/*************************************************************************\
* Copyright (c) 2015 UChicago Argonne LLC, as Operator of Argonne
*     National Laboratory.
* Copyright (c) 2002 The Regents of the University of California, as
*     Operator of Los Alamos National Laboratory.
* SPDX-License-Identifier: EPICS
* EPICS BASE is distributed subject to a Software License Agreement found
* in file LICENSE that is included with this distribution.
\*************************************************************************/
/*
 *      Author  Jeffrey O. Hill
 *              johill@lanl.gov
 *              505 665 1831
 */

#include <stdio.h>

#include "epicsAtomic.h"
#include "timerPrivate.h"
#include "errlog.h"

#ifdef _MSC_VER
#   pragma warning ( push )
#   pragma warning ( disable:4660 )
#endif

template class epicsSingleton < timerQueueActiveMgr >;

#ifdef _MSC_VER
#   pragma warning ( pop )
#endif

epicsSingleton < timerQueueActiveMgr > timerQueueMgrEPICS;

epicsTimerQueueActive::~epicsTimerQueueActive () {}

epicsTimerQueueActive & epicsTimerQueueActive::allocate ( bool okToShare, unsigned threadPriority )
{
    epicsSingleton < timerQueueActiveMgr >::reference pMgr =
        timerQueueMgrEPICS.getReference ();
    return pMgr->allocate ( pMgr, okToShare, threadPriority );
}

timerQueueActive ::
    timerQueueActive ( RefMgr & refMgr,
        bool okToShareIn, unsigned priority ) :
    _refMgr ( refMgr ), queue ( *this ), thread ( *this, "timerQueue",
        epicsThreadGetStackSize ( epicsThreadStackMedium ), priority ),
    sleepQuantum ( epicsThreadSleepQuantum() ), okToShare ( okToShareIn ),
    exitFlag ( 0 ), terminateFlag ( false )
{
}

void timerQueueActive::start ()
{
    this->thread.start ();
}

timerQueueActive::~timerQueueActive ()
{
    this->terminateFlag = true;
    this->rescheduleEvent.signal ();
    while ( !  epics::atomic::get(this->exitFlag) ) {
        this->exitEvent.wait ( 1.0 );
    }
    // in case other threads are waiting here also
    this->exitEvent.signal ();
}

void timerQueueActive :: _printLastChanceExceptionMessage (
    const char * pExceptionTypeName,
    const char * pExceptionContext )
{
    char date[64];
    try {
        epicsTime cur = epicsTime :: getCurrent ();
        cur.strftime ( date, sizeof ( date ), "%a %b %d %Y %H:%M:%S.%f");
    }
    catch ( ... ) {
        strcpy ( date, "<UKN DATE>" );
    }
    errlogPrintf (
        "timerQueueActive: Unexpected C++ exception \"%s\" with type \"%s\" "
        "while processing timer queue, at %s\n",
        pExceptionContext, pExceptionTypeName, date );
}


void timerQueueActive :: run ()
{
    epics::atomic::set(this->exitFlag, 0);
    while ( ! this->terminateFlag ) {
        try {
            double delay = this->queue.process ( epicsTime::getCurrent() );
            debugPrintf ( ( "timer thread sleeping for %g sec (max)\n", delay ) );
            this->rescheduleEvent.wait ( delay );
        }
        catch ( std :: exception & except ) {
            _printLastChanceExceptionMessage (
                typeid ( except ).name (), except.what () );
            epicsThreadSleep ( 10.0 );
        }
        catch ( ... ) {
            _printLastChanceExceptionMessage (
                "catch ( ... )", "Non-standard C++ exception" );
            epicsThreadSleep ( 10.0 );
        }
    }
    epics::atomic::set(this->exitFlag, 1);
    this->exitEvent.signal (); // no access to queue after exitEvent signal
}

epicsTimer & timerQueueActive::createTimer ()
{
    return this->queue.createTimer();
}

epicsTimerForC & timerQueueActive::createTimerForC ( epicsTimerCallback pCallback, void * pArg )
{
    return this->queue.createTimerForC ( pCallback, pArg );
}

void timerQueueActive::reschedule ()
{
    this->rescheduleEvent.signal ();
}

double timerQueueActive::quantum ()
{
    return this->sleepQuantum;
}

void timerQueueActive::show ( unsigned int level ) const
{
    printf ( "EPICS threaded timer queue at %p\n",
        static_cast <const void *> ( this ) );
    if ( level > 0u ) {
        // specifying level one here avoids recursive
        // show callback
        this->thread.show ( 1u );
        this->queue.show ( level - 1u );
        printf ( "reschedule event\n" );
        this->rescheduleEvent.show ( level - 1u );
        printf ( "exit event\n" );
        this->exitEvent.show ( level - 1u );
        printf ( "exitFlag = %c, terminateFlag = %c\n",
            epics::atomic::get(this->exitFlag) ? 'T' : 'F',
            this->terminateFlag ? 'T' : 'F' );
    }
}

epicsTimerQueue & timerQueueActive::getEpicsTimerQueue ()
{
    return static_cast < epicsTimerQueue &> ( * this );
}