From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Yannick Lamprecht <yannicklamprecht@live.de>
Date: Wed, 30 Mar 2022 18:16:52 +0200
Subject: [PATCH] Player Entity Tracking Events


diff --git a/src/main/java/net/minecraft/server/level/ChunkMap.java b/src/main/java/net/minecraft/server/level/ChunkMap.java
index de19a5ea96fa38621513e970e04d153576f4f6ae..bff776f07bcc7841acc5757c1f53bde1812756c8 100644
--- a/src/main/java/net/minecraft/server/level/ChunkMap.java
+++ b/src/main/java/net/minecraft/server/level/ChunkMap.java
@@ -1762,7 +1762,11 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
                 // CraftBukkit end
                 if (flag) {
                     if (this.seenBy.add(player.connection)) {
+                        // Paper start - entity tracking events
+                        if (io.papermc.paper.event.player.PlayerTrackEntityEvent.getHandlerList().getRegisteredListeners().length == 0 || new io.papermc.paper.event.player.PlayerTrackEntityEvent(player.getBukkitEntity(), this.entity.getBukkitEntity()).callEvent()) {
                         this.serverEntity.addPairing(player);
+                        }
+                        // Paper end - entity tracking events
                     }
                 } else if (this.seenBy.remove(player.connection)) {
                     this.serverEntity.removePairing(player);
diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
index 6fefd0e1dd2601914b2790469bfcbd04cd9b1a28..b2dad4867371f4976ceb6a6a2129b314e02f50aa 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -3858,7 +3858,14 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
 
     public void startSeenByPlayer(ServerPlayer player) {}
 
-    public void stopSeenByPlayer(ServerPlayer player) {}
+    // Paper start - entity tracking events
+    public void stopSeenByPlayer(ServerPlayer player) {
+        // Since this event cannot be cancelled, we should call it here to catch all "un-tracks"
+        if (io.papermc.paper.event.player.PlayerUntrackEntityEvent.getHandlerList().getRegisteredListeners().length > 0) {
+            new io.papermc.paper.event.player.PlayerUntrackEntityEvent(player.getBukkitEntity(), this.getBukkitEntity()).callEvent();
+        }
+    }
+    // Paper end - entity tracking events
 
     public float rotate(Rotation rotation) {
         float f = Mth.wrapDegrees(this.getYRot());