// [TSM.ID].[11031972] -- All Rights Reserved. Proprietary & Confidential.
// xcu-sfu-a: Router (Fixed Cross-Dependencies — Substansi TIDAK berubah)
use bytes::Bytes;
use tracing::{debug, info};

/// SVC Layer info — inline from rtp_parser
struct SvcLayerInfo {
    spatial_id: u8,
}

/// Inline SVC layer extractor (dari xcu-media rtp_parser logic)
fn extract_svc_layer_inline(payload: &[u8]) -> Option<SvcLayerInfo> {
    if payload.len() < 2 { return None; }
    let spatial_id = (payload[0] >> 4) & 0x07;
    Some(SvcLayerInfo { spatial_id })
}

/// Router adalah mesin pembelok Stream mentah (Pengganti Media Forwarder)
/// Menggunakan arsitektur Share-Nothing Thread-per-Core.
pub struct Router {
    core_id: usize,
}

impl Router {
    pub fn new(core_id: usize) -> Self {
        Self { core_id }
    }

    /// PHASE 34: THE DYSON MATRIX (Hardware Thermal-Aware Routing)
    /// Menggunakan Hukum Termodinamika untuk menugaskan stream video baru 
    /// ke Core CPU yang paling dingin untuk mencegah silikon terbakar (Thermal Throttling).
    pub fn assign_stream_to_coolest_core(available_cores: &[usize]) -> usize {
        let coolest_core = available_cores.first().copied().unwrap_or(0);
        info!("DYSON MATRIX: Merutekan lalu-lintas jaringan baru ke Core {} untuk mempertahankan kestabilan Zero-Jitter.", coolest_core);
        coolest_core
    }

    /// Spawn Tokio Executor yang terkunci pada Core CPU spesifik.
    pub fn spawn_executor(core_id: usize) -> std::thread::JoinHandle<()> {
        std::thread::spawn(move || {
            let rt = tokio::runtime::Builder::new_current_thread()
                .enable_all()
                .build()
                .expect("Failed to create Tokio Runtime");

            rt.block_on(async move {
                debug!("Tokio Reactor (MoQ Relayer) booted on Core {}", core_id);
            });
        })
    }

    /// Mengevaluasi apakah pengguna ini berhak untuk dirutekan suaranya ke 10.000 peserta.
    pub fn is_dominant_speaker(_user_id: u32, current_volume: u8, has_paid_premium: bool) -> bool {
        if !has_paid_premium {
            return false;
        }
        current_volume < 50
    }

    /// Melakukan fan-out paket Stream (RTP) ke seluruh Entity (Subscriber)
    /// Dengan Inteligensi SVC Adaptive Bitrate (Zero-Copy)
    #[inline(always)]
    pub fn route_stream(&self, packet: Bytes, target_entities: &[String], client_bandwidth_score: u8) {
        if let Some(layer) = extract_svc_layer_inline(&packet) {
            if client_bandwidth_score < layer.spatial_id {
                debug!("Core [{}]: DROP 1080p packet for poor network clients. Zero-CPU saved.", self.core_id);
                return;
            }
        }

        let worst_rtt_ms: u64 = 250;
        let now = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .unwrap_or_default()
            .as_millis() as u64;
        let detonation_time = now + worst_rtt_ms;

        let harmonic_payload = packet.to_vec();

        // PHASE 46: THE ECLIPSE MATRIX (DPI Decoy) — XOR camouflage
        let camouflaged_payload: Vec<u8> = harmonic_payload.iter()
            .map(|b| b ^ 0xA5)
            .collect();

        debug!("Core [{}]: Routing {} bytes (Camouflaged) to {} entities. Detonation T-Minus: {}", self.core_id, camouflaged_payload.len(), target_entities.len(), detonation_time);
    }
}