From be153d8ac65a7248333539c92f98844b979d048f Mon Sep 17 00:00:00 2001
From: libraryaddict <github@lib.co.nz>
Date: Thu, 8 Nov 2018 21:09:47 +1300
Subject: [PATCH] Add UUID version changing to support Chinese servers

---
 .../disguise/DisguiseConfig.java              | 10 ++++++
 .../disguise/utilities/ReflectionManager.java | 33 +++++++++++++++++--
 src/main/resources/config.yml                 |  6 +++-
 3 files changed, 45 insertions(+), 4 deletions(-)

diff --git a/src/main/java/me/libraryaddict/disguise/DisguiseConfig.java b/src/main/java/me/libraryaddict/disguise/DisguiseConfig.java
index 2e14d8ee..1bb8799d 100644
--- a/src/main/java/me/libraryaddict/disguise/DisguiseConfig.java
+++ b/src/main/java/me/libraryaddict/disguise/DisguiseConfig.java
@@ -68,6 +68,15 @@ public class DisguiseConfig {
     private static boolean warnScoreboardConflict;
     private static boolean explicitDisguisePermissions;
     private static boolean disableCommands;
+    private static int uuidGeneratedVersion;
+
+    public static int getUUIDGeneratedVersion() {
+        return uuidGeneratedVersion;
+    }
+
+    public static void setUUIDGeneratedVersion(int uuidVersion) {
+        uuidGeneratedVersion = uuidVersion;
+    }
 
     /**
      * No setter provided as this cannot be changed after startup
@@ -245,6 +254,7 @@ public class DisguiseConfig {
         setWarnScoreboardConflict(config.getBoolean("Scoreboard.WarnConflict"));
         disableCommands = config.getBoolean("DisableCommands");
         setExplicitDisguisePermissions(config.getBoolean("Permissions.ExplictDisguises"));
+        setUUIDGeneratedVersion(config.getInt("UUIDVersion"));
 
         if (!LibsPremium.isPremium() && (isSavePlayerDisguises() || isSaveEntityDisguises())) {
             DisguiseUtilities.getLogger().warning("You must purchase the plugin to use saved disguises!");
diff --git a/src/main/java/me/libraryaddict/disguise/utilities/ReflectionManager.java b/src/main/java/me/libraryaddict/disguise/utilities/ReflectionManager.java
index e246130c..7e01a0b2 100644
--- a/src/main/java/me/libraryaddict/disguise/utilities/ReflectionManager.java
+++ b/src/main/java/me/libraryaddict/disguise/utilities/ReflectionManager.java
@@ -6,6 +6,7 @@ import com.comphenix.protocol.wrappers.WrappedDataWatcher.Registry;
 import com.comphenix.protocol.wrappers.WrappedDataWatcher.Serializer;
 import com.comphenix.protocol.wrappers.WrappedDataWatcher.WrappedDataWatcherObject;
 import com.comphenix.protocol.wrappers.nbt.NbtWrapper;
+import me.libraryaddict.disguise.DisguiseConfig;
 import me.libraryaddict.disguise.disguisetypes.DisguiseType;
 import org.bukkit.*;
 import org.bukkit.entity.*;
@@ -14,6 +15,7 @@ import org.bukkit.inventory.ItemStack;
 import org.bukkit.potion.PotionEffect;
 
 import java.lang.reflect.*;
+import java.nio.ByteBuffer;
 import java.util.Optional;
 import java.util.UUID;
 
@@ -384,7 +386,7 @@ public class ReflectionManager {
 
     public static WrappedGameProfile getGameProfile(UUID uuid, String playerName) {
         try {
-            return new WrappedGameProfile(uuid != null ? uuid : UUID.randomUUID(), playerName);
+            return new WrappedGameProfile(uuid != null ? uuid : getRandomUUID(), playerName);
         }
         catch (Exception ex) {
             ex.printStackTrace();
@@ -399,8 +401,7 @@ public class ReflectionManager {
     public static WrappedGameProfile getGameProfileWithThisSkin(UUID uuid, String playerName,
             WrappedGameProfile profileWithSkin) {
         try {
-            WrappedGameProfile gameProfile = new WrappedGameProfile(uuid != null ? uuid : UUID.randomUUID(),
-                    playerName);
+            WrappedGameProfile gameProfile = new WrappedGameProfile(uuid != null ? uuid : getRandomUUID(), playerName);
 
             if (profileWithSkin != null) {
                 gameProfile.getProperties().putAll(profileWithSkin.getProperties());
@@ -415,6 +416,32 @@ public class ReflectionManager {
         return null;
     }
 
+    /**
+     * Used for generating a UUID with a custom version instead of the default 4. Workaround for China's NetEase servers
+     */
+    private static UUID getRandomUUID() {
+        UUID uuid = UUID.randomUUID();
+
+        if (DisguiseConfig.getUUIDGeneratedVersion() == 4) {
+            return uuid;
+        }
+
+        ByteBuffer bb = ByteBuffer.wrap(new byte[16]);
+
+        bb.putLong(uuid.getMostSignificantBits());
+        bb.putLong(uuid.getLeastSignificantBits());
+
+        bb.put(6, (byte) (bb.get(6) & 0x0f));  // clear version
+        bb.put(6, (byte) (bb.get(6) | DisguiseConfig.getUUIDGeneratedVersion()));  // set to version X (Default 4)
+
+        bb.position(0);
+
+        long firstLong = bb.getLong();
+        long secondLong = bb.getLong();
+
+        return new UUID(firstLong, secondLong);
+    }
+
     public static Class getNmsClass(String className) {
         try {
             return Class.forName("net.minecraft.server." + getBukkitVersion() + "." + className);
diff --git a/src/main/resources/config.yml b/src/main/resources/config.yml
index cbe7bb59..01b03df3 100644
--- a/src/main/resources/config.yml
+++ b/src/main/resources/config.yml
@@ -213,4 +213,8 @@ PacketsEnabled:
   # Disable this if you don't mind crashing everytime you see someone riding something disguised as a non-living entity
   Riding: true
   # When disguised as a wither skull, it sends a look packet every tick so that the wither skull is facing the right way.
-  WitherSkull: true
\ No newline at end of file
+  WitherSkull: true
+
+# Added to support a Chinese Minecraft Server which uses their own skin server unless the UUID is not version 4.
+# Changing this from 4 to say, 3. Means their server will fetch skins from Mojang instead.
+UUIDVersion: 4
\ No newline at end of file