use axum::{
    Router,
    extract::connect_info,
};
use futures::ready;
use hyper::{
    client::connect::{Connected, Connection},
    server::accept::Accept,
};
use snafu::prelude::*;
use std::{
    io,
    path::Path,
    pin::Pin,
    sync::Arc,
    task::{Context, Poll},
};
use tokio::{
    io::{AsyncRead, AsyncWrite},
    net::{unix::UCred, UnixListener, UnixStream},
};
use tower::BoxError;

use crate::{
    error::*,
    utils::fs::FSPermissions,
};

pub struct ServerAccept {
    uds: UnixListener,
}

impl ServerAccept {
    pub fn new(uds: UnixListener) -> ServerAccept {
        ServerAccept {
            uds,
        }
    }
}

impl Accept for ServerAccept {
    type Conn = UnixStream;
    type Error = BoxError;

    fn poll_accept(
        self: Pin<&mut Self>,
        cx: &mut Context<'_>,
    ) -> Poll<Option<Result<Self::Conn, Self::Error>>> {
        let (stream, _addr) = ready!(self.uds.poll_accept(cx))?;
        Poll::Ready(Some(Ok(stream)))
    }
}

pub struct ClientConnection {
    stream: UnixStream,
}

impl AsyncWrite for ClientConnection {
    fn poll_write(
        mut self: Pin<&mut Self>,
        cx: &mut Context<'_>,
        buf: &[u8],
    ) -> Poll<Result<usize, io::Error>> {
        Pin::new(&mut self.stream).poll_write(cx, buf)
    }

    fn poll_flush(
        mut self: Pin<&mut Self>,
        cx: &mut Context<'_>,
    ) -> Poll<Result<(), io::Error>> {
        Pin::new(&mut self.stream).poll_flush(cx)
    }

    fn poll_shutdown(
        mut self: Pin<&mut Self>,
        cx: &mut Context<'_>,
    ) -> Poll<Result<(), io::Error>> {
        Pin::new(&mut self.stream).poll_shutdown(cx)
    }
}

impl AsyncRead for ClientConnection {
    fn poll_read(
        mut self: Pin<&mut Self>,
        cx: &mut Context<'_>,
        buf: &mut tokio::io::ReadBuf<'_>,
    ) -> Poll<io::Result<()>> {
        Pin::new(&mut self.stream).poll_read(cx, buf)
    }
}

impl Connection for ClientConnection {
    fn connected(&self) -> Connected {
        Connected::new()
    }
}

#[derive(Clone, Debug)]
#[allow(dead_code)]
pub struct UdsConnectInfo {
    peer_addr: Arc<tokio::net::unix::SocketAddr>,
    peer_cred: UCred,
}

impl connect_info::Connected<&UnixStream> for UdsConnectInfo {
    fn connect_info(target: &UnixStream) -> Self {
        let peer_addr = target.peer_addr().unwrap();
        let peer_cred = target.peer_cred().unwrap();

        Self {
            peer_addr: Arc::new(peer_addr),
            peer_cred,
        }
    }
}

/// Serve a webapp on UNIX socket path
pub async fn serve(path: &Path, app: Router) -> Result<(), Error> {
    let _ = tokio::fs::remove_file(&path).await;
    tokio::fs::create_dir_all(path.parent().unwrap())
        .await
        .unwrap();

    // TODO: make proper permissions
    // Apply 777 permissions
    FSPermissions::new().chmod(0o777).apply_to(&path).await?;
    
    let uds = UnixListener::bind(path.clone())
        .context(SocketCreateSnafu { path: path.clone() })?;
    hyper::Server::builder(ServerAccept::new(uds))
        .serve(app.into_make_service_with_connect_info::<UdsConnectInfo>())
        .await.context(ServerSnafu)?;

    Ok(())
}