static function getFirst( $return_post_id = false, $admin_mode = false ) {

		global $blog_id;

		$book_structure = static::getBookStructure();
		$order = $book_structure['__order'];
		$pos = array_keys( $order );

		reset( $pos );
		while ( $first_id = current( $pos ) ) {
			if ( $admin_mode ) {
				if ( current_user_can( 'edit_post', $first_id ) ) {
					break;
				} else {
					next( $pos );
				}
			} else {
				if ( in_array( $order[ $first_id ]['post_status'], [ 'publish', 'web-only' ], true ) ) {
					break;
				} elseif ( current_user_can_for_blog( $blog_id, 'read_private_posts' ) ) {
					break;
				} elseif ( get_option( 'permissive_private_content' ) && current_user_can_for_blog( $blog_id, 'read' ) ) {
					break;
				} else {
					next( $pos );
				}
			}
		}

		if ( $return_post_id ) {
			return (int) $first_id;
		} else {
			return ( empty( $first_id ) ) ? '/' : get_permalink( $first_id );
		}

	}