#include <stdlib.h>
#include <math.h>

#include <QDateTime>
#include <QDebug>
#include <QtMultimedia/QAudioDeviceInfo>
#include <QtMultimedia/QAudioInput>
#include <qendian.h>

#include "audioinfo.h"

AudioInfo::AudioInfo(const QAudioFormat &format, QObject *parent)
    :   QIODevice(parent)
    ,   m_format(format)
    ,   m_maxAmplitude(0)
    ,   m_level(0.0)

{
    switch (m_format.sampleSize()) {
    case 8:
        switch (m_format.sampleType()) {
        case QAudioFormat::UnSignedInt:
            m_maxAmplitude = 255;
            break;
        case QAudioFormat::SignedInt:
            m_maxAmplitude = 127;
            break;
        default:
            break;
        }
        break;
    case 16:
        switch (m_format.sampleType()) {
        case QAudioFormat::UnSignedInt:
            m_maxAmplitude = 65535;
            break;
        case QAudioFormat::SignedInt:
            m_maxAmplitude = 32767;
            break;
        default:
            break;
        }
        break;

    case 32:
        switch (m_format.sampleType()) {
        case QAudioFormat::UnSignedInt:
            m_maxAmplitude = 0xffffffff;
            break;
        case QAudioFormat::SignedInt:
            m_maxAmplitude = 0x7fffffff;
            break;
        case QAudioFormat::Float:
            m_maxAmplitude = 0x7fffffff; // Kind of
        default:
            break;
        }
        break;

    default:
        break;
    }
}

AudioInfo::~AudioInfo()
{
}

void AudioInfo::start()
{
    open(QIODevice::WriteOnly);
}

void AudioInfo::stop()
{
    close();
}

qint64 AudioInfo::readData(char *data, qint64 maxlen)
{
    Q_UNUSED(data)
    Q_UNUSED(maxlen)

    return 0;
}

qint64 AudioInfo::writeData(const char *data, qint64 len)
{
    if (m_maxAmplitude) {
        Q_ASSERT(m_format.sampleSize() % 8 == 0);
        const int channelBytes = m_format.sampleSize() / 8;
        const int sampleBytes = m_format.channelCount() * channelBytes;
        Q_ASSERT(len % sampleBytes == 0);
        const int numSamples = len / sampleBytes;

        quint32 maxValue = 0, minValue = 0;
        const unsigned char *ptr = reinterpret_cast<const unsigned char *>(data);

        for (int i = 0; i < numSamples; ++i) {
            for (int j = 0; j < m_format.channelCount(); ++j) {
                quint32 value = 0;

                if (m_format.sampleSize() == 8 && m_format.sampleType() == QAudioFormat::UnSignedInt) {
                    value = *reinterpret_cast<const quint8*>(ptr);
                } else if (m_format.sampleSize() == 8 && m_format.sampleType() == QAudioFormat::SignedInt) {
                    value = qAbs(*reinterpret_cast<const qint8*>(ptr));
                } else if (m_format.sampleSize() == 16 && m_format.sampleType() == QAudioFormat::UnSignedInt) {
                    if (m_format.byteOrder() == QAudioFormat::LittleEndian)
                        value = qFromLittleEndian<quint16>(ptr);
                    else
                        value = qFromBigEndian<quint16>(ptr);
                } else if (m_format.sampleSize() == 16 && m_format.sampleType() == QAudioFormat::SignedInt) {
                    if (m_format.byteOrder() == QAudioFormat::LittleEndian)
                        value = qAbs(qFromLittleEndian<qint16>(ptr));
                    else
                        value = qAbs(qFromBigEndian<qint16>(ptr));
                } else if (m_format.sampleSize() == 32 && m_format.sampleType() == QAudioFormat::UnSignedInt) {
                    if (m_format.byteOrder() == QAudioFormat::LittleEndian)
                        value = qFromLittleEndian<quint32>(ptr);
                    else
                        value = qFromBigEndian<quint32>(ptr);
                } else if (m_format.sampleSize() == 32 && m_format.sampleType() == QAudioFormat::SignedInt) {
                    if (m_format.byteOrder() == QAudioFormat::LittleEndian)
                        value = qAbs(qFromLittleEndian<qint32>(ptr));
                    else
                        value = qAbs(qFromBigEndian<qint32>(ptr));
                } else if (m_format.sampleSize() == 32 && m_format.sampleType() == QAudioFormat::Float) {
                    value = qAbs(*reinterpret_cast<const float*>(ptr) * 0x7fffffff); // assumes 0-1.0
                }

                maxValue = qMax(value, maxValue);
                minValue = qMin(value, minValue);
                ptr += channelBytes;
            }
        }

        minValue = qMax(minValue, (quint32) 0);
        maxValue = qMin(maxValue, m_maxAmplitude);
        m_level = qreal((maxValue + minValue) / 2) / m_maxAmplitude;
    }

    emit update();
    return len;
}