ludus-repl/listener.ts

import { run } from "@ludus/ludus-js-pure"
import { unlinkSync, readFileSync } from "node:fs"

function random_port () {
  return Math.floor(Math.random() * 10000)
}

export async function listen () {
  let id = random_port()
  let unix_socket = `/tmp/ludus-${id}.sock`
  // make sure the socket path isn't already taken
  while (await Bun.file(unix_socket).exists()) {
    id = random_port()
    unix_socket = `/tmp/ludus-${id}.sock`
  }
  const repl_file_path = ".lrepl"
  const repl_info = { unix_socket }
  const repl_file = Bun.file(repl_file_path)
  await Bun.write(repl_file, JSON.stringify(repl_info))

  console.log(`Ludus REPL listening on unix://${unix_socket}`)

  Bun.listen({
    //hostname: "localhost",
    //port,
    unix: unix_socket,
    socket: {
      open: (_) => {console.log("=== === ===") },
      data: (_, data) => {
        const source = data.toString("utf-8")
        const result = run(source)
        if (!result.errors) console.log("=>", result.result)
        else {
          console.log("Ludus had some errors:")
          console.log(result.errors)
        }
      },
      error: (socket, error) => { console.log(error); socket.end() }
    }
  })


  process.on("exit", async function () {
    try { cleanup(repl_file_path, unix_socket) } catch (e) {}
    console.log("\nGoodbye.")
  })

  process.on("SIGINT", () => process.exit())

  // Below here, I'm trying to get ctrl-d to work to close the listener
  // the while (true) loop locks the listener
  // see: https://github.com/oven-sh/bun/issues/3255
  // this should be doable with process.stdin.on("close"...)
  //const mystdin = Bun.file("/dev/stdin").stream().getReader()

  // while (true) {
  //   const {done, value} = await mystdin.read()
  //   if (done) process.exit()
  //   console.log(value)
  // }

}

// Don't delete an .lrepl we don't own
function cleanup (path: string, my_socket: string) {
  const repl_file = readFileSync(path).toString("utf-8")
  let their_socket
  try { their_socket = JSON.parse(repl_file).unix_socket } catch (e) { return }
  if (their_socket === my_socket) {
    unlinkSync(path)
    unlinkSync(my_socket)
  }
}

// await listen()