/*
 * "$Id: rsthreads.cc,v 1.1 2007-02-19 20:08:30 rmf24 Exp $"
 *
 * RetroShare C++ Interface.
 *
 * Copyright 2004-2007 by Robert Fernie.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License Version 2 as published by the Free Software Foundation.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA.
 *
 * Please report all bugs and problems to "retroshare@lunamutt.com".
 *
 */


#include "rsthreads.h"
#include <unistd.h>    // for usleep()
#include <errno.h>    // for errno
#include <iostream>
#include <time.h>

#ifdef RSMUTEX_DEBUG
#include <stdio.h>
#include <sys/time.h>
#endif

/*******
 * #define DEBUG_THREADS 1
 * #define RSMUTEX_ABORT 1  // Catch wrong pthreads mode.
 *******/
#define THREAD_DEBUG std::cerr << "[this=" << (void*)this << ", caller thread ID: " << std::hex << pthread_self() << ", thread ID: " << mTid << std::dec << "] "

#ifdef RSMUTEX_ABORT
	#include <stdlib.h>
#endif

#ifdef DEBUG_THREADS
	#include <iostream>
#endif

void *RsThread::rsthread_init(void* p)
{
  RsThread *thread = (RsThread *) p;
  if (!thread)
  {
    return NULL;
  }
    // tell the OS to free the thread resources when this function exits
    // it is a replacement for pthread_join()
    pthread_detach(pthread_self());

#ifdef DEBUG_THREADS
    std::cerr << "[Thread ID:" << std::hex << pthread_self() << std::dec << "] thread is started. Calling runloop()..." << std::endl;
#endif
    
  thread -> runloop();
  return NULL;
}
RsThread::RsThread() 
{
#ifdef WINDOWS_SYS
    memset (&mTid, 0, sizeof(mTid));
#else
    mTid = 0;
#endif
    // The thread is certainly not running. This avoids to lock down when calling shutdown on a thread that has never started.

#ifdef DEBUG_THREADS
    THREAD_DEBUG << "[Thread ID:" << std::hex << pthread_self() << std::dec << "] thread object created. Initing stopped=1, should_stop=0" << std::endl;
#endif
    mHasStoppedSemaphore.set(1) ;
    mShouldStopSemaphore.set(0) ;
}

bool RsThread::isRunning()
{
    // do we need a mutex for this ?
    int sval = mHasStoppedSemaphore.value() ;

    return !sval ;
}

bool RsThread::shouldStop()
{
        int sval = mShouldStopSemaphore.value() ;
        return sval > 0;
}

void RsTickingThread::shutdown()
{
#ifdef DEBUG_THREADS
    THREAD_DEBUG << "pqithreadstreamer::shutdown()" << std::endl;
#endif

    int sval = mHasStoppedSemaphore.value() ;

    if(sval > 0)
    {
#ifdef DEBUG_THREADS
        THREAD_DEBUG << "  thread not running. Quit." << std::endl;
#endif
        return ;
    }

    ask_for_stop() ;
}

void RsThread::ask_for_stop()
{
#ifdef DEBUG_THREADS
    THREAD_DEBUG << "  calling stop" << std::endl;
#endif
    mShouldStopSemaphore.set(1);
}

void RsTickingThread::fullstop()
{
    shutdown() ;

#ifdef DEBUG_THREADS
    THREAD_DEBUG << "  waiting stop" << std::endl;
#endif
    if(pthread_equal(mTid,pthread_self()))
    {
        THREAD_DEBUG << "(WW) RsTickingThread::fullstop() called by same thread. This is unexpected." << std::endl;
        return ;
    }
    
    mHasStoppedSemaphore.wait_no_relock(); // Wait for semaphore value to become 1, but does not decrement it when obtained.
#ifdef DEBUG_THREADS
    THREAD_DEBUG << "  finished!" << std::endl;
#endif
}

void RsThread::start(const std::string &threadName)
{
    pthread_t tid;
    void  *data = (void *)this ;

#ifdef DEBUG_THREADS
    THREAD_DEBUG << "pqithreadstreamer::start() initing should_stop=0" << std::endl;
#endif
    mShouldStopSemaphore.set(0) ;

    int err ;

    // pthread_create is a memory barrier
    // -> the new thread will see mIsRunning() = true

    if( 0 == (err=pthread_create(&tid, 0, &rsthread_init, data)))
    {
        mTid = tid;

        // set name
#ifdef __USE_GNU
        if(!threadName.empty()) {
            // thread names are restricted to 16 characters including the terminating null byte
            if(threadName.length() > 15)
            {
#ifdef DEBUG_THREADS
                THREAD_DEBUG << "RsThread::start called with to long name '" << name << "' truncating..." << std::endl;
#endif
                pthread_setname_np(mTid, threadName.substr(0, 15).c_str());
            } else {
                pthread_setname_np(mTid, threadName.c_str());
            }
        }
#endif
    }
    else
    {
        THREAD_DEBUG << "Fatal error: pthread_create could not create a thread. Error returned: " << err << " !!!!!!!" << std::endl;
        mHasStoppedSemaphore.set(1) ;
    }
}



RsTickingThread::RsTickingThread()
{
#ifdef DEBUG_THREADS
    THREAD_DEBUG << "RsTickingThread::RsTickingThread()" << std::endl;
#endif
}

void RsSingleJobThread::runloop()
{
    mHasStoppedSemaphore.set(0) ;
    run() ;
}

void RsTickingThread::runloop()
{
    mHasStoppedSemaphore.set(0) ;	// first time we are 100% the thread is actually running.

#ifdef DEBUG_THREADS
    THREAD_DEBUG << "RsTickingThread::runloop(). Setting stopped=0" << std::endl;
#endif

    while(1)
    {
        if(shouldStop())
        {
#ifdef DEBUG_THREADS
            THREAD_DEBUG << "pqithreadstreamer::runloop(): asked to stop. setting hasStopped=1, and returning. Thread ends." << std::endl;
#endif
            mHasStoppedSemaphore.set(1);
            return ;
        }

        data_tick();
    }
}

RsQueueThread::RsQueueThread(uint32_t min, uint32_t max, double relaxFactor )
    :mMinSleep(min), mMaxSleep(max), mRelaxFactor(relaxFactor)
{
    mLastSleep = (uint32_t)mMinSleep ;
    mLastWork = time(NULL) ;
}

void RsQueueThread::data_tick()
{
    bool doneWork = false;
    while(workQueued() && doWork())
    {
        doneWork = true;
    }
    time_t now = time(NULL);
    if (doneWork)
    {
        mLastWork = now;
        mLastSleep = (uint32_t) (mMinSleep + (mLastSleep - mMinSleep) / 2.0);
#ifdef DEBUG_TICKING
        THREAD_DEBUG << "RsQueueThread::data_tick() done work: sleeping for: " << mLastSleep << " ms" << std::endl;
#endif

    }
    else
    {
        uint32_t deltaT = now - mLastWork;
        double frac = deltaT / mRelaxFactor;

        mLastSleep += (uint32_t)
                        ((mMaxSleep-mMinSleep) * (frac + 0.05));
        if (mLastSleep > mMaxSleep)
        {
            mLastSleep = mMaxSleep;
        }
#ifdef DEBUG_TICKING
        THREAD_DEBUG << "RsQueueThread::data_tick() no work: sleeping for: " << mLastSleep << " ms" << std::endl;
#endif
    }
    usleep(mLastSleep * 1000); // mLastSleep msec
}

void RsMutex::unlock()
{ 
#ifdef RSTHREAD_SELF_LOCKING_GUARD
	if(--_cnt == 0)
	{
#endif
		_thread_id = 0 ;
		pthread_mutex_unlock(&realMutex); 

#ifdef RSTHREAD_SELF_LOCKING_GUARD
	}
#endif
}

void RsMutex::lock()
{
#ifdef RSMUTEX_DEBUG
	pthread_t owner = _thread_id ;
#endif

	int retval = 0;
#ifdef RSTHREAD_SELF_LOCKING_GUARD
	if(!trylock())
		if(!pthread_equal(_thread_id,pthread_self()))
#endif
			retval = pthread_mutex_lock(&realMutex);

	switch(retval)
	{
		case 0:
			break;

		case EINVAL:
			std::cerr << "RsMutex::lock() pthread_mutex_lock returned EINVAL";
			std::cerr << std::endl;
			break;
 
		case EBUSY:
			std::cerr << "RsMutex::lock() pthread_mutex_lock returned EBUSY";
			std::cerr << std::endl;
			break;
 
		case EAGAIN:
			std::cerr << "RsMutex::lock() pthread_mutex_lock returned EAGAIN";
			std::cerr << std::endl;
			break;
 
		case EDEADLK:
			std::cerr << "RsMutex::lock() pthread_mutex_lock returned EDEADLK";
			std::cerr << std::endl;
			break;
 
		case EPERM:
			std::cerr << "RsMutex::lock() pthread_mutex_lock returned EPERM";
			std::cerr << std::endl;
			break;

		default:
			std::cerr << "RsMutex::lock() pthread_mutex_lock returned UNKNOWN ERROR";
			std::cerr << std::endl;
			break;
	}

	/* Here is some debugging code - to catch failed locking attempts.
	 * Major bug is it is ever triggered.
	 */
#ifdef RSMUTEX_ABORT

	if (retval != 0)
	{
#ifdef RSMUTEX_DEBUG
		std::cerr << "RsMutex::lock() name: " << name << std::endl;
#endif
		std::cerr << "RsMutex::lock() pthread_mutex_lock returned an Error. Aborting()";
		std::cerr << std::endl;
		abort();
	}
#endif

 
	_thread_id = pthread_self() ;
#ifdef RSTHREAD_SELF_LOCKING_GUARD
	++_cnt ;
#endif
}
#ifdef RSMUTEX_DEBUG
double RsStackMutex::getCurrentTS()
{

#ifndef WINDOWS_SYS
        struct timeval cts_tmp;
        gettimeofday(&cts_tmp, NULL);
        double cts =  (cts_tmp.tv_sec) + ((double) cts_tmp.tv_usec) / 1000000.0;
#else
        struct _timeb timebuf;
        _ftime( &timebuf);
        double cts =  (timebuf.time) + ((double) timebuf.millitm) / 1000.0;
#endif
        return cts;
}
#endif