/* ******************************************************************************
 *
 *
 * 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 raver119@gmail.com
//

#include <system/op_boilerplate.h>
#if NOT_EXCLUDED(OP_select)

#include <helpers/ShapeUtils.h>
#include <ops/declarable/CustomOperations.h>

namespace sd {
namespace ops {
CUSTOM_OP_IMPL(select, 3, 1, false, 0, 0) {
  auto cond = INPUT_VARIABLE(0);
  auto x = INPUT_VARIABLE(1);
  auto y = INPUT_VARIABLE(2);
  //TODO: for some reason y being empty
  //should not necessarily yield an empty result
  //the loss test I'm currently dealing with seems
  //to need to output a value yet it ends up being empty.
  //we need to figure out why
  if(x->isEmpty() || y->isEmpty() || cond->isEmpty()) {
    return Status::OK;
  }
  if (x->isScalar()) {
    REQUIRE_TRUE(cond->isScalar(), 0,
                 "Select: Condition should gave either equal shape to X/Y first dimension or to be scalar");

    auto z = OUTPUT_VARIABLE(0);

    if (y->isR()) {
#ifdef HAS_DOUBLE
      auto v = !cond->e<bool>(0) ? y->e<double>(0) : x->e<double>(0);
#elif defined(HAS_FLOAT32)
      auto v = !cond->e<bool>(0) ? y->e<float>(0) : x->e<float>(0);
#else
#error "No floating-point type available for select operation"
#endif
      z->p(0, v);
    } else {
      auto v = !cond->e<bool>(0) ? y->e<LongType>(0) : x->e<LongType>(0);
      z->p(0, v);
    }
  } else {
    bool same = cond->isSameShape(x);
    REQUIRE_TRUE(cond->isScalar() || cond->lengthOf() == x->sizeAt(0) || same, 0,
                 "Select: Condition should gave either equal shape to X/Y first dimension or to be scalar");
    if (same) {
      auto z = OUTPUT_VARIABLE(0);

      for (int e = 0; e < cond->lengthOf(); e++) {
        if (y->isR()) {
#ifdef HAS_DOUBLE
          auto r = !cond->e<bool>(e) ? y->e<double>(e) : x->e<double>(e);
#elif defined(HAS_FLOAT32)
          auto r = !cond->e<bool>(e) ? y->e<float>(e) : x->e<float>(e);
#else
#error "No floating-point type available for select operation"
#endif
          z->p(e, r);
        } else {
          auto r = !cond->e<bool>(e) ? y->e<LongType>(e) : x->e<LongType>(e);
          z->p(e, r);
        }
      }
    } else {
      REQUIRE_TRUE(cond->lengthOf() == x->sizeAt(0), 0,
                   "Condition length should be equal to the dim0 of x/y to act as TAD-mask, but got %d instead",
                   cond->lengthOf());

      auto z = OUTPUT_VARIABLE(0);
      std::vector<LongType> idxs;
      idxs.push_back(0);
      auto dims = ShapeUtils::evalDimsToExclude(x->rankOf() ,1,idxs.data());
      auto tadsX = x->allTensorsAlongDimension(*dims);
      auto tadsY = y->allTensorsAlongDimension(*dims);
      auto tadsZ = z->allTensorsAlongDimension(*dims);

      for (int e = 0; e < tadsX.size(); e++) {
        if (!cond->e<bool>(e)) {
          tadsZ.at(e)->assign(tadsY.at(e));
        } else {
          tadsZ.at(e)->assign(tadsX.at(e));
        }
      }

      delete dims;
    }
  }

  return Status::OK;
}

DECLARE_SHAPE_FN(select) {
  auto inShape = inputShape->at(1);
  return SHAPELIST(CONSTANT(inShape));
}

DECLARE_TYPES(select) {
  getOpDescriptor()
      ->setAllowedInputTypes(0, BOOL)
      ->setAllowedInputTypes(1, ANY)
      ->setAllowedInputTypes(2, ANY)
      ->setAllowedOutputTypes(1, INHERIT);
}
}  // namespace ops
}  // namespace sd

#endif