/*
 * AV1 parser
 *
 * Copyright (C) 2018 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 "av1_parse.h"
#include "cbs.h"
#include "cbs_av1.h"
#include "parser.h"

typedef struct AV1ParseContext {
    CodedBitstreamContext *cbc;
    CodedBitstreamFragment temporal_unit;
    int parsed_extradata;
} AV1ParseContext;

static const enum AVPixelFormat pix_fmts_8bit[2][2] = {
    { AV_PIX_FMT_YUV444P, AV_PIX_FMT_NONE },
    { AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV420P },
};
static const enum AVPixelFormat pix_fmts_10bit[2][2] = {
    { AV_PIX_FMT_YUV444P10, AV_PIX_FMT_NONE },
    { AV_PIX_FMT_YUV422P10, AV_PIX_FMT_YUV420P10 },
};
static const enum AVPixelFormat pix_fmts_12bit[2][2] = {
    { AV_PIX_FMT_YUV444P12, AV_PIX_FMT_NONE },
    { AV_PIX_FMT_YUV422P12, AV_PIX_FMT_YUV420P12 },
};

static int av1_parser_parse(AVCodecParserContext *ctx,
                            AVCodecContext *avctx,
                            const uint8_t **out_data, int *out_size,
                            const uint8_t *data, int size)
{
    AV1ParseContext *s = ctx->priv_data;
    CodedBitstreamFragment *td = &s->temporal_unit;
    CodedBitstreamAV1Context *av1 = s->cbc->priv_data;
    int ret;

    *out_data = data;
    *out_size = size;

    ctx->key_frame         = -1;
    ctx->pict_type         = AV_PICTURE_TYPE_NONE;
    ctx->picture_structure = AV_PICTURE_STRUCTURE_UNKNOWN;

    s->cbc->log_ctx = avctx;

    if (avctx->extradata_size && !s->parsed_extradata) {
        s->parsed_extradata = 1;

        ret = ff_cbs_read(s->cbc, td, avctx->extradata, avctx->extradata_size);
        if (ret < 0) {
            av_log(avctx, AV_LOG_WARNING, "Failed to parse extradata.\n");
        }

        ff_cbs_fragment_uninit(s->cbc, td);
    }

    ret = ff_cbs_read(s->cbc, td, data, size);
    if (ret < 0) {
        av_log(avctx, AV_LOG_ERROR, "Failed to parse temporal unit.\n");
        goto end;
    }

    if (!av1->sequence_header) {
        av_log(avctx, AV_LOG_ERROR, "No sequence header available\n");
        goto end;
    }

    for (int i = 0; i < td->nb_units; i++) {
        CodedBitstreamUnit *unit = &td->units[i];
        AV1RawOBU *obu = unit->content;
        AV1RawSequenceHeader *seq = av1->sequence_header;
        AV1RawColorConfig *color = &seq->color_config;
        AV1RawFrameHeader *frame;
        int frame_type;

        if (unit->type == AV1_OBU_FRAME)
            frame = &obu->obu.frame.header;
        else if (unit->type == AV1_OBU_FRAME_HEADER)
            frame = &obu->obu.frame_header;
        else
            continue;

        if (frame->show_existing_frame) {
            AV1ReferenceFrameState *ref = &av1->ref[frame->frame_to_show_map_idx];

            if (!ref->valid) {
                av_log(avctx, AV_LOG_ERROR, "Invalid reference frame\n");
                goto end;
            }

            ctx->width  = ref->frame_width;
            ctx->height = ref->frame_height;
            frame_type  = ref->frame_type;

            ctx->key_frame = 0;
        } else if (!frame->show_frame) {
            continue;
        } else {
            ctx->width  = av1->frame_width;
            ctx->height = av1->frame_height;
            frame_type  = frame->frame_type;

            ctx->key_frame = frame_type == AV1_FRAME_KEY;
        }

        avctx->profile = seq->seq_profile;
        avctx->level   = seq->seq_level_idx[0];

        switch (frame_type) {
        case AV1_FRAME_KEY:
        case AV1_FRAME_INTRA_ONLY:
            ctx->pict_type = AV_PICTURE_TYPE_I;
            break;
        case AV1_FRAME_INTER:
            ctx->pict_type = AV_PICTURE_TYPE_P;
            break;
        case AV1_FRAME_SWITCH:
            ctx->pict_type = AV_PICTURE_TYPE_SP;
            break;
        }
        ctx->picture_structure = AV_PICTURE_STRUCTURE_FRAME;

        switch (av1->bit_depth) {
        case 8:
            ctx->format = color->mono_chrome ? AV_PIX_FMT_GRAY8
                                             : pix_fmts_8bit [color->subsampling_x][color->subsampling_y];
            break;
        case 10:
            ctx->format = color->mono_chrome ? AV_PIX_FMT_GRAY10
                                             : pix_fmts_10bit[color->subsampling_x][color->subsampling_y];
            break;
        case 12:
            ctx->format = color->mono_chrome ? AV_PIX_FMT_GRAY12
                                             : pix_fmts_12bit[color->subsampling_x][color->subsampling_y];
            break;
        }
        av_assert2(ctx->format != AV_PIX_FMT_NONE);
    }

end:
    ff_cbs_fragment_uninit(s->cbc, td);

    s->cbc->log_ctx = NULL;

    return size;
}

static const CodedBitstreamUnitType decompose_unit_types[] = {
    AV1_OBU_TEMPORAL_DELIMITER,
    AV1_OBU_SEQUENCE_HEADER,
    AV1_OBU_FRAME_HEADER,
    AV1_OBU_TILE_GROUP,
    AV1_OBU_FRAME,
};

static av_cold int av1_parser_init(AVCodecParserContext *ctx)
{
    AV1ParseContext *s = ctx->priv_data;
    int ret;

    ret = ff_cbs_init(&s->cbc, AV_CODEC_ID_AV1, NULL);
    if (ret < 0)
        return ret;

    s->cbc->decompose_unit_types    = (CodedBitstreamUnitType *)decompose_unit_types;
    s->cbc->nb_decompose_unit_types = FF_ARRAY_ELEMS(decompose_unit_types);

    return 0;
}

static void av1_parser_close(AVCodecParserContext *ctx)
{
    AV1ParseContext *s = ctx->priv_data;

    ff_cbs_close(&s->cbc);
}

static int av1_parser_split(AVCodecContext *avctx,
                            const uint8_t *buf, int buf_size)
{
    AV1OBU obu;
    const uint8_t *ptr = buf, *end = buf + buf_size;

    while (ptr < end) {
        int len = ff_av1_extract_obu(&obu, ptr, buf_size, avctx);
        if (len < 0)
            break;

        if (obu.type == AV1_OBU_FRAME_HEADER ||
            obu.type == AV1_OBU_FRAME) {
            return ptr - buf;
        }
        ptr      += len;
        buf_size -= len;
    }

    return 0;
}

AVCodecParser ff_av1_parser = {
    .codec_ids      = { AV_CODEC_ID_AV1 },
    .priv_data_size = sizeof(AV1ParseContext),
    .parser_init    = av1_parser_init,
    .parser_close   = av1_parser_close,
    .parser_parse   = av1_parser_parse,
    .split          = av1_parser_split,
};
