use std::mem::replace;
use std::error::Error;
use futures::{Future, Poll, Async, sink, Stream};
use tokio_io::{AsyncRead, AsyncWrite};
use xmpp_parsers::iq::{Iq, IqType};
use xmpp_parsers::bind::Bind;
use try_from::TryFrom;

use xmpp_codec::Packet;
use xmpp_stream::XMPPStream;

const NS_XMPP_BIND: &str = "urn:ietf:params:xml:ns:xmpp-bind";
const BIND_REQ_ID: &str = "resource-bind";

pub enum ClientBind<S: AsyncWrite> {
    Unsupported(XMPPStream<S>),
    WaitSend(sink::Send<XMPPStream<S>>),
    WaitRecv(XMPPStream<S>),
    Invalid,
}

impl<S: AsyncWrite> ClientBind<S> {
    /// Consumes and returns the stream to express that you cannot use
    /// the stream for anything else until the resource binding
    /// req/resp are done.
    pub fn new(stream: XMPPStream<S>) -> Self {
        match stream.stream_features.get_child("bind", NS_XMPP_BIND) {
            None =>
                // No resource binding available,
                // return the (probably // usable) stream immediately
                ClientBind::Unsupported(stream),
            Some(_) => {
                let resource = stream.jid.resource.clone();
                let iq = Iq::from_set(Bind::new(resource))
                    .with_id(BIND_REQ_ID.to_string());
                let send = stream.send_stanza(iq);
                ClientBind::WaitSend(send)
            },
        }
    }
}

impl<S: AsyncRead + AsyncWrite> Future for ClientBind<S> {
    type Item = XMPPStream<S>;
    type Error = String;

    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
        let state = replace(self, ClientBind::Invalid);

        match state {
            ClientBind::Unsupported(stream) =>
                Ok(Async::Ready(stream)),
            ClientBind::WaitSend(mut send) => {
                match send.poll() {
                    Ok(Async::Ready(stream)) => {
                        replace(self, ClientBind::WaitRecv(stream));
                        self.poll()
                    },
                    Ok(Async::NotReady) => {
                        replace(self, ClientBind::WaitSend(send));
                        Ok(Async::NotReady)
                    },
                    Err(e) =>
                        Err(e.description().to_owned()),
                }
            },
            ClientBind::WaitRecv(mut stream) => {
                match stream.poll() {
                    Ok(Async::Ready(Some(Packet::Stanza(stanza)))) =>
                        match Iq::try_from(stanza) {
                            Ok(iq) => if iq.id == Some(BIND_REQ_ID.to_string()) {
                                match iq.payload {
                                    IqType::Result(payload) => {
                                        payload
                                            .and_then(|payload| Bind::try_from(payload).ok())
                                            .map(|bind| match bind {
                                                Bind::Jid(jid) => stream.jid = jid,
                                                _ => {}
                                            });
                                        Ok(Async::Ready(stream))
                                    },
                                    _ =>
                                        Err("resource bind response".to_owned()),
                                }
                            } else {
                                Ok(Async::NotReady)
                            },
                            _ => Ok(Async::NotReady),
                        },
                    Ok(Async::Ready(_)) => {
                        replace(self, ClientBind::WaitRecv(stream));
                        self.poll()
                    },
                    Ok(Async::NotReady) => {
                        replace(self, ClientBind::WaitRecv(stream));
                        Ok(Async::NotReady)
                    },
                    Err(e) =>
                        Err(e.description().to_owned()),
                }
            },
            ClientBind::Invalid =>
                unreachable!(),
        }
    }
}