use std::cell::UnsafeCell;
use std::marker::PhantomData;
use std::ops::Deref;
use log::error;
use tokio::io::{AsyncRead, AsyncWrite};
use tokio::sync::mpsc::{channel, Receiver, Sender};
use tokio::task;
use splatoon_server_rust::reggie::{UnitPacketRead, UnitPacketWrite};

#[derive(Clone)]
pub struct SendingBufferConnection(Sender<Vec<u8>>);

pub struct SplittableBufferConnection(SendingBufferConnection, Receiver<Vec<u8>>);

impl AsRef<SendingBufferConnection> for SplittableBufferConnection{
    fn as_ref(&self) -> &SendingBufferConnection {
        &self.0
    }
}

impl Deref for SplittableBufferConnection{
    type Target = SendingBufferConnection;

    fn deref(&self) -> &Self::Target {
        self.as_ref()
    }
}



impl<T: Send + Unpin + AsyncWrite + AsyncRead + 'static> From<T> for SplittableBufferConnection{
    fn from(value: T) -> Self {
        Self::new(value)
    }
}

impl SplittableBufferConnection {
    fn new<T: Send + Unpin + AsyncWrite + AsyncRead + 'static>(stream: T) -> Self {
        let (outside_send, inside_recv) = channel::<Vec<u8>>(10);
        let (inside_send, outside_recv) = channel::<Vec<u8>>(10);

        task::spawn(async move {
            let sender = inside_send;
            let mut recver = inside_recv;
            let mut stream = stream;
            loop {
                tokio::select! {
                    data = recver.recv() => {
                        let Some(data) = data else {
                            break;
                        };

                        if let Err(e) = stream.send_buffer(&data[..]).await{
                            error!("error sending data to backend: {}", e);
                            break;
                        }
                    },
                    data = stream.read_buffer() => {
                        let data = match data{
                            Ok(d) => d,
                            Err(e) => {
                                error!("error reveiving data from backend: {}", e);
                                break;
                            }
                        };

                        if let Err(e) = sender.send(data).await{
                            error!("a send error occurred {}", e);
                            return;
                        }
                    },
                }
            }
        });

        Self(SendingBufferConnection(outside_send), outside_recv)
    }
}

impl SendingBufferConnection{
    pub async fn send(&self, buffer: Vec<u8>) -> Option<()>{
        self.0.send(buffer).await.ok()
    }
}

impl SplittableBufferConnection{
    pub async fn recv(&mut self) -> Option<Vec<u8>>{
        self.1.recv().await
    }

    pub fn duplicate_sender(&self) -> SendingBufferConnection{
        self.0.clone()
    }
}