/*

 * QOI image format encoder

 *

 * 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 "libavutil/imgutils.h"

#include "avcodec.h"

#include "bytestream.h"

#include "codec_internal.h"

#include "encode.h"

#include "qoi.h"

static int qoi_encode_frame(AVCodecContext *avctx, AVPacket *pkt,

                            const AVFrame *pict, int *got_packet)

{

    const int channels = 3 + (avctx->pix_fmt == AV_PIX_FMT_RGBA);

    uint8_t px_prev[4] = { 0, 0, 0, 255 };

    uint8_t px[4] = { 0, 0, 0, 255 };

    uint8_t index[64][4] = { 0 };

    int64_t packet_size;

    uint8_t *buf;

    const uint8_t *src;

    int ret, run = 0;

    packet_size = avctx->width * avctx->height * (channels + 1LL) + 14LL + 8LL;

    if ((ret = ff_alloc_packet(avctx, pkt, packet_size)) < 0)

        return ret;

    buf = pkt->data;

    src = pict->data[0];

    bytestream_put_buffer(&buf, "qoif", 4);

    bytestream_put_be32(&buf, avctx->width);

    bytestream_put_be32(&buf, avctx->height);

    bytestream_put_byte(&buf, channels);

    bytestream_put_byte(&buf, avctx->color_trc == AVCOL_TRC_LINEAR);

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

        for (int x = 0; x < avctx->width; x++) {

            memcpy(px, src + x * channels, channels);

            if (!memcmp(px, px_prev, 4)) {

                run++;

                if (run == 62) {

                    bytestream_put_byte(&buf, QOI_OP_RUN | (run - 1));

                    run = 0;

                }

            } else {

                int index_pos;

                if (run > 0) {

                    bytestream_put_byte(&buf, QOI_OP_RUN | (run - 1));

                    run = 0;

                }

                index_pos = QOI_COLOR_HASH(px) & 63;

                if (!memcmp(index[index_pos], px, 4)) {

                    bytestream_put_byte(&buf, QOI_OP_INDEX | index_pos);

                } else {

                    memcpy(index[index_pos], px, 4);

                    if (px[3] == px_prev[3]) {

                        int8_t vr = px[0] - px_prev[0];

                        int8_t vg = px[1] - px_prev[1];

                        int8_t vb = px[2] - px_prev[2];

                        int8_t vg_r = vr - vg;

                        int8_t vg_b = vb - vg;

                        if (vr > -3 && vr < 2 &&

                            vg > -3 && vg < 2 &&

                            vb > -3 && vb < 2) {

                            bytestream_put_byte(&buf, QOI_OP_DIFF | (vr + 2) << 4 | (vg + 2) << 2 | (vb + 2));

                        } else if (vg_r >  -9 && vg_r <  8 &&

                                   vg   > -33 && vg   < 32 &&

                                   vg_b >  -9 && vg_b <  8) {

                            bytestream_put_byte(&buf, QOI_OP_LUMA     | (vg   + 32));

                            bytestream_put_byte(&buf, (vg_r + 8) << 4 | (vg_b +  8));

                        } else {

                            bytestream_put_byte(&buf, QOI_OP_RGB);

                            bytestream_put_byte(&buf, px[0]);

                            bytestream_put_byte(&buf, px[1]);

                            bytestream_put_byte(&buf, px[2]);

                        }

                    } else {

                        bytestream_put_byte(&buf, QOI_OP_RGBA);

                        bytestream_put_byte(&buf, px[0]);

                        bytestream_put_byte(&buf, px[1]);

                        bytestream_put_byte(&buf, px[2]);

                        bytestream_put_byte(&buf, px[3]);

                    }

                }

            }

            memcpy(px_prev, px, 4);

        }

        src += pict->linesize[0];

    }

    if (run)

        bytestream_put_byte(&buf, QOI_OP_RUN | (run - 1));

    bytestream_put_be64(&buf, 0x01);

    pkt->size = buf - pkt->data;

    *got_packet = 1;

    return 0;

}

const FFCodec ff_qoi_encoder = {

    .p.name         = "qoi",

    CODEC_LONG_NAME("QOI (Quite OK Image format) image"),

    .p.type         = AVMEDIA_TYPE_VIDEO,

    .p.id           = AV_CODEC_ID_QOI,

    .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS |

                      AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,

    FF_CODEC_ENCODE_CB(qoi_encode_frame),

    CODEC_PIXFMTS(AV_PIX_FMT_RGBA, AV_PIX_FMT_RGB24),

};