first look at anvil actions

src/block/anvil/AnvilAction.php

@@ -0,0 +1,52 @@
+<?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\anvil;
+
+use pocketmine\item\Item;
+
+abstract class AnvilAction{
+	protected int $xpCost = 0;
+
+	public function __construct(
+		protected Item $base,
+		protected Item $material,
+		protected ?string $customName
+	){ }
+
+	final public function getXpCost() : int{
+		return $this->xpCost;
+	}
+
+	/**
+	 * If only actions marked as free of repair cost is applied, the result item
+	 * will not have any repair cost increase.
+	 */
+	public function isFreeOfRepairCost() : bool {
+		return false;
+	}
+
+	abstract public function process(Item $resultItem) : void;
+
+	abstract public function canBeApplied() : bool;
+}

src/block/anvil/AnvilActionsFactory.php

@@ -0,0 +1,71 @@
+<?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\anvil;
+
+use pocketmine\item\Item;
+use pocketmine\utils\SingletonTrait;
+use function is_subclass_of;
+
+final class AnvilActionsFactory{
+	use SingletonTrait;
+
+	/** @var array<class-string<AnvilAction>, true> */
+	private array $actions = [];
+
+	private function __construct(){
+		$this->register(RenameItemAction::class);
+		$this->register(CombineEnchantmentsAction::class);
+		$this->register(RepairWithSacrificeAction::class);
+		$this->register(RepairWithMaterialAction::class);
+	}
+
+	/**
+	 * @param class-string<AnvilAction> $class
+	 */
+	public function register(string $class) : void{
+		if(!is_subclass_of($class, AnvilAction::class, true)){
+			throw new \InvalidArgumentException("Class $class is not an AnvilAction");
+		}
+		if(isset($this->actions[$class])){
+			throw new \InvalidArgumentException("Class $class is already registered");
+		}
+		$this->actions[$class] = true;
+	}
+
+	/**
+	 * Return all available actions for the given items.
+	 *
+	 * @return AnvilAction[]
+	 */
+	public function getActions(Item $base, Item $material, ?string $customName) : array{
+		$actions = [];
+		foreach($this->actions as $class => $_){
+			$action = new $class($base, $material, $customName);
+			if($action->canBeApplied()){
+				$actions[] = $action;
+			}
+		}
+		return $actions;
+	}
+}

src/block/anvil/CombineEnchantmentsAction.php

@@ -0,0 +1,81 @@
+<?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\anvil;
+
+use pocketmine\inventory\transaction\TransactionValidationException;
+use pocketmine\item\EnchantedBook;
+use pocketmine\item\enchantment\AvailableEnchantmentRegistry;
+use pocketmine\item\enchantment\EnchantmentInstance;
+use pocketmine\item\enchantment\Rarity;
+use pocketmine\item\Item;
+use function max;
+use function min;
+
+final class CombineEnchantmentsAction extends AnvilAction{
+	public function canBeApplied() : bool{
+		return $this->material->hasEnchantments();
+	}
+
+	public function process(Item $resultItem) : void{
+		foreach($this->material->getEnchantments() as $instance){
+			$enchantment = $instance->getType();
+			$level = $instance->getLevel();
+			if(!AvailableEnchantmentRegistry::getInstance()->isAvailableForItem($enchantment, $this->base)){
+				continue;
+			}
+			if(($targetEnchantment = $this->base->getEnchantment($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, $level);
+			}else{
+				// Check if the enchantment is compatible with the existing enchantments
+				foreach($this->base->getEnchantments() as $testedInstance){
+					$testedEnchantment = $testedInstance->getType();
+					if(!$testedEnchantment->isCompatibleWith($enchantment)){
+						$this->xpCost++;
+						continue 2;
+					}
+				}
+			}
+
+			$costAddition = match($enchantment->getRarity()){
+				Rarity::COMMON => 1,
+				Rarity::UNCOMMON => 2,
+				Rarity::RARE => 4,
+				Rarity::MYTHIC => 8,
+				default => throw new TransactionValidationException("Invalid rarity " . $enchantment->getRarity() . " found")
+			};
+
+			if($this->material instanceof EnchantedBook){
+				// Enchanted books are half as expensive to combine
+				$costAddition = max(1, $costAddition / 2);
+			}
+			$levelDifference = $instance->getLevel() - $this->base->getEnchantmentLevel($instance->getType());
+			$this->xpCost += $costAddition * $levelDifference;
+			$resultItem->addEnchantment($instance);
+		}
+	}
+}

src/block/anvil/RenameItemAction.php

@@ -0,0 +1,49 @@
+<?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\anvil;
+
+use pocketmine\item\Item;
+use function strlen;
+
+final class RenameItemAction extends AnvilAction{
+	private const COST = 1;
+
+	public function canBeApplied() : bool{
+		return true;
+	}
+
+	public function process(Item $resultItem) : void{
+		if($this->customName === null || strlen($this->customName) === 0){
+			if($this->base->hasCustomName()){
+				$this->xpCost += self::COST;
+				$resultItem->clearCustomName();
+			}
+		}else{
+			if($this->base->getCustomName() !== $this->customName){
+				$this->xpCost += self::COST;
+				$resultItem->setCustomName($this->customName);
+			}
+		}
+	}
+}

src/block/anvil/RepairWithMaterialAction.php

@@ -0,0 +1,58 @@
+<?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\anvil;
+
+use pocketmine\item\Durable;
+use pocketmine\item\Item;
+use function assert;
+use function ceil;
+use function floor;
+use function max;
+use function min;
+
+final class RepairWithMaterialAction extends AnvilAction{
+	private const COST = 1;
+
+	public function canBeApplied() : bool{
+		return $this->base instanceof Durable &&
+			$this->base->isValidRepairMaterial($this->material) &&
+			$this->base->getDamage() > 0;
+	}
+
+	public function process(Item $resultItem) : void{
+		assert($resultItem instanceof Durable, "Result item must be durable");
+		assert($this->base instanceof Durable, "Base item must be durable");
+
+		$damage = $this->base->getDamage();
+		$quarter = min($damage, (int) floor($this->base->getMaxDurability() / 4));
+		$numberRepair = min($this->material->getCount(), (int) ceil($damage / $quarter));
+		if($numberRepair > 0){
+			$this->material->pop($numberRepair);
+			$damage -= $quarter * $numberRepair;
+		}
+		$resultItem->setDamage(max(0, $damage));
+
+		$this->xpCost = $numberRepair * self::COST;
+	}
+}

src/block/anvil/RepairWithSacrificeAction.php

@@ -0,0 +1,58 @@
+<?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\anvil;
+
+use pocketmine\item\Durable;
+use pocketmine\item\Item;
+use function assert;
+use function min;
+
+final class RepairWithSacrificeAction extends AnvilAction{
+	private const COST = 2;
+
+	public function canBeApplied() : bool{
+		return $this->base instanceof Durable &&
+			$this->material instanceof Durable &&
+			$this->base->getTypeId() === $this->material->getTypeId();
+	}
+
+	public function process(Item $resultItem) : void{
+		assert($resultItem instanceof Durable, "Result item must be durable");
+		assert($this->base instanceof Durable, "Base item must be durable");
+		assert($this->material instanceof Durable, "Material item must be durable");
+
+		if($this->base->getDamage() !== 0){
+			$baseMaxDurability = $this->base->getMaxDurability();
+			$baseDurability = $baseMaxDurability - $this->base->getDamage();
+			$materialDurability = $this->material->getMaxDurability() - $this->material->getDamage();
+			$addDurability = (int) ($baseMaxDurability * 12 / 100);
+
+			$newDurability = min($baseMaxDurability, $baseDurability + $materialDurability + $addDurability);
+
+			$resultItem->setDamage($baseMaxDurability - $newDurability);
+
+			$this->xpCost = self::COST;
+		}
+	}
+}

src/block/utils/AnvilHelper.php

@@ -23,25 +23,12 @@ 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\block\anvil\AnvilActionsFactory;
 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;
+final class AnvilHelper{
 	private const COST_LIMIT = 39;
 
 	/**
@@ -50,140 +37,30 @@ class AnvilHelper{
 	 * 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;
+		$xpCost = 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);
+		$additionnalRepairCost = 0;
+		foreach(AnvilActionsFactory::getInstance()->getActions($base, $material, $customName) as $action){
+			$action->process($resultItem);
+			if(!$action->isFreeOfRepairCost() && $action->getXpCost() > 0){
+				// Repair cost increment if the item has been processed
+				// and any of the action is not free of repair cost
+				$additionnalRepairCost = 1;
 			}
+			$xpCost += $action->getXpCost();
 		}
 
-		// 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;
+		$xpCost += 2 ** $resultItem->getRepairCost() - 1;
+		$xpCost += 2 ** $material->getRepairCost() - 1;
 		$resultItem->setRepairCost(
 			max($resultItem->getRepairCost(), $material->getRepairCost()) + $additionnalRepairCost
 		);
 
-		if($resultCost <= 0 || ($resultCost > self::COST_LIMIT && !$player->isCreative())){
+		if($xpCost <= 0 || ($xpCost > self::COST_LIMIT && !$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 " . $enchantment->getRarity() . " found")
-		};
+		return new AnvilResult($xpCost, $resultItem);
 	}
 }