/**
 * The same rule the server applies to every name in the Generator's lists (server/src/services/nameThemes.ts), so the
 * editor can point out a bad name while it's being typed. The server checks again on save and is the one that decides.
 */
export function normalizeNameInput(raw: string): string | null {
  const folded = raw
    .normalize("NFD")
    .replace(/[̀-ͯ]/g, "")
    .trim()
    .toLowerCase();
  return /^[a-z0-9](?:[a-z0-9-]{0,28}[a-z0-9])?$/.test(folded) ? folded : null;
}

/** Names are separated by line breaks, commas, semicolons or spaces. */
export function splitNames(text: string): string[] {
  return text.split(/[\s,;]+/).filter(Boolean);
}

/** The usable names in `text` (folded and de-duplicated, in the order written) and whatever couldn't be used. */
export function parseNames(text: string): { names: string[]; invalid: string[] } {
  const names: string[] = [];
  const invalid: string[] = [];
  const seen = new Set<string>();
  for (const token of splitNames(text)) {
    const clean = normalizeNameInput(token);
    if (clean === null) invalid.push(token);
    else if (!seen.has(clean)) {
      seen.add(clean);
      names.push(clean);
    }
  }
  return { names, invalid };
}