/*
 * IndexedPartialCharges.hpp
 *
 *  Created on: Jun 12, 2016
 *      Author: heber
 */


#ifndef INDEXEDPARTIALCHARGES_HPP_
#define INDEXEDPARTIALCHARGES_HPP_

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

#include <iosfwd>

#include "Fragmentation/Summation/SetValues/IndexedValue.hpp"
#include "Fragmentation/Summation/ZeroInstance.hpp"

struct partial_charge_t
{
  //!> typedef for a single charge
  typedef double charge_t;
  charge_t charge;

  /** Default constructor for a partial charge.
   */
  partial_charge_t() :
    charge(0.)
  {}

  /** Constructor for a partial charge.
   *
   * \param _charge new partial charge
   */
  partial_charge_t(const double &_charge) :
    charge(_charge)
  {}

  /** Assignment operator for the charge.
   *
   * \param _charge new partial charge
   */
  partial_charge_t& operator()(const double &_charge)
  {
    charge = _charge;
    return *this;
  }

  /** Sum operator.
   *
   * \param _charge new partial charge
   */
  partial_charge_t& operator+=(const double &_charge)
  { charge += _charge; return *this; }

  /** Subtraction operator.
   *
   * \param _charge new partial charge
   */
  partial_charge_t& operator-=(const double &_charge)
  { charge -= _charge; return *this; }

  /** Comparator for partial charge.
   *
   * \param other other charge instance
   */
  bool operator==(const partial_charge_t &other) const
  { return charge == other.charge; }

  bool operator!=(const partial_charge_t &other) const
  { return !operator==(other); }

  bool operator<(const partial_charge_t &other) const
  { return charge < other.charge; }

  /** Summation operator for two force vectors.
   *
   * \param other other charge
   * \param prefactor prefactor to use in summation (e.g. -1 gives a subtraction)
   */
  void superposeOtherIndexedVectors(const partial_charge_t &other, const double prefactor)
  { charge = charge + prefactor * other.charge; }

  // make output operator friend
  friend std::ostream & operator<<(std::ostream &ost, const partial_charge_t &other);
};

std::ostream & operator<<(std::ostream &ost, const partial_charge_t &other);

struct IndexedPartialCharges  : public IndexedValue<partial_charge_t>
{
public:
  IndexedPartialCharges(
    const typename IndexedValue<partial_charge_t>::indices_t &_indices,
    const typename IndexedValue<partial_charge_t>::values_t &_charges) :
    IndexedValue<partial_charge_t>(_indices, _charges)
    {}

  IndexedPartialCharges()
  {}
};

template<typename T> T ZeroInstance();
template<> IndexedPartialCharges ZeroInstance< IndexedPartialCharges >();
template<> partial_charge_t ZeroInstance< partial_charge_t >();

#endif /* INDEXEDPARTIALCHARGES_HPP_ */