Use Property for InventorySlotElement background

This makes InventorySlotElement backgrounds reactive, for usage in `invui-kotlin` via providers

Author: NichtStudioCode

invui-kotlin/src/main/kotlin/xyz/xenondevs/invui/PropertyAdapter.kt

@@ -9,6 +9,7 @@ import xyz.xenondevs.invui.state.MutableProperty
 import xyz.xenondevs.invui.state.Property
 import java.util.function.Consumer
 
+@ExperimentalReactiveApi
 internal class PropertyAdapter<T>(
     val provider: Provider<T>,
     val mutableView: MutableProvider<T>
@@ -55,6 +56,7 @@ internal class NonMutableMutableProvider<T>(override val identifier: Provider<T>
     override fun hashCode(): Int = System.identityHashCode(identifier)
 }
 
+@ExperimentalReactiveApi
 internal fun <T> MutableProperty<T>.toProvider(): MutableProvider<T> {
     if (this is PropertyAdapter<T>) 
         return mutableView
@@ -65,6 +67,7 @@ internal fun <T> MutableProperty<T>.toProvider(): MutableProvider<T> {
     return child
 }
 
+@ExperimentalReactiveApi
 internal fun <T> Property<T>.toProvider(): Provider<T> {
     if (this is PropertyAdapter<T>)
         return provider

invui-kotlin/src/main/kotlin/xyz/xenondevs/invui/dsl/IngredientsDsl.kt

@@ -1,7 +1,11 @@
 @file:Suppress("INAPPLICABLE_JVM_NAME")
+@file:OptIn(ExperimentalReactiveApi::class)
+
 package xyz.xenondevs.invui.dsl
 
 import org.bukkit.inventory.ItemStack
+import xyz.xenondevs.commons.provider.Provider
+import xyz.xenondevs.invui.ExperimentalReactiveApi
 import xyz.xenondevs.invui.gui.Gui
 import xyz.xenondevs.invui.gui.IngredientPreset
 import xyz.xenondevs.invui.gui.Marker
@@ -10,6 +14,7 @@ import xyz.xenondevs.invui.gui.ScrollGui
 import xyz.xenondevs.invui.gui.Slot
 import xyz.xenondevs.invui.gui.SlotElement
 import xyz.xenondevs.invui.gui.TabGui
+import xyz.xenondevs.invui.gui.addIngredient
 import xyz.xenondevs.invui.inventory.Inventory
 import xyz.xenondevs.invui.item.Item
 import xyz.xenondevs.invui.item.ItemProvider
@@ -33,6 +38,8 @@ sealed interface IngredientsDsl {
 
     infix fun Char.by(itemProvider: ItemProvider)
 
+    infix fun Char.by(itemProvider: Provider<ItemProvider>)
+    
     infix fun Char.by(itemStack: ItemStack)
 
     infix fun Char.by(element: SlotElement)
@@ -112,6 +119,10 @@ internal open class IngredientsDslImpl(
         ingredients.addIngredient(this, itemProvider)
     }
 
+    override fun Char.by(itemProvider: Provider<ItemProvider>) {
+        ingredients.addIngredient(this, itemProvider)
+    }
+    
     override fun Char.by(itemStack: ItemStack) {
         ingredients.addIngredient(this, itemStack)
     }

invui-kotlin/src/main/kotlin/xyz/xenondevs/invui/gui/IngredientMapperExtensions.kt

@@ -0,0 +1,17 @@
+package xyz.xenondevs.invui.gui
+
+import xyz.xenondevs.commons.provider.Provider
+import xyz.xenondevs.invui.ExperimentalReactiveApi
+import xyz.xenondevs.invui.PropertyAdapter
+import xyz.xenondevs.invui.inventory.Inventory
+import xyz.xenondevs.invui.item.Item
+import xyz.xenondevs.invui.item.ItemProvider
+import xyz.xenondevs.invui.item.setItemProvider
+
+@ExperimentalReactiveApi
+fun <S : IngredientMapper<S>> IngredientMapper<S>.addIngredient(key: Char, provider: Provider<ItemProvider>): S =
+    addIngredient(key, Item.builder().setItemProvider(provider).build())
+
+@ExperimentalReactiveApi
+fun <S : IngredientMapper<S>> IngredientMapper<S>.addIngredient(key: Char, inventory: Inventory, background: Provider<ItemProvider>, offset: Int = 0): S =
+    addIngredient(key, inventory, PropertyAdapter(background), offset)

invui-kotlin/src/main/kotlin/xyz/xenondevs/invui/gui/SlotElementExtensions.kt

@@ -0,0 +1,11 @@
+package xyz.xenondevs.invui.gui
+
+import xyz.xenondevs.commons.provider.Provider
+import xyz.xenondevs.invui.ExperimentalReactiveApi
+import xyz.xenondevs.invui.PropertyAdapter
+import xyz.xenondevs.invui.inventory.Inventory
+import xyz.xenondevs.invui.item.ItemProvider
+
+@ExperimentalReactiveApi
+fun InventoryLink(inventory: Inventory, slot: Int, background: Provider<ItemProvider>): SlotElement.InventoryLink =
+    SlotElement.InventoryLink(inventory, slot, PropertyAdapter(background))

invui-kotlin/src/test/kotlin/xyz/xenondevs/invui/PropertyAdapterTest.kt

@@ -1,3 +1,5 @@
+@file:OptIn(ExperimentalReactiveApi::class)
+
 package xyz.xenondevs.invui
 
 import org.junit.jupiter.api.Test

invui/src/main/java/xyz/xenondevs/invui/gui/Gui.java

@@ -12,6 +12,7 @@
 import xyz.xenondevs.invui.item.ItemProvider;
 import xyz.xenondevs.invui.item.ItemWrapper;
 import xyz.xenondevs.invui.state.MutableProperty;
+import xyz.xenondevs.invui.state.Property;
 import xyz.xenondevs.invui.window.Window;
 
 import java.util.Collection;
@@ -400,7 +401,7 @@ static Gui single(Inventory inventory, int slot, ItemProvider background) {
      * @see #applyStructure(Structure)
      */
     default void setInventory(char key, Inventory inventory) {
-        setSlotElement(key, new InventorySlotElementSupplier(inventory, null, 0));
+        setSlotElement(key, new InventorySlotElementSupplier(inventory, Property.of(null), 0));
     }
 
     /**
@@ -412,7 +413,7 @@ default void setInventory(char key, Inventory inventory) {
      * @param offset    The slot offset inside the {@link Inventory} to start from
      */
     default void setInventory(char key, Inventory inventory, int offset) {
-        setSlotElement(key, new InventorySlotElementSupplier(inventory, null, offset));
+        setSlotElement(key, new InventorySlotElementSupplier(inventory, Property.of(null), offset));
     }
 
     /**
@@ -425,7 +426,7 @@ default void setInventory(char key, Inventory inventory, int offset) {
      * @see #applyStructure(Structure)
      */
     default void setInventory(char key, Inventory inventory, @Nullable ItemProvider background) {
-        setSlotElement(key, new InventorySlotElementSupplier(inventory, background, 0));
+        setSlotElement(key, new InventorySlotElementSupplier(inventory, Property.of(background), 0));
     }
 
     /**
@@ -438,7 +439,7 @@ default void setInventory(char key, Inventory inventory, @Nullable ItemProvider
      * @param offset     The slot offset inside the {@link Inventory} to start from
      */
     default void setInventory(char key, Inventory inventory, @Nullable ItemProvider background, int offset) {
-        setSlotElement(key, new InventorySlotElementSupplier(inventory, background, offset));
+        setSlotElement(key, new InventorySlotElementSupplier(inventory, Property.of(background), offset));
     }
 
     /**

invui/src/main/java/xyz/xenondevs/invui/gui/IngredientMapper.java

@@ -6,6 +6,7 @@
 import xyz.xenondevs.invui.item.Item;
 import xyz.xenondevs.invui.item.ItemProvider;
 import xyz.xenondevs.invui.item.ItemWrapper;
+import xyz.xenondevs.invui.state.Property;
 
 import java.util.function.Supplier;
 
@@ -99,7 +100,7 @@ default S addIngredient(char key, Inventory inventory) {
      * @return This {@link IngredientMapper}
      */
     default S addIngredient(char key, Inventory inventory, int offset) {
-        return addIngredient(key, inventory, null, offset);
+        return addIngredient(key, inventory, (ItemProvider) null, offset);
     }
 
     /**
@@ -124,6 +125,31 @@ default S addIngredient(char key, Inventory inventory, @Nullable ItemProvider ba
      * @return This {@link IngredientMapper}
      */
     default S addIngredient(char key, Inventory inventory, @Nullable ItemProvider background, int offset) {
+        return addIngredient(key, inventory, Property.of(background), offset);
+    }
+    
+    /**
+     * Adds a {@link Inventory} ingredient under the given key.
+     *
+     * @param key        The key of the ingredient
+     * @param inventory  The {@link Inventory} ingredient
+     * @param background The background {@link ItemProvider} {@link Property} for the {@link Inventory}
+     * @return This {@link IngredientMapper}
+     */
+    default S addIngredient(char key, Inventory inventory, Property<@Nullable ItemProvider> background) {
+        return addIngredient(key, inventory, background, 0);
+    }
+    
+    /**
+     * Adds a {@link Inventory} ingredient with the given offset and background under the given key.
+     *
+     * @param key        The key of the ingredient
+     * @param inventory  The {@link Inventory} ingredient
+     * @param background The background {@link ItemProvider} {@link Property} for the {@link Inventory}
+     * @param offset     The slot offset inside the {@link Inventory} to start from
+     * @return This {@link IngredientMapper}
+     */
+    default S addIngredient(char key, Inventory inventory, Property<@Nullable ItemProvider> background, int offset) {
         return addIngredient(key, new InventorySlotElementSupplier(inventory, background, offset));
     }
 

invui/src/main/java/xyz/xenondevs/invui/gui/InventorySlotElementSupplier.java

@@ -3,17 +3,18 @@
 import org.jspecify.annotations.Nullable;
 import xyz.xenondevs.invui.inventory.Inventory;
 import xyz.xenondevs.invui.item.ItemProvider;
+import xyz.xenondevs.invui.state.Property;
 
 import java.util.ArrayList;
 import java.util.List;
 
 class InventorySlotElementSupplier implements SlotElementSupplier {
 
     private final Inventory inventory;
-    private final @Nullable ItemProvider background;
+    private final Property<@Nullable ItemProvider> background;
     private final int offset;
 
-    public InventorySlotElementSupplier(Inventory inventory, @Nullable ItemProvider background, int offset) {
+    public InventorySlotElementSupplier(Inventory inventory, Property<@Nullable ItemProvider> background, int offset) {
         if (inventory.getSize() <= 0)
             throw new IllegalArgumentException("Illegal inventory size: " + inventory.getSize());
         if (offset >= inventory.getSize())

invui/src/main/java/xyz/xenondevs/invui/gui/SlotElement.java

@@ -10,6 +10,7 @@
 import xyz.xenondevs.invui.i18n.Languages;
 import xyz.xenondevs.invui.inventory.Inventory;
 import xyz.xenondevs.invui.item.ItemProvider;
+import xyz.xenondevs.invui.state.Property;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -105,9 +106,11 @@ public int getUpdatePeriod() {
      *
      * @param inventory  The {@link Inventory} to link to
      * @param slot       The slot in the {@link Inventory} to link to
-     * @param background The {@link ItemProvider} to use as background if the slot is empty
+     * @param backgroundProperty The property containing the {@link ItemProvider} to use as background if the linked slot is empty.
      */
-    record InventoryLink(Inventory inventory, int slot, @Nullable ItemProvider background) implements SlotElement {
+    record InventoryLink(Inventory inventory, int slot,
+                         Property<@Nullable ItemProvider> backgroundProperty) implements SlotElement
+    {
 
         /**
          * Creates a new {@link InventoryLink} using the given {@link Inventory} and slot.
@@ -116,12 +119,33 @@ record InventoryLink(Inventory inventory, int slot, @Nullable ItemProvider backg
          * @param slot      The slot in the {@link Inventory} to link to
          */
         public InventoryLink(Inventory inventory, int slot) {
-            this(inventory, slot, null);
+            this(inventory, slot, (ItemProvider) null);
+        }
+        
+        /**
+         * Creates a new {@link InventoryLink} using the given {@link Inventory}, slot and background {@link ItemProvider}.
+         *
+         * @param inventory  The {@link Inventory} to link to
+         * @param slot       The slot in the {@link Inventory} to link to
+         * @param background The {@link ItemProvider} to use as background if the linked slot is empty.
+         */
+        public InventoryLink(Inventory inventory, int slot, @Nullable ItemProvider background) {
+            this(inventory, slot, Property.of(background));
+        }
+        
+        /**
+         * Gets the background {@link ItemProvider}.
+         *
+         * @return The background {@link ItemProvider}
+         */
+        public @Nullable ItemProvider background() {
+            return backgroundProperty().get();
         }
 
         @Override
         public @Nullable ItemStack getItemStack(Player player) {
             ItemStack itemStack = inventory.getUnsafeItem(slot);
+            ItemProvider background = backgroundProperty().get();
             if (itemStack == null && background != null)
                 itemStack = background.get(Languages.getInstance().getLocale(player));
             return itemStack;
@@ -135,11 +159,13 @@ public SlotElement getHoldingElement() {
         @Override
         public void addObserver(Observer who, int how) {
             inventory.addObserver(who, slot, how);
+            backgroundProperty.observeWeak(this, thisRef -> thisRef.inventory.notifyWindows(slot));
         }
 
         @Override
         public void removeObserver(Observer who, int how) {
             inventory.removeObserver(who, slot, how);
+            backgroundProperty.unobserveWeak(this);
         }
 
         @Override

invui/src/test/java/xyz/xenondevs/invui/Utils.java

@@ -13,7 +13,7 @@ public class Utils {
     public static void assertSlotElements(Gui gui, @Nullable SlotElement... elements) {
         assertEquals(gui.getSize(), elements.length);
         for (int i = 0; i < elements.length; i++) {
-            assertEquals(elements[i], gui.getSlotElement(i), "i=" + i);
+            assertSlotElementEquals(elements[i], gui.getSlotElement(i), "i=" + i);
         }
     }
 
@@ -30,6 +30,16 @@ public static void assertItems(Gui gui, @Nullable Item... items) {
         }
     }
 
+    public static void assertSlotElementEquals(SlotElement expected, SlotElement actual, String message) {
+        if (expected instanceof SlotElement.InventoryLink el && actual instanceof SlotElement.InventoryLink al) {
+            assertEquals(el.inventory(), al.inventory(), message);
+            assertEquals(el.slot(), al.slot(), message);
+            assertEquals(el.background(), al.background(), message);
+        } else {
+            assertEquals(expected, actual, message);
+        }
+    }
+    
     public static SlotElement.InventoryLink il(Inventory inventory, int slot) {
         return new SlotElement.InventoryLink(inventory, slot);
     }