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

#include "BraggPrediction.h"

BraggPrediction::BraggPrediction(const DiffractionExperiment &experiment,
                                 const CrystalLattice &lattice,
                                 float high_res_A,
                                 float angle_dist_cutoff) {

    auto geom = experiment.GetDiffractionGeometry();
    auto det_width_pxl = static_cast<float>(experiment.GetXPixelsNum());
    auto det_height_pxl = static_cast<float>(experiment.GetYPixelsNum());

    Coord Astar = lattice.Astar();
    Coord Bstar = lattice.Bstar();
    Coord Cstar = lattice.Cstar();

    for (int h = -max_hkl; h < max_hkl; h++) {
        for (int k = -max_hkl; k < max_hkl; k++) {
            for (int l = -max_hkl; l < max_hkl; l++) {
                Coord recip = Astar * static_cast<float>(h)
                              + Bstar * static_cast<float>(k)
                              + Cstar * static_cast<float>(l);
                float d = 1.0f / recip.Length();
                if (d < high_res_A)
                    continue;

                float dist_ewald_sphere = geom.DistFromEwaldSphere(recip);
                float angle_ewald_sphere = geom.AngleFromEwaldSphere(recip);
                if (!std::isfinite(angle_ewald_sphere) || angle_ewald_sphere > angle_dist_cutoff )
                    continue;

                auto [x,y] = geom.RecipToDector(recip);

                if ((x < 0) || (x >= det_width_pxl) || (y < 0) || (y >= det_height_pxl))
                    continue;

                reflections.insert(std::make_pair(angle_ewald_sphere, Reflection{
                                .h = h,
                                .k = k,
                                .l = l,
                                .center_x_pxl = x,
                                .center_y_pxl = y,
                                .radius_ewald_sphere = dist_ewald_sphere,
                                .angle_ewald_sphere = angle_ewald_sphere,
                                .d = d
                        }));
            }
        }
    }
}

const std::multimap<float, Reflection> &BraggPrediction::GetReflections() const {
    return reflections;
}

std::vector<Reflection> BraggPrediction::GetReflections(float max_radius) const {
    std::vector<Reflection> result;

    auto it = reflections.upper_bound(max_radius);
    for (auto iter = reflections.begin(); iter != it; ++iter)
        result.push_back(iter->second);

    return result;
}