From 3bffdebd9210fa8a84f1f849d3b471aedfef1b65 Mon Sep 17 00:00:00 2001
From: Pablo Herrera <pabloherrerapalacio@gmail.com>
Date: Sun, 12 May 2024 17:09:09 +0200
Subject: [PATCH] Improve world border logic (#1314)

Signed-off-by: Pablo Herrera <pabloherrerapalacio@gmail.com>
---
 .../tc/oc/pgm/util/bukkit/WorldBorders.java   | 65 +++++++++++--------
 .../java/tc/oc/pgm/util/nms/NMSHacks.java     |  4 ++
 .../java/tc/oc/pgm/util/nms/NMSHacksNoOp.java |  5 ++
 .../tc/oc/pgm/util/nms/NMSHacksPlatform.java  |  2 +
 .../tc/oc/pgm/util/nms/v1_8/NMSHacks1_8.java  |  5 ++
 5 files changed, 54 insertions(+), 27 deletions(-)

diff --git a/util/src/main/java/tc/oc/pgm/util/bukkit/WorldBorders.java b/util/src/main/java/tc/oc/pgm/util/bukkit/WorldBorders.java
index dd79e85ea4..8e680355b9 100644
--- a/util/src/main/java/tc/oc/pgm/util/bukkit/WorldBorders.java
+++ b/util/src/main/java/tc/oc/pgm/util/bukkit/WorldBorders.java
@@ -1,49 +1,60 @@
 package tc.oc.pgm.util.bukkit;
 
 import org.bukkit.Location;
+import org.bukkit.World;
 import org.bukkit.WorldBorder;
+import org.bukkit.util.NumberConversions;
+import tc.oc.pgm.util.nms.NMSHacks;
 
-public interface WorldBorders {
+public class WorldBorders {
 
-  static boolean isInsideBorder(Location location) {
-    WorldBorder border = location.getWorld().getWorldBorder();
-    Location center = border.getCenter();
-    double radius = border.getSize() / 2d;
-    return Math.abs(location.getX() - center.getX()) < radius
-        && Math.abs(location.getZ() - center.getZ()) < radius;
+  private WorldBorders() {}
+
+  public static boolean isInsideBorder(Location location) {
+    BorderRect rect = new BorderRect(location.getWorld());
+    return location.getBlockX() >= rect.xMin
+        && location.getBlockX() <= rect.xMax
+        && location.getBlockZ() >= rect.zMin
+        && location.getBlockZ() <= rect.zMax;
   }
 
-  static boolean clampToBorder(Location location) {
-    WorldBorder border = location.getWorld().getWorldBorder();
-    Location center = border.getCenter();
-    double radius = border.getSize() / 2d;
-    double xMin = center.getX() - radius;
-    double xMax = center.getX() + radius;
-    double zMin = center.getZ() - radius;
-    double zMax = center.getZ() + radius;
+  public static boolean clampToBorder(Location location) {
+    BorderRect rect = new BorderRect(location.getWorld());
 
     boolean moved = false;
 
-    if (location.getX() < xMin) {
-      location.setX(xMin);
+    if (location.getX() <= rect.xMin) {
+      location.setX(rect.xMin + 0.5);
       moved = true;
-    }
-
-    if (location.getX() > xMax) {
-      location.setX(xMax);
+    } else if (location.getX() >= rect.xMax) {
+      location.setX(rect.xMax - 0.5);
       moved = true;
     }
 
-    if (location.getZ() < zMin) {
-      location.setZ(zMin);
+    if (location.getZ() <= rect.zMin) {
+      location.setZ(rect.zMin + 0.5);
       moved = true;
-    }
-
-    if (location.getZ() > zMax) {
-      location.setZ(zMax);
+    } else if (location.getZ() >= rect.zMax) {
+      location.setZ(rect.zMax - 0.5);
       moved = true;
     }
 
     return moved;
   }
+
+  private static class BorderRect {
+    public final int xMin, xMax, zMin, zMax;
+
+    public BorderRect(World world) {
+      WorldBorder border = world.getWorldBorder();
+      Location center = border.getCenter();
+      double radius = border.getSize() / 2d;
+      int maxWorldSize = NMSHacks.getMaxWorldSize(world);
+
+      xMin = Math.max(NumberConversions.floor(center.getX() - radius), -maxWorldSize);
+      xMax = Math.min(NumberConversions.ceil(center.getX() + radius), maxWorldSize);
+      zMin = Math.max(NumberConversions.floor(center.getZ() - radius), -maxWorldSize);
+      zMax = Math.min(NumberConversions.ceil(center.getZ() + radius), maxWorldSize);
+    }
+  }
 }
diff --git a/util/src/main/java/tc/oc/pgm/util/nms/NMSHacks.java b/util/src/main/java/tc/oc/pgm/util/nms/NMSHacks.java
index c145165b22..62fb0f28df 100644
--- a/util/src/main/java/tc/oc/pgm/util/nms/NMSHacks.java
+++ b/util/src/main/java/tc/oc/pgm/util/nms/NMSHacks.java
@@ -443,4 +443,8 @@ static AttributeMap buildAttributeMap(Player player) {
   static void postToMainThread(Plugin plugin, boolean priority, Runnable task) {
     INSTANCE.postToMainThread(plugin, priority, task);
   }
+
+  static int getMaxWorldSize(World world) {
+    return INSTANCE.getMaxWorldSize(world);
+  }
 }
diff --git a/util/src/main/java/tc/oc/pgm/util/nms/NMSHacksNoOp.java b/util/src/main/java/tc/oc/pgm/util/nms/NMSHacksNoOp.java
index 988b892cc2..01fda85384 100644
--- a/util/src/main/java/tc/oc/pgm/util/nms/NMSHacksNoOp.java
+++ b/util/src/main/java/tc/oc/pgm/util/nms/NMSHacksNoOp.java
@@ -307,4 +307,9 @@ public void postToMainThread(Plugin plugin, boolean priority, Runnable task) {
     // runs the task on the next tick, not a perfect replacement
     plugin.getServer().getScheduler().runTask(plugin, task);
   }
+
+  @Override
+  public int getMaxWorldSize(World world) {
+    return 29999984; // Vanilla's default
+  }
 }
diff --git a/util/src/main/java/tc/oc/pgm/util/nms/NMSHacksPlatform.java b/util/src/main/java/tc/oc/pgm/util/nms/NMSHacksPlatform.java
index 056878f4fc..69d98fe9a1 100644
--- a/util/src/main/java/tc/oc/pgm/util/nms/NMSHacksPlatform.java
+++ b/util/src/main/java/tc/oc/pgm/util/nms/NMSHacksPlatform.java
@@ -210,4 +210,6 @@ Object teamPacket(
   AttributeMap buildAttributeMap(Player player);
 
   void postToMainThread(Plugin plugin, boolean priority, Runnable task);
+
+  int getMaxWorldSize(World world);
 }
diff --git a/util/src/main/java/tc/oc/pgm/util/nms/v1_8/NMSHacks1_8.java b/util/src/main/java/tc/oc/pgm/util/nms/v1_8/NMSHacks1_8.java
index c7199ae81d..5fc822bd7f 100644
--- a/util/src/main/java/tc/oc/pgm/util/nms/v1_8/NMSHacks1_8.java
+++ b/util/src/main/java/tc/oc/pgm/util/nms/v1_8/NMSHacks1_8.java
@@ -972,6 +972,11 @@ public double getTPS() {
     return 20.0;
   }
 
+  @Override
+  public int getMaxWorldSize(World world) {
+    return ((CraftWorld) world).getHandle().getWorldBorder().l();
+  }
+
   enum TeamPacketFields {
     a,
     b,