/*

 * Simon & Schuster Interactive VAG (de)muxer

 *

 * Copyright (C) 2020 Zane van Iperen (zane@zanevaniperen.com)

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg 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

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include "config_components.h"

#include "libavutil/channel_layout.h"

#include "avformat.h"

#include "avio_internal.h"

#include "demux.h"

#include "internal.h"

#include "mux.h"

#include "rawenc.h"

#include "libavutil/intreadwrite.h"

#define KVAG_TAG            MKTAG('K', 'V', 'A', 'G')

#define KVAG_HEADER_SIZE    14

#define KVAG_MAX_READ_SIZE  4096

typedef struct KVAGHeader {

    uint32_t    magic;

    uint32_t    data_size;

    int    sample_rate;

    uint16_t    stereo;

} KVAGHeader;

#if CONFIG_KVAG_DEMUXER

static int kvag_probe(const AVProbeData *p)

{

    if (AV_RL32(p->buf) != KVAG_TAG)

        return 0;

    return AVPROBE_SCORE_EXTENSION + 1;

}

static int kvag_read_header(AVFormatContext *s)

{

    int ret;

    AVStream *st;

    KVAGHeader hdr;

    AVCodecParameters *par;

    uint8_t buf[KVAG_HEADER_SIZE];

    if (!(st = avformat_new_stream(s, NULL)))

        return AVERROR(ENOMEM);

    if ((ret = ffio_read_size(s->pb, buf, KVAG_HEADER_SIZE)) < 0)

        return ret;

    hdr.magic                   = AV_RL32(buf +  0);

    hdr.data_size               = AV_RL32(buf +  4);

    hdr.sample_rate             = AV_RL32(buf +  8);

    hdr.stereo                  = AV_RL16(buf + 12);

    if (hdr.sample_rate <= 0)

        return AVERROR_INVALIDDATA;

    par                         = st->codecpar;

    par->codec_type             = AVMEDIA_TYPE_AUDIO;

    par->codec_id               = AV_CODEC_ID_ADPCM_IMA_SSI;

    par->format                 = AV_SAMPLE_FMT_S16;

    av_channel_layout_default(&par->ch_layout, !!hdr.stereo + 1);

    par->sample_rate            = hdr.sample_rate;

    par->bits_per_coded_sample  = 4;

    par->block_align            = 1;

    par->bit_rate               = par->ch_layout.nb_channels *

                                  (uint64_t)par->sample_rate *

                                  par->bits_per_coded_sample;

    avpriv_set_pts_info(st, 64, 1, par->sample_rate);

    st->start_time              = 0;

    st->duration                = hdr.data_size *

                                  (8 / par->bits_per_coded_sample) /

                                  par->ch_layout.nb_channels;

    return 0;

}

static int kvag_read_packet(AVFormatContext *s, AVPacket *pkt)

{

    int ret;

    AVCodecParameters *par = s->streams[0]->codecpar;

    if ((ret = av_get_packet(s->pb, pkt, KVAG_MAX_READ_SIZE)) < 0)

        return ret;

    pkt->flags          &= ~AV_PKT_FLAG_CORRUPT;

    pkt->stream_index   = 0;

    pkt->duration       = ret * (8 / par->bits_per_coded_sample) / par->ch_layout.nb_channels;

    return 0;

}

static int kvag_seek(AVFormatContext *s, int stream_index,

                     int64_t pts, int flags)

{

    if (pts != 0)

        return AVERROR(EINVAL);

    return avio_seek(s->pb, KVAG_HEADER_SIZE, SEEK_SET);

}

const FFInputFormat ff_kvag_demuxer = {

    .p.name         = "kvag",

    .p.long_name    = NULL_IF_CONFIG_SMALL("Simon & Schuster Interactive VAG"),

    .read_probe     = kvag_probe,

    .read_header    = kvag_read_header,

    .read_packet    = kvag_read_packet,

    .read_seek      = kvag_seek,

};

#endif

#if CONFIG_KVAG_MUXER

static int kvag_write_init(AVFormatContext *s)

{

    AVCodecParameters *par = s->streams[0]->codecpar;

    if (par->ch_layout.nb_channels > 2) {

        av_log(s, AV_LOG_ERROR, "KVAG files only support up to 2 channels\n");

        return AVERROR(EINVAL);

    }

    if (!(s->pb->seekable & AVIO_SEEKABLE_NORMAL)) {

        av_log(s, AV_LOG_WARNING, "Stream not seekable, unable to write output file\n");

        return AVERROR(EINVAL);

    }

    return 0;

}

static int kvag_write_header(AVFormatContext *s)

{

    uint8_t buf[KVAG_HEADER_SIZE];

    AVCodecParameters *par = s->streams[0]->codecpar;

    AV_WL32(buf +  0, KVAG_TAG);

    AV_WL32(buf +  4, 0); /* Data size, we fix this up later. */

    AV_WL32(buf +  8, par->sample_rate);

    AV_WL16(buf + 12, par->ch_layout.nb_channels == 2);

    avio_write(s->pb, buf, sizeof(buf));

    return 0;

}

static int kvag_write_trailer(AVFormatContext *s)

{

    int64_t file_size, data_size;

    file_size = avio_tell(s->pb);

    data_size = file_size - KVAG_HEADER_SIZE;

    if (data_size < UINT32_MAX) {

        avio_seek(s->pb, 4, SEEK_SET);

        avio_wl32(s->pb, (uint32_t)data_size);

        avio_seek(s->pb, file_size, SEEK_SET);

    } else {

        av_log(s, AV_LOG_WARNING,

               "Filesize %"PRId64" invalid for KVAG, output file will be broken\n",

               file_size);

    }

    return 0;

}

const FFOutputFormat ff_kvag_muxer = {

    .p.name         = "kvag",

    .p.long_name    = NULL_IF_CONFIG_SMALL("Simon & Schuster Interactive VAG"),

    .p.extensions   = "vag",

    .p.audio_codec  = AV_CODEC_ID_ADPCM_IMA_SSI,

    .p.video_codec  = AV_CODEC_ID_NONE,

    .p.subtitle_codec = AV_CODEC_ID_NONE,

    .flags_internal   = FF_OFMT_FLAG_MAX_ONE_OF_EACH |

                        FF_OFMT_FLAG_ONLY_DEFAULT_CODECS,

    .init           = kvag_write_init,

    .write_header   = kvag_write_header,

    .write_packet   = ff_raw_write_packet,

    .write_trailer  = kvag_write_trailer

};

#endif