frames.hpp

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#pragma once
 
#include "ffi_core.hpp"
 
namespace siderust {
namespace frames {
 
// ============================================================================
// Frame Trait
// ============================================================================
 
template <typename F>
struct FrameTraits; // primary template — intentionally undefined
 
template <typename F, typename = void>
struct is_frame : std::false_type {};
 
template <typename F>
struct is_frame<F, std::void_t<decltype(FrameTraits<F>::ffi_id)>> : std::true_type {};
 
template <typename F>
inline constexpr bool is_frame_v = is_frame<F>::value;
 
// ============================================================================
// Frame Tag Definitions
// ============================================================================
 
struct ICRS {};
struct ICRF {};
struct EclipticMeanJ2000 {};
struct EclipticOfDate {};
struct EclipticTrueOfDate {};
struct EquatorialMeanJ2000 {};
struct EquatorialMeanOfDate {};
struct EquatorialTrueOfDate {};
struct Horizontal {};
struct Galactic {};
struct ECEF {};
struct ITRF {};
struct CIRS {};
struct GCRS {};
struct TIRS {};
struct EclipticMeanOfDate {};
 
// ============================================================================
// FrameTraits Specializations
// ============================================================================
 
#define SIDERUST_DEFINE_FRAME(Tag, EnumVal, Label)                 \
    template <>                                                    \
    struct FrameTraits<Tag> {                                      \
        static constexpr siderust_frame_t ffi_id = EnumVal;        \
        static constexpr const char*      name() { return Label; } \
    }
 
SIDERUST_DEFINE_FRAME(ICRS, SIDERUST_FRAME_T_ICRS, "ICRS");
SIDERUST_DEFINE_FRAME(ICRF, SIDERUST_FRAME_T_ICRF, "ICRF");
SIDERUST_DEFINE_FRAME(EclipticMeanJ2000, SIDERUST_FRAME_T_ECLIPTIC_MEAN_J2000, "EclipticMeanJ2000");
SIDERUST_DEFINE_FRAME(EclipticOfDate, SIDERUST_FRAME_T_ECLIPTIC_OF_DATE, "EclipticOfDate");
SIDERUST_DEFINE_FRAME(EclipticTrueOfDate, SIDERUST_FRAME_T_ECLIPTIC_TRUE_OF_DATE, "EclipticTrueOfDate");
SIDERUST_DEFINE_FRAME(EquatorialMeanJ2000, SIDERUST_FRAME_T_EQUATORIAL_MEAN_J2000, "EquatorialMeanJ2000");
SIDERUST_DEFINE_FRAME(EquatorialMeanOfDate, SIDERUST_FRAME_T_EQUATORIAL_MEAN_OF_DATE, "EquatorialMeanOfDate");
SIDERUST_DEFINE_FRAME(EquatorialTrueOfDate, SIDERUST_FRAME_T_EQUATORIAL_TRUE_OF_DATE, "EquatorialTrueOfDate");
SIDERUST_DEFINE_FRAME(Horizontal, SIDERUST_FRAME_T_HORIZONTAL, "Horizontal");
SIDERUST_DEFINE_FRAME(Galactic, SIDERUST_FRAME_T_GALACTIC, "Galactic");
SIDERUST_DEFINE_FRAME(ECEF, SIDERUST_FRAME_T_ECEF, "ECEF");
SIDERUST_DEFINE_FRAME(ITRF, SIDERUST_FRAME_T_ITRF, "ITRF");
SIDERUST_DEFINE_FRAME(CIRS, SIDERUST_FRAME_T_CIRS, "CIRS");
SIDERUST_DEFINE_FRAME(GCRS, SIDERUST_FRAME_T_GCRS, "GCRS");
SIDERUST_DEFINE_FRAME(TIRS, SIDERUST_FRAME_T_TIRS, "TIRS");
 
#undef SIDERUST_DEFINE_FRAME
 
// ============================================================================
// Naming Conventions (Spherical)
// ============================================================================
 
template <typename F>
struct SphericalNaming {
    static constexpr const char* lon_name() { return "longitude"; }
    static constexpr const char* lat_name() { return "latitude"; }
};
 
template <>
struct SphericalNaming<ICRS> {
    static constexpr const char* lon_name() { return "right_ascension"; }
    static constexpr const char* lat_name() { return "declination"; }
};
 
template <>
struct SphericalNaming<ICRF> {
    static constexpr const char* lon_name() { return "right_ascension"; }
    static constexpr const char* lat_name() { return "declination"; }
};
 
template <>
struct SphericalNaming<EquatorialMeanJ2000> {
    static constexpr const char* lon_name() { return "right_ascension"; }
    static constexpr const char* lat_name() { return "declination"; }
};
 
template <>
struct SphericalNaming<EquatorialMeanOfDate> {
    static constexpr const char* lon_name() { return "right_ascension"; }
    static constexpr const char* lat_name() { return "declination"; }
};
 
template <>
struct SphericalNaming<EquatorialTrueOfDate> {
    static constexpr const char* lon_name() { return "right_ascension"; }
    static constexpr const char* lat_name() { return "declination"; }
};
 
template <>
struct SphericalNaming<Horizontal> {
    static constexpr const char* lon_name() { return "azimuth"; }
    static constexpr const char* lat_name() { return "altitude"; }
};
 
template <>
struct SphericalNaming<Galactic> {
    static constexpr const char* lon_name() { return "l"; }
    static constexpr const char* lat_name() { return "b"; }
};
 
template <>
struct SphericalNaming<EclipticMeanJ2000> {
    static constexpr const char* lon_name() { return "ecliptic_longitude"; }
    static constexpr const char* lat_name() { return "ecliptic_latitude"; }
};
 
// ============================================================================
// Frame Capability Traits
// ============================================================================
 
template <typename F>
struct has_ra_dec : std::false_type {};
template <>
struct has_ra_dec<ICRS> : std::true_type {};
template <>
struct has_ra_dec<ICRF> : std::true_type {};
template <>
struct has_ra_dec<EquatorialMeanJ2000> : std::true_type {};
template <>
struct has_ra_dec<EquatorialMeanOfDate> : std::true_type {};
template <>
struct has_ra_dec<EquatorialTrueOfDate> : std::true_type {};
template <typename F>
inline constexpr bool has_ra_dec_v = has_ra_dec<F>::value;
 
template <typename F>
struct has_az_alt : std::false_type {};
template <>
struct has_az_alt<Horizontal> : std::true_type {};
template <typename F>
inline constexpr bool has_az_alt_v = has_az_alt<F>::value;
 
template <typename F>
struct has_lon_lat : std::false_type {};
template <>
struct has_lon_lat<EclipticMeanJ2000> : std::true_type {};
template <>
struct has_lon_lat<EclipticOfDate> : std::true_type {};
template <>
struct has_lon_lat<EclipticTrueOfDate> : std::true_type {};
template <>
struct has_lon_lat<Galactic> : std::true_type {};
template <>
struct has_lon_lat<CIRS> : std::true_type {};
template <>
struct has_lon_lat<GCRS> : std::true_type {};
template <>
struct has_lon_lat<TIRS> : std::true_type {};
template <>
struct has_lon_lat<ECEF> : std::true_type {};
template <>
struct has_lon_lat<ITRF> : std::true_type {};
template <typename F>
inline constexpr bool has_lon_lat_v = has_lon_lat<F>::value;
 
// ============================================================================
// Transform-Valid Predicate
// ============================================================================
 
template <typename From, typename To>
struct has_frame_transform : std::false_type {};
 
// Identity
template <typename F>
struct has_frame_transform<F, F> : std::true_type {};
 
// Hub spokes (bidirectional)
#define SIDERUST_FRAME_TRANSFORM_PAIR(A, B)               \
    template <>                                           \
    struct has_frame_transform<A, B> : std::true_type {}; \
    template <>                                           \
    struct has_frame_transform<B, A> : std::true_type {}
 
// All pairs reachable through the ICRS hub
SIDERUST_FRAME_TRANSFORM_PAIR(ICRS, EclipticMeanJ2000);
SIDERUST_FRAME_TRANSFORM_PAIR(ICRS, EquatorialMeanJ2000);
SIDERUST_FRAME_TRANSFORM_PAIR(ICRS, EquatorialMeanOfDate);
SIDERUST_FRAME_TRANSFORM_PAIR(ICRS, EquatorialTrueOfDate);
SIDERUST_FRAME_TRANSFORM_PAIR(EclipticMeanJ2000, EquatorialMeanJ2000);
SIDERUST_FRAME_TRANSFORM_PAIR(EclipticMeanJ2000, EquatorialMeanOfDate);
SIDERUST_FRAME_TRANSFORM_PAIR(EclipticMeanJ2000, EquatorialTrueOfDate);
SIDERUST_FRAME_TRANSFORM_PAIR(EquatorialMeanJ2000, EquatorialMeanOfDate);
SIDERUST_FRAME_TRANSFORM_PAIR(EquatorialMeanJ2000, EquatorialTrueOfDate);
SIDERUST_FRAME_TRANSFORM_PAIR(EquatorialMeanOfDate, EquatorialTrueOfDate);
// ICRF ≡ ICRS
SIDERUST_FRAME_TRANSFORM_PAIR(ICRF, EclipticMeanJ2000);
SIDERUST_FRAME_TRANSFORM_PAIR(ICRF, EquatorialMeanJ2000);
SIDERUST_FRAME_TRANSFORM_PAIR(ICRF, EquatorialMeanOfDate);
SIDERUST_FRAME_TRANSFORM_PAIR(ICRF, EquatorialTrueOfDate);
SIDERUST_FRAME_TRANSFORM_PAIR(ICRF, ICRS);
 
#undef SIDERUST_FRAME_TRANSFORM_PAIR
 
template <typename From, typename To>
inline constexpr bool has_frame_transform_v = has_frame_transform<From, To>::value;
 
template <typename F>
struct has_horizontal_transform : std::false_type {};
 
template <>
struct has_horizontal_transform<ICRS> : std::true_type {};
template <>
struct has_horizontal_transform<ICRF> : std::true_type {};
template <>
struct has_horizontal_transform<EclipticMeanJ2000> : std::true_type {};
template <>
struct has_horizontal_transform<EquatorialMeanJ2000> : std::true_type {};
template <>
struct has_horizontal_transform<EquatorialMeanOfDate> : std::true_type {};
template <>
struct has_horizontal_transform<EquatorialTrueOfDate> : std::true_type {};
 
template <typename F>
inline constexpr bool has_horizontal_transform_v = has_horizontal_transform<F>::value;
 
} // namespace frames
} // namespace siderust