Fixed command dispatcher in MC 1.20.6

- Updated Internals class

 > Related to #125

Author: josemmo

src/main/java/io/josemmo/bukkit/plugin/utils/Internals.java

@@ -6,14 +6,15 @@
 import org.bukkit.command.CommandMap;
 import org.bukkit.command.CommandSender;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 
 public class Internals {
     public static final float MINECRAFT_VERSION;
     private static final CommandDispatcher<?> DISPATCHER;
     private static final CommandMap COMMAND_MAP;
-    private static final Method GET_BUKKIT_SENDER_METHOD;
+    private static @Nullable Method GET_BUKKIT_SENDER_METHOD = null;
 
     static {
         try {
@@ -30,24 +31,30 @@ public class Internals {
             Object nmsInstance = obcClass.getDeclaredMethod("getServer").invoke(obcInstance);
             Class<?> nmsClass = nmsInstance.getClass().getSuperclass();
 
-            // Get "net.minecraft.server.CommandDispatcher" references
-            Object nmsDispatcherInstance = nmsClass.getDeclaredField("vanillaCommandDispatcher").get(nmsInstance);
-            Class<?> nmsDispatcherClass = nmsDispatcherInstance.getClass();
+            if (MINECRAFT_VERSION >= 20.6) {
+                // Get "net.minecraft.commands.Commands" references
+                Object nmsCommandsInstance = nmsClass.getDeclaredMethod("getCommands").invoke(nmsInstance);
+                Class<?> nmsCommandsClass = nmsCommandsInstance.getClass();
 
-            // Get Brigadier dispatcher instance
-            Method getDispatcherMethod = nmsDispatcherClass.getDeclaredMethod("a");
-            getDispatcherMethod.setAccessible(true);
-            DISPATCHER = (CommandDispatcher<?>) getDispatcherMethod.invoke(nmsDispatcherInstance);
+                // Get "com.mojang.brigadier.CommandDispatcher" instance
+                Field nmsDispatcherField = nmsCommandsClass.getDeclaredField("dispatcher");
+                nmsDispatcherField.setAccessible(true);
+                DISPATCHER = (CommandDispatcher<?>) nmsDispatcherField.get(nmsCommandsInstance);
+            } else {
+                // Get "net.minecraft.server.CommandDispatcher" references
+                Object nmsDispatcherInstance = nmsClass.getDeclaredField("vanillaCommandDispatcher").get(nmsInstance);
+                Class<?> nmsDispatcherClass = nmsDispatcherInstance.getClass();
+
+                // Get "com.mojang.brigadier.CommandDispatcher" instance
+                Method getDispatcherMethod = nmsDispatcherClass.getDeclaredMethod("a");
+                getDispatcherMethod.setAccessible(true);
+                DISPATCHER = (CommandDispatcher<?>) getDispatcherMethod.invoke(nmsDispatcherInstance);
+            }
 
             // Get command map instance
             Field commandMapField = obcClass.getDeclaredField("commandMap");
             commandMapField.setAccessible(true);
             COMMAND_MAP = (CommandMap) commandMapField.get(obcInstance);
-
-            // Get CommandListenerWrapper.getBukkitSender() method
-            Class<?> clwClass = Class.forName(nmsDispatcherClass.getPackage().getName() + ".CommandListenerWrapper");
-            GET_BUKKIT_SENDER_METHOD = clwClass.getDeclaredMethod("getBukkitSender");
-            GET_BUKKIT_SENDER_METHOD.setAccessible(true);
         } catch (Exception e) {
             throw new RuntimeException("Failed to get internal classes due to incompatible Minecraft server", e);
         }
@@ -76,9 +83,12 @@ public class Internals {
      */
     public static @NotNull CommandSender getBukkitSender(@NotNull Object source) {
         try {
+            if (GET_BUKKIT_SENDER_METHOD == null) {
+                GET_BUKKIT_SENDER_METHOD = source.getClass().getDeclaredMethod("getBukkitSender");
+            }
             return (CommandSender) GET_BUKKIT_SENDER_METHOD.invoke(source);
         } catch (Exception e) {
-            throw new RuntimeException("Failed to extract bukkit sender from source", e);
+            throw new RuntimeException("Failed to extract Bukkit sender from source", e);
         }
     }
 }