use anyhow::{Context, Result};
use hyper::{body::Incoming, server::conn::http1};
use hyper_util::{rt::TokioIo, service::TowerToHyperService};
use serve_esm::{Handler, create_handler};
use tokio::{
    io::{AsyncRead, AsyncWrite},
    net::{TcpListener, UnixListener},
};

#[tokio::main]
async fn main() -> Result<()> {
    let root = std::env::var_os("TARGET_DIR").context("TARGET_DIR is required")?;
    let handler = create_handler(root).context("opening TARGET_DIR")?;
    if let Some(path) = std::env::var_os("SOCKET_PATH") {
        let listener = UnixListener::bind(&path)?;
        eprintln!("listening on {}", std::path::Path::new(&path).display());
        loop {
            serve(listener.accept().await?.0, handler.clone());
        }
    } else {
        let address = std::env::var("LISTEN").unwrap_or_else(|_| "0.0.0.0:8000".into());
        let listener = TcpListener::bind(address).await?;
        eprintln!("listening on http://{}", listener.local_addr()?);
        loop {
            serve(listener.accept().await?.0, handler.clone());
        }
    }
}

fn serve<I>(io: I, handler: Handler<Incoming>)
where
    I: AsyncRead + AsyncWrite + Unpin + Send + 'static,
{
    tokio::spawn(async move {
        let connection = http1::Builder::new()
            .serve_connection(TokioIo::new(io), TowerToHyperService::new(handler));
        if let Err(error) = connection.await {
            eprintln!("HTTP connection failed: {error}");
        }
    });
}