// 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 <cmath>

#include "../common/JFJochException.h"
#include "../reader/SweepLayout.h"

namespace {

// A series of frames all taken at the same instrument setting, at the angles given.
std::vector<sweep::Frame> Series(const std::vector<double> &angles, double increment) {
    std::vector<sweep::Frame> out;
    out.reserve(angles.size());
    for (size_t i = 0; i < angles.size(); i++)
        out.push_back({"f" + std::to_string(i) + ".cbf", angles[i], increment, 0.2, 1000, 1000, 1.0});
    return out;
}

}  // namespace

TEST_CASE("SweepLayout_Contiguous") {
    std::vector<double> angles;
    for (int i = 0; i < 100; i++)
        angles.push_back(20.0 + 0.1 * i);
    const auto l = sweep::Place(Series(angles, 0.1), "test");
    CHECK(l.files.size() == 100);
    CHECK(l.present == 100);
    CHECK(l.start_deg == Catch::Approx(20.0));
    CHECK(l.increment_deg == Catch::Approx(0.1));
    for (size_t i = 0; i < l.files.size(); i++)
        CHECK(l.files[i] == "f" + std::to_string(i) + ".cbf");
}

TEST_CASE("SweepLayout_Gapped") {
    // Frames 3, 4 and 7 of a ten-frame sweep never made it into the archive. The sweep is still ten
    // steps wide and every frame keeps its own angle.
    const auto l = sweep::Place(Series({0.0, 0.1, 0.2, 0.5, 0.6, 0.8, 0.9}, 0.1), "test");
    REQUIRE(l.files.size() == 10);
    CHECK(l.present == 7);
    CHECK(l.increment_deg == Catch::Approx(0.1));
    CHECK(l.files[2] == "f2.cbf");
    CHECK(l.files[3].empty());
    CHECK(l.files[4].empty());
    CHECK(l.files[5] == "f3.cbf");
    CHECK(l.files[7].empty());
    CHECK(l.files[9] == "f6.cbf");
}

TEST_CASE("SweepLayout_PastFullTurn") {
    // A writer that starts over at 0 rather than counting on past 360.
    const auto l = sweep::Place(Series({359.7, 359.8, 359.9, 0.0, 0.1}, 0.1), "test");
    CHECK(l.files.size() == 5);
    CHECK(l.present == 5);
    CHECK(l.increment_deg == Catch::Approx(0.1));
}

TEST_CASE("SweepLayout_MultiTurn") {
    // One continuous 540 degree sweep, 2700 frames of 0.2 deg, whose headers write the start angle
    // modulo 360: from frame 1476 on, every angle repeats one the first revolution already had. The
    // second and third revolutions must occupy fresh slots, not land on top of the first.
    std::vector<double> angles;
    for (int i = 0; i < 2700; i++)
        angles.push_back(std::fmod(65.0 + 0.2 * i, 360.0));
    const auto l = sweep::Place(Series(angles, 0.2), "test");
    REQUIRE(l.files.size() == 2700);
    CHECK(l.present == 2700);
    CHECK(l.start_deg == Catch::Approx(65.0));
    CHECK(l.increment_deg == Catch::Approx(0.2));
    // The sweep really is 540 degrees wide, and no frame was dropped on top of another.
    CHECK(l.increment_deg * static_cast<double>(l.files.size() - 1) == Catch::Approx(539.8));
    CHECK(l.files.back() == "f2699.cbf");
}

TEST_CASE("SweepLayout_MultiTurnWithReadbackNoise") {
    // The same sweep as a real header writes it: the recorded angles come from 32-bit floats, so
    // each is a few parts in 100000 off the grid. Estimating the step from ONE recorded difference
    // scales that noise by the frame number - the series it was measured on drifted a quarter of a
    // step by frame 1924 and was refused as scattered.
    std::vector<double> angles;
    for (int i = 0; i < 2700; i++)
        angles.push_back(std::fmod(static_cast<double>(static_cast<float>(65.0 + 0.2 * i)), 360.0));
    const auto l = sweep::Place(Series(angles, 0.2), "test");
    REQUIRE(l.files.size() == 2700);
    CHECK(l.present == 2700);
    CHECK(l.increment_deg == Catch::Approx(0.2).epsilon(1e-6));
    CHECK(l.start_deg == Catch::Approx(65.0).epsilon(1e-6));
}

TEST_CASE("SweepLayout_MultiTurnGapped") {
    // Past 360 AND missing frames: the two have to work together, because a gap is what the step
    // guess has to survive and a full turn is what the step count has to carry through.
    std::vector<double> angles;
    for (int i = 0; i < 2000; i++)
        if (i % 7 != 3)
            angles.push_back(std::fmod(10.0 + 0.25 * i, 360.0));
    const auto l = sweep::Place(Series(angles, 0.25), "test");
    CHECK(l.files.size() == 2000);
    CHECK(l.present == angles.size());
    CHECK(l.increment_deg == Catch::Approx(0.25));
    CHECK(l.files[3].empty());
    CHECK(l.files[1999] == "f" + std::to_string(angles.size() - 1) + ".cbf");
}

TEST_CASE("SweepLayout_ConcatenatedSweepsStillRefused") {
    // Two 90 degree sweeps of one crystal in one directory. Unlike a sweep that runs past 360, this
    // one goes BACK: the second series returns to angles the first already covered without having
    // stepped forward through a whole turn to get there.
    std::vector<double> angles;
    for (int i = 0; i < 90; i++) angles.push_back(0.5 * i);
    for (int i = 0; i < 90; i++) angles.push_back(0.5 * i);
    CHECK_THROWS_AS(sweep::Place(Series(angles, 0.5), "test"), JFJochException);
}

TEST_CASE("SweepLayout_Reversed") {
    const auto l = sweep::Place(Series({10.0, 9.5, 9.0, 8.0}, 0.5), "test");
    REQUIRE(l.files.size() == 5);
    CHECK(l.increment_deg == Catch::Approx(-0.5));
    CHECK(l.files[3].empty());
    CHECK(l.files[4] == "f3.cbf");
}

TEST_CASE("SweepLayout_Stills") {
    // Nothing turns: the files are the images, and the header's nominal increment stands.
    const auto l = sweep::Place(Series({45.0, 45.0, 45.0}, 0.1), "test");
    CHECK(l.files.size() == 3);
    CHECK(l.present == 3);
    CHECK(l.start_deg == Catch::Approx(45.0));
    CHECK(l.increment_deg == Catch::Approx(0.1));
}

TEST_CASE("SweepLayout_ScreeningImagesRefused") {
    // Five shots at scattered angles are not a sweep, and must not be laid out as one.
    CHECK_THROWS_AS(sweep::Place(Series({0.0, 90.0, 45.0, 300.0, 270.0}, 0.5), "test"),
                    JFJochException);
}

TEST_CASE("SweepLayout_MovedDetectorRefused") {
    auto frames = Series({0.0, 0.1, 0.2, 0.3}, 0.1);
    frames[2].distance_m = 0.3;
    CHECK_THROWS_AS(sweep::Place(frames, "test"), JFJochException);
}

TEST_CASE("SweepLayout_SecondWavelengthRefused") {
    auto frames = Series({0.0, 0.1, 0.2, 0.3}, 0.1);
    frames[3].wavelength_A = 1.9;
    CHECK_THROWS_AS(sweep::Place(frames, "test"), JFJochException);
}

TEST_CASE("SweepLayout_RepeatedAngleRefused") {
    // Two sweeps of the same crystal concatenated: the second covers angles the first already has.
    CHECK_THROWS_AS(sweep::Place(Series({0.0, 0.1, 0.2, 0.1, 0.2}, 0.1), "test"), JFJochException);
}