Allow servers to control the mod

src/main/java/de/guntram/mcmod/antighost/AGMode.java

@@ -0,0 +1,22 @@
+package de.guntram.mcmod.antighost;
+
+/**
+ * AntiGhost current mode.
+ *
+ * @author VidTu
+ */
+public enum AGMode {
+    /**
+     * The mod is enabled.
+     * Default state.
+     */
+    ENABLED,
+    /**
+     * The mod is disabled.
+     */
+    DISABLED,
+    /**
+     * The mod is enabled, but will use custom packets for requesting blocks.
+     */
+    CUSTOM;
+}

src/main/java/de/guntram/mcmod/antighost/AntiGhost.java

@@ -1,25 +1,33 @@
 package de.guntram.mcmod.antighost;
 
 import de.guntram.mcmod.crowdintranslate.CrowdinTranslate;
+import io.netty.buffer.Unpooled;
 import net.fabricmc.api.ClientModInitializer;
 import net.fabricmc.fabric.api.client.command.v2.ClientCommandManager;
 import net.fabricmc.fabric.api.client.command.v2.ClientCommandRegistrationCallback;
 import net.fabricmc.fabric.api.client.event.lifecycle.v1.ClientTickEvents;
 import net.fabricmc.fabric.api.client.keybinding.v1.KeyBindingHelper;
+import net.fabricmc.fabric.api.client.networking.v1.ClientPlayConnectionEvents;
+import net.fabricmc.fabric.api.client.networking.v1.ClientPlayNetworking;
 import net.minecraft.client.MinecraftClient;
 import net.minecraft.client.network.ClientPlayNetworkHandler;
 import net.minecraft.client.network.ClientPlayerEntity;
 import net.minecraft.client.option.KeyBinding;
+import net.minecraft.network.PacketByteBuf;
+import net.minecraft.network.packet.c2s.play.CustomPayloadC2SPacket;
 import net.minecraft.network.packet.c2s.play.PlayerActionC2SPacket;
 import net.minecraft.text.Text;
+import net.minecraft.util.Identifier;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.Direction;
 import static org.lwjgl.glfw.GLFW.GLFW_KEY_G;
 
 public class AntiGhost implements ClientModInitializer
 {
+    private static final Identifier CHANNEL = new Identifier("antighost", "v1");
     static final String MODID="antighost";
     static KeyBinding requestBlocks;
+    static AGMode mode;
 
     @Override
     public void onInitializeClient()
@@ -37,6 +45,11 @@ public void onInitializeClient()
                 })
             );
         });
+        ClientPlayNetworking.registerGlobalReceiver(CHANNEL, (client, handler, buf, responseSender) -> {
+            mode = buf.readEnumConstant(AGMode.class);
+        });
+        ClientPlayConnectionEvents.JOIN.register((handler, sender, client) -> mode = AGMode.ENABLED);
+        ClientPlayConnectionEvents.DISCONNECT.register((handler, client) -> mode = AGMode.ENABLED);
     }
 
     public void keyPressed() {
@@ -46,22 +59,37 @@ public void keyPressed() {
             player.sendMessage(Text.translatable("msg.request"), false);
         }
     }
-    
+
     public void execute() {
-        MinecraftClient mc=MinecraftClient.getInstance();
+        MinecraftClient mc = MinecraftClient.getInstance();
         ClientPlayNetworkHandler conn = mc.getNetworkHandler();
-        if (conn==null)
+        if (conn == null || mc.player == null) {
             return;
-        BlockPos pos=mc.player.getBlockPos();
-        for (int dx=-4; dx<=4; dx++)
-            for (int dy=-4; dy<=4; dy++)
-                for (int dz=-4; dz<=4; dz++) {
-                    PlayerActionC2SPacket packet=new PlayerActionC2SPacket(
-                            PlayerActionC2SPacket.Action.ABORT_DESTROY_BLOCK, 
-                            new BlockPos(pos.getX()+dx, pos.getY()+dy, pos.getZ()+dz),
-                            Direction.UP       // with ABORT_DESTROY_BLOCK, this value is unused
-                    );
-                    conn.sendPacket(packet);
+        }
+        switch (mode) {
+            case ENABLED -> {
+                BlockPos pos = mc.player.getBlockPos();
+                for (int dx = -4; dx <= 4; dx++) {
+                    for (int dy = -4; dy <= 4; dy++) {
+                        for (int dz = -4; dz <= 4; dz++) {
+                            PlayerActionC2SPacket packet = new PlayerActionC2SPacket(
+                                    PlayerActionC2SPacket.Action.ABORT_DESTROY_BLOCK,
+                                    new BlockPos(pos.getX() + dx, pos.getY() + dy, pos.getZ() + dz),
+                                    Direction.UP       // with ABORT_DESTROY_BLOCK, this value is unused
+                            );
+                            conn.sendPacket(packet);
+                        }
+                    }
                 }
+            }
+            case CUSTOM -> {
+                // Send a custom packet
+                conn.sendPacket(new CustomPayloadC2SPacket(CHANNEL, new PacketByteBuf(Unpooled.EMPTY_BUFFER)));
+            }
+            case DISABLED -> {
+                // Do nothing
+            }
+        }
+
     }
 }