Implement convert gem handler

src/main/java/emu/nebula/GameConstants.java

@@ -13,7 +13,9 @@ public class GameConstants {
     public static final int INTRO_GUIDE_ID = 1;
 
     public static final int GOLD_ITEM_ID = 1;
-    public static final int ENERGY_BUY_ITEM_ID = 2;
+    public static final int GEM_ITEM_ID = 2;
+    public static final int PREM_GEM_ITEM_ID = 3;
+    public static final int ENERGY_BUY_ITEM_ID = GEM_ITEM_ID;
     public static final int STAR_TOWER_GOLD_ITEM_ID = 11;
     public static final int EXP_ITEM_ID = 21;
     

src/main/java/emu/nebula/game/inventory/Inventory.java

@@ -790,6 +790,23 @@ public class Inventory extends PlayerManager implements GameDatabaseObject {
         return change.setSuccess(true);
     }
     
+    public PlayerChangeInfo convertGems(int amount) {
+        // Verify that we have the gems
+        if (!this.hasItem(GameConstants.PREM_GEM_ITEM_ID, amount)) {
+            return null;
+        }
+        
+        // Create change info
+        var change = new PlayerChangeInfo();
+        
+        // Convert gems
+        this.removeItem(GameConstants.PREM_GEM_ITEM_ID, amount, change);
+        this.addItem(GameConstants.GEM_ITEM_ID, amount, change);
+        
+        // Success
+        return change.setSuccess(true);
+    }
+    
     // Database
     
     public void loadFromDatabase() {

src/main/java/emu/nebula/server/handlers/HandlerGemConvertReq.java

@@ -0,0 +1,28 @@
+package emu.nebula.server.handlers;
+
+import emu.nebula.net.NetHandler;
+import emu.nebula.net.NetMsgId;
+import emu.nebula.proto.Public.UI32;
+import emu.nebula.net.HandlerId;
+import emu.nebula.net.GameSession;
+
+@HandlerId(NetMsgId.gem_convert_req)
+public class HandlerGemConvertReq extends NetHandler {
+
+    @Override
+    public byte[] handle(GameSession session, byte[] message) throws Exception {
+        // Parse request
+        var req = UI32.parseFrom(message);
+        
+        // Convert gems
+        var change = session.getPlayer().getInventory().convertGems(req.getValue());
+        
+        if (change == null) {
+            return session.encodeMsg(NetMsgId.gem_convert_failed_ack);
+        }
+        
+        // Encode and send
+        return session.encodeMsg(NetMsgId.gem_convert_succeed_ack, change.toProto());
+    }
+
+}