From 6ba64cc39106857678b7b34954a3d7df3faa2c26 Mon Sep 17 00:00:00 2001
From: Brianna <bri@songoda.com>
Date: Sat, 14 Dec 2019 18:46:57 -0500
Subject: [PATCH] Added support for disabling knockback on stacked mobs.

---
 .../listeners/EntityListeners.java            | 18 +++++++++++++++++-
 .../ultimatestacker/settings/Settings.java    |  3 +++
 .../ultimatestacker/utils/EntityUtils.java    | 19 ++++++++++++++-----
 3 files changed, 34 insertions(+), 6 deletions(-)

diff --git a/src/main/java/com/songoda/ultimatestacker/listeners/EntityListeners.java b/src/main/java/com/songoda/ultimatestacker/listeners/EntityListeners.java
index d23ccb6..8af7652 100644
--- a/src/main/java/com/songoda/ultimatestacker/listeners/EntityListeners.java
+++ b/src/main/java/com/songoda/ultimatestacker/listeners/EntityListeners.java
@@ -12,20 +12,22 @@ import org.bukkit.Location;
 import org.bukkit.Material;
 import org.bukkit.block.Block;
 import org.bukkit.block.CreatureSpawner;
+import org.bukkit.enchantments.Enchantment;
 import org.bukkit.entity.*;
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.EventPriority;
 import org.bukkit.event.Listener;
 import org.bukkit.event.entity.CreatureSpawnEvent;
+import org.bukkit.event.entity.EntityDamageByEntityEvent;
 import org.bukkit.event.entity.EntityExplodeEvent;
 import org.bukkit.event.entity.ItemSpawnEvent;
 import org.bukkit.inventory.ItemStack;
 import org.bukkit.metadata.FixedMetadataValue;
+import org.bukkit.util.Vector;
 
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
-import java.util.stream.Collectors;
 
 public class EntityListeners implements Listener {
 
@@ -77,6 +79,20 @@ public class EntityListeners implements Listener {
         event.getEntity().setItemStack(item);
     }
 
+    @EventHandler(priority = EventPriority.HIGHEST, ignoreCancelled = true)
+    public void onHurt(EntityDamageByEntityEvent event) {
+        if (!Settings.STACK_ENTITIES.getBoolean() || !(event.getDamager() instanceof Player)) return;
+
+        if (plugin.getEntityStackManager().isStacked(event.getEntity())
+                && Settings.DISABLE_KNOCKBACK.getBoolean()
+                && ((Player) event.getDamager()).getItemInHand().getEnchantmentLevel(Enchantment.KNOCKBACK) == 0) {
+            Bukkit.getScheduler().scheduleSyncDelayedTask(plugin, () -> {
+                event.getEntity().setVelocity(new Vector());
+            }, 0L);
+        }
+    }
+
+
     @EventHandler(priority = EventPriority.HIGHEST, ignoreCancelled = true)
     public void onBlow(EntityExplodeEvent event) {
         if (!plugin.spawnersEnabled()) return;
diff --git a/src/main/java/com/songoda/ultimatestacker/settings/Settings.java b/src/main/java/com/songoda/ultimatestacker/settings/Settings.java
index f2e50c1..c55e69a 100644
--- a/src/main/java/com/songoda/ultimatestacker/settings/Settings.java
+++ b/src/main/java/com/songoda/ultimatestacker/settings/Settings.java
@@ -163,6 +163,9 @@ public class Settings {
     public static final ConfigSetting REALISTIC_DAMAGE = new ConfigSetting(config, "Entities.Use Realistic Weapon Damage", true,
             "Should weapons take damage based on the amount of entites in the stack?");
 
+    public static final ConfigSetting DISABLE_KNOCKBACK = new ConfigSetting(config, "Entities.Disable Knockback", false,
+            "Should knockback be disabled on unstacked mobs?");
+
     public static final ConfigSetting STACK_ITEMS = new ConfigSetting(config, "Items.Enabled", true,
             "Should items be stacked?");
 
diff --git a/src/main/java/com/songoda/ultimatestacker/utils/EntityUtils.java b/src/main/java/com/songoda/ultimatestacker/utils/EntityUtils.java
index a8896e0..5751d04 100644
--- a/src/main/java/com/songoda/ultimatestacker/utils/EntityUtils.java
+++ b/src/main/java/com/songoda/ultimatestacker/utils/EntityUtils.java
@@ -5,7 +5,10 @@ import com.songoda.ultimatestacker.UltimateStacker;
 import com.songoda.ultimatestacker.entity.Check;
 import com.songoda.ultimatestacker.entity.EntityStack;
 import com.songoda.ultimatestacker.settings.Settings;
-import org.bukkit.*;
+import org.bukkit.Location;
+import org.bukkit.Material;
+import org.bukkit.World;
+import org.bukkit.enchantments.Enchantment;
 import org.bukkit.entity.*;
 
 import java.util.*;
@@ -34,8 +37,8 @@ public class EntityUtils {
         Set<CachedChunk> chunks = new HashSet<>();
         if (world == null) return chunks;
 
-        Chunk firstChunk = location.getChunk();
-        chunks.add(new CachedChunk(firstChunk));
+        CachedChunk firstChunk = new CachedChunk(location);
+        chunks.add(firstChunk);
 
         if (singleChunk) return chunks;
 
@@ -60,7 +63,7 @@ public class EntityUtils {
             if (cachedChunks.containsKey(chunk)) {
                 entityArray = cachedChunks.get(chunk);
             } else {
-                entityArray = chunk.getChunk().getEntities();
+                entityArray = chunk.getEntities();
                 cachedChunks.put(chunk, entityArray);
             }
             for (Entity e : entityArray) {
@@ -84,7 +87,13 @@ public class EntityUtils {
 
     public LivingEntity newEntity(LivingEntity toClone) {
         LivingEntity newEntity = (LivingEntity) toClone.getWorld().spawnEntity(toClone.getLocation(), toClone.getType());
-        newEntity.setVelocity(toClone.getVelocity());
+
+        Player player = toClone.getKiller();
+        if (player == null
+                || !Settings.DISABLE_KNOCKBACK.getBoolean()
+                || player.getItemInHand().getEnchantmentLevel(Enchantment.KNOCKBACK) != 0) {
+            newEntity.setVelocity(toClone.getVelocity());
+        }
 
         for (String checkStr : checks) {
             Check check = Check.valueOf(checkStr);