/*
 * Copyright (c) 2012-2018 Centre Tecnologic de Telecomunicacions de Catalunya (CTTC)
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 * Authors:
 *   Nicola Baldo <nbaldo@cttc.es>
 *   Manuel Requena <manuel.requena@cttc.es>
 */

#ifndef RADIO_BEARER_STATS_CONNECTOR_H
#define RADIO_BEARER_STATS_CONNECTOR_H

#include "ns3/config.h"
#include "ns3/ptr.h"
#include "ns3/simple-ref-count.h"
#include "ns3/traced-callback.h"

#include <map>

namespace ns3
{

class RadioBearerStatsCalculator;

/**
 * @ingroup lte
 *
 * This class is very useful when user needs to collect
 * statistics from PDCP and RLC. It automatically connects
 * RadioBearerStatsCalculator to appropriate trace sinks.
 * Usually user does not use this class. All he/she needs
 * to do is to call: LteHelper::EnablePdcpTraces() and/or
 * LteHelper::EnableRlcTraces().
 */

class RadioBearerStatsConnector
{
  public:
    /// Constructor
    RadioBearerStatsConnector();

    /**
     * Enables trace sinks for RLC layer. Usually, this function
     * is called by LteHelper::EnableRlcTraces().
     * @param rlcStats statistics calculator for RLC layer
     */
    void EnableRlcStats(Ptr<RadioBearerStatsCalculator> rlcStats);

    /**
     * Enables trace sinks for PDCP layer. Usually, this function
     * is called by LteHelper::EnablePdcpTraces().
     * @param pdcpStats statistics calculator for PDCP layer
     */
    void EnablePdcpStats(Ptr<RadioBearerStatsCalculator> pdcpStats);

    /**
     * Connects trace sinks to appropriate trace sources
     */
    void EnsureConnected();

    // trace sinks, to be used with MakeBoundCallback

    /**
     * Function hooked to NewUeContext trace source at eNB RRC,
     * which is fired upon creation of a new UE context.
     * It stores the UE manager path and connects the callback that will be called
     * when the DRB is created in the eNB.
     * @param c
     * @param context
     * @param cellid
     * @param rnti
     */
    static void NotifyNewUeContextEnb(RadioBearerStatsConnector* c,
                                      std::string context,
                                      uint16_t cellid,
                                      uint16_t rnti);

    /**
     * Function hooked to RandomAccessSuccessful trace source at UE RRC,
     * which is fired upon successful completion of the random access procedure.
     * It connects the callbacks for the SRB0 at the eNB and the UE.
     * @param c
     * @param context
     * @param imsi
     * @param cellid
     * @param rnti
     */
    static void NotifyRandomAccessSuccessfulUe(RadioBearerStatsConnector* c,
                                               std::string context,
                                               uint64_t imsi,
                                               uint16_t cellid,
                                               uint16_t rnti);

    /**
     * Function hooked to Srb1Created trace source at UE RRC,
     * which is fired when SRB1 is created, i.e. RLC and PDCP are created for one LC = 1.
     * It connects the callbacks for the DRB at the eNB.
     * @param c
     * @param context
     * @param imsi
     * @param cellid
     * @param rnti
     */
    static void CreatedSrb1Ue(RadioBearerStatsConnector* c,
                              std::string context,
                              uint64_t imsi,
                              uint16_t cellid,
                              uint16_t rnti);

    /**
     * Function hooked to DrbCreated trace source at UE manager in eNB RRC,
     * which is fired when DRB is created, i.e. RLC and PDCP are created for LC = lcid.
     * It connects the callbacks for the DRB at the eNB.
     * @param c
     * @param context
     * @param imsi
     * @param cellid
     * @param rnti
     * @param lcid
     */
    static void CreatedDrbEnb(RadioBearerStatsConnector* c,
                              std::string context,
                              uint64_t imsi,
                              uint16_t cellid,
                              uint16_t rnti,
                              uint8_t lcid);

    /**
     * Function hooked to DrbCreated trace source at UE RRC,
     * which is fired when DRB is created, i.e. RLC and PDCP are created for LC = lcid.
     * It connects the callbacks for the DRB at the UE.
     * @param c
     * @param context
     * @param imsi
     * @param cellid
     * @param rnti
     * @param lcid
     */
    static void CreatedDrbUe(RadioBearerStatsConnector* c,
                             std::string context,
                             uint64_t imsi,
                             uint16_t cellid,
                             uint16_t rnti,
                             uint8_t lcid);

    /**
     * Disconnects all trace sources at eNB to RLC and PDCP calculators.
     * Function is not implemented.
     * @param context
     * @param imsi
     * @param cellid
     * @param rnti
     */
    void DisconnectTracesEnb(std::string context, uint64_t imsi, uint16_t cellid, uint16_t rnti);

    /**
     * Disconnects all trace sources at UE to RLC and PDCP calculators.
     * Function is not implemented.
     * @param context
     * @param imsi
     * @param cellid
     * @param rnti
     */
    void DisconnectTracesUe(std::string context, uint64_t imsi, uint16_t cellid, uint16_t rnti);

  private:
    /**
     * Creates UE Manager path and stores it in m_ueManagerPathByCellIdRnti
     * @param ueManagerPath
     * @param cellId
     * @param rnti
     */
    void StoreUeManagerPath(std::string ueManagerPath, uint16_t cellId, uint16_t rnti);

    /**
     * Connects SRB0 trace sources at UE and eNB to RLC and PDCP calculators
     * @param context
     * @param imsi
     * @param cellId
     * @param rnti
     */
    void ConnectTracesSrb0(std::string context, uint64_t imsi, uint16_t cellId, uint16_t rnti);

    /**
     * Connects SRB1 trace sources at UE and eNB to RLC and PDCP calculators
     * @param context
     * @param imsi
     * @param cellId
     * @param rnti
     */
    void ConnectTracesSrb1(std::string context, uint64_t imsi, uint16_t cellId, uint16_t rnti);

    /**
     * Connects DRB trace sources at eNB to RLC and PDCP calculators
     * @param context
     * @param imsi
     * @param cellId
     * @param rnti
     * @param lcid
     */
    void ConnectTracesDrbEnb(std::string context,
                             uint64_t imsi,
                             uint16_t cellId,
                             uint16_t rnti,
                             uint8_t lcid);

    /**
     * Connects DRB trace sources at UE to RLC and PDCP calculators
     * @param context
     * @param imsi
     * @param cellId
     * @param rnti
     * @param lcid
     */
    void ConnectTracesDrbUe(std::string context,
                            uint64_t imsi,
                            uint16_t cellId,
                            uint16_t rnti,
                            uint8_t lcid);

    Ptr<RadioBearerStatsCalculator> m_rlcStats;  //!< Calculator for RLC Statistics
    Ptr<RadioBearerStatsCalculator> m_pdcpStats; //!< Calculator for PDCP Statistics

    bool m_connected; //!< true if traces are connected to sinks, initially set to false

    /**
     * Struct used as key in m_ueManagerPathByCellIdRnti map
     */
    struct CellIdRnti
    {
        uint16_t cellId; //!< Cell Id
        uint16_t rnti;   //!< RNTI
    };

    /**
     * Less than operator for CellIdRnti, because it is used as key in map
     *
     * @param a the lhs operand
     * @param b the rhs operand
     * @returns true if less than
     */
    friend bool operator<(const CellIdRnti& a, const CellIdRnti& b);

    /**
     * List UE Manager Paths by CellIdRnti
     */
    std::map<CellIdRnti, std::string> m_ueManagerPathByCellIdRnti;
};

} // namespace ns3

#endif // RADIO_BEARER_STATS_CONNECTOR_H
