Code Patterns

package dev.myplugin.example;

// import dev.myplugin.example.TroubleInTrorkTownPlugin;  // Anonymized
// import dev.myplugin.example.PlayerGameModeInfo;  // Anonymized
// import dev.myplugin.example.DoubleTapDetector;  // Anonymized
import com.hypixel.hytale.builtin.instances.InstancesPlugin;
import com.hypixel.hytale.component.Ref;
import com.hypixel.hytale.logger.HytaleLogger;
import com.hypixel.hytale.math.vector.Transform;
import com.hypixel.hytale.server.core.HytaleServer;
import com.hypixel.hytale.server.core.Message;
import com.hypixel.hytale.server.core.command.system.CommandContext;
import com.hypixel.hytale.server.core.command.system.arguments.system.RequiredArg;
import com.hypixel.hytale.server.core.command.system.arguments.types.ArgTypes;
import com.hypixel.hytale.server.core.command.system.basecommands.CommandBase;
import com.hypixel.hytale.server.core.entity.entities.Player;
import com.hypixel.hytale.server.core.universe.PlayerRef;
import com.hypixel.hytale.server.core.universe.Universe;
import com.hypixel.hytale.server.core.universe.world.World;
import com.hypixel.hytale.server.core.universe.world.storage.EntityStore;
import org.checkerframework.checker.nullness.compatqual.NonNullDecl;

import java.util.UUID;
import java.util.concurrent.TimeUnit;

public class ExampleCommand extends CommandBase {

	private static final HytaleLogger LOGGER = HytaleLogger.forEnclosingClass();

	RequiredArg<String> targetWorld = this.withRequiredArg("targetWorld", "Target world name", ArgTypes.STRING);

	public ExampleCommand() {
		super("change-world", "Debug command to change the current world.");
	}

	/**
	 * Loads a new world instance and teleports all players from the current world to it.
	 * Note: This method does NOT check the transition flag - callers should use
	 * scheduleWorldTransition() from PlayerReadyEventListener to ensure proper timing.
	 *
	 * @param currentWorld The world to teleport players from
	 * @param newWorldName The name of the world template to spawn
	 */
	public static void loadInstance(World currentWorld, String newWorldName) {
		currentWorld.execute(() -> {
			TroubleInTrorkTownPlugin.currentInstance = newWorldName;

			// Store old world info before spawning new instance
			String oldWorldName = currentWorld.getName();
			UUID oldWorldUuid = currentWorld.getWorldConfig().getUuid();

			World targetWorld = null;
			try {
				targetWorld = InstancesPlugin.get()
						.spawnInstance(newWorldName, currentWorld, new Transform())
						.get();

			} catch (Exception e) {
				LOGGER.atSevere().withCause(e).log("Failed to spawn instance: " + newWorldName);
				throw new RuntimeException(e);
			}

			for (PlayerRef playerRef : currentWorld.getPlayerRefs()) {
				Ref<EntityStore> ref = playerRef.getReference();
				PlayerGameModeInfo playerInfo = ref.getStore().getComponent(ref, PlayerGameModeInfo.componentType);

				if (!ref.isValid()) {
					continue;
				}

				playerInfo.setWorldInstance(newWorldName);
				InstancesPlugin.teleportPlayerToInstance(
						ref,
						ref.getStore(),
						targetWorld,
						null
				);
			}

			// Clear all player states to prevent memory leak when changing instances
			DoubleTapDetector.getInstance().clearAllPlayers();

			// Clean up old GameModeState
			TroubleInTrorkTownPlugin.gameModeStateForWorld.remove(oldWorldUuid);

			// Clean up old GameModeState
			TroubleInTrorkTownPlugin.instanceConfig.remove(oldWorldName);

			// Schedule direct world removal after teleports complete (2 seconds delay)
			// Using Universe.removeWorld() directly instead of safeRemoveInstance() because
			// safeRemoveInstance() silently fails if the world has no InstanceWorldConfig
			HytaleServer.SCHEDULED_EXECUTOR.schedule(() -> {
				try {
					// Don't remove the default world!
					String defaultWorldName = HytaleServer.get().getConfig().getDefaults().getWorld();
					if (oldWorldName.equalsIgnoreCase(defaultWorldName)) {
						LOGGER.atInfo().log("Skipping removal of default world: " + oldWorldName);
						return;
					}

					World oldWorld = Universe.get().getWorld(oldWorldName);
					if (oldWorld != null && oldWorld.getPlayerCount() == 0) {
						LOGGER.atInfo().log("Removing old world instance: " + oldWorldName);
						Universe.get().removeWorld(oldWorldName);
					} else if (oldWorld != null) {
						LOGGER.atWarning().log("Cannot remove world %s - still has %d players",
								oldWorldName, oldWorld.getPlayerCount());
					}
				} catch (Exception e) {
					LOGGER.atWarning().withCause(e).log("Failed to remove old world: " + oldWorldName);
				}
			}, 2, TimeUnit.SECONDS);
		});
	}

	@Override
	protected void executeSync(@NonNullDecl CommandContext commandContext) {
		World originWorld = commandContext.senderAs(Player.class).getWorld();
		String[] targetWorldName = commandContext.getInput(targetWorld);

		if (targetWorldName.length != 1) {
			commandContext.sendMessage(Message.raw("You must specify a target world name."));
			return;
		}

		if (originWorld == null) {
			commandContext.sendMessage(Message.raw("You are not in a world."));
			return;
		}

		loadInstance(originWorld, targetWorldName[0]);
	}
}