SPIGOT-355: API for Villager careers

By: Senmori <thesenmori@gmail.com>

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

@@ -1,6 +1,9 @@
 package org.bukkit.craftbukkit.entity;
 
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
+import javax.annotation.Nullable;
 import net.minecraft.server.EntityVillager;
 import org.apache.commons.lang.Validate;
 import org.bukkit.craftbukkit.CraftServer;
@@ -15,6 +18,7 @@ import org.bukkit.inventory.MerchantRecipe;
 
 public class CraftVillager extends CraftAgeable implements Villager, InventoryHolder {
 
+    private static final Map<Career, Integer> careerIDMap = new HashMap<>();
     private CraftMerchant merchant;
 
     public CraftVillager(CraftServer server, EntityVillager entity) {
@@ -45,6 +49,31 @@ public class CraftVillager extends CraftAgeable implements Villager, InventoryHo
         getHandle().setProfession(profession.ordinal() - 1);
     }
 
+    @Override
+    public Career getCareer() {
+        return getCareer(getProfession(), getHandle().bK);
+    }
+
+    @Override
+    public void setCareer(Career career) {
+        setCareer(career, true);
+    }
+
+    @Override
+    public void setCareer(Career career, boolean resetTrades) {
+        if (career == null) {
+            getHandle().bK = 0; // reset career
+        } else {
+            Validate.isTrue(career.getProfession() == getProfession(), "Career assignment mismatch. Found (" + getProfession() + ") Required (" + career.getProfession() + ")");
+            getHandle().bK = getCareerID(career);
+        }
+
+        if (resetTrades) {
+            getHandle().trades = null;
+            getHandle().dx();
+        }
+    }
+
     @Override
     public Inventory getInventory() {
         return new CraftInventory(getHandle().inventory);
@@ -98,4 +127,38 @@ public class CraftVillager extends CraftAgeable implements Villager, InventoryHo
     public void setRiches(int riches) {
         getHandle().riches = riches;
     }
+
+    @Nullable
+    private static Career getCareer(Profession profession, int id) {
+        Validate.isTrue(id > 0, "Career id must be greater than 0");
+
+        List<Career> careers = profession.getCareers();
+        for (Career c : careers) {
+            if (careerIDMap.containsKey(c) && careerIDMap.get(c) == id) {
+                return c;
+            }
+        }
+
+        return null;
+    }
+
+    private static int getCareerID(Career career) {
+        return careerIDMap.getOrDefault(career, 0);
+    }
+
+    static {
+        // build Career -> ID map
+        int id = 0;
+        for (Profession prof : Profession.values()) {
+            List<Career> careers = prof.getCareers();
+            if (!careers.isEmpty()) {
+                for (Career c : careers) {
+                    careerIDMap.put(c, ++id);
+                }
+            }
+
+            Validate.isTrue(id == careers.size(), "Career id registration mismatch");
+            id = 0;
+        }
+    }
 }