Toolbelt capability passthrough

src/main/java/gregtech/api/capability/GregtechCapabilities.java

@@ -2,6 +2,7 @@
 
 import gregtech.api.GTValues;
 import gregtech.api.capability.impl.EUToFEProvider;
+import gregtech.api.items.toolitem.ItemGTToolbelt;
 import gregtech.api.util.GTUtility;
 import gregtech.common.metatileentities.converter.ConverterTrait;
 
@@ -22,6 +23,9 @@ public class GregtechCapabilities {
     @CapabilityInject(IElectricItem.class)
     public static Capability<IElectricItem> CAPABILITY_ELECTRIC_ITEM = null;
 
+    @CapabilityInject(ItemGTToolbelt.ToolStackHandler.class)
+    public static Capability<ItemGTToolbelt.ToolStackHandler> CAPABILITY_TOOLBELT_HANDLER = null;
+
     @CapabilityInject(IMultiblockController.class)
     public static Capability<IMultiblockController> CAPABILITY_MULTIBLOCK_CONTROLLER = null;
 

src/main/java/gregtech/api/capability/SimpleCapabilityManager.java

@@ -2,6 +2,7 @@
 
 import gregtech.api.capability.impl.AbstractRecipeLogic;
 import gregtech.api.cover.CoverHolder;
+import gregtech.api.items.toolitem.ItemGTToolbelt;
 import gregtech.api.metatileentity.multiblock.IMaintenance;
 import gregtech.api.worldgen.generator.GTWorldGenCapability;
 import gregtech.common.metatileentities.converter.ConverterTrait;
@@ -37,6 +38,7 @@ public void readNBT(Capability<T> capability, T instance, EnumFacing side, NBTBa
     public static void init() {
         registerCapabilityWithNoDefault(IEnergyContainer.class);
         registerCapabilityWithNoDefault(IElectricItem.class);
+        registerCapabilityWithNoDefault(ItemGTToolbelt.ToolStackHandler.class);
         registerCapabilityWithNoDefault(IWorkable.class);
         registerCapabilityWithNoDefault(CoverHolder.class);
         registerCapabilityWithNoDefault(IControllable.class);

src/main/java/gregtech/api/items/toolitem/ItemGTToolbelt.java

@@ -1,6 +1,7 @@
 package gregtech.api.items.toolitem;
 
 import gregtech.api.GregTechAPI;
+import gregtech.api.capability.GregtechCapabilities;
 import gregtech.api.items.IDyeableItem;
 import gregtech.api.items.gui.ItemUIFactory;
 import gregtech.api.items.toolitem.behavior.IToolBehavior;
@@ -141,8 +142,8 @@ public ModularPanel buildUI(HandGuiData guiData, PanelSyncManager guiSyncManager
                                                 (newItem, onlyAmountChanged, client, init) -> handler
                                                         .onContentsChanged(index)))
                                 .background(GTGuiTextures.SLOT, GTGuiTextures.TOOL_SLOT_OVERLAY)
-                                .debugName("slot_" + index))
-                        .debugName("toolbelt_inventory"))
+                                .name("slot_" + index))
+                        .name("toolbelt_inventory"))
                 .bindPlayerInventory();
     }
 
@@ -265,7 +266,7 @@ public boolean shouldCauseReequipAnimation(@NotNull ItemStack oldStack, @NotNull
     }
 
     @Override
-    public int getMetadata(ItemStack stack) {
+    public int getMetadata(@NotNull ItemStack stack) {
         ItemStack selected = getHandler(stack).getSelectedStack();
         if (!selected.isEmpty()) {
             return selected.getItem().getMetadata(selected);
@@ -420,7 +421,7 @@ public boolean supportsTool(ItemStack stack, ItemStack tool) {
     }
 
     private ToolStackHandler getHandler(ItemStack stack) {
-        IItemHandler handler = stack.getCapability(CapabilityItemHandler.ITEM_HANDLER_CAPABILITY, null);
+        IItemHandler handler = stack.getCapability(GregtechCapabilities.CAPABILITY_TOOLBELT_HANDLER, null);
         if (handler instanceof ToolStackHandler h) return h;
         else return FALLBACK;
     }
@@ -441,8 +442,7 @@ public void changeSelectedToolMousewheel(int direction, ItemStack stack) {
     @SideOnly(Side.CLIENT)
     public void changeSelectedToolHotkey(int slot, ItemStack stack) {
         ToolStackHandler handler = getHandler(stack);
-        if (slot < 0 || slot >= handler.getSlots()) handler.selectedSlot = -1;
-        else handler.selectedSlot = slot;
+        handler.setSelectedSlot(slot);
         PacketToolbeltSelectionChange.toServer(handler.selectedSlot);
     }
 
@@ -569,14 +569,25 @@ public ToolbeltCapabilityProvider(ItemStack stack) {
 
         @Override
         public boolean hasCapability(@NotNull Capability<?> capability, EnumFacing facing) {
-            return capability == CapabilityItemHandler.ITEM_HANDLER_CAPABILITY;
+            if (capability == GregtechCapabilities.CAPABILITY_TOOLBELT_HANDLER)
+                return true;
+            ItemStack selected = getHandler().getSelectedStack();
+            if (!selected.isEmpty()) {
+                return selected.hasCapability(capability, facing);
+            } else return capability == CapabilityItemHandler.ITEM_HANDLER_CAPABILITY;
         }
 
         @Override
         public <T> T getCapability(@NotNull Capability<T> capability, EnumFacing facing) {
-            if (capability == CapabilityItemHandler.ITEM_HANDLER_CAPABILITY)
+            if (capability == GregtechCapabilities.CAPABILITY_TOOLBELT_HANDLER)
+                return GregtechCapabilities.CAPABILITY_TOOLBELT_HANDLER.cast(this.getHandler());
+            ItemStack selected = getHandler().getSelectedStack();
+            if (!selected.isEmpty()) {
+                return selected.getCapability(capability, facing);
+            } else if (capability == CapabilityItemHandler.ITEM_HANDLER_CAPABILITY) {
+                // if nothing is selected, expose the handler under the item handler capability
                 return CapabilityItemHandler.ITEM_HANDLER_CAPABILITY.cast(this.getHandler());
-            else return null;
+            } else return null;
         }
 
         @Override
@@ -616,7 +627,7 @@ public void readNBTShareTag(ItemStack stack, NBTTagCompound nbt) {
 
     protected static final ToolStackHandler FALLBACK = new ToolStackHandler(0);
 
-    protected static class ToolStackHandler extends ItemStackHandler {
+    public static class ToolStackHandler extends ItemStackHandler {
 
         private static final Set<String> EMPTY = ImmutableSet.of();
 
@@ -646,7 +657,8 @@ public int getSelectedSlot() {
         }
 
         public void setSelectedSlot(int selectedSlot) {
-            this.selectedSlot = Math.min(getSlots() - 1, Math.max(selectedSlot, -1));
+            if (selectedSlot >= getSlots() || selectedSlot < 0) this.selectedSlot = -1;
+            else this.selectedSlot = selectedSlot;
         }
 
         public void enablePassthrough() {