/*******************************************************************************
    * 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.pb.tools;
  
  import java.math.BigInteger;
  import java.util.Iterator;
  
  import org.sat4j.core.Vec;
  import org.sat4j.core.VecInt;
  import org.sat4j.pb.IPBSolver;
  import org.sat4j.pb.ObjectiveFunction;
  import org.sat4j.specs.ContradictionException;
  import org.sat4j.specs.IVec;
  import org.sat4j.specs.IVecInt;
  import org.sat4j.specs.TimeoutException;
  
  public class SteppedTimeoutLexicoDecoratorPB extends LexicoDecoratorPB {
  
      /**
  	 * 
  	 */
      private static final long serialVersionUID = 1L;
  
      public SteppedTimeoutLexicoDecoratorPB(IPBSolver solver) {
          super(solver);
      }
  
      @Override
      public boolean admitABetterSolution(IVecInt assumps)
              throws TimeoutException {
          decorated().setObjectiveFunction(this.objs.get(this.currentCriterion));
          this.isSolutionOptimal = false;
          try {
              if (decorated().isSatisfiable(assumps, true)) {
                  this.prevboolmodel = new boolean[nVars()];
                  for (int i = 0; i < nVars(); i++) {
                      this.prevboolmodel[i] = decorated().model(i + 1);
                  }
                  this.prevfullmodel = decorated().model();
                  this.prevmodelwithinternalvars = decorated()
                          .modelWithInternalVariables();
                  calculateObjective();
                  return true;
              }
              decorated().expireTimeout();
              return manageUnsatCase();
          } catch (TimeoutException te) {
              if (this.currentCriterion == numberOfCriteria() - 1) {
                  throw te;
              }
              mergeCurrentandNextCriteria();
              if (this.prevConstr != null) {
                  super.removeConstr(this.prevConstr);
                  this.prevConstr = null;
              }
              try {
                  fixCriterionValue();
              } catch (ContradictionException ce) {
                  throw new IllegalStateException(ce);
              }
              if (isVerbose()) {
                  System.out.println(getLogPrefix()
                          + "Partial timeout criterion number "
                          + (this.currentCriterion + 1));
              }
              this.currentCriterion++;
              calculateObjective();
              decorated().expireTimeout();
              return true;
          }
      }
  
     private void mergeCurrentandNextCriteria() {
         ObjectiveFunction currentObj = this.objs.get(this.currentCriterion);
         int currentObjSize = currentObj.getVars().size();
         ObjectiveFunction nextObj = this.objs.get(this.currentCriterion + 1);
         int nextObjSize = nextObj.getVars().size();
         IVecInt newLits = new VecInt(currentObjSize + nextObjSize);
         currentObj.getVars().copyTo(newLits);
         nextObj.getVars().copyTo(newLits);
         IVec<BigInteger> newCoeffs = new Vec<BigInteger>(currentObjSize
                 + nextObjSize);
         BigInteger coeffFactor = BigInteger.valueOf(nextObjSize).add(
                 BigInteger.ONE);
         for (Iterator<BigInteger> it = currentObj.getCoeffs().iterator(); it
                 .hasNext();) {
             newCoeffs.push(it.next().multiply(coeffFactor));
         }
         nextObj.getCoeffs().copyTo(newCoeffs);
         this.objs.set(this.currentCriterion + 1, new ObjectiveFunction(newLits,
                 newCoeffs));
     }
 
 }