🐛 Resolve incompatibility with FAPI item group API where custom creative tabs would be randomly ordered when tabbed through

build.gradle.kts

@@ -74,6 +74,7 @@ dependencies {
         "fabric-screen-api-v1",
         "fabric-command-api-v2",
         "fabric-networking-api-v1",
+        "fabric-item-group-api-v1",
     ).forEach {
         modImplementation(fabricApi.module(it, libs.versions.fabric.api.get()))
     }

src/main/java/dev/isxander/controlify/screenop/compat/vanilla/CreativeModeInventoryScreenProcessor.java

@@ -3,12 +3,19 @@ package dev.isxander.controlify.screenop.compat.vanilla;
 import dev.isxander.controlify.controller.Controller;
 import dev.isxander.controlify.mixins.feature.screenop.vanilla.CreativeModeInventoryScreenAccessor;
 import dev.isxander.controlify.virtualmouse.VirtualMouseHandler;
+import net.fabricmc.fabric.impl.client.itemgroup.CreativeGuiExtensions;
+import net.fabricmc.fabric.impl.client.itemgroup.FabricCreativeGuiComponents;
+import net.fabricmc.fabric.impl.itemgroup.FabricItemGroup;
 import net.minecraft.client.gui.screens.inventory.CreativeModeInventoryScreen;
 import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.CreativeModeTab;
 import net.minecraft.world.item.CreativeModeTabs;
 
+import java.util.Comparator;
+import java.util.List;
 import java.util.function.Supplier;
 
+@SuppressWarnings("UnstableApiUsage") // TODO: requires FAPI impl stuff to get pages working. will be changed in future FAPI update (hopefully)
 public class CreativeModeInventoryScreenProcessor extends AbstractContainerScreenProcessor<CreativeModeInventoryScreen> {
     public CreativeModeInventoryScreenProcessor(CreativeModeInventoryScreen screen, Supplier<Slot> hoveredSlot, ClickSlotFunction clickSlotFunction) {
         super(screen, hoveredSlot, clickSlotFunction);
@@ -17,20 +24,78 @@ public class CreativeModeInventoryScreenProcessor extends AbstractContainerScree
     @Override
     protected void handleScreenVMouse(Controller<?, ?> controller, VirtualMouseHandler vmouse) {
         var accessor = (CreativeModeInventoryScreenAccessor) screen;
+        var ext = (CreativeGuiExtensions) screen;
 
+        var tabs = getTabsOnCurrentPage(ext);
         if (controller.bindings().GUI_NEXT_TAB.justPressed()) {
-            var tabs = CreativeModeTabs.tabs();
             int newIndex = tabs.indexOf(CreativeModeInventoryScreenAccessor.getSelectedTab()) + 1;
-            if (newIndex >= tabs.size()) newIndex = 0;
+            if (newIndex >= tabs.size()) {
-            accessor.invokeSelectTab(tabs.get(newIndex));
+                newIndex = 0;
+
+                int currentPage = ext.fabric_currentPage();
+                ext.fabric_nextPage();
+                if (ext.fabric_currentPage() == currentPage) {
+                    for (int i = 0; i < currentPage; i++) {
+                        ext.fabric_previousPage();
+                    }
+                }
+            }
+            accessor.invokeSelectTab(getTabsOnCurrentPage(ext).get(newIndex));
         }
         if (controller.bindings().GUI_PREV_TAB.justPressed()) {
-            var tabs = CreativeModeTabs.tabs();
             int newIndex = tabs.indexOf(CreativeModeInventoryScreenAccessor.getSelectedTab()) - 1;
-            if (newIndex < 0) newIndex = tabs.size() - 1;
+            if (newIndex < 0) {
-            accessor.invokeSelectTab(tabs.get(newIndex));
+                if (ext.fabric_currentPage() == 0) {
+                    for (int i = 0; i < getLastPage(ext); i++) {
+                        ext.fabric_nextPage();
                     }
+                } else {
+                    ext.fabric_previousPage();
+                }
+
+                newIndex = getTabsOnCurrentPage(ext).size() - 1;
+            }
+            accessor.invokeSelectTab(getTabsOnCurrentPage(ext).get(newIndex));
+        }
+
 
         super.handleScreenVMouse(controller, vmouse);
     }
+
+    private static List<CreativeModeTab> getTabsOnCurrentPage(CreativeGuiExtensions ext) {
+        return CreativeModeTabs.tabs().stream() // just gets visible tabs from registry (excludes operator tab if disabled)
+                .filter(tab -> ext.fabric_currentPage() == getFabricPage(ext, tab)) // only want current page of tabs, not all of them
+                .sorted(Comparator.comparing(CreativeModeTab::row).thenComparingInt(CreativeModeTab::column)) // in hash order from the registry.
+                .sorted((a, b) -> {
+                    // make stuff aligned to the right go last
+                    if (a.isAlignedRight() && !b.isAlignedRight()) return 1;
+                    if (!a.isAlignedRight() && b.isAlignedRight()) return -1;
+                    return 0;
+                })
+                .toList();
+    }
+
+    // straight up ripped from fapi impl
+    private static int getFabricPage(CreativeGuiExtensions ext, CreativeModeTab tab) {
+        if (FabricCreativeGuiComponents.COMMON_GROUPS.contains(tab)) {
+            return ext.fabric_currentPage();
+        }
+
+        final FabricItemGroup fabricItemGroup = (FabricItemGroup) tab;
+        return fabricItemGroup.getPage();
+    }
+
+    // this is the only way to get the last page of tabs, since fapi doesn't expose it
+    private static int getLastPage(CreativeGuiExtensions ext) {
+        int lastPage = 0;
+        while (hasGroupForPage(ext, lastPage)) {
+            lastPage++;
+        }
+        return lastPage - 1;
+    }
+
+    private static boolean hasGroupForPage(CreativeGuiExtensions ext, int page) {
+        return CreativeModeTabs.tabs().stream()
+                .anyMatch(itemGroup -> getFabricPage(ext, itemGroup) == page);
+    }
 }