/*
 * Copyright (c) 2009 CTTC
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 * Author: Nicola Baldo <nbaldo@cttc.es>
 */

#include "half-duplex-ideal-phy.h"

#include "half-duplex-ideal-phy-signal-parameters.h"
#include "spectrum-error-model.h"

#include "ns3/antenna-model.h"
#include "ns3/callback.h"
#include "ns3/log.h"
#include "ns3/object-factory.h"
#include "ns3/packet-burst.h"
#include "ns3/simulator.h"
#include "ns3/trace-source-accessor.h"

#include <cmath>

namespace ns3
{

NS_LOG_COMPONENT_DEFINE("HalfDuplexIdealPhy");

NS_OBJECT_ENSURE_REGISTERED(HalfDuplexIdealPhy);

HalfDuplexIdealPhy::HalfDuplexIdealPhy()
    : m_mobility(nullptr),
      m_netDevice(nullptr),
      m_channel(nullptr),
      m_txPsd(nullptr),
      m_state(IDLE)
{
    m_interference.SetErrorModel(CreateObject<ShannonSpectrumErrorModel>());
}

HalfDuplexIdealPhy::~HalfDuplexIdealPhy()
{
}

void
HalfDuplexIdealPhy::DoDispose()
{
    NS_LOG_FUNCTION(this);
    m_mobility = nullptr;
    m_netDevice = nullptr;
    m_channel = nullptr;
    m_txPsd = nullptr;
    m_rxPsd = nullptr;
    m_txPacket = nullptr;
    m_rxPacket = nullptr;
    m_phyMacTxEndCallback = MakeNullCallback<void, Ptr<const Packet>>();
    m_phyMacRxStartCallback = MakeNullCallback<void>();
    m_phyMacRxEndErrorCallback = MakeNullCallback<void>();
    m_phyMacRxEndOkCallback = MakeNullCallback<void, Ptr<Packet>>();
    SpectrumPhy::DoDispose();
}

/**
 * @brief Output stream operator
 * @param os output stream
 * @param s the state to print
 * @return an output stream
 */
std::ostream&
operator<<(std::ostream& os, HalfDuplexIdealPhy::State s)
{
    switch (s)
    {
    case HalfDuplexIdealPhy::IDLE:
        os << "IDLE";
        break;
    case HalfDuplexIdealPhy::RX:
        os << "RX";
        break;
    case HalfDuplexIdealPhy::TX:
        os << "TX";
        break;
    default:
        os << "UNKNOWN";
        break;
    }
    return os;
}

TypeId
HalfDuplexIdealPhy::GetTypeId()
{
    static TypeId tid =
        TypeId("ns3::HalfDuplexIdealPhy")
            .SetParent<SpectrumPhy>()
            .SetGroupName("Spectrum")
            .AddConstructor<HalfDuplexIdealPhy>()
            .AddAttribute(
                "Rate",
                "The PHY rate used by this device",
                DataRateValue(DataRate("1Mbps")),
                MakeDataRateAccessor(&HalfDuplexIdealPhy::SetRate, &HalfDuplexIdealPhy::GetRate),
                MakeDataRateChecker())
            .AddTraceSource("TxStart",
                            "Trace fired when a new transmission is started",
                            MakeTraceSourceAccessor(&HalfDuplexIdealPhy::m_phyTxStartTrace),
                            "ns3::Packet::TracedCallback")
            .AddTraceSource("TxEnd",
                            "Trace fired when a previously started transmission is finished",
                            MakeTraceSourceAccessor(&HalfDuplexIdealPhy::m_phyTxEndTrace),
                            "ns3::Packet::TracedCallback")
            .AddTraceSource("RxStart",
                            "Trace fired when the start of a signal is detected",
                            MakeTraceSourceAccessor(&HalfDuplexIdealPhy::m_phyRxStartTrace),
                            "ns3::Packet::TracedCallback")
            .AddTraceSource("RxAbort",
                            "Trace fired when a previously started RX is aborted before time",
                            MakeTraceSourceAccessor(&HalfDuplexIdealPhy::m_phyRxAbortTrace),
                            "ns3::Packet::TracedCallback")
            .AddTraceSource("RxEndOk",
                            "Trace fired when a previously started RX terminates successfully",
                            MakeTraceSourceAccessor(&HalfDuplexIdealPhy::m_phyRxEndOkTrace),
                            "ns3::Packet::TracedCallback")
            .AddTraceSource("RxEndError",
                            "Trace fired when a previously started RX terminates with an error "
                            "(packet is corrupted)",
                            MakeTraceSourceAccessor(&HalfDuplexIdealPhy::m_phyRxEndErrorTrace),
                            "ns3::Packet::TracedCallback");
    return tid;
}

Ptr<NetDevice>
HalfDuplexIdealPhy::GetDevice() const
{
    NS_LOG_FUNCTION(this);
    return m_netDevice;
}

Ptr<MobilityModel>
HalfDuplexIdealPhy::GetMobility() const
{
    NS_LOG_FUNCTION(this);
    return m_mobility;
}

void
HalfDuplexIdealPhy::SetDevice(Ptr<NetDevice> d)
{
    NS_LOG_FUNCTION(this << d);
    m_netDevice = d;
}

void
HalfDuplexIdealPhy::SetMobility(Ptr<MobilityModel> m)
{
    NS_LOG_FUNCTION(this << m);
    m_mobility = m;
}

void
HalfDuplexIdealPhy::SetChannel(Ptr<SpectrumChannel> c)
{
    NS_LOG_FUNCTION(this << c);
    m_channel = c;
}

Ptr<const SpectrumModel>
HalfDuplexIdealPhy::GetRxSpectrumModel() const
{
    if (m_txPsd)
    {
        return m_txPsd->GetSpectrumModel();
    }
    else
    {
        return nullptr;
    }
}

void
HalfDuplexIdealPhy::SetTxPowerSpectralDensity(Ptr<SpectrumValue> txPsd)
{
    NS_LOG_FUNCTION(this << txPsd);
    NS_ASSERT(txPsd);
    m_txPsd = txPsd;
    NS_LOG_INFO(*txPsd << *m_txPsd);
}

void
HalfDuplexIdealPhy::SetNoisePowerSpectralDensity(Ptr<const SpectrumValue> noisePsd)
{
    NS_LOG_FUNCTION(this << noisePsd);
    NS_ASSERT(noisePsd);
    m_interference.SetNoisePowerSpectralDensity(noisePsd);
}

void
HalfDuplexIdealPhy::SetRate(DataRate rate)
{
    NS_LOG_FUNCTION(this << rate);
    m_rate = rate;
}

DataRate
HalfDuplexIdealPhy::GetRate() const
{
    NS_LOG_FUNCTION(this);
    return m_rate;
}

void
HalfDuplexIdealPhy::SetGenericPhyTxEndCallback(GenericPhyTxEndCallback c)
{
    NS_LOG_FUNCTION(this);
    m_phyMacTxEndCallback = c;
}

void
HalfDuplexIdealPhy::SetGenericPhyRxStartCallback(GenericPhyRxStartCallback c)
{
    NS_LOG_FUNCTION(this);
    m_phyMacRxStartCallback = c;
}

void
HalfDuplexIdealPhy::SetGenericPhyRxEndErrorCallback(GenericPhyRxEndErrorCallback c)
{
    NS_LOG_FUNCTION(this);
    m_phyMacRxEndErrorCallback = c;
}

void
HalfDuplexIdealPhy::SetGenericPhyRxEndOkCallback(GenericPhyRxEndOkCallback c)
{
    NS_LOG_FUNCTION(this);
    m_phyMacRxEndOkCallback = c;
}

Ptr<Object>
HalfDuplexIdealPhy::GetAntenna() const
{
    NS_LOG_FUNCTION(this);
    return m_antenna;
}

void
HalfDuplexIdealPhy::SetAntenna(Ptr<AntennaModel> a)
{
    NS_LOG_FUNCTION(this << a);
    m_antenna = a;
}

void
HalfDuplexIdealPhy::ChangeState(State newState)
{
    NS_LOG_LOGIC(this << " state: " << m_state << " -> " << newState);
    m_state = newState;
}

bool
HalfDuplexIdealPhy::StartTx(Ptr<Packet> p)
{
    NS_LOG_FUNCTION(this << p);
    NS_LOG_LOGIC(this << "state: " << m_state);

    m_phyTxStartTrace(p);

    switch (m_state)
    {
    case RX:
        AbortRx();
        // fall through

    case IDLE: {
        m_txPacket = p;
        ChangeState(TX);
        Ptr<HalfDuplexIdealPhySignalParameters> txParams =
            Create<HalfDuplexIdealPhySignalParameters>();
        Time txTimeSeconds = m_rate.CalculateBytesTxTime(p->GetSize());
        txParams->duration = txTimeSeconds;
        txParams->txPhy = GetObject<SpectrumPhy>();
        txParams->txAntenna = m_antenna;
        txParams->psd = m_txPsd;
        txParams->data = m_txPacket;

        NS_LOG_LOGIC(this << " tx power: " << 10 * std::log10(Integral(*(txParams->psd))) + 30
                          << " dBm");
        m_channel->StartTx(txParams);
        Simulator::Schedule(txTimeSeconds, &HalfDuplexIdealPhy::EndTx, this);
    }
    break;

    case TX:
        return true;
    }
    return false;
}

void
HalfDuplexIdealPhy::EndTx()
{
    NS_LOG_FUNCTION(this);
    NS_LOG_LOGIC(this << " state: " << m_state);

    NS_ASSERT(m_state == TX);

    m_phyTxEndTrace(m_txPacket);

    if (!m_phyMacTxEndCallback.IsNull())
    {
        m_phyMacTxEndCallback(m_txPacket);
    }

    m_txPacket = nullptr;
    ChangeState(IDLE);
}

void
HalfDuplexIdealPhy::StartRx(Ptr<SpectrumSignalParameters> spectrumParams)
{
    NS_LOG_FUNCTION(this << spectrumParams);
    NS_LOG_LOGIC(this << " state: " << m_state);
    NS_LOG_LOGIC(this << " rx power: " << 10 * std::log10(Integral(*(spectrumParams->psd))) + 30
                      << " dBm");

    // interference will happen regardless of the state of the receiver
    m_interference.AddSignal(spectrumParams->psd, spectrumParams->duration);

    // the device might start RX only if the signal is of a type understood by this device
    // this corresponds in real devices to preamble detection
    Ptr<HalfDuplexIdealPhySignalParameters> rxParams =
        DynamicCast<HalfDuplexIdealPhySignalParameters>(spectrumParams);
    if (rxParams)
    {
        // signal is of known type
        switch (m_state)
        {
        case TX:
            // the PHY will not notice this incoming signal

        case RX:
            // we should check if we should re-sync on a new incoming signal and discard the old one
            // (somebody calls this the "capture" effect)
            // criteria considered to do might include the following:
            //  1) signal strength (e.g., as returned by rxPsd.Norm ())
            //  2) how much time has passed since previous RX attempt started
            // if re-sync (capture) is done, then we should call AbortRx ()
            break;

        case IDLE:
            // preamble detection and synchronization is supposed to be always successful.

            Ptr<Packet> p = rxParams->data;
            m_phyRxStartTrace(p);
            m_rxPacket = p;
            m_rxPsd = rxParams->psd;
            ChangeState(RX);
            if (!m_phyMacRxStartCallback.IsNull())
            {
                NS_LOG_LOGIC(this << " calling m_phyMacRxStartCallback");
                m_phyMacRxStartCallback();
            }
            else
            {
                NS_LOG_LOGIC(this << " m_phyMacRxStartCallback is NULL");
            }
            m_interference.StartRx(p, rxParams->psd);
            NS_LOG_LOGIC(this << " scheduling EndRx with delay " << rxParams->duration);
            m_endRxEventId =
                Simulator::Schedule(rxParams->duration, &HalfDuplexIdealPhy::EndRx, this);

            break;
        }
    }
    else // rxParams == 0
    {
        NS_LOG_LOGIC(this << " signal of unknown type");
    }

    NS_LOG_LOGIC(this << " state: " << m_state);
}

void
HalfDuplexIdealPhy::AbortRx()
{
    NS_LOG_FUNCTION(this);
    NS_LOG_LOGIC(this << "state: " << m_state);

    NS_ASSERT(m_state == RX);
    m_interference.AbortRx();
    m_phyRxAbortTrace(m_rxPacket);
    m_endRxEventId.Cancel();
    m_rxPacket = nullptr;
    ChangeState(IDLE);
}

void
HalfDuplexIdealPhy::EndRx()
{
    NS_LOG_FUNCTION(this);
    NS_LOG_LOGIC(this << " state: " << m_state);

    NS_ASSERT(m_state == RX);

    bool rxOk = m_interference.EndRx();

    if (rxOk)
    {
        m_phyRxEndOkTrace(m_rxPacket);
        if (!m_phyMacRxEndOkCallback.IsNull())
        {
            NS_LOG_LOGIC(this << " calling m_phyMacRxEndOkCallback");
            m_phyMacRxEndOkCallback(m_rxPacket);
        }
        else
        {
            NS_LOG_LOGIC(this << " m_phyMacRxEndOkCallback is NULL");
        }
    }
    else
    {
        m_phyRxEndErrorTrace(m_rxPacket);
        if (!m_phyMacRxEndErrorCallback.IsNull())
        {
            NS_LOG_LOGIC(this << " calling m_phyMacRxEndErrorCallback");
            m_phyMacRxEndErrorCallback();
        }
        else
        {
            NS_LOG_LOGIC(this << " m_phyMacRxEndErrorCallback is NULL");
        }
    }

    ChangeState(IDLE);
    m_rxPacket = nullptr;
    m_rxPsd = nullptr;
}

} // namespace ns3
