/**
 * Mid-session spoken birth-time windows are not a search-window change.
 * Detect them so the route can answer with a fixed reply and skip the model.
 *
 * Clock-shaped text is not enough (BUG-631): dated life events and other
 * non-birth sentences that happen to contain HH:MM must still reach the model.
 */

const CLOCK = /(?:[01]?\d|2[0-3])\s*[:：点]\s*(?:半|[0-5]?\d(?:\s*分)?)?/;
const RANGE_SEP = /\s*(?:到|至|[-–—~～])\s*/;
const AROUND = /\s*(?:左右|前后)/;
const RANGE_PATTERN = new RegExp(`(${CLOCK.source})${RANGE_SEP.source}(${CLOCK.source})`);
const AROUND_PATTERN = new RegExp(`(${CLOCK.source})${AROUND.source}`);
const BIRTH_CONTEXT = /出生时间|出生|生于|时辰|几点生|钟点是|(?<![发产陌])生的/;
const CALENDAR_DATE = /\d{4}\s*年|\d{1,2}\s*月|\d{1,2}\s*日/;
const BARE_FILLER = /上午|下午|傍晚|夜里|晚上|清晨|中午|我的|我|是|大概|大约|差不多|可能|就|在|的|了|吧|啊|呢|嗯|[，。,.、\s]|[-–—~～]/g;

export type DeclaredBirthWindow =
  | { kind: "range"; start: string; end: string }
  | { kind: "around"; time: string };

export function parseDeclaredBirthWindow(message: string): DeclaredBirthWindow | null {
  const text = message.trim();
  if (!text) return null;
  const range = RANGE_PATTERN.exec(text);
  if (range) {
    const start = normalizeClock(range[1] ?? "");
    const end = normalizeClock(range[2] ?? "");
    if (start && end && start !== end && shouldInterceptDeclaredWindow(text, range)) {
      return { kind: "range", start, end };
    }
    if (start && end && start !== end) return null;
  }
  const around = AROUND_PATTERN.exec(text);
  if (around) {
    const time = normalizeClock(around[1] ?? "");
    if (time && shouldInterceptDeclaredWindow(text, around)) {
      return { kind: "around", time };
    }
  }
  return null;
}

function shouldInterceptDeclaredWindow(text: string, match: RegExpExecArray): boolean {
  if (BIRTH_CONTEXT.test(text)) return true;
  if (CALENDAR_DATE.test(text)) return false;
  return isBareClockUtterance(text, match);
}

function isBareClockUtterance(text: string, match: RegExpExecArray): boolean {
  const leftover = `${text.slice(0, match.index)}${text.slice(match.index + match[0].length)}`;
  return leftover.replace(BARE_FILLER, "") === "";
}

function normalizeClock(raw: string): string | null {
  const half = /([01]?\d|2[0-3])\s*[:：点]\s*半/.exec(raw);
  if (half) {
    const hour = Number(half[1]);
    if (!Number.isInteger(hour) || hour > 23) return null;
    return `${String(hour).padStart(2, "0")}:30`;
  }
  const withMinutes = /([01]?\d|2[0-3])\s*[:：点]\s*([0-5]?\d)/.exec(raw);
  if (withMinutes) {
    const hour = Number(withMinutes[1]);
    const minute = Number(withMinutes[2]);
    if (!Number.isInteger(hour) || hour > 23 || !Number.isInteger(minute) || minute > 59) return null;
    return `${String(hour).padStart(2, "0")}:${String(minute).padStart(2, "0")}`;
  }
  const hourOnly = /([01]?\d|2[0-3])\s*点/.exec(raw);
  if (!hourOnly) return null;
  const hour = Number(hourOnly[1]);
  if (!Number.isInteger(hour) || hour > 23) return null;
  return `${String(hour).padStart(2, "0")}:00`;
}