// -----------------------------------------------------------------------
// fitsHeader.hh: Information about the FITS file's header.
// -----------------------------------------------------------------------
// Copyright (C) 2006, Matthew Whiting, ATNF
//
// This program 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.
//
// Duchamp 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 Duchamp; if not, write to the Free Software Foundation,
// Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA
//
// Correspondence concerning Duchamp may be directed to:
//    Internet email: Matthew.Whiting [at] atnf.csiro.au
//    Postal address: Dr. Matthew Whiting
//                    Australia Telescope National Facility, CSIRO
//                    PO Box 76
//                    Epping NSW 1710
//                    AUSTRALIA
// -----------------------------------------------------------------------
#ifndef FITSHEADER_H
#define FITSHEADER_H

#include <string>
#include <wcslib/wcs.h>
#include <math.h>

namespace duchamp
{


  class Param;

  /**
   *  Class to store FITS header information.
   *
   *   Stores information from a FITS header, including WCS information
   *    in the form of a wcsprm struct, as well as various keywords.
   */
  class FitsHeader
  {

  public:
    FitsHeader();
    virtual ~FitsHeader();
    FitsHeader(const FitsHeader& h);
    FitsHeader& operator= (const FitsHeader& h);

    //--------------------
    // Functions in param.cc
    //
    /** Assign correct WCS parameters.  */
    void    setWCS(struct wcsprm *w);

    /** Return the WCS parameters in a WCSLIB wcsprm struct. */
    struct wcsprm *getWCS();

    /** Provides a reference to the WCS parameters*/
    struct wcsprm& WCS(){ struct wcsprm &rwcs = *wcs; return rwcs; }; 

    // front ends to WCS functions
    /** Convert pixel coords to world coords for a single point. */
    int     wcsToPix(const double *world, double *pix);

    /** Convert pixel coords to world coords for many points. */
    int     wcsToPix(const double *world, double *pix, const int npts);

    /** Convert world coords to pixel coords for a single point. */
    int     pixToWCS(const double *pix, double *world);

    /** Convert world coords to pixel coords for many points. */
    int     pixToWCS(const double *pix, double *world, const int npts);

    /** Convert a (x,y,z) position to a velocity. */
    double  pixToVel(double &x, double &y, double &z);

    /** Convert a set of  (x,y,z) positions to a set of velocities. */
    double *pixToVel(double &x, double &y, double *zarray, int size);

    /** Convert a spectral coordinate to a velocity coordinate.*/
    double  specToVel(const double &z);

    /** Convert a velocity coordinate to a spectral coordinate.*/
    double  velToSpec(const float &vel);

    /** Get an IAU-style name for an equatorial or galactic coordinates. */
    std::string  getIAUName(double ra, double dec);

    /** Correct the units for the spectral axis */
    void    fixUnits(Param &par);
    
    /** Define the units for integrated flux */
    void    setIntFluxUnits();

    //--------------------
    // Functions in FitsIO/headerIO.cc
    //
    /** Read all header info. */
    int     readHeaderInfo(std::string fname, Param &par);

    /** Read BUNIT keyword */
    int     readBUNIT(std::string fname);

    /** Read BLANK & related keywords */
    int     readBLANKinfo(std::string fname, Param &par);

    /** Read beam-related keywords */
    int     readBeamInfo(std::string fname, Param &par);
 
    //--------------------
    // Function in FitsIO/wcsIO.cc
    //
    /** Read the WCS information from a file. */
    int     defineWCS(std::string fname, Param &par);

    //--------------------
    // Basic inline accessor functions
    //
    /** Is the WCS good enough to be used? */
    bool    isWCS(){return wcsIsGood;};
    /** Is the spectral axis OK to be used? */
    bool    isSpecOK(){return (wcs->spec >= 0);};
    bool    canUseThirdAxis(){return ((wcs->spec >= 0)||(naxis>2));};
    int     getNWCS(){return nwcs;};
    void    setNWCS(int i){nwcs=i;};
    int     getNumAxes(){return naxis;};
    void    setNumAxes(int i){naxis=i;};
    std::string  getSpectralUnits(){return spectralUnits;};
    void    setSpectralUnits(std::string s){spectralUnits=s;};
    std::string  getSpectralDescription(){return spectralDescription;};
    void    setSpectralDescription(std::string s){spectralDescription=s;};
    std::string  getFluxUnits(){return fluxUnits;};
    void    setFluxUnits(std::string s){fluxUnits=s;};
    std::string  getIntFluxUnits(){return intFluxUnits;};
    void    setIntFluxUnits(std::string s){intFluxUnits=s;};
    float   getBeamSize(){return beamSize;};
    void    setBeamSize(float f){beamSize=f;};
    float   getBmajKeyword(){return bmajKeyword;};
    void    setBmajKeyword(float f){bmajKeyword=f;};
    float   getBminKeyword(){return bminKeyword;};
    void    setBminKeyword(float f){bminKeyword=f;};
    float   getBpaKeyword(){return bpaKeyword;};
    void    setBpaKeyword(float f){bpaKeyword=f;};
    int     getBlankKeyword(){return blankKeyword;};
    void    setBlankKeyword(int f){blankKeyword=f;};
    float   getBzeroKeyword(){return bzeroKeyword;};
    void    setBzeroKeyword(float f){bzeroKeyword=f;};
    float   getBscaleKeyword(){return bscaleKeyword;};
    void    setBscaleKeyword(float f){bscaleKeyword=f;};

    /** Average the pixel scale (eg arcmin/pix) between the two
	spatial axes, and return. */
    float   getAvPixScale(){
      return sqrt( fabs ( (wcs->pc[0]*wcs->cdelt[0])*
			  (wcs->pc[wcs->naxis+1]*wcs->cdelt[1])));
    };

    bool    needBeamSize();

  private:
    struct wcsprm *wcs;           ///< The WCS parameters for the cube
    ///   in a struct from the wcslib
    ///   library.
    int     nwcs;                 ///< The number of WCS parameters
    bool    wcsIsGood;            ///< A flag indicating whether there
    ///   is a valid WCS present.
    int     naxis;                ///< How many axes are in the header?
    std::string  spectralUnits;        ///< The units of the spectral dimension
    std::string  spectralDescription;  ///< The description of the
    ///   spectral dimension (Frequency,
    ///   Velocity, ...)
    std::string  fluxUnits;       ///< The units of pixel flux (from header)
    std::string  intFluxUnits;    ///< The units of integrated flux (from header)
    float   beamSize;             ///< The calculated beam size in pixels.
    float   bmajKeyword;          ///< The FITS header keyword BMAJ.
    float   bminKeyword;          ///< The FITS header keyword BMIN.
    float   bpaKeyword;           ///< The FITS header keyword BPA.
    int     blankKeyword;         ///< The FITS header keyword BLANK.
    float   bzeroKeyword;         ///< The FITS header keyword BZERO.
    float   bscaleKeyword;        ///< The FITS header keyword BSCALE.
    double  scale;                ///< scale parameter for converting
    ///   spectral coords
    double  offset;               ///< offset parameter for converting
    ///   spectral coords
    double  power;                ///< power parameter for converting
    ///   spectral coords
  };

}

#endif // FITSHEADER_H