/**
 * Split text into chunks that respect a maximum length, avoiding
 * splits in the middle of Unicode surrogate pairs.
 */
export function splitText(text: string, maxLength: number): string[] {
  if (text.length <= maxLength) {
    return [text];
  }

  const chunks: string[] = [];
  let cursor = 0;
  while (cursor < text.length) {
    let end = Math.min(cursor + maxLength, text.length);
    // Avoid splitting a surrogate pair
    if (
      end < text.length &&
      text.charCodeAt(end - 1) >= 0xd800 &&
      text.charCodeAt(end - 1) <= 0xdbff
    ) {
      end--;
    }
    chunks.push(text.slice(cursor, end));
    cursor = end;
  }
  return chunks;
}