extern crate asyncio;
extern crate time;

use std::io;
use asyncio::*;
use asyncio::ip::*;
use asyncio::socket_base::*;

struct DaytimeUdp {
    soc: UdpSocket,
    buf: [u8; 128],
}

impl DaytimeUdp {
    fn on_start(daytime: Strand<Self>) {
        daytime.soc.set_option(ReuseAddr::new(true)).unwrap();

        daytime.soc.bind(&UdpEndpoint::new(IpAddrV4::any(), 13)).unwrap();

        daytime.soc.async_receive_from(&mut daytime.get().buf, 0, daytime.wrap(DaytimeUdp::on_receive));
    }

    fn on_receive(mut daytime: Strand<Self>, res: io::Result<(usize, UdpEndpoint)>) {
        if let Ok((_, ep)) = res {
            println!("receive from {}", ep);

            let buf = format!("{}\r\n", time::now().ctime());
            let len = buf.len();
            daytime.buf[..len].copy_from_slice(buf.as_bytes());
            daytime.soc.async_send_to(&daytime.buf[..len], 0, ep, daytime.wrap(Self::on_send));
        }
    }

    fn on_send(daytime: Strand<Self>, res: io::Result<usize>) {
        if let Ok(_) = res {
            daytime.soc.async_receive_from( &mut daytime.get().buf, 0, daytime.wrap(Self::on_receive));
        }
    }
}

fn main() {
    let ctx = &IoContext::new().unwrap();

    let daytime = IoContext::strand(ctx, DaytimeUdp {
        soc: UdpSocket::new(ctx, Udp::v4()).unwrap(),
        buf: [0; 128],
    });
    daytime.dispatch(DaytimeUdp::on_start);

    ctx.run();
}