/*

 * Simbiosis game demuxer

 *

 * Copyright (C) 2021 Paul B Mahol

 *

 * 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 "avformat.h"

#include "demux.h"

#include "internal.h"

#include "libavutil/intreadwrite.h"

#include "libavutil/channel_layout.h"

#include "libavutil/internal.h"

#define IMX_TAG MKTAG('I', 'M', 'A', 'X')

typedef struct SimbiosisIMXDemuxContext {

    uint8_t pal[AVPALETTE_SIZE];

    int pal_changed;

    int64_t first_video_packet_pos;

} SimbiosisIMXDemuxContext;

static int simbiosis_imx_probe(const AVProbeData *p)

{

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

        return 0;

    if (AV_RN32(p->buf+4) == 0)

        return 0;

    if (AV_RN16(p->buf+8) == 0)

        return 0;

    if (AV_RL16(p->buf+10) != 0x102)

        return 0;

    return AVPROBE_SCORE_EXTENSION + 10;

}

static int simbiosis_imx_read_header(AVFormatContext *s)

{

    AVIOContext *pb = s->pb;

    AVStream *vst, *ast;

    int rate;

    vst = avformat_new_stream(s, NULL);

    ast = avformat_new_stream(s, NULL);

    if (!vst || !ast)

        return AVERROR(ENOMEM);

    avio_skip(pb, 4);

    vst->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;

    vst->codecpar->codec_tag  = 0;

    vst->codecpar->format     = AV_PIX_FMT_PAL8;

    vst->codecpar->codec_id   = AV_CODEC_ID_SIMBIOSIS_IMX;

    vst->start_time = 0;

    vst->duration =

    vst->nb_frames = avio_rl32(pb);

    rate = avio_rl16(pb);

    avio_skip(pb, 12);

    avpriv_set_pts_info(vst, 64, 1, rate);

    ast->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;

    ast->codecpar->codec_tag  = 0;

    ast->codecpar->codec_id   = AV_CODEC_ID_PCM_U8;

    ast->codecpar->ch_layout  = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;

    ast->codecpar->sample_rate = 22050;

    ast->start_time = 0;

    avpriv_set_pts_info(ast, 64, 1, 22050);

    return 0;

}

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

{

    AVIOContext *pb = s->pb;

    SimbiosisIMXDemuxContext *imx = s->priv_data;

    uint32_t chunk_size, chunk_type;

    int64_t pos = avio_tell(pb);

    int ret, idx = -1;

retry:

    if (avio_feof(pb))

        return AVERROR_EOF;

    chunk_size = avio_rl32(pb);

    chunk_type = avio_rl32(pb);

    switch (chunk_type) {

    case 0xAAFF:

        return AVERROR_EOF;

    case 0xAA99:

        idx = 1;

        break;

    case 0xAA97:

        idx = 0;

        if (!imx->first_video_packet_pos)

            imx->first_video_packet_pos = pos;

        break;

    case 0xAA98:

        if (chunk_size > 256 * 3)

            return AVERROR_INVALIDDATA;

        for (int i = 0; i < chunk_size / 3; i++) {

            unsigned r = avio_r8(pb) << 18;

            unsigned g = avio_r8(pb) << 10;

            unsigned b = avio_r8(pb) <<  2;

            AV_WL32(imx->pal + i * 4, (0xFFU << 24) | r | g | b);

        }

        imx->pal_changed = 1;

        idx = -1;

        break;

    default:

        return AVERROR_INVALIDDATA;

    }

    if (idx == -1)

        goto retry;

    ret = av_get_packet(pb, pkt, chunk_size);

    if (ret < 0)

        return ret;

    if (imx->pal_changed && idx == 0) {

        uint8_t *pal = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE,

                                               AVPALETTE_SIZE);

        if (!pal)

            return AVERROR(ENOMEM);

        memcpy(pal, imx->pal, AVPALETTE_SIZE);

        imx->pal_changed = 0;

        if (pos <= imx->first_video_packet_pos)

            pkt->flags |= AV_PKT_FLAG_KEY;

    } else if (idx == 1) {

        pkt->flags |= AV_PKT_FLAG_KEY;

    }

    pkt->pos = pos;

    pkt->stream_index = idx;

    pkt->duration = idx ? chunk_size : 1;

    return ret;

}

const FFInputFormat ff_simbiosis_imx_demuxer = {

    .p.name         = "simbiosis_imx",

    .p.long_name    = NULL_IF_CONFIG_SMALL("Simbiosis Interactive IMX"),

    .p.extensions   = "imx",

    .p.flags        = AVFMT_GENERIC_INDEX,

    .priv_data_size = sizeof(SimbiosisIMXDemuxContext),

    .read_probe     = simbiosis_imx_probe,

    .read_header    = simbiosis_imx_read_header,

    .read_packet    = simbiosis_imx_read_packet,

};