/*******************************************************************************
 * 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.constraints.pb;

import java.math.BigInteger;

import org.sat4j.core.LiteralsUtils;
import org.sat4j.minisat.constraints.card.AtLeast;
import org.sat4j.minisat.core.ILits;
import org.sat4j.specs.ContradictionException;
import org.sat4j.specs.IVecInt;
import org.sat4j.specs.UnitPropagationListener;

public final class AtLeastPB extends AtLeast implements PBConstr {

    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    private final BigInteger degree;

    private AtLeastPB(ILits voc, IVecInt ps, int degree) {
        super(voc, ps, degree);
        this.degree = BigInteger.valueOf(degree);
    }

    public static PBConstr atLeastNew(UnitPropagationListener s, ILits voc,
            IVecInt ps, int n) throws ContradictionException {
        int degree = niceParameters(s, voc, ps, n);
        if (degree == 0) {
            return new UnitClausesPB(ps);
        }
        if (degree == 1) {
            if (ps.size() == 2) {
                return OriginalBinaryClausePB.brandNewClause(s, voc, ps);
            }
            return OriginalHTClausePB.brandNewClause(s, voc, ps);
        }
        return atLeastNew(voc, ps, degree);
    }

    public static AtLeastPB atLeastNew(ILits voc, IVecInt ps, int n) {
        AtLeastPB atleast = new AtLeastPB(voc, ps, n);
        atleast.register();
        return atleast;
    }

    public BigInteger getCoef(int literal) {
        return BigInteger.ONE;
    }

    public BigInteger getDegree() {
        return this.degree;
    }

    public ILits getVocabulary() {
        return this.voc;
    }

    public int[] getLits() {
        int[] tmp = new int[size()];
        System.arraycopy(this.lits, 0, tmp, 0, size());
        return tmp;
    }

    public BigInteger[] getCoefs() {
        BigInteger[] tmp = new BigInteger[size()];
        for (int i = 0; i < tmp.length; i++) {
            tmp[i] = BigInteger.ONE;
        }
        return tmp;
    }

    /**
     * 
     */
    private boolean learnt = false;

    /**
     * D?termine si la contrainte est apprise
     * 
     * @return true si la contrainte est apprise, false sinon
     * @see org.sat4j.specs.IConstr#learnt()
     */
    @Override
    public boolean learnt() {
        return this.learnt;
    }

    @Override
    public void setLearnt() {
        this.learnt = true;
    }

    @Override
    public void assertConstraint(UnitPropagationListener s) {
        for (int i = 0; i < size(); i++) {
            if (getVocabulary().isUnassigned(get(i))) {
                boolean ret = s.enqueue(get(i), this);
                assert ret;
            }
        }
    }

    public IVecInt computeAnImpliedClause() {
        return null;
    }

    @Override
    public String dump() {
        StringBuilder stb = new StringBuilder();
        stb.append("+1 ");
        stb.append(LiteralsUtils.toOPB(this.lits[0]));
        int i = 1;
        while (i < this.lits.length) {
            stb.append(" +1 "); //$NON-NLS-1$
            stb.append(LiteralsUtils.toOPB(lits[i++]));
        }
        stb.append(" >= "); //$NON-NLS-1$
        stb.append(size() - this.maxUnsatisfied);

        return stb.toString();
    }

    @Override
    public BigInteger getSumCoefs() {
        return BigInteger.valueOf(size());
    }
}
