package net.minecraft.world;

import java.util.List;
import java.util.function.Predicate;
import net.minecraft.core.HolderLookup;
import net.minecraft.core.NonNullList;
import net.minecraft.nbt.CompoundTag;
import net.minecraft.nbt.ListTag;
import net.minecraft.world.item.ItemStack;

public class ContainerHelper {
	public static final String TAG_ITEMS = "Items";

	public static ItemStack removeItem(List<ItemStack> stacks, int index, int amount) {
		return index >= 0 && index < stacks.size() && !((ItemStack)stacks.get(index)).isEmpty() && amount > 0
			? ((ItemStack)stacks.get(index)).split(amount)
			: ItemStack.EMPTY;
	}

	public static ItemStack takeItem(List<ItemStack> stacks, int index) {
		return index >= 0 && index < stacks.size() ? (ItemStack)stacks.set(index, ItemStack.EMPTY) : ItemStack.EMPTY;
	}

	public static CompoundTag saveAllItems(CompoundTag tag, NonNullList<ItemStack> items, HolderLookup.Provider levelRegistry) {
		return saveAllItems(tag, items, true, levelRegistry);
	}

	public static CompoundTag saveAllItems(CompoundTag tag, NonNullList<ItemStack> items, boolean alwaysPutTag, HolderLookup.Provider levelRegistry) {
		ListTag listTag = new ListTag();

		for (int i = 0; i < items.size(); i++) {
			ItemStack itemStack = items.get(i);
			if (!itemStack.isEmpty()) {
				CompoundTag compoundTag = new CompoundTag();
				compoundTag.putByte("Slot", (byte)i);
				listTag.add(itemStack.save(levelRegistry, compoundTag));
			}
		}

		if (!listTag.isEmpty() || alwaysPutTag) {
			tag.put("Items", listTag);
		}

		return tag;
	}

	public static void loadAllItems(CompoundTag tag, NonNullList<ItemStack> items, HolderLookup.Provider levelRegistry) {
		ListTag listTag = tag.getListOrEmpty("Items");

		for (int i = 0; i < listTag.size(); i++) {
			CompoundTag compoundTag = listTag.getCompoundOrEmpty(i);
			int j = compoundTag.getByteOr("Slot", (byte)0) & 255;
			if (j >= 0 && j < items.size()) {
				items.set(j, (ItemStack)ItemStack.parse(levelRegistry, compoundTag).orElse(ItemStack.EMPTY));
			}
		}
	}

	/**
	 * Clears items from the inventory matching a predicate.
	 * @return The amount of items cleared
	 * 
	 * @param maxItems The maximum amount of items to be cleared. A negative value means unlimited and 0 means count how many items are found that could be cleared.
	 */
	public static int clearOrCountMatchingItems(Container container, Predicate<ItemStack> itemPredicate, int maxItems, boolean simulate) {
		int i = 0;

		for (int j = 0; j < container.getContainerSize(); j++) {
			ItemStack itemStack = container.getItem(j);
			int k = clearOrCountMatchingItems(itemStack, itemPredicate, maxItems - i, simulate);
			if (k > 0 && !simulate && itemStack.isEmpty()) {
				container.setItem(j, ItemStack.EMPTY);
			}

			i += k;
		}

		return i;
	}

	public static int clearOrCountMatchingItems(ItemStack stack, Predicate<ItemStack> itemPredicate, int maxItems, boolean simulate) {
		if (stack.isEmpty() || !itemPredicate.test(stack)) {
			return 0;
		} else if (simulate) {
			return stack.getCount();
		} else {
			int i = maxItems < 0 ? stack.getCount() : Math.min(maxItems, stack.getCount());
			stack.shrink(i);
			return i;
		}
	}
}