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#include "wavedecoder.h"

#include <QtCore/qtimer.h>

#include <QtCore/qendian.h>

#include <QDebug>

WaveDecoder::WaveDecoder(QIODevice *s, QObject *parent):

    QIODevice(parent),

    haveFormat(false),

    dataSize(0),

    remaining(0),

    source(s)

{

    open(QIODevice::ReadOnly | QIODevice::Unbuffered);

    if (source->bytesAvailable() >= sizeof(CombinedHeader))

        QTimer::singleShot(0, this, SLOT(handleData()));

    else

        connect(source, SIGNAL(readyRead()), SLOT(handleData()));

}

WaveDecoder::~WaveDecoder()

{

}

QAudioFormat WaveDecoder::audioFormat() const

{

    return format;

}

int WaveDecoder::duration() const

{

    return size() * 1000 / (format.sampleSize() / 8) / format.channels() / format.frequency();

}

qint64 WaveDecoder::size() const

{

    return haveFormat ? dataSize : 0;

}

bool WaveDecoder::isSequential() const

{

    return source->isSequential();

}

qint64 WaveDecoder::bytesAvailable() const

{

    return haveFormat ? source->bytesAvailable() : 0;

}

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

{

    return haveFormat ? source->read(data, maxlen) : 0;

}

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

{

    Q_UNUSED(data);

    Q_UNUSED(len);

    return -1;

}

void WaveDecoder::handleData()

{

    if (source->bytesAvailable() < sizeof(CombinedHeader))

        return;

    source->disconnect(SIGNAL(readyRead()), this, SLOT(handleData()));

    source->read((char*)&header, sizeof(CombinedHeader));

    if (qstrncmp(header.riff.descriptor.id, "RIFF", 4) != 0 ||

        qstrncmp(header.riff.type, "WAVE", 4) != 0 ||

        qstrncmp(header.wave.descriptor.id, "fmt ", 4) != 0 ||

        (header.wave.audioFormat != 0 && header.wave.audioFormat != 1) ||

        qstrncmp(header.data.descriptor.id, "data", 4) != 0) {

        emit invalidFormat();

    }

    else {

        int bps = qFromLittleEndian<quint16>(header.wave.bitsPerSample);

        format.setCodec("audio/pcm");

        format.setSampleType(bps == 8 ? QAudioFormat::UnSignedInt : QAudioFormat::SignedInt);

        format.setByteOrder(QAudioFormat::LittleEndian);

        format.setFrequency(qFromLittleEndian<quint32>(header.wave.sampleRate));

        format.setSampleSize(bps);

        format.setChannels(qFromLittleEndian<quint16>(header.wave.numChannels));

        dataSize = qFromLittleEndian<quint32>(header.data.descriptor.size);

        haveFormat = true;

        connect(source, SIGNAL(readyRead()), SIGNAL(readyRead()));

        emit formatKnown();

    }

}