Code/net/minecraft/world/item/ProjectileWeaponItem.java

package net.minecraft.world.item;

import java.util.ArrayList;
import java.util.List;
import java.util.function.Predicate;
import javax.annotation.Nullable;
import net.minecraft.core.component.DataComponents;
import net.minecraft.server.level.ServerLevel;
import net.minecraft.tags.ItemTags;
import net.minecraft.util.Unit;
import net.minecraft.world.InteractionHand;
import net.minecraft.world.entity.LivingEntity;
import net.minecraft.world.entity.player.Player;
import net.minecraft.world.entity.projectile.AbstractArrow;
import net.minecraft.world.entity.projectile.Projectile;
import net.minecraft.world.item.enchantment.EnchantmentHelper;
import net.minecraft.world.level.Level;

public abstract class ProjectileWeaponItem extends Item {
    public static final Predicate<ItemStack> ARROW_ONLY = p_43017_ -> p_43017_.is(ItemTags.ARROWS);
    public static final Predicate<ItemStack> ARROW_OR_FIREWORK = ARROW_ONLY.or(p_43015_ -> p_43015_.is(Items.FIREWORK_ROCKET));

    public ProjectileWeaponItem(Item.Properties p_43009_) {
        super(p_43009_);
    }

    public Predicate<ItemStack> getSupportedHeldProjectiles() {
        return this.getAllSupportedProjectiles();
    }

    public abstract Predicate<ItemStack> getAllSupportedProjectiles();

    public static ItemStack getHeldProjectile(LivingEntity p_43011_, Predicate<ItemStack> p_43012_) {
        if (p_43012_.test(p_43011_.getItemInHand(InteractionHand.OFF_HAND))) {
            return p_43011_.getItemInHand(InteractionHand.OFF_HAND);
        } else {
            return p_43012_.test(p_43011_.getItemInHand(InteractionHand.MAIN_HAND)) ? p_43011_.getItemInHand(InteractionHand.MAIN_HAND) : ItemStack.EMPTY;
        }
    }

    public abstract int getDefaultProjectileRange();

    protected void shoot(
        ServerLevel p_344476_,
        LivingEntity p_332682_,
        InteractionHand p_333462_,
        ItemStack p_333670_,
        List<ItemStack> p_328443_,
        float p_330956_,
        float p_333326_,
        boolean p_332457_,
        @Nullable LivingEntity p_328954_
    ) {
        float f = EnchantmentHelper.processProjectileSpread(p_344476_, p_333670_, p_332682_, 0.0F);
        float f1 = p_328443_.size() == 1 ? 0.0F : 2.0F * f / (p_328443_.size() - 1);
        float f2 = (p_328443_.size() - 1) % 2 * f1 / 2.0F;
        float f3 = 1.0F;

        for (int i = 0; i < p_328443_.size(); i++) {
            ItemStack itemstack = p_328443_.get(i);
            if (!itemstack.isEmpty()) {
                float f4 = f2 + f3 * ((i + 1) / 2) * f1;
                f3 = -f3;
                int j = i;
                Projectile.spawnProjectile(
                    this.createProjectile(p_344476_, p_332682_, p_333670_, itemstack, p_332457_),
                    p_344476_,
                    itemstack,
                    p_359794_ -> this.shootProjectile(p_332682_, p_359794_, j, p_330956_, p_333326_, f4, p_328954_)
                );
                p_333670_.hurtAndBreak(this.getDurabilityUse(itemstack), p_332682_, LivingEntity.getSlotForHand(p_333462_));
                if (p_333670_.isEmpty()) {
                    break;
                }
            }
        }
    }

    protected int getDurabilityUse(ItemStack p_330687_) {
        return 1;
    }

    protected abstract void shootProjectile(
        LivingEntity p_330864_, Projectile p_328720_, int p_328740_, float p_335337_, float p_332934_, float p_329948_, @Nullable LivingEntity p_329516_
    );

    protected Projectile createProjectile(Level p_333069_, LivingEntity p_334736_, ItemStack p_333680_, ItemStack p_329118_, boolean p_336242_) {
        ArrowItem arrowitem = p_329118_.getItem() instanceof ArrowItem arrowitem1 ? arrowitem1 : (ArrowItem)Items.ARROW;
        AbstractArrow abstractarrow = arrowitem.createArrow(p_333069_, p_329118_, p_334736_, p_333680_);
        if (p_336242_) {
            abstractarrow.setCritArrow(true);
        }

        return abstractarrow;
    }

    protected static List<ItemStack> draw(ItemStack p_329054_, ItemStack p_328618_, LivingEntity p_335616_) {
        if (p_328618_.isEmpty()) {
            return List.of();
        } else {
            int i = p_335616_.level() instanceof ServerLevel serverlevel ? EnchantmentHelper.processProjectileCount(serverlevel, p_329054_, p_335616_, 1) : 1;
            List<ItemStack> list = new ArrayList<>(i);
            ItemStack itemstack1 = p_328618_.copy();

            for (int j = 0; j < i; j++) {
                ItemStack itemstack = useAmmo(p_329054_, j == 0 ? p_328618_ : itemstack1, p_335616_, j > 0);
                if (!itemstack.isEmpty()) {
                    list.add(itemstack);
                }
            }

            return list;
        }
    }

    protected static ItemStack useAmmo(ItemStack p_335938_, ItemStack p_332014_, LivingEntity p_332327_, boolean p_327685_) {
        int i = !p_327685_ && !p_332327_.hasInfiniteMaterials() && p_332327_.level() instanceof ServerLevel serverlevel
            ? EnchantmentHelper.processAmmoUse(serverlevel, p_335938_, p_332014_, 1)
            : 0;
        if (i > p_332014_.getCount()) {
            return ItemStack.EMPTY;
        } else if (i == 0) {
            ItemStack itemstack1 = p_332014_.copyWithCount(1);
            itemstack1.set(DataComponents.INTANGIBLE_PROJECTILE, Unit.INSTANCE);
            return itemstack1;
        } else {
            ItemStack itemstack = p_332014_.split(i);
            if (p_332014_.isEmpty() && p_332327_ instanceof Player player) {
                player.getInventory().removeItem(p_332014_);
            }

            return itemstack;
        }
    }
}