// lesavka-server - gadget cycle guarded by env
// server/src/main.rs
#[allow(clippy::useless_attribute)]
#[forbid(unsafe_code)]
use anyhow::Context;
use futures_util::{Stream, StreamExt};
use std::collections::HashMap;
use std::collections::HashSet;
use std::os::unix::fs::FileTypeExt;
use std::process::Command;
use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
use std::{backtrace::Backtrace, panic, pin::Pin, sync::Arc, time::Duration};
use tokio::sync::{Mutex, broadcast};
use tokio_stream::wrappers::ReceiverStream;
use tonic::transport::Server;
use tonic::{Request, Response, Status};
use tonic_reflection::server::Builder as ReflBuilder;
use tracing::{debug, error, info, warn};

use lesavka_common::lesavka::{
    AudioPacket, CapturePowerCommand, CapturePowerState, Empty, KeyboardReport, MonitorRequest,
    MouseReport, PasteReply, PasteRequest, ResetUsbReply, SetCapturePowerRequest, VideoPacket,
    relay_server::{Relay, RelayServer},
};

use lesavka_server::{
    camera, camera_runtime::CameraRuntime, capture_power::CapturePowerManager, gadget::UsbGadget,
    handshake::HandshakeSvc, paste, runtime_support, runtime_support::init_tracing, uvc_runtime,
    video,
};

/*──────────────── constants ────────────────*/
const PKG_NAME: &str = env!("CARGO_PKG_NAME");

type VideoStream = Pin<Box<dyn Stream<Item = Result<VideoPacket, Status>> + Send>>;
type AudioStream = Pin<Box<dyn Stream<Item = Result<AudioPacket, Status>> + Send>>;

fn hid_endpoint(index: u8) -> String {
    std::env::var("LESAVKA_HID_DIR")
        .map(|dir| format!("{dir}/hidg{index}"))
        .unwrap_or_else(|_| format!("/dev/hidg{index}"))
}

fn live_keyboard_report_delay() -> Duration {
    std::env::var("LESAVKA_LIVE_KEYBOARD_REPORT_DELAY_MS")
        .ok()
        .and_then(|value| value.parse::<u64>().ok())
        .map(Duration::from_millis)
        .unwrap_or_else(|| Duration::from_millis(8))
}

/*──────────────── Handler ───────────────────*/
struct Handler {
    kb: Arc<Mutex<Option<tokio::fs::File>>>,
    ms: Arc<Mutex<Option<tokio::fs::File>>>,
    gadget: UsbGadget,
    did_cycle: Arc<AtomicBool>,
    camera_rt: Arc<CameraRuntime>,
    capture_power: CapturePowerManager,
    eye_hubs: Arc<Mutex<HashMap<EyeHubKey, Arc<EyeHub>>>>,
}

#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
struct EyeHubKey {
    source_id: u32,
    requested_width: u32,
    requested_height: u32,
    requested_fps: u32,
}

struct EyeHub {
    tx: broadcast::Sender<VideoPacket>,
    running: Arc<AtomicBool>,
    subscribers: Arc<AtomicUsize>,
    abort: tokio::task::AbortHandle,
}

impl Handler {
    async fn new(gadget: UsbGadget) -> anyhow::Result<Self> {
        #[cfg(not(coverage))]
        if runtime_support::allow_gadget_cycle() {
            info!("🛠️  Initial USB recovery…");
            match UsbGadget::current_controller_state() {
                Ok((ctrl, state)) if !UsbGadget::host_enumerated_state(&state) => {
                    warn!("⚠️ UDC {ctrl} is {state}; forcing gadget recovery before opening HID");
                    if let Err(error) = gadget.recover_enumeration() {
                        warn!("⚠️ initial USB recovery did not enumerate the host: {error:#}");
                    }
                }
                Ok(_) => {
                    let _ = gadget.cycle(); // ignore failure - may boot without host
                }
                Err(error) => {
                    warn!("⚠️ UDC state unavailable during startup: {error:#}");
                    let _ = gadget.cycle(); // preserve the old best-effort startup path
                }
            }
        }
        #[cfg(not(coverage))]
        {
            if !runtime_support::allow_gadget_cycle() {
                info!(
                    "🔒 gadget cycle disabled at startup (set LESAVKA_ALLOW_GADGET_CYCLE=1 to enable)"
                );
            }
            info!("🛠️  opening HID endpoints …");
        }
        let kb_path = hid_endpoint(0);
        let ms_path = hid_endpoint(1);
        let kb = runtime_support::open_hid_if_ready(&kb_path).await?;
        let ms = runtime_support::open_hid_if_ready(&ms_path).await?;
        #[cfg(not(coverage))]
        if kb.is_some() && ms.is_some() {
            info!("✅ HID endpoints ready");
        } else {
            warn!("⌛ HID endpoints are not ready; relay will keep running and open them lazily");
        }

        Ok(Self {
            kb: Arc::new(Mutex::new(kb)),
            ms: Arc::new(Mutex::new(ms)),
            gadget,
            did_cycle: Arc::new(AtomicBool::new(false)),
            camera_rt: Arc::new(CameraRuntime::new()),
            capture_power: CapturePowerManager::new(),
            eye_hubs: Arc::new(Mutex::new(HashMap::new())),
        })
    }

    async fn reopen_hid(&self) -> anyhow::Result<()> {
        let kb_new = runtime_support::open_hid_if_ready(&hid_endpoint(0)).await?;
        let ms_new = runtime_support::open_hid_if_ready(&hid_endpoint(1)).await?;
        *self.kb.lock().await = kb_new;
        *self.ms.lock().await = ms_new;
        Ok(())
    }

    fn detected_capture_devices_from_symlinks() -> u32 {
        ["/dev/lesavka_l_eye", "/dev/lesavka_r_eye"]
            .into_iter()
            .filter(|path| {
                std::fs::metadata(path)
                    .ok()
                    .is_some_and(|metadata| metadata.file_type().is_char_device())
            })
            .count() as u32
    }

    fn detected_capture_devices_from_udev() -> u32 {
        let Ok(mut enumerator) = udev::Enumerator::new() else {
            return 0;
        };
        let _ = enumerator.match_subsystem("video4linux");
        let Ok(devices) = enumerator.scan_devices() else {
            return 0;
        };
        devices
            .filter(|device| {
                device
                    .attribute_value("index")
                    .and_then(|value| value.to_str())
                    == Some("0")
                    && device
                        .property_value("ID_VENDOR_ID")
                        .and_then(|value| value.to_str())
                        == Some("07ca")
                    && device
                        .property_value("ID_MODEL_ID")
                        .and_then(|value| value.to_str())
                        == Some("3311")
            })
            .count()
            .min(2) as u32
    }

    async fn active_eye_source_count(&self) -> u32 {
        self.eye_hubs
            .lock()
            .await
            .iter()
            .filter_map(|(key, hub)| hub.running.load(Ordering::Relaxed).then_some(key.source_id))
            .collect::<HashSet<_>>()
            .len()
            .min(2) as u32
    }

    async fn with_detected_capture_devices(
        &self,
        mut state: CapturePowerState,
    ) -> CapturePowerState {
        state.detected_devices = Self::detected_capture_devices_from_udev()
            .max(Self::detected_capture_devices_from_symlinks())
            .max(self.active_eye_source_count().await);
        state
    }

    async fn capture_video_reply(
        &self,
        req: MonitorRequest,
    ) -> Result<Response<VideoStream>, Status> {
        let id = req.id;
        if id > 1 {
            return Err(Status::invalid_argument("monitor id must be 0 or 1"));
        }
        let source_id = req.source_id.unwrap_or(id);
        if source_id > 1 {
            return Err(Status::invalid_argument("source id must be 0 or 1"));
        }
        let dev = match source_id {
            0 => "/dev/lesavka_l_eye",
            1 => "/dev/lesavka_r_eye",
            _ => return Err(Status::invalid_argument("source id must be 0 or 1")),
        };

        #[cfg(not(coverage))]
        {
            let rpc_id = runtime_support::next_stream_id();
            info!(
                rpc_id,
                id,
                source_id,
                max_bitrate = req.max_bitrate,
                requested_width = req.requested_width,
                requested_height = req.requested_height,
                requested_fps = req.requested_fps,
                "🎥 capture_video opened"
            );
            debug!(rpc_id, "🎥 streaming {dev}");
        }

        let hub = self
            .eye_hub(
                dev,
                EyeHubKey {
                    source_id,
                    requested_width: req.requested_width,
                    requested_height: req.requested_height,
                    requested_fps: req.requested_fps,
                },
                req.max_bitrate,
            )
            .await?;

        let mut hub_rx = hub.tx.subscribe();
        hub.subscribers.fetch_add(1, Ordering::AcqRel);
        let subscribers = Arc::clone(&hub.subscribers);
        let hub_for_task = Arc::clone(&hub);
        let (tx, rx) = tokio::sync::mpsc::channel(32);
        tokio::spawn(async move {
            loop {
                match hub_rx.recv().await {
                    Ok(mut pkt) => {
                        pkt.id = id;
                        if tx.send(Ok(pkt)).await.is_err() {
                            break;
                        }
                    }
                    Err(broadcast::error::RecvError::Lagged(_)) => continue,
                    Err(broadcast::error::RecvError::Closed) => break,
                }
            }
            if subscribers.fetch_sub(1, Ordering::AcqRel) == 1 {
                hub_for_task.shutdown();
            }
        });

        Ok(Response::new(Box::pin(ReceiverStream::new(rx))))
    }

    async fn eye_hub(
        &self,
        dev: &str,
        key: EyeHubKey,
        max_bitrate_kbit: u32,
    ) -> Result<Arc<EyeHub>, Status> {
        let stale_hubs = {
            let mut hubs = self.eye_hubs.lock().await;
            if let Some(hub) = hubs.get(&key)
                && hub.running.load(Ordering::Relaxed)
            {
                return Ok(Arc::clone(hub));
            }
            take_conflicting_eye_hubs(&mut hubs, key)
        };
        if !stale_hubs.is_empty() {
            info!(
                source_id = key.source_id,
                requested_width = key.requested_width,
                requested_height = key.requested_height,
                requested_fps = key.requested_fps,
                stale_hubs = stale_hubs.len(),
                "🎥 replacing stale/conflicting eye hubs before opening the source"
            );
        }
        for hub in stale_hubs {
            hub.shutdown();
        }

        let lease = self.capture_power.acquire().await;
        let stream = video::eye_ball_with_request(
            dev,
            key.source_id,
            max_bitrate_kbit,
            key.requested_width,
            key.requested_height,
            key.requested_fps,
        )
        .await
        .map_err(|e| Status::internal(format!("{e:#}")))?;

        let hub = EyeHub::spawn(stream, lease);
        let mut hubs = self.eye_hubs.lock().await;
        if let Some(existing) = hubs.get(&key)
            && existing.running.load(Ordering::Relaxed)
        {
            hub.shutdown();
            return Ok(Arc::clone(existing));
        }
        hubs.insert(key, Arc::clone(&hub));
        Ok(hub)
    }

    #[cfg(test)]
    async fn eye_hub_count(&self) -> usize {
        self.eye_hubs.lock().await.len()
    }

    async fn paste_text_reply(
        &self,
        req: Request<PasteRequest>,
    ) -> Result<Response<PasteReply>, Status> {
        let req = req.into_inner();
        let text = paste::decrypt(&req).map_err(|e| Status::unauthenticated(format!("{e}")))?;
        if let Err(e) = paste::type_text(&self.kb, &hid_endpoint(0), &text).await {
            return Ok(Response::new(PasteReply {
                ok: false,
                error: format!("{e}"),
            }));
        }
        Ok(Response::new(PasteReply {
            ok: true,
            error: String::new(),
        }))
    }

    async fn reset_usb_reply(&self) -> Result<Response<ResetUsbReply>, Status> {
        #[cfg(not(coverage))]
        info!("🔴 explicit ResetUsb() called");

        match self.gadget.recover_enumeration() {
            Ok(_) => {
                if let Err(e) = self.reopen_hid().await {
                    #[cfg(not(coverage))]
                    error!("💥 reopen HID failed: {e:#}");
                    return Err(Status::internal(e.to_string()));
                }
                if let Err(e) = restart_uvc_helper() {
                    #[cfg(not(coverage))]
                    error!("💥 restart UVC helper failed: {e:#}");
                    return Err(Status::internal(e.to_string()));
                }
                match UsbGadget::current_controller_state() {
                    Ok((ctrl, state)) if UsbGadget::host_enumerated_state(&state) => {
                        #[cfg(not(coverage))]
                        info!(
                            "✅ USB host enumerated gadget after recovery ctrl={ctrl} state={state}"
                        );
                    }
                    Ok((ctrl, state)) => {
                        let message = format!(
                            "USB gadget recovery ran, but UDC {ctrl} is still {state}; the controlled host has not enumerated the relay HID/audio/video gadget"
                        );
                        #[cfg(not(coverage))]
                        warn!("⚠️ {message}");
                        return Err(Status::failed_precondition(message));
                    }
                    Err(err) => {
                        let message = format!(
                            "USB gadget recovery ran, but the relay cannot read UDC state: {err:#}"
                        );
                        #[cfg(not(coverage))]
                        warn!("⚠️ {message}");
                        return Err(Status::failed_precondition(message));
                    }
                }
                Ok(Response::new(ResetUsbReply { ok: true }))
            }
            Err(e) => {
                #[cfg(not(coverage))]
                error!("💥 USB recovery failed: {e:#}");
                let message = format!("{e:#}");
                if message.contains("still not attached") || message.contains("not attached") {
                    Err(Status::failed_precondition(message))
                } else {
                    Err(Status::internal(message))
                }
            }
        }
    }

    async fn get_capture_power_reply(&self) -> Result<Response<CapturePowerState>, Status> {
        let state = self
            .capture_power
            .snapshot()
            .await
            .map_err(|e| Status::internal(format!("{e:#}")))?;
        Ok(Response::new(
            self.with_detected_capture_devices(state).await,
        ))
    }

    async fn set_capture_power_reply(
        &self,
        req: Request<SetCapturePowerRequest>,
    ) -> Result<Response<CapturePowerState>, Status> {
        let req = req.into_inner();
        let result = match CapturePowerCommand::try_from(req.command)
            .unwrap_or(CapturePowerCommand::Unspecified)
        {
            CapturePowerCommand::Auto => self.capture_power.set_auto().await,
            CapturePowerCommand::ForceOn => self.capture_power.set_manual(true).await,
            CapturePowerCommand::ForceOff => self.capture_power.set_manual(false).await,
            CapturePowerCommand::Unspecified => self.capture_power.set_manual(req.enabled).await,
        };
        let state = result.map_err(|e| Status::internal(format!("{e:#}")))?;
        Ok(Response::new(
            self.with_detected_capture_devices(state).await,
        ))
    }
}

fn restart_uvc_helper() -> anyhow::Result<()> {
    if std::env::var("LESAVKA_GADGET_SYSFS_ROOT").is_ok()
        || std::env::var("LESAVKA_GADGET_CONFIGFS_ROOT").is_ok()
    {
        return Ok(());
    }

    run_systemctl(&["reset-failed", "lesavka-uvc.service"])?;
    match run_systemctl(&["restart", "lesavka-uvc.service"]) {
        Ok(()) => Ok(()),
        Err(err) if uvc_helper_restart_was_dependency_refused(&err.to_string()) => {
            warn!(
                "lesavka-uvc.service refused a direct restart because it is dependency-managed; USB reset already cycled the gadget"
            );
            Ok(())
        }
        Err(err) => Err(err),
    }
}

fn run_systemctl(args: &[&str]) -> anyhow::Result<()> {
    let output = Command::new("systemctl")
        .args(args)
        .output()
        .with_context(|| format!("running systemctl {}", args.join(" ")))?;
    if output.status.success() {
        return Ok(());
    }
    let stderr = String::from_utf8_lossy(&output.stderr).trim().to_string();
    let stdout = String::from_utf8_lossy(&output.stdout).trim().to_string();
    anyhow::bail!(
        "systemctl {} failed: {}{}",
        args.join(" "),
        if stderr.is_empty() {
            stdout.as_str()
        } else {
            stderr.as_str()
        },
        if stderr.is_empty() || stdout.is_empty() || stderr == stdout {
            ""
        } else {
            " / also see stdout"
        }
    );
}

fn uvc_helper_restart_was_dependency_refused(message: &str) -> bool {
    message.contains("Operation refused") || message.contains("may be requested by dependency only")
}

impl EyeHub {
    fn spawn<S>(mut stream: S, lease: lesavka_server::capture_power::CapturePowerLease) -> Arc<Self>
    where
        S: Stream<Item = Result<VideoPacket, Status>> + Unpin + Send + 'static,
    {
        let (tx, _) = broadcast::channel(32);
        let running = Arc::new(AtomicBool::new(true));
        let subscribers = Arc::new(AtomicUsize::new(0));
        let tx_for_task = tx.clone();
        let running_for_task = Arc::clone(&running);
        let subscribers_for_task = Arc::clone(&subscribers);
        let task = tokio::spawn(async move {
            let _lease = lease;
            let mut idle_ticks = 0_u32;
            while running_for_task.load(Ordering::Relaxed) {
                match stream.next().await {
                    Some(Ok(pkt)) => {
                        let _ = tx_for_task.send(pkt);
                        if subscribers_for_task.load(Ordering::Relaxed) == 0 {
                            idle_ticks = idle_ticks.saturating_add(1);
                            if idle_ticks >= 60 {
                                break;
                            }
                        } else {
                            idle_ticks = 0;
                        }
                    }
                    Some(Err(err)) => {
                        warn!(?err, "shared eye hub stream error");
                        break;
                    }
                    None => break,
                }
            }
            running_for_task.store(false, Ordering::Relaxed);
        });
        let hub = Arc::new(Self {
            tx: tx.clone(),
            running: Arc::clone(&running),
            subscribers: Arc::clone(&subscribers),
            abort: task.abort_handle(),
        });

        hub
    }

    fn shutdown(&self) {
        if self.running.swap(false, Ordering::AcqRel) {
            self.abort.abort();
        }
    }
}

fn take_conflicting_eye_hubs(
    hubs: &mut HashMap<EyeHubKey, Arc<EyeHub>>,
    key: EyeHubKey,
) -> Vec<Arc<EyeHub>> {
    let stale_keys: Vec<_> = hubs
        .iter()
        .filter_map(|(existing_key, hub)| {
            let running = hub.running.load(Ordering::Relaxed);
            let conflicting_source =
                existing_key.source_id == key.source_id && *existing_key != key;
            if !running || conflicting_source {
                Some(*existing_key)
            } else {
                None
            }
        })
        .collect();

    stale_keys
        .into_iter()
        .filter_map(|existing_key| hubs.remove(&existing_key))
        .collect()
}

/*──────────────── gRPC service ─────────────*/
#[cfg(not(coverage))]
#[tonic::async_trait]
impl Relay for Handler {
    /* existing streams ─ unchanged, except: no more auto-reset */
    type StreamKeyboardStream = ReceiverStream<Result<KeyboardReport, Status>>;
    type StreamMouseStream = ReceiverStream<Result<MouseReport, Status>>;
    type CaptureVideoStream = VideoStream;
    type CaptureAudioStream = AudioStream;
    type StreamMicrophoneStream = ReceiverStream<Result<Empty, Status>>;
    type StreamCameraStream = ReceiverStream<Result<Empty, Status>>;

    async fn stream_keyboard(
        &self,
        req: Request<tonic::Streaming<KeyboardReport>>,
    ) -> Result<Response<Self::StreamKeyboardStream>, Status> {
        let rpc_id = runtime_support::next_stream_id();
        info!(rpc_id, "⌨️ stream_keyboard opened");
        let (tx, rx) = tokio::sync::mpsc::channel(32);
        let kb = self.kb.clone();
        let ms = self.ms.clone();
        let kb_path = hid_endpoint(0);
        let ms_path = hid_endpoint(1);
        let gadget = self.gadget.clone();
        let did_cycle = self.did_cycle.clone();
        let session_lease = self.capture_power.acquire_session().await;
        let report_delay = live_keyboard_report_delay();

        tokio::spawn(async move {
            let _session_lease = session_lease;
            let mut s = req.into_inner();
            while let Some(pkt) = s.next().await.transpose()? {
                if let Err(e) = runtime_support::write_hid_report(&kb, &kb_path, &pkt.data).await {
                    if e.raw_os_error() == Some(libc::EAGAIN) {
                        debug!(rpc_id, "⌨️  write would block (dropped)");
                    } else {
                        warn!(rpc_id, "⌨️  write failed: {e} (dropped)");
                        runtime_support::recover_hid_if_needed(
                            &e,
                            gadget.clone(),
                            kb.clone(),
                            ms.clone(),
                            kb_path.clone(),
                            ms_path.clone(),
                            did_cycle.clone(),
                        )
                        .await;
                    }
                }
                tx.send(Ok(pkt)).await.ok();
                if !report_delay.is_zero() {
                    tokio::time::sleep(report_delay).await;
                }
            }
            info!(rpc_id, "⌨️ stream_keyboard closed");
            Ok::<(), Status>(())
        });

        Ok(Response::new(ReceiverStream::new(rx)))
    }

    async fn stream_mouse(
        &self,
        req: Request<tonic::Streaming<MouseReport>>,
    ) -> Result<Response<Self::StreamMouseStream>, Status> {
        let rpc_id = runtime_support::next_stream_id();
        info!(rpc_id, "🖱️ stream_mouse opened");
        let (tx, rx) = tokio::sync::mpsc::channel(1024);
        let ms = self.ms.clone();
        let kb = self.kb.clone();
        let kb_path = hid_endpoint(0);
        let ms_path = hid_endpoint(1);
        let gadget = self.gadget.clone();
        let did_cycle = self.did_cycle.clone();
        let session_lease = self.capture_power.acquire_session().await;

        tokio::spawn(async move {
            let _session_lease = session_lease;
            let mut s = req.into_inner();
            while let Some(pkt) = s.next().await.transpose()? {
                if let Err(e) = runtime_support::write_hid_report(&ms, &ms_path, &pkt.data).await {
                    if e.raw_os_error() == Some(libc::EAGAIN) {
                        debug!(rpc_id, "🖱️  write would block (dropped)");
                    } else {
                        warn!(rpc_id, "🖱️  write failed: {e} (dropped)");
                        runtime_support::recover_hid_if_needed(
                            &e,
                            gadget.clone(),
                            kb.clone(),
                            ms.clone(),
                            kb_path.clone(),
                            ms_path.clone(),
                            did_cycle.clone(),
                        )
                        .await;
                    }
                }
                tx.send(Ok(pkt)).await.ok();
            }
            info!(rpc_id, "🖱️ stream_mouse closed");
            Ok::<(), Status>(())
        });

        Ok(Response::new(ReceiverStream::new(rx)))
    }

    /// Accept synthetic upstream microphone packets without ALSA hardware.
    async fn stream_microphone(
        &self,
        req: Request<tonic::Streaming<AudioPacket>>,
    ) -> Result<Response<Self::StreamMicrophoneStream>, Status> {
        let rpc_id = runtime_support::next_stream_id();
        info!(rpc_id, "🎤 stream_microphone opened");
        // 1 ─ build once, early
        let uac_dev = std::env::var("LESAVKA_UAC_DEV").unwrap_or_else(|_| "hw:UAC2Gadget,0".into());
        info!(%uac_dev, "🎤 stream_microphone using UAC sink");
        let mut sink = runtime_support::open_voice_with_retry(&uac_dev)
            .await
            .map_err(|e| Status::internal(format!("{e:#}")))?;

        // 2 ─ dummy outbound stream (same trick as before)
        let (tx, rx) = tokio::sync::mpsc::channel(1);

        // 3 ─ drive the sink in a background task
        tokio::spawn(async move {
            let mut inbound = req.into_inner();
            static CNT: std::sync::atomic::AtomicU64 = std::sync::atomic::AtomicU64::new(0);

            while let Some(pkt) = inbound.next().await.transpose()? {
                let n = CNT.fetch_add(1, std::sync::atomic::Ordering::Relaxed);
                if n < 5 || n % 3_000 == 0 {
                    tracing::info!(rpc_id, "🎤⬇ srv  pkt#{n}  {} bytes", pkt.data.len());
                }
                sink.push(&pkt);
            }
            sink.finish(); // flush on EOS
            let _ = tx.send(Ok(Empty {})).await;
            info!(rpc_id, "🎤 stream_microphone closed");
            Ok::<(), Status>(())
        });

        Ok(Response::new(ReceiverStream::new(rx)))
    }

    /// Accept synthetic upstream webcam packets without UVC/HDMI hardware.
    async fn stream_camera(
        &self,
        req: Request<tonic::Streaming<VideoPacket>>,
    ) -> Result<Response<Self::StreamCameraStream>, Status> {
        let rpc_id = runtime_support::next_stream_id();
        let cfg = camera::current_camera_config();
        info!(
            rpc_id,
            output = cfg.output.as_str(),
            codec = cfg.codec.as_str(),
            width = cfg.width,
            height = cfg.height,
            fps = cfg.fps,
            hdmi = cfg.hdmi.as_ref().map(|h| h.name.as_str()).unwrap_or("none"),
            "🎥 stream_camera output selected"
        );

        let (session_id, relay) = self.camera_rt.activate(&cfg).await?;
        let camera_rt = self.camera_rt.clone();
        info!(rpc_id, session_id, "🎥 stream_camera opened");

        // dummy outbound (same pattern as other streams)
        let (tx, rx) = tokio::sync::mpsc::channel(1);

        tokio::spawn(async move {
            let mut s = req.into_inner();
            while let Some(pkt) = s.next().await.transpose()? {
                if !camera_rt.is_active(session_id) {
                    info!(rpc_id, session_id, "🎥 stream_camera session superseded");
                    break;
                }
                relay.feed(pkt); // ← all logging inside video.rs
            }
            tx.send(Ok(Empty {})).await.ok();
            info!(rpc_id, session_id, "🎥 stream_camera closed");
            Ok::<(), Status>(())
        });

        Ok(Response::new(ReceiverStream::new(rx)))
    }

    async fn capture_video(
        &self,
        req: Request<MonitorRequest>,
    ) -> Result<Response<Self::CaptureVideoStream>, Status> {
        self.capture_video_reply(req.into_inner()).await
    }

    async fn capture_audio(
        &self,
        req: Request<MonitorRequest>,
    ) -> Result<Response<Self::CaptureAudioStream>, Status> {
        let rpc_id = runtime_support::next_stream_id();
        // Only one speaker stream for now; both 0/1 → same ALSA dev.
        let _id = req.into_inner().id;
        // Allow override (`LESAVKA_ALSA_DEV=hw:2,0` for debugging).
        let dev = std::env::var("LESAVKA_ALSA_DEV").unwrap_or_else(|_| "hw:UAC2Gadget,0".into());
        info!(rpc_id, %dev, "🔊 capture_audio opened");

        let s = runtime_support::open_ear_with_retry(&dev, 0)
            .await
            .map_err(|e| remote_audio_status(format!("{e:#}")))?;

        Ok(Response::new(Box::pin(s)))
    }

    async fn paste_text(&self, req: Request<PasteRequest>) -> Result<Response<PasteReply>, Status> {
        self.paste_text_reply(req).await
    }

    /*────────────── USB-reset RPC ────────────*/
    async fn reset_usb(&self, _req: Request<Empty>) -> Result<Response<ResetUsbReply>, Status> {
        self.reset_usb_reply().await
    }

    async fn get_capture_power(
        &self,
        _req: Request<Empty>,
    ) -> Result<Response<CapturePowerState>, Status> {
        self.get_capture_power_reply().await
    }

    async fn set_capture_power(
        &self,
        req: Request<SetCapturePowerRequest>,
    ) -> Result<Response<CapturePowerState>, Status> {
        self.set_capture_power_reply(req).await
    }
}

fn remote_audio_status(message: String) -> Status {
    if message.contains("remote USB gadget is not attached") {
        Status::unavailable(message)
    } else {
        Status::internal(message)
    }
}

#[cfg(coverage)]
#[tonic::async_trait]
impl Relay for Handler {
    type StreamKeyboardStream = ReceiverStream<Result<KeyboardReport, Status>>;
    type StreamMouseStream = ReceiverStream<Result<MouseReport, Status>>;
    type CaptureVideoStream = VideoStream;
    type CaptureAudioStream = AudioStream;
    type StreamMicrophoneStream = ReceiverStream<Result<Empty, Status>>;
    type StreamCameraStream = ReceiverStream<Result<Empty, Status>>;

    async fn stream_keyboard(
        &self,
        req: Request<tonic::Streaming<KeyboardReport>>,
    ) -> Result<Response<Self::StreamKeyboardStream>, Status> {
        let (tx, rx) = tokio::sync::mpsc::channel(32);
        let kb = self.kb.clone();
        let report_delay = live_keyboard_report_delay();

        tokio::spawn(async move {
            let mut s = req.into_inner();
            while let Some(pkt) = s.next().await.transpose()? {
                let _ = runtime_support::write_hid_report(&kb, &hid_endpoint(0), &pkt.data).await;
                tx.send(Ok(pkt)).await.ok();
                if !report_delay.is_zero() {
                    tokio::time::sleep(report_delay).await;
                }
            }
            Ok::<(), Status>(())
        });

        Ok(Response::new(ReceiverStream::new(rx)))
    }

    async fn stream_mouse(
        &self,
        req: Request<tonic::Streaming<MouseReport>>,
    ) -> Result<Response<Self::StreamMouseStream>, Status> {
        let (tx, rx) = tokio::sync::mpsc::channel(32);
        let ms = self.ms.clone();

        tokio::spawn(async move {
            let mut s = req.into_inner();
            while let Some(pkt) = s.next().await.transpose()? {
                let _ = runtime_support::write_hid_report(&ms, &hid_endpoint(1), &pkt.data).await;
                tx.send(Ok(pkt)).await.ok();
            }
            Ok::<(), Status>(())
        });

        Ok(Response::new(ReceiverStream::new(rx)))
    }

    async fn stream_microphone(
        &self,
        req: Request<tonic::Streaming<AudioPacket>>,
    ) -> Result<Response<Self::StreamMicrophoneStream>, Status> {
        let uac_dev = std::env::var("LESAVKA_UAC_DEV").unwrap_or_else(|_| "hw:UAC2Gadget,0".into());
        let mut sink = runtime_support::open_voice_with_retry(&uac_dev)
            .await
            .map_err(|e| Status::internal(format!("{e:#}")))?;
        let (tx, rx) = tokio::sync::mpsc::channel(1);

        tokio::spawn(async move {
            let mut inbound = req.into_inner();
            while let Some(pkt) = inbound.next().await.transpose()? {
                sink.push(&pkt);
            }
            sink.finish();
            let _ = tx.send(Ok(Empty {})).await;
            Ok::<(), Status>(())
        });

        Ok(Response::new(ReceiverStream::new(rx)))
    }

    async fn stream_camera(
        &self,
        req: Request<tonic::Streaming<VideoPacket>>,
    ) -> Result<Response<Self::StreamCameraStream>, Status> {
        let cfg = camera::current_camera_config();
        let (session_id, relay) = self.camera_rt.activate(&cfg).await?;
        let camera_rt = self.camera_rt.clone();
        let (tx, rx) = tokio::sync::mpsc::channel(1);

        tokio::spawn(async move {
            let mut s = req.into_inner();
            while let Some(pkt) = s.next().await.transpose()? {
                if !camera_rt.is_active(session_id) {
                    break;
                }
                relay.feed(pkt);
            }
            tx.send(Ok(Empty {})).await.ok();
            Ok::<(), Status>(())
        });

        Ok(Response::new(ReceiverStream::new(rx)))
    }

    async fn capture_video(
        &self,
        req: Request<MonitorRequest>,
    ) -> Result<Response<Self::CaptureVideoStream>, Status> {
        self.capture_video_reply(req.into_inner()).await
    }

    async fn capture_audio(
        &self,
        _req: Request<MonitorRequest>,
    ) -> Result<Response<Self::CaptureAudioStream>, Status> {
        Err(Status::internal(
            "audio capture unavailable in coverage harness",
        ))
    }

    async fn paste_text(&self, req: Request<PasteRequest>) -> Result<Response<PasteReply>, Status> {
        self.paste_text_reply(req).await
    }

    async fn reset_usb(&self, _req: Request<Empty>) -> Result<Response<ResetUsbReply>, Status> {
        self.reset_usb_reply().await
    }

    async fn get_capture_power(
        &self,
        _req: Request<Empty>,
    ) -> Result<Response<CapturePowerState>, Status> {
        self.get_capture_power_reply().await
    }

    async fn set_capture_power(
        &self,
        req: Request<SetCapturePowerRequest>,
    ) -> Result<Response<CapturePowerState>, Status> {
        self.set_capture_power_reply(req).await
    }
}

/*──────────────── main ───────────────────────*/
#[cfg(not(coverage))]
#[tokio::main(worker_threads = 4)]
async fn main() -> anyhow::Result<()> {
    let _guard = init_tracing()?;
    info!("🚀 {} v{} starting up", PKG_NAME, lesavka_server::VERSION);

    panic::set_hook(Box::new(|p| {
        let bt = Backtrace::force_capture();
        error!("💥 panic: {p}\n{bt}");
    }));

    let gadget = UsbGadget::new("lesavka");
    if std::env::var("LESAVKA_DISABLE_UVC").is_err() {
        if std::env::var("LESAVKA_UVC_EXTERNAL").is_ok() {
            info!("📷 UVC control helper external; not spawning");
        } else {
            let bin = uvc_runtime::uvc_ctrl_bin();
            tokio::spawn(uvc_runtime::supervise_uvc_control(bin));
        }
    } else {
        info!("📷 UVC disabled (LESAVKA_DISABLE_UVC set)");
    }
    let handler = Handler::new(gadget.clone()).await?;

    info!("🌐 lesavka-server listening on 0.0.0.0:50051");
    Server::builder()
        .tcp_nodelay(true)
        .max_frame_size(Some(2 * 1024 * 1024))
        .add_service(RelayServer::new(handler))
        .add_service(HandshakeSvc::server())
        .add_service(ReflBuilder::configure().build_v1().unwrap())
        .serve(([0, 0, 0, 0], 50051).into())
        .await?;
    Ok(())
}

#[cfg(coverage)]
#[tokio::main(worker_threads = 2)]
async fn main() -> anyhow::Result<()> {
    let gadget = UsbGadget::new("lesavka");
    let _handler = Handler::new(gadget).await?;
    Err(anyhow::anyhow!("coverage mode skips live gRPC serve loop"))
}