use std::time::Duration;
use tokio::io::{AsyncReadExt, AsyncWriteExt};
use tokio::net::TcpStream;
use tokio::sync::broadcast::{self, error::TryRecvError};
use tokio::task::JoinHandle;
use tokio::time::sleep;

pub struct Process {
    inner: TcpStream,
    input: Option<broadcast::Receiver<String>>,
    output: Option<broadcast::Sender<String>>,
}

impl Process {
    /// spawns the server
    pub async fn spawn() -> anyhow::Result<Self> {
        let stream = TcpStream::connect("localhost:6859").await?;
        Ok(Self {
            inner: stream,
            input: None,
            output: None,
        })
    }

    pub fn input(mut self, input: broadcast::Receiver<String>) -> Self {
        self.input = Some(input);
        self
    }

    pub fn output(mut self, output: broadcast::Sender<String>) -> Self {
        self.output = Some(output);
        self
    }

    pub fn link(mut self) -> JoinHandle<()> {
        define_print!("process");
        let mut input = self.input.unwrap();
        let output = self.output.unwrap();
        tokio::spawn(async move {
            let mut stdout = [0; 4096];
            loop {
                if output.receiver_count() == 0 {
                    sleep(Duration::from_millis(500)).await;
                    continue;
                }
                match input.try_recv() {
                    Err(e) => match e {
                        TryRecvError::Closed => fail!("closed"),
                        _ => sleep(Duration::from_millis(100)).await,
                    },
                    Ok(mut s) => {
                        input!("{s}");
                        s.push('\n');
                        self.inner.write_all(s.as_bytes()).await.unwrap();
                        self.inner.flush().await.unwrap();
                    }
                }

                let string = {
                    let n = tokio::select! {
                        n = self.inner.read(&mut stdout) => n.unwrap(),
                        () = sleep(Duration::from_millis(100)) => continue,
                    };
                    String::from_utf8_lossy(&strip_ansi_escapes::strip(&stdout[..n])).into_owned()
                };
                for line in string.lines() {
                    output!("{line}");
                }
                output.send(string).unwrap();
                sleep(Duration::from_millis(100)).await;
            }
        })
    }
}