use std::io::{Error, ErrorKind};
use std::time::Duration;

use futures::future::try_join;
use quinn::{RecvStream, SendStream};
use rust_util::util_msg;
use rust_util::util_msg::MessageType;
use tokio::{select, time};
use tokio::io::{AsyncRead, AsyncReadExt, AsyncWrite, AsyncWriteExt};
use tokio::net::TcpStream;

#[derive(Debug)]
enum StreamDirection {
    Up,
    Down,
}

pub async fn transfer_for_server_to_remote(recv: RecvStream, send: SendStream, remote_addr: &str, local_addr: &str, proxy_addr: String, conn_count: String) -> Result<(), String> {
    let mut outbound = match TcpStream::connect(&proxy_addr).await {
        Ok(outbound) => outbound,
        Err(e) => {
            return Err(format!("[conn {}] Failed to connect to: {}, err: {}", &conn_count, &proxy_addr, e));
        }
    };
    if let (in_peer_addr, in_local_addr, Ok(ref out_local_addr), Ok(ref out_peer_addr))
    = (remote_addr, local_addr, outbound.local_addr(), outbound.peer_addr()) {
        let peer = format!("{} -> [{} * {}] -> {}", in_peer_addr, in_local_addr, out_local_addr, out_peer_addr);
        information!("[conn {}] New server-remote tcp connection: {}", &conn_count, peer);
    }
    let (mut ri, mut wi) = (recv, send);
    let (mut ro, mut wo) = outbound.split();
    inner_transfer(&mut ri, &mut wi, &mut ro, &mut wo, conn_count).await
}

pub async fn transfer_for_client_to_server(mut inbound: TcpStream, recv: RecvStream, send: SendStream, remote_addr: &str, local_addr: &str, conn_count: String) -> Result<(), String> {
    if let (Ok(ref in_peer_addr), Ok(ref in_local_addr), out_local_addr, out_peer_addr)
    = (inbound.peer_addr(), inbound.local_addr(), local_addr, remote_addr) {
        let peer = format!("{} -> [{} * {}] -> {}", in_peer_addr, in_local_addr, out_local_addr, out_peer_addr);
        information!("[conn {}] New client-server tcp connection: {}", &conn_count, peer);
    }
    let (mut ri, mut wi) = inbound.split();
    let (mut ro, mut wo) = (recv, send);
    inner_transfer(&mut ri, &mut wi, &mut ro, &mut wo, conn_count).await
}

async fn inner_transfer<'a, R1, W1, R2, W2>(mut ri: &'a mut R1, mut wi: &'a mut W1, mut ro: &'a mut R2, mut wo: &'a mut W2, conn_count: String) -> Result<(), String>
    where R1: AsyncRead + Unpin + ?Sized, W1: AsyncWrite + Unpin + ?Sized,
          R2: AsyncRead + Unpin + ?Sized, W2: AsyncWrite + Unpin + ?Sized {
    // IO copy timeout 6 HOURS
    let tcp_io_copy_timeout = Duration::from_secs(6 * 3600);
    let shutdown_tcp_timeout = Duration::from_secs(60);
    let (client_to_server_tx, client_to_server_rx) = tokio::sync::oneshot::channel::<bool>();
    let (server_to_client_tx, server_to_client_rx) = tokio::sync::oneshot::channel::<bool>();
    let client_to_server = async {
        let r = select! {
            _timeout = time::sleep(tcp_io_copy_timeout) => {
                failure!("[conn {}] TCP copy client -> server timeout", &conn_count);
                Err(Error::new(ErrorKind::TimedOut, "timeout"))
            }
            _tcp_break = client_to_server_rx => {
                failure!("[conn {}] TCP copy client -> server shutdown", &conn_count);
                Err(Error::new(ErrorKind::BrokenPipe, "shutdown"))
            }
            data_copy_result = copy_data(&mut ri, &mut wo, StreamDirection::Up, &conn_count) => {
                match data_copy_result {
                    Err(e) => {
                        failure!("[conn {}] TCP copy client -> server error: {}", &conn_count, e);
                        Err(e)
                    },
                    Ok(r) => {
                        information!("[conn {}] TCP copy client -> server success: {} byte(s)", &conn_count, r);
                        Ok(r)
                    },
                }
            }
        };
        information!("[conn {}] Close client to server connection", &conn_count);
        match time::timeout(shutdown_tcp_timeout, wo.shutdown()).await {
            Err(e) => warning!("[conn {}] TCP close client -> server timeout: {}", &conn_count, e),
            Ok(Err(e)) => warning!("[conn {}] TCP close client -> server error: {}", &conn_count, e),
            _ => {}
        }
        time::sleep(Duration::from_secs(2)).await;
        let _ = server_to_client_tx.send(true);
        r
    };
    let server_to_client = async {
        let r = select! {
            _timeout = time::sleep(tcp_io_copy_timeout) => {
                failure!("[conn {}] TCP copy server -> client timeout", &conn_count);
                Err(Error::new(ErrorKind::TimedOut, "timeout"))
            }
            _tcp_break = server_to_client_rx => {
                failure!("[conn {}] TCP copy server -> client shutdown", &conn_count);
                Err(Error::new(ErrorKind::BrokenPipe, "shutdown"))
            }
            data_copy_result = copy_data(&mut ro, &mut wi, StreamDirection::Down, &conn_count) => {
                match data_copy_result {
                    Err(e) => {
                        failure!("[conn {}] TCP copy server -> client error: {}", &conn_count, e);
                        Err(e)
                    },
                    Ok(r) => {
                        information!("[conn {}] TCP copy server -> client success: {} byte(s)", &conn_count, r);
                        Ok(r)
                    },
                }
            }
        };
        information!("[conn {}] Close server to client connection", &conn_count);
        match time::timeout(shutdown_tcp_timeout, wi.shutdown()).await {
            Err(e) => warning!("[conn {}] TCP close server -> client timeout: {}", &conn_count, e),
            Ok(Err(e)) => warning!("[conn {}] TCP close server -> client error: {}", &conn_count, e),
            _ => {}
        }
        time::sleep(Duration::from_secs(2)).await;
        let _ = client_to_server_tx.send(true);
        r
    };
    let r = match try_join(client_to_server, server_to_client).await {
        Err(e) => Err(format!("[conn {}] Failed try_join: {}", &conn_count, e)),
        Ok((upstream_bytes, downstream_bytes)) => {
            information!("[conn {}] Finished, proxy-in: {} bytes, proxy-out: {} bytes",
                          &conn_count, upstream_bytes, downstream_bytes
            );
            Ok(())
        }
    };
    r
}

// fn is_in_peer_addr_matches(inbound: &TcpStream, allow_ips: &[IpAddressMask]) -> bool {
//     if let Ok(ref in_peer_addr) = inbound.peer_addr() {
//         if let Some(ip_filter) = &*GLOBAL_TEMP_IP_FILTER.read().unwrap() {
//             if let Some(ip) = ip_filter.is_ip_address_matches(in_peer_addr) {
//                 return true;
//             }
//         }
//         if !allow_ips.is_empty() {
//             // ONLY if allow ips is not config, returns true
//             // If default deny IPs, should config like: "allow_ips": ["127.0.0.1"]
//             return allow_ips.iter().any(|ip| ip.is_matches(in_peer_addr));
//         }
//     }
//     true
// }

async fn copy_data<'a, R, W>(
    reader: &'a mut R, writer: &'a mut W, direction: StreamDirection, conn_count: &str) -> tokio::io::Result<u64>
    where R: AsyncRead + Unpin + ?Sized,
          W: AsyncWrite + Unpin + ?Sized {
    let mut total_copied_bytes = 0_u64;
    let mut buff = vec![0; 1024 * 4];
    loop {
        match reader.read(&mut buff).await {
            Ok(0) => return Ok(total_copied_bytes),
            Ok(n) => {
                util_msg::when(MessageType::DEBUG, || {
                    debugging!("[conn {}] Direction: {:?}, {} bytes: {:02x?}", conn_count, direction, n, &buff[..n]);
                    debugging!("[conn {}] Direction: {:?}, {} string: {}", conn_count, direction, n, String::from_utf8_lossy(&buff[..n]).to_string());
                });
                match writer.write_all(&buff[..n]).await {
                    Ok(_) => {
                        total_copied_bytes += n as u64;
                    }
                    Err(e) => return Err(e),
                }
            }
            Err(e) => return Err(e),
        }
    }
}