//+==================================================================================================================
//
// file :               LockThread.cpp
//
// description :        C++ source code for the LockThread class. This class is used for the locking thread. The rule of
//                        this thread is to regulary send the device locking command to a DS admin device
//
// project :            TANGO
//
// author(s) :          E.Taurel
//
// Copyright (C) :      2004,2005,2006,2007,2008,2009,2010,2011,2012,2013,2014,2015
//                        European Synchrotron Radiation Facility
//                      BP 220, Grenoble 38043
//                      FRANCE
//
// This file is part of Tango.
//
// Tango is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Tango 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 Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License along with Tango.
// If not, see <http://www.gnu.org/licenses/>.
//
//
//-=================================================================================================================

#include <tango/tango.h>
#include <tango/client/lockthread.h>

#include <functional>
#include <algorithm>
#include <ctime>

#ifdef _TG_WINDOWS_
  #include <sys/types.h>
#endif

namespace
{

auto find_device(const std::vector<Tango::LockedDevice> &cont, const std::string &name)
{
    return std::find_if(
        std::begin(cont), std::end(cont), [&name](const Tango::LockedDevice &dev) { return dev.dev_name == name; });
}
} // namespace

namespace Tango
{

//+-------------------------------------------------------------------------------------------------------------------
//
// method :
//        LockThread::LockThread
//
// description :
//        The locking thread constructor.
//
//--------------------------------------------------------------------------------------------------------------------

LockThread::LockThread(
    LockThCmd &cmd, TangoMonitor &m, DeviceProxy *adm, const std::string &dev, LockClock::duration per) :
    shared_cmd(cmd),
    p_mon(m),
    admin_proxy(adm)
{
    LockedDevice ld;
    ld.dev_name = dev;
    ld.validity = per;
    locked_devices.push_back(ld);

    local_cmd.cmd_pending = false;

    period = per - std::chrono::microseconds(500000);
    sleep = period;
}

//+------------------------------------------------------------------------------------------------------------------
//
// method :
//        LockThread::run_undetached
//
// description :
//        The locking thread main code
//
//--------------------------------------------------------------------------------------------------------------------

void LockThread::run(TANGO_UNUSED(void *ptr))
{
    LockCmdType received;

    next_work = LockClock::now() + period;

    //
    // The infinite loop
    //

    while(true)
    {
        try
        {
            received = get_command();

            switch(received)
            {
            case LOCK_COMMAND:
                execute_cmd();
                break;

            case LOCK_TIME_OUT:
                one_more_lock();
                break;
            }

            compute_sleep_time(received == LOCK_COMMAND);
        }
        catch(omni_thread_fatal &)
        {
            std::cerr << "OUPS !! A omni thread fatal exception !!!!!!!!" << std::endl;
#ifndef _TG_WINDOWS_
            const time_t t = Tango::get_current_system_datetime();
            std::cerr << ctime(&t);
#endif
            std::cerr << "Trying to re-enter the main loop" << std::endl;
        }
    }
}

//+------------------------------------------------------------------------------------------------------------------
//
// method :
//        LockThread::get_command
//
// description :
//        This method wait on the shared monitor for a new command to be sent to the polling thread. The thread waits
//        with a timeout. If the thread is awaken due to the timeout, false is returned. If the work list is empty,
//        the thread waits for ever.
//
// returns :
//        The command type enum: Is it a real command or a time-out
//
//-------------------------------------------------------------------------------------------------------------------

LockCmdType LockThread::get_command()
{
    if(sleep.has_value() && *sleep == LockClock::duration::zero())
    {
        return LOCK_TIME_OUT;
    }

    omni_mutex_lock sync(p_mon);
    LockCmdType ret;

    //
    // Wait on monitor
    //

    if(!shared_cmd.cmd_pending)
    {
        if(locked_devices.empty())
        {
            p_mon.wait();
        }
        else
        {
            if(sleep.has_value())
            {
                p_mon.wait(std::chrono::duration_cast<std::chrono::milliseconds>(*sleep).count());
            }
        }
    }

    //
    // Test if it is a new command. If yes, copy its data locally
    //

    if(shared_cmd.cmd_pending)
    {
        local_cmd = shared_cmd;
        ret = LOCK_COMMAND;
    }
    else
    {
        ret = LOCK_TIME_OUT;
    }

    return ret;
}

//+------------------------------------------------------------------------------------------------------------------
//
// method :
//        LockThread::execute_cmd
//
// description :
//        This method is called when a command has been received. It execute the command!
//
//-------------------------------------------------------------------------------------------------------------------

void LockThread::execute_cmd()
{
    bool need_exit = false;

    switch(local_cmd.cmd_code)
    {
        //
        // Add a new device
        //

    case Tango::LOCK_ADD_DEV:
    {
        LockedDevice ld;
        ld.dev_name = local_cmd.dev_name;
        ld.validity = local_cmd.lock_validity;

        auto pos = find_device(locked_devices, local_cmd.dev_name);

        if(pos == locked_devices.end())
        {
            locked_devices.push_back(ld);
        }
        update_th_period();
        break;
    }

        //
        // Remove an already locked device
        //

    case Tango::LOCK_REM_DEV:
    {
        auto pos = find_device(locked_devices, local_cmd.dev_name);

        if(pos != locked_devices.end())
        {
            locked_devices.erase(pos);
        }

        if(!locked_devices.empty())
        {
            update_th_period();
        }
        break;
    }

        //
        // Ask locking thread to unlock all its devices and to exit
        //

    case Tango::LOCK_UNLOCK_ALL_EXIT:
        unlock_all_devs();
        need_exit = true;
        break;

        //
        // Ask locking thread to exit
        //

    case Tango::LOCK_EXIT:
        need_exit = true;
        break;
    }

    //
    // Inform requesting thread that the work is done
    //

    {
        omni_mutex_lock sync(p_mon);
        shared_cmd.cmd_pending = false;
        if(locked_devices.empty())
        {
            shared_cmd.suicide = true;
        }
        p_mon.signal();
    }

    //
    // If the command was an exit one, do it now
    //

    if(need_exit)
    {
        omni_thread::exit();
    }

    //
    // If it is the last device, ask thread to exit buut delete the proxy first
    //

    if(locked_devices.empty())
    {
        omni_thread::exit();
    }
}

//+------------------------------------------------------------------------------------------------------------------
//
// method :
//        LockThread::one_more_lock
//
// description :
//        Send ReLockDevices command to the admin device
//
//-------------------------------------------------------------------------------------------------------------------

void LockThread::one_more_lock()
{
    DeviceData d_in;
    if(re_lock_cmd_args.empty())
    {
        for(unsigned long loop = 0; loop < locked_devices.size(); ++loop)
        {
            re_lock_cmd_args.push_back(locked_devices[loop].dev_name);
        }
    }
    d_in << re_lock_cmd_args;

    try
    {
        //        TANGO_LOG << "Locking Thread: I am re-locking devices (" << re_lock_cmd_args.size() << ")" <<
        //        std::endl;
        admin_proxy->command_inout("ReLockDevices", d_in);
    }
    catch(Tango::DevFailed &e)
    {
        //        TANGO_LOG << "LockThread: Gasp, an exception while sending command to admin device" << std::endl;

        //
        // If we had a locking error, retrieve device name and remove it from the locked devices list
        //

        for(unsigned long loop = 0; loop < e.errors.length(); loop++)
        {
            if((::strcmp(e.errors[loop].reason.in(), API_DeviceLocked) == 0) ||
               (::strcmp(e.errors[loop].reason.in(), API_DeviceNotLocked) == 0) ||
               (::strcmp(e.errors[loop].reason.in(), API_DeviceNotExported) == 0))
            {
                std::string error_message(e.errors[loop].desc.in());
                std::string::size_type pos = error_message.find(':');
                if(pos != std::string::npos)
                {
                    std::string local_dev_name = error_message.substr(0, pos);
                    std::vector<LockedDevice>::iterator ite;
                    for(ite = locked_devices.begin(); ite != locked_devices.end(); ++ite)
                    {
                        if(TG_strcasecmp(local_dev_name.c_str(), ite->dev_name.c_str()) == 0)
                        {
                            locked_devices.erase(ite);
                            if(locked_devices.empty())
                            {
                                local_cmd.cmd_code = LOCK_EXIT;
                                execute_cmd();
                            }
                            break;
                        }
                    }
                }
            }
        }
    }
}

//+-------------------------------------------------------------------------------------------------------------------
//
// method :
//        LockThread::unlock_all_devs
//
// description :
//        Unlock all devices handled by this thread
//
//--------------------------------------------------------------------------------------------------------------------

void LockThread::unlock_all_devs()
{
    if(!locked_devices.empty())
    {
        DeviceData din;
        DevVarLongStringArray sent_data;
        unsigned int locked_devices_nb = locked_devices.size();
        sent_data.svalue.length(locked_devices_nb);
        for(unsigned int loop = 0; loop < locked_devices_nb; loop++)
        {
            sent_data.svalue[loop] = Tango::string_dup(locked_devices[loop].dev_name.c_str());
        }
        sent_data.lvalue.length(1);
        sent_data.lvalue[0] = 1;

        din << sent_data;

        try
        {
            admin_proxy->command_inout("UnLockDevice", din);
        }
        catch(Tango::DevFailed &)
        {
        }
    }
}

//+------------------------------------------------------------------------------------------------------------------
//
// method :
//        LockThread::update_th_period
//
// description :
//        This method manage the thread update period. The update period is the smallest lock validity of all the
//        locked device minus 0.5 sec
//
//-------------------------------------------------------------------------------------------------------------------

void LockThread::update_th_period()
{
    //
    // Clear the ReLock command args vector
    //

    re_lock_cmd_args.clear();

    //
    // Find the smallest lock validity
    //

    std::vector<LockedDevice>::iterator ite;
    ite = min_element(locked_devices.begin(), locked_devices.end());

    //
    // Compute new thread period
    //

    period = ite->validity - std::chrono::microseconds(500000);
}

//+------------------------------------------------------------------------------------------------------------------
//
// method :
//        LockThread::compute_sleep_time
//
// description :
//        This method computes how many mS the thread should sleep before the next lock time.
//
//--------------------------------------------------------------------------------------------------------------------

void LockThread::compute_sleep_time(bool cmd)
{
    if(!cmd)
    {
        sleep = period;
        next_work = PollClock::now() + period;
    }
    else
    {
        auto diff = next_work - PollClock::now();
        if(diff < PollClock::duration::zero())
        {
            sleep = std::nullopt;
        }
        else
        {
            sleep = diff;
        }
    }
}

} // namespace Tango
