#include "fgc/Application.h"

#include "fgc/CalibrationRoutine.h"
#include "fgc/CaptureScheduler.h"
#include "fgc/CommandParser.h"
#include "fgc/DiagParser.h"
#include "fgc/DumpParser.h"
#include "fgc/HelpText.h"
#include "fgc/Paths.h"
#include "fgc/CameraMode.h"
#include "fgc/ICameraSource.h"
#include "fgc/IControlChannel.h"
#include "fgc/IEnvSensor.h"
#include "fgc/IImuSource.h"
#include "fgc/IMotorController.h"
#include "fgc/ImagePipeline.h"
#include "fgc/Logger.h"
#include "fgc/MtiImuSource.h"
#include "fgc/ScanGrid.h"
#include "fgc/SerialMotorController.h"
#include "fgc/TestReport.h"
#include "fgc/TestRunner.h"
#include "fgc/mock/MockCameraSource.h"
#include "fgc/mock/MockEnvSensor.h"
#include "fgc/mock/MockImuSource.h"
#include "fgc/mock/MockMotorController.h"
#include "fgc/mock/NullControlChannel.h"
#include "fgc/sensors/Sht41EnvSensor.h"
#include "fgc/ui/HeadlessUi.h"
#include "fgc/ui/IUserInterface.h"
#include "fgc/ui/UiSnapshot.h"

#include <algorithm>
#include <atomic>
#include <cctype>
#include <chrono>
#include <cmath>
#include <csignal>
#include <cstdio>
#include <cstdlib>
#include <filesystem>
#include <fstream>
#include <memory>
#include <mutex>
#include <queue>
#include <sstream>
#include <string>
#include <thread>

#if FGC_WITH_MQTT
#include "fgc/MqttControlChannel.h"
#endif
#if FGC_WITH_VIMBA
#include "fgc/VimbaCameraSource.h"
#endif
#if FGC_WITH_TUI
#include "fgc/ui/TuiUi.h"
#endif

namespace fgc {

namespace {

// Set by SIGINT/SIGTERM so the control loop exits cleanly and tears the camera down
// (StopContinuousImageAcquisition + Close). Without this, a Ctrl-C / kill / systemd
// stop skips teardown and leaves the camera acquiring - which wedges it so the NEXT
// run gets no frames. Only an atomic flag is set here (async-signal-safe).
std::atomic<bool> g_shutdown_requested{false};
void handleShutdownSignal(int) { g_shutdown_requested.store(true); }

long long nowEpochMs() {
    return std::chrono::duration_cast<std::chrono::milliseconds>(
               std::chrono::system_clock::now().time_since_epoch())
        .count();
}

// True if `dir` can be created and a probe file written there. A successful
// create_directories alone isn't enough (the dir may exist read-only), so we
// actually write+remove a probe file.
bool outputDirWritable(const std::string& dir) {
    namespace fs = std::filesystem;
    std::error_code ec;
    fs::create_directories(dir, ec);
    if (ec) return false;
    const fs::path probe = fs::path(dir) / ".fgc_write_test";
    std::ofstream f(probe);
    if (!f.good()) return false;
    f.close();
    fs::remove(probe, ec);
    return true;
}

// Human-readable list of the enabled wire-trace categories, for echoing back.
std::string traceNames(unsigned mask) {
    if (mask == 0) return "none";
    std::string out;
    const std::pair<LogCat, const char*> all[] = {
        {LogCat::Serial, "serial"}, {LogCat::Mqtt, "mqtt"},
        {LogCat::Camera, "camera"}, {LogCat::Control, "control"},
    };
    for (const auto& [cat, name] : all) {
        if (mask & static_cast<unsigned>(cat)) {
            if (!out.empty()) out += ',';
            out += name;
        }
    }
    return out;
}

// Build the expanded-view ImuConfigView from the device's decoded config.
ImuConfigView formatImuConfig(const ImuDeviceConfig& c) {
    ImuConfigView v;
    v.present = true;
    v.product_code = c.product_code.empty() ? "—" : c.product_code;
    if (c.has_device_id) {
        char b[16];
        std::snprintf(b, sizeof(b), "0x%08X", c.device_id);
        v.device_id = b;
    } else {
        v.device_id = "—";
    }
    v.firmware = c.firmware.empty() ? "—" : c.firmware;

    if (c.has_output_mode) {
        std::string m;
        auto add = [&](bool on, const char* name) {
            if (on) { if (!m.empty()) m += " · "; m += name; }
        };
        add(c.out_temperature, "Temp");
        add(c.out_calibrated, "Calibrated");
        add(c.out_orientation, "Orientation");
        add(c.out_auxiliary, "Auxiliary");
        add(c.out_status, "Status");
        v.output_mode = m.empty() ? "—" : m;
    } else {
        v.output_mode = "—";
    }

    if (c.has_output_settings) {
        v.output_settings = c.orientation_mode + " · " + c.timestamp_mode + " · " + c.data_format;
        std::string ch;
        if (c.acc_enabled) ch += "acc ";
        if (c.gyr_enabled) ch += "gyr ";
        if (c.mag_enabled) ch += "mag";
        v.channels = ch.empty() ? "none" : ch;
    } else {
        v.output_settings = "—";
        v.channels = "—";
    }

    if (c.has_period && c.sample_rate_hz > 0) {
        char b[24];
        std::snprintf(b, sizeof(b), "%.0f Hz", c.sample_rate_hz);
        v.sample_rate = b;
    } else {
        v.sample_rate = "—";
    }

    // XKF profiles: list every available profile by name (no numeric IDs) and
    // flag the active one (matched by profile type).
    for (const auto& p : c.available_profiles) {
        ImuProfileView pv;
        pv.name = p.label.empty() ? "(unnamed)" : p.label;
        pv.selected = c.has_scenario && p.type == c.scenario_type;
        v.xkf_profiles.push_back(std::move(pv));
    }
    // If the device reported the active profile but not the full list, still show
    // the one in use (by its resolved label, when known).
    if (v.xkf_profiles.empty() && c.has_scenario && !c.scenario_label.empty())
        v.xkf_profiles.push_back({c.scenario_label, true});
    return v;
}

}  // namespace

struct Application::Impl {
    Impl(AppConfig c, RuntimeOptions o) : cfg(std::move(c)), opts(std::move(o)) {}

    AppConfig      cfg;
    RuntimeOptions opts;

    std::unique_ptr<IControlChannel>  channel;
    std::unique_ptr<IMotorController> motor;
    std::unique_ptr<ICameraSource>    camera;
    // Camera modes, loaded once at startup and kept so a live switch needs no disk
    // access. `camera_mode` is the active one.
    std::map<std::string, CameraMode> camera_modes;
    std::string                       camera_mode;
    std::unique_ptr<IImuSource>       imu;
    std::unique_ptr<IEnvSensor>       env;
    std::unique_ptr<ImagePipeline>    pipeline;
    std::unique_ptr<CaptureScheduler> scheduler;
    std::unique_ptr<IUserInterface>   ui;
    std::unique_ptr<CalibrationRoutine> calib;
    std::unique_ptr<TestRunner>       tester;
    unsigned                          last_diag_seq = 0;
    ScanGrid                          grid;  // outlives scheduler (holds a reference to it)
    std::string                       scan_load_error_;  // non-empty if grid_file failed to load

    // Persisted last-results for the TUI activity strip (survive in the log churn).
    bool                     diag_running_ = false;
    std::chrono::steady_clock::time_point diag_started_;
    std::vector<std::string> last_diag_summary;
    long long                last_diag_ts = 0;   // epoch ms
    bool                     last_diag_pass = false;
    DiagResultView           last_diag_view;     // per-axis worst tracking error
    // Rising-edge latches for the live encoder-error WARN (avoid 100Hz spam).
    bool                     yaw_track_over_ = false;
    bool                     pitch_track_over_ = false;
    CalibResultView          last_calib_view;
    std::vector<std::string> last_calib_summary;
    long long                last_calib_ts = 0;   // epoch ms
    bool                     calib_save_pending_ = false;  // awaiting y/n to persist to config

    // Hardware self-test (`test` command) results, for the activity strip.
    TestResultView           last_test_view;
    std::vector<std::string> last_test_summary;
    long long                last_test_ts = 0;     // epoch ms
    bool                     last_test_pass = false;
    std::string              last_test_report_path;  // promoted by `test baseline`

    // Procedure lock-out: while a long op runs, interfering commands are ignored
    // and Esc cancels. Homing runs on the control thread (blocking), so it uses
    // these flags directly; calibration/test run on their own threads.
    std::atomic<bool>        homing_active_{false};
    std::atomic<bool>        cancel_procedure_{false};
    double                   test_drift_warn_ = 15.0;  // % (from the running profile)
    bool                     test_drift_gate_ = false;
    mutable ImuConfigView    imu_config_view_;     // formatted MTi config (read once)
    mutable bool             imu_config_done_ = false;
    mutable long long        last_env_published_ts_ = 0;  // gate MQTT publish to one per fresh sample

    std::atomic<bool>       running{true};
    std::mutex              cmd_mutex;
    std::queue<std::string> cmd_queue;

    std::chrono::steady_clock::time_point start_time;
    std::mutex                            snapshot_mutex;
    UiSnapshot                            latest_snapshot;

    std::string statusTopicTower() const { return cfg.general.tower_name; }

    std::unique_ptr<IControlChannel> makeChannel() {
        bool want = opts.use_mqtt.value_or(cfg.features.enable_mqtt);
#if FGC_WITH_MQTT
        if (want) {
            return std::make_unique<MqttControlChannel>(cfg.network.brokerUri(),
                                                        cfg.general.tower_name,
                                                        cfg.network.mqtt_user,
                                                        cfg.network.mqtt_pw);
        }
#else
        if (want) LOG_WARN << "MQTT requested but binary built without MQTT; using null channel";
#endif
        return std::make_unique<NullControlChannel>();
    }

    std::unique_ptr<IMotorController> makeMotor() {
        bool mock = opts.mock_serial.value_or(cfg.features.mock_serial);
        if (mock) return std::make_unique<MockMotorController>();
        return std::make_unique<SerialMotorController>(cfg.serial.device, cfg.serial.baud);
    }

    std::unique_ptr<IImuSource> makeImu() {
        if (!cfg.features.enable_imu) return nullptr;  // sensors panel stays "pending"
        if (cfg.features.mock_imu) return std::make_unique<MockImuSource>();
        if (cfg.imu.device.empty()) {
            LOG_WARN << "IMU enabled but [IMU] device is empty; disabling IMU";
            return nullptr;
        }
        return std::make_unique<MtiImuSource>(cfg.imu.device, cfg.imu.baud);
    }

    std::unique_ptr<IEnvSensor> makeEnv() {
        // --mock-env implies enable_env: the sensor is off by default, so without
        // that the flag would silently do nothing.
        const bool force_mock = opts.mock_env.value_or(false);
        if (!cfg.features.enable_env && !force_mock)
            return nullptr;  // sensors panel stays "pending"
        if (force_mock || cfg.features.mock_env) return std::make_unique<MockEnvSensor>();
        if (cfg.env.i2c_device.empty()) {
            LOG_WARN << "Env sensor enabled but [Env] i2c_device is empty; disabling";
            return nullptr;
        }
        return std::make_unique<Sht41EnvSensor>(cfg.env.i2c_device,
                                                static_cast<uint8_t>(cfg.env.i2c_addr),
                                                std::chrono::milliseconds(cfg.env.period_ms));
    }

    std::unique_ptr<ICameraSource> makeCamera() {
        bool mock = opts.mock_camera.value_or(cfg.features.mock_camera);
#if !FGC_WITH_VIMBA
        if (!mock) {
            LOG_WARN << "Camera requested but binary built without Vimba X; using mock camera";
            mock = true;
        }
#endif
        if (mock) {
            int count = cfg.camera.ids.empty() ? 1 : static_cast<int>(cfg.camera.ids.size());
            return std::make_unique<MockCameraSource>(count);
        }
#if FGC_WITH_VIMBA
        auto cam = std::make_unique<VimbaCameraSource>(cfg.camera);
        cam->setInitialMode(camera_modes.at(camera_mode));
        return cam;
#else
        return std::make_unique<MockCameraSource>(1);
#endif
    }

    // Load every mode file up front, so a typo in a mode nobody is using today
    // still fails at startup rather than the first time someone switches to it.
    void loadModes() {
        camera_modes = fgc::loadCameraModes(cfg.camera.mode_dir);
        if (camera_modes.find(cfg.camera.mode) == camera_modes.end()) {
            std::string known;
            for (const auto& [name, m] : camera_modes) known += (known.empty() ? "" : ", ") + name;
            throw std::runtime_error("Camera.mode '" + cfg.camera.mode + "' has no " +
                                     cfg.camera.mode + ".ini in " + cfg.camera.mode_dir +
                                     " (available: " + known + ")");
        }
        camera_mode = cfg.camera.mode;
        LOG_INFO << "camera modes: " << camera_modes.size() << " from " << cfg.camera.mode_dir
                 << "; active '" << camera_mode << "'";
    }

    // Switch the live camera mode by name. Returns false (and warns) if unknown.
    bool applyMode(const std::string& name) {
        auto it = camera_modes.find(name);
        if (it == camera_modes.end()) {
            std::string known;
            for (const auto& [n, m] : camera_modes) known += (known.empty() ? "" : ", ") + n;
            LOG_WARN << "unknown camera mode '" << name << "' (available: " << known << ')';
            return false;
        }
        if (camera) camera->setMode(it->second);
        camera_mode = name;
        if (scheduler)
            scheduler->setSettleWait(it->second.settle_wait_ms, it->second.frame_timeout_ms);
        LOG_INFO << "camera mode -> " << name << " (" << it->second.description << ')';
        return true;
    }

    std::unique_ptr<IUserInterface> makeUi() {
        bool want = opts.use_tui.value_or(cfg.ui.enable_tui);
#if FGC_WITH_TUI
        if (want) return std::make_unique<TuiUi>();
#else
        if (want) LOG_WARN << "TUI requested but binary built without TUI support; using headless console";
#endif
        return std::make_unique<HeadlessUi>();
    }

    // Read live state (on the control thread) into a plain snapshot the UI can
    // copy and render without touching the logic objects. The log pane is filled
    // by the UI from its own ring buffer, so it is left empty here.
    UiSnapshot buildSnapshot() const {
        UiSnapshot s;

        const bool mock_serial = opts.mock_serial.value_or(cfg.features.mock_serial);
        s.header.tower     = cfg.general.tower_name;
        s.header.build     = "dev";
        s.header.uptime_ms = std::chrono::duration_cast<std::chrono::milliseconds>(
                                 std::chrono::steady_clock::now() - start_time).count();
        s.header.live      = !mock_serial;

        // --- Gimbal ---
        MotorTelemetry t = motor->telemetry();
        s.gimbal.present       = motor->connected();
        s.gimbal.pitch_present = t.pitch_present;
        auto fillAxis = [](AxisView& v, const char* label, const AxisTelemetry& a,
                           const AxisMap& map, long target_counts) {
            v.label      = label;
            v.state      = a.state;
            v.deg        = map.toDeg(a.xenc);
            v.xactual    = a.xactual;
            v.xenc       = a.xenc;
            v.enc_err    = a.xactual - a.xenc;   // live tracking error (counts)
            v.target_deg = map.toDeg(target_counts);
            v.sg         = a.sg;
            v.cs         = a.cs;
            v.pwm        = a.pwm;
            v.drv_status = a.drv_status;
            v.moving     = a.moving();
            v.standstill = a.standstill;
            v.stall      = a.stall;
            v.overtemp   = a.overtemp;
            v.endstop_l  = a.endstop_l;
            v.endstop_r  = a.endstop_r;
        };
        long yaw_tgt   = scheduler ? scheduler->yawTargetCounts()   : 0;
        long pitch_tgt = scheduler ? scheduler->pitchTargetCounts() : 0;
        fillAxis(s.gimbal.yaw,   "YAW",   t.yaw,   cfg.geometry.yaw,   yaw_tgt);
        fillAxis(s.gimbal.pitch, "PITCH", t.pitch, cfg.geometry.pitch, pitch_tgt);

        // Homing travel limits come from the last firmware dump (lim_neg/lim_pos);
        // convert the endstop counts to degrees via the per-axis geometry.
        DumpData dd = parseDump(motor->lastDump());
        if (dd.valid) {
            auto fillLimits = [](AxisView& v, const DumpAxis& a, const AxisMap& map) {
                v.has_limits  = true;
                v.lim_neg     = a.lim_neg;
                v.lim_pos     = a.lim_pos;
                v.lim_neg_deg = map.toDeg(a.lim_neg);
                v.lim_pos_deg = map.toDeg(a.lim_pos);
                v.has_track            = true;
                v.hold_corrections     = a.hold_corrections;
                v.hold_peak_dev        = a.hold_peak_dev;
                v.hold_cumulative_dev  = a.hold_cumulative_dev;
            };
            for (const auto& a : dd.axes) {
                if (a.axis == 'Y') fillLimits(s.gimbal.yaw,   a, cfg.geometry.yaw);
                else if (a.axis == 'P') fillLimits(s.gimbal.pitch, a, cfg.geometry.pitch);
            }
        }

        // --- Sensors: MTi (orientation) + SHT41 (ambient), each live if present ---
        s.sensors = pendingSensorsView();
        if (imu) {
            auto fmt1 = [](float v) {
                char b[24];
                std::snprintf(b, sizeof(b), "%.1f", v);
                return std::string(b);
            };
            auto setField = [&](SensorField& f, const std::string& v) {
                f.value   = v;
                f.present = true;
            };
            // Device configuration (read once at startup): format and cache.
            if (!imu_config_done_) {
                if (auto c = imu->config()) {
                    imu_config_view_ = formatImuConfig(*c);
                    imu_config_done_ = true;
                }
            }
            s.imu.config = imu_config_view_;
            if (auto m = imu->sample()) {
                // Full reading for the expanded view.
                s.imu.present        = true;
                s.imu.roll_deg       = m->roll_deg;
                s.imu.pitch_deg      = m->pitch_deg;
                s.imu.yaw_deg        = m->yaw_deg;
                for (int i = 0; i < 3; ++i) {
                    s.imu.acc[i] = m->acc[i];
                    s.imu.gyr[i] = m->gyr[i];
                    s.imu.mag[i] = m->mag[i];
                }
                s.imu.temp_c         = m->temp_c;
                s.imu.sample_counter = m->sample_counter;
                // Compact MTi subsection: Roll/Pitch/Yaw only. The internal temp
                // stays in s.imu (expanded view) so the main window's single
                // temperature is unambiguously the SHT41's ambient one.
                auto& g = s.sensors.imu;
                g.present = true;
                g.status  = "live";
                if (g.fields.size() >= 3) {
                    setField(g.fields[0], fmt1(m->roll_deg));
                    setField(g.fields[1], fmt1(m->pitch_deg));
                    setField(g.fields[2], fmt1(m->yaw_deg));
                }
            } else {
                s.sensors.imu.status = "no fix";
            }
        }

        if (env) {
            auto fmt1 = [](float v) {
                char b[24];
                std::snprintf(b, sizeof(b), "%.1f", v);
                return std::string(b);
            };
            auto setField = [&](SensorField& f, const std::string& v) {
                f.value   = v;
                f.present = true;
            };
            // Identity and bus config are set whether or not a sample is available,
            // so the expanded view can still say what the sensor is and where it
            // should be when it goes quiet.
            s.env.enabled    = true;
            s.env.mock       = opts.mock_env.value_or(cfg.features.mock_env);
            s.env.name       = env->name();
            s.env.i2c_device = cfg.env.i2c_device;
            s.env.i2c_addr   = cfg.env.i2c_addr;
            s.env.period_ms  = cfg.env.period_ms;
            if (auto m = env->sample()) {
                s.env.present      = true;
                s.env.temp_c       = m->temp_c;
                s.env.humidity_pct = m->humidity_pct;
                s.env.timestamp_ms = m->timestamp_ms;

                auto& g = s.sensors.env;
                g.present = true;
                g.status  = "live";
                if (g.fields.size() >= 2) {
                    setField(g.fields[0], fmt1(m->temp_c));
                    setField(g.fields[1], fmt1(m->humidity_pct));
                }
                // Publish once per fresh sample, not every ~10ms control-loop tick.
                if (channel && m->timestamp_ms != last_env_published_ts_) {
                    last_env_published_ts_ = m->timestamp_ms;
                    EnvEvent ev;
                    ev.tower        = cfg.general.tower_name;
                    ev.temp_c       = m->temp_c;
                    ev.humidity_pct = m->humidity_pct;
                    ev.timestamp_ms = m->timestamp_ms;
                    channel->publishEnv(ev);
                }
            } else {
                s.sensors.env.status = "no fix";
            }
        }

        // --- Camera / capture ---
        s.capture.present      = true;
        s.capture.active       = scheduler && scheduler->captureActive();
        s.capture.image_rate   = scheduler ? scheduler->imageRate() : 0.0;
        s.capture.camera_count = camera ? camera->cameraCount() : 0;
        s.capture.labels       = cfg.camera.labels;
        // Static imaging + encoding config, for the expanded camera view.
        {
            auto& cc = s.capture.config;
            cc.mock              = opts.mock_camera.value_or(cfg.features.mock_camera);
            cc.ids               = cfg.camera.ids;
            cc.mode              = camera_mode;
            if (auto it = camera_modes.find(camera_mode); it != camera_modes.end()) {
                cc.mode_desc      = it->second.description;
                cc.settle_wait_ms = it->second.settle_wait_ms;
            }
            cc.modes_available.clear();
            for (const auto& [name, m] : camera_modes) cc.modes_available.push_back(name);
            cc.jxl_distance      = cfg.camera.jxl_distance;
            cc.jxl_effort        = cfg.camera.jxl_effort;
            cc.rotation_deg      = cfg.camera.rotation_deg;
            cc.output_dir        = cfg.paths.output_dir;
        }
        // Live per-camera identity/telemetry/stats.
        s.capture.devices.clear();
        if (camera) {
            for (const auto& d : camera->deviceInfo()) {
                CameraDeviceView v;
                v.id = d.id; v.model = d.model; v.serial = d.serial; v.streaming = d.streaming;
                v.width = d.width; v.height = d.height; v.payload_bytes = d.payload_bytes;
                v.exposure_us = d.exposure_us; v.gain_db = d.gain_db;
                v.temperature_c = d.temperature_c; v.actual_fps = d.actual_fps;
                v.frames_delivered = d.frames_delivered; v.frames_dropped = d.frames_dropped;
                v.restarts = d.restarts;
                s.capture.devices.push_back(std::move(v));
            }
        }
        s.capture.images_saved = pipeline ? pipeline->imagesSaved() : 0;

        // Defined scan grid + live cursor (read on the control thread, same as the
        // scheduler that mutates it, so no locking is needed).
        s.capture.scan_from_file = !cfg.scan.grid_file.empty();
        s.capture.scan_pitch     = t.pitch_present;
        s.capture.scan_error     = scan_load_error_;
        s.capture.scan_grid.clear();
        const auto& pts = grid.points();
        s.capture.scan_grid.reserve(pts.size());
        for (std::size_t i = 0; i < pts.size(); ++i)
            s.capture.scan_grid.push_back({pts[i].yaw_deg, pts[i].pitch_deg, i == grid.index()});
        if (pipeline) {
            if (auto ev = pipeline->lastEvent()) {
                s.capture.has_last         = true;
                s.capture.last_label       = ev->camera;
                s.capture.last_heading_deg = ev->heading_decideg / 10.0;
                s.capture.last_pitch_deg   = ev->pitch_decideg / 10.0;
                s.capture.last_ts_ms       = ev->timestamp_ms;
            }
        }

        // --- Connectivity ---
        s.conn.mqtt_enabled     = opts.use_mqtt.value_or(cfg.features.enable_mqtt);
        s.conn.mqtt_connected   = channel && channel->connected();
        s.conn.broker           = cfg.network.brokerUri();
        s.conn.tower            = cfg.general.tower_name;
        s.conn.control_code     = scheduler ? scheduler->controlCode() : 0;
        s.conn.target_heading   = scheduler ? scheduler->targetHeading() : "0";
        s.conn.last_status_code = s.conn.control_code;  // echoed back as status

        // --- Diagnostics (last firmware DUMP) ---
        s.dump.text = motor->lastDump();
        s.dump.has  = !s.dump.text.empty();

        // --- Activity strip + last calibration ---
        s.calib = last_calib_view;
        s.calib.pitch_present = s.gimbal.pitch_present || s.calib.pitch_present;
        s.diag = last_diag_view;
        s.test = last_test_view;
        fillActivity(s);
        return s;
    }

    // The currently-running special op (priority: calib > diag > homing > capture)
    // plus the most recent persisted result, for the activity strip.
    void fillActivity(UiSnapshot& s) const {
        ActivityView& a = s.activity;

        if (tester && tester->running()) {
            TestProgress p = tester->progress();
            a.active = true;
            a.title  = "TESTING";
            a.status = p.section.empty()
                           ? "running hardware self-test…"
                           : p.section + "  " + std::to_string(p.step) + "/" +
                                 std::to_string(p.total) + " — " + p.phase;
        } else if (calib && calib->running()) {
            CalibProgress p = calib->progress();
            a.active = true;
            a.title  = "CALIBRATING";
            std::string axis = (p.axis == 'P') ? "PITCH" : (p.axis == 'Y') ? "YAW" : "";
            a.status = axis.empty() ? p.phase
                     : axis + " step " + std::to_string(p.step) + "/" +
                           std::to_string(p.total) + " — " + p.phase;
        } else if (diag_running_) {
            a.active = true;
            a.title  = "DIAGNOSTICS";
            a.status = "running motor self-test…";
        } else if (s.gimbal.yaw.state == AxisState::Homing ||
                   (s.gimbal.pitch_present && s.gimbal.pitch.state == AxisState::Homing)) {
            a.active = true;
            a.title  = "HOMING";
            a.status = "finding endstops…";
        } else if (scheduler && scheduler->captureActive()) {
            a.active = true;
            a.title  = "CAPTURE";
            const char* phase = scheduler->moving() ? "moving" : "dwell";
            if (scheduler->controlCode() == 1) {
                a.status = "directed → heading " + scheduler->targetHeading() + "°  ·  " +
                           (scheduler->moving() ? "moving" : "holding");
            } else if (!grid.empty()) {
                const ScanPoint& p = grid.current();
                std::string coord = "yaw " + formatDegrees(p.yaw_deg);
                if (s.capture.scan_pitch) coord += " / pitch " + formatDegrees(p.pitch_deg);
                a.status = "waypoint " + std::to_string(grid.index() + 1) + "/" +
                           std::to_string(grid.size()) + "  ·  " + coord + "  ·  " + phase;
            } else {
                a.status = "no scan grid — auto-sweep disabled";
            }
        }

        // A running procedure is cancelable with Esc.
        a.cancelable = procedureBusy();

        // Persisted result: the most recent of last test / calibration / diagnostics.
        const long long now = nowEpochMs();
        if (last_test_ts >= last_calib_ts && last_test_ts >= last_diag_ts && last_test_ts) {
            a.has_result   = true;
            a.result_title = std::string("Test ") + (last_test_pass ? "PASS" : "FAIL") +
                             " · " + formatTimeAgo(now, last_test_ts);
            a.result       = last_test_summary;
            a.result_color = last_test_pass ? UiColor::Green : UiColor::Red;
        } else if (last_calib_ts || last_diag_ts) {
            const bool calib_newer = last_calib_ts >= last_diag_ts;
            a.has_result = true;
            if (calib_newer) {
                a.result_title = "Calibration · " + formatTimeAgo(now, last_calib_ts);
                a.result       = last_calib_summary;
                a.result_color = last_calib_view.has &&
                                 last_calib_view.yaw.ok ? UiColor::Green : UiColor::Yellow;
            } else {
                a.result_title = std::string("Diagnostics ") +
                                 (last_diag_pass ? "PASS" : "FAIL") + " · " +
                                 formatTimeAgo(now, last_diag_ts);
                a.result       = last_diag_summary;
                a.result_color = last_diag_pass ? UiColor::Green : UiColor::Red;
            }
        }

        // Pending yes/no: persist the just-applied calibration as the new default?
        if (calib_save_pending_)
            a.prompt = "Save this calibration to config as the new default?  (y / n)";
    }

    void publishSnapshot() {
        UiSnapshot s = buildSnapshot();
        std::lock_guard<std::mutex> lock(snapshot_mutex);
        latest_snapshot = std::move(s);
    }

    // Warn (once per excursion) when an axis's live encoder error |xactual-xenc|
    // crosses the configured limit, so positional slip is visible in the log
    // without watching the gimbal view. Hysteresis re-arms at 75% of the limit.
    void checkTrackingError() {
        const long limit = cfg.enc_error_warn_counts;
        if (limit <= 0) return;  // disabled
        MotorTelemetry t = motor->telemetry();
        auto check = [&](const char* axis, const AxisTelemetry& a, bool present, bool& over) {
            if (!present) return;
            const long err = std::labs(a.xactual - a.xenc);
            if (!over && err > limit) {
                over = true;
                LOG_WARN << "encoder tracking error on " << axis << ": " << (a.xactual - a.xenc)
                         << " counts (limit " << limit << ")";
            } else if (over && err < limit * 3 / 4) {
                over = false;
            }
        };
        check("yaw", t.yaw, true, yaw_track_over_);
        check("pitch", t.pitch, t.pitch_present, pitch_track_over_);
    }

    void runInitSequence() {
        using namespace std::chrono_literals;
        LOG_INFO << "Running gimbal init sequence (enable + home)";
        // Mark homing active so interfering commands are ignored and Esc cancels.
        // This blocks the control thread, so commands are drained+discarded here.
        homing_active_ = true;
        cancel_procedure_ = false;
        struct ClearHoming {
            std::atomic<bool>& flag;
            ~ClearHoming() { flag = false; }
        } clear_homing{homing_active_};

        motor->sendCommand("ENABLE Y");
        motor->sendCommand("ENABLE P");
        motor->sendCommand("HOME");  // homes all axes; firmware runs it non-blocking

        auto allReady = [](const MotorTelemetry& t) {
            return t.yaw.ready() && (!t.pitch_present || t.pitch.ready());
        };

        // The axes may already be READY (EEPROM fast-path), so first wait briefly
        // for homing to actually begin (an axis leaves READY) before waiting for
        // it to finish - otherwise we'd see the residual READY and return early.
        const auto t0 = std::chrono::steady_clock::now();
        while (running && !cancel_procedure_ && std::chrono::steady_clock::now() < t0 + 3s) {
            std::this_thread::sleep_for(100ms);
            drainAndDiscardCommands();  // ignore moves/etc queued during homing
            publishSnapshot();  // keep the TUI's gimbal panel live during homing
            if (!allReady(motor->telemetry())) break;  // homing started
        }

        // Wait for completion (both axes READY again) or the homing timeout.
        bool homed = false;
        const auto deadline = std::chrono::steady_clock::now() + 65s;
        while (running && !cancel_procedure_ && std::chrono::steady_clock::now() < deadline) {
            std::this_thread::sleep_for(250ms);
            drainAndDiscardCommands();
            publishSnapshot();  // keep the TUI's gimbal panel live during homing
            MotorTelemetry t = motor->telemetry();
            if (t.yaw.state == AxisState::Error ||
                (t.pitch_present && t.pitch.state == AxisState::Error)) {
                LOG_WARN << "Homing reported ERROR state; check the gimbal";
                break;
            }
            if (allReady(t)) {
                LOG_INFO << "Gimbal homed (both axes READY)";
                homed = true;
                break;
            }
        }
        if (cancel_procedure_) {
            LOG_WARN << "Homing cancelled";
            motor->sendCommand("STOP ALL");
            return;
        }
        // Re-anchor the yaw zero to an endstop now that the homed limits are known.
        if (homed) applyYawHomeZero();
        // Production move speeds for subsequent MOVE commands.
        motor->sendCommand("SPEED Y 50000");
        motor->sendCommand("SPEED P 150000");
        LOG_INFO << "Gimbal init finished";
    }

    // With [Motor] yaw_home_zero = low|high, redefine the yaw degree origin from
    // the freshly homed endstops: the chosen endstop becomes 0 deg and degrees
    // rise toward the other limit (forced positive, so it lands near +360). The
    // counts_per_deg magnitude is kept from config/calibration; only the zero and
    // sign change, so the yaw zero is fixed by homing and never needs a separate
    // calibration. Pitch is left untouched.
    void applyYawHomeZero() {
        using namespace std::chrono_literals;
        if (cfg.yaw_home_zero == YawHomeZero::Off) return;

        // The homed limits live in the firmware DUMP; pull a fresh one and wait
        // briefly for it to arrive with yaw endstops populated.
        motor->sendCommand("DUMP");
        long lo = 0, hi = 0, margin = 0;
        bool got = false;
        const auto deadline = std::chrono::steady_clock::now() + 3s;
        while (running && std::chrono::steady_clock::now() < deadline) {
            std::this_thread::sleep_for(100ms);
            publishSnapshot();
            DumpData dd = parseDump(motor->lastDump());
            if (dd.valid)
                for (const auto& a : dd.axes)
                    if (a.axis == 'Y' && a.lim_pos != a.lim_neg) {
                        lo = a.lim_neg; hi = a.lim_pos; margin = a.soft_margin; got = true;
                    }
            if (got) break;
        }
        if (!got) {
            LOG_WARN << "yaw home-zero: no homed yaw limits in dump; keeping configured zero";
            return;
        }
        if (margin <= 0)
            LOG_WARN << "yaw home-zero: firmware reported no soft_margin (update firmware); "
                        "anchoring at the hard homing limit instead of the soft limit";

        const double mag = std::fabs(cfg.geometry.yaw.counts_per_deg);
        if (mag < 1e-9) {
            LOG_WARN << "yaw home-zero: yaw_counts_per_deg ~0; calibrate first; keeping zero";
            return;
        }
        // Anchor at the soft limits (the actual reachable travel), not the hard
        // homing endstops, so the rightmost *reachable* position reads exactly 0.
        const long   lo_soft   = lo + margin;
        const long   hi_soft   = hi - margin;
        const bool   zero_high = (cfg.yaw_home_zero == YawHomeZero::High);
        const long   zero_cnt  = zero_high ? hi_soft : lo_soft;
        const long   other_cnt = zero_high ? lo_soft : hi_soft;
        // Sign so the other endstop sits at positive degrees (rises toward ~+360).
        const double cpd       = (other_cnt > zero_cnt) ? mag : -mag;
        const double range_deg = std::fabs(static_cast<double>(other_cnt - zero_cnt)) / mag;

        AxisMap& y       = cfg.geometry.yaw;
        y.zero_count     = zero_cnt;
        y.counts_per_deg = cpd;
        y.min_deg        = 0.0;
        y.max_deg        = range_deg;
        if (scheduler) scheduler->setGeometry(cfg.geometry);  // re-target the scan with it

        LOG_INFO << "yaw zero anchored at " << (zero_high ? "high" : "low")
                 << "-count endstop: 0.0.." << range_deg << " deg (zero_count=" << zero_cnt
                 << ", counts_per_deg=" << cpd << ")";
    }

    void startCapture() {
        // The scheduler arms regardless, but a scan can't progress until the axes
        // are homed: before READY the firmware leaves coils disabled and clamps
        // MOVE targets to a coarse bench guard, so no waypoint is ever reached and
        // the move/settle cycle stalls silently. Refuse with a clear message
        // instead. (Single-axis builds report no P: segment, so skip pitch.)
        MotorTelemetry t = motor->telemetry();
        if (!t.yaw.ready() || (t.pitch_present && !t.pitch.ready())) {
            LOG_WARN << "Capture not started: gimbal not homed (run init/home first)";
            return;
        }
        camera->start();
        scheduler->setCaptureActive(true);
        LOG_INFO << "Capture started";
    }
    void stopCapture() {
        camera->stop();
        scheduler->setCaptureActive(false);
        LOG_INFO << "Capture stopped";
    }

    // `trace off|none`, `trace all`, or `trace <cat> [on|off]` — toggle the
    // verbatim wire-trace categories (serial/mqtt/camera/control).
    void handleTrace(const Command& c) {
        if (c.device.empty() || c.device == "off" || c.device == "none") {
            Logger::setCategories(0);
        } else if (c.device == "all") {
            Logger::setCategories(static_cast<unsigned>(LogCat::All));
        } else {
            bool ok = true;
            LogCat cat = Logger::catFromString(c.device, &ok);
            if (!ok) {
                LOG_WARN << "unknown trace category: " << c.device;
                return;
            }
            bool on = (c.option != "off");  // "trace serial" / "trace serial on" => enable
            if (on) Logger::enableCategory(cat);
            else    Logger::disableCategory(cat);
        }
        LOG_INFO << "trace categories: " << traceNames(Logger::categories());
    }

    // `goto <yaw_deg> <pitch_deg>` — aim the gimbal at an absolute heading and
    // elevation in degrees. Converts to encoder counts via the operator-calibrated
    // Geometry maps (which soft-clamp to the travel limits) and issues a two-axis
    // MOVE so both axes start together.
    // Parse "<a>,<b>" or "<a> <b>" (tokens from `from` onward) into two numbers.
    static bool parsePair(const std::vector<std::string>& tok, size_t from,
                          double& a, double& b) {
        std::string s;
        for (size_t i = from; i < tok.size(); ++i) s += tok[i] + " ";
        for (char& ch : s) if (ch == ',') ch = ' ';
        std::istringstream iss(s);
        return static_cast<bool>(iss >> a >> b);
    }

    // Homed physical travel (counts) for an axis: the endstop-to-endstop span from
    // the last firmware dump. Returns 0 if no dump has been captured yet (caller
    // should request one). Deliberately does NOT fall back to the configured degree
    // range × counts_per_deg — that conflates calibration with physical travel and,
    // when min/max are unset, yields an absurd span.
    long homedTravelCounts(char axis) {
        DumpData d = parseDump(motor->lastDump());
        if (d.valid)
            for (const auto& ax : d.axes)
                if (ax.axis == axis) return std::labs(ax.lim_pos - ax.lim_neg);
        return 0;
    }

    // `gimbal <subcommand>` — unified, lowercase motor control. `move` is degrees
    // (default), `steps` is raw encoder counts; the rest map to firmware verbs.
    void handleGimbal(const std::string& line) {
        std::istringstream iss(line);
        std::vector<std::string> tok;
        std::string t;
        while (iss >> t) tok.push_back(t);  // tok[0] == "gimbal"
        if (tok.size() < 2) {
            LOG_WARN << "usage: gimbal <move|steps|nudge|home|stop|reset|enable|disable|"
                        "speed|setpos|status|dump|calib|raw>  (self-test: 'test')";
            return;
        }
        std::string sub = tok[1];
        for (char& ch : sub) ch = static_cast<char>(std::tolower((unsigned char)ch));

        if (sub == "move") {
            double yaw_deg = 0, pitch_deg = 0;
            if (!parsePair(tok, 2, yaw_deg, pitch_deg)) {
                LOG_WARN << "usage: gimbal move <yaw_deg>,<pitch_deg>";
                return;
            }
            long yc = cfg.geometry.yaw.toCounts(yaw_deg);
            long pc = cfg.geometry.pitch.toCounts(pitch_deg);
            LOG_INFO << "gimbal move yaw=" << yaw_deg << " pitch=" << pitch_deg
                     << " deg -> MOVE " << yc << "," << pc;
            motor->sendCommand("MOVE " + std::to_string(yc) + "," + std::to_string(pc));
        } else if (sub == "steps") {
            double yc = 0, pc = 0;
            if (!parsePair(tok, 2, yc, pc)) {
                LOG_WARN << "usage: gimbal steps <yaw_counts>,<pitch_counts>";
                return;
            }
            motor->sendCommand("MOVE " + std::to_string((long)yc) + "," + std::to_string((long)pc));
        } else if (sub == "nudge") {
            if (tok.size() < 4) { LOG_WARN << "usage: gimbal nudge <yaw|pitch> <+/-pct>"; return; }
            char axis = (tok[2][0] == 'p' || tok[2][0] == 'P') ? 'P' : 'Y';
            double pct = 0;
            try { pct = std::stod(tok[3]); } catch (...) { LOG_WARN << "gimbal nudge: bad percent"; return; }
            // Nudge is a fraction of the *homed* physical travel (endstop-to-endstop
            // from the firmware dump), so it is independent of calibration and never
            // a fraction of the configured degree clamps. If no dump is available
            // yet, request one and bail rather than guessing.
            long range = homedTravelCounts(axis);
            if (range <= 0) {
                LOG_WARN << "gimbal nudge: homed travel unknown; home or 'gimbal dump' first";
                motor->sendCommand("DUMP");
                return;
            }
            MotorTelemetry tel = motor->telemetry();
            long cur = (axis == 'Y') ? tel.yaw.xenc : tel.pitch.xenc;
            long target = cur + static_cast<long>(pct / 100.0 * range);
            LOG_INFO << "gimbal nudge " << axis << " " << pct << "% -> MOVE " << axis << " " << target;
            motor->sendCommand(std::string("MOVE ") + axis + " " + std::to_string(target));
        } else if (sub == "calib") {
            startCalibration();
        } else if (sub == "dump") {
            LOG_INFO << "requesting firmware dump...";
            motor->sendCommand("DUMP");
        } else if (sub == "raw") {
            // Low-level escape hatch: send the text inside the quotation marks to
            // the serial port verbatim (the transport appends the newline). This
            // exposes any firmware verb directly, including ones with no wrapper.
            std::string raw;
            auto q1 = line.find('"');
            auto q2 = line.rfind('"');
            if (q1 != std::string::npos && q2 != std::string::npos && q2 > q1) {
                raw = line.substr(q1 + 1, q2 - q1 - 1);  // exact text between quotes
            } else {
                for (size_t i = 2; i < tok.size(); ++i)  // unquoted: join remaining tokens
                    raw += (raw.empty() ? "" : " ") + tok[i];
            }
            if (raw.empty()) {
                LOG_WARN << "usage: gimbal raw \"<verbatim firmware command>\"";
                return;
            }
            LOG_INFO << "gimbal raw -> " << raw;
            motor->sendCommand(raw);
        } else if (sub == "home" && tok.size() <= 2) {
            // Full re-home: enable + HOME + wait for READY + re-anchor the yaw zero
            // (same path as startup --init), so the homing key behaves like a boot
            // home rather than a fire-and-forget HOME that skips the re-anchor.
            runInitSequence();
        } else if (sub == "home" || sub == "stop" || sub == "reset" || sub == "enable" ||
                   sub == "disable" || sub == "speed" || sub == "setpos" || sub == "status") {
            // Passthrough to the (case-insensitive) firmware verb + args.
            std::string fw = sub;
            for (char& ch : fw) ch = static_cast<char>(std::toupper((unsigned char)ch));
            for (size_t i = 2; i < tok.size(); ++i) fw += " " + tok[i];
            motor->sendCommand(fw);
        } else {
            LOG_WARN << "unknown gimbal subcommand: " << sub;
        }
    }

    void startCalibration() {
        if (!imu) { LOG_WARN << "gimbal calib requires the IMU (set [Features] enable_imu)"; return; }
        if (calib && calib->running()) { LOG_WARN << "calibration already running (gimbal stop to cancel)"; return; }
        stopCapture();  // free the serial link + don't fight the routine's moves
        calib = std::make_unique<CalibrationRoutine>(*motor, *imu, cfg.geometry);
        calib->start();
    }

    // Persist the live (just-calibrated) [Motor] geometry back into config.ini.
    void saveCalibration() {
        if (!calib_save_pending_) return;
        calib_save_pending_ = false;
        if (saveMotorCalibration(opts.config_path, cfg.geometry))
            LOG_INFO << "calibration saved as the new default in " << opts.config_path;
        else
            LOG_WARN << "could not write calibration to " << opts.config_path;
    }

    void cancelCalibration() {
        if (calib && calib->running()) {
            LOG_INFO << "cancelling calibration";
            calib->cancel();
            motor->sendCommand("STOP ALL");
        }
    }

    // ---- Procedure lock-out (test / calibration / homing are mutually exclusive) ----
    enum class Procedure { None, Homing, Calibration, Test };
    Procedure activeProcedure() const {
        if (tester && tester->running()) return Procedure::Test;
        if (calib && calib->running())   return Procedure::Calibration;
        if (homing_active_.load())       return Procedure::Homing;
        return Procedure::None;
    }
    bool procedureBusy() const { return activeProcedure() != Procedure::None; }
    const char* procedureName() const {
        switch (activeProcedure()) {
            case Procedure::Test:        return "test";
            case Procedure::Calibration: return "calibration";
            case Procedure::Homing:      return "homing";
            default:                     return "none";
        }
    }

    void cancelActiveProcedure() {
        switch (activeProcedure()) {
            case Procedure::Test:
                LOG_INFO << "cancelling test";
                tester->cancel();
                motor->sendCommand("STOP ALL");
                break;
            case Procedure::Calibration:
                cancelCalibration();
                break;
            case Procedure::Homing:
                LOG_INFO << "cancelling homing";
                cancel_procedure_ = true;
                motor->sendCommand("STOP ALL");
                break;
            case Procedure::None:
                LOG_INFO << "nothing to cancel";
                break;
        }
    }

    // Pop the command queue and drop any interfering command (homing runs on the
    // control thread, so handleCommand() is not reached during it). Used inside
    // runInitSequence()'s wait loops so queued moves are *ignored*, not deferred.
    void drainAndDiscardCommands() {
        std::queue<std::string> local;
        {
            std::lock_guard<std::mutex> lock(cmd_mutex);
            std::swap(local, cmd_queue);
        }
        while (!local.empty()) {
            const std::string& line = local.front();
            Command c = parseCommand(line);
            if (c.verb == "cancel" || c.verb == "stop")
                cancel_procedure_ = true;
            else if (!c.empty())
                LOG_WARN << "ignored '" << c.verb << "': homing in progress (Esc to cancel)";
            local.pop();
        }
    }

    // ---- `test` command ----
    static std::string lowerStr(std::string s) {
        for (char& ch : s) ch = static_cast<char>(std::tolower((unsigned char)ch));
        return s;
    }

    void handleTest(const std::string& line) {
        std::istringstream iss(line);
        std::vector<std::string> tok;
        std::string t;
        while (iss >> t) tok.push_back(t);  // tok[0] == "test"

        if (tok.size() >= 2) {
            std::string sub = lowerStr(tok[1]);
            if (sub == "baseline") { promoteBaseline(); return; }
            if (sub == "list")     { listTestProfiles(); return; }
        }

        // Split [subsystem] [test] [profile]: a token naming a configured profile
        // is the profile; the remaining (ordered) tokens are subsystem then test.
        std::string subsystem, leaf, profileName;
        for (size_t i = 1; i < tok.size(); ++i) {
            std::string w = lowerStr(tok[i]);
            if (profileName.empty() && cfg.test.profiles.count(w)) { profileName = w; continue; }
            if (subsystem.empty())      subsystem = w;
            else if (leaf.empty())      leaf = w;
        }
        if (profileName.empty()) profileName = cfg.test.default_profile;

        uint32_t mask = 0;
        std::string err;
        if (!resolveTestSelection(subsystem, leaf, mask, err)) {
            LOG_WARN << "test: " << err;
            LOG_INFO << "usage: test [gimbal|imu|host [<leaf>]] [<profile>]   (also: test list, test baseline)";
            return;
        }
        startTest(mask, profileName);
    }

    void startTest(uint32_t mask, const std::string& profileName) {
        if (procedureBusy()) {
            LOG_WARN << "test: " << procedureName() << " already in progress (Esc to cancel)";
            return;
        }
        // IMU leaves need an IMU; drop them (with a warning) if absent.
        if ((mask & T_NEEDS_IMU) && !imu) {
            LOG_WARN << "test: IMU tests skipped (set [Features] enable_imu)";
            mask &= ~T_NEEDS_IMU;
        }
        // Motor leaves need a homed gimbal.
        if (mask & T_NEEDS_MOTOR) {
            MotorTelemetry tel = motor->telemetry();
            if (!tel.yaw.ready() && !(tel.pitch_present && tel.pitch.ready())) {
                LOG_WARN << "test: gimbal not READY (home first)";
                return;
            }
        }
        if (mask == 0) { LOG_WARN << "test: nothing to run"; return; }

        TestProfile profile;
        if (const TestProfile* p = cfg.test.find(profileName)) profile = *p;
        else profile.name = profileName;  // unknown name => built-in defaults
        test_drift_warn_ = profile.get("drift_warn_pct", 15.0);
        test_drift_gate_ = profile.getBool("drift_gates_pass", false);

        stopCapture();  // free the serial link; don't fight the routine's moves
        LOG_INFO << "starting hardware test (profile '" << profile.name << "')";
        tester = std::make_unique<TestRunner>(*motor, imu.get(), cfg.geometry, mask, profile,
                                              cfg.paths.output_dir);
        tester->start();
    }

    void listTestProfiles() {
        LOG_INFO << "test profiles (default: " << cfg.test.default_profile << "):";
        if (cfg.test.profiles.empty()) LOG_INFO << "  (none configured; built-in defaults used)";
        for (const auto& [name, p] : cfg.test.profiles)
            LOG_INFO << "  " << name << "  (" << p.params.size() << " params)";
    }

    std::string baselinePath() const {
        return cfg.test.baseline_file.empty()
                   ? (paths::defaultLogDir() + "/test_baseline.txt")
                   : cfg.test.baseline_file;
    }

    void promoteBaseline() {
        if (last_test_report_path.empty()) {
            LOG_WARN << "test baseline: no test report from this session to promote";
            return;
        }
        std::error_code ec;
        std::filesystem::copy_file(last_test_report_path, baselinePath(),
                                   std::filesystem::copy_options::overwrite_existing, ec);
        if (ec) LOG_WARN << "test baseline: copy failed: " << ec.message();
        else    LOG_INFO << "test baseline set from " << last_test_report_path << " -> " << baselinePath();
    }

    // Read+parse a report file; returns valid()==false-ish empty report on failure.
    static bool loadReport(const std::string& path, TestReport& out) {
        std::ifstream f(path);
        if (!f) return false;
        std::ostringstream ss;
        ss << f.rdbuf();
        out = parseTestReport(ss.str());
        return !out.sections.empty();
    }

    // Most recent prior "test_*.log" in the log dir (excluding `exclude`).
    std::string latestPriorTestReport(const std::string& exclude) const {
        namespace fs = std::filesystem;
        std::string best;
        std::error_code ec;
        const std::string dir = paths::defaultLogDir();
        if (!fs::exists(dir, ec)) return best;
        for (auto& e : fs::directory_iterator(dir, ec)) {
            const std::string name = e.path().filename().string();
            if (name.rfind("test_", 0) != 0 || e.path().extension() != ".log") continue;
            if (e.path().string() == exclude) continue;
            if (best.empty() || name > fs::path(best).filename().string())
                best = e.path().string();
        }
        return best;
    }

    // Pick up results produced by background work (calibration thread, DIAG
    // capture) — runs on the control thread each tick so all geometry/state
    // mutation stays single-threaded.
    void pollBackgroundResults() {
        if (calib) {
            if (auto g = calib->takeResult()) {
                cfg.geometry = *g;
                if (scheduler) scheduler->setGeometry(cfg.geometry);  // also fix scan targeting
                LOG_INFO << "calibration applied to live geometry";
                // Capture the structured report for the activity strip + gimbal view.
                CalibReport rep = calib->report();
                CalibResultView v;
                v.has = rep.valid;
                v.ts_ms = rep.ts_ms;
                last_calib_summary.clear();
                for (const auto& ax : rep.axes) {
                    CalibAxisView* dst = (ax.axis == 'P') ? &v.pitch : &v.yaw;
                    if (ax.axis == 'P') v.pitch_present = true;
                    dst->ok = ax.ok;
                    dst->counts_per_deg = ax.counts_per_deg;
                    dst->zero_count = ax.zero_count;
                    dst->r2 = ax.r2;
                    dst->n = ax.n;
                    char b[96];
                    std::snprintf(b, sizeof(b), "%s  cpd=%.3f  zero=%ld  R2=%.4f (n=%d)%s",
                                  ax.axis == 'P' ? "PITCH" : "YAW", ax.counts_per_deg,
                                  ax.zero_count, ax.r2, ax.n, ax.ok ? "" : "  FIT FAILED");
                    last_calib_summary.emplace_back(b);
                }
                last_calib_view = v;
                last_calib_ts   = nowEpochMs();
                // Offer to persist it as the new default (answered via the activity strip).
                if (rep.valid && !opts.config_path.empty()) calib_save_pending_ = true;
            }
        }
        if (tester) {
            if (auto rep = tester->takeReport()) {
                TestReport r = std::move(*rep);
                // Compare against the pinned baseline and the most recent prior run.
                TestReport baseline, prev;
                bool have_baseline = loadReport(baselinePath(), baseline);
                bool have_prev = loadReport(latestPriorTestReport(""), prev);
                applyComparison(r, have_baseline ? &baseline : nullptr,
                                have_prev ? &prev : nullptr, test_drift_warn_, test_drift_gate_);

                std::string text = formatTestReport(r);
                std::string path = paths::writeLogFile(paths::timestampedLogName("test"), text);
                if (!path.empty()) {
                    last_test_report_path = path;
                    LOG_INFO << "test report written: " << path;
                }
                // Surface a concise per-section summary in the log + activity strip.
                last_test_summary.clear();
                for (const auto& s : r.sections) {
                    if (!s.ran) continue;
                    std::string l = s.id + ": " + (s.pass ? "PASS" : "FAIL");
                    last_test_summary.push_back(l);
                    LOG_INFO << "test " << l;
                }
                LOG_INFO << "test overall: " << (r.all_pass ? "PASS" : "FAIL")
                         << "  (profile " << r.profile << ")";
                last_test_pass = r.all_pass;
                last_test_ts   = nowEpochMs();
                last_test_view = TestResultView{};
                last_test_view.has = true;
                last_test_view.ts_ms = last_test_ts;
                last_test_view.pass = r.all_pass;
                last_test_view.profile = r.profile;
                last_test_view.summary = last_test_summary;
            }
        }
        unsigned seq = motor->diagSeq();
        if (seq != last_diag_seq) {
            last_diag_seq = seq;
            diag_running_ = false;
            DiagResult dr = parseDiag(motor->lastDiag());
            std::ostringstream summary;
            for (const auto& l : formatDiag(dr)) { LOG_INFO << l; summary << l << "\n"; }
            // Concise per-axis lines for the activity strip + the per-axis worst
            // tracking error for the gimbal view. Full detail is logged above.
            last_diag_summary.clear();
            last_diag_view = DiagResultView{};
            last_diag_view.has = dr.valid;
            for (const auto& ax : dr.axes) {
                DiagAxisView dv;
                dv.axis = ax.axis;
                dv.has  = !ax.tests.empty();
                dv.pass = ax.pass;
                dv.err_peak = dv.err_rms = dv.err_still = -1;  // -1 stays if no encoder
                for (const auto& tst : ax.tests) {  // worst (max) across the tests
                    if (tst.err_peak < 0) continue;  // no-encoder test: skip
                    dv.err_peak  = std::max(dv.err_peak, tst.err_peak);
                    dv.err_rms   = std::max(dv.err_rms, tst.err_rms);
                    dv.err_still = std::max(dv.err_still, tst.err_still);
                }
                last_diag_view.axes.push_back(dv);
                std::string line = std::string(1, ax.axis) + ": " +
                                   (ax.pass ? "PASS" : "FAIL");
                if (dv.has && dv.err_peak >= 0)  // -1 == no encoder
                    line += "  peak " + std::to_string(dv.err_peak) +
                            " still " + std::to_string(dv.err_still);
                line += "  (" + std::to_string(ax.tests.size()) + " tests)";
                last_diag_summary.push_back(line);
            }
            last_diag_pass = dr.allPass();
            last_diag_ts   = nowEpochMs();
            last_diag_view.ts_ms = last_diag_ts;
            std::string path = paths::writeLogFile(
                paths::timestampedLogName("diag"),
                motor->lastDiag() + "\n--- parsed ---\n" + summary.str());
            if (!path.empty()) LOG_INFO << "diagnostics log written: " << path;
        }
        // Safety: clear a stuck diag flag if the firmware never replied.
        if (diag_running_ &&
            std::chrono::steady_clock::now() - diag_started_ > std::chrono::seconds(30))
            diag_running_ = false;
    }

    // Commands that would disturb a running procedure (motion, capture, a second
    // long op, or a DUMP over the same serial link). Ignored while busy.
    static bool interferingVerb(const std::string& verb) {
        return verb == "gimbal" || verb == "start" || verb == "calib" ||
               verb == "test" || verb == "refresh";
    }

    void handleCommand(const std::string& line) {
        Command c = parseCommand(line);
        if (c.empty()) return;
        LOG_TRACE_CAT(LogCat::Control) << "cmd " << line;

        // Lock-out: while a test/calibration/homing runs, ignore interfering
        // commands (Esc, or `stop`/`cancel`, cancels the procedure instead).
        if (procedureBusy() && interferingVerb(c.verb)) {
            LOG_WARN << "ignored '" << c.verb << "': " << procedureName()
                     << " in progress (Esc to cancel)";
            return;
        }

        if (c.verb == "help") {
            // c.device holds the optional topic (first token after "help").
            for (const auto& l : renderHelp(c.device)) LOG_INFO << l;
        } else if (c.verb == "test") {
            handleTest(line);
        } else if (c.verb == "cancel") {
            cancelActiveProcedure();
        } else if (c.verb == "gimbal") {
            handleGimbal(line);
        } else if (c.verb == "calib") {
            // Answer to the "save calibration?" prompt (activity-strip y/n keys).
            if (c.device == "save") saveCalibration();
            else if (c.device == "discard") {
                calib_save_pending_ = false;
                LOG_INFO << "calibration kept for this session only (not saved to config)";
            }
        } else if (c.verb == "exit") {
            running = false;
        } else if (c.verb == "start") {
            startCapture();
        } else if (c.verb == "stop") {
            // `stop`/`x` cancels any running procedure, else stops capture.
            if (procedureBusy()) cancelActiveProcedure();
            else stopCapture();
        } else if (c.verb == "debug") {
            bool on = Logger::level() != LogLevel::Debug;
            Logger::setLevel(on ? LogLevel::Debug : LogLevel::Info);
            LOG_INFO << "debug logging " << (on ? "on" : "off");
        } else if (c.verb == "refresh") {
            // Re-read live device state surfaced in the expanded views: the IMU
            // configuration (e.g. after the XKF profile was changed externally)
            // and the firmware register dump shown in the gimbal 'g' view.
            LOG_INFO << "refresh: re-reading IMU configuration + firmware dump";
            if (imu) {
                imu->refreshConfig();
                imu_config_done_ = false;  // force buildSnapshot to re-read config()
            }
            motor->sendCommand("DUMP");
        } else if (c.verb == "trace") {
            handleTrace(c);
        } else if (c.verb == "set") {
            if (c.device == "camera") {
                // "set camera mode night" arrives as option="mode night": the parser
                // joins non-numeric trailing tokens into `option`.
                if (c.option.rfind("mode ", 0) == 0) applyMode(c.option.substr(5));
                else if (c.option == "mode") LOG_WARN << "usage: set camera mode <name>";
                else if (c.option == "jxlq" && c.has_value) pipeline->setDistance(c.value);
                else if (c.option == "jxle" && c.has_value) pipeline->setEffort(static_cast<int>(c.value));
                else if (c.option == "display") pipeline->setDisplay(c.value != 0.0);
                else LOG_WARN << "unknown 'set camera' option: " << c.option;
            } else if (c.device == "fps" && c.has_value) {
                scheduler->setImageRate(c.value);
                LOG_INFO << "capture rate set to " << c.value << " img/s";
            } else {
                LOG_WARN << "unknown 'set' target: " << c.device;
            }
        } else {
            LOG_WARN << "unknown command: " << c.verb;
        }
    }

    void drainCommands() {
        std::queue<std::string> local;
        {
            std::lock_guard<std::mutex> lock(cmd_mutex);
            std::swap(local, cmd_queue);
        }
        while (!local.empty()) {
            handleCommand(local.front());
            local.pop();
        }
    }

    int run() {
        start_time = std::chrono::steady_clock::now();

        // Log level: config first, CLI overrides.
        if (!cfg.logging.level.empty() && !Logger::setLevelFromString(cfg.logging.level))
            LOG_WARN << "unknown Logging.level '" << cfg.logging.level << "', keeping default";
        if (!opts.log_level.empty() && !Logger::setLevelFromString(opts.log_level))
            LOG_WARN << "unknown log level '" << opts.log_level << "', keeping default";

        // Wire-trace categories: config first, CLI overrides (replaces, not merges).
        if (!cfg.logging.trace.empty()) {
            bool ok = true;
            unsigned m = Logger::parseCategories(cfg.logging.trace, &ok);
            if (!ok) LOG_WARN << "unknown trace category in Logging.trace '" << cfg.logging.trace << "'";
            Logger::setCategories(m);
        }
        if (!opts.trace_categories.empty()) {
            bool ok = true;
            unsigned m = Logger::parseCategories(opts.trace_categories, &ok);
            if (!ok) LOG_WARN << "unknown trace category in '" << opts.trace_categories << "'";
            Logger::setCategories(m);
        }
        if (Logger::categories())
            LOG_INFO << "wire trace enabled: " << traceNames(Logger::categories());

        loadModes();  // before makeCamera(): the mode is applied at start()

        channel = makeChannel();
        motor   = makeMotor();
        camera  = makeCamera();
        imu     = makeImu();
        env     = makeEnv();

        if (!channel->connect())
            LOG_WARN << "Control channel not connected; continuing in degraded mode";

        // Verify the capture output dir is writable up front; if not (e.g. a
        // misconfigured absolute path), fall back to the per-user default so
        // captures land on disk instead of failing once per frame. Resolved once
        // here, then used everywhere via cfg.paths.output_dir.
        if (!outputDirWritable(cfg.paths.output_dir)) {
            const std::string fb = paths::defaultOutputDir();
            LOG_ERROR << "capture output_dir '" << cfg.paths.output_dir
                      << "' is not writable; falling back to '" << fb << "'";
            cfg.paths.output_dir = fb;
            if (!outputDirWritable(cfg.paths.output_dir))
                LOG_ERROR << "fallback output_dir '" << fb
                          << "' is also not writable; captures will fail to save";
        }
        LOG_INFO << "capture output dir: " << cfg.paths.output_dir;

        ImagePipeline::Params pp;
        pp.output_dir = cfg.paths.output_dir;
        pp.labels     = cfg.camera.labels;
        pp.tower      = cfg.general.tower_name;
        pp.demo       = opts.demo;
        pp.jxl_distance = cfg.camera.jxl_distance;
        pp.jxl_effort   = cfg.camera.jxl_effort;
        pp.rotation_deg = cfg.camera.rotation_deg;
        // Orientation supplier: convert the per-axis encoder counts to degrees.
        pipeline = std::make_unique<ImagePipeline>(
            *channel,
            [this] {
                MotorTelemetry t = motor->telemetry();
                return Orientation{static_cast<float>(cfg.geometry.yaw.toDeg(t.yaw.xenc)),
                                   static_cast<float>(cfg.geometry.pitch.toDeg(t.pitch.xenc))};
            },
            pp);

        ImagePipeline* pipe_ptr = pipeline.get();
        camera->setFrameCallback([pipe_ptr](const Frame& f) { pipe_ptr->submit(f); });

        try {
            grid = ScanGrid::fromConfig(cfg.scan);
        } catch (const std::exception& e) {
            scan_load_error_ = e.what();
            LOG_WARN << "scan grid load failed (" << e.what() << "); auto-sweep disabled";
        }
        LOG_INFO << "scan grid: " << grid.size() << " waypoints";
        scheduler = std::make_unique<CaptureScheduler>(*motor, *camera, *channel, cfg.image_rate(),
                                                       cfg.geometry, grid);
        {
            const CameraMode& m = camera_modes.at(camera_mode);
            scheduler->setSettleWait(m.settle_wait_ms, m.frame_timeout_ms);
        }

        motor->start();
        if (imu) imu->start();
        if (env) env->start();
        camera->open();
        pipeline->start();
        channel->publishStatus(0);

        // Seed an initial snapshot so the UI's first frame is populated, then
        // start the interface (headless console or TUI) on its own thread. The
        // UI is a pure observer: it pulls snapshots and pushes command strings
        // into the same queue the console always used.
        //
        // The UI is brought up BEFORE the init/home sequence so the dashboard is
        // visible during homing (which can take many seconds) and so the serial
        // wire traces render in the TUI's log pane instead of scrolling raw —
        // makeUi()/start() installs the TUI log sink, so anything logged after
        // this point is captured by it.
        publishSnapshot();
        ui = makeUi();
        ui->start([this] { std::lock_guard<std::mutex> lk(snapshot_mutex); return latest_snapshot; },
                  [this](const std::string& line) {
                      std::lock_guard<std::mutex> lk(cmd_mutex);
                      cmd_queue.push(line);
                  });

        if (opts.init) {
            runInitSequence();  // homes, then re-anchors the yaw zero
        } else if (cfg.yaw_home_zero != YawHomeZero::Off) {
            // No homing this launch: the firmware restores its homed limits from
            // EEPROM to READY on boot, so re-derive the same yaw zero from them.
            // This makes the homing-anchored zero persist across software restarts
            // without re-homing. Self-guards (no-op + note) if not yet homed.
            applyYawHomeZero();
        }
        if (opts.start) startCapture();

        // Clean up on Ctrl-C / kill / systemd stop, not just on "exit"/Ctrl-D - so the
        // camera is always stopped and closed (an unclean exit wedges it for next time).
        std::signal(SIGINT, handleShutdownSignal);
        std::signal(SIGTERM, handleShutdownSignal);

        LOG_INFO << "Entering control loop (type 'exit' to quit, or Ctrl-C)";
        while (running && !g_shutdown_requested.load()) {
            drainCommands();
            pollBackgroundResults();  // apply calibration result / emit DIAG summary+log
            scheduler->tick();
            checkTrackingError();     // warn on live encoder-error excursions
            publishSnapshot();
            std::this_thread::sleep_for(std::chrono::milliseconds(10));
        }

        LOG_INFO << "Shutting down";
        if (tester) tester->cancel();  // stop any in-flight self-test before teardown
        if (calib) calib->cancel();  // stop any in-flight calibration before teardown
        if (ui) ui->stop();
        pipeline->stop();
        camera->stop();
        camera->close();
        if (imu) imu->stop();
        if (env) env->stop();
        motor->stop();
        channel->disconnect();
        return 0;
    }
};

Application::Application(AppConfig config, RuntimeOptions options)
    : impl_(std::make_unique<Impl>(std::move(config), std::move(options))) {}

Application::~Application() = default;

int Application::run() { return impl_->run(); }

}  // namespace fgc