/*******************************************************************************
    * 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 org.sat4j.core.VecInt;
  import org.sat4j.specs.ContradictionException;
  import org.sat4j.specs.IOptimizationProblem;
  import org.sat4j.specs.ISolver;
  import org.sat4j.specs.IVecInt;
  import org.sat4j.specs.TimeoutException;
  
  public class OptToSatAdapter extends SolverDecorator<ISolver> {
  
      /**
       * 
       */
      private static final long serialVersionUID = 1L;
  
      IOptimizationProblem problem;
  
      boolean optimalValueForced = false;
      private final IVecInt assumps = new VecInt();
  
      private long begin;
  
      private final SolutionFoundListener sfl;
  
      public OptToSatAdapter(IOptimizationProblem problem) {
          this(problem, SolutionFoundListener.VOID);
      }
  
      public OptToSatAdapter(IOptimizationProblem problem,
              SolutionFoundListener sfl) {
          super((ISolver) problem);
          this.problem = problem;
          this.sfl = sfl;
      }
  
      @Override
      public void reset() {
          super.reset();
          this.optimalValueForced = false;
      }
  
      @Override
      public boolean isSatisfiable() throws TimeoutException {
          return isSatisfiable(VecInt.EMPTY);
      }
  
      @Override
      public boolean isSatisfiable(boolean global) throws TimeoutException {
          return isSatisfiable();
      }
  
      @Override
      public boolean isSatisfiable(IVecInt myAssumps, boolean global)
              throws TimeoutException {
          return isSatisfiable(myAssumps);
      }
  
      @Override
      public boolean isSatisfiable(IVecInt myAssumps) throws TimeoutException {
          this.assumps.clear();
          myAssumps.copyTo(this.assumps);
          this.begin = System.currentTimeMillis();
          if (this.problem.hasNoObjectiveFunction()) {
              return this.problem.isSatisfiable(myAssumps);
          }
          boolean satisfiable = false;
          try {
              while (this.problem.admitABetterSolution(myAssumps)) {
                  satisfiable = true;
                 sfl.onSolutionFound(this.problem.model());
                 this.problem.discardCurrentSolution();
                 if (isVerbose()) {
                     System.out.println(getLogPrefix()
                             + "Current objective function value: "
                             + this.problem.getObjectiveValue() + "("
                             + (System.currentTimeMillis() - this.begin)
                             / 1000.0 + "s)");
                 }
             }
             sfl.onUnsatTermination();
         } catch (ContradictionException ce) {
             sfl.onUnsatTermination();
         }
         return satisfiable;
     }
 
     @Override
     public int[] model() {
         return this.problem.model();
     }
 
     @Override
     public boolean model(int var) {
         return this.problem.model(var);
     }
 
     @Override
     public int[] modelWithInternalVariables() {
         return decorated().modelWithInternalVariables();
     }
 
     @Override
     public int[] findModel() throws TimeoutException {
         if (isSatisfiable()) {
             return model();
         }
         return null;
     }
 
     @Override
     public int[] findModel(IVecInt assumps) throws TimeoutException {
         if (isSatisfiable(assumps)) {
             return model();
         }
         return null;
     }
 
     @Override
     public String toString(String prefix) {
         return prefix + "Optimization to SAT adapter\n"
                 + super.toString(prefix);
     }
 
     /**
      * Allow to easily check is the solution returned by isSatisfiable is
      * optimal or not.
      * 
      * @return true is the solution found is indeed optimal.
      */
     public boolean isOptimal() {
         return this.problem.isOptimal();
     }
 }