Wordpress Childs in sidebar

sidebar-page-childs.php

<?php

/*
 * get_page_depth
 * Gets the page depth, calls get_post on every iteration
 * https://gist.github.com/1039575
 */
if ( !function_exists( 'get_page_depth' ) ) {
	function get_page_depth( $id=0, $depth=0 ) {
		global $post;

		if ( $id == 0 ) 
			$id = $post->ID;

		$page = get_post( $id );
		if ( !$page->post_parent ) {
				// this page does not have any parent
				return $depth;
		}
		return get_page_depth( $page->post_parent, $depth+1 );
	}
}

if ( !function_exists( 'has_children' ) ) {
	function has_children() {
	  global $post;

	  $pages = get_pages('child_of=' . $post->ID);
		
	  if (count($pages) > 0):
		return true;
	  else:
		return false;
	  endif;
	}
}

if ( !function_exists( 'is_top_level' ) ) {
	function is_top_level() {
	  global $post, $wpdb;

	  $current_page = $wpdb->get_var("SELECT post_parent FROM $wpdb->posts WHERE ID = " . $post->ID);
		
	  if ($current_page == 0):
		return true;
	  else:
		return false;
	  endif;
		
	}
}

if ( !function_exists( 'get_page_siblings' ) ) {
	function get_page_siblings() { 

		global $post;
		$parents = get_post_ancestors( $post->ID );
		$page_depth = get_page_depth( $post->ID );
		$output = "";

		$target_page_id = $page_depth >= 1 ? $post->post_parent : $post->ID;
		$target_page = get_post( $target_page_id );

		//if page has children show
		if( is_top_level() && !has_children() ){

			return $output;

		} else {

			$output .= '<div class="barra-lateral-superior">';
			$output .= '<h2>'.$target_page->post_title.'</h2>';
			$output .= '<ul>';

			if ($page_depth != 0){
				//si estoy en una categoria menor que la maxima padre, muestro todo el arbol descendiente
				$output .= wp_list_pages("title_li=&child_of={$target_page_id}&depth=0&echo=0&sort_column=menu_order");

			} else {
				//si estoy en la categoria padre de padres, no mostrar tanta profundidad de hijos, nivel 2 esta ok
				$output .= wp_list_pages("title_li=&child_of={$target_page_id}&depth=2&echo=0&sort_column=menu_order");
			}

			$output .= '</ul>';
			$output .= '</div>';
		}

		return $output;

	}
}

add_shortcode('charrua_sidebar_childs', 'get_page_siblings');