function generateDailyPacket(stock_code, startDate, days, basePrice) {
  const data = [];
  let prevClose = Number(basePrice);
  const toStrDate = (dateVal) => (typeof dateVal === 'number' ? String(dateVal) : dateVal);
  const addDays = (yyyymmdd, delta) => {
    const y = parseInt(yyyymmdd.slice(0, 4), 10);
    const m = parseInt(yyyymmdd.slice(4, 6), 10) - 1;
    const d = parseInt(yyyymmdd.slice(6, 8), 10);
    const dt = new Date(y, m, d);
    dt.setDate(dt.getDate() + delta);
    const yyyy = dt.getFullYear();
    const mm = String(dt.getMonth() + 1).padStart(2, '0');
    const dd = String(dt.getDate()).padStart(2, '0');
    return `${yyyy}${mm}${dd}`;
  };
  const randDrift = () => (Math.random() - 0.5) * 0.02; // 每日 ±1% 漂移
  const spread = 0.00050; // 买卖点差（可按需要调整）

  let date = toStrDate(startDate);
  for (let i = 0; i < days; i++) {
    const open = +(prevClose * (1 + randDrift())).toFixed(5);
    const close = +(open * (1 + randDrift())).toFixed(5);
    const highRaw = Math.max(open, close) * (1 + Math.random() * 0.01);
    const lowRaw = Math.min(open, close) * (1 - Math.random() * 0.01);
    const high = +highRaw.toFixed(5);
    const low = +lowRaw.toFixed(5);

    const tick_qty = Math.floor(1000 + Math.random() * 5000); // 成交量
    const amount = +(close * tick_qty).toFixed(2);            // 成交额

    const item = {
      ts_code: stock_code,
      trade_date: date,
      bid_open: open,
      bid_high: high,
      bid_low: low,
      bid_close: close,
      ask_open: +(open + spread).toFixed(5),
      ask_high: +(high + spread).toFixed(5),
      ask_low: +(low + spread).toFixed(5),
      ask_close: +(close + spread).toFixed(5),
      tick_qty,
      amount,
    };

    data.push(item);
    prevClose = close;
    date = addDays(date, 1);
  }

  return { stock_code, data };
}
// ... existing code ...
export const dailyDataPackets = {
  // 如已存在同名键，可合并或覆盖
  'GBPAUD.FXCM': generateDailyPacket('GBPAUD.FXCM', '20240101', 3000, 2.03893),
  'EURUSD.FXCM': generateDailyPacket('EURUSD.FXCM', '20240101', 3000, 1.08350),
  // 可按需继续添加更多代码
};