Fixed dupe bug.

Closes #29.
Closes #30.

gradle.properties

@@ -1,6 +1,6 @@
 org.gradle.jvmargs=-Xmx6G
 org.gradle.daemon=false
-mod_version=1.2.0
+mod_version=1.2.1
 minecraft_version=1.21
 neo_version=21.0.146
 neogradle.subsystems.parchment.minecraftVersion=1.21

src/main/java/com/flanks255/psu/gui/PSUContainer.java

@@ -119,12 +119,17 @@ public boolean stillValid(Player playerIn) {
         return true;
     }
 
+    @Nonnull
     @Override
     public ItemStack quickMoveStack(Player playerIn, int index) {
         Slot slot = this.slots.get(index);
 
         if (slot != null && slot.hasItem()) {
-            return handler.insertItemSlotless(slot.getItem(), true, true);
+            ItemStack remainder = handler.insertItemSlotless(slot.getItem(), true, true);
+            if (!remainder.isEmpty())
+                slot.set(remainder);
+            else
+                slot.set(ItemStack.EMPTY);
         }
         return ItemStack.EMPTY;
     }

src/main/java/com/flanks255/psu/inventory/PSUItemHandler.java

@@ -85,6 +85,8 @@ public List<PSUSlot> getMatchingSlots(@Nonnull ItemStack stack) {
         return slots.stream().filter(s -> ItemStack.isSameItemSameComponents(s.getStack(), stack)).toList();
     }
 
+    // Inserts an item into the first slot that matches the item.
+    // Returns the remainder of the stack if it could not be fully inserted.
     public ItemStack insertItemSlotless(@Nonnull ItemStack stack, boolean allowEmpty, boolean allowVoid) {
         if (stack.isEmpty() || !isItemValid(0, stack))
             return ItemStack.EMPTY;
@@ -113,9 +115,7 @@ public ItemStack insertItemSlotless(@Nonnull ItemStack stack, boolean allowEmpty
                 if (slots.get(n).isEmpty()) {
                     slots.set(n, new PSUSlot(stack));
                     onContentsChanged();
-                    ItemStack tmpstack = stack.copy();
-                    stack.setCount(0);
-                    return tmpstack;
+                    return ItemStack.EMPTY;
                 }
             }
         }