/*******************************************************************************
    * 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.ConstrGroup;
  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.IVec;
  import org.sat4j.specs.IVecInt;
  import org.sat4j.tools.xplain.Xplain;
  
  public class XplainPB extends Xplain<IPBSolver> implements IPBSolver {
  
      /**
  	 * 
  	 */
      private static final long serialVersionUID = 1L;
  
      public XplainPB(IPBSolver solver) {
          super(solver);
      }
  
      @Override
      public IConstr addAtLeast(IVecInt literals, int degree)
              throws ContradictionException {
          IVecInt coeffs = new VecInt(literals.size(), 1);
          int newvar = createNewVar(literals);
          literals.push(newvar);
          coeffs.push(coeffs.size() - degree);
          IConstr constr = decorated().addAtLeast(literals, coeffs, degree);
          if (constr == null) {
              // constraint trivially satisfied
              discardLastestVar();
          } else {
              getConstrs().put(newvar, constr);
          }
          return constr;
      }
  
      @Override
      public IConstr addAtMost(IVecInt literals, int degree)
              throws ContradictionException {
          IVecInt coeffs = new VecInt(literals.size(), 1);
          int newvar = createNewVar(literals);
          literals.push(newvar);
          coeffs.push(degree - coeffs.size());
          IConstr constr = decorated().addAtMost(literals, coeffs, degree);
          if (constr == null) {
              // constraint trivially satisfied
              discardLastestVar();
          } else {
              getConstrs().put(newvar, constr);
          }
          return constr;
      }
  
      @Override
      public IConstr addExactly(IVecInt literals, int n)
              throws ContradictionException {
          int newvar = createNewVar(literals);
  
          // at most
          IVecInt coeffs = new VecInt(literals.size(), 1);
          literals.push(newvar);
          coeffs.push(n - coeffs.size());
         IConstr constr1 = decorated().addAtMost(literals, coeffs, n);
         // at least
         coeffs.pop();
         coeffs.push(coeffs.size() - n);
         IConstr constr2 = decorated().addAtLeast(literals, coeffs, n);
         if (constr1 == null && constr2 == null) {
             discardLastestVar();
             return null;
         }
         ConstrGroup group = new ConstrGroup();
         group.add(constr1);
         group.add(constr2);
         getConstrs().put(newvar, group);
         return group;
     }
 
     public IConstr addPseudoBoolean(IVecInt lits, IVec<BigInteger> coeffs,
             boolean moreThan, BigInteger d) throws ContradictionException {
         int newvar = createNewVar(lits);
         lits.push(newvar);
         if (moreThan && d.signum() >= 0) {
             coeffs.push(d);
         } else {
             BigInteger sum = BigInteger.ZERO;
             for (Iterator<BigInteger> ite = coeffs.iterator(); ite.hasNext();) {
                 sum = sum.add(ite.next());
             }
             sum = sum.subtract(d);
             coeffs.push(sum.negate());
         }
         IConstr constr = decorated()
                 .addPseudoBoolean(lits, coeffs, moreThan, d);
         if (constr == null) {
             // constraint trivially satisfied
             discardLastestVar();
             // System.err.println(lits.toString()+"/"+coeffs+"/"+(moreThan?">=":"<=")+d);
         } else {
             getConstrs().put(newvar, constr);
         }
         return constr;
     }
 
     public void setObjectiveFunction(ObjectiveFunction obj) {
         decorated().setObjectiveFunction(obj);
     }
 
     public ObjectiveFunction getObjectiveFunction() {
         return decorated().getObjectiveFunction();
     }
 
     public IConstr addAtMost(IVecInt literals, IVecInt coeffs, int degree)
             throws ContradictionException {
         throw new UnsupportedOperationException();
     }
 
     public IConstr addAtMost(IVecInt literals, IVec<BigInteger> coeffs,
             BigInteger degree) throws ContradictionException {
         throw new UnsupportedOperationException();
     }
 
     public IConstr addAtLeast(IVecInt literals, IVecInt coeffs, int degree)
             throws ContradictionException {
         throw new UnsupportedOperationException();
     }
 
     public IConstr addAtLeast(IVecInt literals, IVec<BigInteger> coeffs,
             BigInteger degree) throws ContradictionException {
         throw new UnsupportedOperationException();
     }
 
     public IConstr addExactly(IVecInt literals, IVecInt coeffs, int weight)
             throws ContradictionException {
         throw new UnsupportedOperationException();
     }
 
     public IConstr addExactly(IVecInt literals, IVec<BigInteger> coeffs,
             BigInteger weight) throws ContradictionException {
         throw new UnsupportedOperationException();
     }
 }