package net.minecraft.util;

import com.google.common.collect.HashMultimap;
import com.google.common.collect.ImmutableMultimap;
import com.google.common.collect.Multimap;
import java.util.Optional;
import java.util.function.Supplier;
import java.util.stream.Collectors;
import org.jetbrains.annotations.Nullable;

public interface ProblemReporter {
	ProblemReporter forChild(String name);

	void report(String message);

	public static class Collector implements ProblemReporter {
		private final Multimap<String, String> problems;
		private final Supplier<String> path;
		@Nullable
		private String pathCache;

		public Collector() {
			this(HashMultimap.create(), () -> "");
		}

		private Collector(Multimap<String, String> problems, Supplier<String> path) {
			this.problems = problems;
			this.path = path;
		}

		private String getPath() {
			if (this.pathCache == null) {
				this.pathCache = (String)this.path.get();
			}

			return this.pathCache;
		}

		@Override
		public ProblemReporter forChild(String name) {
			return new ProblemReporter.Collector(this.problems, () -> this.getPath() + name);
		}

		@Override
		public void report(String message) {
			this.problems.put(this.getPath(), message);
		}

		public Multimap<String, String> get() {
			return ImmutableMultimap.copyOf(this.problems);
		}

		public Optional<String> getReport() {
			Multimap<String, String> multimap = this.get();
			if (!multimap.isEmpty()) {
				String string = (String)multimap.asMap()
					.entrySet()
					.stream()
					.map(entry -> " at " + (String)entry.getKey() + ": " + String.join("; ", (Iterable)entry.getValue()))
					.collect(Collectors.joining("\n"));
				return Optional.of(string);
			} else {
				return Optional.empty();
			}
		}
	}
}