/* ******************************************************************************
 *
 *
 * This program and the accompanying materials are made available under the
 * terms of the Apache License, Version 2.0 which is available at
 * https://www.apache.org/licenses/LICENSE-2.0.
 *
 *  See the NOTICE file distributed with this work for additional
 *  information regarding copyright ownership.
 * 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.
 *
 * SPDX-License-Identifier: Apache-2.0
 ******************************************************************************/

//
// @author Oleh Semeniv (oleg.semeniv@gmail.com)
//

#include <execution/Threads.h>
#include <helpers/ConstantTadHelper.h>
#include <ops/declarable/CustomOperations.h>
#include <ops/declarable/headers/images.h>
#if NOT_EXCLUDED(OP_rgb_to_grs)
namespace sd {
namespace ops {

CUSTOM_OP_IMPL(rgb_to_grs, 1, 1, false, 0, 0) {
  const auto input = INPUT_VARIABLE(0);
  auto output = OUTPUT_VARIABLE(0);

  const int inRank = input->rankOf();
  const int argSize = block.getIArguments()->size();
  const int dimC = argSize > 0 ? (INT_ARG(0) >= 0 ? INT_ARG(0) : INT_ARG(0) + inRank) : inRank - 1;

  REQUIRE_TRUE(inRank >= 1, 0, "RGBtoGrayScale: Fails to meet the inRank requirement: %i >= 1 ", inRank);
  if (argSize > 0) {
    REQUIRE_TRUE(dimC >= 0 && dimC < inRank, 0, "Index of the Channel dimension out of range: %i not in [%i,%i) ",
                 INT_ARG(0), -inRank, inRank);
  }
  REQUIRE_TRUE(input->sizeAt(dimC) == 3, 0,
               "RGBGrayScale: operation expects 3 channels (R, G, B) in last dimention, but received %i instead",
               input->sizeAt(dimC));

  helpers::transformRgbGrs(block.launchContext(), *input, *output, dimC);
  return Status::OK;
}

DECLARE_TYPES(rgb_to_grs) { getOpDescriptor()->setAllowedInputTypes({ALL_INTS, ALL_FLOATS})->setSameMode(true); }

DECLARE_SHAPE_FN(rgb_to_grs) {
  const auto input = INPUT_VARIABLE(0);
  const int inRank = input->rankOf();

  const int argSize = block.getIArguments()->size();
  const int dimC = argSize > 0 ? (INT_ARG(0) >= 0 ? INT_ARG(0) : INT_ARG(0) + inRank) : inRank - 1;

  REQUIRE_TRUE(inRank >= 1, 0, "RGBtoGrayScale: Fails to meet the inRank requirement: %i >= 1 ", inRank);
  if (argSize > 0) {
    REQUIRE_TRUE(dimC >= 0 && dimC < inRank, 0, "Index of the Channel dimension out of range: %i not in [%i,%i) ",
                 INT_ARG(0), -inRank, inRank);
  }
  REQUIRE_TRUE(input->sizeAt(dimC) == 3, 0,
               "RGBtoGrayScale: operation expects 3 channels (R, B, G) in last dimention, but received %i", dimC);

  auto* inputShapeVec = input->getShapeAsVector();
  (*inputShapeVec)[dimC] = 1;

  auto result = SHAPELIST(ConstantShapeHelper::getInstance().createShapeInfo(input->dataType(), input->ordering(), *inputShapeVec));
  delete inputShapeVec;
  return result;
}

}  // namespace ops
}  // namespace sd

#endif