Units.h

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/* Copyright (c) 2023 Skyward Experimental Rocketry
 * Author: Davide Basso
 *
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#pragma once
 
#include <utils/Debug.h>
 
#include <ostream>
#include <ratio>
#include <typeinfo>
 
namespace Boardcore
{
namespace Units
{
 
enum class UnitKind
{
    Angle,
    Length,
    Pressure,
    Time,
    Speed,
    Acceleration,
    Frequency,
};
 
template <UnitKind Kind, class Ratio = std::ratio<1>>
class Unit
{
public:
    constexpr explicit Unit(float val) : _value(val) {}
 
    template <UnitKind FromKind, class FromRatio>
    constexpr explicit Unit(Unit<FromKind, FromRatio> const& from)
        : _value(from.template value<Ratio>())
    {
    }
 
    template <class TargetRatio = Ratio>
    constexpr float value() const
    {
        constexpr auto currentRatio =
            static_cast<float>(Ratio::num) / static_cast<float>(Ratio::den);
        constexpr auto targetRatio = static_cast<float>(TargetRatio::num) /
                                     static_cast<float>(TargetRatio::den);
 
        return _value * currentRatio / targetRatio;
    }
 
    template <UnitKind TargetKind, class TargetRatio = Ratio>
    constexpr operator Unit<TargetKind, TargetRatio>() const
    {
        return Unit<TargetKind, TargetRatio>(value<TargetRatio>());
    }
 
    template <UnitKind PKind, class PRatio>
    friend std::istream& operator>>(std::istream& is,
                                    Unit<PKind, PRatio>& unit);
 
private:
    float _value;
};
 
// Sum, Subtraction, Multiplication, Division
template <UnitKind Kind, class Ratio>
constexpr auto operator+(const Unit<Kind, Ratio>& lhs,
                         const Unit<Kind, Ratio>& rhs)
{
    return Unit<Kind, Ratio>(lhs.template value() + rhs.template value());
}
 
template <UnitKind Kind, class Ratio>
constexpr auto operator-(const Unit<Kind, Ratio>& lhs,
                         const Unit<Kind, Ratio>& rhs)
{
    return Unit<Kind, Ratio>(lhs.template value() - rhs.template value());
}
 
template <UnitKind Kind, class Ratio>
constexpr auto operator*(const Unit<Kind, Ratio>& lhs, float rhs)
{
    return Unit<Kind, Ratio>(lhs.template value() * rhs);
}
 
template <UnitKind Kind, class Ratio>
constexpr auto operator*(float lhs, const Unit<Kind, Ratio>& rhs)
{
    return Unit<Kind, Ratio>(lhs * rhs.template value());
}
 
template <UnitKind Kind, class Ratio>
constexpr auto operator/(const Unit<Kind, Ratio>& lhs, float rhs)
{
    return Unit<Kind, Ratio>(lhs.template value() / rhs);
}
 
template <UnitKind Kind, class Ratio>
constexpr auto operator/(float lhs, const Unit<Kind, Ratio>& rhs)
{
    return Unit<Kind, Ratio>(lhs / rhs.template value());
}
 
// Comparison operators
template <UnitKind Kind, class Ratio>
constexpr bool operator==(const Unit<Kind, Ratio>& lhs,
                          const Unit<Kind, Ratio>& rhs)
{
    return lhs.template value() == rhs.template value();
}
 
template <UnitKind Kind, class Ratio>
constexpr bool operator!=(const Unit<Kind, Ratio>& lhs,
                          const Unit<Kind, Ratio>& rhs)
{
    return lhs.template value() != rhs.template value();
}
 
template <UnitKind Kind, class Ratio>
constexpr bool operator<(const Unit<Kind, Ratio>& lhs,
                         const Unit<Kind, Ratio>& rhs)
{
    return lhs.template value() < rhs.template value();
}
 
template <UnitKind Kind, class Ratio>
constexpr bool operator>(const Unit<Kind, Ratio>& lhs,
                         const Unit<Kind, Ratio>& rhs)
{
    return lhs.template value() > rhs.template value();
}
 
template <UnitKind Kind, class Ratio>
constexpr bool operator<=(const Unit<Kind, Ratio>& lhs,
                          const Unit<Kind, Ratio>& rhs)
{
    return lhs.template value() <= rhs.template value();
}
 
template <UnitKind Kind, class Ratio>
constexpr bool operator>=(const Unit<Kind, Ratio>& lhs,
                          const Unit<Kind, Ratio>& rhs)
{
    return lhs.template value() >= rhs.template value();
}
 
// Direct assignment operators
template <UnitKind Kind, class Ratio>
constexpr Unit<Kind, Ratio>& operator+=(Unit<Kind, Ratio>& lhs,
                                        const Unit<Kind, Ratio>& rhs)
{
    lhs = lhs + rhs;
    return lhs;
}
 
template <UnitKind Kind, class Ratio>
constexpr Unit<Kind, Ratio>& operator-=(Unit<Kind, Ratio>& lhs,
                                        const Unit<Kind, Ratio>& rhs)
{
    lhs = lhs - rhs;
    return lhs;
}
 
template <UnitKind Kind, class Ratio>
constexpr Unit<Kind, Ratio>& operator*=(Unit<Kind, Ratio>& lhs, float rhs)
{
    lhs = lhs * rhs;
    return lhs;
}
 
template <UnitKind Kind, class Ratio>
constexpr Unit<Kind, Ratio>& operator/=(Unit<Kind, Ratio>& lhs, float rhs)
{
    lhs = lhs / rhs;
    return lhs;
}
 
// Unary operators
template <UnitKind Kind, class Ratio>
constexpr Unit<Kind, Ratio> operator+(const Unit<Kind, Ratio>& unit)
{
    return Unit<Kind, Ratio>(unit.template value());
}
 
template <UnitKind Kind, class Ratio>
constexpr Unit<Kind, Ratio> operator-(const Unit<Kind, Ratio>& unit)
{
    return Unit<Kind, Ratio>(-unit.template value());
}
 
template <UnitKind Kind, class Ratio>
constexpr bool operator!(const Unit<Kind, Ratio>& unit)
{
    return !unit.template value();
}
 
// Stream operators
template <UnitKind Kind, class Ratio>
std::ostream& operator<<(std::ostream& os, const Unit<Kind, Ratio>& unit)
{
    os << unit.template value();
    return os;
}
 
template <UnitKind Kind, class Ratio>
inline std::istream& operator>>(std::istream& is, Unit<Kind, Ratio>& unit)
{
    is >> unit._value;
    return is;
}
 
}  // namespace Units
}  // namespace Boardcore