Implemented a generic proxy for dealing with different logical sides.

src/main/java/dev/micle/loginprotection/LoginProtection.java

@@ -1,10 +1,9 @@
 package dev.micle.loginprotection;
 
-import dev.micle.loginprotection.data.ProtectedPlayers;
-import dev.micle.loginprotection.setup.Config;
-import dev.micle.loginprotection.setup.Registration;
+import dev.micle.loginprotection.proxy.IProxy;
+import dev.micle.loginprotection.proxy.Proxy;
 import net.minecraft.resources.ResourceLocation;
-import net.minecraftforge.common.MinecraftForge;
+import net.minecraftforge.fml.DistExecutor;
 import net.minecraftforge.fml.common.Mod;
 import net.minecraftforge.network.NetworkRegistry;
 import net.minecraftforge.network.simple.SimpleChannel;
@@ -21,11 +20,16 @@ public class LoginProtection {
             PROTOCOL_VERSION::equals,
             PROTOCOL_VERSION::equals
     );
+    private static IProxy proxy;
 
     public LoginProtection() {
-        Registration.register();
-        Config.init();
+        proxy = DistExecutor.safeRunForDist(
+                () -> Proxy.Client::new,
+                () -> Proxy.Server::new
+        );
+    }
 
-        MinecraftForge.EVENT_BUS.register(this);
+    public static IProxy getProxy() {
+        return proxy;
     }
 }

src/main/java/dev/micle/loginprotection/proxy/IProxy.java

@@ -0,0 +1,11 @@
+package dev.micle.loginprotection.proxy;
+
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.level.Level;
+
+public interface IProxy {
+    MinecraftServer getServer();
+    Player getClientPlayer();
+    Level getClientWorld();
+}

src/main/java/dev/micle/loginprotection/proxy/Proxy.java

@@ -0,0 +1,112 @@
+package dev.micle.loginprotection.proxy;
+
+import dev.micle.loginprotection.data.ProtectedPlayerManager;
+import dev.micle.loginprotection.setup.Config;
+import dev.micle.loginprotection.setup.Registration;
+import net.minecraft.client.Minecraft;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.level.Level;
+import net.minecraftforge.api.distmarker.Dist;
+import net.minecraftforge.api.distmarker.OnlyIn;
+import net.minecraftforge.common.MinecraftForge;
+import net.minecraftforge.event.AddReloadListenerEvent;
+import net.minecraftforge.event.server.ServerStartedEvent;
+import net.minecraftforge.event.server.ServerStoppingEvent;
+import net.minecraftforge.eventbus.api.IEventBus;
+import net.minecraftforge.fml.event.lifecycle.*;
+import net.minecraftforge.fml.javafmlmod.FMLJavaModLoadingContext;
+
+public class Proxy implements IProxy {
+    // Initialize variables
+    private static MinecraftServer server = null;
+
+    // Common setup
+    public Proxy() {
+        // Initialize setup
+        Registration.register();
+        Config.init();
+
+        // Initialize other
+        ProtectedPlayerManager.init();
+
+        // Register mod event bus listeners
+        IEventBus modEventBus = FMLJavaModLoadingContext.get().getModEventBus();
+        modEventBus.addListener(Proxy::setup);
+        modEventBus.addListener(Proxy::imcEnqueue);
+        modEventBus.addListener(Proxy::imcProcess);
+
+        // Register event but listeners
+        MinecraftForge.EVENT_BUS.addListener(Proxy::onAddReloadListeners);
+        MinecraftForge.EVENT_BUS.addListener(Proxy::serverStarted);
+        MinecraftForge.EVENT_BUS.addListener(Proxy::serverStopping);
+    }
+
+    private static void setup(FMLCommonSetupEvent event) {}
+
+    private static void imcEnqueue(InterModEnqueueEvent event) {}
+
+    private static void imcProcess(InterModProcessEvent event) {}
+
+    private static void onAddReloadListeners(AddReloadListenerEvent event) {}
+
+    private static void serverStarted(ServerStartedEvent event) {
+        server = event.getServer();
+    }
+
+    private static void serverStopping(ServerStoppingEvent event) {
+        server = null;
+    }
+
+    @Override
+    public MinecraftServer getServer() {
+        return server;
+    }
+
+    @Override
+    public Player getClientPlayer() {
+        return null;
+    }
+
+    @Override
+    public Level getClientWorld() {
+        return null;
+    }
+
+    // Client setup
+    public static class Client extends Proxy {
+        public Client() {
+            // Register mod event bus listeners
+            IEventBus modEventBus = FMLJavaModLoadingContext.get().getModEventBus();
+            modEventBus.addListener(Client::setup);
+            modEventBus.addListener(Client::postSetup);
+        }
+
+        private static void setup(FMLClientSetupEvent event) {}
+
+        private static void postSetup(FMLLoadCompleteEvent event) {}
+
+        @Override
+        @OnlyIn(Dist.CLIENT)
+        public Player getClientPlayer() {
+            return Minecraft.getInstance().player;
+        }
+
+        @Override
+        @OnlyIn(Dist.DEDICATED_SERVER)
+        public Level getClientWorld() {
+            return Minecraft.getInstance().level;
+        }
+    }
+
+    // Server setup
+    public static class Server extends Proxy {
+        public Server() {
+            // Register mod event bus listeners
+            IEventBus modEventBus = FMLJavaModLoadingContext.get().getModEventBus();
+            modEventBus.addListener(Server::setup);
+        }
+
+        private static void setup(FMLDedicatedServerSetupEvent event) {}
+    }
+}