// SPDX-FileCopyrightText: 2026 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
// SPDX-License-Identifier: GPL-3.0-only

#pragma once

#include <vector>
#include <Eigen/Dense>

#include "../../common/Coord.h"
#include "Indexer.h"

// The best cells of the fast-feedback indexer for one input cell, before Refine(): three rows per
// cell (the real-space cell vectors), scores ascending - lower is better. The layout of the GPU
// library's oCellM()/oScoreV(), so both feed Refine() the same way.
struct FFBIDXCells {
    Eigen::MatrixX3<float> cells;
    Eigen::VectorX<float> scores;
};

// The fast-feedback indexer on the CPU: same samples, scores and output as the GPU library.
// cell holds the real-space cell vectors as rows; the first nspots of spots are used.
FFBIDXCells FFBIDXFindCells(const Eigen::Matrix3f &cell, const std::vector<Coord> &spots, size_t nspots);

class FFBIDXIndexerCPU : public Indexer {
    Eigen::Matrix3f input_cell;

    void SetupUnitCell(const std::optional<UnitCell> &cell) override;
public:
    std::vector<CrystalLattice> RunInternal(const std::vector<Coord> &coord, size_t nspots) override;
};