import { isGenericSessionTitle } from "@/lib/agent-reply";

function hanLength(value: string): number {
  return Array.from(value.replace(/\s+/g, "")).length;
}

function clipHan(value: string, maxChars: number): string {
  const characters = Array.from(value);
  return characters.length > maxChars ? characters.slice(0, maxChars).join("") : value;
}

const BIRTH_STAMP = /\d{4}年\d{1,2}月(?:\d{1,2}日)?|\d{1,2}:\d{2}/;
const DATED_ENTRY_TITLE = /^\d{1,2}月\d{1,2}日\s*·\s*(?:今日节奏|生时校正)$/;

export function sanitizeSessionTitle(raw: string): string | null {
  if (/[\r\n]/.test(raw)) return null;
  const stripped = raw
    .replace(/[“”"‘’'「」『』《》]/g, "")
    .replace(/[。．.!?！？、，,;；：:]+$/u, "")
    .replace(/\s+/g, " ")
    .trim();
  if (!stripped) return null;
  if (hanLength(stripped) < 2) return null;
  if (isGenericSessionTitle(stripped)) return null;
  if (BIRTH_STAMP.test(stripped)) return null;
  const clipped = clipHan(stripped, 14);
  if (hanLength(clipped) < 6) return null;
  return clipped;
}

export function isAutoDerivedSessionTitle(title: string): boolean {
  const text = title.replace(/\s+/g, " ").trim();
  if (!text) return true;
  if (isGenericSessionTitle(text)) return true;
  if (DATED_ENTRY_TITLE.test(text)) return true;
  if (/…$|\.{3}$/.test(text)) return true;
  return false;
}

export function shouldGenerateSessionTitle(
  session: { title?: string | null; sessionType?: string | null },
  storedHistory: readonly unknown[],
): boolean {
  if (storedHistory.length > 0) return false;
  if (session.sessionType === "birth_time_rectification") return false;
  const title = typeof session.title === "string" ? session.title : "";
  if (DATED_ENTRY_TITLE.test(title.replace(/\s+/g, " ").trim())) return false;
  return isAutoDerivedSessionTitle(title);
}