From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Wed, 20 Dec 2017 17:36:49 -0500
Subject: [PATCH] Ability to apply mending to XP API

This allows plugins that give players the ability to apply the experience
points to the Item Mending formula, which will repair an item instead
of giving the player experience points.

Both an API To standalone mend, and apply mending logic to .giveExp has been added.

diff --git a/src/main/java/net/minecraft/world/entity/ExperienceOrb.java b/src/main/java/net/minecraft/world/entity/ExperienceOrb.java
index 4a6a588eeeee3aa7d33d4b4545e9b8bdf043e567..30a3facc1b23ccb508b30c5affa9ea1c527dd48b 100644
--- a/src/main/java/net/minecraft/world/entity/ExperienceOrb.java
+++ b/src/main/java/net/minecraft/world/entity/ExperienceOrb.java
@@ -341,10 +341,12 @@ public class ExperienceOrb extends Entity {
         }
     }
 
+    public final int durToXp(int i) { return durabilityToXp(i); } // Paper OBFHELPER
     private int durabilityToXp(int repairAmount) {
         return repairAmount / 2;
     }
 
+    public final int xpToDur(int i) { return xpToDurability(i); } // Paper OBFHELPER
     private int xpToDurability(int experienceAmount) {
         return experienceAmount * 2;
     }
diff --git a/src/main/java/net/minecraft/world/item/enchantment/EnchantmentHelper.java b/src/main/java/net/minecraft/world/item/enchantment/EnchantmentHelper.java
index 27cdfbeb6cb2159075b35dd4f9e9557ec0eac7c2..069ce59faab5184ab9da8ca3fe1cebf7449cd7fe 100644
--- a/src/main/java/net/minecraft/world/item/enchantment/EnchantmentHelper.java
+++ b/src/main/java/net/minecraft/world/item/enchantment/EnchantmentHelper.java
@@ -246,8 +246,11 @@ public class EnchantmentHelper {
         return getItemEnchantmentLevel(Enchantments.CHANNELING, stack) > 0;
     }
 
-    @Nullable
-    public static Entry<EquipmentSlot, ItemStack> getRandomItemWith(Enchantment enchantment, LivingEntity entity) {
+    public static @javax.annotation.Nonnull ItemStack getRandomEquippedItemWithEnchant(Enchantment enchantment, LivingEntity entityliving) {
+        Entry<EquipmentSlot, ItemStack> entry = getRandomItemWith(enchantment, entityliving);
+        return entry != null ? entry.getValue() : ItemStack.EMPTY;
+    } // Paper - OBFHELPER
+    @Nullable public static Entry<EquipmentSlot, ItemStack> getRandomItemWith(Enchantment enchantment, LivingEntity entity) {
         return getRandomItemWith(enchantment, entity, (stack) -> {
             return true;
         });
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
index 1af5e3f3389d5f4e391f05b3f8e7df9d3c799981..7c6e1348cc26c38a844b7324a8372266579e048e 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
@@ -61,11 +61,14 @@ import net.minecraft.server.level.ServerPlayer;
 import net.minecraft.server.network.ServerGamePacketListenerImpl;
 import net.minecraft.server.players.UserWhiteListEntry;
 import net.minecraft.world.entity.Entity;
+import net.minecraft.world.entity.ExperienceOrb;
 import net.minecraft.world.entity.LivingEntity;
 import net.minecraft.world.entity.ai.attributes.AttributeInstance;
 import net.minecraft.world.entity.ai.attributes.AttributeMap;
 import net.minecraft.world.entity.ai.attributes.Attributes;
 import net.minecraft.world.inventory.AbstractContainerMenu;
+import net.minecraft.world.item.enchantment.EnchantmentHelper;
+import net.minecraft.world.item.enchantment.Enchantments;
 import net.minecraft.world.level.GameType;
 import net.minecraft.world.level.block.Blocks;
 import net.minecraft.world.level.block.entity.SignBlockEntity;
@@ -1198,8 +1201,37 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
         return GameMode.getByValue(this.getHandle().gameMode.getGameModeForPlayer().getId());
     }
 
+    // Paper start
+    @Override
+    public int applyMending(int amount) {
+        ServerPlayer handle = getHandle();
+        // Logic copied from EntityExperienceOrb and remapped to unobfuscated methods/properties
+        net.minecraft.world.item.ItemStack itemstack = EnchantmentHelper.getRandomEquippedItemWithEnchant(Enchantments.MENDING, handle);
+        if (!itemstack.isEmpty() && itemstack.getItem().canBeDepleted()) {
+
+            ExperienceOrb orb = net.minecraft.world.entity.EntityType.EXPERIENCE_ORB.create(handle.level);
+            orb.value = amount;
+            orb.spawnReason = org.bukkit.entity.ExperienceOrb.SpawnReason.CUSTOM;
+            orb.setPosRaw(handle.getX(), handle.getY(), handle.getZ());
+
+            int i = Math.min(orb.xpToDur(amount), itemstack.getDamageValue());
+            org.bukkit.event.player.PlayerItemMendEvent event = org.bukkit.craftbukkit.event.CraftEventFactory.callPlayerItemMendEvent(handle, orb, itemstack, i);
+            i = event.getRepairAmount();
+            orb.discard();
+            if (!event.isCancelled()) {
+                amount -= orb.durToXp(i);
+                itemstack.setDamageValue(itemstack.getDamageValue() - i);
+            }
+        }
+        return amount;
+    }
+
     @Override
-    public void giveExp(int exp) {
+    public void giveExp(int exp, boolean applyMending) {
+        if (applyMending) {
+            exp = this.applyMending(exp);
+        }
+        // Paper end
         this.getHandle().giveExperiencePoints(exp);
     }