// Copyright 2017-2019 Parity Technologies (UK) Ltd.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

//! Implementation of the libp2p `Transport` trait for Websockets.

pub mod error;
pub mod framed;
pub mod tls;

use error::Error;
use framed::Connection;
use futures::{future::BoxFuture, prelude::*, stream::BoxStream, ready};
use libp2p_core::{
    ConnectedPoint,
    Transport,
    multiaddr::Multiaddr,
    transport::{map::{MapFuture, MapStream}, ListenerEvent, TransportError}
};
use rw_stream_sink::RwStreamSink;
use std::{io, pin::Pin, task::{Context, Poll}};

/// A Websocket transport.
#[derive(Debug, Clone)]
pub struct WsConfig<T> {
    transport: framed::WsConfig<T>
}

impl<T> WsConfig<T> {
    /// Create a new websocket transport based on the given transport.
    pub fn new(transport: T) -> Self {
        framed::WsConfig::new(transport).into()
    }

    /// Return the configured maximum number of redirects.
    pub fn max_redirects(&self) -> u8 {
        self.transport.max_redirects()
    }

    /// Set max. number of redirects to follow.
    pub fn set_max_redirects(&mut self, max: u8) -> &mut Self {
        self.transport.set_max_redirects(max);
        self
    }

    /// Get the max. frame data size we support.
    pub fn max_data_size(&self) -> usize {
        self.transport.max_data_size()
    }

    /// Set the max. frame data size we support.
    pub fn set_max_data_size(&mut self, size: usize) -> &mut Self {
        self.transport.set_max_data_size(size);
        self
    }

    /// Set the TLS configuration if TLS support is desired.
    pub fn set_tls_config(&mut self, c: tls::Config) -> &mut Self {
        self.transport.set_tls_config(c);
        self
    }

    /// Should the deflate extension (RFC 7692) be used if supported?
    pub fn use_deflate(&mut self, flag: bool) -> &mut Self {
        self.transport.use_deflate(flag);
        self
    }
}

impl<T> From<framed::WsConfig<T>> for WsConfig<T> {
    fn from(framed: framed::WsConfig<T>) -> Self {
        WsConfig {
            transport: framed
        }
    }
}

impl<T> Transport for WsConfig<T>
where
    T: Transport + Send + Clone + 'static,
    T::Error: Send + 'static,
    T::Dial: Send + 'static,
    T::Listener: Send + 'static,
    T::ListenerUpgrade: Send + 'static,
    T::Output: AsyncRead + AsyncWrite + Unpin + Send + 'static
{
    type Output = RwStreamSink<BytesConnection<T::Output>>;
    type Error = Error<T::Error>;
    type Listener = MapStream<InnerStream<T::Output, T::Error>, WrapperFn<T::Output>>;
    type ListenerUpgrade = MapFuture<InnerFuture<T::Output, T::Error>, WrapperFn<T::Output>>;
    type Dial = MapFuture<InnerFuture<T::Output, T::Error>, WrapperFn<T::Output>>;

    fn listen_on(self, addr: Multiaddr) -> Result<Self::Listener, TransportError<Self::Error>> {
        self.transport.map(wrap_connection as WrapperFn<T::Output>).listen_on(addr)
    }

    fn dial(self, addr: Multiaddr) -> Result<Self::Dial, TransportError<Self::Error>> {
        self.transport.map(wrap_connection as WrapperFn<T::Output>).dial(addr)
    }
}

/// Type alias corresponding to `framed::WsConfig::Listener`.
pub type InnerStream<T, E> = BoxStream<'static, Result<ListenerEvent<InnerFuture<T, E>, Error<E>>, Error<E>>>;

/// Type alias corresponding to `framed::WsConfig::Dial` and `framed::WsConfig::ListenerUpgrade`.
pub type InnerFuture<T, E> = BoxFuture<'static, Result<Connection<T>, Error<E>>>;

/// Function type that wraps a websocket connection (see. `wrap_connection`).
pub type WrapperFn<T> = fn(Connection<T>, ConnectedPoint) -> RwStreamSink<BytesConnection<T>>;

/// Wrap a websocket connection producing data frames into a `RwStreamSink`
/// implementing `AsyncRead` + `AsyncWrite`.
fn wrap_connection<T>(c: Connection<T>, _: ConnectedPoint) -> RwStreamSink<BytesConnection<T>>
where
    T: AsyncRead + AsyncWrite + Send + Unpin + 'static
{
    RwStreamSink::new(BytesConnection(c))
}

/// The websocket connection.
#[derive(Debug)]
pub struct BytesConnection<T>(Connection<T>);

impl<T> Stream for BytesConnection<T>
where
    T: AsyncRead + AsyncWrite + Send + Unpin + 'static
{
    type Item = io::Result<Vec<u8>>;

    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
        loop {
            if let Some(item) = ready!(self.0.try_poll_next_unpin(cx)?) {
                if item.is_data() {
                    return Poll::Ready(Some(Ok(item.into_bytes())))
                }
            } else {
                return Poll::Ready(None)
            }
        }
    }
}

impl<T> Sink<Vec<u8>> for BytesConnection<T>
where
    T: AsyncRead + AsyncWrite + Send + Unpin + 'static
{
    type Error = io::Error;

    fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
        Pin::new(&mut self.0).poll_ready(cx)
    }

    fn start_send(mut self: Pin<&mut Self>, item: Vec<u8>) -> io::Result<()> {
        Pin::new(&mut self.0).start_send(framed::OutgoingData::Binary(item))
    }

    fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
        Pin::new(&mut self.0).poll_flush(cx)
    }

    fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
        Pin::new(&mut self.0).poll_close(cx)
    }
}

// Tests //////////////////////////////////////////////////////////////////////////////////////////

#[cfg(test)]
mod tests {
    use libp2p_core::Multiaddr;
    use libp2p_tcp as tcp;
    use futures::prelude::*;
    use libp2p_core::{Transport, multiaddr::Protocol};
    use super::WsConfig;

    #[test]
    fn dialer_connects_to_listener_ipv4() {
        let a = "/ip4/127.0.0.1/tcp/0/ws".parse().unwrap();
        futures::executor::block_on(connect(a))
    }

    #[test]
    fn dialer_connects_to_listener_ipv6() {
        let a = "/ip6/::1/tcp/0/ws".parse().unwrap();
        futures::executor::block_on(connect(a))
    }

    async fn connect(listen_addr: Multiaddr) {
        let ws_config = WsConfig::new(tcp::TcpConfig::new());

        let mut listener = ws_config.clone()
            .listen_on(listen_addr)
            .expect("listener");

        let addr = listener.try_next().await
            .expect("some event")
            .expect("no error")
            .into_new_address()
            .expect("listen address");

        assert_eq!(Some(Protocol::Ws("/".into())), addr.iter().nth(2));
        assert_ne!(Some(Protocol::Tcp(0)), addr.iter().nth(1));

        let inbound = async move {
            let (conn, _addr) = listener.try_filter_map(|e| future::ready(Ok(e.into_upgrade())))
                .try_next()
                .await
                .unwrap()
                .unwrap();
            conn.await
        };

        let outbound = ws_config.dial(addr).unwrap();

        let (a, b) = futures::join!(inbound, outbound);
        a.and(b).unwrap();
    }
}