From 5e3717f8fbdc425eb88570efa92fe4c2df8187bc 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 98300d0a2..f714dc326 100644
--- a/src/main/java/net/minecraft/server/EnchantmentManager.java
+++ b/src/main/java/net/minecraft/server/EnchantmentManager.java
@@ -226,6 +226,7 @@ public class EnchantmentManager {
         return getEnchantmentLevel(Enchantments.D, 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 list = enchantment.a(entityliving);
 
diff --git a/src/main/java/net/minecraft/server/Enchantments.java b/src/main/java/net/minecraft/server/Enchantments.java
index 35e87eb1c..74a6a4f60 100644
--- a/src/main/java/net/minecraft/server/Enchantments.java
+++ b/src/main/java/net/minecraft/server/Enchantments.java
@@ -32,7 +32,7 @@ public class Enchantments {
     public static final Enchantment ARROW_INFINITE = a("infinity");
     public static final Enchantment LUCK = a("luck_of_the_sea");
     public static final Enchantment LURE = a("lure");
-    public static final Enchantment C = a("mending");
+    public static final Enchantment C = a("mending"); public static final Enchantment MENDING = C; // Paper - OBFHELPER
     public static final Enchantment D = 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 ff5cc74ba..1c59fd966 100644
--- a/src/main/java/net/minecraft/server/EntityExperienceOrb.java
+++ b/src/main/java/net/minecraft/server/EntityExperienceOrb.java
@@ -234,10 +234,12 @@ public class EntityExperienceOrb extends Entity {
         }
     }
 
+    public int durToXp(int i) { return c(i); } // Paper OBFHELPER
     private int c(int i) {
         return i / 2;
     }
 
+    public int xpToDur(int i) { return d(i); } // Paper OBFHELPER
     private int d(int i) {
         return i * 2;
     }
diff --git a/src/main/java/net/minecraft/server/ItemStack.java b/src/main/java/net/minecraft/server/ItemStack.java
index d666088f2..f6b802dc8 100644
--- a/src/main/java/net/minecraft/server/ItemStack.java
+++ b/src/main/java/net/minecraft/server/ItemStack.java
@@ -29,7 +29,7 @@ public final class ItemStack {
     private Item item;
     private NBTTagCompound tag;
     private boolean g;
-    private int damage;
+    private int damage; public void setDamage(int i) { this.damage = i; } // Paper - OBFHELPER
     private EntityItemFrame i;
     private Block j;
     private boolean k;
@@ -350,10 +350,12 @@ public final class ItemStack {
         return this.getItem().k();
     }
 
+    public boolean hasDamage() { return h(); } // Paper OBFHELPER
     public boolean h() {
         return this.f() && this.damage > 0;
     }
 
+    public int getDamage() { return i(); } // Paper OBFHELPER
     public int i() {
         return this.damage;
     }
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
index 428b208ae..21631c588 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
@@ -923,8 +923,39 @@ 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
+        ItemStack itemstack = EnchantmentManager.getRandomEquippedItemWithEnchant(Enchantments.MENDING, handle);
+        if (!itemstack.isEmpty() && itemstack.hasDamage()) {
+
+            EntityExperienceOrb orb = new 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);
     }
 
-- 
2.18.0