use std::marker::PhantomData;

use actix_service::{NewService, Service};
use futures::{future::ok, future::FutureResult, Async, Future, Poll};
use openssl::ssl::{HandshakeError, SslAcceptor};
use tokio_io::{AsyncRead, AsyncWrite};
use tokio_openssl::{AcceptAsync, SslAcceptorExt, SslStream};

use crate::counter::{Counter, CounterGuard};
use crate::ssl::MAX_CONN_COUNTER;
use crate::{Io, Protocol, ServerConfig};

/// Support `SSL` connections via openssl package
///
/// `ssl` feature enables `OpensslAcceptor` type
pub struct OpensslAcceptor<T: AsyncRead + AsyncWrite, P = ()> {
    acceptor: SslAcceptor,
    io: PhantomData<(T, P)>,
}

impl<T: AsyncRead + AsyncWrite, P> OpensslAcceptor<T, P> {
    /// Create default `OpensslAcceptor`
    pub fn new(acceptor: SslAcceptor) -> Self {
        OpensslAcceptor {
            acceptor,
            io: PhantomData,
        }
    }
}

impl<T: AsyncRead + AsyncWrite, P> Clone for OpensslAcceptor<T, P> {
    fn clone(&self) -> Self {
        Self {
            acceptor: self.acceptor.clone(),
            io: PhantomData,
        }
    }
}

impl<T: AsyncRead + AsyncWrite, P> NewService<ServerConfig> for OpensslAcceptor<T, P> {
    type Request = Io<T, P>;
    type Response = Io<SslStream<T>, P>;
    type Error = HandshakeError<T>;
    type Service = OpensslAcceptorService<T, P>;
    type InitError = ();
    type Future = FutureResult<Self::Service, Self::InitError>;

    fn new_service(&self, cfg: &ServerConfig) -> Self::Future {
        cfg.set_secure();

        MAX_CONN_COUNTER.with(|conns| {
            ok(OpensslAcceptorService {
                acceptor: self.acceptor.clone(),
                conns: conns.clone(),
                io: PhantomData,
            })
        })
    }
}

pub struct OpensslAcceptorService<T, P> {
    acceptor: SslAcceptor,
    conns: Counter,
    io: PhantomData<(T, P)>,
}

impl<T: AsyncRead + AsyncWrite, P> Service for OpensslAcceptorService<T, P> {
    type Request = Io<T, P>;
    type Response = Io<SslStream<T>, P>;
    type Error = HandshakeError<T>;
    type Future = OpensslAcceptorServiceFut<T, P>;

    fn poll_ready(&mut self) -> Poll<(), Self::Error> {
        if self.conns.available() {
            Ok(Async::Ready(()))
        } else {
            Ok(Async::NotReady)
        }
    }

    fn call(&mut self, req: Self::Request) -> Self::Future {
        let (io, params, _) = req.into_parts();
        OpensslAcceptorServiceFut {
            _guard: self.conns.get(),
            fut: SslAcceptorExt::accept_async(&self.acceptor, io),
            params: Some(params),
        }
    }
}

pub struct OpensslAcceptorServiceFut<T, P>
where
    T: AsyncRead + AsyncWrite,
{
    fut: AcceptAsync<T>,
    params: Option<P>,
    _guard: CounterGuard,
}

impl<T: AsyncRead + AsyncWrite, P> Future for OpensslAcceptorServiceFut<T, P> {
    type Item = Io<SslStream<T>, P>;
    type Error = HandshakeError<T>;

    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
        let io = futures::try_ready!(self.fut.poll());
        let proto = if let Some(protos) = io.get_ref().ssl().selected_alpn_protocol() {
            const H2: &[u8] = b"\x02h2";
            const HTTP10: &[u8] = b"\x08http/1.0";
            const HTTP11: &[u8] = b"\x08http/1.1";

            if protos.windows(3).any(|window| window == H2) {
                Protocol::Http2
            } else if protos.windows(9).any(|window| window == HTTP11) {
                Protocol::Http11
            } else if protos.windows(9).any(|window| window == HTTP10) {
                Protocol::Http10
            } else {
                Protocol::Unknown
            }
        } else {
            Protocol::Unknown
        };
        Ok(Async::Ready(Io::from_parts(
            io,
            self.params.take().unwrap(),
            proto,
        )))
    }
}