/*******************************************************************************
 * Copyright (c) 2015-2018 Skymind, Inc.
 *
 * 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.
 *
 * 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 Created by raver119 on 24.11.17.
// @author Yurii Shyrma (iuriish@yahoo.com)
//

#include <op_boilerplate.h>
#if NOT_EXCLUDED(OP_scatter_sub)

#include <ops/declarable/CustomOperations.h>
#include <ops/declarable/generic/helpers/ScatterHelper.h>

namespace nd4j {
    namespace ops {
        OP_IMPL(scatter_sub, 3, 1, true) {
            auto input = INPUT_VARIABLE(0);
            auto indices = INPUT_VARIABLE(1);
            auto updates = INPUT_VARIABLE(2);

            auto output = OUTPUT_VARIABLE(0);

            const bool lock = block.getBArguments()->empty() ? false : B_ARG(0);

            const int inRank  = input->rankOf();
            const int indRank = indices->rankOf();
            const int updRank = updates->rankOf();
    
            REQUIRE_TRUE(inRank > 0, 0, "SCATTER_SUB OP: input should not be scalar !");
    
            if(inRank == 1) {
                REQUIRE_TRUE(indices->isSameShape(updates), 0, "SCATTER_SUB OP: when input array has rank = 1 then indices and updates must have the same shapes, but got %s and %s correspondingly !", ShapeUtils::shapeAsString(indices).c_str(), ShapeUtils::shapeAsString(updates).c_str());
            }
            else if (inRank == updRank && indices->isVector()) {

                std::vector<Nd4jLong> updShape = updates->getShapeAsVector();
                std::vector<Nd4jLong> inShape  = input->getShapeAsVector();
                std::vector<Nd4jLong> expectedUpdShape = {indices->lengthOf()}; 
                expectedUpdShape.insert(expectedUpdShape.end(), inShape.begin()+1, inShape.end());
        
                REQUIRE_TRUE(expectedUpdShape == updShape, 0, "SCATTER_SUB OP: wrong shape of updates array, expected is %s, but got %s instead !", ShapeUtils::shapeAsString(expectedUpdShape).c_str(), ShapeUtils::shapeAsString(updShape).c_str());
            }

            else {
        
                REQUIRE_TRUE(updRank == indRank + inRank - 1, 0, "SCATTER_SUB OP: wrong rank of updates array, expected is %i, but got %i instead !", indRank + inRank - 1 , updRank);
                
                std::vector<Nd4jLong> updShape = updates->getShapeAsVector();
                std::vector<Nd4jLong> inShape  = input->getShapeAsVector();
                std::vector<Nd4jLong> expectedUpdShape = indices->getShapeAsVector();        
                expectedUpdShape.insert(expectedUpdShape.end(), inShape.begin()+1, inShape.end());
        
                REQUIRE_TRUE(expectedUpdShape == updShape, 0, "SCATTER_SUB OP: wrong shape of updates array, expected is %s, but got %s instead !", ShapeUtils::shapeAsString(expectedUpdShape).c_str(), ShapeUtils::shapeAsString(updShape).c_str());
            }

            if (!block.isInplace())
                output->assign(input);

            // ScatterHelper<T>::template scatterApply<simdOps::Subtract<T>>(output, indices, updates);        
            helpers::scatter(block.launchContext(), pairwise::Subtract, *indices, *updates, *output, lock);

            return Status::OK();
        }
        DECLARE_SYN(ScatterSub, scatter_sub);

        DECLARE_TYPES(scatter_sub) {
            getOpDescriptor()
            ->setAllowedInputTypes(0, {ALL_INTS, ALL_FLOATS})
            ->setAllowedInputTypes(1, {ALL_INTS})
            ->setAllowedInputTypes(2, {ALL_INTS, ALL_FLOATS})
            ->setAllowedOutputTypes({ALL_INTS, ALL_FLOATS});
        }
    }
}

#endif