/*

 * Rayman 2 APM (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 "avformat.h"

#include "avio_internal.h"

#include "demux.h"

#include "internal.h"

#include "mux.h"

#include "rawenc.h"

#include "libavutil/channel_layout.h"

#include "libavutil/internal.h"

#include "libavutil/intreadwrite.h"

#define APM_FILE_HEADER_SIZE    20

#define APM_FILE_EXTRADATA_SIZE 80

#define APM_EXTRADATA_SIZE      28

#define APM_MAX_READ_SIZE       4096

#define APM_TAG_CODEC           0x2000

#define APM_TAG_VS12            MKTAG('v', 's', '1', '2')

#define APM_TAG_DATA            MKTAG('D', 'A', 'T', 'A')

typedef struct APMState {

    int32_t     has_saved;

    int32_t     predictor_r;

    int32_t     step_index_r;

    int32_t     saved_r;

    int32_t     predictor_l;

    int32_t     step_index_l;

    int32_t     saved_l;

} APMState;

typedef struct APMExtraData {

    uint32_t    magic;

    uint32_t    file_size;

    uint32_t    data_size;

    uint32_t    unk1;

    uint32_t    unk2;

    APMState    state;

    uint32_t    unk3[7];

    uint32_t    data;

} APMExtraData;

#if CONFIG_APM_DEMUXER

static void apm_parse_extradata(APMExtraData *ext, const uint8_t *buf)

{

    ext->magic              = AV_RL32(buf + 0);

    ext->file_size          = AV_RL32(buf + 4);

    ext->data_size          = AV_RL32(buf + 8);

    ext->unk1               = AV_RL32(buf + 12);

    ext->unk2               = AV_RL32(buf + 16);

    ext->state.has_saved    = AV_RL32(buf + 20);

    ext->state.predictor_r  = AV_RL32(buf + 24);

    ext->state.step_index_r = AV_RL32(buf + 28);

    ext->state.saved_r      = AV_RL32(buf + 32);

    ext->state.predictor_l  = AV_RL32(buf + 36);

    ext->state.step_index_l = AV_RL32(buf + 40);

    ext->state.saved_l      = AV_RL32(buf + 44);

    for (int i = 0; i < FF_ARRAY_ELEMS(ext->unk3); i++)

        ext->unk3[i]        = AV_RL32(buf + 48 + (i * 4));

    ext->data               = AV_RL32(buf + 76);

}

static int apm_probe(const AVProbeData *p)

{

    if (AV_RL16(p->buf) != APM_TAG_CODEC)

        return 0;

    if (p->buf_size < 100)

        return 0;

    if (AV_RL32(p->buf + 20) != APM_TAG_VS12)

        return 0;

    if (AV_RL32(p->buf + 96) != APM_TAG_DATA)

        return 0;

    return AVPROBE_SCORE_MAX - 1;

}

static int apm_read_header(AVFormatContext *s)

{

    int64_t ret;

    AVStream *st;

    APMExtraData extradata;

    AVCodecParameters *par;

    uint8_t buf[APM_FILE_EXTRADATA_SIZE];

    int channels;

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

        return AVERROR(ENOMEM);

    /*

     * This is 98% a WAVEFORMATEX, but there's something screwy with the extradata

     * that ff_get_wav_header() can't (and shouldn't) handle properly.

     */

    if (avio_rl16(s->pb) != APM_TAG_CODEC)

        return AVERROR_INVALIDDATA;

    par = st->codecpar;

    channels                   = avio_rl16(s->pb);

    par->sample_rate           = avio_rl32(s->pb);

    /* Skip the bitrate, it's usually wrong anyway. */

    if ((ret = avio_skip(s->pb, 4)) < 0)

        return ret;

    par->block_align           = avio_rl16(s->pb);

    par->bits_per_coded_sample = avio_rl16(s->pb);

    if (avio_rl32(s->pb) != APM_FILE_EXTRADATA_SIZE)

        return AVERROR_INVALIDDATA;

    /* 8 = bits per sample * max channels */

    if (par->sample_rate > (INT_MAX / 8))

        return AVERROR_INVALIDDATA;

    if (par->bits_per_coded_sample != 4)

        return AVERROR_INVALIDDATA;

    if (channels > 2 || channels == 0)

        return AVERROR_INVALIDDATA;

    av_channel_layout_default(&par->ch_layout, channels);

    par->codec_type            = AVMEDIA_TYPE_AUDIO;

    par->codec_id              = AV_CODEC_ID_ADPCM_IMA_APM;

    par->format                = AV_SAMPLE_FMT_S16;

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

                                 (int64_t)par->sample_rate *

                                 par->bits_per_coded_sample;

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

        return ret;

    apm_parse_extradata(&extradata, buf);

    if (extradata.magic != APM_TAG_VS12 || extradata.data != APM_TAG_DATA)

        return AVERROR_INVALIDDATA;

    if (extradata.state.has_saved) {

        avpriv_request_sample(s, "Saved Samples");

        return AVERROR_PATCHWELCOME;

    }

    if ((ret = ff_alloc_extradata(par, APM_EXTRADATA_SIZE)) < 0)

        return ret;

    /* Use the entire state as extradata. */

    memcpy(par->extradata, buf + 20, APM_EXTRADATA_SIZE);

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

    st->start_time  = 0;

    st->duration    = extradata.data_size *

                      (8 / par->bits_per_coded_sample) /

                      par->ch_layout.nb_channels;

    return 0;

}

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

{

    int ret;

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

    /*

     * For future reference: if files with the `has_saved` field set ever

     * surface, `saved_l`, and `saved_r` will each contain 8 "saved" samples

     * that should be sent to the decoder before the actual data.

     */

    if ((ret = av_get_packet(s->pb, pkt, APM_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;

}

const FFInputFormat ff_apm_demuxer = {

    .p.name         = "apm",

    .p.long_name    = NULL_IF_CONFIG_SMALL("Ubisoft Rayman 2 APM"),

    .read_probe     = apm_probe,

    .read_header    = apm_read_header,

    .read_packet    = apm_read_packet

};

#endif

#if CONFIG_APM_MUXER

static int apm_write_init(AVFormatContext *s)

{

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

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

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

        return AVERROR(EINVAL);

    }

    if (par->sample_rate > (INT_MAX / 8)) {

        av_log(s, AV_LOG_ERROR, "Sample rate too large\n");

        return AVERROR(EINVAL);

    }

    if (par->extradata_size != APM_EXTRADATA_SIZE) {

        av_log(s, AV_LOG_ERROR, "Invalid/missing extradata\n");

        return AVERROR(EINVAL);

    }

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

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

        return AVERROR(EINVAL);

    }

    return 0;

}

static int apm_write_header(AVFormatContext *s)

{

    uint8_t buf[APM_FILE_EXTRADATA_SIZE] = { 0 };

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

    /*

     * Bodge a WAVEFORMATEX manually, ff_put_wav_header() can't

     * be used because of the extra 2 bytes.

     */

    avio_wl16(s->pb, APM_TAG_CODEC);

    avio_wl16(s->pb, par->ch_layout.nb_channels);

    avio_wl32(s->pb, par->sample_rate);

    /* This is the wrong calculation, but it's what the original files have. */

    avio_wl32(s->pb, par->sample_rate * par->ch_layout.nb_channels * 2);

    avio_wl16(s->pb, par->block_align);

    avio_wl16(s->pb, par->bits_per_coded_sample);

    avio_wl32(s->pb, APM_FILE_EXTRADATA_SIZE);

    /*

     * Build the extradata. Assume the codec's given us correct data.

     * File and data sizes are fixed later.

     */

    AV_WL32(buf +  0, APM_TAG_VS12); /* magic */

    AV_WL32(buf + 12, 0xFFFFFFFF);   /* unk1  */

    memcpy( buf + 20, par->extradata, APM_EXTRADATA_SIZE);

    AV_WL32(buf + 76, APM_TAG_DATA); /* data */

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

    return 0;

}

static int apm_write_trailer(AVFormatContext *s)

{

    int64_t file_size, data_size;

    file_size = avio_tell(s->pb);

    data_size = file_size - (APM_FILE_HEADER_SIZE + APM_FILE_EXTRADATA_SIZE);

    if (file_size >= UINT32_MAX) {

        av_log(s, AV_LOG_ERROR,

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

               file_size);

        return AVERROR(ERANGE);

    }

    avio_seek(s->pb, 24, SEEK_SET);

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

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

    return 0;

}

const FFOutputFormat ff_apm_muxer = {

    .p.name         = "apm",

    .p.long_name    = NULL_IF_CONFIG_SMALL("Ubisoft Rayman 2 APM"),

    .p.extensions   = "apm",

    .p.audio_codec  = AV_CODEC_ID_ADPCM_IMA_APM,

    .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           = apm_write_init,

    .write_header   = apm_write_header,

    .write_packet   = ff_raw_write_packet,

    .write_trailer  = apm_write_trailer

};

#endif