#ifndef units_hh_INCLUDED
#define units_hh_INCLUDED

#include "hash.hh"

#include <type_traits>

namespace Kakoune
{

template<typename RealType, typename ValueType = int>
class StronglyTypedNumber
{
public:
    [[gnu::always_inline]]
    explicit constexpr StronglyTypedNumber(ValueType value)
        : m_value(value)
    {
        static_assert(std::is_base_of<StronglyTypedNumber, RealType>::value,
                     "RealType is not derived from StronglyTypedNumber");
    }

    [[gnu::always_inline]]
    constexpr friend RealType operator+(RealType lhs, RealType rhs)
    { return RealType(lhs.m_value + rhs.m_value); }

    [[gnu::always_inline]]
    constexpr friend RealType operator-(RealType lhs, RealType rhs)
    { return RealType(lhs.m_value - rhs.m_value); }

    [[gnu::always_inline]]
    constexpr friend RealType operator*(RealType lhs, RealType rhs)
    { return RealType(lhs.m_value * rhs.m_value); }

    [[gnu::always_inline]]
    constexpr friend RealType operator/(RealType lhs, RealType rhs)
    { return RealType(lhs.m_value / rhs.m_value); }

    [[gnu::always_inline]]
    RealType& operator+=(RealType other)
    { m_value += other.m_value; return static_cast<RealType&>(*this); }

    [[gnu::always_inline]]
    RealType& operator-=(RealType other)
    { m_value -= other.m_value; return static_cast<RealType&>(*this); }

    [[gnu::always_inline]]
    RealType& operator*=(RealType other)
    { m_value *= other.m_value; return static_cast<RealType&>(*this); }

    [[gnu::always_inline]]
    RealType& operator/=(RealType other)
    { m_value /= other.m_value; return static_cast<RealType&>(*this); }

    [[gnu::always_inline]]
    RealType& operator++()
    { ++m_value; return static_cast<RealType&>(*this); }

    [[gnu::always_inline]]
    RealType& operator--()
    { --m_value; return static_cast<RealType&>(*this); }

    [[gnu::always_inline]]
    RealType operator++(int)
    { RealType backup(static_cast<RealType&>(*this)); ++m_value; return backup; }

    [[gnu::always_inline]]
    RealType operator--(int)
    { RealType backup(static_cast<RealType&>(*this)); --m_value; return backup; }

    [[gnu::always_inline]]
    constexpr RealType operator-() const { return RealType(-m_value); }

    [[gnu::always_inline]]
    constexpr friend RealType operator%(RealType lhs, RealType rhs)
    { return RealType(lhs.m_value % rhs.m_value); }

    [[gnu::always_inline]]
    RealType& operator%=(RealType other)
    { m_value %= other.m_value; return static_cast<RealType&>(*this); }

    [[gnu::always_inline]]
    constexpr friend bool operator==(RealType lhs, RealType rhs)
    { return lhs.m_value == rhs.m_value; }

    [[gnu::always_inline]]
    constexpr friend bool operator!=(RealType lhs, RealType rhs)
    { return lhs.m_value != rhs.m_value; }

    [[gnu::always_inline]]
    constexpr friend bool operator<(RealType lhs, RealType rhs)
    { return lhs.m_value < rhs.m_value; }

    [[gnu::always_inline]]
    constexpr friend bool operator<=(RealType lhs, RealType rhs)
    { return lhs.m_value <= rhs.m_value; }

    [[gnu::always_inline]]
    constexpr friend bool operator>(RealType lhs, RealType rhs)
    { return lhs.m_value > rhs.m_value; }

    [[gnu::always_inline]]
    constexpr friend bool operator>=(RealType lhs, RealType rhs)
    { return lhs.m_value >= rhs.m_value; }

    [[gnu::always_inline]]
    constexpr bool operator!() const
    { return not m_value; }

    [[gnu::always_inline]]
    explicit constexpr operator ValueType() const { return m_value; }
    [[gnu::always_inline]]
    explicit constexpr operator bool() const { return m_value; }

    friend size_t hash_value(RealType val) { return hash_value(val.m_value); }
    friend size_t abs(RealType val) { return val.m_value < ValueType(0) ? -val.m_value : val.m_value; }

private:
    ValueType m_value;
};

struct LineCount : public StronglyTypedNumber<LineCount, int>
{
    [[gnu::always_inline]]
    constexpr LineCount(int value = 0) : StronglyTypedNumber<LineCount>(value) {}
};

[[gnu::always_inline]]
inline constexpr LineCount operator"" _line(unsigned long long int value)
{
    return LineCount(value);
}

struct ByteCount : public StronglyTypedNumber<ByteCount, int>
{
    [[gnu::always_inline]]
    constexpr ByteCount(int value = 0) : StronglyTypedNumber<ByteCount>(value) {}
};

[[gnu::always_inline]]
inline constexpr ByteCount operator"" _byte(unsigned long long int value)
{
    return ByteCount(value);
}

struct CharCount : public StronglyTypedNumber<CharCount, int>
{
    [[gnu::always_inline]]
    constexpr CharCount(int value = 0) : StronglyTypedNumber<CharCount>(value) {}
};

[[gnu::always_inline]]
inline constexpr CharCount operator"" _char(unsigned long long int value)
{
    return CharCount(value);
}

}

#endif // units_hh_INCLUDED