Fix custom tools not receiving damage on entity attack

#565
xenondevs · Jan 20, 2025 · acbca23 · acbca23
1 parent 873caab
commit acbca23
Showing 1 changed file with 51 additions and 6 deletions.
diff --git a/nova/src/main/kotlin/xyz/xenondevs/nova/patch/impl/item/ToolPatches.kt b/nova/src/main/kotlin/xyz/xenondevs/nova/patch/impl/item/ToolPatches.kt
@@ -1,7 +1,11 @@
 package xyz.xenondevs.nova.patch.impl.item
 
+import net.minecraft.stats.Stats
 import net.minecraft.tags.ItemTags
 import net.minecraft.tags.TagKey
+import net.minecraft.world.entity.EquipmentSlot
+import net.minecraft.world.entity.LivingEntity
+import net.minecraft.world.entity.player.Player
 import net.minecraft.world.item.ItemStack
 import net.minecraft.world.level.block.state.BlockState
 import org.bukkit.craftbukkit.block.CraftBlock
@@ -18,18 +22,18 @@ import xyz.xenondevs.nova.util.item.novaItem
 import xyz.xenondevs.nova.util.item.takeUnlessEmpty
 import xyz.xenondevs.nova.util.reflection.ReflectionRegistry
 import xyz.xenondevs.nova.util.reflection.ReflectionUtils
+import xyz.xenondevs.nova.world.item.behavior.Damageable
 import xyz.xenondevs.nova.world.item.behavior.Tool
-import net.minecraft.world.entity.player.Player as MojangPlayer
-import net.minecraft.world.item.ItemStack as MojangStack
 
 private val ITEM_STACK_IS_TAG = ReflectionUtils.getMethod(ItemStack::class, "is", TagKey::class)
 
 @Suppress("unused")
-internal object ToolPatches : MultiTransformer(CraftBlock::class, MojangPlayer::class) {
+internal object ToolPatches : MultiTransformer(CraftBlock::class, Player::class, ItemStack::class) {
 
     override fun transform() {
         transformCraftBlockIsPreferredTool()
         transformPlayerAttack()
+        transformItemStackHurtEnemy()
     }
 
     /**
@@ -46,15 +50,15 @@ internal object ToolPatches : MultiTransformer(CraftBlock::class, MojangPlayer::
     }
 
     @JvmStatic
-    fun isPreferredTool(block: CraftBlock, blockState: BlockState, tool: MojangStack): Boolean {
+    fun isPreferredTool(block: CraftBlock, blockState: BlockState, tool: ItemStack): Boolean {
         return !blockState.requiresCorrectToolForDrops() || ToolUtils.isCorrectToolForDrops(block, tool.asBukkitMirror().takeUnlessEmpty())
     }
 
     /**
      * Patches the Player#attack method to use properly perform sweep attacks.
      */
     private fun transformPlayerAttack() {
-        VirtualClassPath[MojangPlayer::attack].replaceEvery(
+        VirtualClassPath[Player::attack].replaceEvery(
             0, 1,
             { invokeStatic(::canDoSweepAttack) },
             {
@@ -65,7 +69,7 @@ internal object ToolPatches : MultiTransformer(CraftBlock::class, MojangPlayer::
     }
 
     @JvmStatic
-    fun canDoSweepAttack(itemStack: MojangStack): Boolean {
+    fun canDoSweepAttack(itemStack: ItemStack): Boolean {
         val novaItem = itemStack.novaItem
 
         if (novaItem != null) {
@@ -75,4 +79,45 @@ internal object ToolPatches : MultiTransformer(CraftBlock::class, MojangPlayer::
         }
     }
 
+    /**
+     * Transforms ItemStack#hurtEnemy and ItemStack#postHurtEnemy to implement item damage on entity attack.
+     */
+    private fun transformItemStackHurtEnemy() {
+        // hurtEnemy needs to return true, otherwise postHurtEnemy is not called
+        VirtualClassPath[ItemStack::hurtEnemy].delegateStatic(::hurtEnemy)
+        VirtualClassPath[ItemStack::postHurtEnemy].delegateStatic(::postHurtEnemy)
+    }
+
+    @JvmStatic
+    fun hurtEnemy(itemStack: ItemStack, enemy: LivingEntity, attacker: LivingEntity): Boolean {
+        val novaItem = itemStack.novaItem
+        val isWeapon = if (novaItem != null) {
+            val damageable = novaItem.getBehaviorOrNull<Damageable>()
+                ?: return false
+            damageable.itemDamageOnAttackEntity > 0
+        } else {
+            itemStack.item.hurtEnemy(itemStack, enemy, attacker)
+        }
+
+        if (isWeapon && attacker is Player) {
+            attacker.awardStat(Stats.ITEM_USED.get(itemStack.item))
+        }
+
+        return isWeapon
+    }
+
+    @JvmStatic 
+    fun postHurtEnemy(itemStack: ItemStack, enemy: LivingEntity, attacker: LivingEntity) {
+        val novaItem = itemStack.novaItem
+
+        val damage: Int
+        if (novaItem != null) {
+            val damageable = novaItem.getBehaviorOrNull<Damageable>() ?: return
+            damage = damageable.itemDamageOnAttackEntity
+            itemStack.hurtAndBreak(damage, attacker, EquipmentSlot.MAINHAND)
+        } else {
+            itemStack.item.postHurtEnemy(itemStack, enemy, attacker)
+        }
+    }
+
 }