From 2f70a1eefb801341cbc374bf4981f8050f99df4d Mon Sep 17 00:00:00 2001
From: "Dylan K. Taylor" <odigiman@gmail.com>
Date: Sat, 23 Jun 2018 13:36:58 +0100
Subject: [PATCH] Implemented Thorns enchantment (#2258)

This implementation is rough and can probably be improved to make it extendable, but this works for now and can be improved later.
---
 src/pocketmine/entity/Living.php              | 33 ++++++++++++++++---
 .../item/enchantment/Enchantment.php          |  2 +-
 2 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/src/pocketmine/entity/Living.php b/src/pocketmine/entity/Living.php
index 6202e9ee4..c4a354b13 100644
--- a/src/pocketmine/entity/Living.php
+++ b/src/pocketmine/entity/Living.php
@@ -34,6 +34,7 @@ use pocketmine\inventory\ArmorInventory;
 use pocketmine\inventory\ArmorInventoryEventProcessor;
 use pocketmine\item\Armor;
 use pocketmine\item\Consumable;
+use pocketmine\item\Durable;
 use pocketmine\item\enchantment\Enchantment;
 use pocketmine\item\Item;
 use pocketmine\math\Vector3;
@@ -476,6 +477,26 @@ abstract class Living extends Entity implements Damageable{
 	protected function applyPostDamageEffects(EntityDamageEvent $source) : void{
 		$this->setAbsorption(max(0, $this->getAbsorption() + $source->getModifier(EntityDamageEvent::MODIFIER_ABSORPTION)));
 		$this->damageArmor($source->getBaseDamage());
+
+		if($source instanceof EntityDamageByEntityEvent){
+			$damage = 0;
+			foreach($this->armorInventory->getContents() as $k => $item){
+				if($item instanceof Armor and ($thornsLevel = $item->getEnchantmentLevel(Enchantment::THORNS)) > 0){
+					if(mt_rand(0, 99) < $thornsLevel * 15){
+						$this->damageItem($item, 3);
+						$damage += ($thornsLevel > 10 ? $thornsLevel - 10 : 1 + mt_rand(0, 3));
+					}else{
+						$this->damageItem($item, 1); //thorns causes an extra +1 durability loss even if it didn't activate
+					}
+
+					$this->armorInventory->setItem($k, $item);
+				}
+			}
+
+			if($damage > 0){
+				$source->getDamager()->attack(new EntityDamageByEntityEvent($this, $source->getDamager(), EntityDamageEvent::CAUSE_MAGIC, $damage));
+			}
+		}
 	}
 
 	/**
@@ -490,16 +511,20 @@ abstract class Living extends Entity implements Damageable{
 		$armor = $this->armorInventory->getContents(true);
 		foreach($armor as $item){
 			if($item instanceof Armor){
-				$item->applyDamage($durabilityRemoved);
-				if($item->isBroken()){
-					$this->level->broadcastLevelSoundEvent($this, LevelSoundEventPacket::SOUND_BREAK);
-				}
+				$this->damageItem($item, $durabilityRemoved);
 			}
 		}
 
 		$this->armorInventory->setContents($armor);
 	}
 
+	private function damageItem(Durable $item, int $durabilityRemoved) : void{
+		$item->applyDamage($durabilityRemoved);
+		if($item->isBroken()){
+			$this->level->broadcastLevelSoundEvent($this, LevelSoundEventPacket::SOUND_BREAK);
+		}
+	}
+
 	public function attack(EntityDamageEvent $source) : void{
 		if($this->attackTime > 0 or $this->noDamageTicks > 0){
 			$lastCause = $this->getLastDamageCause();
diff --git a/src/pocketmine/item/enchantment/Enchantment.php b/src/pocketmine/item/enchantment/Enchantment.php
index 9d40e7758..e410a0d16 100644
--- a/src/pocketmine/item/enchantment/Enchantment.php
+++ b/src/pocketmine/item/enchantment/Enchantment.php
@@ -114,7 +114,7 @@ class Enchantment{
 		self::registerEnchantment(new ProtectionEnchantment(self::PROJECTILE_PROTECTION, "%enchantment.protect.projectile", self::RARITY_UNCOMMON, self::SLOT_ARMOR, self::SLOT_NONE, 4, 1.5, [
 			EntityDamageEvent::CAUSE_PROJECTILE
 		]));
-
+		self::registerEnchantment(new Enchantment(self::THORNS, "%enchantment.thorns", self::RARITY_MYTHIC, self::SLOT_TORSO, self::SLOT_HEAD | self::SLOT_LEGS | self::SLOT_FEET, 3));
 		self::registerEnchantment(new Enchantment(self::RESPIRATION, "%enchantment.oxygen", self::RARITY_RARE, self::SLOT_HEAD, self::SLOT_NONE, 3));
 
 		self::registerEnchantment(new Enchantment(self::EFFICIENCY, "%enchantment.digging", self::RARITY_COMMON, self::SLOT_DIG, self::SLOT_SHEARS, 5));