#pragma once

#include <base/subface.hpp>

namespace internal
{
// local: a sphere with center at (0, 0, 0) and radius 1
// u: planar angle from x-axis to z-axis
// v: polar angle from xz-plane to y-axis
// EDIT: recap v from [-pi/2, pi/2] to [0, pi]
struct sphere_face_t final : subface {
};
} // namespace internal

namespace detail
{
// Q' = M^{-T}QM^{-1}
// Q = {
// 1, 0, 0, 0
// 0, 1, 0, 0
// 0, 0, 1, 0
// 0, 0, 0, -1
// }
const Eigen::Vector4d sphere_std_diag{1, 1, 1, -1};

template <>
inline size_t hasher<internal::sphere_face_t>::operator()(const internal::sphere_face_t& subface) const
{
    return hash_funcs(get_quadrics_character(sphere_std_diag, subface));
}

template <>
inline bool eq_compare<internal::sphere_face_t>::operator()(const internal::sphere_face_t& lhs,
                                                            const internal::sphere_face_t& rhs) const
{
    return eq_funcs(get_quadrics_character(sphere_std_diag, lhs), get_quadrics_character(sphere_std_diag, rhs));
}
} // namespace detail