/*

 * 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/common.h"

#include "libavutil/opt.h"

#include "bsf.h"

#include "bsf_internal.h"

#include "cbs.h"

#include "cbs_bsf.h"

#include "cbs_h266.h"

#include "vvc.h"

#define IS_H266_SLICE(nut) (nut <= VVC_RASL_NUT || (nut >= VVC_IDR_W_RADL && nut <= VVC_GDR_NUT))

typedef struct H266MetadataContext {

    CBSBSFContext common;

    H266RawAUD aud_nal;

    int aud;

} H266MetadataContext;

static int h266_metadata_update_fragment(AVBSFContext *bsf, AVPacket *pkt,

                                         CodedBitstreamFragment *pu)

{

    H266MetadataContext *ctx = bsf->priv_data;

    int err, i;

    // If an AUD is present, it must be the first NAL unit.

    if (pu->nb_units && pu->units[0].type == VVC_AUD_NUT) {

        if (ctx->aud == BSF_ELEMENT_REMOVE)

            ff_cbs_delete_unit(pu, 0);

    } else if ( pkt && ctx->aud == BSF_ELEMENT_INSERT) {

        const H266RawSlice *first_slice = NULL;

        const H266RawPictureHeader *ph = NULL;

        H266RawAUD *aud = &ctx->aud_nal;

        int pic_type = 0, temporal_id = 8, layer_id = 0;

        for (i = 0; i < pu->nb_units; i++) {

            const H266RawNALUnitHeader *nal = pu->units[i].content;

            if (!nal)

                continue;

            if (nal->nuh_temporal_id_plus1 < temporal_id + 1)

                temporal_id = nal->nuh_temporal_id_plus1 - 1;

            if ( nal->nal_unit_type == VVC_PH_NUT ) {

                const H266RawPH *header = pu->units[i].content;

                ph = &header->ph_picture_header;

            } else if (IS_H266_SLICE(nal->nal_unit_type)) {

                const H266RawSlice *slice = pu->units[i].content;

                layer_id = nal->nuh_layer_id;

                if (slice->header.sh_slice_type == VVC_SLICE_TYPE_B &&

                    pic_type < 2)

                    pic_type = 2;

                if (slice->header.sh_slice_type == VVC_SLICE_TYPE_P &&

                    pic_type < 1)

                    pic_type = 1;

                if (!first_slice) {

                    first_slice = slice;

                    if (first_slice->header.

                        sh_picture_header_in_slice_header_flag)

                        ph = &first_slice->header.sh_picture_header;

                    else if (!ph)

                        break;

                }

            }

        }

        if (!ph) {

            av_log(bsf, AV_LOG_ERROR, "no available picture header");

            return AVERROR_INVALIDDATA;

        }

        aud->nal_unit_header = (H266RawNALUnitHeader) {

            .nal_unit_type         = VVC_AUD_NUT,

            .nuh_layer_id          = layer_id,

            .nuh_temporal_id_plus1 = temporal_id + 1,

        };

        aud->aud_pic_type = pic_type;

        aud->aud_irap_or_gdr_flag = ph->ph_gdr_or_irap_pic_flag;

        err = ff_cbs_insert_unit_content(pu, 0, VVC_AUD_NUT, aud, NULL);

        if (err < 0) {

            av_log(bsf, AV_LOG_ERROR, "Failed to insert AUD.\n");

            return err;

        }

    }

    /* TODO: implement more metadata parsing, like VUI, Levels etc. */

    //for (i = 0; i < pu->nb_units; i++) {

    //    if (pu->units[i].type == VVC_SPS_NUT) {

    //    }

    //}

    return 0;

}

static const CBSBSFType h266_metadata_type = {

    .codec_id        = AV_CODEC_ID_VVC,

    .fragment_name   = "access unit",

    .unit_name       = "NAL unit",

    .update_fragment = &h266_metadata_update_fragment,

};

static int h266_metadata_init(AVBSFContext *bsf)

{

    return ff_cbs_bsf_generic_init(bsf, &h266_metadata_type);

}

#define OFFSET(x) offsetof(H266MetadataContext, x)

#define FLAGS (AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_BSF_PARAM)

static const AVOption h266_metadata_options[] = {

    BSF_ELEMENT_OPTIONS_PIR("aud", "Access Unit Delimiter NAL units",

                            aud, FLAGS),

    { NULL }

};

static const AVClass h266_metadata_class = {

    .class_name = "h266_metadata_bsf",

    .item_name  = av_default_item_name,

    .option     = h266_metadata_options,

    .version    = LIBAVUTIL_VERSION_INT,

};

static const enum AVCodecID h266_metadata_codec_ids[] = {

    AV_CODEC_ID_VVC, AV_CODEC_ID_NONE,

};

const FFBitStreamFilter ff_vvc_metadata_bsf = {

    .p.name         = "vvc_metadata",

    .p.codec_ids    = h266_metadata_codec_ids,

    .p.priv_class   = &h266_metadata_class,

    .priv_data_size = sizeof(H266MetadataContext),

    .init           = &h266_metadata_init,

    .close          = &ff_cbs_bsf_generic_close,

    .filter         = &ff_cbs_bsf_generic_filter,

};