minecraft-src/net/minecraft/world/item/MaceItem.java

package net.minecraft.world.item;

import java.util.List;
import java.util.function.Predicate;
import net.minecraft.core.Direction;
import net.minecraft.network.protocol.game.ClientboundSetEntityMotionPacket;
import net.minecraft.server.level.ServerLevel;
import net.minecraft.server.level.ServerPlayer;
import net.minecraft.sounds.SoundEvent;
import net.minecraft.sounds.SoundEvents;
import net.minecraft.world.damagesource.DamageSource;
import net.minecraft.world.entity.Entity;
import net.minecraft.world.entity.EquipmentSlotGroup;
import net.minecraft.world.entity.LivingEntity;
import net.minecraft.world.entity.TamableAnimal;
import net.minecraft.world.entity.ai.attributes.AttributeModifier;
import net.minecraft.world.entity.ai.attributes.Attributes;
import net.minecraft.world.entity.decoration.ArmorStand;
import net.minecraft.world.item.component.ItemAttributeModifiers;
import net.minecraft.world.item.component.Tool;
import net.minecraft.world.item.enchantment.EnchantmentHelper;
import net.minecraft.world.level.Level;
import net.minecraft.world.phys.Vec3;
import org.jetbrains.annotations.Nullable;

public class MaceItem extends Item {
	private static final int DEFAULT_ATTACK_DAMAGE = 5;
	private static final float DEFAULT_ATTACK_SPEED = -3.4F;
	public static final float SMASH_ATTACK_FALL_THRESHOLD = 1.5F;
	private static final float SMASH_ATTACK_HEAVY_THRESHOLD = 5.0F;
	public static final float SMASH_ATTACK_KNOCKBACK_RADIUS = 3.5F;
	private static final float SMASH_ATTACK_KNOCKBACK_POWER = 0.7F;

	public MaceItem(Item.Properties properties) {
		super(properties);
	}

	public static ItemAttributeModifiers createAttributes() {
		return ItemAttributeModifiers.builder()
			.add(Attributes.ATTACK_DAMAGE, new AttributeModifier(BASE_ATTACK_DAMAGE_ID, 5.0, AttributeModifier.Operation.ADD_VALUE), EquipmentSlotGroup.MAINHAND)
			.add(Attributes.ATTACK_SPEED, new AttributeModifier(BASE_ATTACK_SPEED_ID, -3.4F, AttributeModifier.Operation.ADD_VALUE), EquipmentSlotGroup.MAINHAND)
			.build();
	}

	public static Tool createToolProperties() {
		return new Tool(List.of(), 1.0F, 2, false);
	}

	@Override
	public void hurtEnemy(ItemStack stack, LivingEntity target, LivingEntity attacker) {
		if (canSmashAttack(attacker)) {
			ServerLevel serverLevel = (ServerLevel)attacker.level();
			attacker.setDeltaMovement(attacker.getDeltaMovement().with(Direction.Axis.Y, 0.01F));
			if (attacker instanceof ServerPlayer serverPlayer) {
				serverPlayer.currentImpulseImpactPos = this.calculateImpactPosition(serverPlayer);
				serverPlayer.setIgnoreFallDamageFromCurrentImpulse(true);
				serverPlayer.connection.send(new ClientboundSetEntityMotionPacket(serverPlayer));
			}

			if (target.onGround()) {
				if (attacker instanceof ServerPlayer serverPlayer) {
					serverPlayer.setSpawnExtraParticlesOnFall(true);
				}

				SoundEvent soundEvent = attacker.fallDistance > 5.0 ? SoundEvents.MACE_SMASH_GROUND_HEAVY : SoundEvents.MACE_SMASH_GROUND;
				serverLevel.playSound(null, attacker.getX(), attacker.getY(), attacker.getZ(), soundEvent, attacker.getSoundSource(), 1.0F, 1.0F);
			} else {
				serverLevel.playSound(null, attacker.getX(), attacker.getY(), attacker.getZ(), SoundEvents.MACE_SMASH_AIR, attacker.getSoundSource(), 1.0F, 1.0F);
			}

			knockback(serverLevel, attacker, target);
		}
	}

	private Vec3 calculateImpactPosition(ServerPlayer player) {
		return player.isIgnoringFallDamageFromCurrentImpulse() && player.currentImpulseImpactPos != null && player.currentImpulseImpactPos.y <= player.position().y
			? player.currentImpulseImpactPos
			: player.position();
	}

	@Override
	public void postHurtEnemy(ItemStack stack, LivingEntity target, LivingEntity attacker) {
		if (canSmashAttack(attacker)) {
			attacker.resetFallDistance();
		}
	}

	@Override
	public float getAttackDamageBonus(Entity target, float damage, DamageSource damageSource) {
		if (damageSource.getDirectEntity() instanceof LivingEntity livingEntity) {
			if (!canSmashAttack(livingEntity)) {
				return 0.0F;
			} else {
				double d = 3.0;
				double e = 8.0;
				double f = livingEntity.fallDistance;
				double g;
				if (f <= 3.0) {
					g = 4.0 * f;
				} else if (f <= 8.0) {
					g = 12.0 + 2.0 * (f - 3.0);
				} else {
					g = 22.0 + f - 8.0;
				}

				return livingEntity.level() instanceof ServerLevel serverLevel
					? (float)(g + EnchantmentHelper.modifyFallBasedDamage(serverLevel, livingEntity.getWeaponItem(), target, damageSource, 0.0F) * f)
					: (float)g;
			}
		} else {
			return 0.0F;
		}
	}

	private static void knockback(Level level, Entity attacker, Entity target) {
		level.levelEvent(2013, target.getOnPos(), 750);
		level.getEntitiesOfClass(LivingEntity.class, target.getBoundingBox().inflate(3.5), knockbackPredicate(attacker, target)).forEach(livingEntity -> {
			Vec3 vec3 = livingEntity.position().subtract(target.position());
			double d = getKnockbackPower(attacker, livingEntity, vec3);
			Vec3 vec32 = vec3.normalize().scale(d);
			if (d > 0.0) {
				livingEntity.push(vec32.x, 0.7F, vec32.z);
				if (livingEntity instanceof ServerPlayer serverPlayer) {
					serverPlayer.connection.send(new ClientboundSetEntityMotionPacket(serverPlayer));
				}
			}
		});
	}

	private static Predicate<LivingEntity> knockbackPredicate(Entity attacker, Entity target) {
		return livingEntity -> {
			boolean bl = !livingEntity.isSpectator();
			boolean bl2 = livingEntity != attacker && livingEntity != target;
			boolean bl3 = !attacker.isAlliedTo(livingEntity);
			boolean bl4 = !(
				livingEntity instanceof TamableAnimal tamableAnimal
					&& target instanceof LivingEntity livingEntity2
					&& tamableAnimal.isTame()
					&& tamableAnimal.isOwnedBy(livingEntity2)
			);
			boolean bl5 = !(livingEntity instanceof ArmorStand armorStand && armorStand.isMarker());
			boolean bl6 = target.distanceToSqr(livingEntity) <= Math.pow(3.5, 2.0);
			return bl && bl2 && bl3 && bl4 && bl5 && bl6;
		};
	}

	private static double getKnockbackPower(Entity attacker, LivingEntity entity, Vec3 offset) {
		return (3.5 - offset.length()) * 0.7F * (attacker.fallDistance > 5.0 ? 2 : 1) * (1.0 - entity.getAttributeValue(Attributes.KNOCKBACK_RESISTANCE));
	}

	public static boolean canSmashAttack(LivingEntity entity) {
		return entity.fallDistance > 1.5 && !entity.isFallFlying();
	}

	@Nullable
	@Override
	public DamageSource getDamageSource(LivingEntity entity) {
		return canSmashAttack(entity) ? entity.damageSources().mace(entity) : super.getDamageSource(entity);
	}
}