/*******************************************************************************
    * SAT4J: a SATisfiability library for Java Copyright (C) 2004, 2012 Artois University and CNRS
    *
    * All rights reserved. This program and the accompanying materials
    * are made available under the terms of the Eclipse Public License v1.0
    * which accompanies this distribution, and is available at
    *  http://www.eclipse.org/legal/epl-v10.html
    *
    * Alternatively, the contents of this file may be used under the terms of
   * either the GNU Lesser General Public License Version 2.1 or later (the
   * "LGPL"), in which case the provisions of the LGPL are applicable instead
   * of those above. If you wish to allow use of your version of this file only
   * under the terms of the LGPL, and not to allow others to use your version of
   * this file under the terms of the EPL, indicate your decision by deleting
   * the provisions above and replace them with the notice and other provisions
   * required by the LGPL. If you do not delete the provisions above, a recipient
   * may use your version of this file under the terms of the EPL or the LGPL.
   *
   * Based on the original MiniSat specification from:
   *
   * An extensible SAT solver. Niklas Een and Niklas Sorensson. Proceedings of the
   * Sixth International Conference on Theory and Applications of Satisfiability
   * Testing, LNCS 2919, pp 502-518, 2003.
   *
   * See www.minisat.se for the original solver in C++.
   *
   * Contributors:
   *   CRIL - initial API and implementation
   *******************************************************************************/
  package org.sat4j.tools;
  
  import java.util.ArrayList;
  import java.util.Collection;
  
  import org.sat4j.core.ConstrGroup;
  import org.sat4j.core.VecInt;
  import org.sat4j.specs.ContradictionException;
  import org.sat4j.specs.IConstr;
  import org.sat4j.specs.ISolver;
  import org.sat4j.specs.IVecInt;
  import org.sat4j.specs.IteratorInt;
  import org.sat4j.specs.TimeoutException;
  
  /**
   * Negates the formula inside a solver.
   * 
   * @author leberre
   * 
   * @param <T>
   */
  public class NegationDecorator<T extends ISolver> extends
          AbstractClauseSelectorSolver<T> {
  
      /**
       * 
       */
      private static final long serialVersionUID = 1L;
  
      private final Collection<Integer> addedVars = new ArrayList<Integer>();
  
      public NegationDecorator(T decorated) {
          super(decorated);
          internalState();
      }
  
      @Override
      public IConstr addClause(IVecInt literals) throws ContradictionException {
          int newVar = createNewVar(literals);
          IVecInt clause = new VecInt(2);
          clause.push(newVar);
          ConstrGroup group = new ConstrGroup();
          for (IteratorInt it = literals.iterator(); it.hasNext();) {
              clause.push(-it.next());
              group.add(super.addClause(clause));
              clause.pop();
          }
          addedVars.add(newVar);
          return group;
      }
  
      @Override
      public IConstr addAtMost(IVecInt literals, int degree)
              throws ContradictionException {
          throw new UnsupportedOperationException("Not implemented yet!");
      }
  
      @Override
      public IConstr addAtLeast(IVecInt literals, int degree)
              throws ContradictionException {
          throw new UnsupportedOperationException("Not implemented yet!");
      }
  
      @Override
      public IConstr addExactly(IVecInt literals, int n)
              throws ContradictionException {
          throw new UnsupportedOperationException("Not implemented yet!");
      }
  
      @Override
     public boolean isSatisfiable(IVecInt assumps, boolean global)
             throws TimeoutException {
         IVecInt vars = new VecInt();
         for (int var : getAddedVars()) {
             vars.push(var);
         }
         try {
             IConstr constr = super.addClause(vars);
             boolean returnValue;
             try {
                 returnValue = super.isSatisfiable(assumps, global);
             } finally {
                 removeConstr(constr);
             }
             return returnValue;
         } catch (ContradictionException e) {
             return false;
         }
 
     }
 
     @Override
     public Collection<Integer> getAddedVars() {
         return addedVars;
     }
 
 }