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

#include <catch2/catch_all.hpp>

#include "../image_analysis/geom_refinement/PostRefine.h"

namespace {
    PostRefineResult Measured(double residual, double se) {
        PostRefineResult r;
        r.held_out_before = residual;
        r.held_out_before_se = se;
        return r;
    }

    PostRefineResult Fit(UnitCell before, UnitCell after) {
        PostRefineResult r;
        r.cell_refined = true;
        r.cell_before = before;
        r.cell = after;
        return r;
    }

    UnitCell Cell(float a, float b, float c) {
        return UnitCell{.a = a, .b = b, .c = c, .alpha = 90.0f, .beta = 90.0f, .gamma = 90.0f};
    }
}

TEST_CASE("PostRefine_HeldOutResidualFell", "[PostRefine]") {
    // Down by more than the standard error of the difference, sqrt(3^2 + 4^2) = 5.
    CHECK(HeldOutResidualFell(Measured(100.0, 3.0), Measured(94.0, 4.0)));
    // Down, but within that noise.
    CHECK_FALSE(HeldOutResidualFell(Measured(100.0, 3.0), Measured(96.0, 4.0)));
    // Up.
    CHECK_FALSE(HeldOutResidualFell(Measured(100.0, 3.0), Measured(110.0, 4.0)));
    // Not measured on either side.
    CHECK_FALSE(HeldOutResidualFell(PostRefineResult{}, Measured(10.0, 1.0)));
    CHECK_FALSE(HeldOutResidualFell(Measured(100.0, 3.0), PostRefineResult{}));
}

TEST_CASE("PostRefine_ReindexPushesCellBack", "[PostRefine]") {
    // The fit shortens b the most; re-indexing at its geometry returns a longer b: pushed back.
    const auto fit = Fit(Cell(96.9f, 107.9f, 112.9f), Cell(96.8f, 106.6f, 112.9f));
    CHECK(ReindexPushesCellBack(fit, Fit(Cell(96.7f, 107.6f, 112.6f), Cell(96.6f, 106.4f, 112.8f))) == -2);
    // A walk that re-indexing follows (and overshoots a little) is not pushed back.
    const auto walk = Fit(Cell(60.48f, 60.48f, 196.7f), Cell(60.05f, 60.05f, 195.2f));
    CHECK(ReindexPushesCellBack(walk, Fit(Cell(60.00f, 60.00f, 195.1f), Cell(59.8f, 59.8f, 194.2f))) == 0);
    // Nothing committed, or no cell measured by the next pass: no evidence either way.
    PostRefineResult refused = fit;
    refused.cell_refined = false;
    CHECK(ReindexPushesCellBack(refused, Fit(Cell(96.7f, 107.6f, 112.6f), Cell(96.6f, 106.4f, 112.8f))) == 0);
    CHECK(ReindexPushesCellBack(fit, PostRefineResult{}) == 0);
}