From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jake Potrebic <jake.m.potrebic@gmail.com>
Date: Sun, 8 May 2022 13:35:45 -0700
Subject: [PATCH] ItemStack damage API

Adds methods notify clients about item breaks and
to simulate damage done to an itemstack and all
the logic associated with damaging them

== AT ==
public net.minecraft.world.entity.LivingEntity entityEventForEquipmentBreak(Lnet/minecraft/world/entity/EquipmentSlot;)B

diff --git a/src/main/java/net/minecraft/world/item/ItemStack.java b/src/main/java/net/minecraft/world/item/ItemStack.java
index acce1b72185d4687ef5a72dd4014d87149f4b092..dc473b46394b41d951b68ed0eb6993e6807a0d29 100644
--- a/src/main/java/net/minecraft/world/item/ItemStack.java
+++ b/src/main/java/net/minecraft/world/item/ItemStack.java
@@ -713,7 +713,14 @@ public final class ItemStack implements DataComponentHolder {
                     return;
                 }
             }
+    // Paper start - ItemStack damage API - split hurtAndBreak to skip pre-checks like creative mode
+            this.hurtAndBreakWithoutChecks(amount, entity, slot);
+        }
+    }
 
+    public void hurtAndBreakWithoutChecks(int amount, LivingEntity entity, @org.checkerframework.checker.nullness.qual.Nullable EquipmentSlot slot) {
+        {
+    // Paper end - ItemStack damage API - split hurtAndBreak to skip pre-checks like creative mode
             RandomSource randomsource = entity.getRandom();
             ServerPlayer entityplayer;
 
@@ -726,7 +733,7 @@ public final class ItemStack implements DataComponentHolder {
             }
 
             this.hurtAndBreak(amount, randomsource, entity, () -> { // Paper - Add EntityDamageItemEvent
-                entity.broadcastBreakEvent(slot);
+                if (slot != null) entity.broadcastBreakEvent(slot); // Paper - ItemStack damage API - slot is nullable
                 Item item = this.getItem();
                 // CraftBukkit start - Check for item breaking
                 if (this.count == 1 && entity instanceof net.minecraft.world.entity.player.Player) {
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
index 2537d4d4ec1243f3b80ec13a6b863ec6de619919..6cf60ff71e398dbf6110f94a00e9bb973916a7f8 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
@@ -1103,4 +1103,48 @@ public class CraftLivingEntity extends CraftEntity implements LivingEntity {
         this.getHandle().knockback(strength, directionX, directionZ);
     };
     // Paper end - knockback API
+
+    // Paper start - ItemStack damage API
+    public void broadcastSlotBreak(final org.bukkit.inventory.EquipmentSlot slot) {
+        this.getHandle().broadcastBreakEvent(org.bukkit.craftbukkit.CraftEquipmentSlot.getNMS(slot));
+    }
+
+    @Override
+    public void broadcastSlotBreak(final org.bukkit.inventory.EquipmentSlot slot, final Collection<org.bukkit.entity.Player> players) {
+        if (players.isEmpty()) {
+            return;
+        }
+        final net.minecraft.network.protocol.game.ClientboundEntityEventPacket packet = new net.minecraft.network.protocol.game.ClientboundEntityEventPacket(
+            this.getHandle(),
+            net.minecraft.world.entity.LivingEntity.entityEventForEquipmentBreak(org.bukkit.craftbukkit.CraftEquipmentSlot.getNMS(slot))
+        );
+        players.forEach(player -> ((CraftPlayer) player).getHandle().connection.send(packet));
+    }
+
+    @Override
+    public ItemStack damageItemStack(ItemStack stack, final int amount) {
+        final net.minecraft.world.item.ItemStack nmsStack;
+        if (stack instanceof final CraftItemStack craftItemStack) {
+            if (craftItemStack.handle == null || craftItemStack.handle.isEmpty()) {
+                return stack;
+            }
+            nmsStack = craftItemStack.handle;
+        } else {
+            nmsStack = CraftItemStack.asNMSCopy(stack);
+            stack = CraftItemStack.asCraftMirror(nmsStack); // mirror to capture changes in hurt logic & events
+        }
+        this.damageItemStack0(nmsStack, amount, null);
+        return stack;
+    }
+
+    @Override
+    public void damageItemStack(final org.bukkit.inventory.EquipmentSlot slot, final int amount) {
+        final net.minecraft.world.entity.EquipmentSlot nmsSlot = org.bukkit.craftbukkit.CraftEquipmentSlot.getNMS(slot);
+        this.damageItemStack0(this.getHandle().getItemBySlot(nmsSlot), amount, nmsSlot);
+    }
+
+    private void damageItemStack0(final net.minecraft.world.item.ItemStack nmsStack, final int amount, final net.minecraft.world.entity.EquipmentSlot slot) {
+        nmsStack.hurtAndBreakWithoutChecks(amount, this.getHandle(), slot);
+    }
+    // Paper end - ItemStack damage API
 }