// FRED 發布日程：補足 BLS/BEA 未涵蓋的重要美國總經（零售、房市、ADP、初領失業金等）
const UA = 'finance-dashboard/1.0';
const FRED_RELEASES = [
  { id: 9, title: '零售銷售', impact: 'medium', time: '08:30 美東', note: '全美零售與餐飲銷售，反映內需動能' },
  { id: 13, title: '工業生產 / 產能利用率', impact: 'medium', time: '09:15 美東', note: '工廠產出與產能使用率，景氣先行指標' },
  { id: 91, title: '密西根消費者信心', impact: 'medium', time: '10:00 美東', note: '消費者對景氣與通膨的預期，影響風險偏好' },
  { id: 27, title: '新屋開工 / 營建許可', impact: 'medium', time: '08:30 美東', note: '住宅建築活動，利率敏感指標' },
  { id: 291, title: '成屋銷售', impact: 'medium', time: '10:00 美東', note: '既有住宅成交，觀察房市需求' },
  { id: 95, title: '耐久財 / 工廠接單出貨', impact: 'medium', time: '08:30 美東', note: '企業資本支出與製造需求' },
  { id: 14, title: '消費信貸', impact: 'low', time: '15:00 美東', note: '家庭與信用卡借款，觀察消費支撐' },
  { id: 180, title: '初領失業救濟金', impact: 'medium', time: '08:30 美東', note: '每週勞動市場溫度，突增常引發避險' },
  { id: 194, title: 'ADP 私部門就業', impact: 'medium', time: '08:15 美東', note: '非農公布前的私部門就業參考' },
  { id: 351, title: '費城 Fed 製造業指數', impact: 'medium', time: '08:30 美東', note: '製造業景氣調查，PMI 類指標' },
  { id: 352, title: '非製造業景氣調查', impact: 'medium', time: '10:00 美東', note: '服務業活動，占美國經濟比重大' },
  { id: 219, title: '芝加哥 Fed 全國活動指數', impact: 'low', time: '08:30 美東', note: '綜合 85 項經濟指標的月度摘要' },
  { id: 11, title: '就業成本指數 ECI', impact: 'medium', time: '08:30 美東', note: '薪資與福利成本，Fed 關注的通膨壓力' },
  { id: 16, title: '生產力與單位成本', impact: 'medium', time: '08:30 美東', note: '企業效率與人工成本，影響獲利與通膨' },
];

function getFredKey() {
  const key = process.env.FRED_API_KEY;
  if (!key || key === 'your_fred_api_key_here') return null;
  return key;
}

const sleep = (ms) => new Promise((r) => setTimeout(r, ms));

async function fetchReleaseDates(releaseId, key) {
  const url = `https://api.stlouisfed.org/fred/release/dates?release_id=${releaseId}` +
    `&include_release_dates_with_no_data=true&limit=100&sort_order=desc&api_key=${key}&file_type=json`;
  for (let attempt = 0; attempt < 3; attempt++) {
    const res = await fetch(url, { headers: { 'User-Agent': UA } });
    if (res.status === 429) {
      await sleep(800 * (attempt + 1));
      continue;
    }
    if (!res.ok) throw new Error(`FRED release ${releaseId} HTTP ${res.status}`);
    const data = await res.json();
    return (data.release_dates || []).map((row) => row.date);
  }
  throw new Error(`FRED release ${releaseId} rate limited`);
}

export async function fetchFredMacroEvents(start, end) {
  const key = getFredKey();
  if (!key) return [];
  const events = [];
  for (const rel of FRED_RELEASES) {
    try {
      const dates = await fetchReleaseDates(rel.id, key);
      for (const date of dates) {
        if (date < start || date > end) continue;
        events.push({
          date,
          time: rel.time,
          title: rel.title,
          category: 'macro',
          impact: rel.impact,
          source: 'FRED releases',
          note: rel.note,
        });
      }
    } catch {
      // 單一來源失敗不阻擋整體日曆
    }
    await sleep(300);
  }
  return events;
}