use std::net::{IpAddr, Ipv4Addr};

use futures::StreamExt;
use tarpc::server;
use tarpc::server::incoming::Incoming;
use tarpc::server::{Channel, Serve};
use tarpc::tokio_serde::formats::Bincode;

pub async fn start<Server, Req, Build>(name: &str, port: u16, build: Build)
where
    Server: Serve<Req> + Send + 'static + Clone,
    Build: Fn() -> Server,
    <Server as Serve<Req>>::Fut: Send,
    <Server as Serve<Req>>::Resp: serde::Serialize + Send + 'static,
    Req: Send + 'static,
    Req: for<'l> serde::Deserialize<'l>,
{
    let server_addr = (IpAddr::V4(Ipv4Addr::LOCALHOST), port);

    let mut listener = tarpc::serde_transport::tcp::listen(&server_addr, Bincode::default)
        .await
        .unwrap();
    tracing::info!("Starting {} rpc at {}", name, listener.local_addr());
    listener.config_mut().max_frame_length(usize::MAX);
    listener
        // Ignore accept errors.
        .filter_map(|r| futures::future::ready(r.ok()))
        .map(server::BaseChannel::with_defaults)
        // Limit channels to 8 per IP.
        .max_channels_per_key(8, |t| t.transport().peer_addr().unwrap().ip())
        .max_concurrent_requests_per_channel(20)
        // serve is generated by the service attribute. It takes as input any type implementing
        // the generated World trait.
        .map(|channel| channel.execute(build()))
        // Max 10 channels.
        .buffer_unordered(10)
        .for_each(|_| async {})
        .await;
    tracing::info!("RPC channel closed");
}