From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jake Potrebic <jake.m.potrebic@gmail.com>
Date: Sat, 8 May 2021 15:01:54 -0700
Subject: [PATCH] Improve item default attribute API

Also fixes an issue where upstream isn't
actually getting the correct default attributes

diff --git a/src/main/java/org/bukkit/craftbukkit/attribute/CraftAttributeInstance.java b/src/main/java/org/bukkit/craftbukkit/attribute/CraftAttributeInstance.java
index 8afbb8e0cb368e95f23bb78c1261f9aa9b8abd86..0a18983151d17b8e1460b82326b0380087e13795 100644
--- a/src/main/java/org/bukkit/craftbukkit/attribute/CraftAttributeInstance.java
+++ b/src/main/java/org/bukkit/craftbukkit/attribute/CraftAttributeInstance.java
@@ -74,7 +74,7 @@ public class CraftAttributeInstance implements AttributeInstance {
         return new AttributeModifier(nms.id(), nms.name, nms.amount(), AttributeModifier.Operation.values()[nms.operation().ordinal()]);
     }
 
-    public static AttributeModifier convert(net.minecraft.world.entity.ai.attributes.AttributeModifier nms, EquipmentSlot slot) {
-        return new AttributeModifier(nms.id(), nms.name, nms.amount(), AttributeModifier.Operation.values()[nms.operation().ordinal()], slot);
+    public static AttributeModifier convert(net.minecraft.world.entity.ai.attributes.AttributeModifier nms, net.minecraft.world.entity.EquipmentSlotGroup slot) { // Paper
+        return new AttributeModifier(nms.id(), nms.name, nms.amount(), AttributeModifier.Operation.values()[nms.operation().ordinal()], org.bukkit.craftbukkit.CraftEquipmentSlot.getSlot(slot)); // Paper
     }
 }
diff --git a/src/main/java/org/bukkit/craftbukkit/inventory/CraftItemType.java b/src/main/java/org/bukkit/craftbukkit/inventory/CraftItemType.java
index 1aa8010e872686f392430ce47214a324d431cada..6bcc3192097dfbf378592fd2437a80dcd0825f13 100644
--- a/src/main/java/org/bukkit/craftbukkit/inventory/CraftItemType.java
+++ b/src/main/java/org/bukkit/craftbukkit/inventory/CraftItemType.java
@@ -187,15 +187,34 @@ public class CraftItemType<M extends ItemMeta> implements ItemType.Typed<M>, Han
 //        return CraftEquipmentSlot.getSlot(EntityInsentient.getEquipmentSlotForItem(CraftItemStack.asNMSCopy(ItemStack.of(this))));
 //    }
 
+    // Paper start - improve default attribute API
+    @Override
+    public @NotNull Multimap<Attribute, AttributeModifier> getDefaultAttributeModifiers() {
+        return this.getDefaultAttributeModifiers(sg -> true);
+    }
+    // Paper end - improve default attribute API
+
     @Override
     public Multimap<Attribute, AttributeModifier> getDefaultAttributeModifiers(EquipmentSlot slot) {
-        ImmutableMultimap.Builder<Attribute, AttributeModifier> defaultAttributes = ImmutableMultimap.builder();
+        // Paper start - improve/fix item default attribute API
+        final net.minecraft.world.entity.EquipmentSlot nmsSlot = CraftEquipmentSlot.getNMS(slot);
+        return this.getDefaultAttributeModifiers(sg -> sg.test(nmsSlot));
+    }
 
-        ItemAttributeModifiers nmsDefaultAttributes = this.item.getDefaultAttributeModifiers();
-        nmsDefaultAttributes.forEach(CraftEquipmentSlot.getNMS(slot), (key, value) -> {
-            Attribute attribute = CraftAttribute.minecraftToBukkit(key.value());
-            defaultAttributes.put(attribute, CraftAttributeInstance.convert(value, slot));
-        });
+    private Multimap<Attribute, AttributeModifier> getDefaultAttributeModifiers(final java.util.function.Predicate<net.minecraft.world.entity.EquipmentSlotGroup> slotPredicate) {
+        final ImmutableMultimap.Builder<Attribute, AttributeModifier> defaultAttributes = ImmutableMultimap.builder();
+        ItemAttributeModifiers nmsDefaultAttributes = this.item.components().getOrDefault(DataComponents.ATTRIBUTE_MODIFIERS, ItemAttributeModifiers.EMPTY);
+        if (nmsDefaultAttributes.modifiers().isEmpty()) {
+            // we have to check both places cause for some reason vanilla puts default modifiers for armor in a different place
+            nmsDefaultAttributes = this.item.getDefaultAttributeModifiers();
+        }
+        for (final net.minecraft.world.item.component.ItemAttributeModifiers.Entry entry : nmsDefaultAttributes.modifiers()) {
+            if (!slotPredicate.test(entry.slot())) continue;
+            final Attribute attribute = CraftAttribute.minecraftHolderToBukkit(entry.attribute());
+            final AttributeModifier modifier = CraftAttributeInstance.convert(entry.modifier(), entry.slot());
+            defaultAttributes.put(attribute, modifier);
+        }
+        // Paper end - improve/fix item default attribute API
 
         return defaultAttributes.build();
     }
diff --git a/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java b/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
index 952a8147947fa0e2a960628fc760212d3d206ce6..f0577689f4c57ce6254aad32ccf5d8eac961c9bd 100644
--- a/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
+++ b/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
@@ -399,15 +399,11 @@ public final class CraftMagicNumbers implements UnsafeValues {
 
     @Override
     public Multimap<Attribute, AttributeModifier> getDefaultAttributeModifiers(Material material, EquipmentSlot slot) {
-        ImmutableMultimap.Builder<Attribute, AttributeModifier> defaultAttributes = ImmutableMultimap.builder();
-
-        ItemAttributeModifiers nmsDefaultAttributes = CraftMagicNumbers.getItem(material).getDefaultAttributeModifiers();
-        nmsDefaultAttributes.forEach(CraftEquipmentSlot.getNMS(slot), (key, value) -> {
-            Attribute attribute = CraftAttribute.minecraftToBukkit(key.value());
-            defaultAttributes.put(attribute, CraftAttributeInstance.convert(value, slot));
-        });
-
-        return defaultAttributes.build();
+        // Paper start - delegate to method on ItemType
+        final org.bukkit.inventory.ItemType item = material.asItemType();
+        Preconditions.checkArgument(item != null, material + " is not an item and does not have default attributes");
+        return item.getDefaultAttributeModifiers(slot);
+        // Paper end - delegate to method on ItemType
     }
 
     @Override