content: /**
   * Copyright (c) 2017-2018, 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.programs.atoms;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  import java.util.Set;
  
  import com.google.common.collect.Sets;
  
  import at.ac.tuwien.kr.alpha.api.grounder.Substitution;
  import at.ac.tuwien.kr.alpha.api.programs.literals.FixedInterpretationLiteral;
  import at.ac.tuwien.kr.alpha.api.programs.terms.ConstantTerm;
  import at.ac.tuwien.kr.alpha.api.programs.terms.IntervalTerm;
  import at.ac.tuwien.kr.alpha.api.programs.terms.Term;
  import at.ac.tuwien.kr.alpha.api.programs.terms.VariableTerm;
  import at.ac.tuwien.kr.alpha.commons.programs.literals.AbstractLiteral;
  import at.ac.tuwien.kr.alpha.commons.programs.terms.Terms;
  import at.ac.tuwien.kr.alpha.commons.substitutions.BasicSubstitution;
  import at.ac.tuwien.kr.alpha.commons.util.Util;
  
  /**
   * @see IntervalAtom
   */
  public class IntervalLiteral extends AbstractLiteral implements FixedInterpretationLiteral {
  
  	public IntervalLiteral(IntervalAtom atom) {
  		super(atom, true);
  	}
  
  	@Override
  	public IntervalAtom getAtom() {
  		return (IntervalAtom) atom;
  	}
  
  	@Override
  	public IntervalLiteral negate() {
  		throw new UnsupportedOperationException("IntervalLiteral cannot be negated");
  	}
  
  	private List<Substitution> getIntervalSubstitutions(Substitution partialSubstitution) {
  		List<Substitution> substitutions = new ArrayList<>();
  		List<Term> terms = getTerms();
  		Term intervalRepresentingVariable = terms.get(1);
  		IntervalTerm intervalTerm = (IntervalTerm) terms.get(0);
  		if (!(intervalTerm.getLowerBound() instanceof ConstantTerm)) {
  			throw Util.oops("Lower bound of interval term " + intervalTerm + " is not a constant!");
  		}
  		@SuppressWarnings("unchecked")
  		int intervalLowerBound = ((ConstantTerm<Integer>) intervalTerm.getLowerBound()).getObject();
  		if (!(intervalTerm.getUpperBound() instanceof ConstantTerm)) {
  			throw Util.oops("Upper bound of interval term " + intervalTerm + " is not a constant!");
  		}
  		@SuppressWarnings("unchecked")
  		int intervalUpperBound = ((ConstantTerm<Integer>) intervalTerm.getUpperBound()).getObject();
  		// Check whether intervalRepresentingVariable is bound already.
  		if (intervalRepresentingVariable instanceof VariableTerm) {
  			// Still a variable, generate all elements in the interval.
  			for (int i = intervalLowerBound; i <= intervalUpperBound; i++) {
  				Substitution ith = new BasicSubstitution(partialSubstitution);
  				ith.put((VariableTerm) intervalRepresentingVariable, Terms.newConstant(i));
  				substitutions.add(ith);
  			}
  			return substitutions;
  		} else {
  			// The intervalRepresentingVariable is bound already, check if it is in the interval.
  			if (!(intervalRepresentingVariable instanceof ConstantTerm)
  					|| !(((ConstantTerm<?>) intervalRepresentingVariable).getObject() instanceof Integer)) {
  				// Term is not bound to an integer constant, not in the interval.
  				return Collections.emptyList();
  			}
  			@SuppressWarnings("unchecked")
  			Integer integer = ((ConstantTerm<Integer>) intervalRepresentingVariable).getObject();
  			if (intervalLowerBound <= integer && integer <= intervalUpperBound) {
  				return Collections.singletonList(partialSubstitution);
  			}
  			return Collections.emptyList();
  		}
  	}
  
  	@Override
  	public Set<VariableTerm> getBindingVariables() {
  		Term term = getTerms().get(1);
  		if (term instanceof VariableTerm) {
  			return Collections.singleton((VariableTerm) term);
  		}
  		return Collections.emptySet();
  	}
  
  	@Override
  	public Set<VariableTerm> getNonBindingVariables() {
  		return Sets.newHashSet(getTerms().get(0).getOccurringVariables());
  	}
  
  	@Override
  	public List<Substitution> getSatisfyingSubstitutions(Substitution partialSubstitution) {
  		// Substitute variables occurring in the interval itself.
  		IntervalLiteral groundInterval = substitute(partialSubstitution);
  		// Generate all substitutions for the interval representing variable.
  		return groundInterval.getIntervalSubstitutions(partialSubstitution);
  	}
  
  	@Override
  	public IntervalLiteral substitute(Substitution substitution) {
  		return new IntervalLiteral(getAtom().substitute(substitution));
  	}
  }
  