Cooldown?

How to make cooldown in plugin using time() ? Some ideas?

 

I made something like that from code in other plugins like from antispam. It's working in 50% because when i throw this snowball at first time it's send's me "You can throw pearls every 5 seconds" but 2rd time it's doing nothing. Any ideas how to repair this?

PHP:

      $player = $shooter;
      $player_name = $shooter->getName();
      $cooldown = 5;
      if(isset($this->cooldown[$player_name]))
      {
        $last_chat_time = $this->cooldown[$player_name];
        if((time() - $last_chat_time) <= $cooldown)
        {
          $timeDifference = (time() - $last_chat_time);
          $player->sendMessage("§7You can throw pearl every 5 seconds!");
          $event->setCancelled();
        }
      }
      else
      {
        $this->cooldown[$player_name] = time();
                        $shooter->teleport($posTo);
                        if(!$shooter->isCreative()){
                            $ev = new EntityDamageEvent( $shooter, EntityDamageEvent::CAUSE_MAGIC, $this->config->get("damage") );
                            $shooter->attack($ev->getFinalDamage(), $ev);
                        }
                }