/*

 * Immersive Audio Model and Formats demuxer

 * Copyright (c) 2023 James Almer <jamrial@gmail.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 "libavutil/avassert.h"

#include "libavutil/intreadwrite.h"

#include "avformat.h"

#include "demux.h"

#include "iamf.h"

#include "iamf_reader.h"

#include "iamf_parse.h"

#include "internal.h"

//return < 0 if we need more data

static int get_score(const uint8_t *buf, int buf_size, enum IAMF_OBU_Type type, int *seq)

{

    if (type == IAMF_OBU_IA_SEQUENCE_HEADER) {

        if (buf_size < 4 || AV_RB32(buf) != MKBETAG('i','a','m','f'))

            return 0;

        *seq = 1;

        return -1;

    }

    if (type >= IAMF_OBU_IA_CODEC_CONFIG && type <= IAMF_OBU_IA_TEMPORAL_DELIMITER)

        return *seq ? -1 : 0;

    if (type >= IAMF_OBU_IA_AUDIO_FRAME && type <= IAMF_OBU_IA_AUDIO_FRAME_ID17)

        return *seq ? AVPROBE_SCORE_EXTENSION + 1 : 0;

    return 0;

}

static int iamf_probe(const AVProbeData *p)

{

    unsigned obu_size;

    enum IAMF_OBU_Type type;

    int seq = 0, cnt = 0, start_pos;

    int ret;

    while (1) {

        int size = ff_iamf_parse_obu_header(p->buf + cnt, p->buf_size - cnt,

                                            &obu_size, &start_pos, &type,

                                            NULL, NULL);

        if (size < 0)

            return 0;

        ret = get_score(p->buf + cnt + start_pos,

                        p->buf_size - cnt - start_pos,

                        type, &seq);

        if (ret >= 0)

            return ret;

        cnt += FFMIN(size, p->buf_size - cnt);

    }

    return 0;

}

static int iamf_read_header(AVFormatContext *s)

{

    IAMFDemuxContext *const c = s->priv_data;

    IAMFContext *const iamf = &c->iamf;

    int ret;

    ret = ff_iamfdec_read_descriptors(iamf, s->pb, INT_MAX, s);

    if (ret < 0)

        return ret;

    for (int i = 0; i < iamf->nb_audio_elements; i++) {

        IAMFAudioElement *audio_element = iamf->audio_elements[i];

        AVStreamGroup *stg = avformat_stream_group_create(s, AV_STREAM_GROUP_PARAMS_IAMF_AUDIO_ELEMENT, NULL);

        if (!stg)

            return AVERROR(ENOMEM);

        av_iamf_audio_element_free(&stg->params.iamf_audio_element);

        stg->id = audio_element->audio_element_id;

        /* Transfer ownership */

        stg->params.iamf_audio_element = audio_element->element;

        audio_element->element = NULL;

        for (int j = 0; j < audio_element->nb_substreams; j++) {

            IAMFSubStream *substream = &audio_element->substreams[j];

            AVStream *st = avformat_new_stream(s, NULL);

            if (!st)

                return AVERROR(ENOMEM);

            ret = avformat_stream_group_add_stream(stg, st);

            if (ret < 0)

                return ret;

            ret = avcodec_parameters_copy(st->codecpar, substream->codecpar);

            if (ret < 0)

                return ret;

            if (!i && !j && audio_element->layers[0].substream_count == 1)

                st->disposition |= AV_DISPOSITION_DEFAULT;

            else if (audio_element->nb_layers > 1 || audio_element->layers[0].substream_count > 1)

                st->disposition |= AV_DISPOSITION_DEPENDENT;

            st->id = substream->audio_substream_id;

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

        }

    }

    for (int i = 0; i < iamf->nb_mix_presentations; i++) {

        IAMFMixPresentation *mix_presentation = iamf->mix_presentations[i];

        AVStreamGroup *stg = avformat_stream_group_create(s, AV_STREAM_GROUP_PARAMS_IAMF_MIX_PRESENTATION, NULL);

        const AVIAMFMixPresentation *mix = mix_presentation->cmix;

        if (!stg)

            return AVERROR(ENOMEM);

        av_iamf_mix_presentation_free(&stg->params.iamf_mix_presentation);

        stg->id = mix_presentation->mix_presentation_id;

        /* Transfer ownership */

        stg->params.iamf_mix_presentation = mix_presentation->mix;

        mix_presentation->mix = NULL;

        for (int j = 0; j < mix->nb_submixes; j++) {

            const AVIAMFSubmix *sub_mix = mix->submixes[j];

            for (int k = 0; k < sub_mix->nb_elements; k++) {

                const AVIAMFSubmixElement *submix_element = sub_mix->elements[k];

                AVStreamGroup *audio_element = NULL;

                for (int l = 0; l < s->nb_stream_groups; l++)

                    if (s->stream_groups[l]->type == AV_STREAM_GROUP_PARAMS_IAMF_AUDIO_ELEMENT &&

                        s->stream_groups[l]->id == submix_element->audio_element_id) {

                        audio_element = s->stream_groups[l];

                        break;

                    }

                av_assert0(audio_element);

                for (int l = 0; l < audio_element->nb_streams; l++) {

                    ret = avformat_stream_group_add_stream(stg, audio_element->streams[l]);

                    if (ret < 0 && ret != AVERROR(EEXIST))

                        return ret;

                }

            }

        }

    }

    if (!s->nb_streams)

        return AVERROR_INVALIDDATA;

    return 0;

}

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

{

    IAMFDemuxContext *const c = s->priv_data;

    int ret;

    ret = ff_iamf_read_packet(s, c, s->pb, INT_MAX, 0, pkt);

    if (ret < 0)

        return ret;

    return 0;

}

static int iamf_read_close(AVFormatContext *s)

{

    IAMFDemuxContext *const c = s->priv_data;

    ff_iamf_read_deinit(c);

    return 0;

}

const FFInputFormat ff_iamf_demuxer = {

    .p.name         = "iamf",

    .p.long_name    = NULL_IF_CONFIG_SMALL("Raw Immersive Audio Model and Formats"),

    .p.extensions   = "iamf",

    .p.flags        = AVFMT_GENERIC_INDEX | AVFMT_NO_BYTE_SEEK | AVFMT_NOTIMESTAMPS | AVFMT_SHOW_IDS,

    .priv_data_size = sizeof(IAMFDemuxContext),

    .flags_internal = FF_INFMT_FLAG_INIT_CLEANUP,

    .read_probe     = iamf_probe,

    .read_header    = iamf_read_header,

    .read_packet    = iamf_read_packet,

    .read_close     = iamf_read_close,

};