/* GStreamer

 * Copyright (C) 2025 Fluendo S.A.

 *   Author: Diego Nieto <dnieto@fluendo.com>

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Library General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library 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

 * Library General Public License for more details.

 *

 * You should have received a copy of the GNU Library General Public

 * License along with this library; if not, write to the

 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,

 * Boston, MA 02110-1301, USA.

 */

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include "gstvideodscmeta.h"

#ifndef GST_DISABLE_GST_DEBUG

#define GST_CAT_DEFAULT gst_video_dsc_meta_debug_category_get()

static GstDebugCategory *

gst_video_dsc_meta_debug_category_get (void)

{

  static gsize cat_gonce = 0;

  if (g_once_init_enter (&cat_gonce)) {

    GstDebugCategory *cat = NULL;

    GST_DEBUG_CATEGORY_INIT (cat,

        "videodscmeta", 0, "Video Digitally Signed Content Meta");

    g_once_init_leave (&cat_gonce, (gsize) cat);

  }

  return (GstDebugCategory *) cat_gonce;

}

#endif /* GST_DISABLE_GST_DEBUG */

/**

 * SECTION:gstvideodscmeta

 * @title: GstVideoDSCMeta

 * @short_description: GstMeta for Digitally Signed Content SEI messages

 *

 * This meta carries Digitally Signed Content (DSC) SEI message information

 * for video streams. DSC allows the verification of the integrity and authenticity

 * of the video content.

 * 

 * The mechanism is realized through three supplemental enhancement information (SEI)

 * messages that enable attaching cryptographic signatures to flexible chunks of data

 * within a video stream at the Network Abstraction Layer (NAL) unit level.

 * 

 * The current implementation follows the specification defined in

 * https://www.jvet-experts.org/doc_end_user/documents/40_Geneva/wg11/JVET-AN1019-v1.zip

 * 

 * The main concepts and mechanisms are also described in the paper:

 * https://www.hhi.fraunhofer.de/fileadmin/Events/2025/IBC_2025/IBC2025PaperAuthentication_HHI.pdf

 * 

 * Three types of metadata are provided:

 * - Initialization: Contains hash method, key source, and verification settings

 * - Selection: Indicates which verification substream to use

 * - Verification: Contains the actual signature data for verification

 *

 * Since: 1.30

 */

/* ==================== Initialization Meta ==================== */

typedef struct

{

  const GstH274DigitallySignedContentInitialization *dsc_initialization;

} GstVideoDSCInitializationMetaParams;

GType

gst_video_dsc_initialization_meta_api_get_type (void)

{

  static GType type = 0;

  static const gchar *tags[] = { GST_META_TAG_VIDEO_STR, NULL };

  if (g_once_init_enter (&type)) {

    GType _type =

        gst_meta_api_type_register ("GstVideoDSCInitializationMetaAPI", tags);

    g_once_init_leave (&type, _type);

  }

  return type;

}

static gboolean

gst_video_dsc_initialization_meta_transform (GstBuffer *

    dest, GstMeta * meta, GstBuffer * buffer, GQuark type, gpointer data)

{

  GstVideoDSCInitializationMeta *dmeta, *smeta;

  smeta = (GstVideoDSCInitializationMeta *) meta;

  if (GST_META_TRANSFORM_IS_COPY (type)) {

    dmeta =

        gst_buffer_add_video_dsc_initialization_meta (dest,

        &smeta->dsc_initialization);

    if (!dmeta)

      return FALSE;

  }

  return TRUE;

}

static gboolean

gst_video_dsc_initialization_meta_init (GstMeta * meta,

    gpointer params, GstBuffer * buffer)

{

  GstVideoDSCInitializationMeta *dsc_meta =

      (GstVideoDSCInitializationMeta *) meta;

  GstVideoDSCInitializationMetaParams *p =

      (GstVideoDSCInitializationMetaParams *) params;

  gst_h274_dsc_initialization_copy (&dsc_meta->dsc_initialization,

      p->dsc_initialization);

  return TRUE;

}

static void

gst_video_dsc_initialization_meta_free (GstMeta * meta, GstBuffer * buffer)

{

  GstVideoDSCInitializationMeta *dsc_meta =

      (GstVideoDSCInitializationMeta *) meta;

  gst_h274_dsc_initialization_free (&dsc_meta->dsc_initialization);

}

const GstMetaInfo *

gst_video_dsc_initialization_meta_get_info (void)

{

  static const GstMetaInfo *info = NULL;

  if (g_once_init_enter ((GstMetaInfo **) & info)) {

    const GstMetaInfo *meta =

        gst_meta_register (GST_VIDEO_DSC_INITIALIZATION_META_API_TYPE,

        "GstVideoDSCInitializationMeta",

        sizeof (GstVideoDSCInitializationMeta),

        gst_video_dsc_initialization_meta_init,

        gst_video_dsc_initialization_meta_free,

        gst_video_dsc_initialization_meta_transform);

    g_once_init_leave ((GstMetaInfo **) & info, (GstMetaInfo *) meta);

  }

  return info;

}

GstVideoDSCInitializationMeta *

gst_buffer_add_video_dsc_initialization_meta (GstBuffer *

    buffer,

    const GstH274DigitallySignedContentInitialization * dsc_initialization)

{

  GstVideoDSCInitializationMeta *meta;

  GstVideoDSCInitializationMetaParams params = {

    .dsc_initialization = dsc_initialization,

  };

  g_return_val_if_fail (buffer != NULL, NULL);

  g_return_val_if_fail (dsc_initialization != NULL, NULL);

  GST_DEBUG ("Adding DSC Initialization Meta: id=%u, hash_method_type=%u, "

      "key_retrieval_mode_idc=%u, use_key_register_idx_flag=%d, "

      "key_register_idx=%u, content_uuid_present_flag=%d, "

      "num_verification_substreams=%u, ref_substream_flag_len=%" G_GSIZE_FORMAT

      ", vss_implicit_association_mode_flag=%d, "

      "signed_content_start_flag=%d, sei_signing_flag=%d, key_source_uri=%s",

      dsc_initialization->id, dsc_initialization->hash_method_type,

      dsc_initialization->key_retrieval_mode_idc,

      dsc_initialization->use_key_register_idx_flag,

      dsc_initialization->key_register_idx,

      dsc_initialization->content_uuid_present_flag,

      dsc_initialization->num_verification_substreams,

      dsc_initialization->ref_substream_flag_len,

      dsc_initialization->vss_implicit_association_mode_flag,

      dsc_initialization->signed_content_start_flag,

      dsc_initialization->sei_signing_flag,

      GST_STR_NULL (dsc_initialization->key_source_uri));

  if (dsc_initialization->content_uuid_present_flag) {

    GST_MEMDUMP ("Content UUID", dsc_initialization->content_uuid, 16);

  }

  params.dsc_initialization = dsc_initialization;

  meta = (GstVideoDSCInitializationMeta *)

      gst_buffer_add_meta (buffer,

      GST_VIDEO_DSC_INITIALIZATION_META_INFO, &params);

  return meta;

}

/* ==================== Selection Meta ==================== */

typedef struct

{

  const GstH274DigitallySignedContentSelection *dsc_selection;

} GstVideoDSCSelectionMetaParams;

GType

gst_video_dsc_selection_meta_api_get_type (void)

{

  static GType type = 0;

  static const gchar *tags[] = { GST_META_TAG_VIDEO_STR, NULL };

  if (g_once_init_enter (&type)) {

    GType _type =

        gst_meta_api_type_register ("GstVideoDSCSelectionMetaAPI", tags);

    g_once_init_leave (&type, _type);

  }

  return type;

}

static gboolean

gst_video_dsc_selection_meta_transform (GstBuffer * dest,

    GstMeta * meta, GstBuffer * buffer, GQuark type, gpointer data)

{

  GstVideoDSCSelectionMeta *dmeta, *smeta;

  smeta = (GstVideoDSCSelectionMeta *) meta;

  if (GST_META_TRANSFORM_IS_COPY (type)) {

    dmeta = gst_buffer_add_video_dsc_selection_meta (dest,

        &smeta->dsc_selection);

    if (!dmeta)

      return FALSE;

  }

  return TRUE;

}

static gboolean

gst_video_dsc_selection_meta_init (GstMeta * meta,

    gpointer params, GstBuffer * buffer)

{

  GstVideoDSCSelectionMeta *dsc_meta = (GstVideoDSCSelectionMeta *) meta;

  GstVideoDSCSelectionMetaParams *p = (GstVideoDSCSelectionMetaParams *) params;

  gst_h274_dsc_selection_copy (&dsc_meta->dsc_selection, p->dsc_selection);

  return TRUE;

}

static void

gst_video_dsc_selection_meta_free (GstMeta * meta, GstBuffer * buffer)

{

  GstVideoDSCSelectionMeta *dsc_meta = (GstVideoDSCSelectionMeta *) meta;

  gst_h274_dsc_selection_free (&dsc_meta->dsc_selection);

}

const GstMetaInfo *

gst_video_dsc_selection_meta_get_info (void)

{

  static const GstMetaInfo *info = NULL;

  if (g_once_init_enter ((GstMetaInfo **) & info)) {

    const GstMetaInfo *meta =

        gst_meta_register (GST_VIDEO_DSC_SELECTION_META_API_TYPE,

        "GstVideoDSCSelectionMeta",

        sizeof (GstVideoDSCSelectionMeta),

        gst_video_dsc_selection_meta_init,

        gst_video_dsc_selection_meta_free,

        gst_video_dsc_selection_meta_transform);

    g_once_init_leave ((GstMetaInfo **) & info, (GstMetaInfo *) meta);

  }

  return info;

}

GstVideoDSCSelectionMeta *

gst_buffer_add_video_dsc_selection_meta (GstBuffer * buffer,

    const GstH274DigitallySignedContentSelection * dsc_selection)

{

  GstVideoDSCSelectionMeta *meta;

  GstVideoDSCSelectionMetaParams params = {

    .dsc_selection = dsc_selection,

  };

  g_return_val_if_fail (buffer != NULL, NULL);

  g_return_val_if_fail (dsc_selection != NULL, NULL);

  GST_DEBUG ("Adding DSC Selection Meta: id=%u, verification_substream_id=%u",

      dsc_selection->id, dsc_selection->verification_substream_id);

  params.dsc_selection = dsc_selection;

  meta = (GstVideoDSCSelectionMeta *)

      gst_buffer_add_meta (buffer, GST_VIDEO_DSC_SELECTION_META_INFO, &params);

  return meta;

}

/* ==================== Verification Meta ==================== */

typedef struct

{

  const GstH274DigitallySignedContentVerification *dsc_verification;

} GstVideoDSCVerificationMetaParams;

GType

gst_video_dsc_verification_meta_api_get_type (void)

{

  static GType type = 0;

  static const gchar *tags[] = { GST_META_TAG_VIDEO_STR, NULL };

  if (g_once_init_enter (&type)) {

    GType _type =

        gst_meta_api_type_register ("GstVideoDSCVerificationMetaAPI", tags);

    g_once_init_leave (&type, _type);

  }

  return type;

}

static gboolean

gst_video_dsc_verification_meta_transform (GstBuffer * dest,

    GstMeta * meta, GstBuffer * buffer, GQuark type, gpointer data)

{

  GstVideoDSCVerificationMeta *dmeta, *smeta;

  smeta = (GstVideoDSCVerificationMeta *) meta;

  if (GST_META_TRANSFORM_IS_COPY (type)) {

    dmeta = gst_buffer_add_video_dsc_verification_meta (dest,

        &smeta->dsc_verification);

    if (!dmeta)

      return FALSE;

  }

  return TRUE;

}

static gboolean

gst_video_dsc_verification_meta_init (GstMeta * meta,

    gpointer params, GstBuffer * buffer)

{

  GstVideoDSCVerificationMeta *dsc_meta = (GstVideoDSCVerificationMeta *) meta;

  GstVideoDSCVerificationMetaParams *p =

      (GstVideoDSCVerificationMetaParams *) params;

  gst_h274_dsc_verification_copy (&dsc_meta->dsc_verification,

      p->dsc_verification);

  return TRUE;

}

static void

gst_video_dsc_verification_meta_free (GstMeta * meta, GstBuffer * buffer)

{

  GstVideoDSCVerificationMeta *dsc_meta = (GstVideoDSCVerificationMeta *) meta;

  gst_h274_dsc_verification_free (&dsc_meta->dsc_verification);

}

const GstMetaInfo *

gst_video_dsc_verification_meta_get_info (void)

{

  static const GstMetaInfo *info = NULL;

  if (g_once_init_enter ((GstMetaInfo **) & info)) {

    const GstMetaInfo *meta =

        gst_meta_register (GST_VIDEO_DSC_VERIFICATION_META_API_TYPE,

        "GstVideoDSCVerificationMeta",

        sizeof (GstVideoDSCVerificationMeta),

        gst_video_dsc_verification_meta_init,

        gst_video_dsc_verification_meta_free,

        gst_video_dsc_verification_meta_transform);

    g_once_init_leave ((GstMetaInfo **) & info, (GstMetaInfo *) meta);

  }

  return info;

}

GstVideoDSCVerificationMeta *

gst_buffer_add_video_dsc_verification_meta (GstBuffer *

    buffer, const GstH274DigitallySignedContentVerification * dsc_verification)

{

  GstVideoDSCVerificationMeta *meta;

  GstVideoDSCVerificationMetaParams params = {

    .dsc_verification = dsc_verification,

  };

  g_return_val_if_fail (buffer != NULL, NULL);

  g_return_val_if_fail (dsc_verification != NULL, NULL);

  GST_DEBUG

      ("Adding DSC Verification Meta: id=%u, verification_substream_id=%u, "

      "signature_length_in_octets_minus1=%u",

      dsc_verification->id, dsc_verification->verification_substream_id,

      dsc_verification->signature_length_in_octets_minus1);

  if (dsc_verification->signature

      && dsc_verification->signature_length_in_octets_minus1 + 1 > 0) {

    for (guint i = 0;

        i < dsc_verification->signature_length_in_octets_minus1 + 1; i++) {

      guint8 byte = dsc_verification->signature[i];

      GST_DEBUG ("signature[%u] = %u (0x%02x)", i, byte, byte);

    }

  }

  params.dsc_verification = dsc_verification;

  meta = (GstVideoDSCVerificationMeta *)

      gst_buffer_add_meta (buffer,

      GST_VIDEO_DSC_VERIFICATION_META_INFO, &params);

  return meta;

}