/*******************************************************************************
    * 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.core;
  
  import java.io.PrintStream;
  import java.io.PrintWriter;
  import java.math.BigInteger;
  import java.util.ArrayList;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  
  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.IConstr;
  import org.sat4j.specs.ISolver;
  import org.sat4j.specs.ISolverService;
  import org.sat4j.specs.IVec;
  import org.sat4j.specs.IVecInt;
  import org.sat4j.specs.IteratorInt;
  import org.sat4j.specs.SearchListener;
  import org.sat4j.specs.TimeoutException;
  
  public class ObjectiveReducerPBSolverDecorator implements IPBSolver {
  
      private static final long serialVersionUID = -1637773414229087105L;
  
      private final IPBSolver decorated;
  
      private final List<IVecInt> atMostOneCstrs = new ArrayList<IVecInt>();
  
      public ObjectiveReducerPBSolverDecorator(IPBSolver decorated) {
          this.decorated = decorated;
      }
  
      public int[] model() {
          return decorated.model();
      }
  
      @SuppressWarnings("deprecation")
      public int newVar() {
          return decorated.newVar();
      }
  
      public IConstr addPseudoBoolean(IVecInt lits, IVec<BigInteger> coeffs,
              boolean moreThan, BigInteger d) throws ContradictionException {
          return decorated.addPseudoBoolean(lits, coeffs, moreThan, d);
      }
  
      public boolean model(int var) {
          return decorated.model(var);
      }
  
      public int nextFreeVarId(boolean reserve) {
          return decorated.nextFreeVarId(reserve);
      }
  
      public int[] primeImplicant() {
          return decorated.primeImplicant();
      }
  
      public boolean primeImplicant(int p) {
          return decorated.primeImplicant(p);
      }
  
      public IConstr addAtMost(IVecInt literals, IVecInt coeffs, int degree)
              throws ContradictionException {
         for (IteratorInt it = coeffs.iterator(); it.hasNext();) {
             if (it.next() != degree) {
                 return decorated.addAtMost(literals, coeffs, degree);
             }
         }
         this.atMostOneCstrs.add(literals);
         return decorated.addAtMost(literals, coeffs, degree);
     }
 
     public boolean isSatisfiable() throws TimeoutException {
         return decorated.isSatisfiable();
     }
 
     public boolean isSatisfiable(IVecInt assumps, boolean globalTimeout)
             throws TimeoutException {
         return decorated.isSatisfiable(assumps, globalTimeout);
     }
 
     public void registerLiteral(int p) {
         decorated.registerLiteral(p);
     }
 
     public void setExpectedNumberOfClauses(int nb) {
         decorated.setExpectedNumberOfClauses(nb);
     }
 
     public IConstr addAtMost(IVecInt literals, IVec<BigInteger> coeffs,
             BigInteger degree) throws ContradictionException {
         for (Iterator<BigInteger> it = coeffs.iterator(); it.hasNext();) {
             if (!it.next().equals(degree)) {
                 return decorated.addAtMost(literals, coeffs, degree);
             }
         }
         this.atMostOneCstrs.add(literals);
         return decorated.addAtMost(literals, coeffs, degree);
     }
 
     public boolean isSatisfiable(boolean globalTimeout) throws TimeoutException {
         return decorated.isSatisfiable(globalTimeout);
     }
 
     public IConstr addClause(IVecInt literals) throws ContradictionException {
         return decorated.addClause(literals);
     }
 
     public boolean isSatisfiable(IVecInt assumps) throws TimeoutException {
         return decorated.isSatisfiable(assumps);
     }
 
     public IConstr addAtLeast(IVecInt literals, IVecInt coeffs, int degree)
             throws ContradictionException {
         return decorated.addAtLeast(literals, coeffs, degree);
     }
 
     public int[] findModel() throws TimeoutException {
         return decorated.findModel();
     }
 
     public IConstr addBlockingClause(IVecInt literals)
             throws ContradictionException {
         return decorated.addBlockingClause(literals);
     }
 
     public boolean removeConstr(IConstr c) {
         return decorated.removeConstr(c);
     }
 
     public int[] findModel(IVecInt assumps) throws TimeoutException {
         return decorated.findModel(assumps);
     }
 
     public IConstr addAtLeast(IVecInt literals, IVec<BigInteger> coeffs,
             BigInteger degree) throws ContradictionException {
         return decorated.addAtLeast(literals, coeffs, degree);
     }
 
     public boolean removeSubsumedConstr(IConstr c) {
         return decorated.removeSubsumedConstr(c);
     }
 
     public int nConstraints() {
         return decorated.nConstraints();
     }
 
     public int newVar(int howmany) {
         return decorated.newVar(howmany);
     }
 
     public void addAllClauses(IVec<IVecInt> clauses)
             throws ContradictionException {
         for (Iterator<IVecInt> it = clauses.iterator(); it.hasNext();) {
             addClause(it.next());
         }
     }
 
     public IConstr addExactly(IVecInt literals, IVecInt coeffs, int weight)
             throws ContradictionException {
         return decorated.addExactly(literals, coeffs, weight);
     }
 
     public int nVars() {
         return decorated.nVars();
     }
 
     @SuppressWarnings("deprecation")
     public void printInfos(PrintWriter out, String prefix) {
         decorated.printInfos(out, prefix);
     }
 
     public IConstr addAtMost(IVecInt literals, int degree)
             throws ContradictionException {
         if (degree == 1) {
             this.atMostOneCstrs.add(literals);
         }
         return decorated.addAtMost(literals, degree);
     }
 
     public IConstr addExactly(IVecInt literals, IVec<BigInteger> coeffs,
             BigInteger weight) throws ContradictionException {
         return decorated.addExactly(literals, coeffs, weight);
     }
 
     public void printInfos(PrintWriter out) {
         decorated.printInfos(out);
     }
 
     public IConstr addAtLeast(IVecInt literals, int degree)
             throws ContradictionException {
         return decorated.addAtLeast(literals, degree);
     }
 
     public void setObjectiveFunction(ObjectiveFunction obj) {
         if (obj != null) {
             IVecInt newVars = new VecInt();
             IVec<BigInteger> newCoeffs = new Vec<BigInteger>();
             Set<Integer> oldVarsToIgnore = new HashSet<Integer>();
             IVecInt oldObjVars = obj.getVars();
             IVec<BigInteger> oldObjCoeffs = obj.getCoeffs();
             int nbReduc;
             nbReduc = processAtMostOneCstrs(obj, newVars, newCoeffs,
                     oldVarsToIgnore);
             System.out.println("c " + nbReduc
                     + " reductions due to atMostOne constraints");
             for (int i = 0; i < oldObjVars.size(); ++i) {
                 if (!oldVarsToIgnore.contains(oldObjVars.get(i))) {
                     newVars.push(oldObjVars.get(i));
                     newCoeffs.push(oldObjCoeffs.get(i));
                 }
             }
             obj = new ObjectiveFunction(newVars, newCoeffs);
         }
         decorated.setObjectiveFunction(obj);
     }
 
     private int processAtMostOneCstrs(ObjectiveFunction obj, IVecInt newVars,
             IVec<BigInteger> newCoeffs, Set<Integer> oldVarsToIgnore) {
         System.out.println("c " + this.atMostOneCstrs.size()
                 + " atMostOne constraints found");
         int nbReduc = 0;
         IVecInt oldObjVars = obj.getVars();
         IVec<BigInteger> oldObjCoeffs = obj.getCoeffs();
         for (IVecInt lits : this.atMostOneCstrs) {
             boolean allLitsIn = true;
             for (IteratorInt it = lits.iterator(); it.hasNext();) {
                 int next = it.next();
                 if (oldVarsToIgnore.contains(next)) {
                     allLitsIn = false;
                     break;
                 }
                 int indexOf = oldObjVars.indexOf(next);
                 if (indexOf == -1
                         || !oldObjCoeffs.get(indexOf).equals(BigInteger.ONE)) {
                     allLitsIn = false;
                     break;
                 }
             }
             if (allLitsIn) {
                 int newObjVar = nextFreeVarId(true);
                 try {
                     for (IteratorInt it = lits.iterator(); it.hasNext();) {
                         int nextInt = it.next();
                         this.decorated.addClause(new VecInt(new int[] {
                                 nextInt, newObjVar }));
                         oldVarsToIgnore.add(Integer.valueOf(nextInt));
                         ++nbReduc;
                     }
                 } catch (ContradictionException e) {
                     // should not occur
                     e.printStackTrace();
                 }
 
                 newVars.push(newObjVar);
                 newCoeffs.push(BigInteger.ONE);
                 --nbReduc;
             }
         }
         return nbReduc;
     }
 
     public ObjectiveFunction getObjectiveFunction() {
         return decorated.getObjectiveFunction();
     }
 
     public IConstr addExactly(IVecInt literals, int n)
             throws ContradictionException {
         return decorated.addExactly(literals, n);
     }
 
     public void setTimeout(int t) {
         decorated.setTimeout(t);
     }
 
     public void setTimeoutOnConflicts(int count) {
         decorated.setTimeoutOnConflicts(count);
     }
 
     public void setTimeoutMs(long t) {
         decorated.setTimeoutMs(t);
     }
 
     public int getTimeout() {
         return decorated.getTimeout();
     }
 
     public long getTimeoutMs() {
         return decorated.getTimeoutMs();
     }
 
     public void expireTimeout() {
         decorated.expireTimeout();
     }
 
     public void reset() {
         decorated.reset();
     }
 
     @SuppressWarnings("deprecation")
     public void printStat(PrintStream out, String prefix) {
         decorated.printStat(out, prefix);
     }
 
     @SuppressWarnings("deprecation")
     public void printStat(PrintWriter out, String prefix) {
         decorated.printStat(out, prefix);
     }
 
     public void printStat(PrintWriter out) {
         decorated.printStat(out);
     }
 
     public Map<String, Number> getStat() {
         return decorated.getStat();
     }
 
     public String toString(String prefix) {
         return decorated.toString(prefix);
     }
 
     public void clearLearntClauses() {
         decorated.clearLearntClauses();
     }
 
     public void setDBSimplificationAllowed(boolean status) {
         decorated.setDBSimplificationAllowed(status);
     }
 
     public boolean isDBSimplificationAllowed() {
         return decorated.isDBSimplificationAllowed();
     }
 
     public <S extends ISolverService> void setSearchListener(
             SearchListener<S> sl) {
         decorated.setSearchListener(sl);
     }
 
     public <S extends ISolverService> SearchListener<S> getSearchListener() {
         return decorated.getSearchListener();
     }
 
     public boolean isVerbose() {
         return decorated.isVerbose();
     }
 
     public void setVerbose(boolean value) {
         decorated.setVerbose(value);
     }
 
     public void setLogPrefix(String prefix) {
         decorated.setLogPrefix(prefix);
     }
 
     public String getLogPrefix() {
         return decorated.getLogPrefix();
     }
 
     public IVecInt unsatExplanation() {
         return decorated.unsatExplanation();
     }
 
     public int[] modelWithInternalVariables() {
         return decorated.modelWithInternalVariables();
     }
 
     public int realNumberOfVariables() {
         return decorated.realNumberOfVariables();
     }
 
     public boolean isSolverKeptHot() {
         return decorated.isSolverKeptHot();
     }
 
     public void setKeepSolverHot(boolean keepHot) {
         decorated.setKeepSolverHot(keepHot);
     }
 
     public ISolver getSolvingEngine() {
         return decorated.getSolvingEngine();
     }
 
 }