using System;

using System.Collections.Generic;

using System.Text;

using Tensorflow.Operations.Activation;

using static Tensorflow.Binding;

namespace Tensorflow.Keras

{

public class Activations

{

private static Dictionary<string, Activation> _nameActivationMap;

private static Dictionary<Activation, string> _activationNameMap;

private static Activation _linear = (features, name) => features;

private static Activation _relu = (features, name)

=> tf.Context.ExecuteOp("Relu", name, new ExecuteOpArgs(features));

private static Activation _sigmoid = (features, name)

=> tf.Context.ExecuteOp("Sigmoid", name, new ExecuteOpArgs(features));

private static Activation _softmax = (features, name)

=> tf.Context.ExecuteOp("Softmax", name, new ExecuteOpArgs(features));

private static Activation _tanh = (features, name)

=> tf.Context.ExecuteOp("Tanh", name, new ExecuteOpArgs(features));

/// <summary>

/// Register the name-activation mapping in this static class.

/// </summary>

/// <param name="name"></param>

/// <param name="Activation"></param>

private static void RegisterActivation(string name, Activation activation)

{

_nameActivationMap[name] = activation;

_activationNameMap[activation] = name;

}

static Activations()

{

_nameActivationMap = new Dictionary<string, Activation>();

_activationNameMap= new Dictionary<Activation, string>();

RegisterActivation("relu", _relu);

RegisterActivation("linear", _linear);

RegisterActivation("sigmoid", _sigmoid);

RegisterActivation("softmax", _softmax);

RegisterActivation("tanh", _tanh);

}

public Activation Linear => _linear;

public Activation Relu => _relu;

public Activation Sigmoid => _sigmoid;

public Activation Softmax => _softmax;

public Activation Tanh => _tanh;

public static Activation GetActivationByName(string name)

{

if (!_nameActivationMap.TryGetValue(name, out var res))

{

throw new Exception($"Activation {name} not found");

}

else

{

return res;

}

}

public static string GetNameByActivation(Activation activation)

{

if(!_activationNameMap.TryGetValue(activation, out var name))

{

throw new Exception($"Activation {activation} not found");

}

else

{

return name;

}

}

}

}