content: /**
   * Copyright (c) 2017-2019 Siemens AG
   * All rights reserved.
   * 
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   * 
   * 1) Redistributions of source code must retain the above copyright notice, this
   *    list of conditions and the following disclaimer.
   * 
   * 2) Redistributions in binary form must reproduce the above copyright notice,
   *    this list of conditions and the following disclaimer in the documentation
   *    and/or other materials provided with the distribution.
   * 
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  package at.ac.tuwien.kr.alpha.core.solver;
  
  import static at.ac.tuwien.kr.alpha.core.test.util.TestUtils.runWithTimeout;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  import java.io.IOException;
  import java.nio.file.Paths;
  import java.util.Optional;
  import java.util.SortedSet;
  
  import org.junit.jupiter.api.Disabled;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import at.ac.tuwien.kr.alpha.api.AnswerSet;
  import at.ac.tuwien.kr.alpha.api.Solver;
  import at.ac.tuwien.kr.alpha.api.programs.ASPCore2Program;
  import at.ac.tuwien.kr.alpha.api.programs.Predicate;
  import at.ac.tuwien.kr.alpha.api.programs.atoms.Atom;
  import at.ac.tuwien.kr.alpha.api.programs.terms.Term;
  import at.ac.tuwien.kr.alpha.commons.Predicates;
  import at.ac.tuwien.kr.alpha.commons.programs.atoms.Atoms;
  import at.ac.tuwien.kr.alpha.commons.programs.terms.Terms;
  import at.ac.tuwien.kr.alpha.core.parser.ProgramParserImpl;
  import at.ac.tuwien.kr.alpha.core.test.util.TestUtils;
  
  /**
   * Tests {@link AbstractSolver} using some hanoi tower test cases (see https://en.wikipedia.org/wiki/Tower_of_Hanoi).
   *
   */
  public class HanoiTowerTest {
  
  	@SuppressWarnings("unused")
  	private static final Logger LOGGER = LoggerFactory.getLogger(HanoiTowerTest.class);
  
  	private static final int DEBUG_TIMEOUT_FACTOR = 5;
  
  	@RegressionTest
  	@Disabled("disabled to save resources during CI")
  	public void testInstance1(RegressionTestConfig cfg) {
  		long timeout = 10000L;
  		runWithTimeout(cfg, timeout, DEBUG_TIMEOUT_FACTOR, () -> testHanoiTower(1, cfg));
  	}
  
  	@RegressionTest
  	@Disabled("disabled to save resources during CI")
  	public void testInstance2(RegressionTestConfig cfg) {
  		long timeout = 10000L;
  		runWithTimeout(cfg, timeout, DEBUG_TIMEOUT_FACTOR, () -> testHanoiTower(2, cfg));
  	}
  
  	@RegressionTest
  	@Disabled("disabled to save resources during CI")
  	public void testInstance3(RegressionTestConfig cfg) {
  		long timeout = 10000L;
  		runWithTimeout(cfg, timeout, DEBUG_TIMEOUT_FACTOR, () -> testHanoiTower(3, cfg));
  	}
  
  	@RegressionTest
  	@Disabled("disabled to save resources during CI")
  	public void testInstance4(RegressionTestConfig cfg) {
  		long timeout = 10000L;
  		runWithTimeout(cfg, timeout, DEBUG_TIMEOUT_FACTOR, () -> testHanoiTower(4, cfg));
  	}
  
  	@RegressionTest
  	public void testSimple(RegressionTestConfig cfg) {
  		TestUtils.ignoreTestForNaiveSolver(cfg);
  		TestUtils.ignoreTestForNonDefaultDomainIndependentHeuristics(cfg);
  		long timeout = 60000L;
  		runWithTimeout(cfg, timeout, DEBUG_TIMEOUT_FACTOR, () -> testHanoiTower("simple", cfg));
  	}
  
  	private void testHanoiTower(int instance, RegressionTestConfig cfg) throws IOException {
  		testHanoiTower(String.valueOf(instance), cfg);
  	}
  
  	private void testHanoiTower(String instance, RegressionTestConfig cfg) throws IOException {
  		ASPCore2Program prog = new ProgramParserImpl().parse(
  				Paths.get("src", "test", "resources", "HanoiTower_Alpha.asp"),
  				Paths.get("src", "test", "resources", "HanoiTower_instances", instance + ".asp"));
  		Solver solver = TestUtils.buildSolverForRegressionTest(prog, cfg);
  		Optional<AnswerSet> answerSet = solver.stream().findFirst();
  		assertTrue(answerSet.isPresent());
  		checkGoal(prog, answerSet.get());
  	}
  
  	/**
  	 * Conducts a very simple, non-comprehensive goal check (i.e. it may classify answer sets as correct that are actually wrong) by checking if
  	 * for every goal/3
  	 * fact in the input there is a corresponding on/3 atom in the output.
  	 */
  	private void checkGoal(ASPCore2Program parsedProgram, AnswerSet answerSet) {
  		Predicate ongoal = Predicates.getPredicate("ongoal", 2);
  		Predicate on = Predicates.getPredicate("on", 3);
  		int steps = getSteps(parsedProgram);
  		SortedSet<Atom> onInstancesInAnswerSet = answerSet.getPredicateInstances(on);
  		for (Atom atom : parsedProgram.getFacts()) {
  			if (atom.getPredicate().getName().equals(ongoal.getName()) && atom.getPredicate().getArity() == ongoal.getArity()) {
  				Term expectedTop = atom.getTerms().get(0);
  				Term expectedBottom = atom.getTerms().get(1);
  				Term expectedSteps = Terms.newConstant(steps);
  				Atom expectedAtom = Atoms.newBasicAtom(on, expectedSteps, expectedBottom, expectedTop);
  				assertTrue(onInstancesInAnswerSet.contains(expectedAtom), "Answer set does not contain " + expectedAtom);
  			}
  		}
  	}
  
  	private int getSteps(ASPCore2Program parsedProgram) {
  		Predicate steps = Predicates.getPredicate("steps", 1);
  		for (Atom atom : parsedProgram.getFacts()) {
  			if (atom.getPredicate().getName().equals(steps.getName()) && atom.getPredicate().getArity() == steps.getArity()) {
  				return Integer.valueOf(atom.getTerms().get(0).toString());
  			}
  		}
  		throw new IllegalArgumentException("No steps atom found in input program.");
  	}
  
  }
  