Basic villager trades

src/main/java/cn/nukkit/entity/passive/EntityVillager.java

@@ -1,13 +1,27 @@
 package cn.nukkit.entity.passive;
 
+import java.util.ArrayList;
+import java.util.List;
+
+import cn.nukkit.Player;
+import cn.nukkit.entity.Entity;
 import cn.nukkit.entity.EntityAgeable;
 import cn.nukkit.entity.EntityCreature;
+import cn.nukkit.inventory.Inventory;
+import cn.nukkit.inventory.InventoryHolder;
+import cn.nukkit.inventory.TradeInventory;
+import cn.nukkit.inventory.TradeInventoryRecipe;
+import cn.nukkit.item.Item;
 import cn.nukkit.level.format.FullChunk;
 import cn.nukkit.nbt.tag.CompoundTag;
+import cn.nukkit.nbt.tag.ListTag;
 
-public class EntityVillager extends EntityCreature implements EntityNPC, EntityAgeable {
+public class EntityVillager extends EntityCreature implements InventoryHolder, EntityNPC, EntityAgeable {
 
     public static final int NETWORK_ID = 115;
+    private TradeInventory inventory;
+    private List<TradeInventoryRecipe> recipes = new ArrayList<TradeInventoryRecipe>();
+    private int tradeTier = 0;
 
     public EntityVillager(FullChunk chunk, CompoundTag nbt) {
         super(chunk, nbt);
@@ -43,7 +57,54 @@ public String getName() {
     public void initEntity() {
         super.initEntity();
         this.setMaxHealth(20);
+        this.inventory = new TradeInventory(this);
+    }
+
+    public void setTradeTier(int tier) {
+        this.tradeTier = tier;
+    }
+
+    public int getTradeTier() {
+        return this.tradeTier;
+    }
+
+    @Override
+    public boolean onInteract(Player player, Item item) {
+        if(recipes.size() > 0) {
+            player.addWindow(this.getInventory());
+            return true;
+        }
+        return false;
     }
+
+    public void addTradeRcipe(TradeInventoryRecipe recipe) {
+        this.recipes.add(recipe);
+    }
+
+	public CompoundTag getOffers() {
+	    CompoundTag nbt = new CompoundTag();
+	    nbt.putList(recipesToNbt());
+	    nbt.putList(getTierExpRequirements());
+	    return nbt;
+	}
+
+	private ListTag<CompoundTag> recipesToNbt() {
+	    ListTag<CompoundTag> tag = new ListTag<CompoundTag>("Recipes");
+	    for(TradeInventoryRecipe recipe : this.recipes) {
+	        tag.add(recipe.toNBT());
+	    }
+	    return tag;
+	}
+
+	private ListTag<CompoundTag> getTierExpRequirements() {
+	    ListTag<CompoundTag> tag = new ListTag<CompoundTag>("TierExpRequirements");
+	    tag.add(new CompoundTag().putInt("0", 0));
+	    tag.add(new CompoundTag().putInt("1", 10));
+	    tag.add(new CompoundTag().putInt("2", 60));
+	    tag.add(new CompoundTag().putInt("3", 160));
+	    tag.add(new CompoundTag().putInt("4", 310));
+	    return tag;
+	}
 
     public boolean isBaby() {
         return this.getDataFlag(DATA_FLAGS, DATA_FLAG_BABY);
@@ -53,4 +114,9 @@ public void setBaby(boolean baby) {
         this.setDataFlag(DATA_FLAGS, DATA_FLAG_BABY, baby);
         this.setScale(baby ? 0.5f : 1);
     }
+
+	@Override
+	public Inventory getInventory() {
+		return this.inventory;
+	}
 }

src/main/java/cn/nukkit/inventory/InventoryType.java

@@ -23,7 +23,8 @@ public enum InventoryType {
     BEACON(1, "Beacon", 13),
     OFFHAND(1, "Offhand", -1),
     MINECART_CHEST(27, "Minecart with Chest", 0),
-    MINECART_HOPPER(5, "Minecart with Hopper", 8);
+    MINECART_HOPPER(5, "Minecart with Hopper", 8),
+    TRADING(3, "Villager Trade", 15);
 
     private final int size;
     private final String title;

src/main/java/cn/nukkit/inventory/TradeInventory.java

@@ -0,0 +1,54 @@
+package cn.nukkit.inventory;
+
+import java.io.IOException;
+import java.nio.ByteOrder;
+
+import cn.nukkit.Player;
+import cn.nukkit.entity.passive.EntityVillager;
+import cn.nukkit.item.Item;
+import cn.nukkit.nbt.NBTIO;
+import cn.nukkit.network.protocol.UpdateTradePacket;
+
+public class TradeInventory extends BaseInventory {
+
+	public TradeInventory(InventoryHolder holder) {
+		super(holder, InventoryType.TRADING);
+	}
+
+	public void onOpen(Player who) {
+		super.onOpen(who);
+
+		UpdateTradePacket pk = new UpdateTradePacket();
+		pk.windowId = (byte) who.getWindowId(this);
+		pk.windowType = (byte) InventoryType.TRADING.getNetworkType();
+		pk.isWilling = true;
+		pk.screen2 = true;
+		pk.trader = this.getHolder().getId();
+		pk.tradeTier = this.getHolder().getTradeTier();
+		pk.player = who.getId();
+		try {
+			pk.offers = NBTIO.write(this.getHolder().getOffers(),ByteOrder.LITTLE_ENDIAN);
+		} catch(IOException ex) {}
+
+		who.dataPacket(pk);
+	}
+
+	public void onClose(Player who) {
+		for(int i = 0; i <= 1; i++) {
+			Item item = getItem(i);
+			if(who.getInventory().canAddItem(item)) {
+				who.getInventory().addItem(item);
+			} else {
+				who.dropItem(item);
+			}
+			this.clear(i);
+		}
+
+		super.onClose(who);
+	}
+
+	public EntityVillager getHolder() {
+		return (EntityVillager) this.holder;
+	}
+
+}

src/main/java/cn/nukkit/inventory/TradeInventoryRecipe.java

@@ -0,0 +1,104 @@
+package cn.nukkit.inventory;
+
+import cn.nukkit.item.Item;
+import cn.nukkit.nbt.NBTIO;
+import cn.nukkit.nbt.tag.CompoundTag;
+import lombok.Getter;
+
+public class TradeInventoryRecipe {
+
+	public static int A_ITEM = 0;
+	public static int B_ITEM = 1;
+	@Getter
+	private Item sellItem;
+	@Getter
+	private Item buyItem;
+	@Getter
+	private Item secondBuyItem;
+
+	private int tier = -1;
+	private int maxUses = 999;
+	private int buyCountA = 0;
+	private int buyCountB = 0;
+	private int uses = 0;
+	private int demand = 0;
+	private int rewardsExp = 0;
+	private int traderExp = 0;
+	private float priceMultiplierA = 0F;
+	private float priceMultiplierB = 0F;
+
+
+	public TradeInventoryRecipe(Item sellItem, Item buyItem) {
+		this(sellItem, buyItem, Item.get(0));
+	}
+
+	public TradeInventoryRecipe(Item sellItem, Item buyItem, Item secondBuyItem) {
+		this.sellItem = sellItem;
+		this.buyItem = buyItem;
+		this.secondBuyItem = secondBuyItem;
+	}
+
+	public TradeInventoryRecipe setTier(int tier) {
+		this.tier = tier;
+		return this;
+	}
+
+	public TradeInventoryRecipe setMaxUses(int maxUses) {
+		this.maxUses = maxUses;
+		return this;
+	}
+
+	public TradeInventoryRecipe setBuyCount(int count, int type) {
+		switch(type) {
+		case 0:
+			this.buyCountA = count;
+			break;
+		case 1:
+			this.buyCountB = count;
+			break;
+		}
+		this.buyCountA = count;
+		return this;
+	}
+
+	public TradeInventoryRecipe setDemand(int demand) {
+		this.demand = demand;
+		return this;
+	}
+
+	public TradeInventoryRecipe setMultiplier(float multiplier, int type) {
+		switch(type) {
+		case 0:
+			this.priceMultiplierA = multiplier;
+			break;
+		case 1:
+			this.priceMultiplierB = multiplier;
+			break;
+		}
+		return this;
+	}
+
+	public TradeInventoryRecipe setRewardExp(int reward) {
+		this.rewardsExp = reward;
+		return this;
+	}
+
+	public CompoundTag toNBT() {
+		CompoundTag nbt = new CompoundTag();
+		nbt.putCompound("buyA", NBTIO.putItemHelper(buyItem, -1));
+		nbt.putCompound("buyB", NBTIO.putItemHelper(secondBuyItem,-1));
+		nbt.putCompound("sell", NBTIO.putItemHelper(sellItem, -1));
+		nbt.putInt("tier", tier);
+		nbt.putInt("buyCountA", buyCountA);
+		nbt.putInt("buyCountB", buyCountB);
+		nbt.putInt("uses", uses);
+		nbt.putInt("maxUses", maxUses);
+		nbt.putInt("rewardExp", rewardsExp);
+		nbt.putInt("demand", demand);
+		nbt.putInt("traderExp", traderExp);
+		nbt.putFloat("priceMultiplierA", priceMultiplierA);
+		nbt.putFloat("priceMultiplierB", priceMultiplierB);
+		return nbt;
+	}
+
+}