// The byte pipe to a smolmaild server. Browsers cannot open TCP sockets, so
// bytes travel through the local bridge's WebSocket relay unchanged; the
// Noise session lives in this page either way.

const BRIDGE = `${location.protocol === "https:" ? "wss" : "ws"}://${location.host}`;

export function connectStream(host, port, timeoutMs = 0) {
  return new Promise((resolve, reject) => {
    const socket = new WebSocket(`${BRIDGE}/tcp/${host}/${port}`);
    socket.binaryType = "arraybuffer";
    const stream = {
      send: bytes => socket.send(bytes),
      close: () => socket.close(),
      onData: null,
      onClose: null,
    };
    // Settings' timeout only governs this; the WebSocket may otherwise never
    // fire open, error, or close if something between here and the bridge
    // just drops packets.
    const timer = timeoutMs ? setTimeout(() => {
      socket.close();
      reject(new Error(`could not reach ${host}:${port} within ${timeoutMs / 1000}s`));
    }, timeoutMs) : null;
    socket.onopen = () => { clearTimeout(timer); resolve(stream); };
    socket.onerror = () => { clearTimeout(timer); reject(new Error(`cannot reach the bridge at ${BRIDGE}`)); };
    socket.onmessage = event => stream.onData?.(new Uint8Array(event.data));
    socket.onclose = () => stream.onClose?.();
  });
}