content: /*
   * Copyright (c) 2017-2020, the Alpha Team.
   * All rights reserved.
   * 
   * Additional changes made by Siemens.
   * 
   * 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.grounder;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  import static org.junit.jupiter.api.Assertions.fail;
  
  import java.util.function.Function;
  
  import org.junit.jupiter.api.Test;
  
  import at.ac.tuwien.kr.alpha.api.config.SystemConfig;
  import at.ac.tuwien.kr.alpha.api.programs.ProgramParser;
  import at.ac.tuwien.kr.alpha.api.programs.literals.Literal;
  import at.ac.tuwien.kr.alpha.core.parser.ProgramParserImpl;
  import at.ac.tuwien.kr.alpha.core.parser.ProgramPartParser;
  import at.ac.tuwien.kr.alpha.core.programs.CompiledProgram;
  import at.ac.tuwien.kr.alpha.core.programs.InternalProgram;
  import at.ac.tuwien.kr.alpha.core.programs.rules.CompiledRule;
  import at.ac.tuwien.kr.alpha.core.programs.transformation.NormalizeProgramTransformation;
  
  /**
   * Copyright (c) 2017-2019, the Alpha Team.
   */
  public class RuleGroundingOrderTest {
  
  	private static final ProgramParser PARSER = new ProgramParserImpl();
  	private static final NormalizeProgramTransformation NORMALIZE_TRANSFORM = new NormalizeProgramTransformation(
  			SystemConfig.DEFAULT_AGGREGATE_REWRITING_CONFIG);
  	private static final Function<String, CompiledProgram> PARSE_AND_PREPROCESS = (str) -> {
  		return InternalProgram.fromNormalProgram(NORMALIZE_TRANSFORM.apply(PARSER.parse(str)));
  	};
  
  	private static final ProgramPartParser PROGRAM_PART_PARSER = new ProgramPartParser();
  
  	@Test
  	public void groundingOrder() {
  		String aspStr = "h(X,C) :- p(X,Y), q(A,B), r(Y,A), s(C)." +
  				"j(A,B,X,Y) :- r1(A,B), r1(X,Y), r1(A,X), r1(B,Y), A = B." +
  				"p(a) :- b = a.";
  		CompiledProgram prog = PARSE_AND_PREPROCESS.apply(aspStr);
  		CompiledRule rule0 = prog.getRules().get(0);
  		RuleGroundingInfo rgo0 = new RuleGroundingInfoImpl(rule0);
  		rgo0.computeGroundingOrders();
  		assertEquals(4, rgo0.getStartingLiterals().size());
  
  		CompiledRule rule1 = prog.getRules().get(1);
  		RuleGroundingInfo rgo1 = new RuleGroundingInfoImpl(rule1);
  		rgo1.computeGroundingOrders();
  		assertEquals(4, rgo1.getStartingLiterals().size());
  
  		CompiledRule rule2 = prog.getRules().get(2);
  		RuleGroundingInfo rgo2 = new RuleGroundingInfoImpl(rule2);
  		rgo2.computeGroundingOrders();
  		assertTrue(rgo2.hasFixedInstantiation());
  	}
  
  	@Test
  	public void groundingOrderUnsafe() {
  		assertThrows(RuntimeException.class, () -> {
  			String aspStr = "h(X,C) :- X = Y, Y = C .. 3, C = X.";
  			CompiledProgram prog = PARSE_AND_PREPROCESS.apply(aspStr);
  			computeGroundingOrdersForRule(prog, 0);
  		});
  	}
  
  	@Test
  	public void testPositionFromWhichAllVarsAreBound_ground() {
  		String aspStr = "a :- b, not c.";
  		CompiledProgram internalPrg = PARSE_AND_PREPROCESS.apply(aspStr);
  		RuleGroundingInfo rgo0 = computeGroundingOrdersForRule(internalPrg, 0);
  		assertEquals(0, rgo0.getFixedGroundingOrder().getPositionFromWhichAllVarsAreBound());
  	}
  
  	@Test
  	public void testPositionFromWhichAllVarsAreBound_simpleNonGround() {
  		String aspStr = "a(X) :- b(X), not c(X).";
  		CompiledProgram internalPrg = PARSE_AND_PREPROCESS.apply(aspStr);
  		RuleGroundingInfo rgo0 = computeGroundingOrdersForRule(internalPrg, 0);
  		assertEquals(1, rgo0.getStartingLiterals().size());
  		for (Literal startingLiteral : rgo0.getStartingLiterals()) {
  			assertEquals(0, rgo0.orderStartingFrom(startingLiteral).getPositionFromWhichAllVarsAreBound());
  		}
  	}
  
  	@Test
  	public void testPositionFromWhichAllVarsAreBound_longerSimpleNonGround() {
  		String aspStr = "a(X) :- b(X), c(X), d(X), not e(X).";
  		CompiledProgram internalPrg = PARSE_AND_PREPROCESS.apply(aspStr);
  		RuleGroundingInfo rgo0 = computeGroundingOrdersForRule(internalPrg, 0);
  		assertEquals(3, rgo0.getStartingLiterals().size());
  		for (Literal startingLiteral : rgo0.getStartingLiterals()) {
  			assertEquals(0, rgo0.orderStartingFrom(startingLiteral).getPositionFromWhichAllVarsAreBound());
  		}
  	}
  
  	@Test
  	public void testToString_longerSimpleNonGround() {
  		String aspStr = "a(X) :- b(X), c(X), d(X), not e(X).";
  		CompiledProgram internalPrg = PARSE_AND_PREPROCESS.apply(aspStr);
  		RuleGroundingInfo rgo0 = computeGroundingOrdersForRule(internalPrg, 0);
  		assertEquals(3, rgo0.getStartingLiterals().size());
  		for (Literal startingLiteral : rgo0.getStartingLiterals()) {
  			switch (startingLiteral.getPredicate().getName()) {
  				case "b":
  					assertEquals("b(X) : | c(X), d(X), not e(X)", rgo0.orderStartingFrom(startingLiteral).toString());
  					break;
  				case "c":
  					assertEquals("c(X) : | b(X), d(X), not e(X)", rgo0.orderStartingFrom(startingLiteral).toString());
  					break;
  				case "d":
  					assertEquals("d(X) : | b(X), c(X), not e(X)", rgo0.orderStartingFrom(startingLiteral).toString());
  					break;
  				default:
  					fail("Unexpected starting literal: " + startingLiteral);
  			}
  		}
  	}
  
  	@Test
  	public void testPositionFromWhichAllVarsAreBound_joinedNonGround() {
  		String aspStr = "a(X) :- b(X), c(X,Y), d(X,Z), not e(X).";
  		CompiledProgram internalPrg = PARSE_AND_PREPROCESS.apply(aspStr);
  		RuleGroundingInfo rgo0 = computeGroundingOrdersForRule(internalPrg, 0);
  		final Literal litBX = PROGRAM_PART_PARSER.parseLiteral("b(X)");
  		final Literal litCXY = PROGRAM_PART_PARSER.parseLiteral("c(X,Y)");
  		final Literal litDXZ = PROGRAM_PART_PARSER.parseLiteral("d(X,Z)");
  		assertTrue(2 <= rgo0.orderStartingFrom(litBX).getPositionFromWhichAllVarsAreBound());
  		assertTrue(1 <= rgo0.orderStartingFrom(litCXY).getPositionFromWhichAllVarsAreBound());
  		assertTrue(1 <= rgo0.orderStartingFrom(litDXZ).getPositionFromWhichAllVarsAreBound());
  	}
  
  	private RuleGroundingInfo computeGroundingOrdersForRule(CompiledProgram program, int ruleIndex) {
  		CompiledRule rule = program.getRules().get(ruleIndex);
  		RuleGroundingInfo rgo = new RuleGroundingInfoImpl(rule);
  		rgo.computeGroundingOrders();
  		return rgo;
  	}
  
  }
  