * Callback for sanitizing the external_header_video value.
     *
     * @since 4.7.1
     *
     * @param string $value URL.
     * @return string Sanitized URL.
     */
    public function _sanitize_external_header_video( $value ) {
        return esc_url_raw( trim( $value ) );
    }

    /**
     * Callback for rendering the custom logo, used in the custom_logo partial.
     *
     * This method exists because the partial object and context data are passed
     * into a partial's render_callback so we cannot use get_custom_logo() as
     * the render_callback directly since it expects a blog ID as the first
     * argument. When WP no longer supports PHP 5.3, this method can be removed
     * in favor of an anonymous function.
     *
     * @see WP_Customize_Manager::register_controls()
     *
     * @since 4.5.0
     *
     * @return string Custom logo.
     */
    public function _render_custom_logo_partial() {
        return get_custom_logo();
    }
}