//! Implement the default transport, which opens TCP connections using a

//! happy-eyeballs style parallel algorithm.

use std::{net::SocketAddr, sync::Arc, time::Duration};

use async_trait::async_trait;

use futures::{stream::FuturesUnordered, FutureExt, StreamExt, TryFutureExt};

use safelog::sensitive as sv;

use tor_error::bad_api_usage;

use tor_linkspec::{ChannelMethod, HasChanMethod, OwnedChanTarget};

use tor_rtcompat::{NetStreamProvider, Runtime};

use tracing::trace;

use crate::Error;

/// A default transport object that opens TCP connections for a

/// `ChannelMethod::Direct`.

///

/// It opens almost-simultaneous parallel TCP connections to each address, and

/// chooses the first one to succeed.

#[derive(Clone, Debug)]

pub(crate) struct DefaultTransport<R: Runtime> {

    /// The runtime that we use for connecting.

    runtime: R,

}

impl<R: Runtime> DefaultTransport<R> {

    /// Construct a new DefaultTransport

}

#[async_trait]

impl<R: Runtime> crate::transport::TransportImplHelper for DefaultTransport<R> {

    type Stream = <R as NetStreamProvider>::Stream;

    /// Implements the transport: makes a TCP connection (possibly

    /// tunneled over whatever protocol) if possible.

    async fn connect(

        &self,

        target: &OwnedChanTarget,

            #[allow(unreachable_patterns)]

            _ => {

            }

        };

}

/// Time to wait between starting parallel connections to the same relay.

static CONNECTION_DELAY: Duration = Duration::from_millis(150);

/// Connect to one of the addresses in `addrs` by running connections in parallel until one works.

///

/// This implements a basic version of RFC 8305 "happy eyeballs".

            }

            }

        }

    }

    // Ensure we don't continue trying to make connections.

#[cfg(test)]

mod test {

    // @@ begin test lint list maintained by maint/add_warning @@

    #![allow(clippy::bool_assert_comparison)]

    #![allow(clippy::clone_on_copy)]

    #![allow(clippy::dbg_macro)]

    #![allow(clippy::mixed_attributes_style)]

    #![allow(clippy::print_stderr)]

    #![allow(clippy::print_stdout)]

    #![allow(clippy::single_char_pattern)]

    #![allow(clippy::unwrap_used)]

    #![allow(clippy::unchecked_duration_subtraction)]

    #![allow(clippy::useless_vec)]

    #![allow(clippy::needless_pass_by_value)]

    //! <!-- @@ end test lint list maintained by maint/add_warning @@ -->

    use std::str::FromStr;

    use tor_rtcompat::{test_with_one_runtime, SleepProviderExt};

    use tor_rtmock::net::MockNetwork;

    use super::*;

    #[test]

    fn test_connect_one() {

        let client_addr = "192.0.1.16".parse().unwrap();

        // We'll put a "relay" at this address

        let addr1 = SocketAddr::from_str("192.0.2.17:443").unwrap();

        // We'll put nothing at this address, to generate errors.

        let addr2 = SocketAddr::from_str("192.0.3.18:443").unwrap();

        // Well put a black hole at this address, to generate timeouts.

        let addr3 = SocketAddr::from_str("192.0.4.19:443").unwrap();

        // We'll put a "relay" at this address too

        let addr4 = SocketAddr::from_str("192.0.9.9:443").unwrap();

        test_with_one_runtime!(|rt| async move {

            // Stub out the internet so that this connection can work.

            let network = MockNetwork::new();

            // Set up a client and server runtime with a given IP

            let client_rt = network

                .builder()

                .add_address(client_addr)

                .runtime(rt.clone());

            let server_rt = network

                .builder()

                .add_address(addr1.ip())

                .add_address(addr4.ip())

                .runtime(rt.clone());

            let _listener = server_rt.mock_net().listen(&addr1).await.unwrap();

            let _listener2 = server_rt.mock_net().listen(&addr4).await.unwrap();

            // TODO: Because this test doesn't mock time, there will actually be

            // delays as we wait for connections to this address to time out. It

            // would be good to use MockSleepProvider instead, once we figure

            // out how to make it both reliable and convenient.

            network.add_blackhole(addr3).unwrap();

            // No addresses? Can't succeed.

            let failure = connect_to_one(&client_rt, &[]).await;

            assert!(failure.is_err());

            // Connect to a set of addresses including addr1? That's a success.

            for addresses in [

                &[addr1][..],

                &[addr1, addr2][..],

                &[addr2, addr1][..],

                &[addr1, addr3][..],

                &[addr3, addr1][..],

                &[addr1, addr2, addr3][..],

                &[addr3, addr2, addr1][..],

            ] {

                let (_conn, addr) = connect_to_one(&client_rt, addresses).await.unwrap();

                assert_eq!(addr, addr1);

            }

            // Connect to a set of addresses including addr2 but not addr1?

            // That's an error of one kind or another.

            for addresses in [

                &[addr2][..],

                &[addr2, addr3][..],

                &[addr3, addr2][..],

                &[addr3][..],

            ] {

                let expect_timeout = addresses.contains(&addr3);

                let failure = rt

                    .timeout(

                        Duration::from_millis(300),

                        connect_to_one(&client_rt, addresses),

                    )

                    .await;

                if expect_timeout {

                    assert!(failure.is_err());

                } else {

                    assert!(failure.unwrap().is_err());

                }

            }

            // Connect to addr1 and addr4?  The first one should win.

            let (_conn, addr) = connect_to_one(&client_rt, &[addr1, addr4]).await.unwrap();

            assert_eq!(addr, addr1);

            let (_conn, addr) = connect_to_one(&client_rt, &[addr4, addr1]).await.unwrap();

            assert_eq!(addr, addr4);

        });

    }

}