///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2017 Edouard Griffiths, F4EXB                                   //
// Copyright (C) 2020 Jon Beniston, M7RCE                                        //
//                                                                               //
// 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 as version 3 of the License, or                  //
// (at your option) any later version.                                           //
//                                                                               //
// This program 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 General Public License V3 for more details.                               //
//                                                                               //
// You should have received a copy of the GNU General Public License             //
// along with this program. If not, see <http://www.gnu.org/licenses/>.          //
///////////////////////////////////////////////////////////////////////////////////

#include <errno.h>
#include <algorithm>

#include <QDebug>

#include "dsp/samplesourcefifo.h"

#include "usrpoutputthread.h"
#include "usrpoutputsettings.h"

USRPOutputThread::USRPOutputThread(uhd::tx_streamer::sptr stream, size_t bufSamples, SampleSourceFifo* sampleFifo, QObject* parent) :
    QThread(parent),
    m_running(false),
    m_stream(stream),
    m_bufSamples(bufSamples),
    m_sampleFifo(sampleFifo),
    m_log2Interp(0)
{
    // *2 as samples are I+Q
    m_buf = new qint16[2*bufSamples];
    std::fill(m_buf, m_buf + 2*bufSamples, 0);
}

USRPOutputThread::~USRPOutputThread()
{
    stopWork();
    delete m_buf;
}

void USRPOutputThread::startWork()
{
    if (m_running) return; // return if running already

    // Reset stats
    m_packets = 0;
    m_underflows = 0;
    m_droppedPackets = 0;

    m_startWaitMutex.lock();
    start();
    while(!m_running)
        m_startWaiter.wait(&m_startWaitMutex, 100);
    m_startWaitMutex.unlock();
}

void USRPOutputThread::stopWork()
{
    uhd::async_metadata_t md;

    if (!m_running) return; // return if not running

    m_running = false;
    wait();

    try
    {
        // Get message indicating underflow, so it doesn't appear if we restart
        m_stream->recv_async_msg(md);
    }
    catch (std::exception& e)
    {
        qDebug() << "USRPOutputThread::stopWork: exception: " << e.what();
    }

    qDebug("USRPOutputThread::stopWork: stream stopped");
}

void USRPOutputThread::setLog2Interpolation(unsigned int log2_interp)
{
    m_log2Interp = log2_interp;
}

void USRPOutputThread::run()
{
    uhd::tx_metadata_t md;
    md.start_of_burst = false;
    md.end_of_burst   = false;

    m_running = true;
    m_startWaiter.wakeAll();

    qDebug("USRPOutputThread::run");

    while (m_running)
    {
        callback(m_buf, m_bufSamples);

        try
        {
            const size_t samples_sent = m_stream->send(m_buf, m_bufSamples, md);
            m_packets++;
            if (samples_sent != m_bufSamples)
            {
                qDebug("USRPOutputThread::run written %ld/%ld samples", samples_sent, m_bufSamples);
            }
        }
        catch (std::exception& e)
        {
            qDebug() << "USRPOutputThread::run: exception: " << e.what();
        }
    }

    m_running = false;
}

//  Interpolate according to specified log2 (ex: log2=4 => decim=16)
void USRPOutputThread::callback(qint16* buf, qint32 len)
{
    SampleVector& data = m_sampleFifo->getData();
    unsigned int iPart1Begin, iPart1End, iPart2Begin, iPart2End;
    m_sampleFifo->read(len/(1<<m_log2Interp), iPart1Begin, iPart1End, iPart2Begin, iPart2End);

    if (iPart1Begin != iPart1End) {
        callbackPart(buf, data, iPart1Begin, iPart1End);
    }

    unsigned int shift = (iPart1End - iPart1Begin)*(1<<m_log2Interp);

    if (iPart2Begin != iPart2End) {
        callbackPart(buf + 2*shift, data, iPart2Begin, iPart2End);
    }
}

void USRPOutputThread::callbackPart(qint16* buf, SampleVector& data, unsigned int iBegin, unsigned int iEnd)
{
    SampleVector::iterator beginRead = data.begin() + iBegin;
    int len = 2*(iEnd - iBegin)*(1<<m_log2Interp);

    if (m_log2Interp == 0)
    {
        m_interpolators.interpolate1(&beginRead, buf, len);
    }
    else
    {
        switch (m_log2Interp)
        {
        case 1:
            m_interpolators.interpolate2_cen(&beginRead, buf, len);
            break;
        case 2:
            m_interpolators.interpolate4_cen(&beginRead, buf, len);
            break;
        case 3:
            m_interpolators.interpolate8_cen(&beginRead, buf, len);
            break;
        case 4:
            m_interpolators.interpolate16_cen(&beginRead, buf, len);
            break;
        case 5:
            m_interpolators.interpolate32_cen(&beginRead, buf, len);
            break;
        case 6:
            m_interpolators.interpolate64_cen(&beginRead, buf, len);
            break;
        default:
            break;
        }
    }
}

void USRPOutputThread::getStreamStatus(bool& active, quint32& underflows, quint32& droppedPackets)
{
    uhd::async_metadata_t md;

    if (m_stream->recv_async_msg(md))
    {
        if ((md.event_code == uhd::async_metadata_t::event_code_t::EVENT_CODE_UNDERFLOW)
            || (md.event_code == uhd::async_metadata_t::event_code_t::EVENT_CODE_UNDERFLOW_IN_PACKET))
            m_underflows++;
        if ((md.event_code == uhd::async_metadata_t::event_code_t::EVENT_CODE_SEQ_ERROR)
            || (md.event_code == uhd::async_metadata_t::event_code_t::EVENT_CODE_SEQ_ERROR_IN_BURST))
            m_droppedPackets++;
    }
    //qDebug() << "USRPOutputThread::getStreamStatus " << m_packets << " " << m_underflows << " " << m_droppedPackets;
    active = m_packets > 0;
    underflows = m_underflows;
    droppedPackets = m_droppedPackets;
}