/* 
 *            Copyright 2009-2018 The VOTCA Development Team
 *                       (http://www.votca.org)
 *
 *      Licensed under the Apache License, Version 2.0 (the "License")
 *
 * You may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *              http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#ifndef VOTCA_XTP_FORCES_H
#define VOTCA_XTP_FORCES_H


#include <votca/xtp/qmatom.h>
#include <votca/xtp/logger.h>
#include <votca/xtp/segment.h>
#include <stdio.h>
#include <votca/xtp/gwbseengine.h>
#include <votca/xtp/qminterface.h>
#include <votca/xtp/statefilter.h>

namespace votca {
    namespace xtp {


        class Forces {
        public:

            Forces(GWBSEEngine& gwbse_engine,const Statefilter& filter)
            : _gwbse_engine(gwbse_engine),_filter(filter),_remove_total_force(false){};

            void Initialize(tools::Property &options);
            void Calculate(const Orbitals& orbitals);

            void setLog(Logger* pLog) {
                _pLog = pLog;
            }

            const Eigen::MatrixX3d& GetForces() const{
                return _forces;
            };
            void Report()const;

        private:
            
            Eigen::Vector3d NumForceForward(Orbitals orbitals,int atom_index);
            Eigen::Vector3d NumForceCentral(Orbitals orbitals,int atom_index);
            void RemoveTotalForce();

            double _displacement;
            std::string _force_method;

            GWBSEEngine& _gwbse_engine;
            const Statefilter& _filter;
            bool _remove_total_force;

            Eigen::MatrixX3d _forces;
            Logger *_pLog;
        };

    }
}
#endif // VOTCA_XTP_FORCES_H