#include "mpegaudioframestream.h"

#include "../exceptions.h"
#include "../mediaformat.h"

#include <sstream>

using namespace std;
using namespace IoUtilities;
using namespace ConversionUtilities;
using namespace ChronoUtilities;

namespace Media {

/*!
 * \class Media::MpegAudioFrameStream
 * \brief Implementation of Media::AbstractTrack for a stream of
 *        MPEG audio frames (run-of-the-mill MP3 file).
 */

/*!
 * \brief Constructs a new track for the \a stream at the specified \a startOffset.
 */
MpegAudioFrameStream::MpegAudioFrameStream(iostream &stream, uint64 startOffset) :
    AbstractTrack(stream, startOffset)
{
    m_mediaType = MediaType::Acoustic;
}

/*!
 * \brief Destroys the track.
 */
MpegAudioFrameStream::~MpegAudioFrameStream()
{}

TrackType MpegAudioFrameStream::type() const
{
    return TrackType::MpegAudioFrameStream;
}

void MpegAudioFrameStream::internalParseHeader()
{
    const string context("parsing MPEG audio frame header");
    if(!m_istream) {
        throw NoDataFoundException();
    }
    // get size
    m_istream->seekg(-128, ios_base::end);
    if(m_reader.readUInt24BE() == 0x544147) {
        m_size = static_cast<uint64>(m_istream->tellg()) - 3u - m_startOffset;
    } else {
        m_size = static_cast<uint64>(m_istream->tellg()) + 125u - m_startOffset;
    }
    m_istream->seekg(m_startOffset, ios_base::beg);
    // parse frame header
    MpegAudioFrame frame;
    frame.parseHeader(*m_istream);
    m_version = frame.mpegVersion();
    switch(frame.layer()) {
    case 1:
        m_format = MediaFormat::MpegL1;
        break;
    case 2:
        m_format = MediaFormat::MpegL2;
        break;
    case 3:
        m_format = MediaFormat::MpegL3;
        break;
    default:
        m_format = MediaFormat::Unknown;
    }
    m_channelCount = frame.channelMode() == MpegChannelMode::SingleChannel ? 1 : 2;
    m_samplesPerSecond = frame.samperate();
    if(frame.isXingBytesfieldPresent()) {
        uint32 xingSize = frame.xingBytesfield();
        if(xingSize != m_size) {
            addNotification(NotificationType::Warning, "Real length MPEG of audio frames is not equal with value provided by Xing header. The Xing header value will be used.", context);
            m_size = xingSize;
        }
    }
    m_bitrate = frame.isXingFramefieldPresent()
            ? ((static_cast<double>(m_size) * 8.0) / (static_cast<double>(frame.xingFrameCount() * frame.sampleCount()) / static_cast<double>(frame.samperate())) / 1024.0)
            : frame.bitrate();
    m_bytesPerSecond = m_bitrate * 125;
    m_duration = TimeSpan::fromSeconds(static_cast<double>(m_size) / (m_bitrate * 128.0));
    m_frames.push_back(frame);
}

}