use super::*;
use rustls::Session;
use crate::common::IoSession;

/// A wrapper around an underlying raw stream which implements the TLS or SSL
/// protocol.
#[derive(Debug)]
pub struct TlsStream<IO> {
    pub(crate) io: IO,
    pub(crate) session: ServerSession,
    pub(crate) state: TlsState,
}

impl<IO> TlsStream<IO> {
    #[inline]
    pub fn get_ref(&self) -> (&IO, &ServerSession) {
        (&self.io, &self.session)
    }

    #[inline]
    pub fn get_mut(&mut self) -> (&mut IO, &mut ServerSession) {
        (&mut self.io, &mut self.session)
    }

    #[inline]
    pub fn into_inner(self) -> (IO, ServerSession) {
        (self.io, self.session)
    }
}

impl<IO> IoSession for TlsStream<IO> {
    type Io = IO;
    type Session = ServerSession;

    #[inline]
    fn skip_handshake(&self) -> bool {
        false
    }

    #[inline]
    fn get_mut(&mut self) -> (&mut TlsState, &mut Self::Io, &mut Self::Session) {
        (&mut self.state, &mut self.io, &mut self.session)
    }

    #[inline]
    fn into_io(self) -> Self::Io {
        self.io
    }
}

impl<IO> AsyncRead for TlsStream<IO>
where
    IO: AsyncRead + AsyncWrite + Unpin,
{
    #[cfg(feature = "unstable")]
    unsafe fn prepare_uninitialized_buffer(&self, _buf: &mut [std::mem::MaybeUninit<u8>]) -> bool {
        // TODO
        //
        // https://doc.rust-lang.org/nightly/std/io/trait.Read.html#method.initializer
        false
    }

    fn poll_read(self: Pin<&mut Self>, cx: &mut Context<'_>, buf: &mut [u8]) -> Poll<io::Result<usize>> {
        let this = self.get_mut();
        let mut stream = Stream::new(&mut this.io, &mut this.session)
            .set_eof(!this.state.readable());

        match &this.state {
            TlsState::Stream | TlsState::WriteShutdown => match stream.as_mut_pin().poll_read(cx, buf) {
                Poll::Ready(Ok(0)) => {
                    this.state.shutdown_read();
                    Poll::Ready(Ok(0))
                }
                Poll::Ready(Ok(n)) => Poll::Ready(Ok(n)),
                Poll::Ready(Err(ref err)) if err.kind() == io::ErrorKind::ConnectionAborted => {
                    this.state.shutdown_read();
                    if this.state.writeable() {
                        stream.session.send_close_notify();
                        this.state.shutdown_write();
                    }
                    Poll::Ready(Ok(0))
                }
                Poll::Ready(Err(e)) => Poll::Ready(Err(e)),
                Poll::Pending => Poll::Pending
            },
            TlsState::ReadShutdown | TlsState::FullyShutdown => Poll::Ready(Ok(0)),
            #[cfg(feature = "early-data")]
            s => unreachable!("server TLS can not hit this state: {:?}", s),
        }
    }
}

impl<IO> AsyncWrite for TlsStream<IO>
where
    IO: AsyncRead + AsyncWrite + Unpin,
{
    /// Note: that it does not guarantee the final data to be sent.
    /// To be cautious, you must manually call `flush`.
    fn poll_write(self: Pin<&mut Self>, cx: &mut Context<'_>, buf: &[u8]) -> Poll<io::Result<usize>> {
        let this = self.get_mut();
        let mut stream = Stream::new(&mut this.io, &mut this.session)
            .set_eof(!this.state.readable());
        stream.as_mut_pin().poll_write(cx, buf)
    }

    fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
        let this = self.get_mut();
        let mut stream = Stream::new(&mut this.io, &mut this.session)
            .set_eof(!this.state.readable());
        stream.as_mut_pin().poll_flush(cx)
    }

    fn poll_shutdown(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
        if self.state.writeable() {
            self.session.send_close_notify();
            self.state.shutdown_write();
        }

        let this = self.get_mut();
        let mut stream = Stream::new(&mut this.io, &mut this.session)
            .set_eof(!this.state.readable());
        stream.as_mut_pin().poll_shutdown(cx)
    }
}
