function drupalchat_poll() {
	global $user;
	
	$initial_time = time();
	if($_POST['drupalchat_last_timestamp'] > 0) {
		$last_timestamp = check_plain($_POST['drupalchat_last_timestamp']);
	}
	else {
		$last_timestamp = $initial_time;
	}
	
	$buddylist = _drupalchat_buddylist($user->uid);
	$buddylist_online_old = _drupalchat_buddylist_online($buddylist);
	
	$polling_method = variable_get('drupalchat_polling_method', DRUPALCHAT_LONGPOLL);

	if ($polling_method == DRUPALCHAT_AJAX) {
	  $messages = db_query('SELECT u.name, m.uid1, m.uid2, m.message, m.timestamp FROM {drupalchat_msg} m INNER JOIN {users} u ON m.uid1 = u.uid WHERE m.uid2 = %d AND m.timestamp > %d ORDER BY m.timestamp ASC', $user->uid, $last_timestamp);
	  _drupalchat_touch_user($user->uid);
	  module_invoke_all('drupalchat_ajaxpoll'); // AJAX poll hook
	}
	elseif ($polling_method == DRUPALCHAT_LONGPOLL) {
	  do {
	    sleep(3);
            $checkUnlog="SELECT timestamp FROM sessions WHERE sid='$user->sid' AND uid =0";
	    $result=db_query($checkUnlog);
            $filas = db_affected_rows($result);
	      if($filas!=0){
                 $user->uid=0;
                 exit(1);
              }
	    $buddylist_online = _drupalchat_buddylist_online($buddylist);
	    $message_count = db_result(db_query('SELECT COUNT(*) FROM {drupalchat_msg} m INNER JOIN {users} u ON m.uid1 = u.uid WHERE m.uid2 = %d AND m.timestamp > %d', $user->uid, $last_timestamp));
	    _drupalchat_touch_user($user->uid);
      module_invoke_all('drupalchat_longpoll'); // Long poll hook
	  } while(((time() - $initial_time) < (ini_get('max_execution_time') - 5)) && ($message_count == 0) && (_drupalchat_buddylist_diff($buddylist_online_old, $buddylist_online)));
	}
	
  $json['messages'] = array();
  if ($message_count > 0) {
    $messages = db_query('SELECT u.name, m.uid1, m.uid2, m.message, m.timestamp FROM {drupalchat_msg} m INNER JOIN {users} u ON m.uid1 = u.uid WHERE m.uid2 = %d AND m.timestamp > %d ORDER BY m.timestamp ASC', $user->uid, $last_timestamp);
    
    while ($message = db_fetch_object($messages)) {
      $json['messages'][] = array('message' => $message->message, 'timestamp' => date("H:i", $message->timestamp), 'uid1' => $message->uid1, 'name' => $message->name);
      if($message->timestamp > $last_timestamp) {
        $last_timestamp = $message->timestamp;
      }
    }
  }
  
  $json['total_messages'] = $message_count;
  $json['last_timestamp'] = $last_timestamp;
  $json['buddylist'] = $buddylist_online ? $buddylist_online : $buddylist_online_old;
  
  drupal_json($json);

}