/*
 * 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.
 *
 ***********************************************************************
 */


#include "trilaterationalgorithm.hh"
#include "minmax.hh"
#include "mobile.hh"
#include "configuration.hh"
#include "posexcept.hh"

using namespace std ;
using std::tr1::unordered_map ;



/* *** Constructors *** */


TrilaterationAlgorithm::TrilaterationAlgorithm():
  request(NULL)
{
  // Will be changed when other trilateration methods will be
  // implemented.

  if (! Configuration::is_configured("positioning.area-start") ||
      ! Configuration::is_configured("positioning.area-stop"))
    throw missing_configuration(
      "You want to use MinMax, but either positioning.area-start or"
      " positioning.area-stop is not defined!") ;

  Point3D minmax_start(
    Configuration::string_value("positioning.area-start")) ;
  Point3D minmax_stop(
    Configuration::string_value("positioning.area-stop")) ;

  trilateration_method = new MinMax(minmax_start, minmax_stop) ;
}


TrilaterationAlgorithm::~TrilaterationAlgorithm()
{
  delete trilateration_method ;
}



/* *** Operations *** */


double TrilaterationAlgorithm::
make_constant_term(const Measurement &measurement)
{
  assert(request) ;
  const Mobile *mobile = request->get_mobile() ;
  assert(mobile) ;
  const AccessPoint *ap = measurement.get_ap() ;
  assert(ap) ;

  return
    ap->friis_constant_term() +
    mobile->get_antenna_gain() +
    mobile->get_trx_power() ;
}


Result TrilaterationAlgorithm::compute(const Request &_request)
{
  request = &_request ;

  compute_ap_distance_circles() ;
  Point3D position(trilaterate()) ;

  return Result(request, name, position) ;
}


void TrilaterationAlgorithm::compute_ap_distance_circles()
{
  ap_distances.clear() ;

  const unordered_map<string, Measurement> &measurements =
    request->get_measurements() ;

  for (unordered_map<string, Measurement>::const_iterator i =
         measurements.begin() ; i != measurements.end() ; ++i)
    ap_distances[i->second.get_ap()] = estimate_distance(i->second) ;
}