/**
 * 脱敏 —— 凡要落库 / 上接口的厂商原话都先过这里(设计稿 §9.4)。
 * 明文、base64(SMTP AUTH 的形)、URL 编码三形都换掉。
 */
const MIN_SECRET_CHARS = 4;

export function secretVariants(secret: string): string[] {
  if (secret.length < MIN_SECRET_CHARS) return [];
  const variants = [secret, Buffer.from(secret, 'utf8').toString('base64'), encodeURIComponent(secret)];
  return [...new Set(variants.filter((v) => v.length >= MIN_SECRET_CHARS))];
}

function escapeRegex(s: string): string {
  return s.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
}

export function redactSecrets(text: string, secrets: readonly string[]): string {
  let out = text;
  for (const secret of secrets) {
    for (const variant of secretVariants(secret)) {
      out = out.replace(new RegExp(escapeRegex(variant), 'g'), '***');
    }
  }
  return out;
}

/** 错误 → 一句话;nodemailer / imapflow 把服务器回话挂在 `response` / `responseText` 上,一并带上 */
export function errorText(error: unknown): string {
  if (error instanceof Error) {
    const bag = error as Error & { response?: unknown; responseText?: unknown };
    const response = typeof bag.response === 'string' ? bag.response : typeof bag.responseText === 'string' ? bag.responseText : '';
    return response === '' || response === error.message ? error.message : `${error.message} —— ${response}`;
  }
  if (error === undefined || error === null) return '未知错误';
  return String(error);
}