fix clicking for phantom fluid slots

simplify getting fluid from buckets
simplify drain method

Author: ghzdude

src/main/java/gregtech/common/metatileentities/storage/MetaTileEntityCreativeTank.java

@@ -240,12 +240,8 @@ public FluidStack drain(FluidStack resource, boolean doDrain) {
         public FluidStack drain(int maxDrain, boolean doDrain) {
             if (!active) return null;
 
-            var f = super.drain(maxDrain, false);
-            if (f != null) {
-                f = f.copy();
-                f.amount = Math.min(mBPerCycle, maxDrain);
-            }
-            return f;
+            FluidStack stack = super.drain(maxDrain, false);
+            return GTUtility.copy(Math.min(mBPerCycle, maxDrain), stack);
         }
 
         @Override

src/main/java/gregtech/common/mui/widget/GTFluidSlot.java

@@ -1,13 +1,12 @@
 package gregtech.common.mui.widget;
 
 import gregtech.api.mui.sync.GTFluidSyncHandler;
-import gregtech.api.util.GTUtility;
 import gregtech.client.utils.RenderUtil;
 
 import net.minecraft.item.ItemStack;
 import net.minecraftforge.fluids.FluidStack;
+import net.minecraftforge.fluids.FluidUtil;
 import net.minecraftforge.fluids.IFluidTank;
-import net.minecraftforge.fluids.capability.CapabilityFluidHandler;
 
 import com.cleanroommc.modularui.api.ITheme;
 import com.cleanroommc.modularui.api.widget.Interactable;
@@ -119,7 +118,8 @@ public void draw(ModularGuiContext context, WidgetSlotTheme widgetTheme) {
     @Override
     public @NotNull Result onMousePressed(int mouseButton) {
         var data = MouseData.create(mouseButton);
-        if (this.syncHandler.canFillSlot() || this.syncHandler.canDrainSlot()) {
+        if (this.syncHandler.isPhantom() ||
+                this.syncHandler.canFillSlot() || this.syncHandler.canDrainSlot()) {
             this.syncHandler.handleClick(data);
 
             if (this.syncHandler.canLockFluid())
@@ -164,13 +164,12 @@ public void setGhostIngredient(@NotNull FluidStack ingredient) {
 
         if (ingredient instanceof FluidStack stack) {
             return stack;
-        } else if (ingredient instanceof ItemStack stack &&
-                stack.hasCapability(CapabilityFluidHandler.FLUID_HANDLER_ITEM_CAPABILITY, null)) {
-                    if (stack.getCount() > 1) stack = GTUtility.copy(1, stack);
+        }
+
+        if (ingredient instanceof ItemStack stack) {
+            return FluidUtil.getFluidContained(stack);
+        }
 
-                    var handler = stack.getCapability(CapabilityFluidHandler.FLUID_HANDLER_ITEM_CAPABILITY, null);
-                    return handler == null ? null : handler.drain(Integer.MAX_VALUE, true);
-                }
         return null;
     }