/*
 * This file is part of the Owl Positioning System (OwlPS).
 * OwlPS is a project of the University of Franche-Comte
 * (Université de Franche-Comté), France.
 *
 * Copyright © Université de Franche-Comté 2007-2012.
 *
 * Corresponding author: Matteo Cypriani <mcy@lm7.fr>
 *
 ***********************************************************************
 *
 * This software is governed by the CeCILL license under French law and
 * abiding by the rules of distribution of free software. You can use,
 * modify and/or redistribute the software under the terms of the CeCILL
 * license as circulated by CEA, CNRS and INRIA at the following URL:
 * http://www.cecill.info
 *
 * As a counterpart to the access to the source code and rights to copy,
 * modify and redistribute granted by the license, users are provided
 * only with a limited warranty and the software's authors, the holder
 * of the economic rights, and the successive licensors have only
 * limited liability.
 *
 * In this respect, the user's attention is drawn to the risks
 * associated with loading, using, modifying and/or developing or
 * reproducing the software by the user in light of its specific status
 * of free software, that may mean that it is complicated to manipulate,
 * and that also therefore means that it is reserved for developers and
 * experienced professionals having in-depth computer knowledge. Users
 * are therefore encouraged to load and test the software's suitability
 * as regards their requirements in conditions enabling the security of
 * their systems and/or data to be ensured and, more generally, to use
 * and operate it in the same conditions as regards security.
 *
 * The fact that you are presently reading this means that you have had
 * knowledge of the CeCILL license and that you accept its terms.
 *
 ***********************************************************************
 */


#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 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)
{
  if (bound == 0)
    return value == center ;

  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) ;
}


#ifdef NDEBUG
# define assert_uppercase(STR)
#else // NDEBUG
# define assert_uppercase(STR)                  \
  ({std::string str_up((STR)) ;                 \
    PosUtil::to_upper(str_up) ;                 \
    assert(str_up == (STR)) ;                   \
  })
#endif // NDEBUG



#endif // _OWLPS_POSITIONING_POSUTIL_HH_