/*
 * Copyright (c) 2011 CTTC
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation;
 *
 * 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Author: Nicola Baldo <nbaldo@cttc.es>
 */

#ifndef COSINE_ANTENNA_MODEL_H
#define COSINE_ANTENNA_MODEL_H

#include <ns3/antenna-model.h>
#include <ns3/object.h>

namespace ns3
{

/**
 * \ingroup antenna
 *
 * \brief Cosine Antenna Model
 *
 * This class implements the cosine model, similarly to what is described in:
 * Cosine Antenna Element, Mathworks, Phased Array System Toolbox (Sep. 2020)
 * Available online: https://www.mathworks.com/help/phased/ug/cosine-antenna-element.html
 *
 * The power pattern of the element is equal to:
  // P(az,el) = cos(az/2)^2m * cos(pi/2 - incl/2)^2n,
  // where az is the azimuth angle, and incl is the inclination angle.
 *
 * Differently from the source, the response is defined for azimuth and elevation angles
 * between –180 and 180 degrees and is always positive.
 * There is no response at the backside of a cosine antenna.
 * The cosine response pattern achieves a maximum value of 1 (0 dB) at 0 degrees azimuth
 * and 90 degrees inclination.
 * An extra settable gain is added to the original model, to improve its generality.
 */
class CosineAntennaModel : public AntennaModel
{
  public:
    /**
     * \brief Get the type ID.
     * \return The object TypeId.
     */
    static TypeId GetTypeId();

    // inherited from AntennaModel
    double GetGainDb(Angles a) override;

    /**
     * Get the vertical 3 dB beamwidth of the cosine antenna model.
     * \return the vertical beamwidth in degrees
     */
    double GetVerticalBeamwidth() const;

    /**
     * Get the horizontal 3 dB beamwidth of the cosine antenna model.
     * \return the horizontal beamwidth in degrees
     */
    double GetHorizontalBeamwidth() const;

    /**
     * Get the horizontal orientation of the antenna element.
     * \return the horizontal orientation in degrees
     */
    double GetOrientation() const;

  private:
    /**
     * Set the vertical 3 dB beamwidth (bilateral) of the cosine antenna model.
     * \param verticalBeamwidthDegrees the vertical beamwidth in degrees
     */
    void SetVerticalBeamwidth(double verticalBeamwidthDegrees);

    /**
     * Set the horizontal 3 dB beamwidth (bilateral) of the cosine antenna model.
     * \param horizontalBeamwidthDegrees the horizontal beamwidth in degrees
     */
    void SetHorizontalBeamwidth(double horizontalBeamwidthDegrees);

    /**
     * Set the horizontal orientation of the antenna element.
     * \param orientationDegrees the horizontal orientation in degrees
     */
    void SetOrientation(double orientationDegrees);

    /**
     * Compute the exponent of the cosine antenna model from the beamwidth
     * \param beamwidthDegrees the beamwidth in degrees
     * \return the exponent
     */
    static double GetExponentFromBeamwidth(double beamwidthDegrees);

    /**
     * Compute the beamwidth of the cosine antenna model from the exponent
     * \param exponent the exponent
     * \return beamwidth in degrees
     */
    static double GetBeamwidthFromExponent(double exponent);

    double m_verticalExponent;   //!< exponent of the vertical direction
    double m_horizontalExponent; //!< exponent of the horizontal direction
    double m_orientationRadians; //!< orientation in radians in the horizontal direction (bearing)
    double m_maxGain;            //!< antenna gain in dB towards the main orientation
};

} // namespace ns3

#endif // COSINE_ANTENNA_MODEL_H
