/**
 * Copyright (c) 2014,
 *       Charles Prud'homme (TASC, INRIA Rennes, LINA CNRS UMR 6241),
 *       Jean-Guillaume Fages (COSLING S.A.S.).
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the <organization> nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.chocosolver.solver.constraints.unary;

import gnu.trove.map.hash.THashMap;
import gnu.trove.set.hash.TIntHashSet;
import org.chocosolver.solver.Solver;
import org.chocosolver.solver.constraints.Propagator;
import org.chocosolver.solver.constraints.PropagatorPriority;
import org.chocosolver.solver.exception.ContradictionException;
import org.chocosolver.solver.explanations.Deduction;
import org.chocosolver.solver.explanations.Explanation;
import org.chocosolver.solver.explanations.ExplanationEngine;
import org.chocosolver.solver.variables.IntVar;
import org.chocosolver.util.ESat;

import java.util.Arrays;

/**
 * <br/>
 *
 * @author Charles Prud'homme
 * @since 26 nov. 2010
 */
public class PropMemberEnum extends Propagator<IntVar> {

    final TIntHashSet values;


    public PropMemberEnum(IntVar var, int[] values) {
        super(new IntVar[]{var}, PropagatorPriority.UNARY, false);
        this.values = new TIntHashSet(values);
    }

    @Override
    public void propagate(int evtmask) throws ContradictionException {
        int left = Integer.MIN_VALUE;
        int right = left;
        boolean rall = true;
        int ub = this.vars[0].getUB();
        for (int val = this.vars[0].getLB(); val <= ub; val = this.vars[0].nextValue(val)) {
            if (!values.contains(val)) {
                if (val == right + 1) {
                    right = val;
                } else {
                    if (left > Integer.MIN_VALUE) {
                        rall &= vars[0].removeInterval(left, right, aCause);
                    }
                    left = right = val;
                }
            }
        }
        if (left > Integer.MIN_VALUE) {
            rall &= vars[0].removeInterval(left, right, aCause);
        }
        if (rall) {
            this.setPassive();
        }
    }

    @Override
    public void propagate(int varIdx, int mask) throws ContradictionException {
        propagate(0);
    }

    @Override
    public ESat isEntailed() {
        int nb = 0;
        int ub = this.vars[0].getUB();
        for (int val = this.vars[0].getLB(); val <= ub; val = this.vars[0].nextValue(val)) {
            if (values.contains(val)) {
                nb++;
            }
        }
        if (nb == 0) return ESat.FALSE;
        else if (nb == vars[0].getDomainSize()) return ESat.TRUE;
        return ESat.UNDEFINED;
    }

    @Override
    public String toString() {
        return vars[0].getName() + " in " + Arrays.toString(values.toArray());
    }

    @Override
    public void explain(ExplanationEngine xengine, Deduction d, Explanation e) {
        e.add(xengine.getPropagatorActivation(this));
    }

    @Override
    public void duplicate(Solver solver, THashMap<Object, Object> identitymap) {
        if (!identitymap.containsKey(this)) {
            identitymap.put(this, new PropMemberEnum((IntVar) identitymap.get(vars[0]), values.toArray()));
        }
    }
}
