//! [`WebRtcStreamer`]: shared [`SharedVideoPipeline`], multiplex [`UniversalSession`] (video/audio/HID DC).

use std::collections::HashMap;
use std::path::PathBuf;
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::{Arc, RwLock as StdRwLock};
use tokio::sync::RwLock;
use tracing::{debug, info, trace, warn};

use crate::audio::{AudioController, OpusFrame};
use crate::error::{AppError, Result};
use crate::events::{EventBus, SystemEvent};
use crate::hid::HidController;
use crate::video::device::{
    enumerate_devices, select_recovery_device, VideoDevice, VideoDeviceRecoveryHint,
};
use crate::video::types::{
    BitratePreset, EncoderBackend, PipelineStateNotification, PixelFormat, Resolution,
    SharedVideoPipeline, SharedVideoPipelineConfig, SharedVideoPipelineStats, VideoCodecType,
    VideoEncoderType,
};

use super::config::{TurnServer, WebRtcConfig};
use super::signaling::{ConnectionState, IceCandidate, SdpAnswer, SdpOffer};
use super::universal_session::{UniversalSession, UniversalSessionConfig};

#[derive(Debug, Clone)]
pub struct WebRtcStreamerConfig {
    pub webrtc: WebRtcConfig,
    pub video_codec: VideoCodecType,
    pub resolution: Resolution,
    pub input_format: PixelFormat,
    pub bitrate_preset: BitratePreset,
    pub fps: u32,
    pub audio_enabled: bool,
    pub encoder_backend: Option<EncoderBackend>,
}

impl Default for WebRtcStreamerConfig {
    fn default() -> Self {
        Self {
            webrtc: WebRtcConfig::default(),
            video_codec: VideoCodecType::H264,
            resolution: Resolution::HD720,
            input_format: PixelFormat::Mjpeg,
            bitrate_preset: BitratePreset::Balanced,
            fps: 30,
            audio_enabled: false,
            encoder_backend: None,
        }
    }
}

#[derive(Debug, Clone)]
pub struct CaptureDeviceConfig {
    pub device_path: PathBuf,
    pub buffer_count: u32,
    pub jpeg_quality: u8,
    pub subdev_path: Option<PathBuf>,
    pub bridge_kind: Option<String>,
    /// V4L2 driver name (e.g. `uvcvideo`) for UVC-specific recovery hints.
    pub v4l2_driver: Option<String>,
    pub recovery_hint: VideoDeviceRecoveryHint,
}

#[derive(Debug, Clone, Default)]
pub struct WebRtcStreamerStats {
    pub session_count: usize,
    pub video_codec: String,
    pub video_pipeline: Option<VideoPipelineStats>,
    pub audio_enabled: bool,
}

#[derive(Debug, Clone, Default)]
pub struct VideoPipelineStats {
    pub current_fps: f32,
}

#[derive(Debug, Clone)]
pub struct SessionInfo {
    pub session_id: String,
    pub created_at: std::time::Instant,
    pub state: String,
}

pub struct WebRtcStreamer {
    config: RwLock<WebRtcStreamerConfig>,
    video_codec: RwLock<VideoCodecType>,
    video_pipeline: RwLock<Option<Arc<SharedVideoPipeline>>>,
    sessions: Arc<RwLock<HashMap<String, Arc<UniversalSession>>>>,
    capture_device: RwLock<Option<CaptureDeviceConfig>>,
    audio_enabled: RwLock<bool>,
    audio_controller: RwLock<Option<Arc<AudioController>>>,
    hid_controller: RwLock<Option<Arc<HidController>>>,
    events: RwLock<Option<Arc<EventBus>>>,
    recovery_in_progress: AtomicBool,
    self_weak: StdRwLock<Option<std::sync::Weak<Self>>>,
}

impl WebRtcStreamer {
    pub fn new() -> Arc<Self> {
        Self::with_config(WebRtcStreamerConfig::default())
    }

    pub fn with_config(config: WebRtcStreamerConfig) -> Arc<Self> {
        let streamer = Arc::new(Self {
            config: RwLock::new(config.clone()),
            video_codec: RwLock::new(config.video_codec),
            video_pipeline: RwLock::new(None),
            sessions: Arc::new(RwLock::new(HashMap::new())),
            capture_device: RwLock::new(None),
            audio_enabled: RwLock::new(config.audio_enabled),
            audio_controller: RwLock::new(None),
            hid_controller: RwLock::new(None),
            events: RwLock::new(None),
            recovery_in_progress: AtomicBool::new(false),
            self_weak: StdRwLock::new(None),
        });
        let weak = Arc::downgrade(&streamer);
        *streamer.self_weak.write().expect("self_weak write") = Some(weak);
        streamer
    }

    fn self_weak(&self) -> std::sync::Weak<Self> {
        self.self_weak
            .read()
            .expect("self_weak read")
            .as_ref()
            .expect("WebRtcStreamer: self_weak must be initialized in with_config")
            .clone()
    }

    pub async fn current_video_codec(&self) -> VideoCodecType {
        *self.video_codec.read().await
    }

    /// Set video codec type
    ///
    /// Supports H264, H265, VP8, VP9. This will restart the video pipeline
    /// and close all existing sessions.
    pub async fn set_video_codec(&self, codec: VideoCodecType) -> Result<()> {
        let current = *self.video_codec.read().await;
        if current == codec {
            return Ok(());
        }

        info!("Switching video codec from {:?} to {:?}", current, codec);

        // Close all existing sessions
        self.close_all_sessions().await;

        // Stop current pipeline
        if let Some(ref pipeline) = *self.video_pipeline.read().await {
            pipeline.stop();
        }
        *self.video_pipeline.write().await = None;

        // Update codec
        *self.video_codec.write().await = codec;

        // Create new pipeline with new codec if capture source is configured
        let has_capture = self.capture_device.read().await.is_some();
        if has_capture {
            self.ensure_video_pipeline().await?;
        }

        info!("Video codec switched to {:?}", codec);
        Ok(())
    }

    /// Get list of supported video codecs
    pub fn supported_video_codecs(&self) -> Vec<VideoCodecType> {
        use crate::video::encoder::registry::EncoderRegistry;

        let registry = EncoderRegistry::global();
        VideoEncoderType::ordered()
            .into_iter()
            .filter(|codec| registry.is_codec_available(*codec))
            .map(Self::encoder_type_to_codec_type)
            .collect()
    }

    /// Convert VideoCodecType to VideoEncoderType
    fn codec_type_to_encoder_type(codec: VideoCodecType) -> VideoEncoderType {
        match codec {
            VideoCodecType::H264 => VideoEncoderType::H264,
            VideoCodecType::H265 => VideoEncoderType::H265,
            VideoCodecType::VP8 => VideoEncoderType::VP8,
            VideoCodecType::VP9 => VideoEncoderType::VP9,
        }
    }

    fn encoder_type_to_codec_type(codec: VideoEncoderType) -> VideoCodecType {
        match codec {
            VideoEncoderType::H264 => VideoCodecType::H264,
            VideoEncoderType::H265 => VideoCodecType::H265,
            VideoEncoderType::VP8 => VideoCodecType::VP8,
            VideoEncoderType::VP9 => VideoCodecType::VP9,
        }
    }

    fn should_stop_pipeline(session_count: usize, subscriber_count: usize) -> bool {
        session_count == 0 && subscriber_count == 0
    }

    async fn stop_pipeline_if_idle(&self, reason: &str) {
        let session_count = self.sessions.read().await.len();
        let pipeline = self.video_pipeline.read().await.clone();

        let Some(pipeline) = pipeline else {
            return;
        };

        let subscriber_count = pipeline.subscriber_count();
        if Self::should_stop_pipeline(session_count, subscriber_count) {
            info!(
                "{} stopping video pipeline (sessions={}, subscribers={})",
                reason, session_count, subscriber_count
            );
            pipeline.stop();
        } else {
            debug!(
                "Keeping video pipeline alive (reason={}, sessions={}, subscribers={})",
                reason, session_count, subscriber_count
            );
        }
    }

    fn build_pipeline_state_notifier(
        device: String,
        events: Option<Arc<EventBus>>,
    ) -> Option<Arc<dyn Fn(PipelineStateNotification) + Send + Sync>> {
        events.map(|events| {
            Arc::new(move |notification: PipelineStateNotification| {
                events.publish(SystemEvent::StreamStateChanged {
                    state: notification.state.to_string(),
                    device: Some(device.clone()),
                    reason: notification.reason.map(|reason| reason.to_string()),
                    next_retry_ms: notification.next_retry_ms,
                });
            }) as Arc<dyn Fn(PipelineStateNotification) + Send + Sync>
        })
    }

    fn make_keyframe_callback(
        pipeline: Arc<SharedVideoPipeline>,
        session_id: String,
    ) -> Arc<dyn Fn() + Send + Sync + 'static> {
        Arc::new(move || {
            let pipeline = pipeline.clone();
            let sid = session_id.clone();
            tokio::spawn(async move {
                info!("Requesting keyframe for session {} after reconnect", sid);
                pipeline.request_keyframe().await;
            });
        })
    }

    async fn reconnect_sessions_to_current_pipeline(&self, reason: &str) -> Result<usize> {
        if self.capture_device.read().await.is_none() {
            return Ok(0);
        }

        let sessions_to_reconnect: Vec<(String, Arc<UniversalSession>)> = {
            let sessions = self.sessions.read().await;
            sessions
                .iter()
                .map(|(session_id, session)| (session_id.clone(), session.clone()))
                .collect()
        };

        if sessions_to_reconnect.is_empty() {
            return Ok(0);
        }

        let pipeline = self.ensure_video_pipeline().await?;
        for (session_id, session) in &sessions_to_reconnect {
            info!(
                "Reconnecting session {} to pipeline after {}",
                session_id, reason
            );
            session
                .start_from_video_pipeline(
                    pipeline.subscribe(),
                    Self::make_keyframe_callback(pipeline.clone(), session_id.clone()),
                )
                .await;
        }

        Ok(sessions_to_reconnect.len())
    }

    async fn publish_stream_event(&self, event: SystemEvent) {
        if let Some(events) = self.events.read().await.as_ref() {
            events.publish(event);
            events.mark_device_info_dirty();
        }
    }

    async fn update_recovered_capture_device(
        &self,
        device: crate::video::device::VideoDeviceInfo,
    ) -> Result<()> {
        let (format, resolution, fps, jpeg_quality, buffer_count) = {
            let config = self.config.read().await;
            let current_capture = self.capture_device.read().await.clone();
            (
                config.input_format,
                config.resolution,
                config.fps,
                current_capture
                    .as_ref()
                    .map(|capture| capture.jpeg_quality)
                    .unwrap_or(80),
                current_capture
                    .as_ref()
                    .map(|capture| capture.buffer_count)
                    .unwrap_or(2),
            )
        };

        let pipeline_config = CaptureDeviceConfig {
            device_path: device.path.clone(),
            buffer_count,
            jpeg_quality,
            subdev_path: device.subdev_path.clone(),
            bridge_kind: device.bridge_kind.clone(),
            v4l2_driver: Some(device.driver.clone()),
            recovery_hint: VideoDeviceRecoveryHint::from(&device),
        };

        *self.capture_device.write().await = Some(pipeline_config);
        let mut config = self.config.write().await;
        config.input_format = format;
        config.resolution = resolution;
        config.fps = fps;
        Ok(())
    }

    fn start_device_recovery(self: &Arc<Self>, hint: VideoDeviceRecoveryHint, reason: String) {
        if self.recovery_in_progress.swap(true, Ordering::SeqCst) {
            debug!("WebRTC video recovery already in progress");
            return;
        }

        let streamer = self.clone();
        tokio::spawn(async move {
            let original_device = hint.path.display().to_string();
            warn!(
                "WebRTC video recovery started for {}: {}",
                original_device, reason
            );
            streamer
                .publish_stream_event(SystemEvent::StreamDeviceLost {
                    device: original_device.clone(),
                    reason: reason.clone(),
                })
                .await;

            let mut attempt = 0u32;
            loop {
                attempt = attempt.saturating_add(1);
                streamer
                    .publish_stream_event(SystemEvent::StreamReconnecting {
                        device: original_device.clone(),
                        attempt,
                    })
                    .await;
                streamer
                    .publish_stream_event(SystemEvent::StreamStateChanged {
                        state: "device_lost".to_string(),
                        device: Some(original_device.clone()),
                        reason: Some("recovering".to_string()),
                        next_retry_ms: Some(1_000),
                    })
                    .await;

                tokio::time::sleep(std::time::Duration::from_secs(1)).await;

                let devices = match enumerate_devices() {
                    Ok(devices) => devices,
                    Err(e) => {
                        debug!("WebRTC video recovery enumerate failed: {}", e);
                        continue;
                    }
                };

                let Some(device) = select_recovery_device(&devices, &hint) else {
                    debug!("No matching WebRTC video device found during recovery");
                    continue;
                };

                if let Err(e) = streamer
                    .update_recovered_capture_device(device.clone())
                    .await
                {
                    debug!("Failed to update recovered capture device: {}", e);
                    continue;
                }

                match streamer.ensure_video_pipeline().await {
                    Ok(_) => {
                        match streamer
                            .reconnect_sessions_to_current_pipeline("device recovery")
                            .await
                        {
                            Ok(reconnected) => {
                                info!(
                                    "WebRTC video recovered with {} after {} attempts, reconnected {} sessions",
                                    device.path.display(),
                                    attempt,
                                    reconnected
                                );
                                streamer
                                    .publish_stream_event(SystemEvent::StreamRecovered {
                                        device: device.path.display().to_string(),
                                    })
                                    .await;
                                streamer
                                    .publish_stream_event(SystemEvent::StreamStateChanged {
                                        state: "streaming".to_string(),
                                        device: Some(device.path.display().to_string()),
                                        reason: None,
                                        next_retry_ms: None,
                                    })
                                    .await;
                                streamer.recovery_in_progress.store(false, Ordering::SeqCst);
                                return;
                            }
                            Err(e) => {
                                debug!("Failed to reconnect WebRTC sessions after recovery: {}", e);
                            }
                        }
                    }
                    Err(e) => {
                        debug!("Failed to restart WebRTC video pipeline: {}", e);
                    }
                }
            }
        });
    }

    /// Ensure video pipeline is initialized and running
    async fn ensure_video_pipeline(&self) -> Result<Arc<SharedVideoPipeline>> {
        let mut pipeline_guard = self.video_pipeline.write().await;

        if let Some(ref pipeline) = *pipeline_guard {
            if pipeline.is_running() {
                return Ok(pipeline.clone());
            }
        }

        let codec = *self.video_codec.read().await;
        let pipeline_config = {
            let config = self.config.read().await;
            SharedVideoPipelineConfig {
                resolution: config.resolution,
                input_format: config.input_format,
                output_codec: Self::codec_type_to_encoder_type(codec),
                bitrate_preset: config.bitrate_preset,
                fps: config.fps,
                encoder_backend: config.encoder_backend,
            }
        };

        info!("Creating shared video pipeline for {:?}", codec);
        let pipeline = SharedVideoPipeline::new(pipeline_config)?;
        let capture_device = self.capture_device.read().await.clone();
        if let Some(device) = capture_device {
            pipeline.set_state_notifier(Self::build_pipeline_state_notifier(
                device.device_path.display().to_string(),
                self.events.read().await.clone(),
            ));
            pipeline
                .start_with_device(
                    device.device_path,
                    device.buffer_count,
                    device.jpeg_quality,
                    device.subdev_path,
                    device.bridge_kind,
                    device.v4l2_driver,
                )
                .await?;
        } else {
            return Err(AppError::VideoError(
                "No capture device configured".to_string(),
            ));
        }

        // Start a monitor task to detect when pipeline auto-stops
        let pipeline_weak = Arc::downgrade(&pipeline);
        let streamer_weak = self.self_weak();
        let mut running_rx = pipeline.running_watch();

        tokio::spawn(async move {
            // Wait for pipeline to stop (running becomes false)
            while running_rx.changed().await.is_ok() {
                if !*running_rx.borrow() {
                    info!("Video pipeline auto-stopped, cleaning up resources");

                    // Clear pipeline reference in WebRtcStreamer
                    if let Some(streamer) = streamer_weak.upgrade() {
                        let mut pending_geometry: Option<(Resolution, PixelFormat)> = None;
                        let mut device_lost_reason: Option<String> = None;
                        let mut pipeline_guard = streamer.video_pipeline.write().await;
                        // Only clear if it's the same pipeline that stopped
                        if let Some(ref current) = *pipeline_guard {
                            if let Some(stopped_pipeline) = pipeline_weak.upgrade() {
                                if Arc::ptr_eq(current, &stopped_pipeline) {
                                    pending_geometry =
                                        stopped_pipeline.take_pending_sync_geometry();
                                    device_lost_reason = stopped_pipeline.take_device_lost_reason();
                                    *pipeline_guard = None;
                                    info!("Cleared stopped video pipeline reference");
                                }
                            }
                        }
                        drop(pipeline_guard);

                        if let Some(reason) = device_lost_reason {
                            if let Some(capture) = streamer.capture_device.read().await.clone() {
                                streamer.start_device_recovery(capture.recovery_hint, reason);
                            }
                            continue;
                        }

                        let should_reconnect = pending_geometry.is_some();
                        if let Some((r, f)) = pending_geometry {
                            streamer.sync_video_geometry_from_negotiated(r, f).await;
                        }
                        if should_reconnect {
                            let streamer_for_reconnect = streamer.clone();
                            tokio::task::spawn_blocking(move || {
                                let handle = tokio::runtime::Handle::current();
                                handle.block_on(async move {
                                    match streamer_for_reconnect
                                        .reconnect_sessions_to_current_pipeline(
                                            "capture geometry change",
                                        )
                                        .await
                                    {
                                        Ok(reconnected) if reconnected > 0 => info!(
                                            "Video pipeline rebuilt after geometry change, reconnected {} sessions",
                                            reconnected
                                        ),
                                        Ok(_) => {}
                                        Err(e) => warn!(
                                            "Failed to reconnect sessions after geometry change: {}",
                                            e
                                        ),
                                    }
                                });
                            });
                        }

                        info!(
                            "Video pipeline stopped, but keeping capture config for new sessions"
                        );
                    }
                    break;
                }
            }
            debug!("Video pipeline monitor task ended");
        });

        let pipeline_cfg = pipeline.config().await;
        self.sync_video_geometry_from_negotiated(
            pipeline_cfg.resolution,
            pipeline_cfg.input_format,
        )
        .await;

        *pipeline_guard = Some(pipeline.clone());
        Ok(pipeline)
    }

    /// Ensure video pipeline is running and return it for external consumers
    ///
    /// This is a public wrapper around ensure_video_pipeline for external
    /// components (like RustDesk) that need to share the encoded video stream.
    pub async fn ensure_video_pipeline_for_external(&self) -> Result<Arc<SharedVideoPipeline>> {
        self.ensure_video_pipeline().await
    }

    /// Get the current pipeline configuration (if pipeline is running)
    pub async fn get_pipeline_config(&self) -> Option<SharedVideoPipelineConfig> {
        if let Some(ref pipeline) = *self.video_pipeline.read().await {
            Some(pipeline.config().await)
        } else {
            None
        }
    }

    pub async fn current_video_geometry(&self) -> (Resolution, PixelFormat, u32) {
        if let Some(cfg) = self.get_pipeline_config().await {
            (cfg.resolution, cfg.input_format, cfg.fps)
        } else {
            let c = self.config.read().await;
            (c.resolution, c.input_format, c.fps)
        }
    }

    /// Request the encoder to generate a keyframe on next encode
    pub async fn request_keyframe(&self) -> Result<()> {
        if let Some(ref pipeline) = *self.video_pipeline.read().await {
            pipeline.request_keyframe().await;
            Ok(())
        } else {
            Err(AppError::VideoError(
                "Video pipeline not running".to_string(),
            ))
        }
    }

    // === Audio Management ===

    /// Check if audio is enabled
    pub async fn is_audio_enabled(&self) -> bool {
        *self.audio_enabled.read().await
    }

    /// Set audio enabled state
    pub async fn set_audio_enabled(&self, enabled: bool) -> Result<()> {
        let was_enabled = *self.audio_enabled.read().await;
        *self.audio_enabled.write().await = enabled;
        self.config.write().await.audio_enabled = enabled;

        if enabled && !was_enabled {
            // Reconnect audio for existing sessions if we have a controller
            if let Some(ref _controller) = *self.audio_controller.read().await {
                self.reconnect_audio_sources().await;
            }
        }

        debug!("WebRTC audio enabled: {}", enabled);
        Ok(())
    }

    /// Set audio controller reference
    pub async fn set_audio_controller(&self, controller: Arc<AudioController>) {
        debug!("Setting audio controller for WebRTC streamer");
        *self.audio_controller.write().await = Some(controller.clone());

        // Reconnect audio for existing sessions if audio is enabled
        if *self.audio_enabled.read().await {
            self.reconnect_audio_sources().await;
        }
    }

    /// Subscribe to encoded Opus frames (for sessions)
    pub async fn subscribe_opus(
        &self,
    ) -> Option<tokio::sync::mpsc::Receiver<std::sync::Arc<OpusFrame>>> {
        if let Some(ref controller) = *self.audio_controller.read().await {
            controller.subscribe_opus().await
        } else {
            None
        }
    }

    /// Reconnect audio source for all existing sessions
    /// Call this after audio controller restarts (e.g., quality change)
    pub async fn reconnect_audio_sources(&self) {
        if let Some(ref controller) = *self.audio_controller.read().await {
            let sessions = self.sessions.read().await;
            for (session_id, session) in sessions.iter() {
                if session.has_audio() {
                    info!("Reconnecting audio for session {}", session_id);
                    if let Some(rx) = controller.subscribe_opus().await {
                        session.start_audio_from_opus(rx).await;
                    }
                }
            }
        }
    }

    pub async fn set_capture_device(
        &self,
        device_path: PathBuf,
        jpeg_quality: u8,
        subdev_path: Option<PathBuf>,
        bridge_kind: Option<String>,
        v4l2_driver: Option<String>,
    ) {
        debug!(
            "Setting direct capture device for WebRTC: {:?} (subdev={:?}, kind={:?}, driver={:?})",
            device_path, subdev_path, bridge_kind, v4l2_driver
        );
        let recovery_hint = VideoDevice::open_readonly(&device_path)
            .and_then(|device| device.info())
            .map(|info| VideoDeviceRecoveryHint::from(&info))
            .unwrap_or_else(|_| VideoDeviceRecoveryHint {
                path: device_path.clone(),
                name: String::new(),
                driver: v4l2_driver.clone().unwrap_or_default(),
                bus_info: String::new(),
                card: String::new(),
                is_capture_card: true,
            });
        *self.capture_device.write().await = Some(CaptureDeviceConfig {
            device_path,
            buffer_count: 2,
            jpeg_quality,
            subdev_path,
            bridge_kind,
            v4l2_driver,
            recovery_hint,
        });
    }

    /// Clear direct capture device configuration
    pub async fn clear_capture_device(&self) {
        *self.capture_device.write().await = None;
    }

    /// Prepare for configuration change
    ///
    /// This stops the encoding pipeline and closes all sessions.
    pub async fn prepare_for_config_change(&self) {
        // Stop pipeline and close sessions - will be recreated on next session
        if let Some(ref pipeline) = *self.video_pipeline.read().await {
            pipeline.stop();
        }
        *self.video_pipeline.write().await = None;
        self.close_all_sessions().await;
    }

    // === Configuration ===

    /// Update video configuration
    ///
    /// Only restarts the encoding pipeline if configuration actually changed.
    /// This allows multiple consumers (WebRTC, RustDesk) to share the same pipeline
    /// without interrupting each other when they call this method with the same config.
    pub async fn update_video_config(&self, resolution: Resolution, format: PixelFormat, fps: u32) {
        // Check if configuration actually changed
        let config = self.config.read().await;
        let config_changed =
            config.resolution != resolution || config.input_format != format || config.fps != fps;
        drop(config);

        if !config_changed {
            // Configuration unchanged, no need to restart pipeline
            trace!(
                "Video config unchanged: {}x{} {:?} @ {} fps",
                resolution.width,
                resolution.height,
                format,
                fps
            );
            return;
        }

        // Configuration changed, restart pipeline
        info!(
            "Video config changed, restarting pipeline: {}x{} {:?} @ {} fps",
            resolution.width, resolution.height, format, fps
        );

        // Stop existing pipeline
        if let Some(ref pipeline) = *self.video_pipeline.read().await {
            pipeline.stop();
        }
        *self.video_pipeline.write().await = None;

        // Close all existing sessions - they need to reconnect
        let session_count = self.close_all_sessions().await;
        if session_count > 0 {
            info!(
                "Closed {} existing sessions due to config change",
                session_count
            );
        }

        // Update config (preserve user-configured bitrate)
        {
            let mut config = self.config.write().await;
            config.resolution = resolution;
            config.input_format = format;
            config.fps = fps;
            // Note: bitrate is NOT auto-scaled here - use set_bitrate() or config to change it

            info!(
                "WebRTC config updated: {}x{} {:?} @ {} fps, {}",
                resolution.width, resolution.height, format, fps, config.bitrate_preset
            );
        }

        self.notify_device_info_dirty().await;
    }

    /// Update resolution/format to match DV-negotiated capture without stopping
    /// the pipeline or closing sessions. Used when hardware timing differs from
    /// saved settings (e.g. RK628 `S_FMT` follows source while SQLite still has
    /// a user-chosen preset).
    pub async fn sync_video_geometry_from_negotiated(
        &self,
        resolution: Resolution,
        format: PixelFormat,
    ) {
        {
            let mut config = self.config.write().await;
            if config.resolution == resolution && config.input_format == format {
                return;
            }
            info!(
                "WebRTC geometry aligned to negotiated capture: {}x{} {:?} (was {}x{} {:?})",
                resolution.width,
                resolution.height,
                format,
                config.resolution.width,
                config.resolution.height,
                config.input_format
            );
            config.resolution = resolution;
            config.input_format = format;
        }

        self.notify_device_info_dirty().await;
    }

    /// Update encoder backend (software/hardware selection)
    pub async fn update_encoder_backend(&self, encoder_backend: Option<EncoderBackend>) {
        // Stop existing pipeline
        if let Some(ref pipeline) = *self.video_pipeline.read().await {
            pipeline.stop();
        }
        *self.video_pipeline.write().await = None;

        // Close all existing sessions - they need to reconnect with new encoder
        let session_count = self.close_all_sessions().await;
        if session_count > 0 {
            info!(
                "Closed {} existing sessions due to encoder backend change",
                session_count
            );
        }

        // Update config
        let mut config = self.config.write().await;
        config.encoder_backend = encoder_backend;

        info!("WebRTC encoder backend updated: {:?}", encoder_backend);
    }

    /// Check if current encoder configuration uses hardware encoding
    ///
    /// Returns true if:
    /// - A specific hardware backend is configured, OR
    /// - Auto mode is used and hardware encoders are available
    pub async fn is_hardware_encoding(&self) -> bool {
        let config = self.config.read().await;
        match config.encoder_backend {
            Some(backend) => backend.is_hardware(),
            None => {
                // Auto mode: check if hardware encoder is available for current codec
                use crate::video::encoder::registry::{EncoderRegistry, VideoEncoderType};
                let codec_type = match *self.video_codec.read().await {
                    VideoCodecType::H264 => VideoEncoderType::H264,
                    VideoCodecType::H265 => VideoEncoderType::H265,
                    VideoCodecType::VP8 => VideoEncoderType::VP8,
                    VideoCodecType::VP9 => VideoEncoderType::VP9,
                };
                EncoderRegistry::global()
                    .best_available_encoder(codec_type)
                    .map(|e| e.is_hardware)
                    .unwrap_or(false)
            }
        }
    }

    /// Update ICE configuration (STUN/TURN servers)
    ///
    /// Note: Changes take effect for new sessions only.
    /// Existing sessions need to be reconnected to use the new ICE config.
    ///
    /// If both stun_server and turn_server are empty/None, uses baked-in public STUN.
    pub async fn update_ice_config(
        &self,
        stun_server: Option<String>,
        turn_server: Option<String>,
        turn_username: Option<String>,
        turn_password: Option<String>,
    ) {
        let mut config = self.config.write().await;

        // Clear existing servers
        config.webrtc.stun_servers.clear();
        config.webrtc.turn_servers.clear();

        // Check if user configured custom servers
        let has_custom_stun = stun_server.as_ref().map(|s| !s.is_empty()).unwrap_or(false);
        let has_custom_turn = turn_server.as_ref().map(|s| !s.is_empty()).unwrap_or(false);

        // If no custom servers, use baked-in public STUN
        if !has_custom_stun && !has_custom_turn {
            use crate::webrtc::config::public_ice;
            let stun = public_ice::stun_server().to_string();
            info!("Using public STUN server: {}", stun);
            config.webrtc.stun_servers.push(stun);
        } else {
            // Use custom servers
            if let Some(ref stun) = stun_server {
                if !stun.is_empty() {
                    config.webrtc.stun_servers.push(stun.clone());
                    info!("Using custom STUN server: {}", stun);
                }
            }
            if let Some(ref turn) = turn_server {
                if !turn.is_empty() {
                    let username = turn_username.unwrap_or_default();
                    let credential = turn_password.unwrap_or_default();
                    config.webrtc.turn_servers.push(TurnServer::new(
                        turn.clone(),
                        username.clone(),
                        credential,
                    ));
                    info!("Using custom TURN server: {} (user: {})", turn, username);
                }
            }
        }
    }

    /// Set HID controller for DataChannel
    pub async fn set_hid_controller(&self, hid: Arc<HidController>) {
        *self.hid_controller.write().await = Some(hid);
    }

    /// Set event bus for WebRTC signaling events
    pub async fn set_event_bus(&self, events: Arc<EventBus>) {
        *self.events.write().await = Some(events);
    }

    /// Push a debounced `system.device_info` refresh so the console status card
    /// picks up DV-negotiated / pipeline resolution without a separate WebRTC message.
    async fn notify_device_info_dirty(&self) {
        if let Some(bus) = self.events.read().await.as_ref() {
            bus.mark_device_info_dirty();
        }
    }

    // === Session Management ===

    /// Create a new WebRTC session
    pub async fn create_session(&self) -> Result<String> {
        let session_id = uuid::Uuid::new_v4().to_string();
        let codec = *self.video_codec.read().await;

        // Ensure video pipeline is running
        let pipeline = self.ensure_video_pipeline().await?;

        // Create session config
        let config = self.config.read().await;
        let session_config = UniversalSessionConfig {
            webrtc: config.webrtc.clone(),
            codec: Self::codec_type_to_encoder_type(codec),
            resolution: config.resolution,
            input_format: config.input_format,
            bitrate_preset: config.bitrate_preset,
            fps: config.fps,
            audio_enabled: *self.audio_enabled.read().await,
        };
        drop(config);

        // Create universal session
        let event_bus = self.events.read().await.clone();
        let mut session =
            UniversalSession::new(session_config.clone(), session_id.clone(), event_bus).await?;

        // Set HID controller if available
        // Note: We DON'T create a data channel here - the frontend creates it.
        // The server only receives it via on_data_channel callback set in set_hid_controller().
        // If server also created a channel, frontend's ondatachannel would overwrite its
        // own channel with server's, but server's channel has no message handler!
        if let Some(ref hid) = *self.hid_controller.read().await {
            session.set_hid_controller(hid.clone());
        }

        let session = Arc::new(session);

        // Subscribe to video pipeline frames
        // Request keyframe after ICE connection is established and on gaps
        let pipeline_for_callback = pipeline.clone();
        let session_id_for_callback = session_id.clone();
        let request_keyframe =
            Self::make_keyframe_callback(pipeline_for_callback, session_id_for_callback);
        session
            .start_from_video_pipeline(pipeline.subscribe(), request_keyframe)
            .await;

        // Start audio if enabled
        if session_config.audio_enabled {
            if let Some(ref controller) = *self.audio_controller.read().await {
                if let Some(opus_rx) = controller.subscribe_opus().await {
                    session.start_audio_from_opus(opus_rx).await;
                }
            }
        }

        // Store session
        self.sessions
            .write()
            .await
            .insert(session_id.clone(), session);

        info!(
            "Session created: {} (codec={:?}, audio={}, {} total)",
            session_id,
            codec,
            session_config.audio_enabled,
            self.sessions.read().await.len()
        );

        Ok(session_id)
    }

    /// Handle SDP offer
    pub async fn handle_offer(&self, session_id: &str, offer: SdpOffer) -> Result<SdpAnswer> {
        let sessions = self.sessions.read().await;
        let session = sessions
            .get(session_id)
            .ok_or_else(|| AppError::NotFound(format!("Session not found: {}", session_id)))?;

        session.handle_offer(offer).await
    }

    /// Add ICE candidate
    pub async fn add_ice_candidate(&self, session_id: &str, candidate: IceCandidate) -> Result<()> {
        let sessions = self.sessions.read().await;
        let session = sessions
            .get(session_id)
            .ok_or_else(|| AppError::NotFound(format!("Session not found: {}", session_id)))?;

        session.add_ice_candidate(candidate).await
    }

    /// Close a session
    pub async fn close_session(&self, session_id: &str) -> Result<()> {
        let session = self.sessions.write().await.remove(session_id);

        if let Some(session) = session {
            session.close().await?;
        }

        self.stop_pipeline_if_idle("After close_session").await;

        Ok(())
    }

    /// Close all sessions
    pub async fn close_all_sessions(&self) -> usize {
        let mut sessions = self.sessions.write().await;
        let count = sessions.len();

        for (session_id, session) in sessions.drain() {
            debug!("Closing session {}", session_id);
            if let Err(e) = session.close().await {
                warn!("Error closing session {}: {}", session_id, e);
            }
        }

        drop(sessions);
        self.stop_pipeline_if_idle("After close_all_sessions").await;

        count
    }

    /// Close all sessions and wait for the video pipeline to fully release the
    /// capture device. Use this when the caller needs the V4L2 device immediately
    /// afterwards (e.g. switching to MJPEG mode).
    pub async fn close_all_sessions_and_release_device(&self) -> usize {
        let count = self.close_all_sessions().await;

        if let Some(ref pipeline) = *self.video_pipeline.read().await {
            pipeline
                .stop_and_wait(std::time::Duration::from_secs(3))
                .await;
        }
        *self.video_pipeline.write().await = None;

        count
    }

    /// Get session count
    pub async fn session_count(&self) -> usize {
        self.sessions.read().await.len()
    }

    /// Get session info
    pub async fn get_session(&self, session_id: &str) -> Option<SessionInfo> {
        let sessions = self.sessions.read().await;
        sessions.get(session_id).map(|s| SessionInfo {
            session_id: s.session_id.clone(),
            created_at: std::time::Instant::now(),
            state: format!("{}", s.state()),
        })
    }

    /// List all sessions
    pub async fn list_sessions(&self) -> Vec<SessionInfo> {
        self.sessions
            .read()
            .await
            .values()
            .map(|s| SessionInfo {
                session_id: s.session_id.clone(),
                created_at: std::time::Instant::now(),
                state: format!("{}", s.state()),
            })
            .collect()
    }

    /// Cleanup closed sessions
    pub async fn cleanup(&self) {
        let to_remove: Vec<String> = {
            let sessions = self.sessions.read().await;
            sessions
                .iter()
                .filter(|(_, s)| {
                    matches!(
                        s.state(),
                        ConnectionState::Closed
                            | ConnectionState::Failed
                            | ConnectionState::Disconnected
                    )
                })
                .map(|(id, _)| id.clone())
                .collect()
        };

        if !to_remove.is_empty() {
            let mut sessions = self.sessions.write().await;
            for id in &to_remove {
                debug!("Removing closed session: {}", id);
                sessions.remove(id);
            }

            drop(sessions);
            self.stop_pipeline_if_idle("After cleanup_closed_sessions")
                .await;
        }
    }

    // === Statistics ===

    /// Get streamer statistics
    pub async fn stats(&self) -> WebRtcStreamerStats {
        let codec = *self.video_codec.read().await;
        let session_count = self.session_count().await;

        let video_pipeline = if let Some(ref pipeline) = *self.video_pipeline.read().await {
            let s = pipeline.stats().await;
            Some(VideoPipelineStats {
                current_fps: s.current_fps,
            })
        } else {
            None
        };

        WebRtcStreamerStats {
            session_count,
            video_codec: format!("{:?}", codec),
            video_pipeline,
            audio_enabled: *self.audio_enabled.read().await,
        }
    }

    /// Get pipeline statistics
    pub async fn pipeline_stats(&self) -> Option<SharedVideoPipelineStats> {
        if let Some(ref pipeline) = *self.video_pipeline.read().await {
            Some(pipeline.stats().await)
        } else {
            None
        }
    }

    /// Set bitrate using preset
    ///
    /// Note: Hardware encoders (VAAPI, NVENC, etc.) don't support dynamic bitrate changes.
    /// This method restarts the pipeline to apply the new bitrate only if the preset actually changed.
    pub async fn set_bitrate_preset(&self, preset: BitratePreset) -> Result<()> {
        // Check if preset actually changed
        let current_preset = self.config.read().await.bitrate_preset;
        if current_preset == preset {
            trace!("Bitrate preset unchanged: {}", preset);
            return Ok(());
        }

        // Update config
        self.config.write().await.bitrate_preset = preset;

        // Check if pipeline exists and is running
        let pipeline_running = {
            if let Some(ref pipeline) = *self.video_pipeline.read().await {
                pipeline.is_running()
            } else {
                false
            }
        };

        if pipeline_running {
            info!("Restarting video pipeline to apply new bitrate: {}", preset);

            // Stop existing pipeline
            if let Some(ref pipeline) = *self.video_pipeline.read().await {
                pipeline.stop();
            }

            // Wait for pipeline to stop
            tokio::time::sleep(tokio::time::Duration::from_millis(100)).await;

            // Clear pipeline reference - will be recreated
            *self.video_pipeline.write().await = None;

            let has_source = self.capture_device.read().await.is_some();
            if !has_source {
                return Ok(());
            }

            let reconnected = self
                .reconnect_sessions_to_current_pipeline("bitrate change")
                .await?;
            if reconnected > 0 {
                info!(
                    "Video pipeline restarted with {}, reconnected {} sessions",
                    preset, reconnected
                );
            }
        } else {
            debug!(
                "Pipeline not running, bitrate {} will apply on next start",
                preset
            );
        }

        Ok(())
    }
}

#[async_trait::async_trait]
impl crate::video::traits::VideoOutput for WebRtcStreamer {
    async fn set_event_bus(&self, events: Arc<EventBus>) {
        self.set_event_bus(events).await;
    }

    async fn update_video_config(&self, resolution: Resolution, format: PixelFormat, fps: u32) {
        self.update_video_config(resolution, format, fps).await;
    }

    async fn set_capture_device(
        &self,
        device_path: PathBuf,
        jpeg_quality: u8,
        subdev_path: Option<PathBuf>,
        bridge_kind: Option<String>,
        v4l2_driver: Option<String>,
    ) {
        self.set_capture_device(
            device_path,
            jpeg_quality,
            subdev_path,
            bridge_kind,
            v4l2_driver,
        )
        .await;
    }

    async fn current_video_codec(&self) -> VideoCodecType {
        self.current_video_codec().await
    }

    async fn is_hardware_encoding(&self) -> bool {
        self.is_hardware_encoding().await
    }

    async fn close_all_sessions(&self) {
        self.close_all_sessions().await;
    }

    async fn close_all_sessions_and_release_device(&self) -> usize {
        self.close_all_sessions_and_release_device().await
    }

    async fn session_count(&self) -> usize {
        self.session_count().await
    }

    async fn set_hid_controller(&self, hid: Arc<HidController>) {
        self.set_hid_controller(hid).await;
    }

    async fn set_audio_enabled(&self, enabled: bool) -> Result<()> {
        self.set_audio_enabled(enabled).await
    }

    async fn is_audio_enabled(&self) -> bool {
        self.is_audio_enabled().await
    }

    async fn reconnect_audio_sources(&self) {
        self.reconnect_audio_sources().await;
    }

    async fn ensure_video_pipeline_for_external(&self) -> Result<Arc<SharedVideoPipeline>> {
        self.ensure_video_pipeline_for_external().await
    }

    async fn get_pipeline_config(&self) -> Option<SharedVideoPipelineConfig> {
        self.get_pipeline_config().await
    }

    async fn set_video_codec(&self, codec: VideoCodecType) -> Result<()> {
        self.set_video_codec(codec).await
    }

    async fn set_bitrate_preset(&self, preset: BitratePreset) -> Result<()> {
        self.set_bitrate_preset(preset).await
    }

    async fn request_keyframe(&self) -> Result<()> {
        self.request_keyframe().await
    }

    async fn current_video_geometry(&self) -> (Resolution, PixelFormat, u32) {
        self.current_video_geometry().await
    }

    async fn pipeline_stats(&self) -> Option<SharedVideoPipelineStats> {
        self.pipeline_stats().await
    }
}

impl Default for WebRtcStreamer {
    fn default() -> Self {
        Self {
            config: RwLock::new(WebRtcStreamerConfig::default()),
            video_codec: RwLock::new(VideoCodecType::H264),
            video_pipeline: RwLock::new(None),
            sessions: Arc::new(RwLock::new(HashMap::new())),
            capture_device: RwLock::new(None),
            audio_enabled: RwLock::new(false),
            audio_controller: RwLock::new(None),
            hid_controller: RwLock::new(None),
            events: RwLock::new(None),
            recovery_in_progress: AtomicBool::new(false),
            self_weak: StdRwLock::new(None),
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_webrtc_streamer_config_default() {
        let config = WebRtcStreamerConfig::default();
        assert_eq!(config.video_codec, VideoCodecType::H264);
        assert_eq!(config.resolution, Resolution::HD720);
        assert_eq!(config.bitrate_preset, BitratePreset::Balanced);
        assert_eq!(config.fps, 30);
        assert!(!config.audio_enabled);
    }

    #[tokio::test]
    async fn test_supported_codecs() {
        let streamer = WebRtcStreamer::new();
        let codecs = streamer.supported_video_codecs();
        assert!(codecs.contains(&VideoCodecType::H264));
    }

    #[test]
    fn stop_pipeline_requires_no_sessions_and_no_subscribers() {
        assert!(WebRtcStreamer::should_stop_pipeline(0, 0));
        assert!(!WebRtcStreamer::should_stop_pipeline(1, 0));
        assert!(!WebRtcStreamer::should_stop_pipeline(0, 1));
        assert!(!WebRtcStreamer::should_stop_pipeline(2, 3));
    }
}