MinecraftForge/src/main/java/net/minecraftforge/event/AnvilUpdateEvent.java

/*
 * Copyright (c) Forge Development LLC and contributors
 * SPDX-License-Identifier: LGPL-2.1-only
 */

package net.minecraftforge.event;

import net.minecraft.world.entity.player.Player;
import net.minecraft.world.inventory.AnvilMenu;
import net.minecraft.world.item.ItemStack;
import net.minecraftforge.eventbus.api.Cancelable;
import net.minecraftforge.eventbus.api.Event;
import org.jetbrains.annotations.Nullable;

/**
 *
 * AnvilUpdateEvent is fired whenever the input stacks (left or right) or the name in an anvil changed. <br>
 * It is called from {@link AnvilMenu#createResult()}. <br>
 * If the event is canceled, vanilla behavior will not run, and the output will be set to {@link ItemStack#EMPTY}. <br>
 * If the event is not canceled, but the output is not empty, it will set the output and not run vanilla behavior. <br>
 * if the output is empty, and the event is not canceled, vanilla behavior will execute. <br>
 */
@Cancelable
public final class AnvilUpdateEvent extends Event {
    private final ItemStack left;
    private final ItemStack right;
    private final String name;
    private ItemStack output;
    private long cost;
    private int materialCost;
    private final Player player;

    public AnvilUpdateEvent(ItemStack left, ItemStack right, String name, long cost, Player player) {
        this.left = left;
        this.right = right;
        this.output = ItemStack.EMPTY;
        this.name = name;
        this.player = player;
        this.setCost(cost);
        this.setMaterialCost(0);
    }

    /**
     * @return The item in the left input (leftmost) anvil slot.
     */
    public ItemStack getLeft() {
        return left;
    }

    /**
     * @return The item in the right input (center) anvil slot.
     */
    public ItemStack getRight() {
        return right;
    }

    /**
     * This is the name as sent by the client.  It may be null if none has been sent. <br>
     * If empty, it indicates the user wishes to clear the custom name from the item.
     * @return The name that the output item will be set to, if applicable.
     */
    @Nullable
    public String getName() {
        return name;
    }

    /**
     * This is the output as determined by the event, not by the vanilla behavior between these two items. <br>
     * If you are the first receiver of this event, it is guaranteed to be empty. <br>
     * It will only be non-empty if changed by an event handler. <br>
     * If this event is cancelled, this output stack is discarded.
     * @return The item to set in the output (rightmost) anvil slot.
     */
    public ItemStack getOutput() {
        return output;
    }

    /**
     * Sets the output slot to a specific itemstack.
     * @param output The stack to change the output to.
     */
    public void setOutput(ItemStack output) {
        this.output = output;
    }

    /**
     * This is the level cost of this anvil operation. <br>
     * When unchanged, it is guaranteed to be left.getRepairCost() + right.getRepairCost().
     * @return The level cost of this anvil operation.
     */
    public long getCost() {
        return cost;
    }

    /**
     * Changes the level cost of this operation. <br>
     * The level cost does prevent the output from being available.  <br>
     * That is, a player without enough experience may not take the output.
     * @param cost The new level cost.
     */
    public void setCost(long cost) {
        this.cost = cost;
    }

    /**
     * The material cost is how many units of the right input stack are consumed.
     * @return The material cost of this anvil operation.
     */
    public int getMaterialCost() {
        return materialCost;
    }

    /**
     * Sets how many right inputs are consumed. <br>
     * A material cost of zero consumes the entire stack. <br>
     * A material cost higher than the count of the right stack
     * consumes the entire stack. <br>
     * The material cost does not prevent the output from being available.
     * @param materialCost The new material cost.
     */
    public void setMaterialCost(int materialCost) {
        this.materialCost = materialCost;
    }

    /**
     * @return The player using this anvil container.
     */
    public Player getPlayer() {
        return this.player;
    }
}