[WordPress] meta box の位置を制御する

下北沢 OSS Cafe 確認スペシャルの補足
スケルトンだから、このままだと動かないよ。

<?php
new pan_pan_pan();

Class pan_pan_pan {
    private $field_name = array(
        'theme'   => 'pan_pan_pan_theme',
        'content' => 'pan_pan_pan_content',
    );
    CONST POST_TYPE  = 'pan_pan_pan';

    function __construct() {
        add_action( 'in_admin_header', array(&$this, 'in_admin_header') );
    }

    private function is_pan_pan_pan() {
        global $post_type;
        if ( isset($post_type) && $post_type === self::POST_TYPE )
            return TRUE;
        else if ( isset($_GET['post_type']) && $_GET['post_type'] === self::POST_TYPE )
            return TRUE;
        else
            return FALSE;
    }

    public function in_admin_header() {
        global $post_type, $current_user;

        if ( !$this->is_pan_pan_pan() )
            return;

        // 画面のカラム数の制御
        $screen_layout_columns = get_user_option("screen_layout_$post_type");
        if ( !$screen_layout_columns || $screen_layout_columns > 1 ) {
            update_user_option($current_user->ID, "screen_layout_$post_type", 1);
        }

        // メタボックスの表示位置の制御
        $meta_box_order_default = array(
            'side'     => '' ,
            'normal'   => "slugdiv,{$this->field_name['theme']},{$this->field_name['content']}",
            'advanced' => "submitdiv",
        );
        $meta_box_order = $meta_box_order_new = get_user_option("meta-box-order_$post_type");
        if ( $meta_box_order ) {
            // サイド
            $side = isset($meta_box_order['side'])
                ? explode(',', $meta_box_order['side'])
                : array();
            $meta_box_order_new['side'] = '';

            // ノーマル
            $normal = array_merge(
                explode(',', isset($meta_box_order['normal']) ? $meta_box_order['normal'] : $meta_box_order_default['normal']) ,
                $side
            );
            if ( !in_array($this->field_name['theme'], $normal) )
                $normal[] = $this->field_name['theme'];
            if ( !in_array($this->field_name['content'], $normal) )
                $normal[] = $this->field_name['content'];
            $meta_box_order_new['normal'] = implode(',', $normal);

            // advanced (サブミットボックスとか置いてある)
            $advanced = explode(',', isset($meta_box_order['advanced'])
                ? $meta_box_order['advanced']
                : $meta_box_order_default['advanced']);
            if ( !in_array('submitdiv', $advanced) )
                $advanced[] = 'submitdiv';
            $meta_box_order_new['advanced'] = implode(',', $advanced);
        } else {
            $meta_box_order_new = $meta_box_order_default;
        }
        if ( $meta_box_order !== $meta_box_order_new )
            update_user_option($current_user->ID, "meta-box-order_$post_type", $meta_box_order_new);

        // 隠したいメタボックスの制御
        $metaboxhidden = $metaboxhidden_new = (array)get_user_option("metaboxhidden_$post_type");
        if ( $metaboxhidden ) {
            if ( !in_array('categorydiv', $metaboxhidden) )
                $metaboxhidden_new[] = 'categorydiv';
            if ( !in_array('slugdiv', $metaboxhidden) )
                $metaboxhidden_new[] = 'slugdiv';
            if ( !in_array('commentstatusdiv', $metaboxhidden) )
                $metaboxhidden_new[] = 'commentstatusdiv';
        } else {
            $metaboxhidden_new = array('categorydiv','slugdiv','commentstatusdiv');
        }
        if ( $metaboxhidden !== $metaboxhidden_new )
            update_user_option($current_user->ID, "metaboxhidden_$post_type", $metaboxhidden_new);

        // 画面のカラム数の最大値を指定
        add_screen_option('layout_columns', array('max' => 1) );
    }
}