// Copyright 2020 Parity Technologies (UK) Ltd.
//
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//! Integration tests for the `RequestResponse` network behaviour.

use async_trait::async_trait;
use libp2p_core::{
    Multiaddr,
    PeerId,
    identity,
    muxing::StreamMuxerBox,
    transport::{Transport, boxed::Boxed},
    upgrade::{self, read_one, write_one}
};
use libp2p_noise::{NoiseConfig, X25519Spec, Keypair};
use libp2p_request_response::*;
use libp2p_swarm::Swarm;
use libp2p_tcp::TcpConfig;
use futures::{prelude::*, channel::mpsc};
use rand::{self, Rng};
use std::{io, iter};

/// Exercises a simple ping protocol.
#[test]
fn ping_protocol() {
    let num_pings: u8 = rand::thread_rng().gen_range(1, 100);

    let ping = Ping("ping".to_string().into_bytes());
    let pong = Pong("pong".to_string().into_bytes());

    let protocols = iter::once((PingProtocol(), ProtocolSupport::Full));
    let cfg = RequestResponseConfig::default();

    let (peer1_id, trans) = mk_transport();
    let ping_proto1 = RequestResponse::new(PingCodec(), protocols.clone(), cfg.clone());
    let mut swarm1 = Swarm::new(trans, ping_proto1, peer1_id.clone());

    let (peer2_id, trans) = mk_transport();
    let ping_proto2 = RequestResponse::new(PingCodec(), protocols, cfg);
    let mut swarm2 = Swarm::new(trans, ping_proto2, peer2_id.clone());

    let (mut tx, mut rx) = mpsc::channel::<Multiaddr>(1);

    let addr = "/ip4/127.0.0.1/tcp/0".parse().unwrap();
    Swarm::listen_on(&mut swarm1, addr).unwrap();

    let expected_ping = ping.clone();
    let expected_pong = pong.clone();

    let peer1 = async move {
        while let Some(_) = swarm1.next().now_or_never() {}

        let l = Swarm::listeners(&swarm1).next().unwrap();
        tx.send(l.clone()).await.unwrap();

        loop {
            match swarm1.next().await {
                RequestResponseEvent::Message {
                    peer,
                    message: RequestResponseMessage::Request { request, channel }
                } => {
                    assert_eq!(&request, &expected_ping);
                    assert_eq!(&peer, &peer2_id);
                    swarm1.send_response(channel, pong.clone());
                },
                e => panic!("Peer1: Unexpected event: {:?}", e)
            }
        }
    };

    let peer2 = async move {
        let mut count = 0;
        let addr = rx.next().await.unwrap();
        swarm2.add_address(&peer1_id, addr.clone());
        let mut req_id = swarm2.send_request(&peer1_id, ping.clone());

        loop {
            match swarm2.next().await {
                RequestResponseEvent::Message {
                    peer,
                    message: RequestResponseMessage::Response { request_id, response }
                } => {
                    count += 1;
                    assert_eq!(&response, &expected_pong);
                    assert_eq!(&peer, &peer1_id);
                    assert_eq!(req_id, request_id);
                    if count >= num_pings {
                        return
                    } else {
                        req_id = swarm2.send_request(&peer1_id, ping.clone());
                    }
                },
                e => panic!("Peer2: Unexpected event: {:?}", e)
            }
        }
    };

    async_std::task::spawn(Box::pin(peer1));
    let () = async_std::task::block_on(peer2);
}

fn mk_transport() -> (PeerId, Boxed<(PeerId, StreamMuxerBox), io::Error>) {
    let id_keys = identity::Keypair::generate_ed25519();
    let peer_id = id_keys.public().into_peer_id();
    let noise_keys = Keypair::<X25519Spec>::new().into_authentic(&id_keys).unwrap();
    let transport = TcpConfig::new()
        .nodelay(true)
        .upgrade(upgrade::Version::V1)
        .authenticate(NoiseConfig::xx(noise_keys).into_authenticated())
        .multiplex(libp2p_yamux::Config::default())
        .map(|(peer, muxer), _| (peer, StreamMuxerBox::new(muxer)))
        .map_err(|err| io::Error::new(io::ErrorKind::Other, err))
        .boxed();
    (peer_id, transport)
}

// Simple Ping-Pong Protocol

#[derive(Debug, Clone)]
struct PingProtocol();
#[derive(Clone)]
struct PingCodec();
#[derive(Debug, Clone, PartialEq, Eq)]
struct Ping(Vec<u8>);
#[derive(Debug, Clone, PartialEq, Eq)]
struct Pong(Vec<u8>);

impl ProtocolName for PingProtocol {
    fn protocol_name(&self) -> &[u8] {
        "/ping/1".as_bytes()
    }
}

#[async_trait]
impl RequestResponseCodec for PingCodec {
    type Protocol = PingProtocol;
    type Request = Ping;
    type Response = Pong;

    async fn read_request<T>(&mut self, _: &PingProtocol, io: &mut T)
        -> io::Result<Self::Request>
    where
        T: AsyncRead + Unpin + Send
    {
        read_one(io, 1024)
            .map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e))
            .map_ok(Ping)
            .await
    }

    async fn read_response<T>(&mut self, _: &PingProtocol, io: &mut T)
        -> io::Result<Self::Response>
    where
        T: AsyncRead + Unpin + Send
    {
        read_one(io, 1024)
            .map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e))
            .map_ok(Pong)
            .await
    }

    async fn write_request<T>(&mut self, _: &PingProtocol, io: &mut T, Ping(data): Ping)
        -> io::Result<()>
    where
        T: AsyncWrite + Unpin + Send
    {
        write_one(io, data).await
    }

    async fn write_response<T>(&mut self, _: &PingProtocol, io: &mut T, Pong(data): Pong)
        -> io::Result<()>
    where
        T: AsyncWrite + Unpin + Send
    {
        write_one(io, data).await
    }
}

