Auto create config gui if no gui factory is registered

src/main/java/com/gtnewhorizon/gtnhlib/config/Config.java

@@ -216,4 +216,12 @@
 
         ModDetectedDefault[] values() default {};
     }
+
+    /**
+     * Excludes this class from the auto config GUI, only applicable to a {@link Config} annotated class. Has no effect
+     * if a gui factory is registered for the mod.
+     */
+    @Retention(RetentionPolicy.RUNTIME)
+    @Target(ElementType.TYPE)
+    @interface ExcludeFromAutoGui {}
 }

src/main/java/com/gtnewhorizon/gtnhlib/config/ConfigurationManager.java

@@ -43,6 +43,7 @@ public class ConfigurationManager {
     static final Logger LOGGER = LogManager.getLogger("GTNHLibConfig");
     private static final Map<String, Configuration> configs = new HashMap<>();
     private static final Map<Configuration, Map<String, Set<Class<?>>>> configToCategoryClassMap = new HashMap<>();
+    private static final Map<String, Set<Class<?>>> modIdToConfigClasses = new HashMap<>();
     private static final String[] langKeyPlaceholders = new String[] { "%mod", "%file", "%cat", "%field" };
     private static final Boolean PRINT_KEYS = Boolean.getBoolean("gtnhlib.printkeys");
     private static final Boolean DUMP_KEYS = Boolean.getBoolean("gtnhlib.dumpkeys");
@@ -68,6 +69,10 @@ public static void registerConfig(Class<?> configClass) throws ConfigException {
         val modid = cfg.modid();
         val filename = Optional.of(cfg.filename().trim()).filter(s -> !s.isEmpty()).orElse(modid);
 
+        if (!configClass.isAnnotationPresent(Config.ExcludeFromAutoGui.class)) {
+            modIdToConfigClasses.computeIfAbsent(modid, (ignored) -> new HashSet<>()).add(configClass);
+        }
+
         Configuration rawConfig = configs.computeIfAbsent(getConfigKey(cfg), (ignored) -> {
             Path newConfigDir = configDir;
             if (!cfg.configSubDirectory().trim().isEmpty()) {
@@ -447,6 +452,14 @@ private static File minecraftHome() {
         return Launch.minecraftHome != null ? Launch.minecraftHome : new File(".");
     }
 
+    public static boolean isModRegistered(String modid) {
+        return modIdToConfigClasses.containsKey(modid);
+    }
+
+    static Class<?>[] getConfigClasses(String modid) {
+        return modIdToConfigClasses.getOrDefault(modid, Collections.emptySet()).toArray(new Class<?>[0]);
+    }
+
     public static void onInit() {
         cullDeadCategories();
         if (DUMP_KEYS) {

src/main/java/com/gtnewhorizon/gtnhlib/config/SimpleGuiConfig.java

@@ -11,20 +11,18 @@ public class SimpleGuiConfig extends GuiConfig {
 
     public SimpleGuiConfig(GuiScreen parent, Class<?> configClass, String modID, String modName)
             throws ConfigException {
-        super(
-                parent,
-                ConfigurationManager.getConfigElements(configClass),
-                modID,
-                false,
-                false,
-                modName + " Configuration");
+        this(parent, modID, modName, false, configClass);
     }
 
     public SimpleGuiConfig(GuiScreen parent, String modID, String modName, Class<?>... configClasses)
             throws ConfigException {
         this(parent, modID, modName, false, configClasses);
     }
 
+    public SimpleGuiConfig(GuiScreen parent, String modID, String modName) throws ConfigException {
+        this(parent, modID, modName, true, ConfigurationManager.getConfigClasses(modID));
+    }
+
     public SimpleGuiConfig(GuiScreen parent, String modID, String modName, boolean categorized,
             Class<?>... configClasses) throws ConfigException {
         super(

src/main/java/com/gtnewhorizon/gtnhlib/mixins/Mixins.java

@@ -18,8 +18,12 @@ public enum Mixins {
             .setApplyIf(() -> true).addMixinClasses("MixinTessellator")),
     WAVEFRONT_VBO(new Builder("WavefrontObject").addTargetedMod(TargetedMod.VANILLA).setSide(Side.CLIENT)
             .setPhase(Phase.EARLY).setApplyIf(() -> true).addMixinClasses("MixinWavefrontObject")),
+
+    GUI_MOD_LIST(new Builder("Auto config ui").addTargetedMod(TargetedMod.VANILLA).setSide(Side.CLIENT)
+            .setPhase(Phase.EARLY).addMixinClasses("fml.MixinGuiModList")),
+
     EVENT_BUS_ACCESSOR(new Builder("EventBusAccessor").addTargetedMod(TargetedMod.VANILLA).setSide(Side.BOTH)
-            .setPhase(Phase.EARLY).addMixinClasses("fml.EventBusAccessor", "fml.EnumHolderAccessor")),;
+            .setPhase(Phase.EARLY).addMixinClasses("fml.EventBusAccessor", "fml.EnumHolderAccessor"));
 
     private final List<String> mixinClasses;
     private final Supplier<Boolean> applyIf;

src/main/java/com/gtnewhorizon/gtnhlib/mixins/early/fml/MixinGuiModList.java

@@ -0,0 +1,63 @@
+package com.gtnewhorizon.gtnhlib.mixins.early.fml;
+
+import net.minecraft.client.gui.GuiButton;
+import net.minecraft.client.gui.GuiScreen;
+
+import org.spongepowered.asm.lib.Opcodes;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+import com.gtnewhorizon.gtnhlib.config.ConfigException;
+import com.gtnewhorizon.gtnhlib.config.ConfigurationManager;
+import com.gtnewhorizon.gtnhlib.config.SimpleGuiConfig;
+import com.llamalad7.mixinextras.sugar.Local;
+
+import cpw.mods.fml.client.GuiModList;
+import cpw.mods.fml.client.IModGuiFactory;
+import cpw.mods.fml.common.ModContainer;
+
+@Mixin(GuiModList.class)
+public abstract class MixinGuiModList extends GuiScreen {
+
+    @Shadow(remap = false)
+    private ModContainer selectedMod;
+
+    @Shadow(remap = false)
+    private GuiButton configModButton;
+
+    @Inject(
+            method = "actionPerformed",
+            at = @At(
+                    value = "INVOKE",
+                    target = "Lcpw/mods/fml/client/IModGuiFactory;mainConfigGuiClass()Ljava/lang/Class;",
+                    remap = false),
+            cancellable = true)
+    private void gtnhlib$autoCreateGuiConfig(GuiButton button, CallbackInfo ci, @Local IModGuiFactory guiFactory) {
+        if (guiFactory == null && ConfigurationManager.isModRegistered(selectedMod.getModId())) {
+            ci.cancel();
+            try {
+                GuiScreen config = new SimpleGuiConfig(this, selectedMod.getModId(), selectedMod.getName());
+                mc.displayGuiScreen(config);
+            } catch (ConfigException e) {
+                throw new RuntimeException(e);
+            }
+        }
+    }
+
+    @Inject(
+            method = "drawScreen",
+            at = @At(
+                    value = "FIELD",
+                    opcode = Opcodes.PUTFIELD,
+                    target = "Lnet/minecraft/client/gui/GuiButton;enabled:Z",
+                    shift = At.Shift.AFTER,
+                    ordinal = 4))
+    private void gtnhlib$checkForRegisteredConfig(int p_571_1_, int p_571_2_, float p_571_3_, CallbackInfo ci) {
+        if (ConfigurationManager.isModRegistered(selectedMod.getModId())) {
+            configModButton.enabled = true;
+        }
+    }
+}