From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Mon, 28 Mar 2016 21:22:26 -0400
Subject: [PATCH] EntityPathfindEvent

Fires when an Entity decides to start moving to a location.

diff --git a/src/main/java/net/minecraft/world/entity/ai/navigation/FlyingPathNavigation.java b/src/main/java/net/minecraft/world/entity/ai/navigation/FlyingPathNavigation.java
index 0af2c5dde41043a6fb2fcd07db96288c7f96e0c7..5e7e678c4469e34c7ae39656f547243fbcf1d0da 100644
--- a/src/main/java/net/minecraft/world/entity/ai/navigation/FlyingPathNavigation.java
+++ b/src/main/java/net/minecraft/world/entity/ai/navigation/FlyingPathNavigation.java
@@ -37,7 +37,7 @@ public class FlyingPathNavigation extends PathNavigation {
 
     @Override
     public Path createPath(Entity entity, int distance) {
-        return this.createPath(entity.blockPosition(), distance);
+        return this.a(entity.blockPosition(), entity, distance); // Paper - Forward target entity
     }
 
     @Override
diff --git a/src/main/java/net/minecraft/world/entity/ai/navigation/GroundPathNavigation.java b/src/main/java/net/minecraft/world/entity/ai/navigation/GroundPathNavigation.java
index cd7cb7cbe55a36282de394efc95f4ba7cc6a75cf..01be1de9d9ca0a86d69b2e82693bd0fea61a969f 100644
--- a/src/main/java/net/minecraft/world/entity/ai/navigation/GroundPathNavigation.java
+++ b/src/main/java/net/minecraft/world/entity/ai/navigation/GroundPathNavigation.java
@@ -75,7 +75,7 @@ public class GroundPathNavigation extends PathNavigation {
 
     @Override
     public Path createPath(Entity entity, int distance) {
-        return this.createPath(entity.blockPosition(), distance);
+        return this.a(entity.blockPosition(), entity, distance); // Paper - Forward target entity
     }
 
     private int getSurfaceY() {
diff --git a/src/main/java/net/minecraft/world/entity/ai/navigation/PathNavigation.java b/src/main/java/net/minecraft/world/entity/ai/navigation/PathNavigation.java
index 3cfd913e31236e35e7225ba19d292cacb8b4134a..ae8d430382b20ddd837c47e39515c7995f25312a 100644
--- a/src/main/java/net/minecraft/world/entity/ai/navigation/PathNavigation.java
+++ b/src/main/java/net/minecraft/world/entity/ai/navigation/PathNavigation.java
@@ -10,6 +10,7 @@ import net.minecraft.core.BlockPos;
 import net.minecraft.core.Position;
 import net.minecraft.core.Vec3i;
 import net.minecraft.network.protocol.game.DebugPackets;
+import net.minecraft.server.MCUtil;
 import net.minecraft.util.Mth;
 import net.minecraft.world.entity.Entity;
 import net.minecraft.world.entity.Mob;
@@ -28,7 +29,7 @@ import net.minecraft.world.phys.Vec3;
 
 public abstract class PathNavigation {
 
-    protected final Mob mob;
+    protected final Mob mob; public Entity getEntity() { return mob; } // Paper - OBFHELPER
     protected final Level level;
     @Nullable
     protected Path path;
@@ -115,36 +116,63 @@ public abstract class PathNavigation {
 
     @Nullable
     public Path createPath(BlockPos target, int distance) {
-        return this.createPath(ImmutableSet.of(target), 8, false, distance);
+        // Paper start - add target parameter
+        return this.a(target, null, distance);
+    }
+    @Nullable public Path a(BlockPos blockposition, Entity target, int i) {
+        return this.a(ImmutableSet.of(blockposition), target, 8, false, i);
+        // Paper end
     }
 
     @Nullable
     public Path createPath(Entity entity, int distance) {
-        return this.createPath(ImmutableSet.of(entity.blockPosition()), 16, true, distance);
+        return this.a(ImmutableSet.of(entity.blockPosition()), entity, 16, true, distance); // Paper
     }
 
     @Nullable
+    // Paper start - Add target
     protected Path createPath(Set<BlockPos> positions, int range, boolean flag, int distance) {
-        if (positions.isEmpty()) {
+        return this.a(positions, null, range, flag, distance);
+    }
+    @Nullable protected Path a(Set<BlockPos> set, Entity target, int i, boolean flag, int j) {
+        // Paper end
+        if (set.isEmpty()) {
             return null;
         } else if (this.mob.getY() < 0.0D) {
             return null;
         } else if (!this.canUpdatePath()) {
             return null;
-        } else if (this.path != null && !this.path.isDone() && positions.contains(this.targetPos)) {
+        } else if (this.path != null && !this.path.isDone() && set.contains(this.targetPos)) {
             return this.path;
         } else {
+            // Paper start - Pathfind event
+            boolean copiedSet = false;
+            for (BlockPos possibleTarget : set) {
+                if (!new com.destroystokyo.paper.event.entity.EntityPathfindEvent(getEntity().getBukkitEntity(),
+                    MCUtil.toLocation(getEntity().level, possibleTarget), target == null ? null : target.getBukkitEntity()).callEvent()) {
+                    if (!copiedSet) {
+                        copiedSet = true;
+                        set = new java.util.HashSet<>(set);
+                    }
+                    // note: since we copy the set this remove call is safe, since we're iterating over the old copy
+                    set.remove(possibleTarget);
+                    if (set.isEmpty()) {
+                        return null;
+                    }
+                }
+            }
+            // Paper end
             this.level.getProfiler().push("pathfind");
             float f = (float) this.mob.getAttributeValue(Attributes.FOLLOW_RANGE);
             BlockPos blockposition = flag ? this.mob.blockPosition().above() : this.mob.blockPosition();
-            int k = (int) (f + (float) range);
+            int k = (int) (f + (float) i);
             PathNavigationRegion chunkcache = new PathNavigationRegion(this.level, blockposition.offset(-k, -k, -k), blockposition.offset(k, k, k));
-            Path pathentity = this.pathFinder.findPath(chunkcache, this.mob, positions, f, distance, this.maxVisitedNodesMultiplier);
+            Path pathentity = this.pathFinder.findPath(chunkcache, this.mob, set, f, j, this.maxVisitedNodesMultiplier);
 
             this.level.getProfiler().pop();
             if (pathentity != null && pathentity.getTarget() != null) {
                 this.targetPos = pathentity.getTarget();
-                this.reachRange = distance;
+                this.reachRange = j;
                 this.resetStuckTimeout();
             }