Implement anvil

src/block/inventory/AnvilInventory.php

@@ -25,6 +25,7 @@
 
 use pocketmine\inventory\SimpleInventory;
 use pocketmine\inventory\TemporaryInventory;
+use pocketmine\item\Item;
 use pocketmine\world\Position;
 
 class AnvilInventory extends SimpleInventory implements BlockInventory, TemporaryInventory{
@@ -37,4 +38,12 @@ public function __construct(Position $holder){
 		$this->holder = $holder;
 		parent::__construct(2);
 	}
+
+	public function getInput() : Item {
+		return $this->getItem(self::SLOT_INPUT);
+	}
+
+	public function getMaterial() : Item {
+		return $this->getItem(self::SLOT_MATERIAL);
+	}
 }

src/block/utils/AnvilHelper.php

@@ -0,0 +1,189 @@
+<?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\utils;
+
+use pocketmine\inventory\transaction\TransactionValidationException;
+use pocketmine\item\Durable;
+use pocketmine\item\EnchantedBook;
+use pocketmine\item\enchantment\AvailableEnchantmentRegistry;
+use pocketmine\item\enchantment\Enchantment;
+use pocketmine\item\enchantment\EnchantmentInstance;
+use pocketmine\item\enchantment\Rarity;
+use pocketmine\item\Item;
+use pocketmine\player\Player;
+use function ceil;
+use function floor;
+use function max;
+use function min;
+use function strlen;
+
+class AnvilHelper{
+	private const COST_REPAIR_MATERIAL = 1;
+	private const COST_REPAIR_SACRIFICE = 2;
+	private const COST_RENAME = 1;
+	private const COST_LIMIT = 39;
+
+	/**
+	 * Attempts to calculate the result of an anvil operation.
+	 *
+	 * Returns null if the operation can't do anything.
+	 */
+	public static function calculateResult(Player $player, Item $base, Item $material, ?string $customName = null) : ?AnvilResult {
+		$resultCost = 0;
+		$resultItem = clone $base;
+
+		if($resultItem instanceof Durable && $resultItem->isValidRepairMaterial($material) && $resultItem->getDamage() > 0){
+			$resultCost += self::repairWithMaterial($resultItem, $material);
+		}else{
+			if($resultItem->getTypeId() === $material->getTypeId() && $resultItem instanceof Durable && $material instanceof Durable){
+				$resultCost += self::repairWithSacrifice($resultItem, $material);
+			}
+			if($material->hasEnchantments()){
+				$resultCost += self::combineEnchantments($resultItem, $material);
+			}
+		}
+
+		// Repair cost increment if the item has been processed, the rename is free of penalty
+		$additionnalRepairCost = $resultCost > 0 ? 1 : 0;
+		$resultCost += self::renameItem($resultItem, $customName);
+
+		$resultCost += 2 ** $resultItem->getRepairCost() - 1;
+		$resultCost += 2 ** $material->getRepairCost() - 1;
+		$resultItem->setRepairCost(
+			max($resultItem->getRepairCost(), $material->getRepairCost()) + $additionnalRepairCost
+		);
+
+		if($resultCost <= 0 || ($resultCost > self::COST_LIMIT && !$player->isCreative())){
+			return null;
+		}
+
+		return new AnvilResult($resultCost, $resultItem);
+	}
+
+	/**
+	 * @return int The XP cost of repairing the item
+	 */
+	private static function repairWithMaterial(Durable $result, Item $material) : int {
+		$damage = $result->getDamage();
+		$quarter = min($damage, (int) floor($result->getMaxDurability() / 4));
+		$numberRepair = min($material->getCount(), (int) ceil($damage / $quarter));
+		if($numberRepair > 0){
+			$material->pop($numberRepair);
+			$damage -= $quarter * $numberRepair;
+		}
+		$result->setDamage(max(0, $damage));
+
+		return $numberRepair * self::COST_REPAIR_MATERIAL;
+	}
+
+	/**
+	 * @return int The XP cost of repairing the item
+	 */
+	private static function repairWithSacrifice(Durable $result, Durable $sacrifice) : int{
+		if($result->getDamage() === 0){
+			return 0;
+		}
+		$baseDurability = $result->getMaxDurability() - $result->getDamage();
+		$materialDurability = $sacrifice->getMaxDurability() - $sacrifice->getDamage();
+		$addDurability = (int) ($result->getMaxDurability() * 12 / 100);
+
+		$newDurability = min($result->getMaxDurability(), $baseDurability + $materialDurability + $addDurability);
+
+		$result->setDamage($result->getMaxDurability() - $newDurability);
+
+		return self::COST_REPAIR_SACRIFICE;
+	}
+
+	/**
+	 * @return int The XP cost of combining the enchantments
+	 */
+	private static function combineEnchantments(Item $base, Item $sacrifice) : int{
+		$cost = 0;
+		foreach($sacrifice->getEnchantments() as $instance){
+			$enchantment = $instance->getType();
+			$level = $instance->getLevel();
+			if(!AvailableEnchantmentRegistry::getInstance()->isAvailableForItem($enchantment, $base)){
+				continue;
+			}
+			if(($targetEnchantment = $base->getEnchantment($enchantment)) !== null){
+				// Enchant already present on the target item
+				$targetLevel = $targetEnchantment->getLevel();
+				$newLevel = ($targetLevel === $level ? $targetLevel + 1 : max($targetLevel, $level));
+				$level = min($newLevel, $enchantment->getMaxLevel());
+				$instance = new EnchantmentInstance($enchantment, $level);
+			}else{
+				// Check if the enchantment is compatible with the existing enchantments
+				foreach($base->getEnchantments() as $testedInstance){
+					$testedEnchantment = $testedInstance->getType();
+					if(!$testedEnchantment->isCompatibleWith($enchantment)){
+						$cost++;
+						continue 2;
+					}
+				}
+			}
+
+			$costAddition = self::getCostAddition($enchantment);
+
+			if($sacrifice instanceof EnchantedBook){
+				// Enchanted books are half as expensive to combine
+				$costAddition = max(1, $costAddition / 2);
+			}
+			$levelDifference = $instance->getLevel() - $base->getEnchantmentLevel($instance->getType());
+			$cost += $costAddition * $levelDifference;
+			$base->addEnchantment($instance);
+		}
+
+		return (int) $cost;
+	}
+
+	/**
+	 * @return int The XP cost of renaming the item
+	 */
+	private static function renameItem(Item $item, ?string $customName) : int{
+		$resultCost = 0;
+		if($customName === null || strlen($customName) === 0){
+			if($item->hasCustomName()){
+				$resultCost += self::COST_RENAME;
+				$item->clearCustomName();
+			}
+		}else{
+			if($item->getCustomName() !== $customName){
+				$resultCost += self::COST_RENAME;
+				$item->setCustomName($customName);
+			}
+		}
+
+		return $resultCost;
+	}
+
+	private static function getCostAddition(Enchantment $enchantment) : int {
+		return match($enchantment->getRarity()){
+			Rarity::COMMON => 1,
+			Rarity::UNCOMMON => 2,
+			Rarity::RARE => 4,
+			Rarity::MYTHIC => 8,
+			default => throw new TransactionValidationException("Invalid rarity " . $enchantment->getRarity() . " found")
+		};
+	}
+}

src/block/utils/AnvilResult.php

@@ -0,0 +1,41 @@
+<?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\utils;
+
+use pocketmine\item\Item;
+
+class AnvilResult{
+	public function __construct(
+		private int $repairCost,
+		private ?Item $result,
+	){}
+
+	public function getRepairCost() : int{
+		return $this->repairCost;
+	}
+
+	public function getResult() : ?Item{
+		return $this->result;
+	}
+}

src/event/player/PlayerUseAnvilEvent.php

@@ -0,0 +1,86 @@
+<?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\event\player;
+
+use pocketmine\event\Cancellable;
+use pocketmine\event\CancellableTrait;
+use pocketmine\item\Item;
+use pocketmine\player\Player;
+
+/**
+ * Called when a player uses an anvil (renaming, repairing, combining items).
+ * This event is called once per action even if multiple tasks are performed at once.
+ */
+class PlayerUseAnvilEvent extends PlayerEvent implements Cancellable{
+	use CancellableTrait;
+
+	public function __construct(
+		Player $player,
+		private Item $baseItem,
+		private ?Item $materialItem,
+		private Item $resultItem,
+		private ?string $customName,
+		private int $xpCost
+	){
+		$this->player = $player;
+	}
+
+	/**
+	 * Returns the item that the player is using as the base item (left slot).
+	 */
+	public function getBaseItem() : Item{
+		return $this->baseItem;
+	}
+
+	/**
+	 * Returns the item that the player is using as the material item (right slot), or null if there is no material item
+	 * (e.g. when renaming an item).
+	 */
+	public function getMaterialItem() : ?Item{
+		return $this->materialItem;
+	}
+
+	/**
+	 * Returns the item that the player will receive as a result of the anvil operation.
+	 */
+	public function getResultItem() : Item{
+		return $this->resultItem;
+	}
+
+	/**
+	 * Returns the custom name that the player is setting on the item, or null if the player is not renaming the item.
+	 *
+	 * This value is defined when the base item is already renamed.
+	 */
+	public function getCustomName() : ?string{
+		return $this->customName;
+	}
+
+	/**
+	 * Returns the amount of XP levels that the player will spend on this anvil operation.
+	 */
+	public function getXpCost() : int{
+		return $this->xpCost;
+	}
+}