use uuid of player for the folder

src/main/java/dev/jab125/hotjoin/HotJoin.java

@@ -23,6 +23,7 @@
 import net.minecraft.client.server.IntegratedServer;
 import org.apache.commons.io.file.PathUtils;
 import org.apache.commons.lang3.ArrayUtils;
+import org.jetbrains.annotations.Nullable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import wily.legacy.client.screen.Assort;
@@ -337,16 +338,17 @@ public static  <T, R extends Throwable> T crashgoByeBye(SupplierButBetter<T, R>
 	static int hotJoin(CommandContext<FabricClientCommandSource> a) {
 		HotJoin.canLaunchOtherwiseThrow();
 		try {
-			launchMinecraftClient(null, null, null);
+			launchMinecraftClient(null, null, null, null);
 		} catch (IOException e) {
 			throw new RuntimeException(e);
 		}
 		return 0;
 	}
 
 	// The goal is to launch Minecraft a second time, under a different directory.
-	public static UUID launchMinecraftClient(String compat, String magic, String legacy4jData) throws IOException {
+	public static UUID launchMinecraftClient(String compat, String magic, String legacy4jData, @Nullable String folderName) throws IOException {
 		HotJoin.canLaunchOtherwiseThrow();
+		if (folderName == null || folderName.isBlank()) folderName = "second";
 		if (magic != null) magic = magic.replace("=", "$");
 		if (legacy4jData != null) legacy4jData = legacy4jData.replace("=", "$");
 		UUID uuid = UUID.randomUUID();
@@ -362,9 +364,10 @@ public static UUID launchMinecraftClient(String compat, String magic, String leg
 			}
 			i++;
 		}
-		Path path = Path.of("second");
-		path.toFile().mkdirs();
-		transfer(path);
+		Path path = Path.of(".hotjoin-instances/" + folderName);
+		boolean directory = path.toFile().isDirectory();
+		if (!directory) path.toFile().mkdirs();
+		if (!directory) transfer(path);
 		launchArguments[i + 1] = path.toAbsolutePath().toString();
 		String cp = System.getProperty("java.class.path");
 		List<String> splitClassPath = Arrays.stream(cp.split(File.pathSeparator)).toList();

src/main/java/dev/jab125/hotjoin/api/HotJoinAccess.java

@@ -10,8 +10,12 @@ public static UUID launchMinecraftClient(String compat, String magic) {
 		return launchMinecraftClient(compat, magic, null);
 	}
 	public static <T extends Throwable> UUID launchMinecraftClient(String compat, String magic, @Nullable String legacy4jData) throws T {
+		return launchMinecraftClient(compat, magic, legacy4jData, null);
+	}
+
+	public static <T extends Throwable> UUID launchMinecraftClient(String compat, String magic, @Nullable String legacy4jData, @Nullable String folderName) throws T {
 		try {
-			return HotJoin.launchMinecraftClient(compat, magic, legacy4jData);
+			return HotJoin.launchMinecraftClient(compat, magic, legacy4jData, folderName);
 		} catch (Throwable t) {
 			throw (T) t;
 		}

src/main/java/dev/jab125/hotjoin/compat/authme/AuthMeCompat.java

@@ -22,8 +22,8 @@ public int hotJoinAuthMeMicrosoft(CommandContext<FabricClientCommandSource> a) {
 		return 0;
 	}
 
-	private static void launchAuthMeClient(String magic) {
-		HotJoinAccess.launchMinecraftClient("authme", magic);
+	private static void launchAuthMeClient(String uuid, String magic) {
+		HotJoinAccess.launchMinecraftClient("authme", magic, null, uuid);
 	}
 
 	@Override

src/main/java/dev/jab125/hotjoin/compat/legacy4j/Legacy4JModCompat.java

@@ -36,13 +36,14 @@
 import java.util.Base64;
 import java.util.HashMap;
 import java.util.UUID;
+import java.util.function.BiConsumer;
 import java.util.function.Consumer;
 
 import static dev.jab125.hotjoin.HotJoin.crashgoByeBye;
 
 public class Legacy4JModCompat implements ILegacy4JModCompat {
 	// used by MCAccountMixin due to the lack of mutable static fields in interfaces
-	public static Consumer<String> authConsumer;
+	public static BiConsumer<String, String> authConsumer;
 	public static final HashMap<UUID, Legacy4JData> uuidLegacy4JMap = new HashMap<>();
 	public Legacy4JModCompat() {
 		ScreenEvents.AFTER_INIT.register((client, screen, scaledWidth, scaledHeight) -> {
@@ -69,16 +70,16 @@ public static void openLegacy4JUserPicker() {
 	public static void openLegacy4JUserPicker(Legacy4JData data) {
 		if (data != null) ScreenUtil.getLegacyOptions().selectedController().set(data.controllerIndex());
 		ChooseUserScreen chooseUserScreen = new ChooseUserScreen(null);
-		((AuthCallback)chooseUserScreen).hotjoin$authResponse(s -> {
+		((AuthCallback)chooseUserScreen).hotjoin$authResponse((uuid, s) -> {
 			Minecraft.getInstance().getToasts().addToast(new LegacyTip(Component.literal("Success, joining world...")));
-			launchLegacy4jClient(s, data);
+			launchLegacy4jClient(s, data, uuid);
 		});
 		((AuthCallback) chooseUserScreen).hotjoin$legacy4jData(data);
 		Minecraft.getInstance().setScreen(chooseUserScreen);
 	}
 
 	@SuppressWarnings("unchecked")
-	private static <T extends Throwable> void launchLegacy4jClient(String magic, Legacy4JData legacy4JData) throws T {
+	private static <T extends Throwable> void launchLegacy4jClient(String magic, Legacy4JData legacy4JData, String _uuid) throws T {
 		String data;
 		if (legacy4JData != null) {
 			Tag tag = Legacy4JData.CODEC.encodeStart(NbtOps.INSTANCE, legacy4JData).resultOrPartial(HotJoin.LOGGER::error).orElseThrow();
@@ -92,7 +93,7 @@ private static <T extends Throwable> void launchLegacy4jClient(String magic, Leg
 		} else {
 			data = null;
 		}
-		UUID uuid = HotJoinAccess.launchMinecraftClient("legacy4j", magic, data);
+		UUID uuid = HotJoinAccess.launchMinecraftClient("legacy4j", magic, data, _uuid);
 		if (legacy4JData != null) uuidLegacy4JMap.put(uuid, legacy4JData);
 	}
 

src/main/java/dev/jab125/hotjoin/mixin/authme/MicrosoftAuthScreenMixin.java

@@ -3,6 +3,7 @@
 import com.google.common.io.ByteArrayDataOutput;
 import com.google.common.io.ByteStreams;
 import dev.jab125.hotjoin.HotJoin;
+import dev.jab125.hotjoin.mixin.UserAccessor;
 import dev.jab125.hotjoin.util.AuthCallback;
 import dev.jab125.hotjoin.util.HotJoinCodecs;
 import me.axieum.mcmod.authme.api.gui.AuthScreen;
@@ -21,14 +22,14 @@
 import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
 
 import java.util.Base64;
-import java.util.function.Consumer;
+import java.util.function.BiConsumer;
 
 @Mixin(MicrosoftAuthScreen.class)
 public abstract class MicrosoftAuthScreenMixin extends AuthScreen implements AuthCallback {
 	public MicrosoftAuthScreenMixin() {
 		super(null, null, null);
 	}
-	private @Unique @Nullable Consumer<String> authResponse;
+	private @Unique @Nullable BiConsumer<String, String> authResponse;
 
 	@Inject(method = "lambda$init$7", at = @At("HEAD"), cancellable = true)
 	void d(User session, CallbackInfo ci) {
@@ -37,7 +38,7 @@ void d(User session, CallbackInfo ci) {
 			Tag tag = HotJoinCodecs.USER_CODEC.encodeStart(NbtOps.INSTANCE, session).resultOrPartial(HotJoin.LOGGER::error).orElseThrow();
 			ByteArrayDataOutput byteArrayDataOutput = ByteStreams.newDataOutput();
 			NbtIo.write((CompoundTag) tag, byteArrayDataOutput);
-			authResponse.accept(Base64.getEncoder().encodeToString(byteArrayDataOutput.toByteArray()));
+			authResponse.accept(((UserAccessor)session).getUUID().toString(), Base64.getEncoder().encodeToString(byteArrayDataOutput.toByteArray()));
 			this.success = true;
 			ci.cancel();
 			return;
@@ -48,12 +49,12 @@ void d(User session, CallbackInfo ci) {
 	}
 
 	@Override
-	public void hotjoin$authResponse(Consumer<String> authConsumer) {
+	public void hotjoin$authResponse(BiConsumer<String, String> authConsumer) {
 		authResponse = authConsumer;
 	}
 
 	@Override
-	public Consumer<String> hotjoin$authResponse() {
+	public BiConsumer<String, String> hotjoin$authResponse() {
 		return authResponse;
 	}
 }

src/main/java/dev/jab125/hotjoin/mixin/legacy4j/ChooseUserScreenMixin.java

@@ -2,40 +2,30 @@
 
 import dev.jab125.hotjoin.compat.legacy4j.Legacy4JData;
 import dev.jab125.hotjoin.util.AuthCallback;
-import net.minecraft.client.gui.GuiGraphics;
-import net.minecraft.client.gui.components.Renderable;
-import net.minecraft.client.gui.screens.Screen;
-import net.minecraft.network.chat.Component;
 import org.jetbrains.annotations.Nullable;
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.Unique;
-import org.spongepowered.asm.mixin.injection.At;
-import org.spongepowered.asm.mixin.injection.Inject;
-import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
 import wily.legacy.client.screen.ChooseUserScreen;
-import wily.legacy.client.screen.Panel;
 import wily.legacy.client.screen.PanelVListScreen;
-import wily.legacy.client.screen.RenderableVListScreen;
 
-import java.util.function.Consumer;
-import java.util.function.Function;
+import java.util.function.BiConsumer;
 
 @Mixin(ChooseUserScreen.class)
 public abstract class ChooseUserScreenMixin extends PanelVListScreen implements AuthCallback {
-	private @Unique @Nullable Consumer<String> authResponse;
+	private @Unique @Nullable BiConsumer<String, String> authResponse;
 
 	@SuppressWarnings("DataFlowIssue")
 	public ChooseUserScreenMixin() {
 		super(null, null);
 	}
 
 	@Override
-	public void hotjoin$authResponse(Consumer<String> authConsumer) {
+	public void hotjoin$authResponse(BiConsumer<String, String> authConsumer) {
 		this.authResponse = authConsumer;
 	}
 
 	@Override
-	public Consumer<String> hotjoin$authResponse() {
+	public BiConsumer<String, String> hotjoin$authResponse() {
 		return this.authResponse;
 	}
 

src/main/java/dev/jab125/hotjoin/mixin/legacy4j/MCAccountMixin.java

@@ -4,6 +4,7 @@
 import com.google.common.io.ByteStreams;
 import dev.jab125.hotjoin.HotJoin;
 import dev.jab125.hotjoin.compat.legacy4j.Legacy4JModCompat;
+import dev.jab125.hotjoin.mixin.UserAccessor;
 import dev.jab125.hotjoin.util.AuthCallback;
 import dev.jab125.hotjoin.util.HotJoinCodecs;
 import net.minecraft.client.Minecraft;
@@ -43,7 +44,7 @@ private static void interceptSetUser(User user, CallbackInfo ci) throws IOExcept
 			Tag tag = HotJoinCodecs.USER_CODEC.encodeStart(NbtOps.INSTANCE, user).resultOrPartial(HotJoin.LOGGER::error).orElseThrow();
 			ByteArrayDataOutput byteArrayDataOutput = ByteStreams.newDataOutput();
 			NbtIo.write((CompoundTag) tag, byteArrayDataOutput);
-			Legacy4JModCompat.authConsumer.accept(Base64.getEncoder().encodeToString(byteArrayDataOutput.toByteArray()));
+			Legacy4JModCompat.authConsumer.accept(((UserAccessor)user).getUUID().toString(), Base64.getEncoder().encodeToString(byteArrayDataOutput.toByteArray()));
 			Legacy4JModCompat.authConsumer = null;
 			ci.cancel();
 		}

src/main/java/dev/jab125/hotjoin/util/AuthCallback.java

@@ -1,11 +1,11 @@
 package dev.jab125.hotjoin.util;
 
-import java.util.function.Consumer;
+import java.util.function.BiConsumer;
 
 public interface AuthCallback {
-	void hotjoin$authResponse(Consumer<String> authConsumer);
+	void hotjoin$authResponse(BiConsumer<String /*uuid*/, String /*magic*/> authConsumer);
 
-	Consumer<String> hotjoin$authResponse();
+	BiConsumer<String, String> hotjoin$authResponse();
 
 	@SuppressWarnings("UnnecessaryReturnStatement")
 	default void hotjoin$legacy4jData(Object object) {