Timer code doesnt work

PHP:

<?php

namespace GetDown;

use pocketmine\Player;
use pocketmine\Server;
use pocketmine\scheduler\PluginTask;
use pocketmine\utils\Config;
use pocketmine\utils\TextFormat;
use pocketmine\utils\TextFormat as C;
use GetDown\Main;
use pocketmine\math\Vector3;
use pocketmine\plugin\Plugin;

class Timer extends PluginTask
{
    private $plugin;
    public $tts;

    public function __construct(Main $plugin)
    {
        $this->plugin = $plugin;
        $this->tts = 30;
        parent::__construct($plugin);
    }

    /**
     * @param $currentTick
     */
    public function onRun($currentTick)
    {
        foreach ($this->plugin->getServer()->getLevelByName("GDHub")->getPlayers() as $pl) {
            if (count($pl) >= 1) {
                $this->tts--;
                $pl->setExpLevel($pl->getExpLevel() - 1);
                $pl->sendPopup("");
                //$this->plugin->getServer()->shutdown();
                /*if ($this->tts == 30) {
                    $pl->sendMessage($this->plugin->gameprefix . C::GREEN . "Game start in " . $this->tts);
                    if ($this->tts == 15) {
                        $pl->sendMessage($this->plugin->gameprefix . C::GREEN . "Game start in " . $this->tts);
                        if ($this->tts == 10) {
                            $pl->sendMessage($this->plugin->gameprefix . C::GREEN . "Game start in " . $this->tts);
                            if ($this->tts == 5) {
                                $pl->sendMessage($this->plugin->gameprefix . C::GREEN . "Game start in " . $this->tts);
                                if ($this->tts == 4) {
                                    $pl->sendMessage($this->plugin->gameprefix . C::GREEN . "Game start in " . $this->tts);
                                    if ($this->tts == 3) {
                                        $pl->sendMessage($this->plugin->gameprefix . C::GREEN . "Game start in " . $this->tts);
                                        if ($this->tts == 2) {*/
                //$pl->sendMessage($this->plugin->gameprefix . C::GREEN . "Game start in " . $this->tts);
                if ($this->tts == 1) {
                    $pl->sendMessage($this->plugin->gameprefix . C::GREEN . "Game start in " . $this->tts);
                    if ($this->tts == 0) {
                        $this->plugin->getServer()->getScheduler()->cancelTask($this->getTaskId());
                        $pl->sendMessage($this->plugin->gameprefix . C::GREEN . "Game started!");
                        $this->plugin->changePhase(2);
                        $pl->teleport(new Vector3(1, 1, 1, "GD1"));
                    }
                }
            }
        }
                                        }

}

It work but it use

PHP:

if ($this->tts == 1) {
                    $pl->sendMessage($this->plugin->gameprefix . C::GREEN . "Game start in " . $this->tts);

and not use

PHP:

  if ($this->tts == 0) {
                        $pl->sendMessage($this->plugin->gameprefix . C::GREEN . "Game started!");
                        $this->plugin->changePhase(2);
                        $pl->teleport(new Vector3(1, 1, 1, "GD1"));
$this->plugin->getServer()->getScheduler()->cancelTask($this->getTaskId());

when i use first

PHP:

 
if ($this->tts == 1) {
    $pl->sendMessage($this->plugin->gameprefix . C::GREEN . "Game start in " . $this->tts);
                     


it not use

PHP:

  if ($this->tts == 0) {
                        $this->plugin->getServer()->getScheduler()->cancelTask($this->getTaskId());
                        $pl->sendMessage($this->plugin->gameprefix . C::GREEN . "Game started!");
                        $this->plugin->changePhase(2);
                        $pl->teleport(new Vector3(1, 1, 1, "GD1"));