/**
 * Generic browser-side download helper for plain-text files.
 *
 * Mirrors `downloadCsv` in `./csv.ts` but takes an explicit MIME type so the
 * same code path can serve X12 (text/x12), JSON (application/json), or any
 * other text payload without growing a one-off helper per format.
 *
 * The implementation is identical to `downloadCsv` minus the BOM prepending
 * (we want byte-faithful X12 — prepending a BOM corrupts the ISA segment).
 *
 * Safe to call from SSR/Node — guards against a missing `document`.
 */
export function downloadTextFile(
  filename: string,
  mimeType: string,
  text: string,
): void {
  if (typeof document === "undefined" || typeof URL === "undefined") return;
  const blob = new Blob([text], { type: `${mimeType};charset=utf-8` });
  const url = URL.createObjectURL(blob);
  const a = document.createElement("a");
  a.href = url;
  a.download = filename;
  // Some browsers require the link to be in the DOM before .click() works.
  a.style.display = "none";
  document.body.appendChild(a);
  a.click();
  document.body.removeChild(a);
  // Defer revoke so the browser has the URL handle when the download kicks off.
  queueMicrotask(() => URL.revokeObjectURL(url));
}