const MAX_NAME = 32;
const MAX_BODY = 500;

export class GuestCommentValidationError extends Error {
  constructor(message: string) {
    super(message);
    this.name = "GuestCommentValidationError";
  }
}

export function normalizeGuestDisplayName(raw: string): string {
  const t = raw.trim();
  if (!t) {
    throw new GuestCommentValidationError("请填写昵称");
  }
  if (t.length > MAX_NAME) {
    throw new GuestCommentValidationError("昵称过长");
  }
  return t;
}

/** 返回 trim 后正文；违规抛 GuestCommentValidationError（由 API 映射为 400） */
export function validateGuestCommentBody(raw: string): string {
  const t = raw.trim();
  if (!t) {
    throw new GuestCommentValidationError("请填写内容");
  }
  if (t.length > MAX_BODY) {
    throw new GuestCommentValidationError("内容过长");
  }
  if (/https?:\/\//i.test(t) || /\bwww\./i.test(t)) {
    throw new GuestCommentValidationError("不能包含链接");
  }
  if (/\[[^\]]*\]\([^)]*\)/.test(t)) {
    throw new GuestCommentValidationError("不能使用 Markdown 链接");
  }
  return t;
}