/********************************************************************************
 *    Copyright (C) 2014 GSI Helmholtzzentrum fuer Schwerionenforschung GmbH    *
 *                                                                              *
 *              This software is distributed under the terms of the             *
 *         GNU Lesser General Public Licence version 3 (LGPL) version 3,        *
 *                  copied verbatim in the file "LICENSE"                       *
 ********************************************************************************/

#include "FairMQShmMonitor.h"
#include "FairMQShmCommon.h"

#include <boost/interprocess/managed_shared_memory.hpp>
#include <boost/interprocess/containers/vector.hpp>
#include <boost/interprocess/containers/string.hpp>
#include <boost/interprocess/allocators/allocator.hpp>

#include <boost/interprocess/sync/named_mutex.hpp>
#include <boost/interprocess/ipc/message_queue.hpp>
#include <boost/date_time/posix_time/posix_time.hpp>

#include <csignal>
#include <iostream>
#include <iomanip>

#include <termios.h>
#include <poll.h>

using namespace std;
namespace bipc = boost::interprocess;
namespace bpt = boost::posix_time;

using CharAllocator   = bipc::allocator<char, bipc::managed_shared_memory::segment_manager>;
using String          = bipc::basic_string<char, std::char_traits<char>, CharAllocator>;
using StringAllocator = bipc::allocator<String, bipc::managed_shared_memory::segment_manager>;
using StringVector    = bipc::vector<String, StringAllocator>;

namespace
{
    volatile std::sig_atomic_t gSignalStatus;
}

namespace fair
{
namespace mq
{
namespace shmem
{

void signalHandler(int signal)
{
    gSignalStatus = signal;
}

Monitor::Monitor(const string& segmentName, bool selfDestruct, bool interactive, unsigned int timeoutInMS)
    : fSelfDestruct(selfDestruct)
    , fInteractive(interactive)
    , fSeenOnce(false)
    , fTimeoutInMS(timeoutInMS)
    , fSegmentName(segmentName)
    , fTerminating(false)
    , fHeartbeatTriggered(false)
    , fLastHeartbeat()
    , fSignalThread()
    , fManagementSegment(bipc::open_or_create, "fairmq_shmem_management", 65536)
{
    MonitorStatus* monitorStatus = fManagementSegment.find<MonitorStatus>(bipc::unique_instance).first;
    if (monitorStatus != nullptr)
    {
        cout << "shmmonitor already started or not properly exited. Try `shmmonitor --cleanup`" << endl;
        exit(EXIT_FAILURE);
    }
    fManagementSegment.construct<MonitorStatus>(bipc::unique_instance)();

    CleanupControlQueues();
}

void Monitor::CatchSignals()
{
    signal(SIGINT, signalHandler);
    signal(SIGTERM, signalHandler);
    fSignalThread = thread(&Monitor::SignalMonitor, this);
}

void Monitor::SignalMonitor()
{
    while (true)
    {
        if (gSignalStatus != 0)
        {
            fTerminating = true;
            cout << "signal: " << gSignalStatus << endl;
            break;
        }
        else if (fTerminating)
        {
            break;
        }

        this_thread::sleep_for(chrono::milliseconds(100));
    }
}

void Monitor::Run()
{
    thread heartbeatThread(&Monitor::MonitorHeartbeats, this);

    if (fInteractive)
    {
        Interactive();
    }
    else
    {
        while (!fTerminating)
        {
            this_thread::sleep_for(chrono::milliseconds(100));
            CheckSegment();
        }
    }

    heartbeatThread.join();
}

void Monitor::MonitorHeartbeats()
{
    try
    {
        bipc::message_queue mq(bipc::open_or_create, "fairmq_shmem_control_queue", 1000, sizeof(bool));

        unsigned int priority;
        bipc::message_queue::size_type recvdSize;

        while (!fTerminating)
        {
            bool heartbeat;
            bpt::ptime rcvTill = bpt::microsec_clock::universal_time() + bpt::milliseconds(100);
            if (mq.timed_receive(&heartbeat, sizeof(heartbeat), recvdSize, priority, rcvTill))
            {
                fHeartbeatTriggered = true;
                fLastHeartbeat = chrono::high_resolution_clock::now();
            }
            else
            {
                // cout << "control queue timeout" << endl;
            }
        }
    }
    catch (bipc::interprocess_exception& ie)
    {
        cout << ie.what() << endl;
    }

    CleanupControlQueues();
}

void Monitor::Interactive()
{
    char c;
    pollfd cinfd[1];
    cinfd[0].fd = fileno(stdin);
    cinfd[0].events = POLLIN;

    struct termios t;
    tcgetattr(STDIN_FILENO, &t); // get the current terminal I/O structure
    t.c_lflag &= ~ICANON; // disable canonical input
    tcsetattr(STDIN_FILENO, TCSANOW, &t); // apply the new settings

    cout << endl;
    PrintHelp();
    cout << endl;
    PrintHeader();

    while (!fTerminating)
    {
        if (poll(cinfd, 1, 100))
        {
            if (fTerminating || gSignalStatus != 0)
            {
                break;
            }

            c = getchar();

            switch (c)
            {
                case 'q':
                    cout << "[q] --> quitting." << endl;
                    fTerminating = true;
                    break;
                case 'p':
                    cout << "[p] --> active queues:" << endl;
                    PrintQueues();
                    break;
                case 'x':
                    cout << "[x] --> closing shared memory:" << endl;
                    Cleanup(fSegmentName);
                    break;
                case 'h':
                    cout << "[h] --> help:" << endl << endl;
                    PrintHelp();
                    cout << endl;
                    break;
                case '\n':
                    cout << "[\\n] --> invalid input." << endl;
                    break;
                default:
                    cout << "[" << c << "] --> invalid input." << endl;
                    break;
            }

            if (fTerminating)
            {
                break;
            }

            PrintHeader();
        }

        if (fTerminating)
        {
            break;
        }

        CheckSegment();

        if (!fTerminating)
        {
            cout << "\r";
        }
    }

    tcgetattr(STDIN_FILENO, &t); // get the current terminal I/O structure
    t.c_lflag |= ICANON; // re-enable canonical input
    tcsetattr(STDIN_FILENO, TCSANOW, &t); // apply the new settings
}

void Monitor::CheckSegment()
{
    static uint64_t counter = 0;
    char c = '#';

    if (fInteractive)
    {
        int mod = counter++ % 5;
        switch (mod)
        {
            case 0:
                c = '-';
                break;
            case 1:
                c = '\\';
                break;
            case 2:
                c = '|';
                break;
            case 3:
                c = '-';
                break;
            case 4:
                c = '/';
                break;
            default:
                break;
        }
    }

    try
    {
        bipc::managed_shared_memory segment(bipc::open_only, fSegmentName.c_str());

        fSeenOnce = true;

        unsigned int numDevices = 0;

        fair::mq::shmem::DeviceCounter* dc = segment.find<fair::mq::shmem::DeviceCounter>(bipc::unique_instance).first;
        if (dc)
        {
            numDevices = dc->fCount;
        }

        auto now = chrono::high_resolution_clock::now();
        unsigned int duration = chrono::duration_cast<chrono::milliseconds>(now - fLastHeartbeat).count();

        if (fHeartbeatTriggered && duration > fTimeoutInMS)
        {
            cout << "no heartbeats since over " << fTimeoutInMS << " milliseconds, cleaning..." << endl;
            Cleanup(fSegmentName);
            fHeartbeatTriggered = false;
            if (fSelfDestruct)
            {
                cout << "self destructing" << endl;
                fTerminating = true;
            }
        }

        if (fInteractive)
        {
            cout << "| "
                << setw(18) << fSegmentName << " | "
                << setw(10) << segment.get_size() << " | "
                << setw(10) << segment.get_free_memory() << " | "
                // << setw(15) << segment.all_memory_deallocated() << " | "
                << setw(2) << segment.check_sanity() << " | "
                // << setw(10) << segment.get_num_named_objects() << " | "
                << setw(10) << numDevices << " | "
                // << setw(10) << segment.get_num_unique_objects() << " |"
                << setw(10) << duration << " |"
                << c
                << flush;
        }
    }
    catch (bipc::interprocess_exception& ie)
    {
        fHeartbeatTriggered = false;
        if (fInteractive)
        {
            cout << "| "
                << setw(18) << "-" << " | "
                << setw(10) << "-" << " | "
                << setw(10) << "-" << " | "
                // << setw(15) << "-" << " | "
                << setw(2) << "-" << " | "
                << setw(10) << "-" << " | "
                << setw(10) << "-" << " |"
                << c
                << flush;
        }
        if (fSelfDestruct)
        {
            if (fSeenOnce)
            {
                cout << "self destructing" << endl;
                fTerminating = true;
            }
        }
    }
}

void Monitor::Cleanup(const string& segmentName)
{
    try
    {
        bipc::managed_shared_memory managementSegment(bipc::open_only, "fairmq_shmem_management");
        RegionCounter* rc = managementSegment.find<RegionCounter>(bipc::unique_instance).first;
        if (rc)
        {
            cout << "Region counter found: " << rc->fCount << endl;
            unsigned int regionCount = rc->fCount;
            for (int i = 1; i <= regionCount; ++i)
            {
                RemoveObject("fairmq_shmem_region_" + to_string(regionCount));
            }
        }
        else
        {
            cout << "shmem: no region counter found. no regions to cleanup." << endl;
        }

        RemoveObject("fairmq_shmem_management");
    }
    catch (bipc::interprocess_exception& ie)
    {
        cout << "Did not find \"fairmq_shmem_management\" shared memory segment. No regions to cleanup." << endl;
    }

    RemoveObject(segmentName);

    boost::interprocess::named_mutex::remove("fairmq_shmem_mutex");
}

void Monitor::RemoveObject(const std::string& name)
{
    if (bipc::shared_memory_object::remove(name.c_str()))
    {
        cout << "Successfully removed \"" << name << "\" shared memory segment." << endl;
    }
    else
    {
        cout << "Did not remove \"" << name << "\" shared memory segment. Already removed?" << endl;
    }
}

void Monitor::CleanupControlQueues()
{
    if (bipc::message_queue::remove("fairmq_shmem_control_queue"))
    {
        // cout << "successfully removed control queue" << endl;
    }
    else
    {
        // cout << "could not remove control queue" << endl;
    }
}

void Monitor::PrintQueues()
{
    cout << '\n';

    try
    {
        bipc::managed_shared_memory segment(bipc::open_only, fSegmentName.c_str());
        StringVector* queues = segment.find<StringVector>("fairmq_shmem_queues").first;
        if (queues)
        {
            cout << "found " << queues->size() << " queue(s):" << endl;

            for (int i = 0; i < queues->size(); ++i)
            {
                string name(queues->at(i).c_str());
                cout << '\t' << name << " : ";
                atomic<int>* queueSize = segment.find<atomic<int>>(name.c_str()).first;
                if (queueSize)
                {
                    cout << *queueSize << " messages" << endl;
                }
                else
                {
                    cout << "\tqueue does not have a queue size entry." << endl;
                }
            }
        }
        else
        {
            cout << "\tno queues found" << endl;
        }
    }
    catch (bipc::interprocess_exception& ie)
    {
        cout << "\tno queues found" << endl;
    }
    catch (std::out_of_range& ie)
    {
        cout << "\tno queues found" << endl;
    }

    cout << endl;
}

void Monitor::PrintHeader()
{
    cout << "| "
        << "\033[01;32m" << setw(18) << "name"            << "\033[0m" << " | "
        << "\033[01;32m" << setw(10) << "size"            << "\033[0m" << " | "
        << "\033[01;32m" << setw(10) << "free"            << "\033[0m" << " | "
        // << "\033[01;32m" << setw(15) << "all deallocated" << "\033[0m" << " | "
        << "\033[01;32m" << setw(2)  << "ok"              << "\033[0m" << " | "
        // << "\033[01;32m" << setw(10) << "# named"         << "\033[0m" << " | "
        << "\033[01;32m" << setw(10) << "# devices"       << "\033[0m" << " | "
        // << "\033[01;32m" << setw(10) << "# unique"        << "\033[0m" << " |"
        << "\033[01;32m" << setw(10) << "ms since"        << "\033[0m" << " |"
        << endl;
}

void Monitor::PrintHelp()
{
    cout << "controls: [x] close memory, [p] print queues, [h] help, [q] quit." << endl;
}

Monitor::~Monitor()
{
    fManagementSegment.destroy<MonitorStatus>(bipc::unique_instance);
    if (fSignalThread.joinable())
    {
        fSignalThread.join();
    }
}

} // namespace shmem
} // namespace mq
} // namespace fair