content: /**
   * Copyright (c) 2017 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.buildSolverForRegressionTest;
  import static at.ac.tuwien.kr.alpha.core.test.util.TestUtils.runWithTimeout;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Optional;
  
  import org.junit.jupiter.api.Disabled;
  
  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.Programs;
  import at.ac.tuwien.kr.alpha.commons.programs.Programs.ASPCore2ProgramBuilder;
  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;
  
  /**
   * Tests {@link AbstractSolver} using some three-coloring test cases, as described in:
   * Lefèvre, Claire; Béatrix, Christopher; Stéphan, Igor; Garcia, Laurent (2017):
   * ASPeRiX, a first-order forward chaining approach for answer set computing.
   * In Theory and Practice of Logic Programming, pp. 1-45.
   * DOI: 10.1017/S1471068416000569
   */
  public class ThreeColouringWheelTest {
  	
  	private static final long DEBUG_TIMEOUT_FACTOR = 5;
  	
  	@RegressionTest
  	public void testN4(RegressionTestConfig cfg) {
  		long timeout = 1000L;
  		runWithTimeout(cfg, timeout, DEBUG_TIMEOUT_FACTOR, () -> testThreeColouring(4, cfg));
  	}
  
  	@RegressionTest
  	public void testN5(RegressionTestConfig cfg) {
  		long timeout = 1000L;
  		runWithTimeout(cfg, timeout, DEBUG_TIMEOUT_FACTOR, () -> testThreeColouring(5, cfg));
  	}
  
  	@RegressionTest
  	@Disabled("disabled to save resources during CI")
  	public void testN6(RegressionTestConfig cfg) {
  		long timeout = 6000L;
  		runWithTimeout(cfg, timeout, DEBUG_TIMEOUT_FACTOR, () -> testThreeColouring(6, cfg));
  	}
  
  	@RegressionTest
  	@Disabled("disabled to save resources during CI")
  	public void testN3(RegressionTestConfig cfg) {
  		long timeout = 60000L;
  		runWithTimeout(cfg, timeout, DEBUG_TIMEOUT_FACTOR, () -> testThreeColouring(3, cfg));
  	}
  
  	@RegressionTest
  	@Disabled("disabled to save resources during CI")
  	public void testN7(RegressionTestConfig cfg) {
  		long timeout = 60000L;
  		runWithTimeout(cfg, timeout, DEBUG_TIMEOUT_FACTOR, () -> testThreeColouring(7, cfg));
  	}
  
  	@RegressionTest
  	@Disabled("disabled to save resources during CI")
  	public void testN11(RegressionTestConfig cfg) {
  		long timeout = 60000L;
  		runWithTimeout(cfg, timeout, DEBUG_TIMEOUT_FACTOR, () -> testThreeColouring(11, cfg));
  	}
  
  	private void testThreeColouring(int n, RegressionTestConfig cfg) {
  		ASPCore2Program tmpPrg = new ProgramParserImpl().parse(
  				"col(V,C) :- v(V), c(C), not ncol(V,C)." +
  				"ncol(V,C) :- col(V,D), c(C), C != D." +
  				":- e(V,U), col(V,C), col(U,C).");
  		ASPCore2ProgramBuilder prgBuilder = Programs.builder(tmpPrg);
  		prgBuilder.addFacts(createColors("red", "blue", "green"));
  		prgBuilder.addFacts(createVertices(n));
  		prgBuilder.addFacts(createEdges(n));
  		ASPCore2Program program = prgBuilder.build();
  
  		maybeShuffle(program);
  
  		Solver solver = buildSolverForRegressionTest(program, cfg);
  
  		@SuppressWarnings("unused")
  		Optional<AnswerSet> answerSet = solver.stream().findAny();
  		//System.out.println(answerSet);
  
  		// TODO: check correctness of answer set
  	}
  
  	@SuppressWarnings("unused")
  	private void maybeShuffle(ASPCore2Program program) {
  		// FIXME since InputProgram is immutable this needs to be reworked a bit if used
  		// No shuffling here.
  	}
  
  	private List<Atom> createColors(String... colours) {
  		List<Atom> facts = new ArrayList<>(colours.length);
  		Predicate predicate = Predicates.getPredicate("c", 1);
  		for (String colour : colours) {
  			List<Term> terms = new ArrayList<>(1);
  			terms.add(Terms.newConstant(colour));
  			facts.add(Atoms.newBasicAtom(predicate, terms));
  		}
  		return facts;
  	}
  
  	private List<Atom> createVertices(int n) {
  		List<Atom> facts = new ArrayList<>(n);
  		for (int i = 1; i <= n; i++) {
  			facts.add(fact("v", i));
  		}
  		return facts;
  	}
  
  	private List<Atom> createEdges(int n) {
  		List<Atom> facts = new ArrayList<>(n);
  		for (int i = 2; i <= n; i++) {
  			facts.add(fact("e", 1, i));
  		}
  		for (int i = 2; i <= n - 1; i++) {
  			facts.add(fact("e", i, i + 1));
  		}
  		facts.add(fact("e", n, 2));
  		return facts;
  	}
  
  	private Atom fact(String predicateName, int... iTerms) {
  		List<Term> terms = new ArrayList<>(1);
  		Predicate predicate = Predicates.getPredicate(predicateName, iTerms.length);
  		for (int i : iTerms) {
  			terms.add(Terms.newConstant(i));
  		}
  		return Atoms.newBasicAtom(predicate, terms);
  	}
  }
  