Compteur qui ne marche pas

<?php
    $num = 1;
 $nom_dossier= $data['id_cli'];
$structure = 'commande/'.$nom_dossier.'/';
mkdir($structure,0777,true); 
$structure = 'commande/'.$nom_dossier.'/';
$chemin = ''.$structure.'com_'.$num.'.pdf';
  $file = 'com_'.$num.'.pdf';
  $file_url=''.$structure.''.$file.'';
$envoie = $bd->query('SELECT lib_com from commande WHERE lib_com = "'.$file.'" AND id_cli="'.$_SESSION['id_cli'].'"' );
$resultat=$envoie->fetch();
 if(!empty($resultat['lib_com']) )
 {
  $num_new = $num++;
  $file = 'com_'.$num_new.'.pdf';
  $envoie = $bd->prepare('INSERT INTO commande (date_com,id_cli,lib_com,url_file) VALUES(:date_com,:id_cli,:lib_com,:url_file)');
$resultat=$envoie->execute (array('date_com'=>$today,'id_cli'=>$_SESSION['id_cli'],'lib_com'=>$file,'url_file'=>$file_url));
$delete_panier= $bd->query("DELETE FROM panier WHERE cookie='".$cookie."'");
 } else { $num = 1; 
  $file = 'com_'.$num.'.pdf';
 $envoie = $bd->prepare('INSERT INTO commande (date_com,id_cli,lib_com,url_file) VALUES(:date_com,:id_cli,:lib_com,:url_file)');
 $resultat=$envoie->execute (array('date_com'=>$today,'id_cli'=>$_SESSION['id_cli'],'lib_com'=>$file,'url_file'=>$file_url));
 $delete_panier= $bd->query("DELETE FROM panier WHERE cookie='".$cookie."'");
}
?>