Add TradeSelectEvent

By: Coleman Yantis <diamonddagger590@gmail.com>

paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftAbstractVillager.java

@@ -14,8 +14,6 @@ import org.bukkit.inventory.MerchantRecipe;
 
 public class CraftAbstractVillager extends CraftAgeable implements AbstractVillager, InventoryHolder {
 
-    private CraftMerchant merchant;
-
     public CraftAbstractVillager(CraftServer server, EntityVillagerAbstract entity) {
         super(server, entity);
     }
@@ -36,7 +34,7 @@ public class CraftAbstractVillager extends CraftAgeable implements AbstractVilla
     }
 
     private CraftMerchant getMerchant() {
-        return (merchant == null) ? merchant = new CraftMerchant(getHandle()) : merchant;
+        return getHandle().getCraftMerchant();
     }
 
     @Override

paper-server/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java

@@ -2,6 +2,7 @@ package org.bukkit.craftbukkit.event;
 
 import com.google.common.base.Function;
 import com.google.common.base.Functions;
+import com.google.common.base.Preconditions;
 import com.google.common.collect.Lists;
 import com.mojang.datafixers.util.Either;
 import java.net.InetAddress;
@@ -16,6 +17,7 @@ import net.minecraft.server.BlockPropertyInstrument;
 import net.minecraft.server.ChatMessage;
 import net.minecraft.server.ChatModifier;
 import net.minecraft.server.Container;
+import net.minecraft.server.ContainerMerchant;
 import net.minecraft.server.DamageSource;
 import net.minecraft.server.DimensionManager;
 import net.minecraft.server.Entity;
@@ -161,6 +163,7 @@ import org.bukkit.event.inventory.InventoryCloseEvent;
 import org.bukkit.event.inventory.InventoryOpenEvent;
 import org.bukkit.event.inventory.PrepareAnvilEvent;
 import org.bukkit.event.inventory.PrepareItemCraftEvent;
+import org.bukkit.event.inventory.TradeSelectEvent;
 import org.bukkit.event.player.PlayerBedEnterEvent;
 import org.bukkit.event.player.PlayerBedEnterEvent.BedEnterResult;
 import org.bukkit.event.player.PlayerBucketEmptyEvent;
@@ -179,6 +182,8 @@ import org.bukkit.event.server.ServerListPingEvent;
 import org.bukkit.event.vehicle.VehicleCreateEvent;
 import org.bukkit.inventory.EquipmentSlot;
 import org.bukkit.inventory.InventoryView;
+import org.bukkit.inventory.Merchant;
+import org.bukkit.inventory.MerchantInventory;
 import org.bukkit.inventory.meta.BookMeta;
 import org.bukkit.potion.PotionEffect;
 
@@ -244,6 +249,15 @@ public class CraftEventFactory {
         return nmsBedResult;
     }
 
+    /**
+     * Trade Index Change Event
+     */
+    public static TradeSelectEvent callTradeSelectEvent(EntityPlayer player, int newIndex, ContainerMerchant merchant) {
+        TradeSelectEvent tradeSelectEvent = new TradeSelectEvent(merchant.getBukkitView(), newIndex);
+        Bukkit.getPluginManager().callEvent(tradeSelectEvent);
+        return tradeSelectEvent;
+    }
+
     /**
      * Block place methods
      */

paper-server/src/main/java/org/bukkit/craftbukkit/inventory/CraftInventoryMerchant.java

@@ -1,13 +1,18 @@
 package org.bukkit.craftbukkit.inventory;
 
+import net.minecraft.server.IMerchant;
 import net.minecraft.server.InventoryMerchant;
+import org.bukkit.inventory.Merchant;
 import org.bukkit.inventory.MerchantInventory;
 import org.bukkit.inventory.MerchantRecipe;
 
 public class CraftInventoryMerchant extends CraftInventory implements MerchantInventory {
 
-    public CraftInventoryMerchant(InventoryMerchant merchant) {
-        super(merchant);
+    private final IMerchant merchant;
+
+    public CraftInventoryMerchant(IMerchant merchant, InventoryMerchant inventory) {
+        super(inventory);
+        this.merchant = merchant;
     }
 
     @Override
@@ -25,4 +30,9 @@ public class CraftInventoryMerchant extends CraftInventory implements MerchantIn
     public InventoryMerchant getInventory() {
         return (InventoryMerchant) inventory;
     }
+
+    @Override
+    public Merchant getMerchant() {
+        return merchant.getCraftMerchant();
+    }
 }

paper-server/src/main/java/org/bukkit/craftbukkit/inventory/CraftMerchantCustom.java

@@ -14,6 +14,7 @@ public class CraftMerchantCustom extends CraftMerchant {
 
     public CraftMerchantCustom(String title) {
         super(new MinecraftMerchant(title));
+        getMerchant().craftMerchant = this;
     }
 
     @Override
@@ -32,12 +33,18 @@ public class CraftMerchantCustom extends CraftMerchant {
         private final MerchantRecipeList trades = new MerchantRecipeList();
         private EntityHuman tradingPlayer;
         private World tradingWorld;
+        protected CraftMerchant craftMerchant;
 
         public MinecraftMerchant(String title) {
             Validate.notNull(title, "Title cannot be null");
             this.title = new ChatComponentText(title);
         }
 
+        @Override
+        public CraftMerchant getCraftMerchant() {
+            return craftMerchant;
+        }
+
         @Override
         public void setTradingPlayer(EntityHuman entityhuman) {
             this.tradingPlayer = entityhuman;