Minestom/src/main/java/net/minestom/server/item/ItemStack.java

package net.minestom.server.item;

import net.kyori.adventure.nbt.api.BinaryTagHolder;
import net.kyori.adventure.text.Component;
import net.kyori.adventure.text.event.HoverEvent;
import net.kyori.adventure.text.event.HoverEventSource;
import net.minestom.server.adventure.MinestomAdventure;
import net.minestom.server.inventory.ContainerInventory;
import net.minestom.server.tag.Tag;
import net.minestom.server.tag.TagHandler;
import net.minestom.server.tag.TagReadable;
import net.minestom.server.tag.TagWritable;
import net.minestom.server.utils.validate.Check;
import org.jetbrains.annotations.*;
import org.jglrxavpok.hephaistos.nbt.NBTCompound;

import java.util.List;
import java.util.function.Consumer;
import java.util.function.IntUnaryOperator;
import java.util.function.UnaryOperator;

/**
 * Represents an immutable item to be placed inside {@link net.minestom.server.inventory.PlayerInventory},
 * {@link ContainerInventory} or even on the ground {@link net.minestom.server.entity.ItemEntity}.
 * <p>
 * An item stack cannot be null, {@link ItemStack#AIR} should be used instead.
 */
public sealed interface ItemStack extends TagReadable, HoverEventSource<HoverEvent.ShowItem>
        permits ItemStackImpl {
    /**
     * Constant AIR item. Should be used instead of 'null'.
     */
    @NotNull ItemStack AIR = ItemStack.of(Material.AIR);

    @Contract(value = "_ -> new", pure = true)
    static @NotNull Builder builder(@NotNull Material material) {
        return new ItemStackImpl.Builder(material, 1);
    }

    @Contract(value = "_ ,_ -> new", pure = true)
    static @NotNull ItemStack of(@NotNull Material material, int amount) {
        return ItemStackImpl.create(material, amount);
    }

    @Contract(value = "_ -> new", pure = true)
    static @NotNull ItemStack of(@NotNull Material material) {
        return of(material, 1);
    }

    @Contract(value = "_, _, _ -> new", pure = true)
    static @NotNull ItemStack fromNBT(@NotNull Material material, @Nullable NBTCompound nbtCompound, int amount) {
        if (nbtCompound == null) return of(material, amount);
        return builder(material).amount(amount).meta(nbtCompound).build();
    }

    @Contract(value = "_, _ -> new", pure = true)
    static @NotNull ItemStack fromNBT(@NotNull Material material, @Nullable NBTCompound nbtCompound) {
        return fromNBT(material, nbtCompound, 1);
    }

    /**
     * Converts this item to an NBT tag containing the id (material), count (amount), and tag (meta).
     *
     * @param nbtCompound The nbt representation of the item
     */
    @ApiStatus.Experimental
    static @NotNull ItemStack fromItemNBT(@NotNull NBTCompound nbtCompound) {
        String id = nbtCompound.getString("id");
        Check.notNull(id, "Item NBT must contain an id field.");
        Material material = Material.fromNamespaceId(id);
        Check.notNull(material, "Unknown material: {0}", id);

        Byte amount = nbtCompound.getByte("Count");
        if (amount == null) amount = 1;
        final NBTCompound tag = nbtCompound.getCompound("tag");
        return tag != null ? fromNBT(material, tag, amount) : of(material, amount);
    }

    @Contract(pure = true)
    @NotNull Material material();

    @Contract(pure = true)
    int amount();

    @Contract(pure = true)
    @NotNull ItemMeta meta();

    @Contract(pure = true)
    @ApiStatus.Experimental
    <T extends ItemMetaView<?>> @NotNull T meta(@NotNull Class<T> metaClass);

    @Contract(value = "_, -> new", pure = true)
    @NotNull ItemStack with(@NotNull Consumer<@NotNull Builder> consumer);

    @Contract(value = "_, _ -> new", pure = true)
    @ApiStatus.Experimental
    <V extends ItemMetaView.Builder, T extends ItemMetaView<V>> @NotNull ItemStack withMeta(@NotNull Class<T> metaType,
                                                                                            @NotNull Consumer<V> consumer);

    @Contract(value = "_ -> new", pure = true)
    @NotNull ItemStack withMeta(@NotNull Consumer<ItemMeta.@NotNull Builder> consumer);

    @Contract(value = "_, -> new", pure = true)
    @NotNull ItemStack withMaterial(@NotNull Material material);

    @Contract(value = "_, -> new", pure = true)
    @NotNull ItemStack withAmount(int amount);

    @Contract(value = "_, -> new", pure = true)
    default @NotNull ItemStack withAmount(@NotNull IntUnaryOperator intUnaryOperator) {
        return withAmount(intUnaryOperator.applyAsInt(amount()));
    }

    @ApiStatus.Experimental
    @Contract(value = "_, -> new", pure = true)
    @NotNull ItemStack consume(int amount);

    @Contract(pure = true)
    default @Nullable Component getDisplayName() {
        return meta().getDisplayName();
    }

    @Contract(pure = true)
    default @NotNull List<@NotNull Component> getLore() {
        return meta().getLore();
    }

    @ApiStatus.Experimental
    @Contract(value = "_ -> new", pure = true)
    @NotNull ItemStack withMeta(@NotNull ItemMeta meta);

    @Contract(value = "_, -> new", pure = true)
    default @NotNull ItemStack withDisplayName(@Nullable Component displayName) {
        return withMeta(builder -> builder.displayName(displayName));
    }

    @Contract(value = "_, -> new", pure = true)
    default @NotNull ItemStack withDisplayName(@NotNull UnaryOperator<@Nullable Component> componentUnaryOperator) {
        return withDisplayName(componentUnaryOperator.apply(getDisplayName()));
    }

    @Contract(value = "_, -> new", pure = true)
    default @NotNull ItemStack withLore(@NotNull List<? extends Component> lore) {
        return withMeta(builder -> builder.lore(lore));
    }

    @Contract(value = "_, -> new", pure = true)
    default @NotNull ItemStack withLore(@NotNull UnaryOperator<@NotNull List<@NotNull Component>> loreUnaryOperator) {
        return withLore(loreUnaryOperator.apply(getLore()));
    }

    @Contract(pure = true)
    default boolean isAir() {
        return material() == Material.AIR;
    }

    @Contract(pure = true)
    boolean isSimilar(@NotNull ItemStack itemStack);

    @Contract(value = "_, _ -> new", pure = true)
    default <T> @NotNull ItemStack withTag(@NotNull Tag<T> tag, @Nullable T value) {
        return withMeta(builder -> builder.set(tag, value));
    }

    @Override
    default <T> @UnknownNullability T getTag(@NotNull Tag<T> tag) {
        return meta().getTag(tag);
    }

    @Override
    default @NotNull HoverEvent<HoverEvent.ShowItem> asHoverEvent(@NotNull UnaryOperator<HoverEvent.ShowItem> op) {
        final BinaryTagHolder tagHolder = BinaryTagHolder.encode(meta().toNBT(), MinestomAdventure.NBT_CODEC);
        return HoverEvent.showItem(op.apply(HoverEvent.ShowItem.showItem(material(), amount(), tagHolder)));
    }

    /**
     * Converts this item to an NBT tag containing the id (material), count (amount), and tag (meta)
     *
     * @return The nbt representation of the item
     */
    @ApiStatus.Experimental
    @NotNull NBTCompound toItemNBT();


    @Deprecated
    @Contract(pure = true)
    default @NotNull Material getMaterial() {
        return material();
    }

    @Deprecated
    @Contract(pure = true)
    default int getAmount() {
        return amount();
    }

    @Deprecated
    @Contract(pure = true)
    default @NotNull ItemMeta getMeta() {
        return meta();
    }

    sealed interface Builder extends TagWritable
            permits ItemStackImpl.Builder {
        @Contract(value = "_ -> this")
        @NotNull Builder amount(int amount);

        @Contract(value = "_ -> this")
        @NotNull Builder meta(@NotNull TagHandler tagHandler);

        @Contract(value = "_ -> this")
        @NotNull Builder meta(@NotNull NBTCompound compound);

        @Contract(value = "_ -> this")
        @NotNull Builder meta(@NotNull ItemMeta itemMeta);

        @Contract(value = "_ -> this")
        @NotNull Builder meta(@NotNull Consumer<ItemMeta.@NotNull Builder> consumer);

        @Contract(value = "_, _ -> this")
        <V extends ItemMetaView.Builder, T extends ItemMetaView<V>> @NotNull Builder meta(@NotNull Class<T> metaType,
                                                                                          @NotNull Consumer<@NotNull V> itemMetaConsumer);

        @Contract(value = "-> new", pure = true)
        @NotNull ItemStack build();

        @Contract(value = "_, _ -> this")
        default <T> @NotNull Builder set(@NotNull Tag<T> tag, @Nullable T value) {
            setTag(tag, value);
            return this;
        }

        @Contract(value = "_ -> this")
        default @NotNull Builder displayName(@Nullable Component displayName) {
            return meta(builder -> builder.displayName(displayName));
        }

        @Contract(value = "_ -> this")
        default @NotNull Builder lore(@NotNull List<? extends Component> lore) {
            return meta(builder -> builder.lore(lore));
        }

        @Contract(value = "_ -> this")
        default @NotNull Builder lore(Component... lore) {
            return meta(builder -> builder.lore(lore));
        }
    }
}