Upstream Paper

src/main/java/net/minecraft/server/EnchantmentThorns.java

@@ -0,0 +1,52 @@
+package net.minecraft.server;
+
+import java.util.Random;
+
+public class EnchantmentThorns extends Enchantment {
+
+    public EnchantmentThorns(Enchantment.Rarity enchantment_rarity, EnumItemSlot... aenumitemslot) {
+        super(enchantment_rarity, EnchantmentSlotType.ARMOR_CHEST, aenumitemslot);
+    }
+
+    public int a(int i) {
+        return 10 + 20 * (i - 1);
+    }
+
+    public int b(int i) {
+        return super.a(i) + 50;
+    }
+
+    public int getMaxLevel() {
+        return 3;
+    }
+
+    public boolean canEnchant(ItemStack itemstack) {
+        return itemstack.getItem() instanceof ItemArmor ? true : super.canEnchant(itemstack);
+    }
+
+    public void b(EntityLiving entityliving, Entity entity, int i) {
+        Random random = entityliving.getRandom();
+        ItemStack itemstack = EnchantmentManager.b(Enchantments.THORNS, entityliving);
+
+        if (entity != null && a(i, random)) { // CraftBukkit
+            if (entity != null) {
+                entity.damageEntity(DamageSource.a(entityliving), (float) b(i, random));
+            }
+
+            if (!itemstack.isEmpty()) {
+                itemstack.damage(3, entityliving);
+            }
+        } else if (!itemstack.isEmpty()) {
+            itemstack.damage(1, entityliving);
+        }
+
+    }
+
+    public static boolean a(int i, Random random) {
+        return i <= 0 ? false : random.nextFloat() < 0.15F * (float) i;
+    }
+
+    public static int b(int i, Random random) {
+        return i > 10 ? i - 10 : 1 + random.nextInt(4);
+    }
+}