use navka_common::navka::{relay_server::{Relay, RelayServer}, HidReport};
use tokio::{fs::OpenOptions, io::AsyncWriteExt, sync::mpsc};
use tokio_stream::wrappers::ReceiverStream;
use tonic::{transport::Server, Request, Response, Status};

const HID_DEV: &str = "/dev/hidg0";

#[derive(Default)]
struct RelaySvc;

#[tonic::async_trait]
impl Relay for RelaySvc {
    type StreamStream = ReceiverStream<Result<HidReport, Status>>;

    async fn stream(
        &self,
        request: Request<tonic::Streaming<HidReport>>,
    ) -> Result<Response<Self::StreamStream>, Status> {
        let mut inbound = request.into_inner();
        let (tx, rx) = mpsc::channel(8);

        // writer task: client → hidg0
        tokio::spawn(async move {
            let mut hid = OpenOptions::new().write(true).open(HID_DEV).await.unwrap();
            while let Some(Ok(report)) = inbound.message().await {
                hid.write_all(&report.data).await.unwrap();
            }
        });

        // nothing to send back yet
        Ok(Response::new(ReceiverStream::new(rx)))
    }
}

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    let addr = "0.0.0.0:4000".parse()?;
    Server::builder()
        .add_service(RelayServer::new(RelaySvc::default()))
        .serve(addr)
        .await?;
    Ok(())
}