<?php

namespace InventoryMenuExample;

use pocketmine\plugin\PluginBase;
use pocketmine\event\Listener;
use pocketmine\event\player\PlayerJoinEvent;
use pocketmine\item\Item;
use InventoryMenu\event\InventoryClickEvent;

class Main extends PluginBase implements Listener {

	/** @var InventoryMenu */
	private $inventoryMenu;

	public function onEnable() {
		$this->getServer()->getPluginManager()->registerEvents($this, $this);
		$this->inventoryMenu =  $this->getServer()->getPluginManager()->getPlugin("InventoryMenuAPI");
	}

	public function onPlayerJoin(PlayerJoinEvent $event) {
		$player = $event->getPlayer();
		$items = [Item::get(1, 0, 1), Item::get(2, 0, 2)];
		$chestId = 0;
		$title = "Example!";
		$this->inventoryMenu->createChest($player, $items, $chestId, $title);
	}

	public function onInventoryClick(InventoryClickEvent $event) {
		if($event->getChestId() == 0) {
			if($event->getItem()->getId() == 1) {
				$event->getPlayer()->sendMessage("You select stone block");
			}
			// OR
			if$event->getSlot() == 1) {
				$event->getPlayer()->sendMessage("You select grass block");
			}
		}
	}

}