/*
 *  ******************************************************************************
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 *  *
 *  * 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.
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 *  * SPDX-License-Identifier: Apache-2.0
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package org.nd4j.linalg.api.ops.impl.image;

import lombok.NonNull;
import org.nd4j.autodiff.samediff.SDVariable;
import org.nd4j.autodiff.samediff.SameDiff;
import org.nd4j.imports.NoOpNameFoundException;
import org.nd4j.linalg.api.buffer.DataType;
import org.nd4j.linalg.api.ndarray.INDArray;
import org.nd4j.linalg.api.ops.DynamicCustomOp;
import org.nd4j.linalg.api.ops.Op;

import java.util.Collections;
import java.util.List;

public class NonMaxSuppression extends DynamicCustomOp {

    public NonMaxSuppression() {}

    public NonMaxSuppression(SameDiff sameDiff, @NonNull SDVariable boxes, @NonNull SDVariable scores, @NonNull SDVariable maxOutSize,
                             @NonNull SDVariable iouThreshold, @NonNull SDVariable scoreThreshold) {
        super(null, sameDiff, new SDVariable[]{boxes, scores, maxOutSize, iouThreshold, scoreThreshold}, false);
    }

    public NonMaxSuppression(SameDiff sameDiff, SDVariable boxes, SDVariable scores, int maxOutSize,
                            double iouThreshold, double scoreThreshold) {
        super(null, sameDiff, new SDVariable[]{boxes, scores}, false);
        addIArgument(maxOutSize);
        addTArgument(iouThreshold, scoreThreshold);
    }

    public NonMaxSuppression(INDArray boxes, INDArray scores, int maxOutSize, double iouThreshold, double scoreThreshold) {
        addInputArgument(boxes,scores);
        addIArgument(maxOutSize);
        addTArgument(iouThreshold, scoreThreshold);
    }

    @Override
    public String onnxName() {
        throw new NoOpNameFoundException("No onnx name found for shape " + opName());
    }

    @Override
    public String tensorflowName() {
        return "NonMaxSuppression";
    }

    @Override
    public String[] tensorflowNames() {
        return new String[]{"NonMaxSuppression", "NonMaxSuppressionV2"};
    }

    @Override
    public String opName() {
        return "non_max_suppression";
    }

    @Override
    public Op.Type opType() {
        return Op.Type.CUSTOM;
    }

    @Override
    public List<SDVariable> doDiff(List<SDVariable> i_v) {
        return Collections.singletonList(sameDiff.zerosLike(arg()));
    }

    @Override
    public List<DataType> calculateOutputDataTypes(List<DataType> inputDataTypes){
        //Always 1D integer tensor (indices)
        return Collections.singletonList(DataType.INT);
    }
}
