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

import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Sets;
import java.util.Optional;
import java.util.Set;
import net.minecraft.core.HolderGetter;
import net.minecraft.resources.ResourceKey;
import net.minecraft.util.ProblemReporter;
import net.minecraft.util.context.ContextKey;
import net.minecraft.util.context.ContextKeySet;

/**
 * Context for validating loot tables. Loot tables are validated recursively by checking that all functions, conditions, etc. (implementing {@link LootContextUser}) are valid according to their LootTable's {@link LootContextParamSet}.
 */
public class ValidationContext {
	private final ProblemReporter reporter;
	private final ContextKeySet contextKeySet;
	private final Optional<HolderGetter.Provider> resolver;
	private final Set<ResourceKey<?>> visitedElements;

	public ValidationContext(ProblemReporter reporter, ContextKeySet contextKeySet, HolderGetter.Provider resolver) {
		this(reporter, contextKeySet, Optional.of(resolver), Set.of());
	}

	public ValidationContext(ProblemReporter reporter, ContextKeySet contextKeySet) {
		this(reporter, contextKeySet, Optional.empty(), Set.of());
	}

	private ValidationContext(ProblemReporter reporter, ContextKeySet contextKeySet, Optional<HolderGetter.Provider> resolver, Set<ResourceKey<?>> visitedElements) {
		this.reporter = reporter;
		this.contextKeySet = contextKeySet;
		this.resolver = resolver;
		this.visitedElements = visitedElements;
	}

	/**
	 * Create a new ValidationContext with {@code childName} being added to the context.
	 */
	public ValidationContext forChild(String childName) {
		return new ValidationContext(this.reporter.forChild(childName), this.contextKeySet, this.resolver, this.visitedElements);
	}

	public ValidationContext enterElement(String name, ResourceKey<?> key) {
		Set<ResourceKey<?>> set = ImmutableSet.<ResourceKey<?>>builder().addAll(this.visitedElements).add(key).build();
		return new ValidationContext(this.reporter.forChild(name), this.contextKeySet, this.resolver, set);
	}

	public boolean hasVisitedElement(ResourceKey<?> key) {
		return this.visitedElements.contains(key);
	}

	/**
	 * Report a problem to this ValidationContext.
	 */
	public void reportProblem(String problem) {
		this.reporter.report(problem);
	}

	public void validateContextUsage(LootContextUser user) {
		Set<ContextKey<?>> set = user.getReferencedContextParams();
		Set<ContextKey<?>> set2 = Sets.<ContextKey<?>>difference(set, this.contextKeySet.allowed());
		if (!set2.isEmpty()) {
			this.reporter.report("Parameters " + set2 + " are not provided in this context");
		}
	}

	public HolderGetter.Provider resolver() {
		return (HolderGetter.Provider)this.resolver.orElseThrow(() -> new UnsupportedOperationException("References not allowed"));
	}

	public boolean allowsReferences() {
		return this.resolver.isPresent();
	}

	public ValidationContext setContextKeySet(ContextKeySet contextKeySet) {
		return new ValidationContext(this.reporter, contextKeySet, this.resolver, this.visitedElements);
	}

	public ProblemReporter reporter() {
		return this.reporter;
	}
}