Implement proper melody drops in Monolith

src/main/java/emu/nebula/data/resources/StarTowerDef.java

@@ -4,6 +4,7 @@ import java.util.Arrays;
 
 import emu.nebula.data.BaseDef;
 import emu.nebula.data.ResourceType;
+
 import lombok.Getter;
 
 @Getter
@@ -12,6 +13,7 @@ public class StarTowerDef extends BaseDef {
     private int Id;
     private int GroupId;
     private int Difficulty;
+    private int SubNoteSkillDropGroupId;
     private int[] FloorNum;
     
     private transient int maxFloors;

src/main/java/emu/nebula/data/resources/SubNoteSkillDropGroupDef.java

@@ -0,0 +1,45 @@
+package emu.nebula.data.resources;
+
+import emu.nebula.data.BaseDef;
+import emu.nebula.data.ResourceType;
+import emu.nebula.util.Utils;
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
+import it.unimi.dsi.fastutil.ints.IntArrayList;
+import it.unimi.dsi.fastutil.ints.IntList;
+import lombok.Getter;
+
+@Getter
+@ResourceType(name = "SubNoteSkillDropGroup.json")
+public class SubNoteSkillDropGroupDef extends BaseDef {
+    private int Id;
+    private int GroupId;
+    private int SubNoteSkillId;
+    
+    private static Int2ObjectMap<IntList> GROUPS = new Int2ObjectOpenHashMap<>();
+    
+    @Override
+    public int getId() {
+        return Id;
+    }
+    
+    @Override
+    public void onLoad() {
+        var packageList = GROUPS.computeIfAbsent(this.GroupId, i -> new IntArrayList());
+        packageList.add(this.SubNoteSkillId);
+    }
+    
+    public static int getRandomDrop(int groupId) {
+        var dropList = GROUPS.get(groupId);
+        
+        if (dropList == null) {
+            return 0;
+        }
+        
+        return Utils.randomElement(dropList);
+    }
+
+    public static IntList getGroup(int groupId) {
+        return GROUPS.get(groupId);
+    }
+}