/*******************************************************************************
    * 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.reader;
  
  import java.io.IOException;
  import java.io.PrintWriter;
  
  import org.sat4j.core.VecInt;
  import org.sat4j.specs.ContradictionException;
  import org.sat4j.specs.IProblem;
  import org.sat4j.specs.ISolver;
  import org.sat4j.specs.IVecInt;
  import org.sat4j.tools.GateTranslator;
  
  /**
   * Reader for the ASCII And Inverter Graph format defined by Armin Biere.
   * 
   * @author daniel
   * 
   */
  public class AAGReader extends Reader {
  
      private static final int FALSE = 0;
  
      private static final int TRUE = 1;
  
      private final GateTranslator solver;
  
      private int maxvarid;
  
      private int nbinputs;
  
      AAGReader(ISolver s) {
          this.solver = new GateTranslator(s);
      }
  
      @Override
      public String decode(int[] model) {
          StringBuffer stb = new StringBuffer();
          for (int i = 0; i < this.nbinputs; i++) {
              stb.append(model[i] > 0 ? 1 : 0);
          }
          return stb.toString();
      }
  
      @Override
      public void decode(int[] model, PrintWriter out) {
          for (int i = 0; i < this.nbinputs; i++) {
              out.print(model[i] > 0 ? 1 : 0);
          }
      }
  
      @Override
      public IProblem parseInstance(java.io.InputStream in)
              throws ParseFormatException, ContradictionException, IOException {
          EfficientScanner scanner = new EfficientScanner(in);
          String prefix = scanner.next();
          if (!"aag".equals(prefix)) {
              throw new ParseFormatException("AAG format only!");
          }
          this.maxvarid = scanner.nextInt();
          this.nbinputs = scanner.nextInt();
          int nblatches = scanner.nextInt();
          int nboutputs = scanner.nextInt();
          if (nboutputs > 1) {
              throw new ParseFormatException(
                      "CNF conversion allowed for single output circuit only!");
          }
          int nbands = scanner.nextInt();
          this.solver.newVar(this.maxvarid + 1);
          this.solver.setExpectedNumberOfClauses(3 * nbands + 2);
          readInput(this.nbinputs, scanner);
         assert nblatches == 0;
         if (nboutputs > 0) {
             int output0 = readOutput(nboutputs, scanner);
             readAnd(nbands, output0, scanner);
         }
         return this.solver;
     }
 
     private void readAnd(int nbands, int output0, EfficientScanner scanner)
             throws ContradictionException, IOException, ParseFormatException {
 
         for (int i = 0; i < nbands; i++) {
             int lhs = scanner.nextInt();
             int rhs0 = scanner.nextInt();
             int rhs1 = scanner.nextInt();
             this.solver.and(toDimacs(lhs), toDimacs(rhs0), toDimacs(rhs1));
         }
         this.solver.gateTrue(this.maxvarid + 1);
         this.solver.gateTrue(toDimacs(output0));
     }
 
     private int toDimacs(int v) {
         if (v == FALSE) {
             return -(this.maxvarid + 1);
         }
         if (v == TRUE) {
             return this.maxvarid + 1;
         }
         int var = v >> 1;
         if ((v & 1) == 0) {
             return var;
         }
         return -var;
     }
 
     private int readOutput(int nboutputs, EfficientScanner scanner)
             throws IOException, ParseFormatException {
         IVecInt outputs = new VecInt(nboutputs);
         for (int i = 0; i < nboutputs; i++) {
             outputs.push(scanner.nextInt());
         }
         return outputs.get(0);
     }
 
     private IVecInt readInput(int numberOfInputs, EfficientScanner scanner)
             throws IOException, ParseFormatException {
         IVecInt inputs = new VecInt(numberOfInputs);
         for (int i = 0; i < numberOfInputs; i++) {
             inputs.push(scanner.nextInt());
         }
         return inputs;
     }
 }