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use futures::{future, Future, Poll};
use hyper::client::connect::{Connect, Connected, Destination};
use socks::{Socks4Stream, Socks5Stream};
use std::{io, net::ToSocketAddrs};
use tokio::{net::TcpStream, reactor::Handle};

pub struct Connection(Box<Future<Item = (TcpStream, Connected), Error = io::Error> + Send>);

impl Connection {
    fn new<F>(f: F) -> Self
    where
        F: Future<Item = (TcpStream, Connected), Error = io::Error> + Send + 'static,
    {
        Connection(Box::new(f))
    }
}

impl Future for Connection {
    type Item = (TcpStream, Connected);
    type Error = io::Error;

    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
        self.0.poll()
    }
}

#[derive(Debug)]
pub enum Proxy<T: ToSocketAddrs> {
    Socks4 { addrs: T, user_id: String },
    Socks5 { addrs: T, auth: Option<Auth> },
}

#[derive(Debug)]
pub struct Auth {
    pub user: String,
    pub pass: String,
}

pub struct Connector<T: ToSocketAddrs>(Proxy<T>);

impl<T> Connector<T>
where
    T: ToSocketAddrs,
{
    pub fn new(proxy: Proxy<T>) -> Self {
        Connector(proxy)
    }
}

impl<T> Connect for Connector<T>
where
    T: ToSocketAddrs + Send + Sync,
{
    type Transport = TcpStream;
    type Error = io::Error;
    type Future = Connection;

    fn connect(&self, dst: Destination) -> Self::Future {
        let scheme = dst.scheme();
        let port = if let Some(p) = dst.port() {
            p
        } else if scheme == "http" {
            80
        } else if scheme == "https" {
            443
        } else {
            return Connection::new(future::err(io::Error::new(
                io::ErrorKind::InvalidInput,
                "missing port",
            )));
        };
        let target = (dst.host(), port);

        let fut = match self.0 {
            Proxy::Socks4 {
                ref addrs,
                ref user_id,
            } => {
                let res = Socks4Stream::connect(addrs, target, user_id.as_str())
                    .map(|stream| stream.into_inner());
                future::result(res)
            }
            Proxy::Socks5 {
                ref addrs,
                ref auth,
            } => {
                let res = match auth {
                    Some(auth) => {
                        Socks5Stream::connect_with_password(addrs, target, &auth.user, &auth.pass)
                    }
                    None => Socks5Stream::connect(addrs, target),
                };
                let res = res.map(|stream| stream.into_inner());
                future::result(res)
            }
        };
        let fut = fut
            .and_then(|stream| TcpStream::from_std(stream, &Handle::default()))
            .map(|stream| (stream, Connected::new().proxy(true)));

        Connection::new(fut)
    }
}