hierachical category listing, process_cat_tree() function

/************************************************************************
* a function to recursively build a hierachical category listing;
* alchymyth 01/2012
* specialy adapted to work with these accordion scripts:
* /themes/sztyle/mockup/style.css" />
* /themes/sztyle/mockup/jquery-1.4.2.min.js"></script>
* /themes/sztyle/mockup/menu.js"></script>
*************************************************************************/

function process_cat_tree( $cat ) {
 global $level; //set depth level

 $args = array(
    'category__in' => array( $cat ),
    'numberposts' => -1,
    'orderby' => 'date', // possible orderby values: 'date', 'title', 'modified', etc - see http://codex.wordpress.org/Class_Reference/WP_Query#Order_.26_Orderby_Parameters
    'order' => 'DESC');
// full query parameter list, see http://codex.wordpress.org/Class_Reference/WP_Query#Parameters

 $cat_posts = get_posts( $args );

 $next = get_categories('hide_empty=0&orderby=slug&parent=' . $cat); //fix for posts in cats with sub cats

 if( $cat_posts ) : //fix for posts in cats with sub cats

if(!$next) echo "\n   ".'<ul class="acitem indent">';//fix for posts in cats with sub cats
if($next) echo "\n   ".'<ul class="menu nestedmenu noaccordion acitem indent">';

 foreach( $cat_posts as $post ) :
 echo "\n      ".'<li>';

//BEGIN post output section//


 $post_thumb = get_the_post_thumbnail($post->ID); //get the post thumbnail - featured image
 $post_link = get_post_meta($post->ID,'_custom_featured_link',true); //get the link url from the custom field

 echo '<div class="postcontent">' . "\n";
 if($post_link) echo '<a href="'. $post_link  .'" target="_blank">'; //link tag for post
 if( $post_thumb ) echo $post_thumb . ' '; // code implemented to show thumbnail if exists
 echo $post->post_title; //post title
 if($post_link) echo '</a>'; //close link


 echo apply_filters('the_content',$post->post_content); // in case the post has some content
 echo "\n" . '</div><!--.postcontent-->';

//END post output section//

 echo "\n      ".'</li>';
 endforeach;

if(!$next) echo "\n   ".'</ul><!--/.acitem indent-->';//fix for posts in cats with sub cats
 endif; // end of if( $cat_posts ) :

 $next = get_categories('hide_empty=0&parent=' . $cat);
 $count = 0;
 if( $next ) :
  $level++; //increase depth level

    if($level == 2) echo "\n".'<ul class="menu noaccordion">';
    if(!$cat_posts && $level > 2) echo "\n   ".'<ul class="menu nestedmenu noaccordion acitem indent">'; //fix for posts in cats with sub cats
    $cat_posts = ''; //fix for posts in cats with sub cats

 foreach( $next as $cat ) :
 $count++;
    if($level == 2) echo "\n".'<li>';
    if($level > 2) echo "\n   ".'<li>';

 echo "\n".'<a href="#" class="level'. ($level-1) .'">'. $cat->name .'</a>';

 process_cat_tree( $cat->term_id );

    if($level == 2) echo "\n".'</li>';
    if($level > 2) echo "\n   ".'</li>';

 endforeach;
  $level--; //decrease depth level

    if($level == 1) echo "\n".'</ul><!--/.menu noaccordion-->';
    if($level > 1) echo "\n   ".'</ul><!--/.menu nestedmenu noaccordion acitem indent-->';
endif; //end of  if( $next )
}
//END OF function process_cat_tree( $cat )