//! Components in XMPP are services/gateways that are logged into an
//! XMPP server under a JID consisting of just a domain name. They are
//! allowed to use any user and resource identifiers in their stanzas.
use futures::{done, Async, AsyncSink, Future, Poll, Sink, StartSend, Stream};
use std::mem::replace;
use std::str::FromStr;
use tokio::net::TcpStream;
use tokio_io::{AsyncRead, AsyncWrite};
use xmpp_parsers::{Element, Jid, JidParseError};

use super::event::Event;
use super::happy_eyeballs::Connecter;
use super::xmpp_codec::Packet;
use super::xmpp_stream;
use super::Error;

mod auth;
use self::auth::ComponentAuth;

/// Component connection to an XMPP server
pub struct Component {
    /// The component's Jabber-Id
    pub jid: Jid,
    state: ComponentState,
}

type XMPPStream = xmpp_stream::XMPPStream<TcpStream>;
const NS_JABBER_COMPONENT_ACCEPT: &str = "jabber:component:accept";

enum ComponentState {
    Invalid,
    Disconnected,
    Connecting(Box<dyn Future<Item = XMPPStream, Error = Error>>),
    Connected(XMPPStream),
}

impl Component {
    /// Start a new XMPP component
    ///
    /// Start polling the returned instance so that it will connect
    /// and yield events.
    pub fn new(jid: &str, password: &str, server: &str, port: u16) -> Result<Self, JidParseError> {
        let jid = Jid::from_str(jid)?;
        let password = password.to_owned();
        let connect = Self::make_connect(jid.clone(), password, server, port);
        Ok(Component {
            jid,
            state: ComponentState::Connecting(Box::new(connect)),
        })
    }

    fn make_connect(
        jid: Jid,
        password: String,
        server: &str,
        port: u16,
    ) -> impl Future<Item = XMPPStream, Error = Error> {
        let jid1 = jid.clone();
        let password = password;
        done(Connecter::from_lookup(server, None, port))
            .flatten()
            .and_then(move |tcp_stream| {
                xmpp_stream::XMPPStream::start(
                    tcp_stream,
                    jid1,
                    NS_JABBER_COMPONENT_ACCEPT.to_owned(),
                )
            })
            .and_then(move |xmpp_stream| Self::auth(xmpp_stream, password).expect("auth"))
    }

    fn auth<S: AsyncRead + AsyncWrite>(
        stream: xmpp_stream::XMPPStream<S>,
        password: String,
    ) -> Result<ComponentAuth<S>, Error> {
        ComponentAuth::new(stream, password)
    }
}

impl Stream for Component {
    type Item = Event;
    type Error = Error;

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

        match state {
            ComponentState::Invalid => Err(Error::InvalidState),
            ComponentState::Disconnected => Ok(Async::Ready(None)),
            ComponentState::Connecting(mut connect) => match connect.poll() {
                Ok(Async::Ready(stream)) => {
                    self.state = ComponentState::Connected(stream);
                    Ok(Async::Ready(Some(Event::Online(self.jid.clone()))))
                }
                Ok(Async::NotReady) => {
                    self.state = ComponentState::Connecting(connect);
                    Ok(Async::NotReady)
                }
                Err(e) => Err(e),
            },
            ComponentState::Connected(mut stream) => {
                // Poll sink
                match stream.poll_complete() {
                    Ok(Async::NotReady) => (),
                    Ok(Async::Ready(())) => (),
                    Err(e) => return Err(e)?,
                };

                // Poll stream
                match stream.poll() {
                    Ok(Async::NotReady) => {
                        self.state = ComponentState::Connected(stream);
                        Ok(Async::NotReady)
                    }
                    Ok(Async::Ready(None)) => {
                        // EOF
                        self.state = ComponentState::Disconnected;
                        Ok(Async::Ready(Some(Event::Disconnected)))
                    }
                    Ok(Async::Ready(Some(Packet::Stanza(stanza)))) => {
                        self.state = ComponentState::Connected(stream);
                        Ok(Async::Ready(Some(Event::Stanza(stanza))))
                    }
                    Ok(Async::Ready(_)) => {
                        self.state = ComponentState::Connected(stream);
                        Ok(Async::NotReady)
                    }
                    Err(e) => Err(e)?,
                }
            }
        }
    }
}

impl Sink for Component {
    type SinkItem = Element;
    type SinkError = Error;

    fn start_send(&mut self, item: Self::SinkItem) -> StartSend<Self::SinkItem, Self::SinkError> {
        match self.state {
            ComponentState::Connected(ref mut stream) => match stream
                .start_send(Packet::Stanza(item))
            {
                Ok(AsyncSink::NotReady(Packet::Stanza(stanza))) => Ok(AsyncSink::NotReady(stanza)),
                Ok(AsyncSink::NotReady(_)) => {
                    panic!("Component.start_send with stanza but got something else back")
                }
                Ok(AsyncSink::Ready) => Ok(AsyncSink::Ready),
                Err(e) => Err(e)?,
            },
            _ => Ok(AsyncSink::NotReady(item)),
        }
    }

    fn poll_complete(&mut self) -> Poll<(), Self::SinkError> {
        match &mut self.state {
            &mut ComponentState::Connected(ref mut stream) => {
                stream.poll_complete().map_err(|e| e.into())
            }
            _ => Ok(Async::Ready(())),
        }
    }
}