use std::io::{Read,Write};
use std::net::{TcpListener,TcpStream};
use std::thread;

fn read_str (stream: &mut TcpStream) -> String {
  let mut buf = vec![0u8; 256];
  let x = stream.read(&mut buf).unwrap();

  println!("read {} bytes", x);
  if buf[x-2] == b'\r' && buf[x-1] == b'\n' {
    // ...
  } else {
    panic!("single read not CRLF terminated: {:?}", buf);
  }

  let str = String::from_utf8_lossy(&buf[0..x-2]);
  return str.into_owned();
}

fn say_hello (stream: TcpStream) {
  let mut stream = stream;
  stream.write(b"[GWIZ] v15.11.17 - defense systems online\r\n").unwrap();

  for _ in 0..3 {
    stream.write(b"username: ").unwrap();
    let uname = read_str(&mut stream);

    stream.write(b"password: ").unwrap();
    let pword = read_str(&mut stream);
    println!("login attempt <{}> / <{}>", uname, pword);

    if uname == "rjbs" && pword == "secret" { return spill_guts(stream) }

    stream.write(b"invalid login\r\n").unwrap();
  }

  stream.write(b"too many attempts\r\n").unwrap();
}

fn spill_guts (stream: TcpStream) {
  let mut stream = stream;
  stream.write(b"launch codes: 123456\r\n").unwrap();
}

fn main() {
  let listen   = "127.0.0.1:9999";
  let listener = TcpListener::bind( &listen )
                 .ok()
                 .expect( &format!("can't bind to {}!", listen) );

  println!("listening started, ready to accept");

  for stream in listener.incoming() {
    thread::spawn(move || say_hello(stream.unwrap()) );
  }
}