Add a Pre Event

src/main/java/kamkeel/npcs/controllers/data/attribute/tracker/AttributeRecalcEvent.java

@@ -5,24 +5,32 @@ import net.minecraft.entity.player.EntityPlayer;
 import java.util.ArrayList;
 import java.util.List;
 
-public class AttributeRecalcEvent {
-    private static final List<IAttributeRecalcListener> listeners = new ArrayList<>();
-
-    /**
-     * Allows other mods to register a listener that is called after attribute recalculation.
-     */
-    public static void registerListener(IAttributeRecalcListener listener) {
-        if (listener != null && !listeners.contains(listener)) {
-            listeners.add(listener);
-        }
+public final class AttributeRecalcEvent {
+    @FunctionalInterface
+    public interface PreListener {
+        void onPre(EntityPlayer player, PlayerAttributeTracker tracker);
     }
 
-    /**
-     * Posts an event to all registered listeners.
-     */
+    private static final List<PreListener> preListeners = new ArrayList<>();
+    private static final List<Listener> postListeners = new ArrayList<>();
+
+    public static void pre(EntityPlayer player, PlayerAttributeTracker tracker) {
+        for (PreListener l : preListeners) l.onPre(player, tracker);
+    }
+
+    @FunctionalInterface
+    public interface Listener {
+        void onPost(EntityPlayer player, PlayerAttributeTracker tracker);
+    }
+
+    public static void registerListener(Listener l) {
+        postListeners.add(l);
+    }
     public static void post(EntityPlayer player, PlayerAttributeTracker tracker) {
-        for (IAttributeRecalcListener listener : listeners) {
-            listener.onAttributesRecalculated(player, tracker);
-        }
+        for (Listener l : postListeners) l.onPost(player, tracker);
+    }
+
+    public static void registerPreListener(PreListener l) {
+        preListeners.add(l);
     }
 }

src/main/java/kamkeel/npcs/controllers/data/attribute/tracker/PlayerAttributeTracker.java

@@ -31,7 +31,7 @@ public class PlayerAttributeTracker implements IPlayerAttributes {
     public static UUID knockbackResUUID = UUID.fromString("b2f261e8-34f0-4140-9828-b56c1f6e0ff2");
 
     private final UUID playerId;
-    private PlayerAttributeMap playerAttributes = new PlayerAttributeMap();
+    public PlayerAttributeMap playerAttributes = new PlayerAttributeMap();
 
     public float extraHealth = 0;
     public float extraHealthBoost = 0;
@@ -61,6 +61,8 @@ public class PlayerAttributeTracker implements IPlayerAttributes {
         magicDefense.clear();
         magicResistance.clear();
         if (player != null) {
+            AttributeRecalcEvent.pre(player, this);
+
             // Update equipment tracker.
             PlayerEquipmentTracker currentEquip = new PlayerEquipmentTracker();
             currentEquip.updateFrom(player);