/*
 * This file is part of the Owl Positioning System (OwlPS).
 * OwlPS is a project of the University of Franche-Comté
 * (Université de Franche-Comté), France.
 */


#ifndef _OWLPS_POSITIONING_POSUTIL_HH_
#define _OWLPS_POSITIONING_POSUTIL_HH_

class Measurement ;

#include <boost/tr1/unordered_map.hpp>
#include <boost/algorithm/string/case_conv.hpp>

/// Utilitary class
class PosUtil
{
public:
  /// The speed of light, in m/s
  static const unsigned long LIGHT_SPEED = 299792458 ;

  /** @name Maths */
  //@{
  /// Returns the radian value of \em degrees
  static double deg2rad(const double &degrees) ;
  /// Returns the degree value of \em radians
  static double rad2deg(const double &radians) ;
  /// Checks if \em value is in the interval [center-width;center+width]
  static bool is_in_interval(float center, float bound, float value) ;
  //@}

  /** @name Measurements */
  //@{
  /// Mutually completes two Measurement lists with missing APs
  static void complete_with_dummy_measurements(
    std::tr1::unordered_map<std::string, Measurement> &measurements1,
    std::tr1::unordered_map<std::string, Measurement> &measurements2) ;
  /// Computes the similarity of two Measurement lists
  static float similarity(
    std::tr1::unordered_map<std::string, Measurement> &measurements1,
    std::tr1::unordered_map<std::string, Measurement> &measurements2) ;
  //@}

  /** @name Wi-Fi */
  //@{
  /// Converts a Wi-Fi channel to the corresponding frequency in Hz
  static unsigned long wifi_channel_to_hz(const unsigned long &channel) ;
  //@}

  /** @name Strings */
  //@{
  static void to_upper(std::string &str) ;
  static void assert_uppercase(const std::string &str) ;
  static std::string int_to_mac(const uint32_t source) ;
  //@}
} ;



/* *** Maths *** */


/**
 * This function checks if \em value belongs to the symmetrical interval
 * [center-bound;center+bound].
 *
 * @arg center The center of the interval.
 * @arg bound Half the width of the interval.
 * @arg value The value to check the presence in the interval.
 *
 * @returns \em true if value belongs to the interval.
 * @returns \em false if value does not belong to the interval.
 */
inline bool PosUtil::
is_in_interval(float center, float bound, float value)
{
  assert(bound > 0) ;
  float interval_min = center - bound ;
  float interval_max = center + bound ;
  return interval_min <= value && value <= interval_max ;
}



/* *** Strings *** */


inline void PosUtil::to_upper(std::string &str)
{
  boost::to_upper(str) ;
}


inline void PosUtil::assert_uppercase(const std::string &str)
{
#ifndef NDEBUG
  std::string str_up(str) ;
  to_upper(str_up) ;
  assert(str_up == str) ;
#endif // NDEBUG
}



#endif // _OWLPS_POSITIONING_POSUTIL_HH_