/*******************************************************************************
   * SAT4J: a SATisfiability library for Java Copyright (C) 2004-2008 Daniel Le Berre
   *
   * 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++.
  * 
  *******************************************************************************/
  package org.sat4j.tools;
  
  import java.io.ObjectInputStream;
  import java.io.PrintStream;
  import java.io.PrintWriter;
  import java.util.Map;
  
  import org.sat4j.specs.ContradictionException;
  import org.sat4j.specs.IConstr;
  import org.sat4j.specs.ISolver;
  import org.sat4j.specs.IVec;
  import org.sat4j.specs.IVecInt;
  import org.sat4j.specs.IteratorInt;
  import org.sat4j.specs.TimeoutException;
  
  /**
   * Solver used to display in a writer the CNF instance in Dimacs format.
   * 
   * That solver is useful to produce CNF files to be used by third party solvers.
   * 
   * @author leberre
   * 
   */
  public class DimacsOutputSolver implements ISolver {
  
      /**
       * 
       */
      private static final long serialVersionUID = 1L;
  
      private transient PrintWriter out;
  
      private int nbvars;
  
      private int nbclauses;
  
      private boolean fixedNbClauses = false;
  
      private boolean firstConstr = true;
      
      public DimacsOutputSolver() {
          this(new PrintWriter(System.out, true));
      }
  
      public DimacsOutputSolver(PrintWriter pw) {
          out = pw;
      }
  
      private void readObject(ObjectInputStream stream) {
          out = new PrintWriter(System.out, true);
      }
  
      public int newVar() {
          return 0;
      }
  
      public int newVar(int howmany) {
          out.print("p cnf " + howmany);
          nbvars = howmany;
          return 0;
      }
  
      public void setExpectedNumberOfClauses(int nb) {
          out.println(" " + nb);
          nbclauses = nb;
          fixedNbClauses = true;
      }
  
      public IConstr addClause(IVecInt literals) throws ContradictionException {
          if (firstConstr) {
              if (!fixedNbClauses) {
                  out.println(" XXXXXX");
             }
             firstConstr = false;
         }
         for (IteratorInt iterator = literals.iterator();iterator.hasNext();)
             out.print(iterator.next() + " ");
         out.println("0");
         return null;        
     }
 
     public boolean removeConstr(IConstr c) {
         throw new UnsupportedOperationException();
     }
 
     public void addAllClauses(IVec<IVecInt> clauses)
             throws ContradictionException {
         throw new UnsupportedOperationException();
     }
 
     public IConstr addAtMost(IVecInt literals, int degree)
             throws ContradictionException {
         if (degree > 1) {
             throw new UnsupportedOperationException(
                     "Not a clausal problem! degree " + degree);
         }
         assert degree == 1;
         if (firstConstr) {
             if (!fixedNbClauses) {
                 out.println("XXXXXX");
             }
             firstConstr = false;
         }
         for (int i = 0; i <= literals.size(); i++) {
             for (int j = i + 1; j < literals.size(); j++) {
                 out.println("" + (-literals.get(i)) + " " + (-literals.get(j))
                         + " 0");
             }
         }
         return null;
     }
 
     public IConstr addAtLeast(IVecInt literals, int degree)
             throws ContradictionException {
         if (degree > 1) {
             throw new UnsupportedOperationException(
                     "Not a clausal problem! degree " + degree);
         }
         assert degree == 1;
         return addClause(literals);
     }
 
     public void setTimeout(int t) {
         // TODO Auto-generated method stub
     }
 
     public void setTimeoutMs(long t) {
         // TODO Auto-generated method stub
     }
 
     public int getTimeout() {
         return 0;
     }
 
     public long getTimeoutMs() {
         return 0L;
     }
     
     public void reset() {
         fixedNbClauses = false;
         firstConstr  = true;
 
     }
 
     public void printStat(PrintStream output, String prefix) {
         // TODO Auto-generated method stub
 
     }
 
     public void printStat(PrintWriter output, String prefix) {
         // TODO Auto-generated method stub
 
     }
 
     public Map<String, Number> getStat() {
         // TODO Auto-generated method stub
         return null;
     }
 
     public String toString(String prefix) {
         return "Dimacs output solver";
     }
 
     public void clearLearntClauses() {
         // TODO Auto-generated method stub
 
     }
 
     public int[] model() {
         throw new UnsupportedOperationException();
     }
 
     public boolean model(int var) {
         throw new UnsupportedOperationException();
     }
 
     public boolean isSatisfiable() throws TimeoutException {
         throw new TimeoutException("There is no real solver behind!");
     }
 
     public boolean isSatisfiable(IVecInt assumps) throws TimeoutException {
         throw new TimeoutException("There is no real solver behind!");
     }
 
     public int[] findModel() throws TimeoutException {
         throw new UnsupportedOperationException();
     }
 
     public int[] findModel(IVecInt assumps) throws TimeoutException {
         throw new UnsupportedOperationException();
     }
 
     public int nConstraints() {
         return nbclauses;
     }
 
     public int nVars() {
        return nbvars;
     }
 
     public void expireTimeout() {
         // TODO Auto-generated method stub
         
     }
 
     public boolean isSatisfiable(IVecInt assumps, boolean global)
             throws TimeoutException {
         throw new TimeoutException("There is no real solver behind!");
     }
 
     public boolean isSatisfiable(boolean global) throws TimeoutException {
         throw new TimeoutException("There is no real solver behind!");
     }
 
     public void printInfos(PrintWriter output, String prefix) {
     }
 
     public void setTimeoutOnConflicts(int count) {        
     }
 
 	public boolean isDBSimplificationAllowed() {
 		return false;
 	}
 
 	public void setDBSimplificationAllowed(boolean status) {
 	}
 
 }