use std::{io, net, mem};
use std::rc::Rc;
use std::collections::VecDeque;

use actix::dev::*;
use futures::{Future, Poll, Async};
use tokio_core::net::{TcpListener, TcpStream};

use task::{Task, RequestInfo};
use reader::Reader;
use router::{Router, RoutingMap};

/// An HTTP Server
pub struct HttpServer {
    router: Rc<Router>,
}

impl Actor for HttpServer {
    type Context = Context<Self>;
}

impl HttpServer {
    /// Create new http server with specified `RoutingMap`
    pub fn new(routes: RoutingMap) -> Self {
        HttpServer {router: Rc::new(routes.into_router())}
    }

    /// Start listening for incomming connections.
    pub fn serve<Addr>(self, addr: &net::SocketAddr) -> io::Result<Addr>
        where Self: ActorAddress<Self, Addr>
    {
        let tcp = TcpListener::bind(addr, Arbiter::handle())?;

        Ok(HttpServer::create(move |ctx| {
            ctx.add_stream(tcp.incoming());
            self
        }))
    }
}

impl ResponseType<(TcpStream, net::SocketAddr)> for HttpServer {
    type Item = ();
    type Error = ();
}

impl StreamHandler<(TcpStream, net::SocketAddr), io::Error> for HttpServer {}

impl Handler<(TcpStream, net::SocketAddr), io::Error> for HttpServer {

    fn handle(&mut self, msg: (TcpStream, net::SocketAddr), _: &mut Context<Self>)
              -> Response<Self, (TcpStream, net::SocketAddr)>
    {
        Arbiter::handle().spawn(
            HttpChannel{router: Rc::clone(&self.router),
                        addr: msg.1,
                        stream: msg.0,
                        reader: Reader::new(),
                        error: false,
                        items: VecDeque::new(),
                        inactive: Vec::new(),
            });
        Self::empty()
    }
}


struct Entry {
    task: Task,
    req: RequestInfo,
    eof: bool,
    error: bool,
    finished: bool,
}

pub struct HttpChannel {
    router: Rc<Router>,
    #[allow(dead_code)]
    addr: net::SocketAddr,
    stream: TcpStream,
    reader: Reader,
    error: bool,
    items: VecDeque<Entry>,
    inactive: Vec<Entry>,
}

impl Actor for HttpChannel {
    type Context = Context<Self>;
}

impl Future for HttpChannel {
    type Item = ();
    type Error = ();

    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
        loop {
            // check in-flight messages
            let mut idx = 0;
            while idx < self.items.len() {
                if idx == 0 {
                    if self.items[idx].error {
                        return Err(())
                    }

                    // this is anoying
                    let req: &RequestInfo = unsafe {
                        mem::transmute(&self.items[idx].req)
                    };
                    match self.items[idx].task.poll_io(&mut self.stream, req)
                    {
                        Ok(Async::Ready(val)) => {
                            let mut item = self.items.pop_front().unwrap();
                            if !val {
                                item.eof = true;
                                self.inactive.push(item);
                            }
                            continue
                        },
                        Ok(Async::NotReady) => (),
                        Err(_) => {
                            // it is not possible to recover from error
                            // during task handling, so just drop connection
                            return Err(())
                        }
                    }
                } else if !self.items[idx].finished {
                    match self.items[idx].task.poll() {
                        Ok(Async::Ready(_)) =>
                            self.items[idx].finished = true,
                        Ok(Async::NotReady) => (),
                        Err(_) =>
                            self.items[idx].error = true,
                    }
                }
                idx += 1;
            }

            // check for parse error
            if self.items.is_empty() && self.error {

            }
            
            // read incoming data
            if !self.error {
                match self.reader.parse(&mut self.stream) {
                    Ok(Async::Ready((req, payload))) => {
                        let info = RequestInfo::new(&req);
                        self.items.push_back(
                            Entry {task: self.router.call(req, payload),
                                   req: info,
                                   eof: false,
                                   error: false,
                                   finished: false});
                    }
                    Ok(Async::NotReady) =>
                        return Ok(Async::NotReady),
                    Err(err) => return Err(())
                        //self.items.push_back(
                        //    Entry {task: Task::reply(err),
                        //           eof: false,
                        //           error: false,
                        //           finished: false})
                }
            }
        }
    }
}