use std::fmt::Debug;
use std::marker::PhantomData;
use std::{io, net};

use actix_codec::{AsyncRead, AsyncWrite, Framed};
use actix_server_config::{Io, ServerConfig as SrvConfig};
use actix_service::{IntoNewService, NewService, Service};
use actix_utils::cloneable::CloneableService;
use bytes::Bytes;
use futures::future::{ok, FutureResult};
use futures::{try_ready, Async, Future, IntoFuture, Poll, Stream};
use h2::server::{self, Connection, Handshake};
use h2::RecvStream;
use log::error;

use crate::body::MessageBody;
use crate::config::{KeepAlive, ServiceConfig};
use crate::error::{DispatchError, Error, ParseError, ResponseError};
use crate::payload::Payload;
use crate::request::Request;
use crate::response::Response;

use super::dispatcher::Dispatcher;

/// `NewService` implementation for HTTP2 transport
pub struct H2Service<T, P, S, B> {
    srv: S,
    cfg: ServiceConfig,
    _t: PhantomData<(T, P, B)>,
}

impl<T, P, S, B> H2Service<T, P, S, B>
where
    S: NewService<SrvConfig, Request = Request>,
    S::Error: Debug,
    S::Response: Into<Response<B>>,
    <S::Service as Service>::Future: 'static,
    B: MessageBody + 'static,
{
    /// Create new `HttpService` instance.
    pub fn new<F: IntoNewService<S, SrvConfig>>(service: F) -> Self {
        let cfg = ServiceConfig::new(KeepAlive::Timeout(5), 5000, 0);

        H2Service {
            cfg,
            srv: service.into_new_service(),
            _t: PhantomData,
        }
    }

    /// Create new `HttpService` instance with config.
    pub fn with_config<F: IntoNewService<S, SrvConfig>>(
        cfg: ServiceConfig,
        service: F,
    ) -> Self {
        H2Service {
            cfg,
            srv: service.into_new_service(),
            _t: PhantomData,
        }
    }
}

impl<T, P, S, B> NewService<SrvConfig> for H2Service<T, P, S, B>
where
    T: AsyncRead + AsyncWrite,
    S: NewService<SrvConfig, Request = Request>,
    S::Error: Debug,
    S::Response: Into<Response<B>>,
    <S::Service as Service>::Future: 'static,
    B: MessageBody + 'static,
{
    type Request = Io<T, P>;
    type Response = ();
    type Error = DispatchError;
    type InitError = S::InitError;
    type Service = H2ServiceHandler<T, P, S::Service, B>;
    type Future = H2ServiceResponse<T, P, S, B>;

    fn new_service(&self, cfg: &SrvConfig) -> Self::Future {
        H2ServiceResponse {
            fut: self.srv.new_service(cfg).into_future(),
            cfg: Some(self.cfg.clone()),
            _t: PhantomData,
        }
    }
}

#[doc(hidden)]
pub struct H2ServiceResponse<T, P, S: NewService<SrvConfig, Request = Request>, B> {
    fut: <S::Future as IntoFuture>::Future,
    cfg: Option<ServiceConfig>,
    _t: PhantomData<(T, P, B)>,
}

impl<T, P, S, B> Future for H2ServiceResponse<T, P, S, B>
where
    T: AsyncRead + AsyncWrite,
    S: NewService<SrvConfig, Request = Request>,
    S::Error: Debug,
    S::Response: Into<Response<B>>,
    <S::Service as Service>::Future: 'static,
    B: MessageBody + 'static,
{
    type Item = H2ServiceHandler<T, P, S::Service, B>;
    type Error = S::InitError;

    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
        let service = try_ready!(self.fut.poll());
        Ok(Async::Ready(H2ServiceHandler::new(
            self.cfg.take().unwrap(),
            service,
        )))
    }
}

/// `Service` implementation for http/2 transport
pub struct H2ServiceHandler<T, P, S, B> {
    srv: CloneableService<S>,
    cfg: ServiceConfig,
    _t: PhantomData<(T, P, B)>,
}

impl<T, P, S, B> H2ServiceHandler<T, P, S, B>
where
    S: Service<Request = Request>,
    S::Error: Debug,
    S::Future: 'static,
    S::Response: Into<Response<B>>,
    B: MessageBody + 'static,
{
    fn new(cfg: ServiceConfig, srv: S) -> H2ServiceHandler<T, P, S, B> {
        H2ServiceHandler {
            cfg,
            srv: CloneableService::new(srv),
            _t: PhantomData,
        }
    }
}

impl<T, P, S, B> Service for H2ServiceHandler<T, P, S, B>
where
    T: AsyncRead + AsyncWrite,
    S: Service<Request = Request>,
    S::Error: Debug,
    S::Future: 'static,
    S::Response: Into<Response<B>>,
    B: MessageBody + 'static,
{
    type Request = Io<T, P>;
    type Response = ();
    type Error = DispatchError;
    type Future = H2ServiceHandlerResponse<T, S, B>;

    fn poll_ready(&mut self) -> Poll<(), Self::Error> {
        self.srv.poll_ready().map_err(|e| {
            error!("Service readiness error: {:?}", e);
            DispatchError::Service
        })
    }

    fn call(&mut self, req: Self::Request) -> Self::Future {
        H2ServiceHandlerResponse {
            state: State::Handshake(
                Some(self.srv.clone()),
                Some(self.cfg.clone()),
                server::handshake(req.into_parts().0),
            ),
        }
    }
}

enum State<T: AsyncRead + AsyncWrite, S: Service<Request = Request>, B: MessageBody>
where
    S::Future: 'static,
{
    Incoming(Dispatcher<T, S, B>),
    Handshake(
        Option<CloneableService<S>>,
        Option<ServiceConfig>,
        Handshake<T, Bytes>,
    ),
}

pub struct H2ServiceHandlerResponse<T, S, B>
where
    T: AsyncRead + AsyncWrite,
    S: Service<Request = Request>,
    S::Error: Debug,
    S::Future: 'static,
    S::Response: Into<Response<B>>,
    B: MessageBody + 'static,
{
    state: State<T, S, B>,
}

impl<T, S, B> Future for H2ServiceHandlerResponse<T, S, B>
where
    T: AsyncRead + AsyncWrite,
    S: Service<Request = Request>,
    S::Error: Debug,
    S::Future: 'static,
    S::Response: Into<Response<B>>,
    B: MessageBody,
{
    type Item = ();
    type Error = DispatchError;

    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
        match self.state {
            State::Incoming(ref mut disp) => disp.poll(),
            State::Handshake(ref mut srv, ref mut config, ref mut handshake) => {
                match handshake.poll() {
                    Ok(Async::Ready(conn)) => {
                        self.state = State::Incoming(Dispatcher::new(
                            srv.take().unwrap(),
                            conn,
                            config.take().unwrap(),
                            None,
                        ));
                        self.poll()
                    }
                    Ok(Async::NotReady) => Ok(Async::NotReady),
                    Err(err) => {
                        trace!("H2 handshake error: {}", err);
                        Err(err.into())
                    }
                }
            }
        }
    }
}