#pragma once

#include "mcc_traits.h"
#include "utils.h"

constexpr double operator""_rads(long double val)  // angle in radians (no conversion)
{
    return val;
}

constexpr double operator""_degs(long double val)  // angle in degrees
{
    return val * std::numbers::pi / 180.0;
}

constexpr double operator""_dms(const char* s, size_t size)  // as a string "DEGREES:MINUTES:SECONDS"
{
    auto res = mcc::utils::parsAngleString(std::span{s, size});
    if (res.has_value()) {
        return res.value() * std::numbers::pi / 180.0;
    } else {
        throw std::invalid_argument("invalid sexagesimal representation");
    }
}

constexpr double operator""_hms(const char* s, size_t len)  // as a string "HOURS:MINUTES:SECONDS"
{
    auto res = mcc::utils::parsAngleString(std::span{s, len}, true);
    if (res.has_value()) {
        return res.value() * std::numbers::pi / 180.0;
    } else {
        throw std::invalid_argument("invalid sexagesimal representation");
    }
}


namespace mcc
{

/*  MCC-LIBRARY COORDINATES REPRESENTATION DEFINITIONS AND CLASS   */



// tags for MccAngle class construction

struct MccRadianTag {
};
struct MccDegreeTag {
};
static constexpr MccDegreeTag mcc_degrees{};
struct MccHMSTag {
};
static constexpr MccHMSTag mcc_hms{};


class MccAngle
{
protected:
    double _angleInRads{0.0};
    int _precision{2};

public:
    enum norm_kind_t {
        NORM_KIND_0_360,    // [0,360]
        NORM_KIND_0_180,    // [0,180]
        NORM_KIND_180_180,  // [-180,180]
        NORM_KIND_90_90,    // [-90,90]
    };

    MccAngle() = default;

    // by default angle is in radians
    MccAngle(std::convertible_to<double> auto const& val, const MccRadianTag = MccRadianTag{}) : _angleInRads(val) {}

    // construct angle in degrees, e.g.:
    //     auto ang = MccAngle{180.0, mcc_degrees};
    MccAngle(std::convertible_to<double> auto const& val, const MccDegreeTag)
    {
        _angleInRads = val * utils::deg2radCoeff;
    }

    // constuct angle from sexagesimal representation or floating-point number of degrees, e.g.:
    //     auto ang = MccAngle{"-12:34:56.789"}; // from degrees:minutes:seconds
    //     auto ang = MccAngle{"123.574698"}; // from degrees
    MccAngle(traits::mcc_input_char_range auto const& val)
    {
        auto res = utils::parsAngleString(val);
        if (res.has_value()) {
            _angleInRads = res.value() * utils::deg2radCoeff;
        } else {
            throw std::invalid_argument("invalid sexagesimal representation");
        }
    }

    // construct angle from sexagesimal representation or floating-point number of degrees, e.g.:
    //     auto ang = MccAngle{"01:23:45.6789", mcc_hms}; // from hours:minutes:seconds
    //     auto ang = MccAngle{"123.574698"}; // from degrees
    MccAngle(traits::mcc_input_char_range auto const& val, const MccHMSTag)
    {
        auto res = utils::parsAngleString(val, true);
        if (res.has_value()) {
            _angleInRads = res.value() * utils::deg2radCoeff;
        } else {
            throw std::invalid_argument("invalid sexagesimal representation");
        }
    }

    virtual ~MccAngle() = default;

    // normalize coordinate
    template <norm_kind_t KIND>
    MccAngle& normalize()
    {
        _angleInRads = std::fmod(_angleInRads, std::numbers::pi * 2.0);

        if constexpr (KIND == NORM_KIND_0_360) {
            if (_angleInRads < 0.0) {
                _angleInRads += 2.0 * std::numbers::pi;
            }
        } else if constexpr (KIND == NORM_KIND_0_180) {
            if (_angleInRads < -std::numbers::pi) {
                _angleInRads = 2.0 * std::numbers::pi + _angleInRads;
            } else if (_angleInRads < 0.0) {
                _angleInRads = -_angleInRads;
            }
        } else if constexpr (KIND == NORM_KIND_180_180) {
            if (_angleInRads > std::numbers::pi) {
                _angleInRads = 2.0 * std::numbers::pi - _angleInRads;
            } else if (_angleInRads < -std::numbers::pi) {
                _angleInRads += 2.0 * std::numbers::pi;
            }
        } else if constexpr (KIND == NORM_KIND_90_90) {
            if (_angleInRads >= 1.5 * std::numbers::pi) {
                _angleInRads = _angleInRads - 2.0 * std::numbers::pi;
            } else if (_angleInRads >= std::numbers::pi / 2.0) {
                _angleInRads = std::numbers::pi - _angleInRads;
            } else if (_angleInRads <= -1.5 * std::numbers::pi) {
                _angleInRads += 2.0 * std::numbers::pi;
            } else if (_angleInRads <= -std::numbers::pi / 2.0) {
                _angleInRads = -(std::numbers::pi + _angleInRads);
            }
        }

        return *this;
    }

    MccAngle& normalize()
    {
        return normalize<NORM_KIND_0_360>();
    }


    template <typename T>
    operator T() const
        requires std::is_arithmetic_v<T>
    {
        return _angleInRads;
    }

    operator double() const
    {
        return _angleInRads;
    }


    template <typename T>
    T degrees() const
    {
        return _angleInRads * 180.0 / std::numbers::pi;
    }

    double degrees() const
    {
        return degrees<double>();
    }

    template <traits::mcc_output_char_range T>
    T sexagesimal(bool hms, int prec = 2) const
    {
        return utils::rad2sxg(_angleInRads, hms, prec >= 0 ? prec : _precision);
    }

    std::string sexagesimal(bool hms, int prec = 2) const
    {
        return sexagesimal<std::string>(hms, prec);
    }


    // arithmetics

    template <typename SelfT, std::convertible_to<MccAngle> T>
    SelfT& operator+=(this SelfT& self, const T& v)
    {
        if constexpr (std::derived_from<T, MccAngle>) {
            static_assert(std::derived_from<SelfT, T>, "INCOMPATIBLE TYPES!");

            self._angleInRads += v._angleInRads;
        } else if constexpr (std::is_arithmetic_v<T>) {
            self._angleInRads += v;
        } else {
            self._angleInRads += MccAngle(v)._angleInRads;
        }

        return self;
    }

    template <typename SelfT, std::convertible_to<MccAngle> T>
    SelfT& operator-=(this SelfT& self, const T& v)
    {
        if constexpr (std::derived_from<T, MccAngle>) {
            static_assert(std::derived_from<SelfT, T>, "INCOMPATIBLE TYPES!");

            self._angleInRads -= v._angleInRads;
        } else if constexpr (std::is_arithmetic_v<T>) {
            self._angleInRads -= v;
        } else {
            self._angleInRads -= MccAngle(v)._angleInRads;
        }

        return self;
    }

    template <typename SelfT, typename T>
    SelfT& operator*=(this SelfT& self, const T& v)
        requires std::is_arithmetic_v<T>
    {
        self._angleInRads *= v;

        return self;
    }

    template <typename SelfT, typename T>
    SelfT& operator/=(this SelfT& self, const T& v)
        requires std::is_arithmetic_v<T>
    {
        self._angleInRads /= v;

        return self;
    }


    template <typename SelfT>
    SelfT& operator-(this SelfT& self)
    {
        self._angleInRads = -self._angleInRads;

        return self;
    }
};


// binary arithmetic operations

template <std::convertible_to<MccAngle> T1, std::convertible_to<MccAngle> T2>
auto operator+(const T1& v1, const T2& v2)
{
    static_assert(std::convertible_to<T1, T2> || std::convertible_to<T2, T1>, "INCOMPATIBLE TYPES!");

    using res_t = std::conditional_t<std::convertible_to<T1, T2>, T1, T2>;

    return res_t{(double)v1 + (double)v2};
}

template <std::convertible_to<MccAngle> T1, std::convertible_to<MccAngle> T2>
auto operator-(const T1& v1, const T2& v2)
{
    static_assert(std::convertible_to<T1, T2> || std::convertible_to<T2, T1>, "INCOMPATIBLE TYPES!");

    using res_t = std::conditional_t<std::convertible_to<T1, T2>, T1, T2>;

    return res_t{(double)v1 - (double)v2};
}


template <std::convertible_to<MccAngle> T1, std::convertible_to<MccAngle> T2>
auto operator*(const T1& v1, const T2& v2)
{
    if constexpr (std::is_arithmetic_v<T1>) {
        return v2 *= v1;
    } else if constexpr (std::is_arithmetic_v<T2>) {
        return v1 *= v2;
    } else {
        static_assert(false, "INCOMPATIBLE TYPES!");
    }
}

template <std::convertible_to<MccAngle> T1, typename T2>
auto operator/(const T1& v1, const T2& v2)
    requires std::is_arithmetic_v<T2>
{
    return v1 /= v2;
}


/*  */

class MccAngleRA_ICRS : public MccAngle
{
    using MccAngle::MccAngle;
};

class MccAngleDEC_ICRS : public MccAngle
{
    using MccAngle::MccAngle;
};

class MccAngleRA_APP : public MccAngle
{
    using MccAngle::MccAngle;
};

class MccAngleDEC_APP : public MccAngle
{
    using MccAngle::MccAngle;
};

class MccAngleHA : public MccAngle
{
    using MccAngle::MccAngle;
};

class MccAngleAZ : public MccAngle
{
    using MccAngle::MccAngle;
};

class MccAngleZD : public MccAngle
{
    using MccAngle::MccAngle;
};

class MccAngleALT : public MccAngle
{
    using MccAngle::MccAngle;
};


class MccAngleX : public MccAngle  // some co-longitude coordinate
{
    using MccAngle::MccAngle;
};

class MccAngleY : public MccAngle  // some co-latitude coordinate
{
    using MccAngle::MccAngle;
};



class MccAngleLAT : public MccAngle
{
    using MccAngle::MccAngle;
};

class MccAngleLON : public MccAngle
{
    using MccAngle::MccAngle;
};


enum class MccCoordPairKind : size_t {
    COORDS_KIND_GENERIC = traits::mcc_type_pair_hash<MccAngle, MccAngle>(),
    COORDS_KIND_RADEC_ICRS = traits::mcc_type_pair_hash<MccAngleRA_ICRS, MccAngleDEC_ICRS>(),
    COORDS_KIND_RADEC_APP = traits::mcc_type_pair_hash<MccAngleRA_APP, MccAngleDEC_APP>(),
    COORDS_KIND_HADEC = traits::mcc_type_pair_hash<MccAngleHA, MccAngleDEC_APP>(),
    COORDS_KIND_AZZD = traits::mcc_type_pair_hash<MccAngleAZ, MccAngleZD>(),
    COORDS_KIND_AZALT = traits::mcc_type_pair_hash<MccAngleAZ, MccAngleALT>(),
    COORDS_KIND_XY = traits::mcc_type_pair_hash<MccAngleX, MccAngleY>(),
    COORDS_KIND_LATLON = traits::mcc_type_pair_hash<MccAngleLAT, MccAngleLON>()
};

}  // namespace mcc