#pragma once

#include <base/subface.hpp>

namespace internal
{
// local: cylinder face x^2+y^2-1=0
struct cylinder_face_t final : subface {
    static constexpr uint64_t             max_degree  = 2;
    static constexpr equation_system_type eq_sys_type = equation_system_type::implicit;

    std::function<double(Eigen::Vector3d)>          fetch_sdf_evaluator() const override;
    std::function<Eigen::Vector3d(Eigen::Vector3d)> fetch_sdf_grad_evaluator() const override;

    // u: planar angle from x-axis to z-axis
    // v: depth/height from xz-plane to y-axis
    std::function<Eigen::Vector4d(double, double)> fetch_point_by_param_evaluator() const override;

    std::function<constraint_curve_intermediate(double)> fetch_curve_constraint_evaluator(parameter_u_t constraint_var_type,
                                                                                          double        u) const override;
    std::function<constraint_curve_intermediate(double)> fetch_curve_constraint_evaluator(parameter_v_t constraint_var_type,
                                                                                          double        v) const override;
    std::function<equation_intermediate_t(constraint_curve_intermediate &&)> fetch_solver_evaluator() const override;
};

struct cylinder_paired_model_matrix {
    internal::paired_model_matrix *data{};
};
} // namespace internal

namespace detail
{
template <>
struct hasher<internal::cylinder_paired_model_matrix> {
    size_t operator()(const internal::cylinder_paired_model_matrix &block) const
    {
        const auto& mat = block.data->local_to_world.matrix(); // 3x4
        Eigen::Matrix3d A = mat.block<3,3>(0,0);               
        Eigen::Vector3d b = mat.col(3);

        Eigen::Matrix3d B = A.inverse();
        Eigen::Matrix<double, 2, 3> R = B.topRows<2>();

        Eigen::Matrix3d G = R.transpose() * R;
        Eigen::Vector2d zero_proj = R * b;

        size_t h = XXH3_64bits(G.data(), sizeof(Eigen::Matrix3d));
        h ^= XXH3_64bits(zero_proj.data(), sizeof(Eigen::Vector2d));

        return h;
    }
};

template <>
struct default_elem_ctor<internal::cylinder_paired_model_matrix, internal::cylinder_face_t> {
    internal::cylinder_face_t operator()(const internal::cylinder_paired_model_matrix &k) const
    {
        internal::cylinder_face_t res{};
        res.model_matrices = const_cast<internal::paired_model_matrix *>(k.data);
        return res;
    }
};
} // namespace detail