/*

 * PDV video format

 *

 * Copyright (c) 2023 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 "avcodec.h"

#include "codec_internal.h"

#include "decode.h"

#include "zlib_wrapper.h"

#include "libavutil/attributes.h"

#include <zlib.h>

typedef struct PDVContext {

    AVFrame  *previous_frame;

    FFZStream zstream;

} PDVContext;

static av_cold int decode_init(AVCodecContext *avctx)

{

    PDVContext *s = avctx->priv_data;

    avctx->pix_fmt = AV_PIX_FMT_MONOBLACK;

    s->previous_frame = av_frame_alloc();

    if (!s->previous_frame)

        return AVERROR(ENOMEM);

    return ff_inflate_init(&s->zstream, avctx);

}

static av_cold int decode_end(AVCodecContext *avctx)

{

    PDVContext *s = avctx->priv_data;

    av_frame_free(&s->previous_frame);

    ff_inflate_end(&s->zstream);

    return 0;

}

static int decode_frame(AVCodecContext *avctx, AVFrame *frame,

                        int *got_frame, AVPacket *avpkt)

{

    PDVContext *s = avctx->priv_data;

    AVFrame *prev_frame = s->previous_frame;

    z_stream *const zstream = &s->zstream.zstream;

    uint8_t *dst, *prev = prev_frame->data[0];

    int ret, zret;

    if (avctx->skip_frame >= AVDISCARD_ALL ||

        (avctx->skip_frame >= AVDISCARD_NONINTRA &&

         !(avpkt->flags & AV_PKT_FLAG_KEY)))

        return avpkt->size;

    zret = inflateReset(zstream);

    if (zret != Z_OK) {

        av_log(avctx, AV_LOG_ERROR, "Could not reset inflate: %d.\n", zret);

        return AVERROR_INVALIDDATA;

    }

    if (avpkt->size * 1032LL < ((avctx->width + 7) >> 3) * avctx->height) //Asymptotic max compression of deflate

        return AVERROR_INVALIDDATA;

    if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)

        return ret;

    zstream->next_in  = avpkt->data;

    zstream->avail_in = avpkt->size;

    dst = frame->data[0];

    for (int i = 0; i < avctx->height; i++) {

        zstream->next_out  = dst;

        zstream->avail_out = (avctx->width + 7) >> 3;

        zret = inflate(zstream, Z_SYNC_FLUSH);

        if (zret != Z_OK && zret != Z_STREAM_END) {

            av_log(avctx, AV_LOG_ERROR,

                   "Inflate failed with return code: %d.\n", zret);

            return AVERROR_INVALIDDATA;

        }

        if (prev && !(avpkt->flags & AV_PKT_FLAG_KEY)) {

            for (int j = 0; j < (avctx->width + 7) >> 3; j++)

                dst[j] ^= prev[j];

            prev += prev_frame->linesize[0];

        }

        dst += frame->linesize[0];

    }

    if ((ret = av_frame_replace(s->previous_frame, frame)) < 0)

        return ret;

    if (avpkt->flags & AV_PKT_FLAG_KEY) {

        frame->flags |= AV_FRAME_FLAG_KEY;

        frame->pict_type = AV_PICTURE_TYPE_I;

    } else {

        frame->pict_type = AV_PICTURE_TYPE_P;

    }

    *got_frame       = 1;

    return avpkt->size;

}

static av_cold void decode_flush(AVCodecContext *avctx)

{

    PDVContext *s = avctx->priv_data;

    av_frame_unref(s->previous_frame);

}

const FFCodec ff_pdv_decoder = {

    .p.name         = "pdv",

    CODEC_LONG_NAME("PDV (PlayDate Video)"),

    .priv_data_size = sizeof(PDVContext),

    .p.type         = AVMEDIA_TYPE_VIDEO,

    .p.id           = AV_CODEC_ID_PDV,

    .p.capabilities = AV_CODEC_CAP_DR1,

    .caps_internal  = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM |

                      FF_CODEC_CAP_INIT_CLEANUP,

    .init           = decode_init,

    .close          = decode_end,

    .flush          = decode_flush,

    FF_CODEC_DECODE_CB(decode_frame),

};