Code/net/minecraft/world/item/trading/MerchantOffer.java

package net.minecraft.world.item.trading;

import com.mojang.serialization.Codec;
import com.mojang.serialization.codecs.RecordCodecBuilder;
import com.mojang.serialization.codecs.RecordCodecBuilder.Instance;
import java.util.Optional;
import net.minecraft.network.RegistryFriendlyByteBuf;
import net.minecraft.network.codec.StreamCodec;
import net.minecraft.util.Mth;
import net.minecraft.world.item.ItemStack;

public class MerchantOffer {
    public static final Codec<MerchantOffer> CODEC = RecordCodecBuilder.create(
        p_327696_ -> p_327696_.group(
                ItemCost.CODEC.fieldOf("buy").forGetter(p_328146_ -> p_328146_.baseCostA),
                ItemCost.CODEC.lenientOptionalFieldOf("buyB").forGetter(p_329936_ -> p_329936_.costB),
                ItemStack.CODEC.fieldOf("sell").forGetter(p_330911_ -> p_330911_.result),
                Codec.INT.lenientOptionalFieldOf("uses", 0).forGetter(p_329708_ -> p_329708_.uses),
                Codec.INT.lenientOptionalFieldOf("maxUses", 4).forGetter(p_334393_ -> p_334393_.maxUses),
                Codec.BOOL.lenientOptionalFieldOf("rewardExp", true).forGetter(p_334163_ -> p_334163_.rewardExp),
                Codec.INT.lenientOptionalFieldOf("specialPrice", 0).forGetter(p_331018_ -> p_331018_.specialPriceDiff),
                Codec.INT.lenientOptionalFieldOf("demand", 0).forGetter(p_334425_ -> p_334425_.demand),
                Codec.FLOAT.lenientOptionalFieldOf("priceMultiplier", 0.0F).forGetter(p_335604_ -> p_335604_.priceMultiplier),
                Codec.INT.lenientOptionalFieldOf("xp", 1).forGetter(p_334362_ -> p_334362_.xp)
            )
            .apply(p_327696_, MerchantOffer::new)
    );
    public static final StreamCodec<RegistryFriendlyByteBuf, MerchantOffer> STREAM_CODEC = StreamCodec.of(
        MerchantOffer::writeToStream, MerchantOffer::createFromStream
    );
    private final ItemCost baseCostA;
    private final Optional<ItemCost> costB;
    private final ItemStack result;
    private int uses;
    private final int maxUses;
    private final boolean rewardExp;
    private int specialPriceDiff;
    private int demand;
    private final float priceMultiplier;
    private final int xp;

    private MerchantOffer(
        ItemCost p_329205_,
        Optional<ItemCost> p_330242_,
        ItemStack p_45334_,
        int p_45337_,
        int p_45338_,
        boolean p_336032_,
        int p_45339_,
        int p_335600_,
        float p_45340_,
        int p_332893_
    ) {
        this.baseCostA = p_329205_;
        this.costB = p_330242_;
        this.result = p_45334_;
        this.uses = p_45337_;
        this.maxUses = p_45338_;
        this.rewardExp = p_336032_;
        this.specialPriceDiff = p_45339_;
        this.demand = p_335600_;
        this.priceMultiplier = p_45340_;
        this.xp = p_332893_;
    }

    public MerchantOffer(ItemCost p_329227_, ItemStack p_45327_, int p_45330_, int p_45331_, float p_45332_) {
        this(p_329227_, Optional.empty(), p_45327_, p_45330_, p_45331_, p_45332_);
    }

    public MerchantOffer(ItemCost p_329055_, Optional<ItemCost> p_335735_, ItemStack p_45321_, int p_45323_, int p_45324_, float p_45325_) {
        this(p_329055_, p_335735_, p_45321_, 0, p_45323_, p_45324_, p_45325_);
    }

    public MerchantOffer(ItemCost p_335696_, Optional<ItemCost> p_334891_, ItemStack p_45342_, int p_45345_, int p_45346_, int p_45347_, float p_45348_) {
        this(p_335696_, p_334891_, p_45342_, p_45345_, p_45346_, p_45347_, p_45348_, 0);
    }

    public MerchantOffer(
        ItemCost p_330366_, Optional<ItemCost> p_332494_, ItemStack p_335597_, int p_333040_, int p_328201_, int p_334322_, float p_333357_, int p_332973_
    ) {
        this(p_330366_, p_332494_, p_335597_, p_333040_, p_328201_, true, 0, p_332973_, p_333357_, p_334322_);
    }

    private MerchantOffer(MerchantOffer p_301741_) {
        this(
            p_301741_.baseCostA,
            p_301741_.costB,
            p_301741_.result.copy(),
            p_301741_.uses,
            p_301741_.maxUses,
            p_301741_.rewardExp,
            p_301741_.specialPriceDiff,
            p_301741_.demand,
            p_301741_.priceMultiplier,
            p_301741_.xp
        );
    }

    public ItemStack getBaseCostA() {
        return this.baseCostA.itemStack();
    }

    public ItemStack getCostA() {
        return this.baseCostA.itemStack().copyWithCount(this.getModifiedCostCount(this.baseCostA));
    }

    private int getModifiedCostCount(ItemCost p_330475_) {
        int i = p_330475_.count();
        int j = Math.max(0, Mth.floor(i * this.demand * this.priceMultiplier));
        return Mth.clamp(i + j + this.specialPriceDiff, 1, p_330475_.itemStack().getMaxStackSize());
    }

    public ItemStack getCostB() {
        return this.costB.map(ItemCost::itemStack).orElse(ItemStack.EMPTY);
    }

    public ItemCost getItemCostA() {
        return this.baseCostA;
    }

    public Optional<ItemCost> getItemCostB() {
        return this.costB;
    }

    public ItemStack getResult() {
        return this.result;
    }

    public void updateDemand() {
        this.demand = this.demand + this.uses - (this.maxUses - this.uses);
    }

    public ItemStack assemble() {
        return this.result.copy();
    }

    public int getUses() {
        return this.uses;
    }

    public void resetUses() {
        this.uses = 0;
    }

    public int getMaxUses() {
        return this.maxUses;
    }

    public void increaseUses() {
        this.uses++;
    }

    public int getDemand() {
        return this.demand;
    }

    public void addToSpecialPriceDiff(int p_45354_) {
        this.specialPriceDiff += p_45354_;
    }

    public void resetSpecialPriceDiff() {
        this.specialPriceDiff = 0;
    }

    public int getSpecialPriceDiff() {
        return this.specialPriceDiff;
    }

    public void setSpecialPriceDiff(int p_45360_) {
        this.specialPriceDiff = p_45360_;
    }

    public float getPriceMultiplier() {
        return this.priceMultiplier;
    }

    public int getXp() {
        return this.xp;
    }

    public boolean isOutOfStock() {
        return this.uses >= this.maxUses;
    }

    public void setToOutOfStock() {
        this.uses = this.maxUses;
    }

    public boolean needsRestock() {
        return this.uses > 0;
    }

    public boolean shouldRewardExp() {
        return this.rewardExp;
    }

    public boolean satisfiedBy(ItemStack p_45356_, ItemStack p_45357_) {
        if (!this.baseCostA.test(p_45356_) || p_45356_.getCount() < this.getModifiedCostCount(this.baseCostA)) {
            return false;
        } else {
            return !this.costB.isPresent()
                ? p_45357_.isEmpty()
                : this.costB.get().test(p_45357_) && p_45357_.getCount() >= this.costB.get().count();
        }
    }

    public boolean take(ItemStack p_45362_, ItemStack p_45363_) {
        if (!this.satisfiedBy(p_45362_, p_45363_)) {
            return false;
        } else {
            p_45362_.shrink(this.getCostA().getCount());
            if (!this.getCostB().isEmpty()) {
                p_45363_.shrink(this.getCostB().getCount());
            }

            return true;
        }
    }

    public MerchantOffer copy() {
        return new MerchantOffer(this);
    }

    private static void writeToStream(RegistryFriendlyByteBuf p_331919_, MerchantOffer p_333750_) {
        ItemCost.STREAM_CODEC.encode(p_331919_, p_333750_.getItemCostA());
        ItemStack.STREAM_CODEC.encode(p_331919_, p_333750_.getResult());
        ItemCost.OPTIONAL_STREAM_CODEC.encode(p_331919_, p_333750_.getItemCostB());
        p_331919_.writeBoolean(p_333750_.isOutOfStock());
        p_331919_.writeInt(p_333750_.getUses());
        p_331919_.writeInt(p_333750_.getMaxUses());
        p_331919_.writeInt(p_333750_.getXp());
        p_331919_.writeInt(p_333750_.getSpecialPriceDiff());
        p_331919_.writeFloat(p_333750_.getPriceMultiplier());
        p_331919_.writeInt(p_333750_.getDemand());
    }

    public static MerchantOffer createFromStream(RegistryFriendlyByteBuf p_335331_) {
        ItemCost itemcost = ItemCost.STREAM_CODEC.decode(p_335331_);
        ItemStack itemstack = ItemStack.STREAM_CODEC.decode(p_335331_);
        Optional<ItemCost> optional = ItemCost.OPTIONAL_STREAM_CODEC.decode(p_335331_);
        boolean flag = p_335331_.readBoolean();
        int i = p_335331_.readInt();
        int j = p_335331_.readInt();
        int k = p_335331_.readInt();
        int l = p_335331_.readInt();
        float f = p_335331_.readFloat();
        int i1 = p_335331_.readInt();
        MerchantOffer merchantoffer = new MerchantOffer(itemcost, optional, itemstack, i, j, k, f, i1);
        if (flag) {
            merchantoffer.setToOutOfStock();
        }

        merchantoffer.setSpecialPriceDiff(l);
        return merchantoffer;
    }
}