use mio::*;
use mio::deprecated::{EventLoop, Handler};
use mio::udp::*;
use bytes::{Buf, MutBuf, RingBuf, SliceBuf};
use std::str;
use std::net::{SocketAddr, Ipv4Addr};
use localhost;

const LISTENER: Token = Token(0);
const SENDER: Token = Token(1);

pub struct UdpHandler {
    tx: UdpSocket,
    rx: UdpSocket,
    msg: &'static str,
    buf: SliceBuf<'static>,
    rx_buf: RingBuf
}

impl UdpHandler {
    fn new(tx: UdpSocket, rx: UdpSocket, msg: &'static str) -> UdpHandler {
        UdpHandler {
            tx: tx,
            rx: rx,
            msg: msg,
            buf: SliceBuf::wrap(msg.as_bytes()),
            rx_buf: RingBuf::new(1024)
        }
    }

    fn handle_read(&mut self, event_loop: &mut EventLoop<UdpHandler>, token: Token, _: Ready) {
        match token {
            LISTENER => {
                debug!("We are receiving a datagram now...");
                match unsafe { self.rx.recv_from(self.rx_buf.mut_bytes()) } {
                    Ok(Some((cnt, SocketAddr::V4(addr)))) => {
                        unsafe { MutBuf::advance(&mut self.rx_buf, cnt); }
                        assert_eq!(*addr.ip(), Ipv4Addr::new(127, 0, 0, 1));
                    }
                    res => panic!("unexpected result: {:?}", res),
                }
                assert!(str::from_utf8(self.rx_buf.bytes()).unwrap() == self.msg);
                event_loop.shutdown();
            },
            _ => ()
        }
    }

    fn handle_write(&mut self, _: &mut EventLoop<UdpHandler>, token: Token, _: Ready) {
        match token {
            SENDER => {
                let addr = self.rx.local_addr().unwrap();
                let cnt = self.tx.send_to(self.buf.bytes(), &addr)
                                 .unwrap().unwrap();
                self.buf.advance(cnt);
            },
            _ => ()
        }
    }
}

impl Handler for UdpHandler {
    type Timeout = usize;
    type Message = ();

    fn ready(&mut self, event_loop: &mut EventLoop<UdpHandler>, token: Token, events: Ready) {
        if events.is_readable() {
            self.handle_read(event_loop, token, events);
        }

        if events.is_writable() {
            self.handle_write(event_loop, token, events);
        }
    }
}

#[test]
pub fn test_multicast() {
    drop(::env_logger::init());
    debug!("Starting TEST_UDP_CONNECTIONLESS");
    let mut event_loop = EventLoop::new().unwrap();

    let addr = localhost();
    let any = "0.0.0.0:0".parse().unwrap();

    let tx = UdpSocket::bind(&any).unwrap();
    let rx = UdpSocket::bind(&addr).unwrap();

    info!("Joining group 227.1.1.100");
    let any = "0.0.0.0".parse().unwrap();
    rx.join_multicast_v4(&"227.1.1.100".parse().unwrap(), &any).unwrap();

    info!("Joining group 227.1.1.101");
    rx.join_multicast_v4(&"227.1.1.101".parse().unwrap(), &any).unwrap();

    info!("Registering SENDER");
    event_loop.register(&tx, SENDER, Ready::writable(), PollOpt::edge()).unwrap();

    info!("Registering LISTENER");
    event_loop.register(&rx, LISTENER, Ready::readable(), PollOpt::edge()).unwrap();

    info!("Starting event loop to test with...");
    event_loop.run(&mut UdpHandler::new(tx, rx, "hello world")).unwrap();
}