From acb299530d112530fa61b46cec162f09c897ea4a Mon Sep 17 00:00:00 2001
From: s809 <43530948+s809@users.noreply.github.com>
Date: Fri, 14 Jun 2024 16:25:20 +0500
Subject: [PATCH] Avoid reloading levels when unnecessary

---
 .../api/internal/ClientPluginChannelApi.java  | 34 ++++++++++++++-----
 .../multiplayer/server/ServerPlayerState.java | 10 +++---
 2 files changed, 31 insertions(+), 13 deletions(-)

diff --git a/core/src/main/java/com/seibel/distanthorizons/core/api/internal/ClientPluginChannelApi.java b/core/src/main/java/com/seibel/distanthorizons/core/api/internal/ClientPluginChannelApi.java
index 7565f0b20..d3452ec37 100644
--- a/core/src/main/java/com/seibel/distanthorizons/core/api/internal/ClientPluginChannelApi.java
+++ b/core/src/main/java/com/seibel/distanthorizons/core/api/internal/ClientPluginChannelApi.java
@@ -55,25 +55,41 @@ public class ClientPluginChannelApi
 	
 	private void onCurrentLevelKeyMessage(CurrentLevelKeyMessage msg)
 	{
-		if (!msg.levelKey.matches("[a-zA-Z0-9_]+"))
+		if (!msg.levelKey.matches("[a-zA-Z0-9_]{1,50}"))
 		{
-			throw new IllegalArgumentException("Server sent invalid world key name.");
+			throw new IllegalArgumentException("Server sent invalid level key.");
 		}
 		
-		LOGGER.info("Server level change event received, changing the level to [" + msg.levelKey + "].");
+		LOGGER.info("Server level key received: " + msg.levelKey);
 		
 		MC.executeOnRenderThread(() -> {
 			IClientLevelWrapper clientLevel = MC.getWrappedClientLevel(true);
-			
-			if (clientLevel != null)
+			IServerKeyedClientLevel existingKeyedClientLevel = KEYED_CLIENT_LEVEL_MANAGER.getServerKeyedLevel();
+
+			if (existingKeyedClientLevel != null)
 			{
-				// In either case only one of them will have an effect.
+				if (!existingKeyedClientLevel.getServerLevelKey().equals(msg.levelKey))
+				{
+					LOGGER.info("Unloading previous level with key: " + existingKeyedClientLevel.getServerLevelKey());
+					this.levelUnloadHandler.accept(existingKeyedClientLevel);
+				}
+				else
+				{
+					LOGGER.info("Level key matches the previous level key, ignoring the message.");
+				}
+			}
+			else
+			{
+				LOGGER.info("Unloading non-keyed level: " + clientLevel.getDimensionType().getDimensionName());
 				this.levelUnloadHandler.accept(clientLevel);
-				this.levelUnloadHandler.accept(KEYED_CLIENT_LEVEL_MANAGER.getServerKeyedLevel());
 			}
 			
-			IServerKeyedClientLevel keyedLevel = KEYED_CLIENT_LEVEL_MANAGER.setServerKeyedLevel(clientLevel, msg.levelKey);
-			this.multiverseLevelLoadHandler.accept(keyedLevel);
+			if (existingKeyedClientLevel == null || !existingKeyedClientLevel.getServerLevelKey().equals(msg.levelKey))
+			{
+				LOGGER.info("Loading level with key: " + msg.levelKey);
+				IServerKeyedClientLevel keyedLevel = KEYED_CLIENT_LEVEL_MANAGER.setServerKeyedLevel(clientLevel, msg.levelKey);
+				this.multiverseLevelLoadHandler.accept(keyedLevel);
+			}
 		});
 	}
 	
diff --git a/core/src/main/java/com/seibel/distanthorizons/core/multiplayer/server/ServerPlayerState.java b/core/src/main/java/com/seibel/distanthorizons/core/multiplayer/server/ServerPlayerState.java
index f5e75a877..540624b34 100644
--- a/core/src/main/java/com/seibel/distanthorizons/core/multiplayer/server/ServerPlayerState.java
+++ b/core/src/main/java/com/seibel/distanthorizons/core/multiplayer/server/ServerPlayerState.java
@@ -1,8 +1,6 @@
 package com.seibel.distanthorizons.core.multiplayer.server;
 
-import com.seibel.distanthorizons.core.config.Config;
 import com.seibel.distanthorizons.core.level.DhServerLevel;
-import com.seibel.distanthorizons.core.logging.ConfigBasedLogger;
 import com.seibel.distanthorizons.core.multiplayer.config.MultiplayerConfig;
 import com.seibel.distanthorizons.core.multiplayer.config.MultiplayerConfigChangeListener;
 import com.seibel.distanthorizons.core.network.messages.plugin.CurrentLevelKeyMessage;
@@ -13,7 +11,6 @@ import com.seibel.distanthorizons.core.network.messages.plugin.fullData.FullData
 import com.seibel.distanthorizons.core.network.plugin.PluginChannelSession;
 import com.seibel.distanthorizons.core.util.ratelimiting.SupplierBasedRateAndConcurrencyLimiter;
 import com.seibel.distanthorizons.core.wrapperInterfaces.misc.IServerPlayerWrapper;
-import org.apache.logging.log4j.LogManager;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.concurrent.ConcurrentHashMap;
@@ -28,6 +25,7 @@ public class ServerPlayerState
 	@NotNull
 	public ConstrainedMultiplayerConfig config = new ConstrainedMultiplayerConfig();
 	private final MultiplayerConfigChangeListener configChangeListener = new MultiplayerConfigChangeListener(this::onConfigChanged);
+	private String lastLevelKey = "";
 	
 	private final ConcurrentHashMap<DhServerLevel, RateLimiterSet> rateLimiterSets = new ConcurrentHashMap<>();
 	public RateLimiterSet getRateLimiterSet(DhServerLevel level)
@@ -64,7 +62,11 @@ public class ServerPlayerState
 					levelKey = dimensionName;
 				}
 				
-				this.session.sendMessage(new CurrentLevelKeyMessage(levelKey));
+				if (!levelKey.equals(this.lastLevelKey))
+				{
+					this.lastLevelKey = levelKey;
+					this.session.sendMessage(new CurrentLevelKeyMessage(levelKey));
+				}
 			}
 			
 			this.session.sendMessage(new RemotePlayerConfigMessage(this.config));