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#include <QDebug>

#include <QVBoxLayout>

#include <QAudioOutput>

#include <QAudioDeviceInfo>

#include "audiooutput.h"

#ifndef M_PI

#define M_PI 3.14159265358979323846

#endif

#define SECONDS     1

#define FREQ        600

#define SYSTEM_FREQ 44100

Generator::Generator(QObject *parent)

    :QIODevice( parent )

{

    finished = false;

    buffer = new char[SECONDS*SYSTEM_FREQ*4+1000];

    t=buffer;

    len=fillData(t,FREQ,SECONDS); /* mono FREQHz sine */

    pos   = 0;

    total = len;

}

Generator::~Generator()

{

    delete [] buffer;

}

void Generator::start()

{

    open(QIODevice::ReadOnly);

}

void Generator::stop()

{

    close();

}

int Generator::putShort(char *t, unsigned int value)

{

    *(unsigned char *)(t++)=value&255;

    *(unsigned char *)(t)=(value/256)&255;

    return 2;

}

int Generator::fillData(char *start, int frequency, int seconds)

{

    int i, len=0;

    int value;

    for(i=0; i<seconds*SYSTEM_FREQ; i++) {

        value=(int)(32767.0*sin(2.0*M_PI*((double)(i))*(double)(frequency)/SYSTEM_FREQ));

        putShort(start, value);

        start += 4;

        len+=2;

    }

    return len;

}

qint64 Generator::readData(char *data, qint64 maxlen)

{

    int len = maxlen;

    if(len > 16384)

        len = 16384;

    if(len < (SECONDS*SYSTEM_FREQ*2)-pos) {

        // Normal

        memcpy(data,t+pos,len);

        pos+=len;

        return len;

    } else {

        // Whats left and reset to start

        qint64 left = (SECONDS*SYSTEM_FREQ*2)-pos;

        memcpy(data,t+pos,left);

        pos=0;

        return left;

    }

}

qint64 Generator::writeData(const char *data, qint64 len)

{

    Q_UNUSED(data);

    Q_UNUSED(len);

    return 0;

}

AudioTest::AudioTest()

{

    QWidget *window = new QWidget;

    QVBoxLayout* layout = new QVBoxLayout;

    deviceBox = new QComboBox(this);

    foreach (const QAudioDeviceInfo &deviceInfo, QAudioDeviceInfo::deviceList(QAudio::AudioOutput))

        deviceBox->addItem(deviceInfo.deviceName(), qVariantFromValue(deviceInfo));

    connect(deviceBox,SIGNAL(activated(int)),SLOT(deviceChanged(int)));

    layout->addWidget(deviceBox);

    button = new QPushButton(this);

    button->setText(tr("Click for Push Mode"));

    connect(button,SIGNAL(clicked()),SLOT(toggle()));

    layout->addWidget(button);

    button2 = new QPushButton(this);

    button2->setText(tr("Click To Suspend"));

    connect(button2,SIGNAL(clicked()),SLOT(togglePlay()));

    layout->addWidget(button2);

    window->setLayout(layout);

    setCentralWidget(window);

    window->show();

    buffer = new char[BUFFER_SIZE];

    gen = new Generator(this);

    pullMode = true;

    timer = new QTimer(this);

    connect(timer,SIGNAL(timeout()),SLOT(writeMore()));

    gen->start();

    settings.setFrequency(SYSTEM_FREQ);

    settings.setChannels(1);

    settings.setSampleSize(16);

    settings.setCodec("audio/pcm");

    settings.setByteOrder(QAudioFormat::LittleEndian);

    settings.setSampleType(QAudioFormat::SignedInt);

    audioOutput = new QAudioOutput(settings,this);

    connect(audioOutput,SIGNAL(notify()),SLOT(status()));

    connect(audioOutput,SIGNAL(stateChanged(QAudio::State)),SLOT(state(QAudio::State)));

    audioOutput->start(gen);

}

AudioTest::~AudioTest()

{

    delete [] buffer;

}

void AudioTest::deviceChanged(int idx)

{

    timer->stop();

    gen->stop();

    audioOutput->stop();

    audioOutput->disconnect(this);

    delete audioOutput;

    device = deviceBox->itemData(idx).value<QAudioDeviceInfo>();

    audioOutput = new QAudioOutput(device,settings,this);

    connect(audioOutput,SIGNAL(notify()),SLOT(status()));

    connect(audioOutput,SIGNAL(stateChanged(QAudio::State)),SLOT(state(QAudio::State)));

    gen->start();

    audioOutput->start(gen);

}

void AudioTest::status()

{

    qWarning()<<"byteFree = "<<audioOutput->bytesFree()<<" bytes, clock = "<<audioOutput->clock()/1000<<"ms, totalTime = "<<audioOutput->totalTime()/1000<<"ms";

}

void AudioTest::writeMore()

{

    if(!audioOutput)

        return;

    if(audioOutput->state() == QAudio::StopState)

        return;

    int    l;

    int    out;

    int chunks = audioOutput->bytesFree()/audioOutput->periodSize();

    while(chunks) {

       l = gen->read(buffer,audioOutput->periodSize());

       if(l > 0)

           out = output->write(buffer,l);

       if(l != audioOutput->periodSize())

	   break;

       chunks--;

    }

}

void AudioTest::toggle()

{

    // Change between pull and push modes

    timer->stop();

    audioOutput->stop();

    if (pullMode) {

        button->setText("Click for Pull Mode");

        output = audioOutput->start(0);

        pullMode = false;

        timer->start(20);

    } else {

        button->setText("Click for Push Mode");

        pullMode = true;

        audioOutput->start(gen);

    }

}

void AudioTest::togglePlay()

{

    // toggle suspend/resume

    if(audioOutput->state() == QAudio::SuspendState) {

        qWarning()<<"status: Suspended, resume()";

        audioOutput->resume();

        button2->setText("Click To Suspend");

    } else if (audioOutput->state() == QAudio::ActiveState) {

        qWarning()<<"status: Active, suspend()";

        audioOutput->suspend();

        button2->setText("Click To Resume");

    } else if (audioOutput->state() == QAudio::StopState) {

        qWarning()<<"status: Stopped, resume()";

        audioOutput->resume();

        button2->setText("Click To Suspend");

    } else if (audioOutput->state() == QAudio::IdleState) {

        qWarning()<<"status: IdleState";

    }

}

void AudioTest::state(QAudio::State state)

{

    qWarning()<<" state="<<state;

}