package net.minecraft.util;

import com.google.common.collect.ImmutableSet;
import java.util.Map;
import java.util.Set;
import java.util.function.Consumer;

public final class Graph {
	private Graph() {
	}

	public static <T> boolean depthFirstSearch(
		final Map<T, Set<T>> edges, final Set<T> discovered, final Set<T> currentlyVisiting, final Consumer<T> reverseTopologicalOrder, final T current
	) {
		if (discovered.contains(current)) {
			return false;
		} else if (currentlyVisiting.contains(current)) {
			return true;
		} else {
			currentlyVisiting.add(current);

			for (T next : (Set)edges.getOrDefault(current, ImmutableSet.of())) {
				if (depthFirstSearch(edges, discovered, currentlyVisiting, reverseTopologicalOrder, next)) {
					return true;
				}
			}

			currentlyVisiting.remove(current);
			discovered.add(current);
			reverseTopologicalOrder.accept(current);
			return false;
		}
	}
}