Add Shulker Boxes (#3678)

this implementation is working, although incomplete:

- The shulker close sound should not be played until the end of the shulker closing animation, which takes approximately 1 second.
- An open shulker box has a different collision box than a closed one - it should be +0.5 in whichever direction the shulker is facing. (During the animation, the bounding box also dynamically changes size - you can see this in vanilla by shooting an arrow into the top of an open shulkerbox facing UP, and then closing it - the arrow will fall and collide with the lid multiple times.

However, resolving both of these issues requires significant internal changes which are beyond the scope of this PR.

src/block/ShulkerBox.php

@@ -0,0 +1,95 @@
+<?php
+
+/*
+ *
+ *  ____            _        _   __  __ _                  __  __ ____
+ * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
+ * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
+ * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
+ * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * @author PocketMine Team
+ * @link http://www.pocketmine.net/
+ *
+ *
+*/
+
+declare(strict_types=1);
+
+namespace pocketmine\block;
+
+use pocketmine\block\tile\ShulkerBox as TileShulkerBox;
+use pocketmine\block\utils\AnyFacingTrait;
+use pocketmine\item\Item;
+use pocketmine\math\Vector3;
+use pocketmine\player\Player;
+use pocketmine\world\BlockTransaction;
+
+class ShulkerBox extends Opaque{
+	use AnyFacingTrait;
+
+	public function writeStateToWorld() : void{
+		parent::writeStateToWorld();
+		$shulker = $this->pos->getWorld()->getTile($this->pos);
+		if($shulker instanceof TileShulkerBox){
+			$shulker->setFacing($this->facing);
+		}
+	}
+
+	public function readStateFromWorld() : void{
+		parent::readStateFromWorld();
+		$shulker = $this->pos->getWorld()->getTile($this->pos);
+		if($shulker instanceof TileShulkerBox){
+			$this->facing = $shulker->getFacing();
+		}
+	}
+
+	public function getMaxStackSize() : int{
+		return 1;
+	}
+
+	public function place(BlockTransaction $tx, Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
+		$this->facing = $face;
+
+		return parent::place($tx, $item, $blockReplace, $blockClicked, $face, $clickVector, $player);
+	}
+
+	public function asItem() : Item{
+		$item = parent::asItem();
+		$shulker = $this->pos->getWorld()->getTile($this->pos);
+		if($shulker instanceof TileShulkerBox){
+			$shulkerNBT = $shulker->getCleanedNBT();
+			if($shulkerNBT !== null){
+				$item->setNamedTag($shulkerNBT);
+			}
+			if($shulker->hasName()){
+				$item->setCustomName($shulker->getName());
+			}
+		}
+		return $item;
+	}
+
+	public function onInteract(Item $item, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
+		if($player instanceof Player){
+
+			$shulker = $this->pos->getWorld()->getTile($this->pos);
+			if($shulker instanceof TileShulkerBox){
+				if(
+					$this->getSide($this->facing)->getId() !== BlockLegacyIds::AIR or
+					!$shulker->canOpenWith($item->getCustomName())
+				){
+					return true;
+				}
+
+				$player->setCurrentWindow($shulker->getInventory());
+			}
+		}
+
+		return true;
+	}
+}