/*
 * Copyright (c) 2009 CTTC
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation;
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Author: Nicola Baldo <nbaldo@cttc.es>
 */

#ifndef MULTI_MODEL_SPECTRUM_CHANNEL_H
#define MULTI_MODEL_SPECTRUM_CHANNEL_H

#include "spectrum-channel.h"
#include "spectrum-converter.h"
#include "spectrum-propagation-loss-model.h"
#include "spectrum-value.h"

#include <ns3/propagation-delay-model.h>

#include <map>
#include <set>

namespace ns3
{

/**
 * \ingroup spectrum
 * Container: SpectrumModelUid_t, SpectrumConverter
 */
typedef std::map<SpectrumModelUid_t, SpectrumConverter> SpectrumConverterMap_t;

/**
 * \ingroup spectrum
 * The Tx spectrum model information. This class is used to convert
 * one spectrum model into another one.
 */
class TxSpectrumModelInfo
{
  public:
    /**
     * Constructor.
     * \param txSpectrumModel the Tx Spectrum model.
     */
    TxSpectrumModelInfo(Ptr<const SpectrumModel> txSpectrumModel);

    Ptr<const SpectrumModel> m_txSpectrumModel;    //!< Tx Spectrum model.
    SpectrumConverterMap_t m_spectrumConverterMap; //!< Spectrum converter.
};

/**
 * \ingroup spectrum
 * Container: SpectrumModelUid_t, TxSpectrumModelInfo
 */
typedef std::map<SpectrumModelUid_t, TxSpectrumModelInfo> TxSpectrumModelInfoMap_t;

/**
 * \ingroup spectrum
 * The Rx spectrum model information. This class is used to convert
 * one spectrum model into another one.
 */
class RxSpectrumModelInfo
{
  public:
    /**
     * Constructor.
     * \param rxSpectrumModel the Rx Spectrum model.
     */
    RxSpectrumModelInfo(Ptr<const SpectrumModel> rxSpectrumModel);

    Ptr<const SpectrumModel> m_rxSpectrumModel; //!< Rx Spectrum model.
    std::vector<Ptr<SpectrumPhy>> m_rxPhys;     //!< Container of the Rx Spectrum phy objects.
};

/**
 * \ingroup spectrum
 * Container: SpectrumModelUid_t, RxSpectrumModelInfo
 */
typedef std::map<SpectrumModelUid_t, RxSpectrumModelInfo> RxSpectrumModelInfoMap_t;

/**
 * \ingroup spectrum
 *
 * This SpectrumChannel implementation can handle the presence of
 * SpectrumPhy instances which can use
 * different spectrum models, i.e.,  different SpectrumModel.
 *
 * \note It is allowed for a receiving SpectrumPhy to switch to a
 * different SpectrumModel during the simulation. The requirement
 * for this to work is that, after the SpectrumPhy switched its
 * SpectrumModel,  MultiModelSpectrumChannel::AddRx () is
 * called again passing the pointer to that SpectrumPhy.
 */
class MultiModelSpectrumChannel : public SpectrumChannel
{
  public:
    MultiModelSpectrumChannel();

    /**
     * \brief Get the type ID.
     * \return the object TypeId
     */
    static TypeId GetTypeId();

    // inherited from SpectrumChannel
    void RemoveRx(Ptr<SpectrumPhy> phy) override;
    void AddRx(Ptr<SpectrumPhy> phy) override;
    void StartTx(Ptr<SpectrumSignalParameters> params) override;

    // inherited from Channel
    std::size_t GetNDevices() const override;
    Ptr<NetDevice> GetDevice(std::size_t i) const override;

  protected:
    void DoDispose() override;

  private:
    /**
     * This method checks if m_rxSpectrumModelInfoMap contains an entry
     * for the given TX SpectrumModel. If such entry exists, it returns
     * an iterator pointing to it. If not, it creates a new entry in
     * m_txSpectrumModelInfoMap, and returns an iterator to it.
     *
     * \param txSpectrumModel The TX SpectrumModel  being considered
     *
     * \return An iterator pointing to the corresponding entry in m_txSpectrumModelInfoMap
     */
    TxSpectrumModelInfoMap_t::const_iterator FindAndEventuallyAddTxSpectrumModel(
        Ptr<const SpectrumModel> txSpectrumModel);

    /**
     * Used internally to reschedule transmission after the propagation delay.
     *
     * \param params The signal parameters.
     * \param receiver A pointer to the receiver SpectrumPhy.
     */
    virtual void StartRx(Ptr<SpectrumSignalParameters> params, Ptr<SpectrumPhy> receiver);

    /**
     * Data structure holding, for each TX SpectrumModel,  all the
     * converters to any RX SpectrumModel, and all the corresponding
     * SpectrumPhy instances.
     *
     */
    TxSpectrumModelInfoMap_t m_txSpectrumModelInfoMap;

    /**
     * Data structure holding, for each RX spectrum model, all the
     * corresponding SpectrumPhy instances.
     */
    RxSpectrumModelInfoMap_t m_rxSpectrumModelInfoMap;

    /**
     * Number of devices connected to the channel.
     */
    std::size_t m_numDevices;
};

} // namespace ns3

#endif /* MULTI_MODEL_SPECTRUM_CHANNEL_H */
