/*
 * SamplingGrid.hpp
 *
 *  Created on: 25.07.2012
 *      Author: heber
 */

#ifndef SAMPLINGGRID_HPP_
#define SAMPLINGGRID_HPP_

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

#include <iosfwd>
#include <vector>

#include "boost/serialization/export.hpp"
#include "boost/serialization/vector.hpp"

#include "Jobs/Grid/SamplingGridProperties.hpp"

class MPQCData;
class SamplingGridTest;

/** This class stores a sample function on a three-dimensional grid.
 *
 *  \note We do not use boost::multi_array because it is not trivial to serialize.
 *
 */
class SamplingGrid : public SamplingGridProperties
{
  //!> grant unit test access to private parts
  friend class SamplingGridTest;
  //!> grant output operator access
  friend std::ostream & operator<<(std::ostream &ost, const SamplingGrid& other);
public:
  //!> typedef for sampled values
  typedef std::vector< double > sampledvalues_t;

  /** Constructor for class SamplingGrid.
   *
   * \param _begin offset for grid per axis
   * \param _end edge length of grid per axis
   * \param _level number of grid points in \f$2^{\mathrm{level}}\f$
   * \param _sampled_grid sample points
   */
  SamplingGrid(const double _begin[3],
      const double _end[3],
      const int _level,
      const sampledvalues_t &_sampled_grid);

  /** Copy constructor for class SamplingGrid.
   *
   * \param _grid grid to copy
   */
  SamplingGrid(const SamplingGrid &_grid);

  /** Copy constructor for class SamplingGrid from SamplingGridProperties.
   *
   * \param _props properties to copy
   */
  SamplingGrid(const SamplingGridProperties &_props);

  /** Copy constructor for class SamplingGrid from SamplingGridProperties.
   *
   * \param _props properties to copy
   * \param _sampled_grid sample points
   */
  SamplingGrid(
      const SamplingGridProperties &_props,
      const sampledvalues_t &_sampled_grid);

  /** default cstor.
   */
  SamplingGrid();

  virtual ~SamplingGrid();

  /** Assignment operator.
   *
   * \param other other instance to assign ourselves to
   */
  SamplingGrid& operator=(const SamplingGrid& other);

  /** Addition operator with another SamplingGrid instance \a other.
   *
   * \param other other instance to sum onto this one.
   * \return ref to this instance
   */
  SamplingGrid& operator+=(const SamplingGrid& other)
  {
    superposeOtherGrids(other, +1.);
    return *this;
  }

  /** Element-wise multiplication operator with another SamplingGrid instance \a other.
   *
   * \param other other instance to sum onto this one.
   * \return ref to this instance
   */
  SamplingGrid& operator*=(const SamplingGrid& other);

  /** Subtraction operator with another SamplingGrid instance \a other.
   *
   * \param other other instance to subtract from this one.
   * \return ref to this instance
   */
  SamplingGrid& operator-=(const SamplingGrid& other)
  {
    superposeOtherGrids(other, -1.);
    return *this;
  }

  /** Returns the numeric integral over the grid.
   *
   * @return sum of grid values times volume element
   */
  double integral() const;

  /** Returns the numeric integral over the grid where the grid is element-wise multiplied with \a weight.
   *
   * @param weight grid of weights
   * @return sum of grid values weighted by respective element in weight times volume element
   */
  double integral(const SamplingGrid &weight) const;

  /** Returns the volume of the domain for this sampled function.
   *
   * @return volume
   */
  const double getVolume() const;

  /** Returns the total number of gridpoints of the discrete mesh covering the (window) volume.
   *
   * @return number of gridpoints sampled_values should have
   */
  const size_t getWindowGridPoints() const;

  /** Returns the total number of gridpoints of the discrete mesh covering the volume.
   *
   * @return number of gridpoints sampled_values should have
   */
  const size_t getTotalGridPoints() const;

  /** Returns the number of grid points per axis.
   *
   * @return number of grid points per unit length
   */
  const size_t getGridPointsPerAxis() const;

  /** Returns the volume of the domain covered by the current window.
   *
   * @return volume of window
   */
  const double getWindowVolume() const;

private:
  /** Sets the size of the window.
   *
   * \note also resets the sampled points so far.
   *
   * \param _begin_window start of new window
   * \param _end_window end of window
   */
  void setWindow(const double _begin_window[3], const double _end_window[3]);

  /** Sets the size of the domain.
   *
   * \note also resets the sampled points so far and the window.
   *
   * \param _begin start of new window
   * \param _end end of window
   */
  void setDomain(const double _begin[3], const double _end[3]);

  /** Sets the size of the domain.
   *
   * \note this is just internally used for easing the array setting.
   *
   * \param _begin start of domain
   * \param _end end of domain
   */
  void setDomainSize(const double _begin[3], const double _end[3]);

  /** Extends the window while keeping the values.
   *
   * \param _begin_window new start of window
   * \param _end_window new end of window
   */
  void extendWindow(const double _begin_window[3], const double _end_window[3]);

  /** Adds another window onto the one in this instance.
   *
   * \note We assume here that the given window fits on the this one.
   *
   * \param _begin_window start of other window
   * \param _end_window end of other window
   * \param _sampled_grid other set of sampled values
   */
  void addOntoWindow(
      const double _begin_window[3],
      const double _end_window[3],
      const sampledvalues_t &_sampled_grid);

  /** Helper function that contains all the logic of how to superpose two
   * grids.
   *
   * Is called by SamplingGrid::operator+=() and SamplingGrid::operator-=()
   *
   * @param other other histogram
   * @param prefactor +1. is then addition, -1. is subtraction.
   */
  void superposeOtherGrids(const SamplingGrid &other, const double prefactor);

  /** Sets the size of the window.
   *
   * \note also resets the sampled points so far.
   *
   * \param _begin_window start of new window
   * \param _end_window end of window
   */
  void setWindowSize(const double _begin_window[3], const double _end_window[3]);

public:
  /// We do not store the whole grid if many entries are actually zero
  /// but only a window wherein the sampled function is non-zero.

  //!> sample points of the window
  sampledvalues_t sampled_grid;

  //!> start of the window relative to SamplingGridProperties::begin and SamplingGridProperties::size
  double begin_window[3];
  //!> end of the window relative to SamplingGridProperties::begin and SamplingGridProperties::size
  double end_window[3];

private:
  friend class MPQCData;

  friend class boost::serialization::access;
  // serialization
  template <typename Archive>
  void serialize(Archive& ar, const unsigned int version)
  {
    ar & boost::serialization::base_object<SamplingGridProperties>(*this);
    ar & const_cast< sampledvalues_t &>(sampled_grid);
    for(size_t i=0;i<3;++i) {
      ar & begin_window[i];
      ar & end_window[i];
    }
  }

  //!> static typedef to use in cstor when no initial values are given
  static const double zeroOffset[3];
};

/** Output operator for class SamplingGrid.
 *
 * \param ost output stream to print to
 * \param other instance to print
 * \return ref to stream for concatenation
 */
std::ostream & operator<<(std::ostream &ost, const SamplingGrid& other);

template<typename T> T ZeroInstance();
template<> SamplingGrid ZeroInstance<SamplingGrid>();

// we need to give this class a unique key for serialization
// its is only serialized through its base class FragmentJob
BOOST_CLASS_EXPORT_KEY(SamplingGrid)

#endif /* SAMPLINGGRID_HPP_ */