// -*- mode: c++; c-indent-level: 4; c++-member-init-indent: 8; comment-column: 35; -*-

//-----------------------------------------------------------------------------
// FlowShopOpCrossoverQuad.h
// (c) OPAC Team (LIFL), Dolphin Project (INRIA), 2007
/*
    This library...

    Contact: paradiseo-help@lists.gforge.inria.fr, http://paradiseo.gforge.inria.fr
 */
//-----------------------------------------------------------------------------

#ifndef FLOWSHOPOPCROSSOVERQUAD_H_
#define FLOWSHOPOPCROSSOVERQUAD_H_

#include <eoOp.h>
#include "FlowShop.h"

/**
 * Functor
 * Quadratic crossover operator for flow-shop (modify the both genotypes)
 */
class FlowShopOpCrossoverQuad: public eoQuadOp<FlowShop> {

public:

    /**
     * default constructor
     */
    FlowShopOpCrossoverQuad() {}

    /**
     * the class name (used to display statistics)
     */
    string className() const {
        return "FlowShopOpCrossoverQuad";
    }

    /**
     * eoQuad crossover - _genotype1 and _genotype2 are the (future) offspring, i.e. _copies_ of the parents
     * @param FlowShop & _genotype1  the first parent
     * @param FlowShop & _genotype2  the second parent
     */
    bool operator()(FlowShop & _genotype1, FlowShop & _genotype2) {
        bool oneAtLeastIsModified;

        // parents
        vector<unsigned> parent1 = _genotype1.getScheduling();
        vector<unsigned> parent2 = _genotype2.getScheduling();

        // computation of the 2 random points
        unsigned point1, point2;
        do {
            point1 =  rng.random(min(parent1.size(), parent2.size()));
            point2 =  rng.random(min(parent1.size(), parent2.size()));
        } while (fabs((double) point1-point2) <= 2);

        // computation of the offspring
        vector<unsigned> offspring1 = generateOffspring(parent1, parent2, point1, point2);
        vector<unsigned> offspring2 = generateOffspring(parent2, parent1, point1, point2);

        // does at least one genotype has been modified ?
        if ((parent1 != offspring1) || (parent2 != offspring2)) {
            // update
            _genotype1.setScheduling(offspring1);
            _genotype2.setScheduling(offspring2);
            // at least one genotype has been modified
            oneAtLeastIsModified = true;
        }
        else {
            // no genotype has been modified
            oneAtLeastIsModified = false;
        }

        // return 'true' if at least one genotype has been modified
        return oneAtLeastIsModified;
    }


private:

    /**
     * generation of an offspring by a 2 points crossover
     * @param vector<unsigned> _parent1  the first parent
     * @param vector<unsigned> _parent2  the second parent
     * @param unsigned_point1  the first point
     * @param unsigned_point2  the second point
     */
    vector<unsigned> generateOffspring(vector<unsigned> _parent1, vector<unsigned> _parent2, unsigned _point1, unsigned _point2) {
        vector<unsigned> result = _parent1;
        vector<bool> taken_values(result.size(), false);
        if (_point1 > _point2) swap(_point1, _point2);

        /* first parent */
        for (unsigned i=0 ; i<=_point1 ; i++) {
            // result[i] == _parent1[i]
            taken_values[_parent1[i]] = true;
        }
        for (unsigned i=_point2 ; i<result.size() ; i++) {
            // result[i] == _parent1[i]
            taken_values[_parent1[i]] = true;
        }

        /* second parent */
        unsigned i = _point1+1;
        unsigned j = 0;
        while (i<_point2 && j<_parent2.size()) {
            if (! taken_values[_parent2[j]]) {
                result[i] = _parent2[j];
                i++;
            }
            j++;
        }

        return result;
    }

};

#endif /*FLOWSHOPOPCROSSOVERQUAD_H_*/