<?php
/**
 * Widget API: WP_Widget_Pages class
 *
 * @package WordPress
 * @subpackage Widgets
 * @since 4.4.0
 */

/**
 * Core class used to implement a Pages widget.
 *
 * @since 2.8.0
 *
 * @see WP_Widget
 */
class WP_Widget_Pages extends WP_Widget {

    /**
     * Sets up a new Pages widget instance.
     *
     * @since 2.8.0
     */
    public function __construct() {
        $widget_ops = array(
            'classname'                   => 'widget_pages',
            'description'                 => __( 'A list of your site&#8217;s Pages.' ),
            'customize_selective_refresh' => true,
            'show_instance_in_rest'       => true,
        );
        parent::__construct( 'pages', __( 'Pages' ), $widget_ops );
    }

    /**
     * Outputs the content for the current Pages widget instance.
     *
     * @since 2.8.0
     *
     * @param array $args     Display arguments including 'before_title', 'after_title',
     *                        'before_widget', and 'after_widget'.
     * @param array $instance Settings for the current Pages widget instance.
     */
    public function widget( $args, $instance ) {
        $default_title = __( 'Pages' );
        $title         = ! empty( $instance['title'] ) ? $instance['title'] : $default_title;

        /**
         * Filters the widget title.
         *
         * @since 2.6.0
         *
         * @param string $title    The widget title. Default 'Pages'.
         * @param array  $instance Array of settings for the current widget.
         * @param mixed  $id_base  The widget ID.
         */
        $title = apply_filters( 'widget_title', $title, $instance, $this->id_base );

        $sortby  = empty( $instance['sortby'] ) ? 'menu_order' : $instance['sortby'];
        $exclude = empty( $instance['exclude'] ) ? '' : $instance['exclude'];

        if ( 'menu_order' === $sortby ) {
            $sortby = 'menu_order, post_title';
        }

        $output = wp_list_pages(
            /**
             * Filters the arguments for the Pages widget.
             *
             * @since 2.8.0
             * @since 4.9.0 Added the `$instance` parameter.
             *
             * @see wp_list_pages()
             *
             * @param array $args     An array of arguments to retrieve the pages list.
             * @param array $instance Array of settings for the current widget.
             */
            apply_filters(
                'widget_pages_args',
                array(
                    'title_li'    => '',
                    'echo'        => 0,
                    'sort_column' => $sortby,
                    'exclude'     => $exclude,
                ),
                $instance
            )
        );

        if ( ! empty( $output ) ) {
            echo $args['before_widget'];
            if ( $title ) {
                echo $args['before_title'] . $title . $args['after_title'];
            }

            $format = current_theme_supports( 'html5', 'navigation-widgets' ) ? 'html5' : 'xhtml';

            /** This filter is documented in wp-includes/widgets/class-wp-nav-menu-widget.php */
            $format = apply_filters( 'navigation_widgets_format', $format );

            if ( 'html5' === $format ) {
                // The title may be filtered: Strip out HTML and make sure the aria-label is never empty.
                $title      = trim( strip_tags( $title ) );
                $aria_label = $title ? $title : $default_title;
                echo '<nav aria-label="' . esc_attr( $aria_label ) . '">';
            }
            ?>

            <ul>
                <?php echo $output; ?>
            </ul>

            <?php
            if ( 'html5' === $format ) {
                echo '</nav>';
            }

            echo $args['after_widget'];
        }
    }

    /**
     * Handles updating settings for the current Pages widget instance.
     *
     * @since 2.8.0
     *
     * @param array $new_instance New settings for this instance as input by the user via
     *                            WP_Widget::form().
     * @param array $old_instance Old settings for this instance.
     * @return array Updated settings to save.
     */
    public function update( $new_instance, $old_instance ) {
        $instance          = $old_instance;
        $instance['title'] = sanitize_text_field( $new_instance['title'] );
        if ( in_array( $new_instance['sortby'], array( 'post_title', 'menu_order', 'ID' ), true ) ) {
            $instance['sortby'] = $new_instance['sortby'];
        } else {
            $instance['sortby'] = 'menu_order';
        }

        $instance['exclude'] = sanitize_text_field( $new_instance['exclude'] );

        return $instance;
    }

    /**
     * Outputs the settings form for the Pages widget.
     *
     * @since 2.8.0
     *
     * @param array $instance Current settings.
     */
    public function form( $instance ) {
        // Defaults.
        $instance = wp_parse_args(
            (array) $instance,
            array(
                'sortby'  => 'post_title',
                'title'   => '',
                'exclude' => '',
            )
        );
        ?>
        <p>
            <label for="<?php echo esc_attr( $this->get_field_id( 'title' ) ); ?>"><?php _e( 'Title:' ); ?></label>
            <input class="widefat" id="<?php echo esc_attr( $this->get_field_id( 'title' ) ); ?>" name="<?php echo esc_attr( $this->get_field_name( 'title' ) ); ?>" type="text" value="<?php echo esc_attr( $instance['title'] ); ?>" />
        </p>

        <p>
            <label for="<?php echo esc_attr( $this->get_field_id( 'sortby' ) ); ?>"><?php _e( 'Sort by:' ); ?></label>
            <select name="<?php echo esc_attr( $this->get_field_name( 'sortby' ) ); ?>" id="<?php echo esc_attr( $this->get_field_id( 'sortby' ) ); ?>" class="widefat">
                <option value="post_title"<?php selected( $instance['sortby'], 'post_title' ); ?>><?php _e( 'Page title' ); ?></option>
                <option value="menu_order"<?php selected( $instance['sortby'], 'menu_order' ); ?>><?php _e( 'Page order' ); ?></option>
                <option value="ID"<?php selected( $instance['sortby'], 'ID' ); ?>><?php _e( 'Page ID' ); ?></option>
            </select>
        </p>

        <p>
            <label for="<?php echo esc_attr( $this->get_field_id( 'exclude' ) ); ?>"><?php _e( 'Exclude:' ); ?></label>
            <input type="text" value="<?php echo esc_attr( $instance['exclude'] ); ?>" name="<?php echo esc_attr( $this->get_field_name( 'exclude' ) ); ?>" id="<?php echo esc_attr( $this->get_field_id( 'exclude' ) ); ?>" class="widefat" />
            <br />
            <small><?php _e( 'Page IDs, separated by commas.' ); ?></small>
        </p>
        <?php
    }
}