/*    This file is part of the Gudhi Library. The Gudhi library 
 *    (Geometric Understanding in Higher Dimensions) is a generic C++ 
 *    library for computational topology.
 *
 *    Author(s):       David Salinas
 *
 *    Copyright (C) 2014  INRIA Sophia Antipolis-Mediterranee (France)
 *
 *    This program is free software: you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation, either version 3 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef CONTRACTION_POLICIES_EDGE_LENGTH_COST_H_
#define CONTRACTION_POLICIES_EDGE_LENGTH_COST_H_

#include <gudhi/Contraction/policies/Cost_policy.h>

namespace Gudhi {

namespace contraction {

/**
 * @brief return a cost corresponding to the squared length of the edge
 */
template< typename EdgeProfile>
class Edge_length_cost : public Cost_policy<EdgeProfile> {
 public:
  typedef typename Cost_policy<EdgeProfile>::Cost_type Cost_type;
  typedef typename EdgeProfile::Point Point;

  Cost_type operator()(const EdgeProfile& profile, const boost::optional<Point>& placement) const override {
    double res = 0;
    auto p0_coord = profile.p0().begin();
    auto p1_coord = profile.p1().begin();
    for (; p0_coord != profile.p0().end(); p0_coord++, p1_coord++) {
      res += (*p0_coord - *p1_coord) * (*p0_coord - *p1_coord);
    }
    return res;
  }
};

}  // namespace contraction

}  // namespace Gudhi

#endif  // CONTRACTION_POLICIES_EDGE_LENGTH_COST_H_