/***************************************************************************
 *   Copyright (C) 2008-2016 by Ilya Kotov                                 *
 *   forkotov02@hotmail.ru                                                 *
 *                                                                         *
 *   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; either version 2 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 for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.         *
 ***************************************************************************/

#include <QIODevice>
#include <QBuffer>
#include <QTextCodec>
#include <taglib/id3v2tag.h>
#include <neaacdec.h>

#include "aacfile.h"

#define MAX_CHANNELS 6
#define AAC_BUFFER_SIZE 4096

static int adts_sample_rates[] = {96000,88200,64000,48000,44100,32000,24000,22050,16000,12000,11025,8000,7350,0,0,0};

AACFile::AACFile(QIODevice *input, bool metaData, bool adts)
{
    m_isValid = false;
    m_length = 0;
    m_bitrate = 0;
    m_samplerate = 0;
    m_input = input;
    m_offset = 0;
    char buf[AAC_BUFFER_SIZE];
    qint64 buf_at = input->peek((char *) buf, AAC_BUFFER_SIZE);

    //read id3v2 tag if possible
    if(!memcmp(buf, "ID3", 3))
    {
        TagLib::ByteVector byteVector(buf, sizeof(buf));
        TagLib::ID3v2::Header header(byteVector);

        if(input->isSequential())
        {
            if(header.tagSize() >= buf_at)
            {
                qWarning("AACFile: unable to parse id3v2");
                return;
            }

            if(metaData)
                parseID3v2(QByteArray(buf, header.tagSize()));

            buf_at = sizeof(buf) - header.tagSize();
            memmove(buf, buf + header.tagSize() + header.tagSize(), sizeof(buf) - header.tagSize());
        }
        else
        {
            if(metaData)
            {
                if(header.tagSize() <= buf_at)
                    parseID3v2(QByteArray(buf, header.tagSize()));
                else
                    parseID3v2(input->read(header.tagSize()));
            }

            input->seek(header.tagSize());
            buf_at = input->read(buf, sizeof(buf));
            input->seek(0); //restore inital position
        }

        m_offset += header.tagSize();
    }

    int adts_offset = 0;

    while(adts_offset < buf_at - 6)
    {
        //try to determnate header type;
        if ((uchar) buf[adts_offset] == 0xff && (((uchar)buf[adts_offset+1] & 0xf6) == 0xf0))
        {
            unsigned int frame_length = ((((unsigned int)buf[adts_offset+3] & 0x3)) << 11)
                    | (((unsigned int)buf[adts_offset+4]) << 3) | ((unsigned int)buf[adts_offset+5] >> 5);

            if(adts_offset + frame_length > buf_at - 6)
                break;

            //check second sync word
            if (((uchar)buf[adts_offset + frame_length] == 0xFF) &&
                    (((uchar)buf[adts_offset + frame_length + 1] & 0xF6) == 0xF0))
            {
                qDebug("AACFile: ADTS header found");
            }
            else
                break;

            if (!input->isSequential() && adts)
                parseADTS();
            m_isValid = true;
            m_offset += adts_offset;
            return;
        }
        adts_offset++;
    }

    if (memcmp(buf, "ADIF", 4) == 0)
    {
        qDebug("AACFile: ADIF header found");
        int skip_size = (buf[4] & 0x80) ? 9 : 0;
        m_bitrate = ((buf[4 + skip_size] & 0x0F)<<19) |
                (buf[5 + skip_size]<<11) |
                (buf[6 + skip_size]<<3) |
                (buf[7 + skip_size] & 0xE0);

        if (!input->isSequential ())
            m_length = (qint64) (((float)input->size()*8.f)/((float)m_bitrate) + 0.5f);
        else
            m_length = 0;
        m_bitrate = (int)((float)m_bitrate/1000.0f + 0.5f);
        m_isValid = true;
    }
}

AACFile::~AACFile()
{}

qint64 AACFile::length()
{
    return m_length;
}

quint32 AACFile::bitrate()
{
    return m_bitrate;
}

quint32 AACFile::samplerate()
{
    return m_samplerate;
}

int AACFile::offset() const
{
    return m_offset;
}

bool AACFile::isValid()
{
    return m_isValid;
}

const QMap<Qmmp::MetaData, QString> AACFile::metaData()
{
    return m_metaData;
}

void AACFile::parseADTS()
{
    uchar buf[FAAD_MIN_STREAMSIZE*MAX_CHANNELS];
    qint64 buf_at = 0;
    int frames, frame_length;
    int t_framelength = 0;
    float frames_per_sec, bytes_per_frame;
    qint64 pos = m_input->pos();

    m_input->seek(0);

    buf_at = m_input->read((char *)buf, FAAD_MIN_STREAMSIZE*MAX_CHANNELS);

    for (int i = 0; i < buf_at - 1; i++)
    {
        if (buf[i] == 0xff && (buf[i+1]&0xf6) == 0xf0)
        {
            memmove (buf, buf + i, buf_at - i);
            buf_at -= i;
            break;
        }
    }

    /* Read all frames to ensure correct time and bitrate */
    for (frames = 0; /* */; frames++)
    {
        //qDebug("frame header = %d", buf[0]);
        buf_at += m_input->read((char *)buf + buf_at, FAAD_MIN_STREAMSIZE*MAX_CHANNELS - buf_at);

        if (buf_at > 7)
        {
            /* check syncword */
            if (!((buf[0] == 0xFF)&&((buf[1] & 0xF6) == 0xF0)))
                break;

            if (frames == 0)
                m_samplerate = adts_sample_rates[(buf[2]&0x3c)>>2];

            frame_length = ((((unsigned int)buf[3] & 0x3)) << 11)
                           | (((unsigned int)buf[4]) << 3) | (buf[5] >> 5);

            t_framelength += frame_length;

            if (frame_length > buf_at)
                break;

            buf_at -= frame_length;
            memmove(buf, buf + frame_length, buf_at);
        }
        else
        {
            break;
        }
    }
    m_input->seek(pos);
    frames_per_sec = (float) m_samplerate/1024.0f;
    if (frames != 0)
        bytes_per_frame = (float)t_framelength/(float)(frames*1000);
    else
        bytes_per_frame = 0;
    m_bitrate = (quint32)(8. * bytes_per_frame * frames_per_sec + 0.5);

    if (frames_per_sec != 0)
        m_length = frames/frames_per_sec;
    else
        m_length = 1;

     m_input->seek(0); //restore inital position
}

void AACFile::parseID3v2(const QByteArray &data)
{
    ID3v2Tag taglib_tag(data);
    if (taglib_tag.isEmpty())
        return;

    TagLib::String album = taglib_tag.album();
    TagLib::String artist = taglib_tag.artist();
    TagLib::String comment = taglib_tag.comment();
    TagLib::String genre = taglib_tag.genre();
    TagLib::String title = taglib_tag.title();

    QTextCodec *codec = QTextCodec::codecForName ("UTF-8");
    bool utf = true;

    m_metaData.insert(Qmmp::ALBUM,
                      codec->toUnicode(album.toCString(utf)).trimmed());
    m_metaData.insert(Qmmp::ARTIST,
                      codec->toUnicode(artist.toCString(utf)).trimmed());
    m_metaData.insert(Qmmp::COMMENT,
                      codec->toUnicode(comment.toCString(utf)).trimmed());
    m_metaData.insert(Qmmp::GENRE,
                      codec->toUnicode(genre.toCString(utf)).trimmed());
    m_metaData.insert(Qmmp::TITLE,
                      codec->toUnicode(title.toCString(utf)).trimmed());
    m_metaData.insert(Qmmp::YEAR,
                      QString::number(taglib_tag.year()));
    m_metaData.insert(Qmmp::TRACK,
                      QString::number(taglib_tag.track()));
}

ID3v2Tag::ID3v2Tag(const QByteArray &array) : TagLib::ID3v2::Tag()
{
    m_buf = array;
    read();
}

void ID3v2Tag::read ()
{
    if(TagLib::ID3v2::Header::size() > (uint)m_buf.size())
        return;

    header()->setData(TagLib::ByteVector(m_buf.constData(), TagLib::ID3v2::Header::size()));

    if(header()->tagSize() > (uint)m_buf.size())
        return;

    TagLib::ByteVector v(m_buf.constData() + header()->size(), header()->tagSize());
    parse(v);
}