/*

 * HAPQA extract bitstream filter

 * Copyright (c) 2017 Jokyo Images

 *

 * 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

 */

/**

 * @file

 * HAPQA extract bitstream filter

 * extract one of the two textures of the HAQA

 */

#include "bsf.h"

#include "bsf_internal.h"

#include "bytestream.h"

#include "hap.h"

#include "libavutil/opt.h"

typedef struct HapqaExtractContext {

    const AVClass *class;

    int texture;/* index of the texture to keep (0 for rgb or 1 for alpha) */

} HapqaExtractContext;

static int check_texture(HapqaExtractContext *ctx, int section_type) {

    if (((ctx->texture == 0)&&((section_type & 0x0F) == 0x0F)) || /* HapQ texture and rgb extract */

        ((ctx->texture == 1)&&((section_type & 0x0F) == 0x01))) /* HapAlphaOnly texture and alpha extract */

    {

        return 1; /* the texture is the one to keep */

    } else {

        return 0;

    }

}

static int hapqa_extract(AVBSFContext *bsf, AVPacket *pkt)

{

    HapqaExtractContext *ctx = bsf->priv_data;

    GetByteContext gbc;

    int section_size;

    enum HapSectionType section_type;

    int start_section_size;

    int target_packet_size = 0;

    int ret = 0;

    ret = ff_bsf_get_packet_ref(bsf, pkt);

    if (ret < 0)

        return ret;

    bytestream2_init(&gbc, pkt->data, pkt->size);

    ret = ff_hap_parse_section_header(&gbc, &section_size, &section_type);

    if (ret != 0)

        goto fail;

    if ((section_type & 0x0F) != 0x0D) {

        av_log(bsf, AV_LOG_ERROR, "Invalid section type for HAPQA %#04x.\n", section_type & 0x0F);

        ret = AVERROR_INVALIDDATA;

        goto fail;

    }

    start_section_size = 4;

    bytestream2_seek(&gbc, start_section_size, SEEK_SET);/* go to start of the first texture */

    ret = ff_hap_parse_section_header(&gbc, &section_size, &section_type);

    if (ret != 0)

        goto fail;

    target_packet_size = section_size + 4;

    if (check_texture(ctx, section_type) == 0) { /* the texture is not the one to keep */

        start_section_size += 4 + section_size;

        bytestream2_seek(&gbc, start_section_size, SEEK_SET);/* go to start of the second texture */

        ret = ff_hap_parse_section_header(&gbc, &section_size, &section_type);

        if (ret != 0)

            goto fail;

        target_packet_size = section_size + 4;

        if (check_texture(ctx, section_type) == 0){ /* the second texture is not the one to keep */

            av_log(bsf, AV_LOG_ERROR, "No valid texture found.\n");

            ret = AVERROR_INVALIDDATA;

            goto fail;

        }

    }

    pkt->data += start_section_size;

    pkt->size = target_packet_size;

fail:

    if (ret < 0)

        av_packet_unref(pkt);

    return ret;

}

static const enum AVCodecID codec_ids[] = {

    AV_CODEC_ID_HAP, AV_CODEC_ID_NONE,

};

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

#define FLAGS (AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_BSF_PARAM)

static const AVOption options[] = {

    { "texture", "texture to keep", OFFSET(texture), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, FLAGS, .unit = "texture" },

        { "color", "keep HapQ texture",         0, AV_OPT_TYPE_CONST, { .i64 = 0 }, 0, 0, FLAGS, .unit = "texture" },

        { "alpha", "keep HapAlphaOnly texture", 0, AV_OPT_TYPE_CONST, { .i64 = 1 }, 0, 0, FLAGS, .unit = "texture" },

    { NULL },

};

static const AVClass hapqa_extract_class = {

    .class_name = "hapqa_extract_bsf",

    .item_name  = av_default_item_name,

    .option     = options,

    .version    = LIBAVUTIL_VERSION_INT,

};

const FFBitStreamFilter ff_hapqa_extract_bsf = {

    .p.name         = "hapqa_extract",

    .p.codec_ids    = codec_ids,

    .p.priv_class   = &hapqa_extract_class,

    .priv_data_size = sizeof(HapqaExtractContext),

    .filter         = hapqa_extract,

};