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

package org.deeplearning4j.nn.modelimport.keras.layers.advanced.activations;

import org.deeplearning4j.nn.conf.inputs.InputType;
import org.deeplearning4j.nn.conf.layers.ActivationLayer;
import org.deeplearning4j.nn.modelimport.keras.KerasLayer;
import org.deeplearning4j.nn.modelimport.keras.exceptions.InvalidKerasConfigurationException;
import org.deeplearning4j.nn.modelimport.keras.exceptions.UnsupportedKerasConfigurationException;
import org.deeplearning4j.nn.modelimport.keras.utils.KerasLayerUtils;
import org.nd4j.linalg.activations.IActivation;
import org.nd4j.linalg.activations.impl.ActivationThresholdedReLU;

import java.util.Map;

/**
 * Imports ThresholdedReLU layer from Keras
 *
 * @author Max Pumperla
 */
public class KerasThresholdedReLU extends KerasLayer {


    /**
     * Constructor from parsed Keras layer configuration dictionary.
     *
     * @param layerConfig dictionary containing Keras layer configuration
     * @throws InvalidKerasConfigurationException Invalid Keras config
     * @throws UnsupportedKerasConfigurationException Unsupported Invalid Keras config
     */
    public KerasThresholdedReLU(Map<String, Object> layerConfig)
            throws InvalidKerasConfigurationException, UnsupportedKerasConfigurationException {
        this(layerConfig, true);
    }

    /**
     * Constructor from parsed Keras layer configuration dictionary.
     *
     * @param layerConfig           dictionary containing Keras layer configuration
     * @param enforceTrainingConfig whether to enforce training-related configuration options
     * @throws InvalidKerasConfigurationException Invalid Keras config
     * @throws UnsupportedKerasConfigurationException Invalid Keras config
     */
    public KerasThresholdedReLU(Map<String, Object> layerConfig, boolean enforceTrainingConfig)
            throws InvalidKerasConfigurationException, UnsupportedKerasConfigurationException {
        super(layerConfig, enforceTrainingConfig);
        Map<String, Object> innerConfig = KerasLayerUtils.getInnerLayerConfigFromConfig(layerConfig, conf);
        double theta = 1.0;
        String layerFieldThresholdTheta = "theta";
        if (innerConfig.containsKey(layerFieldThresholdTheta)) {
            theta = (double) innerConfig.get(layerFieldThresholdTheta);
        }
        IActivation thresholdedReLU = new ActivationThresholdedReLU(theta);
        this.layer = new ActivationLayer.Builder().name(this.layerName).activation(thresholdedReLU).build();
    }

    /**
     * Get layer output type.
     *
     * @param inputType Array of InputTypes
     * @return output type as InputType
     * @throws InvalidKerasConfigurationException Invalid Keras config
     */
    public InputType getOutputType(InputType... inputType) throws InvalidKerasConfigurationException {
        if (inputType.length > 1)
            throw new InvalidKerasConfigurationException(
                    "Keras Activation layer accepts only one input (received " + inputType.length + ")");
        return this.getActivationLayer().getOutputType(-1, inputType[0]);
    }

    /**
     * Get DL4J ActivationLayer.
     *
     * @return ActivationLayer
     */
    public ActivationLayer getActivationLayer() {
        return (ActivationLayer) this.layer;
    }

}
