/*
 * Copyright (c) 2005 INRIA
 *
 * 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: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
 */

#ifndef MAC_RX_MIDDLE_H
#define MAC_RX_MIDDLE_H

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

#include <map>

namespace ns3
{

class WifiMacHeader;
class OriginatorRxStatus;
class Packet;
class Mac48Address;
class WifiMpdu;

/**
 * \ingroup wifi
 *
 * This class handles duplicate detection and recomposition of fragments.
 */
class MacRxMiddle : public SimpleRefCount<MacRxMiddle>
{
  public:
    /**
     * typedef for callback
     */
    typedef Callback<void, Ptr<const WifiMpdu>, uint8_t /* link ID */> ForwardUpCallback;

    MacRxMiddle();
    ~MacRxMiddle();

    /**
     * Set a callback to forward the packet up.
     *
     * \param callback the callback to set
     */
    void SetForwardCallback(ForwardUpCallback callback);

    /**
     * Receive an MPDU on the given link.
     *
     * \param mpdu the MPDU
     * \param linkId the ID of the given link
     */
    void Receive(Ptr<const WifiMpdu> mpdu, uint8_t linkId);

  private:
    /// allow MacRxMiddleTest associated class access
    friend class MacRxMiddleTest;
    /**
     * Look up for OriginatorRxStatus associated with the sender address
     * (by looking at ADDR2 field in the header).
     * The method creates a new OriginatorRxStatus if one is not already presented.
     *
     * \param hdr the MAC header
     *
     * \return OriginatorRxStatus
     */
    OriginatorRxStatus* Lookup(const WifiMacHeader* hdr);
    /**
     * Check if we have already received the packet from the sender before
     * (by looking at the sequence control field).
     *
     * \param hdr the MAC header
     * \param originator the packet originator status
     *
     * \return true if we already received the packet previously,
     *         false otherwise
     */
    bool IsDuplicate(const WifiMacHeader* hdr, OriginatorRxStatus* originator) const;
    /**
     * Check if the received packet is a fragment and handle it appropriately.
     * If the packet is not a fragment, the method returns the packet.
     * If the packet is a fragment (not the last fragment), the method initiates
     * de-fragmentation process and return 0.
     * If the packet is the last fragment, the method tries to re-construct the full packet
     * and return the packet if success.
     *
     * \param packet the packet
     * \param hdr the MAC header
     * \param originator the packet originator status
     *
     * \return a packet if the packet is successfully reassembled (or not a fragment),
     *         0 if we failed to reassemble the packet (e.g. missing fragments/out-of-order).
     */
    Ptr<const Packet> HandleFragments(Ptr<const Packet> packet,
                                      const WifiMacHeader* hdr,
                                      OriginatorRxStatus* originator);

    /**
     * typedef for a map between address and OriginatorRxStatus
     */
    typedef std::map<Mac48Address, OriginatorRxStatus*, std::less<Mac48Address>> Originators;
    /**
     * typedef for a map between address, OriginatorRxStatus, and Traffic ID
     */
    typedef std::map<std::pair<Mac48Address, uint8_t>,
                     OriginatorRxStatus*,
                     std::less<std::pair<Mac48Address, uint8_t>>>
        QosOriginators;
    /**
     * typedef for an iterator for Originators
     */
    typedef std::map<Mac48Address, OriginatorRxStatus*, std::less<Mac48Address>>::iterator
        OriginatorsI;
    /**
     * typedef for an iterator for QosOriginators
     */
    typedef std::map<std::pair<Mac48Address, uint8_t>,
                     OriginatorRxStatus*,
                     std::less<std::pair<Mac48Address, uint8_t>>>::iterator QosOriginatorsI;

    Originators m_originatorStatus;       ///< originator status
    QosOriginators m_qosOriginatorStatus; ///< QOS originator status
    ForwardUpCallback m_callback;         ///< forward up callback
};

} // namespace ns3

#endif /* MAC_RX_MIDDLE_H */
