/*****************************************************************************************
 *                                                                                       *
 * OpenSpace                                                                             *
 *                                                                                       *
 * Copyright (c) 2014-2024                                                               *
 *                                                                                       *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this  *
 * software and associated documentation files (the "Software"), to deal in the Software *
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 * permit persons to whom the Software is furnished to do so, subject to the following   *
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 * or substantial portions of the Software.                                              *
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 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,   *
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A         *
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 ****************************************************************************************/

#include <ghoul/misc/assert.h>
#include <ghoul/glm.h>

namespace openspace::interaction {

template <typename T, typename ScaleType>
DelayedVariable<T, ScaleType>::DelayedVariable(ScaleType scaleFactor, ScaleType friction)
    : _scaleFactor(std::move(scaleFactor))
    , _friction(friction)
{
    ghoul_assert(_friction >= ScaleType(0.0), "Friction must be positive");
}

template <typename T, typename ScaleType>
void DelayedVariable<T, ScaleType>::set(T value, double dt) {
    _targetValue = value;
    _currentValue = _currentValue + (_targetValue - _currentValue) *
        glm::min(_scaleFactor * dt, 1.0); // less or equal to 1.0 keeps it stable
}

template <typename T, typename ScaleType>
void DelayedVariable<T, ScaleType>::decelerate(double dt) {
    _currentValue = _currentValue + (- _currentValue) *
        glm::min(_scaleFactor * _friction * dt, 1.0);
        // less or equal to 1.0 keeps it stable
}

template <typename T, typename ScaleType>
void DelayedVariable<T, ScaleType>::setHard(T value) {
    _targetValue = value;
    _currentValue = value;
}

template <typename T, typename ScaleType>
void DelayedVariable<T, ScaleType>::setFriction(ScaleType friction) {
    _friction = friction;
    ghoul_assert(_friction >= ScaleType(0.0), "Friction must be positive");
}

template <typename T, typename ScaleType>
void DelayedVariable<T, ScaleType>::setScaleFactor(ScaleType scaleFactor) {
    _scaleFactor = scaleFactor;
}

template <typename T, typename ScaleType>
T DelayedVariable<T, ScaleType>::get() const {
    return _currentValue;
}

} // namespace openspace::interaction