//! A simple example of hooking up stdin/stdout to a WebSocket stream.
//!
//! This example will connect to a server specified in the argument list and
//! then forward all data read on stdin to the server, printing out all data
//! received on stdout.
//!
//! Note that this is not currently optimized for performance, especially around
//! buffer management. Rather it's intended to show an example of working with a
//! client.
//!
//! You can use this example together with the `server` example.

use std::env;

use futures::{future, pin_mut, StreamExt};
use tokio::io::{AsyncReadExt, AsyncWriteExt};
use tokio_tungstenite::connect_async;
use tungstenite::protocol::Message;

#[tokio::main]
async fn main() {
  let connect_addr = env::args()
    .nth(1)
    .unwrap_or_else(|| panic!("this program requires at least one argument"));

  let url = url::Url::parse(&connect_addr).unwrap();

  let (stdin_tx, stdin_rx) = futures::channel::mpsc::unbounded();
  tokio::spawn(read_stdin(stdin_tx));

  let (ws_stream, _) = connect_async(url).await.expect("Failed to connect");
  println!("WebSocket handshake has been successfully completed");

  let (write, read) = ws_stream.split();

  let stdin_to_ws = stdin_rx.map(Ok).forward(write);
  let ws_to_stdout = {
    read.for_each(|message| {
      async {
        let data = message.unwrap().into_data();
        tokio::io::stdout().write_all(&data).await.unwrap();
      }
    })
  };

  pin_mut!(stdin_to_ws, ws_to_stdout);
  future::select(stdin_to_ws, ws_to_stdout).await;
}

// Our helper method which will read data from stdin and send it along the
// sender provided.
async fn read_stdin(tx: futures::channel::mpsc::UnboundedSender<Message>) {
  let mut stdin = tokio::io::stdin();
  loop {
    let mut buf = vec![0; 1024];
    let n = match stdin.read(&mut buf).await {
      Err(_) | Ok(0) => break,
      Ok(n) => n,
    };
    buf.truncate(n);
    tx.unbounded_send(Message::binary(buf)).unwrap();
  }
}