// Copyright 2016 The Draco Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#include "draco/compression/attributes/sequential_attribute_decoder.h"

namespace draco {

SequentialAttributeDecoder::SequentialAttributeDecoder()
    : decoder_(nullptr), attribute_(nullptr), attribute_id_(-1) {}

bool SequentialAttributeDecoder::Init(PointCloudDecoder *decoder,
                                      int attribute_id) {
  decoder_ = decoder;
  attribute_ = decoder->point_cloud()->attribute(attribute_id);
  attribute_id_ = attribute_id;
  return true;
}

bool SequentialAttributeDecoder::InitializeStandalone(
    PointAttribute *attribute) {
  attribute_ = attribute;
  attribute_id_ = -1;
  return true;
}

bool SequentialAttributeDecoder::DecodePortableAttribute(
    const std::vector<PointIndex> &point_ids, DecoderBuffer *in_buffer) {
  if (attribute_->num_components() <= 0 || !attribute_->Reset(point_ids.size()))
    return false;
  if (!DecodeValues(point_ids, in_buffer))
    return false;
  return true;
}

bool SequentialAttributeDecoder::DecodeDataNeededByPortableTransform(
    const std::vector<PointIndex> &point_ids, DecoderBuffer *in_buffer) {
  // Default implementation does not apply any transform.
  return true;
}

bool SequentialAttributeDecoder::TransformAttributeToOriginalFormat(
    const std::vector<PointIndex> &point_ids) {
  // Default implementation does not apply any transform.
  return true;
}

const PointAttribute *SequentialAttributeDecoder::GetPortableAttribute() {
  // If needed, copy point to attribute value index mapping from the final
  // attribute to the portable attribute.
  if (!attribute_->is_mapping_identity() && portable_attribute_ &&
      portable_attribute_->is_mapping_identity()) {
    portable_attribute_->SetExplicitMapping(attribute_->indices_map_size());
    for (PointIndex i(0);
         i < static_cast<uint32_t>(attribute_->indices_map_size()); ++i) {
      portable_attribute_->SetPointMapEntry(i, attribute_->mapped_index(i));
    }
  }
  return portable_attribute_.get();
}

bool SequentialAttributeDecoder::InitPredictionScheme(
    PredictionSchemeInterface *ps) {
  for (int i = 0; i < ps->GetNumParentAttributes(); ++i) {
    const int att_id = decoder_->point_cloud()->GetNamedAttributeId(
        ps->GetParentAttributeType(i));
    if (att_id == -1)
      return false;  // Requested attribute does not exist.
#ifdef DRACO_BACKWARDS_COMPATIBILITY_SUPPORTED
    if (decoder_->bitstream_version() < DRACO_BITSTREAM_VERSION(2, 0)) {
      if (!ps->SetParentAttribute(decoder_->point_cloud()->attribute(att_id))) {
        return false;
      }
    } else
#endif
    {
      const PointAttribute *const pa = decoder_->GetPortableAttribute(att_id);
      if (pa == nullptr || !ps->SetParentAttribute(pa)) {
        return false;
      }
    }
  }
  return true;
}

bool SequentialAttributeDecoder::DecodeValues(
    const std::vector<PointIndex> &point_ids, DecoderBuffer *in_buffer) {
  const int32_t num_values = static_cast<uint32_t>(point_ids.size());
  const int entry_size = static_cast<int>(attribute_->byte_stride());
  std::unique_ptr<uint8_t[]> value_data_ptr(new uint8_t[entry_size]);
  uint8_t *const value_data = value_data_ptr.get();
  int out_byte_pos = 0;
  // Decode raw attribute values in their original format.
  for (int i = 0; i < num_values; ++i) {
    if (!in_buffer->Decode(value_data, entry_size))
      return false;
    attribute_->buffer()->Write(out_byte_pos, value_data, entry_size);
    out_byte_pos += entry_size;
  }
  return true;
}

}  // namespace draco