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

package org.nd4j.linalg.api.ops.custom;

import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.val;
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.ndarray.INDArray;
import org.nd4j.linalg.api.ops.DynamicCustomOp;

import java.util.Arrays;
import java.util.List;

@Data
@NoArgsConstructor
public class Flatten extends DynamicCustomOp {
    private long order;

    public Flatten(char order, INDArray... inputs) {
        this.order = order;

        for (val in:inputs)
            inputArguments.add(in);

        iArguments.add(Long.valueOf((int) this.order));
    }

    public Flatten(INDArray output, INDArray... inputs) {
        this(output.ordering(), inputs);

        outputArguments.add(output);
    }

    public Flatten(SameDiff sameDiff, char order, SDVariable... inputs) {
        super(sameDiff, inputs);
        this.order = order;
        addIArgument(Long.valueOf((int) this.order));
    }

    public Flatten(SameDiff sd, SDVariable input, String order) {
        this(sd,order.charAt(0),input);
    }

    public Flatten(INDArray input, String order) {
        super(new INDArray[]{input},null);
        addIArgument(order.charAt(0));
    }

    public Flatten(SameDiff sd, SDVariable[] inputs, String order) {
        super(sd,inputs);
        addIArgument(order.charAt(0));
    }

    public Flatten(INDArray[] inputs, String order) {
        super(inputs,null);
        addIArgument(order.charAt(0));
    }

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

    @Override
    public List<SDVariable> doDiff(List<SDVariable> i_v) {
        return Arrays.asList(i_v.get(0).reshape(arg(0).shape()));
    }


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