/*
 * 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.
 */


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

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



/* *** Constructors *** */


MultilaterationAlgorithm::MultilaterationAlgorithm():
  request(NULL)
{
  // Will be changed when other multilateration 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")) ;

  multilateration_method = new MinMax(minmax_start, minmax_stop) ;
}


MultilaterationAlgorithm::~MultilaterationAlgorithm()
{
  delete multilateration_method ;
}



/* *** Operations *** */


double MultilaterationAlgorithm::
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 MultilaterationAlgorithm::compute(const Request &_request)
{
  request = &_request ;

  compute_ap_distance_circles() ;
  Point3D position(multilaterate()) ;

  return Result(request, name, position) ;
}


void MultilaterationAlgorithm::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) ;
}