package net.minecraft.advancements.triggers;

import com.mojang.serialization.Codec;
import com.mojang.serialization.codecs.RecordCodecBuilder;
import it.unimi.dsi.fastutil.objects.ObjectArrayList;
import java.util.List;
import java.util.Optional;
import java.util.stream.Stream;
import net.minecraft.advancements.predicates.ContextAwarePredicate;
import net.minecraft.advancements.predicates.DataComponentMatchers;
import net.minecraft.advancements.predicates.ItemPredicate;
import net.minecraft.advancements.predicates.MinMaxBounds;
import net.minecraft.advancements.predicates.entity.EntityPredicate;
import net.minecraft.core.HolderSet;
import net.minecraft.server.level.ServerPlayer;
import net.minecraft.world.entity.player.Inventory;
import net.minecraft.world.item.ItemInstance;
import net.minecraft.world.item.ItemStack;
import net.minecraft.world.level.ItemLike;

public class InventoryChangeTrigger extends SimpleCriterionTrigger<InventoryChangeTrigger.TriggerInstance> {
	@Override
	public Codec<InventoryChangeTrigger.TriggerInstance> codec() {
		return InventoryChangeTrigger.TriggerInstance.CODEC;
	}

	public void trigger(final ServerPlayer player, final Inventory inventory, final ItemStack changedItem) {
		int slotsFull = 0;
		int slotsEmpty = 0;
		int slotsOccupied = 0;

		for (int slot = 0; slot < inventory.getContainerSize(); slot++) {
			ItemStack itemStack = inventory.getItem(slot);
			if (itemStack.isEmpty()) {
				slotsEmpty++;
			} else {
				slotsOccupied++;
				if (itemStack.getCount() >= itemStack.getMaxStackSize()) {
					slotsFull++;
				}
			}
		}

		this.trigger(player, inventory, changedItem, slotsFull, slotsEmpty, slotsOccupied);
	}

	private void trigger(
		final ServerPlayer player, final Inventory inventory, final ItemStack changedItem, final int slotsFull, final int slotsEmpty, final int slotsOccupied
	) {
		this.trigger(player, t -> t.matches(inventory, changedItem, slotsFull, slotsEmpty, slotsOccupied));
	}

	public record TriggerInstance(Optional<ContextAwarePredicate> player, InventoryChangeTrigger.TriggerInstance.Slots slots, List<ItemPredicate> items)
		implements SimpleCriterionTrigger.SimpleInstance {
		public static final Codec<InventoryChangeTrigger.TriggerInstance> CODEC = RecordCodecBuilder.create(
			i -> i.group(
					EntityPredicate.ADVANCEMENT_CODEC.optionalFieldOf("player").forGetter(InventoryChangeTrigger.TriggerInstance::player),
					InventoryChangeTrigger.TriggerInstance.Slots.CODEC
						.optionalFieldOf("slots", InventoryChangeTrigger.TriggerInstance.Slots.ANY)
						.forGetter(InventoryChangeTrigger.TriggerInstance::slots),
					ItemPredicate.CODEC.listOf().optionalFieldOf("items", List.of()).forGetter(InventoryChangeTrigger.TriggerInstance::items)
				)
				.apply(i, InventoryChangeTrigger.TriggerInstance::new)
		);

		public static Criterion<InventoryChangeTrigger.TriggerInstance> hasItems(final ItemPredicate.Builder... items) {
			return hasItems((ItemPredicate[])Stream.of(items).map(ItemPredicate.Builder::build).toArray(ItemPredicate[]::new));
		}

		public static Criterion<InventoryChangeTrigger.TriggerInstance> hasItems(final ItemPredicate... items) {
			return CriteriaTriggers.INVENTORY_CHANGED
				.createCriterion(new InventoryChangeTrigger.TriggerInstance(Optional.empty(), InventoryChangeTrigger.TriggerInstance.Slots.ANY, List.of(items)));
		}

		public static Criterion<InventoryChangeTrigger.TriggerInstance> hasItems(final ItemLike... items) {
			ItemPredicate[] predicates = new ItemPredicate[items.length];

			for (int i = 0; i < items.length; i++) {
				predicates[i] = new ItemPredicate(
					Optional.of(HolderSet.direct(items[i].asItem().builtInRegistryHolder())), MinMaxBounds.Ints.ANY, DataComponentMatchers.ANY
				);
			}

			return hasItems(predicates);
		}

		public boolean matches(final Inventory inventory, final ItemStack changedItem, final int slotsFull, final int slotsEmpty, final int slotsOccupied) {
			if (!this.slots.matches(slotsFull, slotsEmpty, slotsOccupied)) {
				return false;
			} else if (this.items.isEmpty()) {
				return true;
			} else if (this.items.size() != 1) {
				List<ItemPredicate> predicates = new ObjectArrayList<>(this.items);
				int count = inventory.getContainerSize();

				for (int slot = 0; slot < count; slot++) {
					if (predicates.isEmpty()) {
						return true;
					}

					ItemStack itemStack = inventory.getItem(slot);
					if (!itemStack.isEmpty()) {
						predicates.removeIf(predicate -> predicate.test((ItemInstance)itemStack));
					}
				}

				return predicates.isEmpty();
			} else {
				return !changedItem.isEmpty() && ((ItemPredicate)this.items.get(0)).test((ItemInstance)changedItem);
			}
		}

		public record Slots(MinMaxBounds.Ints occupied, MinMaxBounds.Ints full, MinMaxBounds.Ints empty) {
			public static final Codec<InventoryChangeTrigger.TriggerInstance.Slots> CODEC = RecordCodecBuilder.create(
				i -> i.group(
						MinMaxBounds.Ints.CODEC.optionalFieldOf("occupied", MinMaxBounds.Ints.ANY).forGetter(InventoryChangeTrigger.TriggerInstance.Slots::occupied),
						MinMaxBounds.Ints.CODEC.optionalFieldOf("full", MinMaxBounds.Ints.ANY).forGetter(InventoryChangeTrigger.TriggerInstance.Slots::full),
						MinMaxBounds.Ints.CODEC.optionalFieldOf("empty", MinMaxBounds.Ints.ANY).forGetter(InventoryChangeTrigger.TriggerInstance.Slots::empty)
					)
					.apply(i, InventoryChangeTrigger.TriggerInstance.Slots::new)
			);
			public static final InventoryChangeTrigger.TriggerInstance.Slots ANY = new InventoryChangeTrigger.TriggerInstance.Slots(
				MinMaxBounds.Ints.ANY, MinMaxBounds.Ints.ANY, MinMaxBounds.Ints.ANY
			);

			public boolean matches(final int slotsFull, final int slotsEmpty, final int slotsOccupied) {
				if (!this.full.matches(slotsFull)) {
					return false;
				} else {
					return !this.empty.matches(slotsEmpty) ? false : this.occupied.matches(slotsOccupied);
				}
			}
		}
	}
}