/*
 * Copyright (c) 2013-2014,2020 - Adjacent Link LLC, Bridgewater,
 * New Jersey
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in
 *   the documentation and/or other materials provided with the
 *   distribution.
 * * Neither the name of Adjacent Link LLC nor the names of its
 *   contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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 */

#ifndef EMANEFREESPACEPROPAGATIONMODELALGORITHM_HEADER_
#define EMANEFREESPACEPROPAGATIONMODELALGORITHM_HEADER_

#include "propagationmodelalgorithm.h"

namespace EMANE
{
  class FreeSpacePropagationModelAlgorithm : public PropagationModelAlgorithm
  {
  public:
    FreeSpacePropagationModelAlgorithm(NEMId){}

    std::pair<std::vector<double>, bool> operator()(NEMId,
                                                    const LocationInfo & locationInfo,
                                                    const FrequencySegments & segments) override
    {
      const double FSPL_CONST{41.916900439033640};

      // at least one location is unknown
      if(!locationInfo.isValid())
        {
          return {{},false};
        }

      std::vector<double> pathloss(segments.size(),0);

      double dDistance{locationInfo.getDistanceMeters()};

      if(dDistance)
        {
          size_t i {};

          for(const auto & segment : segments)
            {
              auto val =
                20.0 * log10(FSPL_CONST * (segment.getFrequencyHz() / 1000000.0) * (dDistance / 1000.0));

              pathloss[i++] = val < 0 ? 0 : val;
            }
        }

      return {pathloss,true};
    }
  };
}

#endif  // EMANEFREESPACEPROPAGATIONMODELALGORITHM_HEADER_
