From 39b86fa69e8d2d6404b044b90c923f766294834e 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/server/EnchantmentManager.java b/src/main/java/net/minecraft/server/EnchantmentManager.java
index fd6df39f17..f03aef2fed 100644
--- a/src/main/java/net/minecraft/server/EnchantmentManager.java
+++ b/src/main/java/net/minecraft/server/EnchantmentManager.java
@@ -223,6 +223,7 @@ public class EnchantmentManager {
         return getEnchantmentLevel(Enchantments.F, itemstack) > 0;
     }
 
+    public static ItemStack getRandomEquippedItemWithEnchant(Enchantment enchantment, EntityLiving entityliving) { return b(enchantment, entityliving); } // Paper - OBFHELPER
     public static ItemStack b(Enchantment enchantment, EntityLiving entityliving) {
         List<ItemStack> list = enchantment.a(entityliving);// Paper - decompile fix
         if (list.isEmpty()) {
diff --git a/src/main/java/net/minecraft/server/Enchantments.java b/src/main/java/net/minecraft/server/Enchantments.java
index 8cfb38b826..44b2d428b3 100644
--- a/src/main/java/net/minecraft/server/Enchantments.java
+++ b/src/main/java/net/minecraft/server/Enchantments.java
@@ -35,7 +35,7 @@ public class Enchantments {
     public static final Enchantment D = a("impaling");
     public static final Enchantment E = a("riptide");
     public static final Enchantment F = a("channeling");
-    public static final Enchantment G = a("mending");
+    public static final Enchantment G = a("mending");public static final Enchantment MENDING = G; // Paper - OBFHELPER
     public static final Enchantment H = a("vanishing_curse");
 
     @Nullable
diff --git a/src/main/java/net/minecraft/server/EntityExperienceOrb.java b/src/main/java/net/minecraft/server/EntityExperienceOrb.java
index dcef63bb1f..53cfc10017 100644
--- a/src/main/java/net/minecraft/server/EntityExperienceOrb.java
+++ b/src/main/java/net/minecraft/server/EntityExperienceOrb.java
@@ -246,10 +246,12 @@ public class EntityExperienceOrb extends Entity {
         }
     }
 
+    public int durToXp(int i) { return b(i); } // Paper OBFHELPER
     private int b(int i) {
         return i / 2;
     }
 
+    public int xpToDur(int i) { return c(i); } // Paper OBFHELPER
     private int c(int i) {
         return i * 2;
     }
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
index 0d76a42997..1c40f17ce9 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
@@ -1023,8 +1023,39 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
         return GameMode.getByValue(getHandle().playerInteractManager.getGameMode().getId());
     }
 
+    // Paper start
     @Override
-    public void giveExp(int exp) {
+    public int applyMending(int amount) {
+        EntityPlayer handle = getHandle();
+        // Logic copied from EntityExperienceOrb and remapped to unobfuscated methods/properties
+        net.minecraft.server.ItemStack itemstack = net.minecraft.server.EnchantmentManager.getRandomEquippedItemWithEnchant(net.minecraft.server.Enchantments.MENDING, handle);
+        if (!itemstack.isEmpty() && itemstack.getItem().usesDurability()) {
+
+            net.minecraft.server.EntityExperienceOrb orb = new net.minecraft.server.EntityExperienceOrb(handle.world);
+            orb.value = amount;
+            orb.spawnReason = org.bukkit.entity.ExperienceOrb.SpawnReason.CUSTOM;
+            orb.locX = handle.locX;
+            orb.locY = handle.locY;
+            orb.locZ = handle.locZ;
+
+            int i = Math.min(orb.xpToDur(amount), itemstack.getDamage());
+            org.bukkit.event.player.PlayerItemMendEvent event = org.bukkit.craftbukkit.event.CraftEventFactory.callPlayerItemMendEvent(handle, orb, itemstack, i);
+            i = event.getRepairAmount();
+            orb.dead = true;
+            if (!event.isCancelled()) {
+                amount -= orb.durToXp(i);
+                itemstack.setDamage(itemstack.getDamage() - i);
+            }
+        }
+        return amount;
+    }
+
+    @Override
+    public void giveExp(int exp, boolean applyMending) {
+        if (applyMending) {
+            exp = this.applyMending(exp);
+        }
+        // Paper end
         getHandle().giveExp(exp);
     }
 
-- 
2.19.0