PaperMC/patches/unapplied/server/0162-Ability-to-apply-mending-to-XP-API.patch

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.

== AT ==
public net.minecraft.world.entity.ExperienceOrb durabilityToXp(I)I
public net.minecraft.world.entity.ExperienceOrb xpToDurability(I)I

diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
index 24339928fc75bc227a15921fb0a197a003ba0e5c..8b9fdcbea2dd31ca2d79b31cc389afdc792a9423 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
@@ -1665,7 +1665,41 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
     }
 
     @Override
-    public void giveExp(int exp) {
+    // Paper start - ability to apply mending
+    public int applyMending(int amount) {
+        ServerPlayer handle = this.getHandle();
+        // Logic copied from EntityExperienceOrb and remapped to unobfuscated methods/properties
+
+        final Optional<net.minecraft.world.item.enchantment.EnchantedItemInUse> stackEntry = net.minecraft.world.item.enchantment.EnchantmentHelper
+            .getRandomItemWith(net.minecraft.world.item.enchantment.EnchantmentEffectComponents.REPAIR_WITH_XP, handle, net.minecraft.world.item.ItemStack::isDamaged);
+        final net.minecraft.world.item.ItemStack itemstack = stackEntry.map(net.minecraft.world.item.enchantment.EnchantedItemInUse::itemStack).orElse(net.minecraft.world.item.ItemStack.EMPTY);
+        if (!itemstack.isEmpty() && itemstack.getItem().components().has(net.minecraft.core.component.DataComponents.MAX_DAMAGE)) {
+            net.minecraft.world.entity.ExperienceOrb orb = net.minecraft.world.entity.EntityType.EXPERIENCE_ORB.create(handle.level(), net.minecraft.world.entity.EntitySpawnReason.COMMAND);
+            orb.value = amount;
+            orb.spawnReason = org.bukkit.entity.ExperienceOrb.SpawnReason.CUSTOM;
+            orb.setPosRaw(handle.getX(), handle.getY(), handle.getZ());
+
+            final int possibleDurabilityFromXp = net.minecraft.world.item.enchantment.EnchantmentHelper.modifyDurabilityToRepairFromXp(
+                handle.serverLevel(), itemstack, amount
+            );
+            int i = Math.min(possibleDurabilityFromXp, itemstack.getDamageValue());
+            org.bukkit.event.player.PlayerItemMendEvent event = org.bukkit.craftbukkit.event.CraftEventFactory.callPlayerItemMendEvent(handle, orb, itemstack, stackEntry.get().inSlot(), i);
+            i = event.getRepairAmount();
+            orb.discard(org.bukkit.event.entity.EntityRemoveEvent.Cause.DESPAWN);
+            if (!event.isCancelled()) {
+                amount -= i * amount / possibleDurabilityFromXp;
+                itemstack.setDamageValue(itemstack.getDamageValue() - i);
+            }
+        }
+        return amount;
+    }
+
+    @Override
+    public void giveExp(int exp, boolean applyMending) {
+        if (applyMending) {
+            exp = this.applyMending(exp);
+        }
+    // Paper end - ability to apply mending
         this.getHandle().giveExperiencePoints(exp);
     }