package net.minecraft.world.level.storage.loot.entries;

import com.mojang.serialization.MapCodec;
import com.mojang.serialization.codecs.RecordCodecBuilder;
import java.util.List;
import java.util.function.Consumer;
import net.minecraft.util.ProblemReporter;
import net.minecraft.world.level.storage.loot.LootContext;
import net.minecraft.world.level.storage.loot.Validatable;
import net.minecraft.world.level.storage.loot.ValidationContext;
import net.minecraft.world.level.storage.loot.predicates.LootItemCondition;

public abstract class CompositeEntryBase extends LootPoolEntryContainer {
	public static final ProblemReporter.Problem NO_CHILDREN_PROBLEM = new ProblemReporter.Problem() {
		@Override
		public String description() {
			return "Empty children list";
		}
	};
	protected final List<LootPoolEntryContainer> children;
	private final ComposableEntryContainer composedChildren;

	protected CompositeEntryBase(final List<LootPoolEntryContainer> children, final List<LootItemCondition> conditions) {
		super(conditions);
		this.children = children;
		this.composedChildren = this.compose(children);
	}

	@Override
	public abstract MapCodec<? extends CompositeEntryBase> codec();

	@Override
	public void validate(final ValidationContext context) {
		super.validate(context);
		if (this.children.isEmpty()) {
			context.reportProblem(NO_CHILDREN_PROBLEM);
		}

		Validatable.validate(context, "children", this.children);
	}

	protected abstract ComposableEntryContainer compose(List<? extends ComposableEntryContainer> entries);

	@Override
	public final boolean expand(final LootContext context, final Consumer<LootPoolEntry> output) {
		return !this.canRun(context) ? false : this.composedChildren.expand(context, output);
	}

	public static <T extends CompositeEntryBase> MapCodec<T> createCodec(final CompositeEntryBase.CompositeEntryConstructor<T> constructor) {
		return RecordCodecBuilder.mapCodec(
			i -> i.group(LootPoolEntries.CODEC.listOf().optionalFieldOf("children", List.of()).forGetter(e -> e.children))
				.and(commonFields(i).t1())
				.apply(i, constructor::create)
		);
	}

	@FunctionalInterface
	public interface CompositeEntryConstructor<T extends CompositeEntryBase> {
		T create(List<LootPoolEntryContainer> children, List<LootItemCondition> conditions);
	}
}