// Boost pinger (c) 2011 by Guilherme Maciel Ferreira / Intra2net AG
// Based upon work copyright (c) 2003-2010 Christopher M. Kohlhoff (ping.cpp)
// Modified 2014 by Christian Herdtweck, Intra2net AG
//
// Distributed under the Boost Software License, Version 1.0.
//    (See accompanying file LICENSE_1_0.txt or copy at
//          http://www.boost.org/LICENSE_1_0.txt)
#ifndef ICMP_PINGER_H
#define ICMP_PINGER_H

#include <stdint.h>

#include <string>
#include <set>

#include <boost/asio.hpp>
#include <boost/function.hpp>
#include <boost/shared_ptr.hpp>

#include "host/pinger.h"
#include "host/pingstatus.h"
#include "icmp/icmppacket.h"


using boost::asio::ip::icmp;

class IcmpPinger;
typedef boost::shared_ptr<IcmpPinger> IcmpPingerItem;

class IcmpPacketDistributor;
typedef boost::shared_ptr<IcmpPacketDistributor> IcmpPacketDistributorItem;

typedef boost::shared_ptr<icmp::socket> SocketItem;

//-----------------------------------------------------------------------------
// IcmpPacketDistributor
//-----------------------------------------------------------------------------


class IcmpPacketDistributor
{
public:
    bool register_pinger( const IcmpPingerItem &new_pinger );
    bool unregister_pinger( const IcmpPingerItem &old_pinger );

    SocketItem get_socket() const;

    static IcmpPacketDistributorItem get_distributor(
            const icmp::socket::protocol_type &protocol,
            const std::string &network_interface,
            const IoServiceItem io_serv
    );

    static IcmpPacketDistributorItem get_distributor(
            const icmp::socket::protocol_type &protocol,
            const std::string &network_interface
    );

    static void clean_up_all();

    ~IcmpPacketDistributor();

private:
    // hide away constructor, copy constructor and assignment operator
    IcmpPacketDistributor(
            const icmp::socket::protocol_type &protocol,
            const std::string &network_interface,
            const IoServiceItem io_serv
    );
    IcmpPacketDistributor(IcmpPacketDistributor const&);
    void operator=(IcmpPacketDistributor const&);

    void register_receive_handler();
    void handle_receive( const boost::system::error_code &error,
                         const size_t &bytes_transferred );
    void clean_up();

private:
    /// Network layer protocol used to ping, IPv4 or IPv6
    icmp::socket::protocol_type Protocol;

    /// The socket object
    SocketItem Socket;

    /// The buffer where the data received will be placed
    boost::asio::streambuf ReplyBuffer;

    std::set<IcmpPingerItem> PingerList;

    // for each IP protocol (v4/v6) and each network interface (string),
    //   there can only be one IcmpPacketDistributor instance
    typedef std::pair<icmp::socket::protocol_type, std::string>
                                                 DistributorInstanceIdentifier;

    struct InstanceIdentifierComparator
    {
        bool operator() ( const DistributorInstanceIdentifier &a,
                          const DistributorInstanceIdentifier &b ) const ;
    };

    typedef std::map<DistributorInstanceIdentifier, IcmpPacketDistributorItem,
                     InstanceIdentifierComparator> map_type;
    /// Instances, one for each (protocol, interface) - pair
    static map_type Instances;
};

//-----------------------------------------------------------------------------
// IcmpPinger
//-----------------------------------------------------------------------------

/**
 * @brief This class performs an ICMP ping to host using Boost Asio.
 * Scope: one object per host.
 */
class IcmpPinger : public Pinger
{
public:
    static PingerItem create(
            const IoServiceItem io_serv,
            const boost::asio::ip::icmp::socket::protocol_type &protocol,
            const std::string &source_network_interface,
            const int echo_reply_timeout_in_sec
    );

    virtual ~IcmpPinger();

    virtual void ping(
            const boost::asio::ip::address &destination_ip,
            const uint16_t destination_port,
            boost::function<void(PingStatus,long)> ping_done_callback
    );

    virtual void stop_pinging();

    bool handle_receive_icmp_packet(const IcmpPacketItem icmp_packet,
                                    const size_t bytes_transferred
    );

private:
    IcmpPinger(
            const IoServiceItem io_serv,
            const boost::asio::ip::icmp::socket::protocol_type &protocol,
            const int echo_reply_timeout_in_sec,
            const IcmpPacketDistributorItem distributor
    );

    void set_destination_endpoint(const boost::asio::ip::address &destination);

    bool start_send();
    bool send_echo_request( const IcmpPacketItem icmp_packet );
    void schedule_timeout_echo_reply();
    void handle_timeout(const boost::system::error_code &error);

    void set_ping_status( PingStatus ping_status );

private:
    IcmpPacketDistributorItem PacketDistributor;

    /// The destination host
    boost::asio::ip::icmp::endpoint DestinationEndpoint;
    /// Network layer protocol used to ping, IPv4 or IPv6
    boost::asio::ip::icmp::socket::protocol_type Protocol;
    /// The timer of ICMP packet receive, triggers the timeout to avoid infinite
    /// wait
    boost::asio::deadline_timer IcmpPacketReceiveTimer;
    /// ICMP packet identifier
    uint16_t Identifier;
    /// ICMP packet sequence_number
    uint16_t SequenceNumber;
    /// The time when the last ICMP packet was sent
    boost::posix_time::ptime TimeSent;
    /// Flag to indicate if we got a reply or not
    bool ReplyReceived;
    /// The amount of time to wait for the reply
    int EchoReplyTimeoutInSec;
    /// The status of the pinger
    PingStatus PingerStatus;
    /// Callback to notify when the ping is done (got reply/timeout)
    boost::function< void(PingStatus,long) > PingDoneCallback;
    /// prefix to logging output lines
    std::string LogPrefix;
};

#endif // ICMP_PINGER_H