// Cyphesis Online RPG Server and AI Engine
// Copyright (C) 2000,2001 Alistair Riddoch
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
// 
// 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA


#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

/*
 * Imported MetaServer API implementation.
 */
#include "metaserverapi/MetaServerAPI.hpp"

#include "CommMetaClient.h"

#include "common/debug.h"
#include "common/log.h"
#include "common/globals.h"
#include "common/Monitors.h"
#include "common/compose.hpp"
#include <varconf/config.h>

#include <cstring>
#include <iostream>
#include <memory>
#include <vector>
#include <boost/algorithm/string.hpp>


using namespace boost::asio;
static const bool debug_flag = false;


/// \brief Constructor for metaserver communication socket object.
///
/// @param svr Reference to the object that manages all socket communication.
CommMetaClient::CommMetaClient(io_service& ioService) :
        mSocket(ioService, ip::udp::endpoint(ip::udp::v4(), 0)), mKeepaliveTimer(
                ioService), mResolver(ioService), mHasEndpoint(false), m_heartbeatTime(300)
{
}

CommMetaClient::~CommMetaClient()
{
}

/// \brief Set the target address if the communication socket.
///
/// @param mserver String address of the metaserver,
int CommMetaClient::setup(const std::string & mserver)
{
    m_server = mserver;

    /*
     * Ensure attributes list is clear
     */
    m_serverAttributes.clear();

    /*
     * Get the heartbeat time
     */
    readConfigItem("cyphesis","msheartbeat", m_heartbeatTime);

    /*
     * Update the attributes to include config + monitors
     */
    updateAttributes();

    ip::udp::resolver::query query(ip::udp::v4(), m_server, "8453");
    mResolver.async_resolve(query,
            [this](boost::system::error_code ec, ip::udp::resolver::iterator iterator ) {
                if (!ec) {
                    mHasEndpoint = true;
                    mDestination = *iterator;
                    this->metaserverKeepalive();
                    this->do_receive();
                    this->keepalive();
                }
            });

    return 0;
}

void CommMetaClient::do_receive()
{
    mSocket.async_receive_from(buffer(mReadBuffer.data(), MAX_PACKET_BYTES), mDestination,
            [this](boost::system::error_code ec, std::size_t length)
            {
                if (!ec)
                {
                    this->metaserverReply(length);
                }
                this->do_receive();
            });
}

void CommMetaClient::keepalive()
{

    mKeepaliveTimer.expires_from_now(
            boost::posix_time::seconds(m_heartbeatTime));

    mKeepaliveTimer.async_wait([this](boost::system::error_code ec)
    {
        if (!ec)
        {
            ip::udp::resolver::query query(ip::udp::v4(), m_server, "8453");
            mResolver.async_resolve(query,
                    [this](boost::system::error_code ec, ip::udp::resolver::iterator iterator ) {
                        if (!ec) {
                            mDestination = *iterator;
                            mHasEndpoint = true;
                            this->metaserverKeepalive();
                        }
                    });
        }
        this->keepalive();
    });
}

/// \brief Send a keepalive packet to the metaserver.
///
/// This should be called periodically to send a packet notifying the
/// metaserver that this server is still alive.
void CommMetaClient::metaserverKeepalive()
{

	auto keep = std::make_shared<MetaServerPacket>();

    keep->setPacketType(NMT_SERVERKEEPALIVE);

    mSocket.async_send_to(buffer(keep->getBuffer().data(), keep->getSize()),
            mDestination,
            [this, keep](boost::system::error_code ec, std::size_t length)
            {
                if (!ec)
                {
                    updateAttributes();
                    sendAllAttributes();
                }
            });
}

/// \brief Read a reply from the metaserver.
///
/// Read the data sent by the metaserver. If the packet received is
/// a handshake, respond with the required response to verify that
/// we are alive.
void CommMetaClient::metaserverReply(size_t packet_size)
{
    uint32_t handshake = 0, command = 0;

    if ( packet_size < (std::streamsize)sizeof(command)) {
        log(WARNING, "WARNING: Reply from metaserver too short");
        return;
    }

    MetaServerPacket shake(mReadBuffer, packet_size);

    if(shake.getPacketType() == NMT_HANDSHAKE )
    {
        handshake = shake.getIntData(4); // we know 4 bytes for type, and 4 for shake
        debug(std::cout << "MetaServer contacted successfully."
                        << std::endl << std::flush;);

        auto servershake = std::make_shared<MetaServerPacket>();
        servershake->setPacketType(NMT_SERVERSHAKE);
        servershake->addPacketData(handshake);


        mSocket.async_send_to(buffer(servershake->getBuffer().data(), servershake->getSize()),mDestination,
                [this, servershake](boost::system::error_code ec, std::size_t length){});


    }
}

/// \brief Send a terminate packet to the metaserver.
///
/// This should be called to indicate that this server is going down,
/// and should no longer be listed.
void CommMetaClient::metaserverTerminate()
{

    mKeepaliveTimer.cancel();
    if (mHasEndpoint) {
        try {
        auto term = std::make_shared<MetaServerPacket>();

        term->setPacketType(NMT_TERMINATE);

        //Do a blocking send as we're calling this when we're shutting down.
            mSocket.send_to(buffer(term->getBuffer().data(), term->getSize()), mDestination);
        } catch (const std::exception& e) {
            //This isn't fatal
            log(INFO, String::compose("Got error when trying to send data to the metaserver at shutdown: %1", e.what()));
        }
    }
}

void CommMetaClient::metaserverAttribute(const std::string& k, const std::string & v )
{
    auto m = std::make_shared<MetaServerPacket>();

    m->setPacketType(NMT_SERVERATTR);
    m->addPacketData(k.length());
    m->addPacketData(v.length());
    m->addPacketData(k);
    m->addPacketData(v);


    mSocket.async_send_to(buffer(m->getBuffer().data(), m->getSize()), mDestination,
            [this, m](boost::system::error_code ec, std::size_t length){});
}

/// \brief Read attributes from config and monitor
///
///
void CommMetaClient::updateAttributes()
{
    std::string mstats;
    std::vector<std::string> fields;

    /*
     * Get pipe separate list from the config about monitored variables
     */
    readConfigItem("cyphesis", "metastats", mstats);

    /*
     * Split on | character
     */
    boost::algorithm::split( fields, mstats, boost::algorithm::is_any_of( "|" ) );

    /*
     * Iterate fields and snag from the monitor, if it exists;
     */
    for (auto& v : fields)
    {
        std::stringstream ss;
        if ( Monitors::instance()->readVariable(v,ss) == 0 )
        {
            std::string tmp = ss.str();
            boost::algorithm::trim(tmp);
            m_serverAttributes[v] = tmp;
        } else {
            ss << "WARNING: [cyphesis].metastats item [" << v << "] is not a monitored variable";
            log(WARNING,ss.str());
        }
    }

    /*
     * Get the configuration values to send
     * In the event that a user has specified a variable that matches
     * the name of a monitor, the configured item will have priority.
     */
    const varconf::sec_map& c = global_conf->getSection("metaattributes");
    for (auto& kv : c)
    {
        std::string s = kv.second;
        boost::algorithm::trim(s);
        m_serverAttributes[kv.first] = s;
    }


}

/// \brief Utility to send all attributes to the metaserver
///
void CommMetaClient::sendAllAttributes()
{
    for (auto& kv : m_serverAttributes) {
        metaserverAttribute(kv.first, kv.second);
    }
}