From a99a36496ac48e239f5591a342e13dbac45a90f5 Mon Sep 17 00:00:00 2001
From: Micle <micle@micle.dev>
Date: Sun, 25 May 2025 00:24:13 +0100
Subject: [PATCH] Implemented logic for entity killing.

---
 .../OnLivingExperienceDropEventHandler.java   | 116 +++++++++++++++++-
 1 file changed, 115 insertions(+), 1 deletion(-)

diff --git a/src/main/java/dev/micle/xptools/events/common/OnLivingExperienceDropEventHandler.java b/src/main/java/dev/micle/xptools/events/common/OnLivingExperienceDropEventHandler.java
index 6cc7a23..f9d4a51 100644
--- a/src/main/java/dev/micle/xptools/events/common/OnLivingExperienceDropEventHandler.java
+++ b/src/main/java/dev/micle/xptools/events/common/OnLivingExperienceDropEventHandler.java
@@ -1,9 +1,123 @@
 package dev.micle.xptools.events.common;
 
+import dev.micle.xptools.XpTools;
+import dev.micle.xptools.config.Config;
+import dev.micle.xptools.operation.OperationCache;
+import dev.micle.xptools.operation.OperationItem;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.tags.TagKey;
+import net.minecraft.world.entity.EntityType;
 import net.minecraftforge.event.entity.living.LivingExperienceDropEvent;
 import net.minecraftforge.eventbus.api.SubscribeEvent;
+import net.minecraftforge.registries.ForgeRegistries;
+
+import java.time.Duration;
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+import java.util.concurrent.ThreadLocalRandom;
 
 public class OnLivingExperienceDropEventHandler {
     @SubscribeEvent
-    public void onLivingExperienceDropEvent(LivingExperienceDropEvent event) {}
+    public void onLivingExperienceDropEvent(LivingExperienceDropEvent event) {
+        Instant start = Instant.now();
+        float xpToDrop = event.getDroppedExperience();
+
+        // Get Entity id
+        ResourceLocation entity_rl = ForgeRegistries.ENTITY_TYPES.getKey(event.getEntity().getType());
+        String entity_id = "";
+        if (entity_rl != null) {
+            entity_id = entity_rl.toString();
+        }
+
+        // Collect operations
+        List<OperationItem> operations = null;
+        if (Config.Server.optimizationUseCache.get()) {
+            operations = OperationCache.getEntityKillCacheEntry(entity_id);
+        }
+
+        if (operations == null) {
+            operations = new ArrayList<>();
+
+            // Collect operations on relevant entity_id
+            if (!entity_id.isEmpty()) {
+                for (OperationItem operationItem : Config.Server.entityKillOperationItems) {
+                    if (!operationItem.isTag() && operationItem.getId().equals(entity_id)) {
+                        operations.add(operationItem);
+                    }
+                }
+            }
+
+            // Collect operations on relevant tag_id
+            for (TagKey<EntityType<?>> tagKey : event.getEntity().getType().getTags().toList()) {
+                String tag_id = tagKey.location().toString();
+                for (OperationItem operationItem : Config.Server.entityKillOperationItems) {
+                    if (operationItem.isTag() && operationItem.getId().equals(tag_id)) {
+                        operations.add(operationItem);
+                    }
+                }
+            }
+
+            // Sort operations based on priority
+            operations.sort(Comparator.comparingInt(OperationItem::getPriority));
+
+            // Remove any operations after last operation
+            for (OperationItem operationItem : operations) {
+                if (operationItem.isLast()) {
+                    operations = operations.subList(0, operations.indexOf(operationItem) + 1);
+                    break;
+                }
+            }
+
+            // Save operations to cache
+            OperationCache.addEntityKillCacheEntry(entity_id, operations);
+        }
+
+        // Add global operations before all others
+        operations.addAll(0, Config.Server.entityKillGlobalOperationItems);
+
+        // Apply operations to xp drops
+        for (OperationItem operation : operations) {
+            // Calculate operation value
+            float opValue = (operation.getMin() == operation.getMax()) ?
+                    operation.getMin() :
+                    ThreadLocalRandom.current().nextFloat(operation.getMin(), operation.getMax());
+
+            // Apply operation
+            switch (operation.getType()) {
+                case SET:
+                    xpToDrop = opValue;
+                    break;
+                case ADD:
+                    xpToDrop += opValue;
+                    break;
+                case SUBTRACT:
+                    xpToDrop -= opValue;
+                    break;
+                case MULTIPLY:
+                    xpToDrop *= opValue;
+                    break;
+                case DIVIDE:
+                    xpToDrop /= opValue;
+                    break;
+            }
+
+            // Stop if this is the last operation
+            if (operation.isLast()) {
+                break;
+            }
+        }
+
+        // Debug logging
+        if (Config.Server.debugExtra.get()) {
+            XpTools.LOGGER.debug("Completed entity kill event:");
+            XpTools.LOGGER.debug("\tOperations: {}", operations);
+            XpTools.LOGGER.debug("\tTime taken (nano seconds): {}", Duration.between(start, Instant.now()).toNanos());
+            XpTools.LOGGER.debug("\tXP: {} -> {}", event.getDroppedExperience(), xpToDrop);
+        }
+
+        // Apply xp drop
+        event.setDroppedExperience((int)xpToDrop);
+    }
 }