#include "headers/animation.hpp"

namespace asloengine
{

    Animation::Animation(Function _function, float _start_value, float _end_value, float _duration)
    {

        reset(_function, _start_value, _end_value, _duration);

    }

    void Animation::reset(Function _function, float _start_value, float _end_value, float _duration)
    {

        function = _function;
        start_value = _start_value;
        current_value = _start_value;
        end_value = _end_value;
        time = 0;
        duration = _duration;        

    }

    float Animation::animate(float delta_time)
    {

        time += delta_time;

        if (time > duration)
        {
            time = duration;
        }

        switch (function)
        {

            case LINEAR:
                return calculate_linear();
            
            case EASE_IN:
                return calculate_ease_in();
            
            case EASE_OUT:
                return calculate_ease_out();
            
            case EASE_IN_OUT:
                return calculate_ease_in_out();

        }

        return 0;

    }

    float Animation::calculate_linear()
    {

        float value_difference = end_value - start_value;
        float progress = time / duration;

        return start_value + value_difference * progress;

    }
    
    float Animation::calculate_ease_in()
    {

        // TO-DO
        return 0;

    }

    float Animation::calculate_ease_out()
    {

        // TO-DO
        return 0;

    }

    float Animation::calculate_ease_in_out()
    {

        float value_difference = end_value - start_value;
        float progress = time / duration;
        
        progress = pow(progress, 2) / (pow(progress, 2) + pow((1 - progress), 2));
        
        return (start_value + value_difference * progress);
        
    }

}