#include "capture_file_writer.h"
#include "channel_bundle_support.hpp"
#include "data_preprocessor.hpp"
#include "locator/tcp_server.hpp"
#include "object_approach_filter.hpp"
#include "processing_live_config.hpp"
#include "runtime_wait.hpp"
#include "shm_ring.hpp"
#include "tty_protocol_writer.h"

#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <unistd.h>

#include <algorithm>
#include <array>
#include <atomic>
#include <chrono>
#include <cstring>
#include <exception>
#include <filesystem>
#include <fstream>
#include <iostream>
#include <limits>
#include <random>
#include <stdexcept>
#include <thread>

#include <nlohmann/json.hpp>

namespace {
using namespace radar;
using Json = nlohmann::json;

void require(bool condition, const char* message) {
    if (!condition) {
        throw std::runtime_error(message);
    }
}

template <typename Callable>
void expect_error(Callable operation) {
    try {
        operation();
    } catch (const std::bad_alloc&) {
        throw;  // A malformed count must be rejected before allocating.
    } catch (const std::exception&) {
        return;
    }
    throw std::runtime_error("Expected operation to reject malformed input");
}

struct Workspace {
    std::filesystem::path path;
    Workspace() {
        char pattern[] = "/tmp/radar-native-XXXXXX";
        const auto* created = ::mkdtemp(pattern);
        require(created != nullptr, "mkdtemp failed");
        path = created;
    }
    ~Workspace() { std::filesystem::remove_all(path); }
};

struct RingName {
    std::string name;
    explicit RingName(const std::string& suffix = {})
        : name("/radar_native_test_" + std::to_string(::getpid()) + suffix) {
        ::shm_unlink(name.c_str());
    }
    ~RingName() { ::shm_unlink(name.c_str()); }
};

auto save_bundle(const Workspace& workspace, const char* name, const ipc::RawSweepCollection& collection)
    -> std::string {
    const auto path = workspace.path / name;
    const auto bytes = ipc::serialize_raw_collection(collection);
    std::ofstream(path, std::ios::binary).write(
        reinterpret_cast<const char*>(bytes.data()), static_cast<std::streamsize>(bytes.size()));
    return path.string();
}

void write_u32(std::vector<std::uint8_t>& bytes, std::size_t offset, std::uint32_t value) {
    require(offset + sizeof(value) <= bytes.size(), "invalid test offset");
    std::memcpy(bytes.data() + offset, &value, sizeof(value));
}

void test_wire_format() {
    ipc::RawSweepCollection raw{.collection_id = 7, .monotonic_ns = 42,
        .capture_start_ns = 21, .capture_end_ns = 40,
        .traces = {{.combo = {1, 2}, .frequency_hz = {1, 2},
            .s21 = {{5, 6}, {7, 8}},
            .capture_start_ns = 25, .capture_end_ns = 39}}};
    ipc::ResultCollection results{.collection_id = 7, .monotonic_ns = 0x0102030405060708ULL,
        .processing_duration_ns = 17, .settings_revision = 0xfedcba9876543210ULL,
        .capture_start_ns = 21, .capture_end_ns = 40, .speed_m_s = -1.5F,
        .collection_payloads = {
            {.kind = ipc::ResultKind::TraceComplex, .frequency_hz = {1}, .trace = {{2, 3}}},
            {.kind = ipc::ResultKind::ScalarF32, .scalar_value = 4},
            {.kind = ipc::ResultKind::ImageF32, .image_x_axis = {1, 2},
                .image_y_axis = {3}, .image_values = {4, 5}},
            {.kind = ipc::ResultKind::TableF32, .table_columns = 2, .table_values = {6, 7}},
            {.kind = ipc::ResultKind::ImageF32, .image_y_axis = {1}},
            {.kind = ipc::ResultKind::TableF32, .table_columns = 3}},
        .blocks = {{.combo = {1, 2}, .payloads = {{.kind = ipc::ResultKind::ScalarF32}}}}};
    const auto raw_bytes = ipc::serialize_raw_collection(raw);
    const auto pre_bytes = ipc::serialize_preprocessed_collection(raw);
    const auto result_bytes = ipc::serialize_result_collection(results);
    const std::array<std::uint8_t, 64> result_header{
        'R', 'S', 'L', '3', 7, 0, 0, 0, 0, 0, 0, 0,
        8, 7, 6, 5, 4, 3, 2, 1, 17, 0, 0, 0, 0, 0, 0, 0,
        0x10, 0x32, 0x54, 0x76, 0x98, 0xba, 0xdc, 0xfe,
        21, 0, 0, 0, 0, 0, 0, 0, 40, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0xc0, 0xbf, 6, 0, 0, 0, 1, 0, 0, 0,
    };
    require(std::equal(result_header.begin(), result_header.end(), result_bytes.begin()),
        "RSL3 must preserve exact acquisition identity and settings in its 64-byte header");
    require(std::memcmp(raw_bytes.data(), "RAW3", 4) == 0 &&
            std::memcmp(pre_bytes.data(), "PRP3", 4) == 0,
        "trace collections must use the S21-only version 3 format");
    // Collection header + one trace header + two 12-byte points + capture trailer.
    require(raw_bytes.size() == 24 + 12 + 2 * 12 + 16 + 4 + 16 && pre_bytes.size() == raw_bytes.size(),
        "trace wire format must contain only frequency and S21 samples");
    auto old_raw = raw_bytes;
    auto old_pre = pre_bytes;
    write_u32(old_raw, 0, 0x32574152U);
    write_u32(old_pre, 0, 0x32525050U);
    expect_error([&] { (void)ipc::deserialize_raw_collection(old_raw); });
    expect_error([&] { (void)ipc::deserialize_preprocessed_collection(old_pre); });
    require(ipc::serialize_raw_collection(ipc::deserialize_raw_collection(raw_bytes)) == raw_bytes,
        "raw roundtrip changed data");
    require(ipc::serialize_preprocessed_collection(ipc::deserialize_preprocessed_collection(pre_bytes)) == pre_bytes,
        "preprocessed roundtrip changed data");
    for (const std::size_t tail : {36U, 20U}) {
        expect_error([&] { (void)ipc::deserialize_raw_collection(std::span(raw_bytes).first(raw_bytes.size() - tail)); });
        expect_error([&] { (void)ipc::deserialize_preprocessed_collection(std::span(pre_bytes).first(pre_bytes.size() - tail)); });
    }
    // Deterministic random mutations include wire-compatible valid frames as seeds.
    std::mt19937 random(0x52414452U);
    for (unsigned iteration = 0; iteration < 10'000U; ++iteration) {
        auto bytes = iteration % 2U == 0U ? raw_bytes : pre_bytes;
        for (unsigned edit = 0; edit < 1U + random() % 5U; ++edit) {
            bytes[random() % bytes.size()] = static_cast<std::uint8_t>(random());
        }
        if (iteration % 4U == 0U) {
            bytes.resize(random() % bytes.size());
        }
        try {
            if (iteration % 2U == 0U) { (void)ipc::deserialize_raw_collection(bytes); }
            else { (void)ipc::deserialize_preprocessed_collection(bytes); }
        } catch (const std::bad_alloc&) { throw; }
        catch (const std::runtime_error&) {}
    }
}

void test_configuration(const std::string& seed_path, const Workspace& workspace) {
    std::ifstream input(seed_path);
    const auto seed = Json::parse(input);
    const auto config_path = workspace.path / "config.json";
    const auto save = [&](const Json& config) { std::ofstream(config_path) << config; };
    save(seed);
    const auto config = config::load_run_config(config_path.string());
    auto no_taps = seed;
    no_taps["rings"]["preprocessed_tap"]["name"] = "";
    save(no_taps);
    const auto disabled = config::load_run_config(config_path.string()).rings;
    require(disabled.preprocessed_tap.name.empty(),
        "explicit empty tap names must disable the optional rings");
    for (const auto* key : {"raw", "preprocessed", "results"}) {
        auto invalid = no_taps;
        invalid["rings"][key]["name"] = "";
        save(invalid);
        expect_error([&] { (void)config::load_run_config(config_path.string()); });
    }
    for (const auto* port : {"port1", "port2"}) {
        auto with_driver = seed;
        with_driver["switches"][port]["driver"] = "h7992";
        save(with_driver);
        (void)config::load_run_config(config_path.string());
        for (const auto& driver : {Json("hmc349a"), Json("unknown"), Json(7)}) {
            with_driver["switches"][port]["driver"] = driver;
            save(with_driver);
            expect_error([&] { (void)config::load_run_config(config_path.string()); });
        }
    }
    auto with_object_calibration = seed;
    with_object_calibration["preprocess"]["s21"]["object_calibration"] =
        Json{{"set_name", "reflector"}, {"bundle_path", "corrections.bin"}};
    save(with_object_calibration);
    const auto selected = config::load_run_config(config_path.string()).preprocess.s21.object_calibration;
    require(selected.bundle_path == "corrections.bin",
        "object calibration asset did not load");
    with_object_calibration["preprocess"]["s21"].erase("object_calibration");
    save(with_object_calibration);
    require(config::load_run_config(config_path.string()).preprocess.s21.object_calibration.bundle_path.empty(),
        "absent object calibration was not disabled");
    for (const auto& invalid_asset : {Json(nullptr), Json{{"bundle_path", true}}}) {
        with_object_calibration["preprocess"]["s21"]["object_calibration"] = invalid_asset;
        save(with_object_calibration);
        expect_error([&] { (void)config::load_run_config(config_path.string()); });
    }
    for (const auto& [pointer, value] : std::array<std::pair<const char*, double>, 3>{{
        {"/run/combos/0/input", 0.0000001},
        {"/rings/raw/slot_size_bytes", 65}, {"/gpr/rx_geometry/0/x_m", 1e100}}}) {
        auto invalid = seed;
        invalid[Json::json_pointer(pointer)] = value;
        save(invalid);
        expect_error([&] { (void)config::load_run_config(config_path.string()); });
    }
    const auto live_path = workspace.path / "live.json";
    std::ofstream(live_path) << Json{{"bscan_gain", 2}, {"settings_revision", 11}};
    processing::ProcessingLiveConfigLoader loader(live_path.string(), config);
    require(loader.refresh_if_needed().bscan_gain == 2, "valid live config did not load");
    const auto revision = loader.revision();
    for (const auto& invalid : {Json{{"bscan_gain", 1e100}},
             Json{{"gpr_input_positions", {0.0000001}}}, Json{{"bscan_gain", true}}}) {
        std::ofstream(live_path) << invalid;
        std::this_thread::sleep_for(std::chrono::milliseconds(110));
        const auto current = loader.refresh_if_needed();
        require(current.bscan_gain == 2 && loader.revision() == revision,
            "invalid live config replaced the last valid settings");
    }
}

void test_ring() {
    RingName name;
    expect_error([&] { (void)ipc::ShmRing::open_or_create(name.name, 2, 65); });
    expect_error([&] { (void)ipc::ShmRing::open_or_create(name.name, 0xffffffffU, 0xfffffff8U); });
    auto ring = ipc::ShmRing::open_or_create(name.name, 2, 4096);
    const auto child = ::fork();
    require(child >= 0, "fork failed");
    if (child == 0) {
        std::array<std::uint64_t, 512> words{};
        for (std::uint64_t sequence = 1; sequence <= 20'000U; ++sequence) {
            words.fill(sequence);
            if (!ring.push({reinterpret_cast<const std::uint8_t*>(words.data()), sizeof(words)})) {
                ::_exit(2);
            }
        }
        ::_exit(0);
    }
    std::uint64_t previous = 0;
    std::vector<std::uint8_t> payload;
    int status = 0;
    bool finished = false;
    const auto deadline = std::chrono::steady_clock::now() + std::chrono::seconds(10);
    try {
        while (true) {
            if (ring.pop(payload)) {
                require(payload.size() == 4096, "stress payload changed size");
                std::uint64_t sequence = 0;
                std::memcpy(&sequence, payload.data(), sizeof(sequence));
                require(sequence > previous, "stress ring yielded duplicate or older data");
                for (std::size_t offset = 0; offset < payload.size(); offset += sizeof(sequence)) {
                    std::uint64_t word = 0;
                    std::memcpy(&word, payload.data() + offset, sizeof(word));
                    require(word == sequence, "stress ring accepted a torn payload");
                }
                previous = sequence;
            } else if (finished) { break; }
            finished = finished || ::waitpid(child, &status, WNOHANG) == child;
            require(std::chrono::steady_clock::now() < deadline, "ring stress timed out");
        }
        require(WIFEXITED(status) && WEXITSTATUS(status) == 0 && previous != 0,
            "ring stress writer failed");
    } catch (...) {
        ::kill(child, SIGKILL);
        if (!finished) { (void)::waitpid(child, &status, 0); }
        throw;
    }
}

void test_acquisition_identity() {
    processing::ObjectApproachFilter filter;
    const std::vector<processing::ObjectApproachFilter::Point> points{{0, 2}};
    require(!filter.confirm(points, 1, 1'000'000'000ULL, 0, 0, 2).front(), "first frame confirmed a track");
    require(filter.confirm(points, 1, 2'000'000'000ULL, 0, 0, 2).front(),
        "reused collection id replaced a distinct acquisition");
    require(filter.confirm(points, 1, 2'000'000'000ULL, 0, 0, 2).front(),
        "reprocessing duplicated a frame or lost its predecessor");
    require(!filter.confirm(points, 7, 1'000'000'000ULL, 0, 0, 2).front(),
        "an earlier capture time failed to reset replay history");
}

void test_interruptible_wait() {
    std::atomic<bool> stop{false};
    std::jthread request_stop([&] {
        std::this_thread::sleep_for(std::chrono::milliseconds(10));
        stop.store(true);
    });
    const auto start = std::chrono::steady_clock::now();
    require(config::wait_or_stop(0xffffffffU, stop), "large wait ignored stop");
    require(std::chrono::steady_clock::now() - start < std::chrono::seconds(1),
        "large wait delayed shutdown");
}

void test_cosine_notch_taper() {
    // Band 2.0-2.1 GHz with 0.1 GHz shoulders: 1 at the outer edges, 0.5 halfway,
    // 0 from the band edges inwards.
    const std::vector<float> frequency_hz{1.85e9F, 1.9e9F, 1.95e9F, 2.0e9F, 2.05e9F,
                                          2.1e9F, 2.15e9F, 2.2e9F, 2.25e9F};
    const std::vector<float> expected{1.0F, 1.0F, 0.5F, 0.0F, 0.0F, 0.0F, 0.5F, 1.0F, 1.0F};
    const auto mask = preprocessing::build_notch_mask(frequency_hz,
        {.enabled = true, .bands_hz = {{2.0e9F, 2.1e9F}}, .taper_width_hz = 1e8F, .taper_type = "cosine"});
    for (std::size_t index = 0U; index < expected.size(); ++index) {
        require(std::abs(mask[index] - expected[index]) < 1e-3F, "cosine notch shoulders are not 1 -> 0 towards the band");
    }
}

void test_csv_failures(const Workspace& workspace) {
    const auto csv = workspace.path / "capture.csv";
    const auto spool = workspace.path / "capture.capture_spool.bin";
    CaptureFileWriter writer(csv.string(), (workspace.path / "capture.svg").string(), "", "");
    writer.initialize_csv(2, false);
    CapturePacket packet{.ch1 = {1, 2}, .ch2 = {3, 4}, .di1 = {}};
    auto invalid_packet = packet;
    invalid_packet.ch2.pop_back();
    expect_error([&] { writer.append_csv_packet(invalid_packet); });
    require(std::filesystem::file_size(spool) == 16, "invalid packet partially changed the spool");
    writer.append_csv_packet(packet);
    std::filesystem::remove(csv);
    std::filesystem::create_symlink("/dev/full", csv);
    expect_error([&] { writer.write({packet}, 1000, 10); });
    require(std::filesystem::file_size(spool) > 16, "failed CSV write deleted the recovery spool");
    std::filesystem::remove(csv);
    writer.write({packet}, 1000, 10);
    require(!std::filesystem::exists(spool), "successful CSV export retained the spool");
    std::ifstream csv_input(csv);
    const std::string csv_text((std::istreambuf_iterator<char>(csv_input)), {});
    require(csv_text.find("1.000000000,3.000000000") != std::string::npos,
        "CSV retry lost channel samples");
    writer.initialize_csv(2, false);
    std::ofstream(spool, std::ios::binary | std::ios::app).put('x');
    expect_error([&] { writer.write({}, 1000, 10); });
    require(std::filesystem::exists(spool), "truncated packet header deleted the spool");
    writer.initialize_csv(2, false);
    const std::array<std::uint64_t, 4> corrupt_packet{0, 2, 0xffffffffffffffffULL, 0};
    std::ofstream(spool, std::ios::binary | std::ios::app).write(
        reinterpret_cast<const char*>(corrupt_packet.data()), sizeof(corrupt_packet));
    expect_error([&] { writer.write({}, 1000, 10); });
    require(std::filesystem::exists(spool), "oversized packet count deleted the spool");
}

void test_asset_reload_preserves_data(const Workspace& workspace) {
    const auto save = [&](const char* name, float sample) {
        return save_bundle(workspace, name, {.traces = {
            {.frequency_hz = {1}, .s21 = {{sample, 0}}}}});
    };
    const auto open = save("open.bin", 1);
    const auto nan = save("nan.bin", std::numeric_limits<float>::quiet_NaN());
    preprocessing::S21CalibrationBundle s21_calibration;
    s21_calibration.load(save("through.bin", 2));
    expect_error([&] { s21_calibration.load(nan); });
    const std::array<float, 1> frequency{1};
    std::array<ipc::Complex32, 1> samples{{{6, 8}}};
    s21_calibration.apply({}, frequency, samples);
    require(samples[0].re == 3 && samples[0].im == 4, "failed S21 reload changed previous calibration");
    const std::array<float, 1> nan_axis{std::numeric_limits<float>::quiet_NaN()};
    expect_error([&] { s21_calibration.apply({}, nan_axis, samples); });
    preprocessing::S21ReferenceBundle reference;
    reference.load(open, s21_calibration, {{}});
    expect_error([&] { reference.load(nan, s21_calibration, {{}}); });
    ipc::SweepTraceBlock trace{.frequency_hz = {1}, .s21 = {{2, 0}}};
    reference.apply(trace);
    require(trace.s21[0].re == 1.5F, "failed reference reload changed the calibrated reference");
}

void test_object_calibration(const Workspace& workspace) {
    const ipc::SweepTraceBlock first{.combo = {7, 3}, .frequency_hz = {1e9F, 2e9F},
        .s21 = {{2, 3}, {4, 5}}, .capture_start_ns = 5, .capture_end_ns = 15};
    const ipc::SweepTraceBlock second{.combo = {1, 9}, .frequency_hz = {3e9F, 4e9F, 5e9F},
        .s21 = {{6, 7}, {8, 9}, {10, 11}}};
    auto factors_first = first;
    factors_first.s21 = {{0, 2}, {2, 0}};
    auto factors_second = second;
    factors_second.s21 = {{1, -1}, {-1, 0}, {0, 1}};
    preprocessing::S21ObjectCalibrationBundle correction;
    auto trace = first;
    correction.apply(trace);
    require(ipc::serialize_raw_collection({.traces = {trace}}) == ipc::serialize_raw_collection({.traces = {first}}),
        "disabled object calibration changed a trace");
    correction.load(save_bundle(workspace, "object.bin", {.traces = {factors_second, factors_first}}));
    correction.validate_combos({first.combo, second.combo});
    expect_error([&] { correction.validate_combos({{0, 0}}); });
    for (auto invalid : {first, second}) {
        invalid.combo = {0, 0};
        expect_error([&] { correction.apply(invalid); });
    }
    auto mismatch = second;
    mismatch.frequency_hz[1] += 1e8F;  // Same endpoints and count; interior grid differs.
    expect_error([&] { correction.apply(mismatch); });
    mismatch = second;
    mismatch.s21.pop_back();
    expect_error([&] { correction.apply(mismatch); });
    auto nonfinite = factors_first;
    nonfinite.s21[0].re = std::numeric_limits<float>::quiet_NaN();
    expect_error([&] { correction.load(save_bundle(workspace, "object_nan.bin", {.traces = {nonfinite}})); });
    expect_error([&] { correction.load(save_bundle(workspace, "object_duplicate.bin", {.traces = {factors_first, factors_first}})); });
    auto expected = first;
    expected.s21 = {{-6, 4}, {8, 10}};
    trace = first;
    correction.apply(trace);
    require(ipc::serialize_raw_collection({.traces = {trace}}) == ipc::serialize_raw_collection({.traces = {expected}}),
        "object calibration changed timing, pair identity, or multiplication after a failed reload");
    trace = second;
    correction.apply(trace);
    require(trace.s21[0].re == 13 && trace.s21[0].im == 1 && trace.s21[1].re == -8 && trace.s21[1].im == -9 &&
            trace.s21[2].re == -11 && trace.s21[2].im == 10, "object calibration mixed pairs or frequency grids");
    trace = first;
    trace.s21[0] = {std::numeric_limits<float>::max(), std::numeric_limits<float>::max()};
    expect_error([&] { correction.apply(trace); });
    correction.load("");
    trace = first;
    correction.apply(trace);
    require(trace.s21[0].re == 2 && trace.s21[0].im == 3, "clearing object calibration left stale factors");
}

void test_object_calibration_pipeline(const Workspace& workspace) {
    const ipc::SweepTraceBlock trace{.combo = {7, 3}, .frequency_hz = {1e9F, 2e9F},
        .s21 = {{2, 4}, {6, 8}}, .capture_start_ns = 5, .capture_end_ns = 15};
    auto standard = trace;
    standard.s21 = {{2, 0}, {2, 0}};
    auto reference = trace;
    reference.s21 = {{1, 2}, {2, 2}};
    auto factors = trace;
    factors.s21 = {{0, 2}, {5, 1}};
    config::RunConfig config;
    config.preprocess.s21.calibration.bundle_path =
        save_bundle(workspace, "pipeline_through.bin", {.traces = {standard}});
    config.preprocess.s21.reference.bundle_path =
        save_bundle(workspace, "pipeline_reference.bin", {.traces = {reference}});
    config.run_combos = {trace.combo};
    config.preprocess.s21.object_calibration.bundle_path =
        save_bundle(workspace, "pipeline_object.bin", {.traces = {factors}});
    config.preprocess.notch = {.enabled = true, .bands_hz = {{2e9F, 2e9F}}, .taper_type = "hard"};
    RingName raw_name("_object_raw"), pre_name("_object_pre");
    auto raw_ring = ipc::ShmRing::open_or_create(raw_name.name, 2, 4096);
    auto pre_ring = ipc::ShmRing::open_or_create(pre_name.name, 2, 4096);
    preprocessing::DataPreprocessor preprocessor(config, raw_ring, pre_ring);
    require(raw_ring.push(ipc::serialize_raw_collection({.collection_id = 41, .capture_start_ns = 5,
        .capture_end_ns = 15, .traces = {trace}})), "test raw ring could not hold a sweep");
    std::atomic<bool> stop{false};
    std::exception_ptr error;
    std::jthread worker([&] { try { preprocessor.run(stop); } catch (...) { error = std::current_exception(); } });
    std::vector<std::uint8_t> bytes;
    const auto deadline = std::chrono::steady_clock::now() + std::chrono::seconds(2);
    while (bytes.empty() && std::chrono::steady_clock::now() < deadline) {
        (void)pre_ring.pop(bytes);
        std::this_thread::sleep_for(std::chrono::milliseconds(1));
    }
    stop.store(true);
    worker.join();
    if (error) { std::rethrow_exception(error); }
    require(!bytes.empty(), "object-corrected preprocessed collection was not published");
    const auto result = ipc::deserialize_preprocessed_collection(bytes);
    const auto& output = result.traces.at(0);
    require(result.collection_id == 41 && result.capture_start_ns == 5 && result.capture_end_ns == 15 &&
            output.combo == trace.combo && output.capture_start_ns == 5 && output.capture_end_ns == 15,
        "object calibration lost capture identity or timing");
    require(output.s21[0].re == -2 && output.s21[0].im == 1 && output.s21[1].re == 0 && output.s21[1].im == 0,
        "object calibration ran before existing preprocessing or was applied more than once");

}

void test_locator_packet_errors() {
    int sockets[2]{};
    require(::socketpair(AF_UNIX, SOCK_STREAM, 0, sockets) == 0, "socketpair failed");
    std::atomic<double> speed{0};
    std::atomic<std::int64_t> at_ns{0};
    locator::ClientSession client(sockets[0], "regression", 2, 1024);
    client.start(speed, at_ns);
    const auto send_json = [&](const std::string& json) {
        std::vector<std::uint8_t> bytes(8 + json.size());
        write_u32(bytes, 4, static_cast<std::uint32_t>(json.size()));
        std::memcpy(bytes.data() + 8, json.data(), json.size());
        const auto sent = ::send(sockets[1], bytes.data(), bytes.size(), MSG_NOSIGNAL);
        if (sent != static_cast<ssize_t>(bytes.size())) {
            throw std::runtime_error(std::string("send test packet failed: ") + std::strerror(errno));
        }
    };
    send_json("{\"vlc\":1e400}");
    send_json("{\"vlc\":1e308}");
    std::this_thread::sleep_for(std::chrono::milliseconds(50));
    require(at_ns.load() == 0 && speed.load() == 0, "invalid socket speed reached the processor");
    send_json("{\"vlc\":3.5}");
    const auto deadline = std::chrono::steady_clock::now() + std::chrono::seconds(2);
    while (at_ns.load() == 0 && std::chrono::steady_clock::now() < deadline) {
        std::this_thread::sleep_for(std::chrono::milliseconds(1));
    }
    require(speed.load() == 3.5 && at_ns.load() > 0, "locator stopped after oversized JSON number");
    client.request_stop();
    client.join();
    ::close(sockets[1]);
    require(client.has_exited(), "locator session did not finish both loops");
    locator::LocatorServerConfig config{.host = "127.0.0.1", .port = 0};
    locator::TcpServer server(config);
    for (unsigned iteration = 0; iteration < 30; ++iteration) { server.start(); server.stop(); }
}

void test_unread_tty_shutdown(const Workspace& workspace) {
    TtyProtocolWriter writer((workspace.path / "tty").string(), 160'000);
    const std::vector<std::uint16_t> words(80'000, 42);
    writer.enqueue_encoded_frames(words.data(), words.size() / 4U);
    std::this_thread::sleep_for(std::chrono::milliseconds(50));
    const auto start = std::chrono::steady_clock::now();
    writer.shutdown();
    require(std::chrono::steady_clock::now() - start < std::chrono::seconds(1),
        "unread tty blocked shutdown");
    writer.shutdown();
}

}  // namespace

int main(int argc, char** argv) {
    try {
        require(argc == 2, "Pass the simulator config fixture path");
        Workspace workspace;
        test_wire_format();
        test_configuration(argv[1], workspace);
        test_asset_reload_preserves_data(workspace);
        test_object_calibration(workspace);
        test_object_calibration_pipeline(workspace);
        test_ring();
        test_acquisition_identity();
        test_interruptible_wait();
        test_cosine_notch_taper();
        test_csv_failures(workspace);
        test_locator_packet_errors();
        test_unread_tty_shutdown(workspace);
        std::cout << "native regressions passed (10,000 decoder mutations; 20,000 concurrent ring frames)\n";
    } catch (const std::exception& error) {
        std::cerr << "native regression failed: " << error.what() << '\n';
        return 1;
    }
}