/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */

/*
    Rosegarden
    A MIDI and audio sequencer and musical notation editor.
    Copyright 2000-2022 the Rosegarden development team.
 
    Other copyrights also apply to some parts of this work.  Please
    see the AUTHORS file and individual file headers for details.
 
    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.  See the file
    COPYING included with this distribution for more information.
*/

#define RG_MODULE_STRING "[AudioPeaksThread]"

#include "AudioPeaksThread.h"
#include "AudioPeaksReadyEvent.h"

#include "base/RealTime.h"
#include "misc/Debug.h"
#include "sound/AudioFileManager.h"
#include "sound/PeakFileManager.h"
#include <QApplication>
#include <QEvent>
#include <QMutex>
#include <QObject>
#include <QThread>

#define DEBUG_AUDIO_PEAKS_THREAD 0

namespace Rosegarden
{


const QEvent::Type AudioPeaksThread::AudioPeaksQueueEmpty =
        QEvent::Type(QEvent::User + 2);

AudioPeaksThread::AudioPeaksThread(AudioFileManager *manager) :
        m_manager(manager),
        m_nextToken(0),
        m_exiting(false),
        m_emptyQueueListener(nullptr)
{}

void
AudioPeaksThread::run()
{
    bool emptyQueueSignalled = false;

#if DEBUG_AUDIO_PEAKS_THREAD
    RG_DEBUG << "run() entering";
#endif

    while (!m_exiting) {

        if (m_queue.empty()) {
            if (m_emptyQueueListener && !emptyQueueSignalled) {
                QApplication::postEvent(m_emptyQueueListener,
                                        new QEvent(AudioPeaksQueueEmpty));
                emptyQueueSignalled = true;
            }

            usleep(300000);
        } else {
            process();
        }
    }

#if DEBUG_AUDIO_PEAKS_THREAD
    RG_DEBUG << "run() exiting";
#endif
}

void
AudioPeaksThread::finish()
{
    m_exiting = true;
}

bool
AudioPeaksThread::process()
{
#if DEBUG_AUDIO_PEAKS_THREAD
    RG_DEBUG << "process()";
#endif

    // ??? There appears to be a bug that causes this to run one extra time
    //     at the beginning of a set of updates.  It's really easy to see
    //     if you enable the sleep(5) below.  The first result takes 10
    //     seconds to appear.  Then the subsequent results take 5 seconds
    //     each.  It's as if a garbage entry is always at the head of the
    //     queue.

    if (!m_queue.empty()) {

        int failed = 0;
        int inQueue = 0;
        //int count = 0;

        m_mutex.lock();

        // process 1st request and leave
        inQueue = m_queue.size();
        RequestQueue::iterator i = m_queue.begin();

        // i->first is width, which we use only to provide an ordering to
        // ensure we do smaller files first.  We don't use it here.

        RequestRec &rec = i->second;
        int token = rec.first;
        Request req = rec.second;
        m_mutex.unlock();

        // DEBUG.  Slow things down for testing.
        //sleep(5);

        std::vector<float> results;

        try {
#if DEBUG_AUDIO_PEAKS_THREAD
            RG_DEBUG << "process() file id " << req.audioFileId;
#endif

            // Requires thread-safe AudioFileManager::getPreview
            // ??? rename: getPeaks()
            results = m_manager->getPreview(req.audioFileId,
                                            req.audioStartTime,
                                            req.audioEndTime,
                                            req.width,
                                            req.showMinima);
        } catch (const AudioFileManager::BadAudioPathException &e) {

#if DEBUG_AUDIO_PEAKS_THREAD
            RG_DEBUG << "process(): failed to get peaks for audio file " << req.audioFileId << ": bad audio path: " << e.getMessage();
#endif

            // OK, we hope this just means we're still recording -- so
            // leave this one in the queue
            ++failed;

        } catch (const PeakFileManager::BadPeakFileException &e) {

#if DEBUG_AUDIO_PEAKS_THREAD
            RG_DEBUG << "process(): failed to get peaks for audio file " << req.audioFileId << ": bad peak file: " << e.getMessage();
#endif

            // As above
            ++failed;
        }

        m_mutex.lock();

        // We need to check that the token is still in the queue
        // (i.e. hasn't been cancelled).  Otherwise we shouldn't notify

        bool found = false;
        for (RequestQueue::iterator i = m_queue.begin(); i != m_queue.end(); ++i) {
            if (i->second.first == token) {
                found = true;
                m_queue.erase(i);
                break;
            }
        }

        if (found) {
            AudioFile *audioFile = m_manager->getAudioFile(req.audioFileId);
            // If there's an audio file to work with
            if (audioFile != nullptr) {
                unsigned int channels = audioFile->getChannels();
                m_results[token] = ResultsPair(channels, results);
                QObject *notify = req.notify;
                QApplication::postEvent(notify, new AudioPeaksReadyEvent(token));
            }
        }

        m_mutex.unlock();

        if (failed > 0 && failed == inQueue) {
#if DEBUG_AUDIO_PEAKS_THREAD
            RG_DEBUG << "process() - return true";
#endif

            return true; // delay and try again
        }
    }

#if DEBUG_AUDIO_PEAKS_THREAD
    RG_DEBUG << "process() - return false";
#endif

    return false;
}

int
AudioPeaksThread::requestPeaks(const Request &request)
{
    m_mutex.lock();

#if DEBUG_AUDIO_PEAKS_THREAD
    RG_DEBUG << "requestPeaks() for file id " << request.audioFileId << ", start " << request.audioStartTime << ", end " << request.audioEndTime << ", width " << request.width << ", notify " << request.notify;
#endif 
    /*!!!
        for (RequestQueue::iterator i = m_queue.begin(); i != m_queue.end(); ++i) {
    	if (i->second.second.notify == request.notify) {
    	    m_queue.erase(i);
    	    break;
    	}
        }
    */
    int token = m_nextToken;
    m_queue.insert(RequestQueue::value_type(request.width,
                                            RequestRec(token, request)));
    ++m_nextToken;
    m_mutex.unlock();

    //     if (!running()) start();

#if DEBUG_AUDIO_PEAKS_THREAD
    RG_DEBUG << "requestPeaks() - token = " << token;
#endif

    return token;
}

void
AudioPeaksThread::cancelPeaks(int token)
{
    m_mutex.lock();

#if DEBUG_AUDIO_PEAKS_THREAD
    RG_DEBUG << "cancelPeaks() for token " << token;
#endif

    for (RequestQueue::iterator i = m_queue.begin(); i != m_queue.end(); ++i) {
        if (i->second.first == token) {
            m_queue.erase(i);
            break;
        }
    }

    m_mutex.unlock();
}

void
AudioPeaksThread::getPeaks(int token, unsigned int &channels,
                               std::vector<float> &values)
{
    m_mutex.lock();

    values.clear();
    if (m_results.find(token) == m_results.end()) {
        channels = 0;
        m_mutex.unlock();
        return ;
    }

    channels = m_results[token].first;
    values = m_results[token].second;
    m_results.erase(m_results.find(token));

    m_mutex.unlock();

    return ;
}


}
