/*
 * VectorContent.hpp
 *
 *  Created on: Jul 2, 2010
 *      Author: crueger
 */

#ifndef VECTORCONTENT_HPP_
#define VECTORCONTENT_HPP_

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


/**
 * !file
 * The way GSL works does not allow for forward definitions of the structures.
 * Because of this the pointer to the gsl_vector struct is wrapped inside another
 * (dumb) object that allows for forward definitions.
 *
 * DO NOT USE OUTSIDE OF VECTOR UNLESS YOU ABSOLUTELY HAVE TO AND KNOW WHAT YOU ARE DOING.
 */

#include <iosfwd>

#include <gsl/gsl_vector.h>

#include "LinearAlgebra/MatrixVector_ops.hpp"

class Vector;
class MatrixContent;

/** Dummy structure to create a unique signature.
 *
 */
struct VectorBaseCase{};

class VectorContent{
  friend std::ostream & operator<< (std::ostream& ost, const VectorContent &m);
  friend VectorContent const operator*(const VectorContent& a, const double m);
  friend VectorContent const operator*(const double m, const VectorContent& a);
  friend VectorContent const operator+(const VectorContent& a, const VectorContent& b);
  friend VectorContent const operator-(const VectorContent& a, const VectorContent& b);

  // matrix vector products
  friend VectorContent const operator*(const VectorContent& vec, const MatrixContent& mat);
  friend VectorContent const operator*(const MatrixContent& mat, const VectorContent& vec);

public:
  explicit VectorContent(size_t _dim);
  VectorContent(VectorBaseCase);
  VectorContent(const VectorContent * const src);
  VectorContent(const VectorContent & src);
  VectorContent(gsl_vector * _src);
  virtual ~VectorContent();

  // Accessing
  double &at(size_t m);
  const double at(size_t m) const;
  double & operator[](size_t i);
  const double operator[](size_t i) const;
  double *Pointer(size_t m) const;
  const double *const_Pointer(size_t m) const;

  // Assignment operator
  VectorContent &operator=(const VectorContent& src);

  // Initializing
  void setFromDoubleArray(double * x);
  void setFromVector(Vector &v);
  void setValue(double x);
  void setZero();
  int setBasis(size_t m);

  // Exchanging elements
  int SwapElements(size_t i, size_t j);
  int Reverse();

  // checking state
  bool IsZero() const;
  bool IsOne() const;

  // properties
  //bool IsNormalTo(const VectorContent &normal) const;
  //bool IsEqualTo(const VectorContent &a) const;

  // Norms
  double Norm() const;
  double NormSquared() const;
  void Normalize();
  VectorContent getNormalized() const;

  // properties relative to another VectorContent
  double DistanceSquared(const VectorContent &y) const;
  double ScalarProduct(const VectorContent &y) const;
  double Angle(const VectorContent &y) const;

  // operators
  bool operator==(const VectorContent& b) const;
  const VectorContent& operator+=(const VectorContent& b);
  const VectorContent& operator-=(const VectorContent& b);
  const VectorContent& operator*=(const double m);
  const double operator*(const VectorContent& b) const;

  const size_t getDimension() const;

  size_t dimension;
  gsl_vector *content;
private:
};

std::ostream & operator << (std::ostream& ost, const VectorContent &m);
VectorContent const operator*(const VectorContent& a, const double m);
VectorContent const operator*(const double m, const VectorContent& a);
VectorContent const operator+(const VectorContent& a, const VectorContent& b);
VectorContent const operator-(const VectorContent& a, const VectorContent& b);

/** Vector view.
 * Extension of VectorContent to contain not a gsl_vector but only a view on a
 * gsl_vector (or row/column in a gsl_matrix).
 *
 * We need the above VectorBaseCase here:
 * content, i.e. the gsl_vector, must not be allocated, as it is just a view
 * with an internal gsl_vector_view. Hence, VectorBaseCase is just dummy class
 * to give the constructor a unique signature.
 */
struct VectorViewContent : public VectorContent
{
  VectorViewContent(gsl_vector_view _view) :
    VectorContent(VectorBaseCase()),
    view(_view)
  {
    dimension = _view.vector.size;
    content=&view.vector;
  }
  ~VectorViewContent(){
    content=0;
  }
  gsl_vector_view view;
};

#endif /* VECTORCONTENT_HPP_ */