Data pack configuration while loaded in world

src/main/java/ml/unbreakinggold/datapackinstaller/mixin/GameMenuScreenMixin.java

@@ -0,0 +1,40 @@
+package ml.unbreakinggold.datapackinstaller.mixin;
+
+import ml.unbreakinggold.datapackinstaller.client.DatapackInstallerClient;
+import net.minecraft.client.gui.screen.GameMenuScreen;
+import net.minecraft.client.gui.screen.Screen;
+import net.minecraft.client.gui.screen.pack.PackScreen;
+import net.minecraft.client.gui.widget.ButtonWidget;
+import net.minecraft.client.gui.widget.GridWidget;
+import net.minecraft.resource.ResourcePackManager;
+import net.minecraft.text.Text;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+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 org.spongepowered.asm.mixin.injection.callback.LocalCapture;
+
+import java.util.function.Supplier;
+
+@Mixin(GameMenuScreen.class)
+public abstract class GameMenuScreenMixin extends Screen {
+    @Shadow private ButtonWidget createButton(Text text, Supplier<Screen> screenSupplier) { return null; };
+    @Unique private static final Text DATA_PACK_TEXT = Text.translatable("dataPack.title");
+
+    private GameMenuScreenMixin(Text title) {
+        super(title);
+    }
+
+    @Inject(at = @At(value = "INVOKE", target = "Lnet/minecraft/client/MinecraftClient;isInSingleplayer()Z"), method = "initWidgets", locals = LocalCapture.CAPTURE_FAILHARD)
+    private void onInitWidgets(CallbackInfo ci, GridWidget gridWidget, GridWidget.Adder adder) {
+        if (!this.client.isIntegratedServerRunning() || this.client.getServer().isRemote()) return;
+
+        adder.add(this.createButton(DATA_PACK_TEXT, () -> {
+            ResourcePackManager dataPackManager = this.client.getServer().getDataPackManager();
+
+            return new PackScreen(dataPackManager, (manager) -> {}, DatapackInstallerClient.MAIN_PATH, DATA_PACK_TEXT);
+        }));
+    }
+}

src/main/resources/DatapackInstaller.mixins.json

@@ -7,7 +7,7 @@
   ],
   "client": [
     "CreateWorldScreenMixin",
-    "EditWorldScreenMixin"
+    "GameMenuScreenMixin"
   ],
   "injectors": {
     "defaultRequire": 1