//! For binding to sockets
use super::*;
use futures::{
    prelude::*,
};
use std::{
    marker::{
	Send,
	Unpin,
    },
    fmt,
    error,
    path::{
	Path,
	PathBuf,
    },
};
use tokio::{
    io::{
	self,
	AsyncRead,
	AsyncWrite,
    },
};

#[derive(Debug)]
pub enum BindError<E>
{
    IO(io::Error),
    Warp(warp::Error),
    Other(E),
}

impl<E: error::Error + 'static> error::Error for BindError<E>
{
    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
	Some(match &self {
	    Self::IO(io) => io,
	    Self::Other(o) => o,
	    Self::Warp(w) => w,
	})
    }
}
impl<E: fmt::Display> fmt::Display for BindError<E>
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
    {
	match self {
	    Self::IO(io) => write!(f, "io error: {}", io),
	    Self::Other(other) => write!(f, "{}", other),
	    Self::Warp(warp) => write!(f, "server error: {}", warp),
	}
    }
}


#[derive(Debug)]
pub struct BindpointParseError;

impl error::Error for BindpointParseError{}
impl fmt::Display for BindpointParseError
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
    {
	write!(f, "Failed to parse bindpoint as IP or unix domain socket")
    }
}


#[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize, PartialOrd)]
pub enum Bindpoint
{
    Unix(PathBuf),
    TCP(SocketAddr),
}

impl fmt::Display for Bindpoint
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
    {
	match self {
	    Self::Unix(unix) => write!(f, "unix:/{}", unix.to_string_lossy()),
	    Self::TCP(tcp) => write!(f, "{}", tcp),
	}
    }
}

impl std::str::FromStr for Bindpoint
{
    type Err = BindpointParseError;
    fn from_str(s: &str) -> Result<Self, Self::Err> {
	Ok(if let Ok(ip) = s.parse::<SocketAddr>() {
	    Self::TCP(ip)
	} else if s.starts_with("unix:/") {
	    Self::Unix(PathBuf::from(&s[6..].to_owned()))
	} else {
	    return Err(BindpointParseError);  
	})
    }
}

fn bind_unix(to: impl AsRef<Path>) -> io::Result<impl TryStream<Ok= impl AsyncRead + AsyncWrite + Send + Unpin + 'static + Send, Error = impl Into<Box<dyn std::error::Error + Send + Sync>>>>
{
    debug!("Binding to AF_UNIX: {:?}", to.as_ref());
    let listener = tokio::net::UnixListener::bind(to)?;
    Ok(listener)
}

pub fn serve<F>(server: warp::Server<F>, bind: Bindpoint, signal: impl Future<Output=()> + Send + 'static) -> Result<(Bindpoint, BoxFuture<'static, ()>), BindError<std::convert::Infallible>>
where F: Filter + Clone + Send + Sync + 'static,
<F::Future as TryFuture>::Ok: warp::Reply,
{
    Ok(match bind {
	Bindpoint::TCP(sock) => server.try_bind_with_graceful_shutdown(sock, signal).map(|(sock, fut)| (Bindpoint::TCP(sock), fut.boxed())).map_err(BindError::Warp)?,
	Bindpoint::Unix(unix) => {
	    (Bindpoint::Unix(unix.clone()),
	     server.serve_incoming_with_graceful_shutdown(bind_unix(unix).map_err(BindError::IO)?, signal).boxed())
	},
    })
}

impl From<SocketAddr> for Bindpoint
{
    fn from(from: SocketAddr) -> Self
    {
	Self::TCP(from)
    }
}

pub fn try_serve<F>(server: warp::Server<F>, bind: impl TryBindpoint, signal: impl Future<Output=()> + Send + 'static) -> Result<(Bindpoint, BoxFuture<'static, ()>), BindError<impl error::Error + 'static>>
where F: Filter + Clone + Send + Sync + 'static,
<F::Future as TryFuture>::Ok: warp::Reply,
{
    serve(server, bind.try_parse().map_err(BindError::Other)?, signal).map_err(BindError::coerce)
}

pub trait TryBindpoint: Sized
{
    type Err: error::Error + 'static;
    fn try_parse(self) -> Result<Bindpoint, Self::Err>;
}

impl TryBindpoint for Bindpoint
{
    type Err = std::convert::Infallible;
    fn try_parse(self) -> Result<Bindpoint, Self::Err>
    {
	Ok(self)
    }
}

impl<T: AsRef<str>> TryBindpoint for T
{
    type Err = BindpointParseError;
    fn try_parse(self) -> Result<Bindpoint, Self::Err>
    {
	self.as_ref().parse()
    }
}

impl BindError<std::convert::Infallible>
{
    pub fn coerce<T>(self) -> BindError<T>
    {
	match self {
	    Self::Warp(w) => BindError::Warp(w),
	    Self::IO(w) => BindError::IO(w),
	    #[cold] _ => unreachable!(),
	}
    }
}