Consistently use 'mob head' terminology in the API

previously, we were sometimes using 'mob head' and other times 'skull', sometimes even within the same file.

src/block/MobHead.php

@@ -0,0 +1,137 @@
+<?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\MobHead as TileMobHead;
+use pocketmine\block\utils\MobHeadType;
+use pocketmine\data\runtime\RuntimeDataDescriber;
+use pocketmine\item\Item;
+use pocketmine\math\AxisAlignedBB;
+use pocketmine\math\Facing;
+use pocketmine\math\Vector3;
+use pocketmine\player\Player;
+use pocketmine\world\BlockTransaction;
+use function assert;
+use function floor;
+
+class MobHead extends Flowable{
+	public const MIN_ROTATION = 0;
+	public const MAX_ROTATION = 15;
+
+	protected MobHeadType $mobHeadType;
+
+	protected int $facing = Facing::NORTH;
+	protected int $rotation = self::MIN_ROTATION; //TODO: split this into floor skull and wall skull handling
+
+	public function __construct(BlockIdentifier $idInfo, string $name, BlockTypeInfo $typeInfo){
+		$this->mobHeadType = MobHeadType::SKELETON(); //TODO: this should be a parameter
+		parent::__construct($idInfo, $name, $typeInfo);
+	}
+
+	public function describeBlockItemState(RuntimeDataDescriber $w) : void{
+		$w->mobHeadType($this->mobHeadType);
+	}
+
+	protected function describeBlockOnlyState(RuntimeDataDescriber $w) : void{
+		$w->facingExcept($this->facing, Facing::DOWN);
+	}
+
+	public function readStateFromWorld() : Block{
+		parent::readStateFromWorld();
+		$tile = $this->position->getWorld()->getTile($this->position);
+		if($tile instanceof TileMobHead){
+			$this->mobHeadType = $tile->getMobHeadType();
+			$this->rotation = $tile->getRotation();
+		}
+
+		return $this;
+	}
+
+	public function writeStateToWorld() : void{
+		parent::writeStateToWorld();
+		//extra block properties storage hack
+		$tile = $this->position->getWorld()->getTile($this->position);
+		assert($tile instanceof TileMobHead);
+		$tile->setRotation($this->rotation);
+		$tile->setMobHeadType($this->mobHeadType);
+	}
+
+	public function getMobHeadType() : MobHeadType{
+		return $this->mobHeadType;
+	}
+
+	/** @return $this */
+	public function setMobHeadType(MobHeadType $mobHeadType) : self{
+		$this->mobHeadType = $mobHeadType;
+		return $this;
+	}
+
+	public function getFacing() : int{ return $this->facing; }
+
+	/** @return $this */
+	public function setFacing(int $facing) : self{
+		if($facing === Facing::DOWN){
+			throw new \InvalidArgumentException("Skull may not face DOWN");
+		}
+		$this->facing = $facing;
+		return $this;
+	}
+
+	public function getRotation() : int{ return $this->rotation; }
+
+	/** @return $this */
+	public function setRotation(int $rotation) : self{
+		if($rotation < self::MIN_ROTATION || $rotation > self::MAX_ROTATION){
+			throw new \InvalidArgumentException("Rotation must be in range " . self::MIN_ROTATION . " ... " . self::MAX_ROTATION);
+		}
+		$this->rotation = $rotation;
+		return $this;
+	}
+
+	/**
+	 * @return AxisAlignedBB[]
+	 */
+	protected function recalculateCollisionBoxes() : array{
+		$collisionBox = AxisAlignedBB::one()->contract(0.25, 0, 0.25)->trim(Facing::UP, 0.5);
+		return match($this->facing){
+			Facing::NORTH => [$collisionBox->offset(0, 0.25, 0.25)],
+			Facing::SOUTH => [$collisionBox->offset(0, 0.25, -0.25)],
+			Facing::WEST => [$collisionBox->offset(0.25, 0.25, 0)],
+			Facing::EAST => [$collisionBox->offset(-0.25, 0.25, 0)],
+			default => [$collisionBox]
+		};
+	}
+
+	public function place(BlockTransaction $tx, Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, ?Player $player = null) : bool{
+		if($face === Facing::DOWN){
+			return false;
+		}
+
+		$this->facing = $face;
+		if($player !== null && $face === Facing::UP){
+			$this->rotation = ((int) floor(($player->getLocation()->getYaw() * 16 / 360) + 0.5)) & 0xf;
+		}
+		return parent::place($tx, $item, $blockReplace, $blockClicked, $face, $clickVector, $player);
+	}
+}