/* ******************************************************************************
 *
 *
 * 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
 ******************************************************************************/

//
// Created by raver119 on 17.10.2017.
//
#include <array/DataTypeUtils.h>
#include <helpers/ConstantTadHelper.h>
#include <helpers/ShapeUtils.h>

#include <ops/declarable/LegacyStatsOp.h>
#include <ops/declarable/OpRegistrator.h>
#include <legacy/NativeOpExecutioner.h>

namespace sd {
namespace ops {
Status LegacyStatsOp::validateAndExecute(Context &block) {
  auto x = INPUT_VARIABLE(0);
  auto z = OUTPUT_VARIABLE(0);

  NDArray::prepareSpecialUse({z}, {x});

  // we assume that opNuk is either stored in block, or was provided via op constructor
  int opNum = block.opNum() < 0 ? this->_opNum : block.opNum();

  // bias goes as first argument, unlike all other reductions
  bool biasCorrected = false;
  if (block.getIArguments()->size() > 0) biasCorrected = INT_ARG(0) > 0;

  ExtraArguments extras(*block.getTArguments());
  PointersManager manager(block.launchContext(), "LegacyStatsOp");

  if (block.getIArguments()->size() == 1 ||
      (block.getIArguments()->size() == 2 && INT_ARG(1) == DataTypeUtils::max<int>())) {
    // scalar
    NativeOpExecutioner::execSummaryStatsScalar(block.launchContext(), opNum, x->buffer(), x->shapeInfo(),
                                                x->specialBuffer(), x->specialShapeInfo(),
                                                extras.argumentsAsT(z->dataType()), z->buffer(), z->shapeInfo(),
                                                z->specialBuffer(), z->specialShapeInfo(), biasCorrected);
  } else {
    // dimensions for TAD
    // we should skip first argument here, because it's addressing bias correction
    std::vector<LongType> dims(*block.getIArguments());
    for (size_t e = 0; e < dims.size(); e++)
      if (dims[e] < 0) dims[e] += x->rankOf();

    REQUIRE_TRUE(dims.size() > 0, 0, "Some dimensions requuired for reduction!");

    auto packX = ConstantTadHelper::getInstance().tadForDimensions(x->shapeInfo(), &dims);

    auto pTadShape = Environment::getInstance().isCPU()
                         ? packX->primaryShapeInfo()
                         : packX->specialShapeInfo();

    auto pTadOffsets = Environment::getInstance().isCPU()
                           ? packX->primaryOffsets()
                           : packX->specialOffsets();

    NativeOpExecutioner::execSummaryStats(block.launchContext(), opNum, x->buffer(), x->shapeInfo(), x->specialBuffer(),
                                          x->specialShapeInfo(), extras.argumentsAsT(z->dataType()), z->buffer(),
                                          z->shapeInfo(), z->specialBuffer(), z->specialShapeInfo(), dims.data(),
                                          (int)dims.size(), pTadShape, pTadOffsets, biasCorrected);
  }

  manager.synchronize();
  STORE_RESULT(*z);
  traceExecIfNeeded(block);

  return Status::OK;
}

LegacyStatsOp::LegacyStatsOp() : LegacyOp(1) {
  //
}

LegacyStatsOp::LegacyStatsOp(int opNum) : LegacyOp(1, opNum) {
  //
}

LegacyOp *LegacyStatsOp::clone() { return new LegacyStatsOp(this->_opNum); }

/**
 *   For all reductions rules are simple: either you return scalar, or you return reduced NDArray.
 *   It solely depends on input shape, and requested dimensions
 */
ShapeList *LegacyStatsOp::calculateOutputShape(ShapeList *inputShape, Context &block) {
  auto inShape = inputShape->at(0);

  LongType *newShape;
  if (block.getIArguments()->size() == 0 ||
      (block.getIArguments()->size() == 1 && INT_ARG(0) == DataTypeUtils::max<int>())) {
    // in this case we just return scalar
    ALLOCATE(newShape, block.getWorkspace(), shape::shapeInfoLength(2), sd::LongType);
    newShape[0] = 2;
    newShape[1] = 1;
    newShape[2] = 1;
    newShape[3] = 1;
    newShape[4] = 1;
    newShape[5] = 0;
    newShape[6] = 1;
    newShape[7] = 99;
  } else {
    sd::LongType *xShape2 = ShapeUtils::evalReduceShapeInfo('c', block.getIArguments(), inShape, false, true);
    return SHAPELIST(xShape2);
  }

  return SHAPELIST(CONSTANT(newShape));
}
}  // namespace ops
}  // namespace sd