From 3736fd83de39631faaf36bcd68a44f61b1ca0bd9 Mon Sep 17 00:00:00 2001
From: CraftBukkit/Spigot <noreply+git-craftbukkit@papermc.io>
Date: Sat, 18 Dec 2021 11:44:34 +1100
Subject: [PATCH] SPIGOT-6836: Add more API methods in MerchantRecipe

By: Doc <nachito94@msn.com>
---
 .../world/item/trading/MerchantRecipe.patch   | 31 ++++++++++++++++---
 .../inventory/CraftMerchantRecipe.java        | 30 +++++++++++++++++-
 2 files changed, 56 insertions(+), 5 deletions(-)

diff --git a/paper-server/nms-patches/net/minecraft/world/item/trading/MerchantRecipe.patch b/paper-server/nms-patches/net/minecraft/world/item/trading/MerchantRecipe.patch
index 3652bc29f6..775e5521c9 100644
--- a/paper-server/nms-patches/net/minecraft/world/item/trading/MerchantRecipe.patch
+++ b/paper-server/nms-patches/net/minecraft/world/item/trading/MerchantRecipe.patch
@@ -9,8 +9,14 @@
  public class MerchantRecipe {
  
      public ItemStack baseCostA;
-@@ -17,6 +19,18 @@
-     private int demand;
+@@ -13,10 +15,26 @@
+     public int uses;
+     public int maxUses;
+     public boolean rewardExp;
+-    private int specialPriceDiff;
+-    private int demand;
++    public int specialPriceDiff; // PAIL private -> public
++    public int demand; // PAIL private -> public
      public float priceMultiplier;
      public int xp;
 +    // CraftBukkit start
@@ -21,14 +27,18 @@
 +    }
 +
 +    public MerchantRecipe(ItemStack itemstack, ItemStack itemstack1, ItemStack itemstack2, int uses, int maxUses, int experience, float priceMultiplier, CraftMerchantRecipe bukkit) {
-+        this(itemstack, itemstack1, itemstack2, uses, maxUses, experience, priceMultiplier);
++        this(itemstack, itemstack1, itemstack2, uses, maxUses, experience, priceMultiplier, 0, bukkit);
++    }
++
++    public MerchantRecipe(ItemStack itemstack, ItemStack itemstack1, ItemStack itemstack2, int uses, int maxUses, int experience, float priceMultiplier, int demand, CraftMerchantRecipe bukkit) {
++        this(itemstack, itemstack1, itemstack2, uses, maxUses, experience, priceMultiplier, demand);
 +        this.bukkitHandle = bukkit;
 +    }
 +    // CraftBukkit end
  
      public MerchantRecipe(NBTTagCompound nbttagcompound) {
          this.rewardExp = true;
-@@ -78,6 +92,7 @@
+@@ -78,6 +96,7 @@
  
      public ItemStack getCostA() {
          int i = this.baseCostA.getCount();
@@ -36,3 +46,16 @@
          ItemStack itemstack = this.baseCostA.copy();
          int j = Math.max(0, MathHelper.floor((float) (i * this.demand) * this.priceMultiplier));
  
+@@ -199,7 +218,11 @@
+         if (!this.satisfiedBy(itemstack, itemstack1)) {
+             return false;
+         } else {
+-            itemstack.shrink(this.getCostA().getCount());
++            // CraftBukkit start
++            if (!this.getCostA().isEmpty()) {
++                itemstack.shrink(this.getCostA().getCount());
++            }
++            // CraftBukkit end
+             if (!this.getCostB().isEmpty()) {
+                 itemstack1.shrink(this.getCostB().getCount());
+             }
diff --git a/paper-server/src/main/java/org/bukkit/craftbukkit/inventory/CraftMerchantRecipe.java b/paper-server/src/main/java/org/bukkit/craftbukkit/inventory/CraftMerchantRecipe.java
index 79e286ebe3..707c89f706 100644
--- a/paper-server/src/main/java/org/bukkit/craftbukkit/inventory/CraftMerchantRecipe.java
+++ b/paper-server/src/main/java/org/bukkit/craftbukkit/inventory/CraftMerchantRecipe.java
@@ -2,6 +2,8 @@ package org.bukkit.craftbukkit.inventory;
 
 import com.google.common.base.Preconditions;
 import java.util.List;
+import net.minecraft.util.MathHelper;
+import org.bukkit.Material;
 import org.bukkit.inventory.ItemStack;
 import org.bukkit.inventory.MerchantRecipe;
 
@@ -17,7 +19,11 @@ public class CraftMerchantRecipe extends MerchantRecipe {
     }
 
     public CraftMerchantRecipe(ItemStack result, int uses, int maxUses, boolean experienceReward, int experience, float priceMultiplier) {
-        super(result, uses, maxUses, experienceReward, experience, priceMultiplier);
+        this(result, uses, maxUses, experienceReward, experience, priceMultiplier, 0, 0);
+    }
+
+    public CraftMerchantRecipe(ItemStack result, int uses, int maxUses, boolean experienceReward, int experience, float priceMultiplier, int demand, int specialPrice) {
+        super(result, uses, maxUses, experienceReward, experience, priceMultiplier, demand, specialPrice);
         this.handle = new net.minecraft.world.item.trading.MerchantRecipe(
                 net.minecraft.world.item.ItemStack.EMPTY,
                 net.minecraft.world.item.ItemStack.EMPTY,
@@ -26,11 +32,33 @@ public class CraftMerchantRecipe extends MerchantRecipe {
                 maxUses,
                 experience,
                 priceMultiplier,
+                demand,
                 this
         );
+        this.setSpecialPrice(specialPrice);
         this.setExperienceReward(experienceReward);
     }
 
+    @Override
+    public int getSpecialPrice() {
+        return handle.getSpecialPriceDiff();
+    }
+
+    @Override
+    public void setSpecialPrice(int specialPrice) {
+        handle.specialPriceDiff = specialPrice;
+    }
+
+    @Override
+    public int getDemand() {
+        return handle.demand;
+    }
+
+    @Override
+    public void setDemand(int demand) {
+        handle.demand = demand;
+    }
+
     @Override
     public int getUses() {
         return handle.uses;