#include <boost/serialization/export.hpp>

#include "NeuronLogistic.h"
#include "NeuronSerialization.h"
#include "NeuronLogisticSerialization.h"

BOOST_CLASS_EXPORT_IMPLEMENT(lib4neuro::NeuronLogistic);
BOOST_CLASS_EXPORT_IMPLEMENT(lib4neuro::NeuronLogistic_d1);
BOOST_CLASS_EXPORT_IMPLEMENT(lib4neuro::NeuronLogistic_d2);

namespace lib4neuro {

    NeuronLogistic_d2::NeuronLogistic_d2() {}

    double NeuronLogistic_d2::activate(double x,
                                       double b) {
        //(e^(b + x) (e^b - e^x))/(e^b + e^x)^3

        double ex    = std::pow(lib4neuro::E,
                                x);
        double eb    = std::pow(E,
                                b);
        double denom = (eb + ex);

        return (eb * ex * (eb - ex)) / (denom * denom * denom);
    }

    double NeuronLogistic_d2::activation_function_eval_derivative_bias(double x,
                                                                       double b) {
        //-(e^(b + x) (-4 e^(b + x) + e^(2 b) + e^(2 x)))/(e^b + e^x)^4

        double eb    = std::pow(E,
                                b);
        double ex    = std::pow(E,
                                x);
        double ebex  = eb * ex;
        double denom = (eb + ex);

        return -(ebex * (-4 * ebex + eb * eb + ex * ex)) / (denom * denom * denom * denom);
    }

    double NeuronLogistic_d2::activation_function_eval_derivative(double x,
                                                                  double b) {
        //(e^(b + x) (-4 e^(b + x) + e^(2 b) + e^(2 x)))/(e^b + e^x)^4
        return -this->activation_function_eval_derivative_bias(x,
                                                               b);
    }

    NeuronLogistic* NeuronLogistic_d2::get_derivative() {
        //TODO maybe not the best way
        return nullptr;
    }

    NeuronLogistic_d1::NeuronLogistic_d1() {}


    double NeuronLogistic_d1::activate(double x,
                                       double b) {
        //e^(b - x)/(e^(b - x) + 1)^2

        double ex    = std::pow(E,
                                x);
        double eb    = std::pow(E,
                                b);
        double d     = (eb / ex);
        double denom = (d + 1);

        return d / (denom * denom);
    }

    double NeuronLogistic_d1::activation_function_eval_derivative_bias(double x,
                                                                       double b) {
        //(e^(b + x) (e^x - e^b))/(e^b + e^x)^3

        double ex    = std::pow(E,
                                x);
        double eb    = std::pow(E,
                                b);
        double denom = (eb + ex);

        return (eb * ex * (ex - eb)) / (denom * denom * denom);
    }

    double NeuronLogistic_d1::activation_function_eval_derivative(double x,
                                                                  double b) {
        //(e^(b + x) (e^b - e^x))/(e^b + e^x)^3
        return -this->activation_function_eval_derivative_bias(x,
                                                               b);
    }

    NeuronLogistic* NeuronLogistic_d1::get_derivative() {
        //(e^(b + x) (e^b - e^x))/(e^b + e^x)^3
        NeuronLogistic_d2* output = nullptr;

        output = new NeuronLogistic_d2();

        return output;
    }

    NeuronLogistic::NeuronLogistic() {}

    double NeuronLogistic::activate(double x,
                                    double b) {
        //(1 + e^(-x + b))^(-1)

        double ex = std::pow(E,
                             b - x);

        this->activation_val = 1.0 / (1.0 + ex);
        return this->activation_val;
    }

    double NeuronLogistic::activation_function_eval_derivative_bias(double x,
                                                                    double b) {
        double ex    = std::pow(E,
                                b - x);
        double denom = (ex + 1);
        double res   = -ex / (denom * denom);

        return res;
    }


    double NeuronLogistic::activation_function_eval_derivative(double x,
                                                               double b) {
        //e^(b - x)/(e^(b - x) + 1)^2
        return -this->activation_function_eval_derivative_bias(x,
                                                               b);

    }

    NeuronLogistic* NeuronLogistic::get_derivative() {

        NeuronLogistic_d1* output = nullptr;
        output = new NeuronLogistic_d1();

        return output;
    }

}