More Enchantment API

== AT ==
public net.minecraft.world.item.enchantment.Enchantment definition

Co-authored-by: Luis <luisc99@icloud.com>
Co-authored-by: Janet Blackquill <uhhadd@gmail.com>

paper-server/src/main/java/org/bukkit/craftbukkit/enchantments/CraftEnchantment.java

@@ -5,6 +5,7 @@ import java.util.Locale;
 import net.minecraft.Util;
 import net.minecraft.core.Holder;
 import net.minecraft.core.registries.Registries;
+import net.minecraft.network.chat.contents.TranslatableContents;
 import net.minecraft.tags.EnchantmentTags;
 import org.bukkit.NamespacedKey;
 import org.bukkit.Registry;
@@ -90,7 +91,7 @@ public class CraftEnchantment extends Enchantment implements Handleable<net.mine
 
     @Override
     public boolean isTreasure() {
-        return !this.handle.is(EnchantmentTags.IN_ENCHANTING_TABLE);
+        return this.handle.is(EnchantmentTags.TREASURE); // Paper - use treasure tag
     }
 
     @Override
@@ -148,7 +149,7 @@ public class CraftEnchantment extends Enchantment implements Handleable<net.mine
     // Paper start
     @Override
     public net.kyori.adventure.text.Component displayName(int level) {
-        return io.papermc.paper.adventure.PaperAdventure.asAdventure(getHandle().getFullname(level));
+        return io.papermc.paper.adventure.PaperAdventure.asAdventure(net.minecraft.world.item.enchantment.Enchantment.getFullname(this.handle, level));
     }
     // Paper end
 
@@ -159,10 +160,62 @@ public class CraftEnchantment extends Enchantment implements Handleable<net.mine
             throw new UnsupportedOperationException("Description isn't translatable!"); // Paper
         }
         return translatableContents.getKey();
-
     }
     // Paper end - add translationKey methods
 
+    // Paper start - more Enchantment API
+    @Override
+    public boolean isTradeable() {
+        return this.handle.is(EnchantmentTags.TRADEABLE);
+    }
+
+    @Override
+    public boolean isDiscoverable() {
+        return this.handle.is(EnchantmentTags.IN_ENCHANTING_TABLE)
+            || this.handle.is(EnchantmentTags.ON_RANDOM_LOOT)
+            || this.handle.is(EnchantmentTags.ON_MOB_SPAWN_EQUIPMENT)
+            || this.handle.is(EnchantmentTags.TRADEABLE)
+            || this.handle.is(EnchantmentTags.ON_TRADED_EQUIPMENT);
+    }
+
+    @Override
+    public int getMinModifiedCost(int level) {
+        return this.getHandle().definition().minCost().calculate(level);
+    }
+
+    @Override
+    public int getMaxModifiedCost(int level) {
+        return this.getHandle().definition().maxCost().calculate(level);
+    }
+
+    @Override
+    public int getAnvilCost() {
+        return this.getHandle().definition().anvilCost();
+    }
+
+    @Override
+    public io.papermc.paper.enchantments.EnchantmentRarity getRarity() {
+        throw new UnsupportedOperationException("Enchantments don't have a rarity anymore in 1.20.5+.");
+    }
+
+    @Override
+    public float getDamageIncrease(int level, org.bukkit.entity.EntityCategory entityCategory) {
+        throw new UnsupportedOperationException("Enchantments are based on complex effect maps since 1.21, cannot compute a simple damage increase");
+    }
+
+    @Override
+    public float getDamageIncrease(int level, org.bukkit.entity.EntityType entityType) {
+        throw new UnsupportedOperationException("Enchantments are based on complex effect maps since 1.21, cannot compute a simple damage increase");
+    }
+
+    @Override
+    public java.util.Set<org.bukkit.inventory.EquipmentSlotGroup> getActiveSlotGroups() {
+        return this.getHandle().definition().slots().stream()
+            .map(org.bukkit.craftbukkit.CraftEquipmentSlot::getSlot)
+            .collect(java.util.stream.Collectors.toSet());
+    }
+    // Paper end - more Enchantment API
+
     @Override
     public String getTranslationKey() {
         return Util.makeDescriptionId("enchantment", this.handle.unwrapKey().get().location());