// SPDX-FileCopyrightText: 2024 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
// SPDX-License-Identifier: GPL-3.0-only

#include "UnitCell.h"

#include <algorithm>
#include <cmath>

bool UnitCell::is_finite() const {
    return std::isfinite(a)
           && std::isfinite(b)
           && std::isfinite(c)
           && std::isfinite(alpha)
           && std::isfinite(beta)
           && std::isfinite(gamma);
}

bool UnitCell::is_close(const UnitCell &ref, float dist_tolerance, float angle_tolerance_deg) const {
    if (!is_finite() || !ref.is_finite())
        return false;

    constexpr float min_length = 1e-6f;

    if (std::fabs(a - ref.a) / std::max(std::fabs(ref.a), min_length) > dist_tolerance)
        return false;
    if (std::fabs(b - ref.b) / std::max(std::fabs(ref.b), min_length) > dist_tolerance)
        return false;
    if (std::fabs(c - ref.c) / std::max(std::fabs(ref.c), min_length) > dist_tolerance)
        return false;

    if (std::fabs(alpha - ref.alpha) > angle_tolerance_deg)
        return false;
    if (std::fabs(beta - ref.beta) > angle_tolerance_deg)
        return false;
    if (std::fabs(gamma - ref.gamma) > angle_tolerance_deg)
        return false;

    return true;
}

std::ostream &operator<<(std::ostream &output, const UnitCell &in) {
    output << in.a << " " << in.b << " " << in.c;
    output << " " << in.alpha << " " << in.beta << " " << in.gamma;
    return output;
}

std::optional<UnitCell> MeanUnitCell(const std::vector<UnitCell> &cells) {
    if (cells.empty())
        return {};

    UnitCell ret{};
    for (const auto &cell: cells) {
        ret.a += cell.a;
        ret.b += cell.b;
        ret.c += cell.c;
        ret.alpha += cell.alpha;
        ret.beta += cell.beta;
        ret.gamma += cell.gamma;
    }

    const auto scale = 1.0f / static_cast<float>(cells.size());
    ret.a *= scale;
    ret.b *= scale;
    ret.c *= scale;
    ret.alpha *= scale;
    ret.beta *= scale;
    ret.gamma *= scale;

    return ret;
}

UnitCell::operator gemmi::UnitCell() const {
    return {a, b, c, alpha, beta, gamma};
}