type CanvasRuntimeEndpointOptions = {
  internalOrigin?: string;
  port?: string;
};

function normalizeInternalOrigin(value: string) {
  const url = new URL(value);
  url.pathname = "/";
  url.search = "";
  url.hash = "";
  return url.toString();
}

export function resolveCanvasRuntimeEndpoint(
  path: string,
  requestUrl: string,
  options: CanvasRuntimeEndpointOptions = {}
) {
  const configuredOrigin = String(
    options.internalOrigin ?? process.env.CANVAS_RUNTIME_INTERNAL_ORIGIN ?? ""
  ).trim();
  if (configuredOrigin) {
    return new URL(path, normalizeInternalOrigin(configuredOrigin)).toString();
  }

  const port = String(options.port ?? process.env.PORT ?? "").trim();
  if (/^\d{1,5}$/.test(port) && Number(port) > 0 && Number(port) <= 65_535) {
    return new URL(path, `http://127.0.0.1:${port}`).toString();
  }

  return new URL(path, requestUrl).toString();
}