// SPDX-FileCopyrightText: 2025 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
// SPDX-License-Identifier: GPL-3.0-only

#pragma once

#include <optional>
#include <cstdint>
#include <vector>

class ResolutionShells {
    const float d_min, d_max;
    const float one_over_dmin2, one_over_dmax2;
    const int32_t nshells;
public:
    // Shells of equal width in 1/d^2 between d_min (exclusive) and d_max (inclusive). d_max may be
    // infinite, which is "no low-resolution bound": the shells then start at 1/d^2 = 0.
    ResolutionShells(float d_min, float d_max, int32_t nshells);
    [[nodiscard]] std::optional<int32_t> GetShell(float d) const;
    [[nodiscard]] std::vector<float> GetShellMeanOneOverResSq() const;
    [[nodiscard]] std::vector<float> GetShellMinRes() const;
};