/*
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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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package org.nd4j.linalg.api.ops.impl.layers.convolution;

import org.nd4j.autodiff.samediff.SDVariable;
import org.nd4j.autodiff.samediff.SameDiff;
import org.nd4j.common.base.Preconditions;
import org.nd4j.linalg.api.buffer.DataType;
import org.nd4j.linalg.api.ops.DynamicCustomOp;
import org.nd4j.linalg.api.ops.impl.layers.convolution.config.Conv2DConfig;
import org.nd4j.common.util.ArrayUtil;

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


public class Im2colBp extends DynamicCustomOp {

    protected Conv2DConfig conv2DConfig;

    public Im2colBp(SameDiff sameDiff, SDVariable i2cInput, SDVariable gradAtOutput, Conv2DConfig conv2DConfig) {
        super(null, sameDiff,new SDVariable[]{i2cInput, gradAtOutput});
        this.conv2DConfig = conv2DConfig;
        addArgs();
    }

    public Im2colBp(SameDiff sd, SDVariable input, Conv2DConfig config) {
        super(null, sd, new SDVariable[]{input});
        this.conv2DConfig = config;
        addArgs();
    }

    public Im2colBp() {}

    protected void addArgs() {
        addIArgument(conv2DConfig.getKH());
        addIArgument(conv2DConfig.getKW());
        addIArgument(conv2DConfig.getSH());
        addIArgument(conv2DConfig.getSW());
        addIArgument(conv2DConfig.getPH());
        addIArgument(conv2DConfig.getPW());
        addIArgument(conv2DConfig.getDH());
        addIArgument(conv2DConfig.getDW());
        addIArgument(conv2DConfig.getPaddingMode().index);
    }


    @Override
    public Map<String, Object> propertiesForFunction() {
        return conv2DConfig.toProperties();
    }

    @Override
    public String opName() {
        return "im2col_bp";
    }

    @Override
    public List<SDVariable> doDiff(List<SDVariable> f1) {
        throw new UnsupportedOperationException("Differentiation not supported for this op: " + getClass().getSimpleName());
    }

    @Override
    public List<DataType> calculateOutputDataTypes(List<DataType> inputDataTypes){
        Preconditions.checkState(inputDataTypes != null && inputDataTypes.size() == 2, "Expected 2 input data types for %s, got %s", getClass(), inputDataTypes);
        return Collections.singletonList(inputDataTypes.get(0));
    }
}
