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

#pragma once

#include <cmath>
#include <cstdint>
#include <stdexcept>

#include <tuple>
#include "../../common/Reflection.h"
#include "gemmi/symmetry.hpp"

struct HKLKey {
    int h = 0;
    int k = 0;
    int l = 0;
    bool plus = true;

    bool operator<(const HKLKey &o) const {
        return std::tie(h, k, l, plus) < std::tie(o.h, o.k, o.l, o.plus);
    }
    bool operator==(const HKLKey &o) const {
        return h == o.h && k == o.k && l == o.l && plus == o.plus;
    }

    [[nodiscard]] uint64_t pack() const;
    // The key pack() made, back.
    [[nodiscard]] static HKLKey unpack(uint64_t packed);
};

class HKLKeyGenerator {
    bool merge_friedel;
    gemmi::SpaceGroup sg;
    gemmi::GroupOps ops;
    gemmi::ReciprocalAsu asu;

public:
    HKLKeyGenerator(bool merge_friedel, const gemmi::SpaceGroup &sg);
    HKLKey operator()(const Reflection &r) const;
    HKLKey operator()(const MergedReflection &r) const;
    HKLKey operator()(int32_t h, int32_t k, int32_t l) const;

    bool IsSystematicallyAbsent(int32_t h, int32_t k, int32_t l) const;
    bool IsSystematicallyAbsent(const Reflection &r) const;
};

HKLKey CanonicalHKL(const Reflection &r, bool merge_friedel, const std::optional<gemmi::SpaceGroup> &sg);
HKLKey CanonicalHKL(const MergedReflection &r, bool merge_friedel, const std::optional<gemmi::SpaceGroup> &sg);
HKLKey CanonicalHKL(int32_t h, int32_t k, int32_t l, bool merge_friedel, const std::optional<gemmi::SpaceGroup> &sg);

bool AcceptReflection(const Reflection &r, std::optional<double> d_min_limit, std::optional<double> d_max_limit);
bool AcceptReflection(const Reflection &r, double d_min_limit, double d_max_limit);