/***************************************************************************
 *             GSkyRegionRect.hpp - rectangular sky region class           *
 * ----------------------------------------------------------------------- *
 * copyright (C) 2019-2020 by Andreas Specovius                            *
 * ----------------------------------------------------------------------- *
 *                                                                         *
 *  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 3 of the License, or      *
 *  (at your option) any later version.                                    *
 *                                                                         *
 *  This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.  *
 *                                                                         *
 ***************************************************************************/
/**
 * @file GSkyRegionRect.hpp
 * @brief Rectangular sky region class interface definition
 * @author Andreas Specovius
 */

#ifndef GSKYREGIONRECT_HPP
#define GSKYREGIONRECT_HPP

/* __ Includes ___________________________________________________________ */
#include <vector>
#include <string>
#include "GMath.hpp"
#include "GSkyDir.hpp"
#include "GSkyRegion.hpp"
#include "GTools.hpp"


/***********************************************************************//**
 * @class GSkyRegionRect
 *
 * @brief Interface for the rectangular sky region class
 *
 * This class provides an implementation for a rectangular sky region. The sky
 * region is defined by an array of parameters, the meaning of which is
 * specific to the derived class where the region type or shape is defined.
 *
 * The class holds several properties such as solid angle subtended by the
 * region and computed through internal method compute_solid().
 *
 * The position angle counts counter-clockwise from celestial North and is
 * aligned with the height axis of the rectangle.
 *
 ***************************************************************************/
class GSkyRegionRect : public GSkyRegion {

public:
    // Constructors and destructors
    GSkyRegionRect(void);
    GSkyRegionRect(const GSkyDir& centre
                  ,const double& w, const double& h
                  ,const double& posang_deg
                  );
    GSkyRegionRect(const double& ra, const double& dec
                  ,const double& w, const double& h
                  ,const double& posang_deg
                  );
    explicit GSkyRegionRect(const std::string& line);
    GSkyRegionRect(const GSkyRegionRect& region);
    virtual ~GSkyRegionRect(void);

    // Operators
    GSkyRegionRect& operator=(const GSkyRegionRect& region);

    // Implemented methods
    void              clear(void);
    GSkyRegionRect*   clone(void) const;
    std::string       classname(void) const;
    double            posang(void) const;
    void              posang(const double& posang);
    double            posang_deg(void) const;
    void              posang_deg(const double& posang);
    double            width(void) const;
    void              width(const double& width);
    double            height(void) const;
    void              height(const double& height);
    const GSkyDir&    centre(void) const;
    void              centre(const GSkyDir& centre);
    void              centre(const double& ra,const double& dec);
    double            ra(void) const;
    double            dec(void) const;
    void              read(const std::string& line);
    std::string       write(void) const;
    bool              contains(const GSkyDir& dir) const;
    bool              contains_local(const GSkyDir& locdir) const;
    bool              contains(const GSkyRegion& reg) const;
    bool              overlaps(const GSkyRegion& reg) const;
    std::string       print(const GChatter& chatter = NORMAL) const;

    GSkyDir           transform_to_local(const GSkyDir& skydir) const;
    GSkyDir           transform_to_global(const GSkyDir& locdir) const;
    GSkyDir           get_corner(const int& index) const;

protected:
    // Protected methods
    void init_members(void);
    void copy_members(const GSkyRegionRect& region);
    void free_members(void);
    void compute_solid_angle(void);
    void update_cache(void);

    // Protected members
    GSkyDir m_centre;     //!< Centre or reference point of the region
    double  m_halfwidth;  //!< Half width of the region [deg]
    double  m_halfheight; //!< Half height of the region [deg]
    double  m_posang;     //!< Position angle, counterclockwise from North [radians]

    double m_posang_cos; //!< Cache for transform_to_local
    double m_posang_sin; //!< Cache for transform_to_local
};


/***********************************************************************//**
 * @brief Return class name
 *
 * @return String containing the class name ("GSkyRegionRect").
 ***************************************************************************/
inline
std::string GSkyRegionRect::classname(void) const
{
    return ("GSkyRegionRect");
}


/***********************************************************************//**
 * @brief Return region position angle (in radians)
 *
 * @return Region position angle [radians].
 *
 * Returns the region position angle in radians. The position angle is
 * counted counterclockwise from North.
 ***************************************************************************/
inline
double GSkyRegionRect::posang(void) const
{
    // Return
    return (m_posang);
}


/***********************************************************************//**
 * @brief Return region position angle (in degrees)
 *
 * @return Region position angle [degrees].
 *
 * Returns the region position angle in degrees. The position angle is
 * counted counterclockwise from North.
 ***************************************************************************/
inline
double GSkyRegionRect::posang_deg(void) const
{
    // Return
    return (m_posang * gammalib::rad2deg);
}


/***********************************************************************//**
 * @brief Return region width extension (in degrees)
 *
 * @return Region width [deg].
 *
 * Returns the region width extension in degrees.
 ***************************************************************************/
inline
double GSkyRegionRect::width(void) const
{
    double width = 2*m_halfwidth;
    return (width);
}


/***********************************************************************//**
 * @brief Return region height extension (in degrees)
 *
 * @return Region height [deg].
 *
 * Returns the region height extension in degrees.
 ***************************************************************************/
inline
double GSkyRegionRect::height(void) const
{
    double height = 2*m_halfheight;
    return (height);
}


/***********************************************************************//**
 * @brief Return rectangular region centre
 *
 * @return Region centre.
 *
 * Returns the region centre.
 ***************************************************************************/
inline
const GSkyDir& GSkyRegionRect::centre(void) const
{
    return (m_centre);
}


/***********************************************************************//**
 * @brief Set rectangular region centre
 *
 * @param[in] dir Region centre.
 *
 * Sets the centre of the rectangular region to the specified sky direction.
 ***************************************************************************/
inline
void GSkyRegionRect::centre(const GSkyDir& dir)
{
    // Set centre
    m_centre = dir;

    // Return
    return;
}


/***********************************************************************//**
 * @brief Set rectangular region centre Right Ascension and Declincation
 *
 * @param[in] ra Right Ascension [deg].
 * @param[in] dec Declination [deg].
 *
 * Sets the centre of the rectangular region to the specified Right Ascension
 * and Declination.
 ***************************************************************************/
inline
void GSkyRegionRect::centre(const double& ra, const double& dec)
{
    // Set centre values
    m_centre.radec_deg(ra,dec);

    // Return
    return;
}


/***********************************************************************//**
 * @brief Return rectangular region centre Right Ascension
 *
 * @return Region centre Right Ascension [deg].
 *
 * Returns the region centre Right Ascension in degrees.
 ***************************************************************************/
inline
double GSkyRegionRect::ra(void) const
{
    return (m_centre.ra_deg());
}


/***********************************************************************//**
 * @brief Return rectangular region centre Declination
 *
 * @return Region centre Declination [deg].
 *
 * Returns the region centre Declination in degrees.
 ***************************************************************************/
inline
double GSkyRegionRect::dec(void) const
{
    return (m_centre.dec_deg());
}

#endif /* GSKYREGIONRECT_HPP */