content: /**
   * Copyright (c) 2018 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.programs.atoms;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Set;
  import java.util.stream.Collectors;
  
  import org.junit.jupiter.api.Disabled;
  import org.junit.jupiter.api.Test;
  
  import at.ac.tuwien.kr.alpha.api.common.fixedinterpretations.PredicateInterpretation;
  import at.ac.tuwien.kr.alpha.api.programs.ProgramParser;
  import at.ac.tuwien.kr.alpha.api.programs.atoms.Atom;
  import at.ac.tuwien.kr.alpha.api.programs.literals.Literal;
  import at.ac.tuwien.kr.alpha.api.programs.rules.Rule;
  import at.ac.tuwien.kr.alpha.api.programs.rules.heads.Head;
  import at.ac.tuwien.kr.alpha.api.programs.terms.VariableTerm;
  import at.ac.tuwien.kr.alpha.commons.comparisons.ComparisonOperators;
  import at.ac.tuwien.kr.alpha.core.common.fixedinterpretations.IntPredicateInterpretation;
  import at.ac.tuwien.kr.alpha.core.parser.ProgramParserImpl;
  
  /**
   * Tests the behaviour of {@link Literal#getBindingVariables()} and {@link Literal#getNonBindingVariables()}
   * on classes implementing {@link Atom}.
   *
   */
  public class LiteralBindingNonBindingVariablesTest {
  
  	private final Map<String, PredicateInterpretation> externals = new HashMap<>();
  	private final ProgramParser parser = new ProgramParserImpl();
  
  	@Test
  	public void testPositiveBasicLiteral() {
  		Literal literal = parser.parse("p(X,Y) :- q(X,Y).").getRules().get(0).getBody().stream().findFirst().get();
  		assertEquals(false, literal.isNegated());
  		expectVariables(literal.getBindingVariables(), "X", "Y");
  		expectVariables(literal.getNonBindingVariables());
  	}
  
  	@Test
  	public void testNegativeBasicLiteral() {
  		Literal literal = parser.parse("p(X,Y) :- q(X,Y), not r(X,Y).").getRules().get(0).getNegativeBody().stream().findFirst().get();
  		assertEquals(true, literal.isNegated());
  		expectVariables(literal.getBindingVariables());
  		expectVariables(literal.getNonBindingVariables(), "X", "Y");
  	}
  
  	@Test
  	public void testPositiveComparisonLiteral_EQ_LeftAssigning() {
  		Rule<Head> rule = parser.parse("p(X) :- q(X,Y), Y = 5.").getRules().get(0);
  		Literal literal = rule.getBody().stream().filter((lit) -> lit.getPredicate() == ComparisonOperators.EQ.toPredicate()).findFirst().get();
  		assertEquals(false, literal.isNegated());
  		expectVariables(literal.getBindingVariables(), "Y");
  		expectVariables(literal.getNonBindingVariables());
  	}
  
  	@Test
  	public void testNegativeComparisonLiteral_EQ_LeftAssigning() {
  		Rule<Head> rule = parser.parse("p(X) :- q(X,Y), not Y = 5.").getRules().get(0);
  		Literal literal = rule.getNegativeBody().stream().findFirst().get();
  		assertEquals(true, literal.isNegated());
  		expectVariables(literal.getBindingVariables());
  		expectVariables(literal.getNonBindingVariables(), "Y");
  	}
  
  	@Test
  	public void testPositiveComparisonLiteral_EQ_RightAssigning() {
  		Rule<Head> rule = parser.parse("p(X) :- q(X,Y), 5 = Y.").getRules().get(0);
  		Literal literal = rule.getBody().stream().filter((lit) -> lit.getPredicate() == ComparisonOperators.EQ.toPredicate()).findFirst().get();
  		assertEquals(false, literal.isNegated());
  		expectVariables(literal.getBindingVariables(), "Y");
  		expectVariables(literal.getNonBindingVariables());
  	}
  
  	@Test
  	public void testNegativeComparisonLiteral_EQ_RightAssigning() {
  		Literal literal = parser.parse("p(X) :- q(X,Y), not 5 = Y.").getRules().get(0).getNegativeBody().stream().findFirst().get();
  		assertEquals(true, literal.isNegated());
  		expectVariables(literal.getBindingVariables());
  		expectVariables(literal.getNonBindingVariables(), "Y");
  	}
  
  	@Test
  	@Disabled("Literals of this kind are compiled away by VariableEqualityRemoval")
  	public void testPositiveComparisonLiteral_EQ_Bidirectional() {
  		Rule<Head> rule = parser.parse("p(X) :- q(X,Y), X = Y.").getRules().get(0);
  		Literal literal = rule.getBody().stream().filter((lit) -> lit.getPredicate() == ComparisonOperators.EQ.toPredicate()).findFirst().get();
  		assertEquals(false, literal.isNegated());
  		expectVariables(literal.getBindingVariables());
  		expectVariables(literal.getNonBindingVariables(), "X", "Y");
  	}
  
  	@Test
  	public void testNegativeComparisonLiteral_EQ_Bidirectional() {
  		Literal literal = parser.parse("p(X) :- q(X,Y), not X = Y.").getRules().get(0).getNegativeBody().stream().findFirst().get();
  		assertEquals(true, literal.isNegated());
  		expectVariables(literal.getBindingVariables());
  		expectVariables(literal.getNonBindingVariables(), "X", "Y");
  	}
  
  	@Test
  	public void testPositiveComparisonLiteral_NEQ_LeftAssigning() {
  		Rule<Head> rule = parser.parse("p(X) :- q(X,Y), Y != 5.").getRules().get(0);
  		Literal literal = rule.getBody().stream().filter((lit) -> lit.getPredicate() == ComparisonOperators.NE.toPredicate()).findFirst().get();
  		assertEquals(false, literal.isNegated());
  		expectVariables(literal.getBindingVariables());
  		expectVariables(literal.getNonBindingVariables(), "Y");
  	}
  
  	@Test
  	public void testNegativeComparisonLiteral_NEQ_LeftAssigning() {
  		Literal literal = parser.parse("p(X) :- q(X,Y), not Y != 5.").getRules().get(0).getNegativeBody().stream().findFirst().get();
  		assertEquals(true, literal.isNegated());
  		expectVariables(literal.getBindingVariables(), "Y");
  		expectVariables(literal.getNonBindingVariables());
  	}
  
  	@Test
  	public void testPositiveComparisonLiteral_NEQ_RightAssigning() {
  		Rule<Head> rule = parser.parse("p(X) :- q(X,Y), 5 != Y.").getRules().get(0);
  		Literal literal = rule.getBody().stream().filter((lit) -> lit.getPredicate() == ComparisonOperators.NE.toPredicate()).findFirst().get();
  		assertEquals(false, literal.isNegated());
  		expectVariables(literal.getBindingVariables());
  		expectVariables(literal.getNonBindingVariables(), "Y");
  	}
  
  	@Test
  	public void testNegativeComparisonLiteral_NEQ_RightAssigning() {
  		Literal literal = parser.parse("p(X) :- q(X,Y), not 5 != Y.").getRules().get(0).getNegativeBody().stream().findFirst().get();
  		assertEquals(true, literal.isNegated());
  		expectVariables(literal.getBindingVariables(), "Y");
  		expectVariables(literal.getNonBindingVariables());
  	}
  
  	@Test
  	public void testPositiveComparisonLiteral_NEQ_Bidirectional() {
  		Rule<Head> rule = parser.parse("p(X) :- q(X,Y), X != Y.").getRules().get(0);
  		Literal literal = rule.getBody().stream().filter((lit) -> lit.getPredicate() == ComparisonOperators.NE.toPredicate()).findFirst().get();
  		assertEquals(false, literal.isNegated());
  		expectVariables(literal.getBindingVariables());
  		expectVariables(literal.getNonBindingVariables(), "X", "Y");
  	}
  
  	@Test
  	@Disabled("Literals of this kind are compiled away by VariableEqualityRemoval")
  	public void testNegativeComparisonLiteral_NEQ_Bidirectional() {
  		Literal literal = parser.parse("p(X) :- q(X,Y), not X != Y.").getRules().get(0).getNegativeBody().stream().findFirst().get();
  		assertEquals(true, literal.isNegated());
  		expectVariables(literal.getBindingVariables(), "X", "Y");
  		expectVariables(literal.getNonBindingVariables());
  	}
  
  	@Test
  	public void testPositiveExternalLiteral() {
  		externals.put("ext", new IntPredicateInterpretation(i -> i > 0));
  		Rule<Head> rule = parser.parse("p(X) :- q(Y), &ext[Y](X).", externals).getRules().get(0);
  		Literal literal = rule.getBody().stream().filter((lit) -> lit.getPredicate().getName().equals("ext")).findFirst().get();
  		assertEquals(false, literal.isNegated());
  		expectVariables(literal.getBindingVariables(), "X");
  		expectVariables(literal.getNonBindingVariables(), "Y");
  	}
  
  	@Test
  	public void testNegativeExternalLiteral() {
  		externals.put("ext", new IntPredicateInterpretation(i -> i > 0));
  		Literal literal = parser.parse("p(X) :- q(Y), not &ext[Y](X).", externals).getRules().get(0).getNegativeBody().stream().findFirst().get();
  		assertEquals(true, literal.isNegated());
  		expectVariables(literal.getBindingVariables());
  		expectVariables(literal.getNonBindingVariables(), "X", "Y");
  	}
  
  	private void expectVariables(Collection<VariableTerm> variables, String... expectedVariableNames) {
  		Set<String> setActualVariableNames = variables.stream().map(VariableTerm::toString).collect(Collectors.toSet());
  		Set<String> setExpectedVariableNames = Arrays.stream(expectedVariableNames).collect(Collectors.toSet());
  		assertEquals(setExpectedVariableNames, setActualVariableNames);
  	}
  
  }
  