/*
 * Project: MoleCuilder
 * Description: creates and alters molecular systems
 * Copyright (C)  2012 University of Bonn. All rights reserved.
 * Copyright (C)  2013 Frederik Heber. All rights reserved.
 * Please see the COPYING file or "Copyright notice" in builder.cpp for details.
 * 
 *
 *   This file is part of MoleCuilder.
 *
 *    MoleCuilder 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 2 of the License, or
 *    (at your option) any later version.
 *
 *    MoleCuilder 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 MoleCuilder.  If not, see <http://www.gnu.org/licenses/>. 
 */

/*
 * ConstantPotential.cpp
 *
 *  Created on: May 09, 2013
 *      Author: heber
 */


// include config.h
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "CodePatterns/MemDebug.hpp"

#include "ConstantPotential.hpp"

#include <boost/assign/list_of.hpp> // for 'map_list_of()'
#include <boost/bind.hpp>
#include <boost/lambda/lambda.hpp>
#include <cmath>
#include <string>

#include "CodePatterns/Assert.hpp"

#include "FunctionApproximation/Extractors.hpp"
#include "FunctionApproximation/TrainingData.hpp"
#include "Potentials/helpers.hpp"
#include "Potentials/ParticleTypeCheckers.hpp"
#include "Potentials/InternalCoordinates/OneBody_Constant.hpp"

class Fragment;

// static definitions
const ConstantPotential::ParameterNames_t
ConstantPotential::ParameterNames =
      boost::assign::list_of<std::string>
      ("energy_offset") //
    ;
const std::string ConstantPotential::potential_token("constant");
Coordinator::ptr ConstantPotential::coordinator(Memory::ignore(new OneBody_Constant()));

static BindingModel generateBindingModel(const EmpiricalPotential::ParticleTypes_t &_ParticleTypes)
{
  // fill nodes
  ASSERT( _ParticleTypes.size() <= (size_t)1,
      "generateBindingModel() - ConstantPotential needs zero or one type.");
  BindingModel::vector_nodes_t nodes;
  if (_ParticleTypes.size() == (size_t)1)
    nodes.push_back( FragmentNode(_ParticleTypes.front(), 0) );

  // there are no edges
  HomologyGraph::edges_t edges;

  return BindingModel(nodes, edges);
}

ConstantPotential::ConstantPotential() :
    EmpiricalPotential(),
    params(parameters_t(MAXPARAMS, 0.)),
    bindingmodel(BindingModel())
{
  // have some decent defaults for parameter_derivative checking
  params[energy_offset] = 0.1;
}

ConstantPotential::ConstantPotential(
    const ParticleTypes_t &_ParticleTypes
    ) :
  EmpiricalPotential(_ParticleTypes),
  params(parameters_t(MAXPARAMS, 0.)),
  bindingmodel(generateBindingModel(_ParticleTypes))
{
  // have some decent defaults for parameter_derivative checking
  params[energy_offset] = 0.1;
}

ConstantPotential::ConstantPotential(
    const ParticleTypes_t &_ParticleTypes,
    const double _energy_offset) :
  EmpiricalPotential(_ParticleTypes),
  params(parameters_t(MAXPARAMS, 0.)),
  bindingmodel(generateBindingModel(_ParticleTypes))
{
  params[energy_offset] = _energy_offset;
}

void ConstantPotential::setParameters(const parameters_t &_params)
{
  const size_t paramsDim = _params.size();
  ASSERT( paramsDim <= getParameterDimension(),
      "ConstantPotential::setParameters() - we need not more than "
      +toString(getParameterDimension())+" parameters.");
  for(size_t i=0;i<paramsDim;++i)
    params[i] = _params[i];

#ifndef NDEBUG
  parameters_t check_params(getParameters());
  check_params.resize(paramsDim); // truncate to same size
  ASSERT( check_params == _params,
      "ConstantPotential::setParameters() - failed, mismatch in to be set "
      +toString(_params)+" and set "+toString(check_params)+" params.");
#endif
}

ConstantPotential::results_t
ConstantPotential::operator()(
    const list_of_arguments_t &listarguments
    ) const
{
  // directly set result as energy constant as independent of arg list
  result_t result = params[energy_offset];
  for(list_of_arguments_t::const_iterator iter = listarguments.begin();
      iter != listarguments.end(); ++iter) {
    const arguments_t &arguments = *iter;
    ASSERT( arguments.size() == 0,
        "ConstantPotential::operator() - requires no argument.");
    ASSERT( ParticleTypeChecker::checkArgumentsAgainstParticleTypes(
        arguments, getParticleTypes()),
        "ConstantPotential::operator() - types don't match with ones in arguments.");
    result += 0.;
  }
  return results_t(1, result);
}

ConstantPotential::derivative_components_t
ConstantPotential::derivative(
    const list_of_arguments_t &listarguments
    ) const
{
  result_t result = 0.;
  for(list_of_arguments_t::const_iterator iter = listarguments.begin();
      iter != listarguments.end(); ++iter) {
    const arguments_t &arguments = *iter;
    ASSERT( arguments.size() == 0,
        "ConstantPotential::operator() - requires no argument.");
    ASSERT( ParticleTypeChecker::checkArgumentsAgainstParticleTypes(
        arguments, getParticleTypes()),
        "ConstantPotential::operator() - types don't match with ones in arguments.");
    result += 0.;
  }
  return derivative_components_t(1, result);
}

ConstantPotential::results_t
ConstantPotential::parameter_derivative(
    const list_of_arguments_t &listarguments,
    const size_t index
    ) const
{
  // Maple result: 1
  result_t result = 1.;   // energy_offset
  for(list_of_arguments_t::const_iterator iter = listarguments.begin();
      iter != listarguments.end(); ++iter) {
    const arguments_t &arguments = *iter;
    ASSERT( arguments.size() == 0,
        "ConstantPotential::parameter_derivative() - requires no argument.");
    ASSERT( ParticleTypeChecker::checkArgumentsAgainstParticleTypes(
        arguments, getParticleTypes()),
        "ConstantPotential::operator() - types don't match with ones in arguments.");
//    switch (index) {
//      case energy_offset:
//      {
//        // Maple result: 1
//        result = +1.;
//        break;
//      }
//      default:
//        break;
//    }
  }
  return results_t(1, result);
}

FunctionModel::filter_t ConstantPotential::getSpecificFilter() const
{
  FunctionModel::filter_t returnfunction =
      boost::bind(&Extractors::filterArgumentsByParticleTypes,
          _2, _1,
          boost::cref(getParticleTypes()), boost::cref(getBindingModel()));
  return returnfunction;
}

void
ConstantPotential::setParametersToRandomInitialValues(
    const TrainingData &data)
{
  params[ConstantPotential::energy_offset] =
      data.getTrainingOutputAverage()[0];// -1.;
}