/*
 * 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
 */

static int FUNC(filler_payload)(CodedBitstreamContext *ctx, RWContext *rw,
  SEIRawFillerPayload *current, SEIMessageState *state) {
  int err, i;

  HEADER("Filler Payload");

#ifdef READ
  current->payload_size = state->payload_size;
#endif

  for(i = 0; i < current->payload_size; i++)
    fixed(8, ff_byte, 0xff);

  return 0;
}

static int FUNC(user_data_registered)(CodedBitstreamContext *ctx, RWContext *rw,
  SEIRawUserDataRegistered *current, SEIMessageState *state) {
  int err, i, j;

  HEADER("User Data Registered ITU-T T.35");

  u(8, itu_t_t35_country_code, 0x00, 0xff);
  if(current->itu_t_t35_country_code != 0xff)
    i = 1;
  else {
    u(8, itu_t_t35_country_code_extension_byte, 0x00, 0xff);
    i = 2;
  }

#ifdef READ
  if(state->payload_size < i) {
    av_log(ctx->log_ctx, AV_LOG_ERROR,
      "Invalid SEI user data registered payload.\n");
    return AVERROR_INVALIDDATA;
  }
  current->data_length = state->payload_size - i;
#endif

  allocate(current->data, current->data_length);
  for(j = 0; j < current->data_length; j++)
    xu(8, itu_t_t35_payload_byte[], current->data[j], 0x00, 0xff, 1, i + j);

  return 0;
}

static int FUNC(user_data_unregistered)(CodedBitstreamContext *ctx, RWContext *rw,
  SEIRawUserDataUnregistered *current, SEIMessageState *state) {
  int err, i;

  HEADER("User Data Unregistered");

#ifdef READ
  if(state->payload_size < 16) {
    av_log(ctx->log_ctx, AV_LOG_ERROR,
      "Invalid SEI user data unregistered payload.\n");
    return AVERROR_INVALIDDATA;
  }
  current->data_length = state->payload_size - 16;
#endif

  for(i = 0; i < 16; i++)
    us(8, uuid_iso_iec_11578[i], 0x00, 0xff, 1, i);

  allocate(current->data, current->data_length);

  for(i = 0; i < current->data_length; i++)
    xu(8, user_data_payload_byte[i], current->data[i], 0x00, 0xff, 1, i);

  return 0;
}

static int FUNC(mastering_display_colour_volume)(CodedBitstreamContext *ctx, RWContext *rw,
  SEIRawMasteringDisplayColourVolume *current, SEIMessageState *state) {
  int err, c;

  HEADER("Mastering Display Colour Volume");

  for(c = 0; c < 3; c++) {
    ubs(16, display_primaries_x[c], 1, c);
    ubs(16, display_primaries_y[c], 1, c);
  }

  ub(16, white_point_x);
  ub(16, white_point_y);

  ub(32, max_display_mastering_luminance);
  ub(32, min_display_mastering_luminance);

  return 0;
}

static int FUNC(content_light_level_info)(CodedBitstreamContext *ctx, RWContext *rw,
  SEIRawContentLightLevelInfo *current, SEIMessageState *state) {
  int err;

  HEADER("Content Light Level Information");

  ub(16, max_content_light_level);
  ub(16, max_pic_average_light_level);

  return 0;
}

static int FUNC(alternative_transfer_characteristics)(CodedBitstreamContext *ctx, RWContext *rw,
  SEIRawAlternativeTransferCharacteristics *current,
  SEIMessageState *state) {
  int err;

  HEADER("Alternative Transfer Characteristics");

  ub(8, preferred_transfer_characteristics);

  return 0;
}

static int FUNC(message)(CodedBitstreamContext *ctx, RWContext *rw,
  SEIRawMessage *current) {
  const SEIMessageTypeDescriptor *desc;
  int err, i;

  desc = ff_cbs_sei_find_type(ctx, current->payload_type);
  if(desc) {
    SEIMessageState state = {
      .payload_type      = current->payload_type,
      .payload_size      = current->payload_size,
      .extension_present = current->extension_bit_length > 0,
    };
    int start_position, current_position, bits_written;

#ifdef READ
    CHECK(ff_cbs_sei_alloc_message_payload(current, desc));
#endif

    start_position = bit_position(rw);

    CHECK(desc->READWRITE(ctx, rw, current->payload, &state));

    current_position = bit_position(rw);
    bits_written     = current_position - start_position;

    if(byte_alignment(rw) || state.extension_present ||
       bits_written < 8 * current->payload_size) {
      size_t bits_left;

#ifdef READ
      GetBitContext tmp = *rw;
      int trailing_bits, trailing_zero_bits;

      bits_left = 8 * current->payload_size - bits_written;
      if(bits_left > 8)
        skip_bits_long(&tmp, bits_left - 8);
      trailing_bits = get_bits(&tmp, FFMIN(bits_left, 8));
      if(trailing_bits == 0) {
        // The trailing bits must contain a bit_equal_to_one, so
        // they can't all be zero.
        return AVERROR_INVALIDDATA;
      }
      trailing_zero_bits = ff_ctz(trailing_bits);
      current->extension_bit_length =
        bits_left - 1 - trailing_zero_bits;
#endif

      if(current->extension_bit_length > 0) {
        allocate(current->extension_data,
          (current->extension_bit_length + 7) / 8);

        bits_left = current->extension_bit_length;
        for(i = 0; bits_left > 0; i++) {
          int length = FFMIN(bits_left, 8);
          xu(length, reserved_payload_extension_data,
            current->extension_data[i],
            0, MAX_UINT_BITS(length), 0);
          bits_left -= length;
        }
      }

      fixed(1, bit_equal_to_one, 1);
      while(byte_alignment(rw))
        fixed(1, bit_equal_to_zero, 0);
    }

#ifdef WRITE
    current->payload_size = (put_bits_count(rw) - start_position) / 8;
#endif
  }
  else {
    uint8_t *data;

    allocate(current->payload, current->payload_size);
    data = current->payload;

    for(i = 0; i < current->payload_size; i++)
      xu(8, payload_byte[i], data[i], 0, 255, 1, i);
  }

  return 0;
}

static int FUNC(message_list)(CodedBitstreamContext *ctx, RWContext *rw,
  SEIRawMessageList *current, int prefix) {
  SEIRawMessage *message;
  int err, k;

#ifdef READ
  for(k = 0;; k++) {
    uint32_t payload_type = 0;
    uint32_t payload_size = 0;
    uint32_t tmp;
    GetBitContext payload_gbc;

    while(show_bits(rw, 8) == 0xff) {
      fixed(8, ff_byte, 0xff);
      payload_type += 255;
    }
    xu(8, last_payload_type_byte, tmp, 0, 254, 0);
    payload_type += tmp;

    while(show_bits(rw, 8) == 0xff) {
      fixed(8, ff_byte, 0xff);
      payload_size += 255;
    }
    xu(8, last_payload_size_byte, tmp, 0, 254, 0);
    payload_size += tmp;

    // There must be space remaining for both the payload and
    // the trailing bits on the SEI NAL unit.
    if(payload_size + 1 > get_bits_left(rw) / 8) {
      av_log(ctx->log_ctx, AV_LOG_ERROR,
        "Invalid SEI message: payload_size too large "
        "(%" PRIu32 " bytes).\n",
        payload_size);
      return AVERROR_INVALIDDATA;
    }
    CHECK(init_get_bits(&payload_gbc, rw->buffer,
      get_bits_count(rw) + 8 * payload_size));
    skip_bits_long(&payload_gbc, get_bits_count(rw));

    CHECK(ff_cbs_sei_list_add(current));
    message = &current->messages[k];

    message->payload_type = payload_type;
    message->payload_size = payload_size;

    CHECK(FUNC(message)(ctx, &payload_gbc, message));

    skip_bits_long(rw, 8 * payload_size);

    if(!cbs_h2645_read_more_rbsp_data(rw))
      break;
  }
#else
  for(k = 0; k < current->nb_messages; k++) {
    PutBitContext start_state;
    uint32_t tmp;
    int trace, i;

    message = &current->messages[k];

    // We write the payload twice in order to find the size.  Trace
    // output is switched off for the first write.
    trace             = ctx->trace_enable;
    ctx->trace_enable = 0;

    start_state = *rw;
    for(i = 0; i < 2; i++) {
      *rw = start_state;

      tmp = message->payload_type;
      while(tmp >= 255) {
        fixed(8, ff_byte, 0xff);
        tmp -= 255;
      }
      xu(8, last_payload_type_byte, tmp, 0, 254, 0);

      tmp = message->payload_size;
      while(tmp >= 255) {
        fixed(8, ff_byte, 0xff);
        tmp -= 255;
      }
      xu(8, last_payload_size_byte, tmp, 0, 254, 0);

      err               = FUNC(message)(ctx, rw, message);
      ctx->trace_enable = trace;
      if(err < 0)
        return err;
    }
  }
#endif

  return 0;
}