package edu.rice.comp322;

import edu.rice.hj.api.HjFuture;

import static edu.rice.hj.Module0.launchHabaneroApp;
import static edu.rice.hj.Module1.future;

/**
 * Solution to Worksheet 5.
 *
 * @author Shams Imam
 */
public final class Worksheet5 {

    /**
     * Disallow instance creation of utility class.
     */
    private Worksheet5() {
        super();
    }

    /**
     * The main method.
     *
     * @param args an array of {@link String} objects.
     */
    public static void main(final String[] args) {

        launchHabaneroApp(() -> {

            final HjFuture<Void> A =
                future(() -> {
                    return process("A");
                });
            final HjFuture<Void> B =
                future(() -> {
                    A.get();
                    return process("B");
                });
            final HjFuture<Void> C =
                future(() -> {
                    A.get();
                    return process("C");
                });
            final HjFuture<Void> D =
                future(() -> {
                    B.get();
                    C.get();
                    return process("D");
                });
            final HjFuture<Void> E =
                future(() -> {
                    C.get();
                    return process("E");
                });
            final HjFuture<Void> F =
                future(() -> {
                    D.get();
                    E.get();
                    return process("F");
                });
            F.get();

        });

    }

    private static Void process(String a) {
        try {
            // random sleep to influence scheduling outputs
            Thread.sleep((long)(Math.random() * 2_000));
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println(a);
        return null;
    }
}