/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2007-2009 Strasbourg University
 *
 * 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: Sebastien Vincent <vincent@clarinet.u-strasbg.fr>
 */

#ifndef NDISC_CACHE_H
#define NDISC_CACHE_H

#include <stdint.h>

#include <list>

#include "ns3/packet.h"
#include "ns3/nstime.h"
#include "ns3/net-device.h"
#include "ns3/ipv6-address.h"
#include "ns3/ptr.h"
#include "ns3/timer.h"
#include "ns3/sgi-hashmap.h"

namespace ns3
{

class NetDevice;
class Ipv6Interface;

/**
 * \class NdiscCache
 * \brief IPv6 Neighbor Discovery cache.
 */
class NdiscCache : public Object
{
  public:
    class Entry;

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

    /**
     * \brief Default value for unres qlen.
     */
    static const uint32_t DEFAULT_UNRES_QLEN = 3;

    /**
     * \brief Constructor.
     */
    NdiscCache ();

    /**
     * \brief Destructor.
     */
    ~NdiscCache ();

    /**
     * \brief Get the NetDevice associated with this cache.
     * \return NetDevice
     */
    Ptr<NetDevice> GetDevice () const;

    /**
     * \brief Get the Ipv6Interface associated with this cache.
     */
    Ptr<Ipv6Interface> GetInterface () const;

    /**
     * \brief Lookup in the cache.
     * \param dst destination address
     * \return the entry if found, 0 otherwise
     */
    NdiscCache::Entry* Lookup (Ipv6Address dst);

    /**
     * \brief Add an entry.
     * \param to address to add
     * \return an new Entry
     */
    NdiscCache::Entry* Add (Ipv6Address to);

    /**
     * \brief Delete an entry.
     * \param entry pointer to delete from the list.
     */
    void Remove (NdiscCache::Entry* entry);

    /**
     * \brief Flush the cache.
     */
    void Flush ();

    /**
     * \brief Set the max number of waiting packet.
     * \param unresQlen value to set
     */
    void SetUnresQlen (uint32_t unresQlen);

    /**
     * \brief Get the max number of waiting packet.
     * \return max number
     */
    uint32_t GetUnresQlen ();

    /**
     * \brief Set the device and interface.
     * \param device the device
     * \param interface the IPv6 interface
     */
    void SetDevice (Ptr<NetDevice> device, Ptr<Ipv6Interface> interface);

    /**
     * \class Entry
     * \brief A record that holds information about an NdiscCache entry.
     */
    class Entry
    {
      public:
        /**
         * \brief Constructor.
         * \param nd The NdiscCache this entry belongs to.
         */
        Entry (NdiscCache* nd);

        /**
         * \brief Changes the state to this entry to INCOMPLETE.
         * \param p packet that wait to be sent
         */
        void MarkIncomplete (Ptr<Packet> p);

        /**
         * \brief Changes the state to this entry to REACHABLE.
         * \param mac MAC address
         * \return the list of packet waiting
         */
        std::list<Ptr<Packet> > MarkReachable (Address mac);

        /**
         * \brief Changes the state to this entry to PROBE.
         */
        void MarkProbe ();

        /**
         * \brief Changes the state to this entry to STALE.
         * \param mac L2 address
         * \return the list of packet waiting
         */
        std::list<Ptr<Packet> > MarkStale (Address mac);

        /**
         * \brief Changes the state to this entry to STALE.
         */
        void MarkStale ();

        /**
         * \brief Changes the state to this entry to REACHABLE.
         */
        void MarkReachable ();

        /**
         * \brief Change the state to this entry to DELAY.
         */
        void MarkDelay ();

        /**
         * \brief Add a packet (or replace old value) in the queue.
         * \param p packet to add
         */
        void AddWaitingPacket (Ptr<Packet> p);

        /**
         * \brief Clear the waiting packet list.
         */
        void ClearWaitingPacket ();

        /**
         * \brief Is the entry STALE
         * \return true if the entry is in STALE state, false otherwise
         */
        bool IsStale () const;

        /**
         * \brief Is the entry REACHABLE
         * \return true if the entry is in REACHABLE state, false otherwise
         */
        bool IsReachable () const;

        /**
         * \brief Is the entry DELAY
         * \return true if the entry is in DELAY state, false otherwise
         */
        bool IsDelay () const;

        /**
         * \brief Is the entry INCOMPLETE
         * \return true if the entry is in INCOMPLETE state, false otherwise
         */
        bool IsIncomplete () const;

        /**
         * \brief Is the entry PROBE
         * \return true if the entry is in PROBE state, false otherwise
         */
        bool IsProbe () const;

        /**
         * \brief Get the MAC address of this entry.
         * \return the L2 address
         */
        Address GetMacAddress () const;

        /**
         * \brief Set the MAC address of this entry.
         * \param mac the MAC address to set
         */
        void SetMacAddress (Address mac);

        /**
         * \brief If the entry is a host or a router.
         * \return true if the node is a router, 0 if it is a host
         */
        bool IsRouter () const;

        /**
         * \brief Set the node type.
         * \param router true is a router, false means a host
         */
        void SetRouter (bool router);

        /**
         * \brief Get the number of NS retransmit.
         * \return number of NS that have been retransmit
         */
        uint8_t GetNSRetransmit () const;

        /**
         * \brief Increment NS retransmit.
         */
        void IncNSRetransmit ();

        /**
         * \brief Reset NS retransmit (=0).
         */
        void ResetNSRetransmit ();

        /**
         * \brief Get the time of last reachability confirmation.
         * \return time
         */
        Time GetLastReachabilityConfirmation () const;

        /**
         * \brief Update the time of last reachability confirmation.
         */
        void UpdateLastReachabilityconfirmation ();

        /**
         * \brief Start the reachable timer.
         */
        void StartReachableTimer ();

        /**
         * \brief Stop the reachable timer.
         */
        void StopReachableTimer ();

        /**
         * \brief Start retransmit timer.
         */
        void StartRetransmitTimer ();

        /**
         * \brief Stop retransmit timer.
         */
        void StopRetransmitTimer ();

        /**
         * \brief Start probe timer.
         */
        void StartProbeTimer ();

        /**
         * \brief Stop probe timer.
         */
        void StopProbeTimer ();

        /**
         * \brief Start delay timer.
         */
        void StartDelayTimer ();

        /**
         * \brief Stop delay timer.
         */
        void StopDelayTimer ();

        /**
         * \brief Function called when reachable timer timeout.
         */
        void FunctionReachableTimeout ();

        /**
         * \brief Function called when retransmit timer timeout.
         * It verify that the NS retransmit has reached the max so discard the entry
         * otherwise it retransmit a NS.
         */
        void FunctionRetransmitTimeout ();

        /**
         * \brief Function called when probe timer timeout.
         */
        void FunctionProbeTimeout ();

        /**
         * \brief Function called when delay timer timeout.
         */
        void FunctionDelayTimeout ();

        /**
         * \brief Set the IPv6 address.
         * \param ipv6Address IPv6 address
         */
        void SetIpv6Address (Ipv6Address ipv6Address);

      private:
        /**
         * \brief The IPv6 address.
         */
        Ipv6Address m_ipv6Address;

        /**
         * \brief The Entry state enumeration.
         */
        enum NdiscCacheEntryState_e
        {
          INCOMPLETE, /**< No mapping between IPv6 and L2 addresses */
          REACHABLE, /**< Mapping exists between IPv6 and L2 addresses */
          STALE, /**< Mapping is stale */
          DELAY, /**< Try to wait contact from remote host */
          PROBE /**< Try to contact IPv6 address to know again its L2 address */
        };

        /**
         * \brief The state of the entry.
         */
        NdiscCacheEntryState_e m_state;

        /**
         * \brief the NdiscCache associated.
         */
        NdiscCache* m_ndCache;

        /**
         * \brief The MAC address.
         */
        Address m_macAddress;

        /**
         * \brief The list of packet waiting.
         */
        std::list<Ptr<Packet> > m_waiting;

        /**
         * \brief Type of node (router or host).
         */
        bool m_router;

        /**
         * \brief Reachable timer (used for NUD in REACHABLE state).
         */
        Timer m_reachableTimer;

        /**
         * \brief Retransmission timer (used for NUD in INCOMPLETE state).
         */
        Timer m_retransTimer;

        /**
         * \brief Probe timer (used for NUD in PROBE state).
         */
        Timer m_probeTimer;

        /**
         * \brief Delay timer (used for NUD when in DELAY state).
         */
        Timer m_delayTimer;

        /**
         * \brief Last time we see a reachability confirmation.
         */
        Time m_lastReachabilityConfirmation;

        /**
         * \brief Number of NS retransmission.
         */
        uint8_t m_nsRetransmit;
    };

  private:
    typedef sgi::hash_map<Ipv6Address, NdiscCache::Entry *, Ipv6AddressHash> Cache;
    typedef sgi::hash_map<Ipv6Address, NdiscCache::Entry *, Ipv6AddressHash>::iterator CacheI;

    /**
     * \brief Copy constructor.
     * \param a cache to copy
     */
    NdiscCache (NdiscCache const &a);
    
    /**
     * \brief Equal operator.
     * \param a cache to copy
     */
    NdiscCache& operator= (NdiscCache const &a);

    /**
     * \brief Dispose this object.
     */
    void DoDispose ();

    /**
     * \brief The NetDevice.
     */
    Ptr<NetDevice> m_device;

    /**
     * \brief the interface.
     */
    Ptr<Ipv6Interface> m_interface;

    /**
     * A list of Entry.
     */
    Cache m_ndCache;

    /**
     * \brief Max number of packet stored in m_waiting.
     */
    uint32_t m_unresQlen;
};

} /* namespace ns3 */

#endif /* NDISC_CACHE_H */