use crate::service::{DerivablePath, DerivationError, Keyforkd};
use keyfork_frame::asyncext::{try_decode_from, try_encode_to};
use std::{io::Error, path::{Path, PathBuf}};
use tokio::net::{UnixListener, UnixStream};
use tower::{Service, ServiceExt};

#[cfg(feature = "tracing")]
use tracing::debug;

async fn read_path_from_socket(
    socket: &mut UnixStream,
) -> Result<DerivablePath, Box<dyn std::error::Error + Send>> {
    let data = try_decode_from(socket).await.unwrap();
    let path: DerivablePath = bincode::deserialize(&data[..]).unwrap();
    Ok(path)
}

async fn wait_and_run(app: &mut Keyforkd, path: DerivablePath) -> Result<Vec<u8>, DerivationError> {
    app.ready().await?.call(path).await
}

#[allow(clippy::module_name_repetitions)]
pub struct UnixServer {
    listener: UnixListener,
}

impl UnixServer {
    pub fn bind(address: impl AsRef<Path>) -> Result<Self, Error> {
        let mut path = PathBuf::new();
        path.extend(address.as_ref().components());
        tokio::spawn(async move {
            let result = tokio::signal::ctrl_c().await;
            #[cfg(feature = "tracing")]
            debug!(?result, "encountered ctrl-c, performing cleanup and exiting");
            let result = tokio::fs::remove_file(&path).await;
            #[cfg(feature = "tracing")]
            if let Err(error) = result {
                debug!(%error, "unable to remove path: {}", path.display());
            }
            std::process::exit(0x80);
        });

        Ok(Self {
            listener: UnixListener::bind(address)?,
        })
    }

    pub async fn run(&mut self, app: Keyforkd) -> Result<(), Box<dyn std::error::Error>> {
        loop {
            let mut app = app.clone();
            let (mut socket, _) = self.listener.accept().await?;
            #[cfg(feature = "tracing")]
            debug!("new socket connected");
            tokio::spawn(async move {
                let path = match read_path_from_socket(&mut socket).await {
                    Ok(path) => path,
                    Err(e) => {
                        #[cfg(feature = "tracing")]
                        debug!(%e, "Error reading DerivablePath from socket");
                        let content = e.to_string().bytes().collect::<Vec<_>>();
                        let result = try_encode_to(&content[..], &mut socket).await;
                        #[cfg(feature = "tracing")]
                        if let Err(error) = result {
                            debug!(%error, "Error sending error to client");
                        }
                        return;
                    }
                };

                let response = match wait_and_run(&mut app, path).await {
                    Ok(response) => response,
                    Err(e) => {
                        #[cfg(feature = "tracing")]
                        debug!(%e, "Error reading DerivablePath from socket");
                        let content = e.to_string().bytes().collect::<Vec<_>>();
                        let result = try_encode_to(&content[..], &mut socket).await;
                        #[cfg(feature = "tracing")]
                        if let Err(error) = result {
                            debug!(%error, "Error sending error to client");
                        }
                        return;
                    }
                };

                if let Err(e) = try_encode_to(&response[..], &mut socket).await {
                    #[cfg(feature = "tracing")]
                    debug!(%e, "Error sending response to client");
                }

            });
        }
    }
}