// ═══════════════════════════════════════════════════════════
//  fundamentals.js — server 端抓取公司財報（金鑰不外洩、無需付費）
//  主來源：Yahoo quoteSummary（季/年 損益、現金流、資產負債 + 估值）
//  後備：  SEC EDGAR companyfacts（美股，官方、免金鑰）
//  皆正規化成同一形狀供 fincheck.js 使用。
//  沿用 fred.js 的 server 端 fetch + User-Agent 模式。
// ═══════════════════════════════════════════════════════════
const UA = 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124 Safari/537.36';
const SEC_UA = 'EmmyInvestDashboard/1.0 (personal learning tool; contact@example.com)';

async function jget(url, headers = {}, ms = 9000) {
  const ctrl = new AbortController();
  const timer = setTimeout(() => ctrl.abort(), ms);
  try {
    const res = await fetch(url, { headers: { 'User-Agent': UA, ...headers }, signal: ctrl.signal });
    if (!res.ok) throw new Error(`HTTP ${res.status}`);
    return await res.json();
  } finally { clearTimeout(timer); }
}

const num = (x) => (x && typeof x === 'object' && 'raw' in x) ? x.raw : (typeof x === 'number' ? x : null);
// 用結束年月當季標籤（避免不同公司會計年度造成的「第幾季」混淆）
function quarterLabel(endISO) {
  const d = new Date(endISO); if (isNaN(d)) return String(endISO || '');
  return `${d.getUTCFullYear()}/${String(d.getUTCMonth() + 1).padStart(2, '0')}`;
}
const pct = (a, b) => (a != null && b) ? (a / b) * 100 : null;
function enrich(p) {
  p.grossMargin = pct(p.grossProfit, p.revenue);
  p.operatingMargin = pct(p.operatingIncome, p.revenue);
  p.netMargin = pct(p.netIncome, p.revenue);
  return p;
}

// ─── 現價（Yahoo chart v8，免 crumb；query1 失敗改 query2）───
async function getPrice(symbol) {
  for (const host of ['query1', 'query2']) {
    try {
      const d = await jget(`https://${host}.finance.yahoo.com/v8/finance/chart/${encodeURIComponent(symbol)}?range=5d&interval=1d`);
      const r = d?.chart?.result?.[0];
      if (!r) continue;
      let p = r.meta?.regularMarketPrice;
      if (p == null) { const cl = (r.indicators?.quote?.[0]?.close || []).filter(x => x != null); p = cl.length ? cl[cl.length - 1] : null; }
      return { price: p != null ? p : null, name: r.meta?.shortName || r.meta?.longName || null, currency: r.meta?.currency || null };
    } catch { /* try next host */ }
  }
  return { price: null, name: null, currency: null };
}

// ─── Yahoo quoteSummary（需 cookie + crumb）───
let _auth = { cookie: null, crumb: null, at: 0 };
async function yahooAuth() {
  if (_auth.crumb && Date.now() - _auth.at < 3600e3) return _auth;
  const r1 = await fetch('https://fc.yahoo.com/', { headers: { 'User-Agent': UA } }).catch(() => null);
  const cookie = (r1 && (r1.headers.get('set-cookie') || '')).split(';')[0] || '';
  const r2 = await fetch('https://query2.finance.yahoo.com/v1/test/getcrumb', { headers: { 'User-Agent': UA, Cookie: cookie } });
  const crumb = (await r2.text()).trim();
  if (!crumb || crumb.includes('<')) throw new Error('無法取得 Yahoo crumb');
  _auth = { cookie, crumb, at: Date.now() };
  return _auth;
}
async function fetchYahoo(symbol) {
  const { cookie, crumb } = await yahooAuth();
  const mods = [
    'price', 'summaryDetail', 'defaultKeyStatistics', 'financialData',
    'incomeStatementHistory', 'incomeStatementHistoryQuarterly',
    'cashflowStatementHistory', 'cashflowStatementHistoryQuarterly',
    'balanceSheetHistoryQuarterly',
  ].join('%2C');
  const url = `https://query2.finance.yahoo.com/v10/finance/quoteSummary/${encodeURIComponent(symbol)}?modules=${mods}&crumb=${encodeURIComponent(crumb)}`;
  const d = await jget(url, { Cookie: cookie });
  const r = d?.quoteSummary?.result?.[0];
  if (!r) throw new Error('Yahoo 無資料');

  const incQ = r.incomeStatementHistoryQuarterly?.incomeStatementHistory || [];
  const cfQ = r.cashflowStatementHistoryQuarterly?.cashflowStatements || [];
  const incY = r.incomeStatementHistory?.incomeStatementHistory || [];
  const cfY = r.cashflowStatementHistory?.cashflowStatements || [];
  const bsQ = r.balanceSheetHistoryQuarterly?.balanceSheetStatements || [];
  const shares = num(r.defaultKeyStatistics?.sharesOutstanding);

  const cfByDate = {};
  for (const c of cfQ) cfByDate[num(c.endDate)] = c;
  const quarters = incQ.map(s => {
    const end = num(s.endDate);
    const cf = cfByDate[end] || {};
    const netIncome = num(s.netIncome);
    return enrich({
      end: end ? new Date(end * 1000).toISOString().slice(0, 10) : null,
      label: end ? quarterLabel(end * 1000) : '',
      revenue: num(s.totalRevenue),
      grossProfit: num(s.grossProfit),
      operatingIncome: num(s.operatingIncome),
      netIncome,
      eps: (netIncome != null && shares) ? netIncome / shares : null,
      capex: num(cf.capitalExpenditures),
      ocf: num(cf.totalCashFromOperatingActivities),
    });
  });

  const cfYByDate = {};
  for (const c of cfY) cfYByDate[num(c.endDate)] = c;
  const annual = incY.map(s => {
    const end = num(s.endDate);
    const cf = cfYByDate[end] || {};
    return enrich({
      end: end ? new Date(end * 1000).toISOString().slice(0, 10) : null,
      label: end ? String(new Date(end * 1000).getUTCFullYear()) : '',
      revenue: num(s.totalRevenue),
      grossProfit: num(s.grossProfit),
      netIncome: num(s.netIncome),
      capex: num(cf.capitalExpenditures),
      ocf: num(cf.totalCashFromOperatingActivities),
    });
  });

  const bs = bsQ[0] || {};
  const totalAssets = num(bs.totalAssets);
  const totalLiabilities = num(bs.totalLiab);
  const balance = {
    end: num(bs.endDate) ? new Date(num(bs.endDate) * 1000).toISOString().slice(0, 10) : null,
    totalAssets, totalLiabilities,
    cash: num(bs.cash),
    totalDebt: (num(bs.shortLongTermDebt) || 0) + (num(bs.longTermDebt) || 0) || null,
    debtToAssets: pct(totalLiabilities, totalAssets),
  };

  return {
    source: 'Yahoo Finance',
    name: num(r.price?.shortName) || r.price?.shortName || r.price?.longName || symbol,
    currency: r.price?.currency || null,
    peTrailing: num(r.summaryDetail?.trailingPE),
    marketCap: num(r.price?.marketCap),
    quarters, annual, balance,
  };
}

// ─── SEC EDGAR companyfacts（美股後備）───
let _tickerMap = null;
async function tickerToCik(symbol) {
  if (!_tickerMap) {
    const d = await jget('https://www.sec.gov/files/company_tickers.json', { 'User-Agent': SEC_UA });
    _tickerMap = {};
    for (const k of Object.keys(d)) _tickerMap[String(d[k].ticker).toUpperCase()] = { cik: String(d[k].cik_str).padStart(10, '0'), name: d[k].title };
  }
  return _tickerMap[symbol] || null;
}
// 公司常會在不同年度換 XBRL 概念名（如營收 tag 變更），因此把所有候選概念
// 的序列合併成一條時間線，再用 durationSeries / instantLatest 去重取最新。
function mergeUnits(facts, names, unit = 'USD') {
  let out = [];
  for (const n of names) { const u = facts[n]?.units?.[unit]; if (u) out = out.concat(u); }
  return out.length ? out : null;
}
function pickShares(facts, names) {
  let out = [];
  for (const n of names) { const u = facts[n]?.units?.['USD/shares'] || facts[n]?.units?.shares; if (u) out = out.concat(u); }
  return out.length ? out : null;
}
// 取「期間型」概念的最近 N 期（quarterly ≈ 80-100 天 / annual ≈ 350-380 天）
function durationSeries(units, kind) {
  if (!units) return [];
  const lo = kind === 'q' ? 80 : 330, hi = kind === 'q' ? 100 : 380;
  const byEnd = {};
  for (const e of units) {
    if (!e.start || !e.end) continue;
    const days = (new Date(e.end) - new Date(e.start)) / 86400000;
    if (days < lo || days > hi) continue;
    // 同一 end 取較新申報（10-Q/10-K）
    if (!byEnd[e.end] || (e.filed || '') > (byEnd[e.end].filed || '')) byEnd[e.end] = e;
  }
  return Object.values(byEnd).sort((a, b) => (a.end < b.end ? 1 : -1));
}
function instantLatest(units) {
  if (!units) return null;
  const sorted = units.filter(e => e.end).sort((a, b) => (a.end < b.end ? 1 : -1));
  return sorted[0] || null;
}
async function fetchEdgar(symbol) {
  const hit = await tickerToCik(symbol);
  if (!hit) throw new Error('SEC EDGAR 查無此美股代號');
  const cf = await jget(`https://data.sec.gov/api/xbrl/companyfacts/CIK${hit.cik}.json`, { 'User-Agent': SEC_UA });
  const g = cf.facts?.['us-gaap'] || {};
  const REV = ['RevenueFromContractWithCustomerExcludingAssessedTax', 'Revenues', 'RevenueFromContractWithCustomerIncludingAssessedTax', 'SalesRevenueNet', 'SalesRevenueGoodsNet'];
  const revU = mergeUnits(g, REV);
  const gpU = mergeUnits(g, ['GrossProfit']);
  const oiU = mergeUnits(g, ['OperatingIncomeLoss']);
  const niU = mergeUnits(g, ['NetIncomeLoss']);
  const epsU = pickShares(g, ['EarningsPerShareDiluted', 'EarningsPerShareBasic']);
  const capU = mergeUnits(g, ['PaymentsToAcquirePropertyPlantAndEquipment', 'PaymentsToAcquireProductiveAssets']);
  const ocfU = mergeUnits(g, ['NetCashProvidedByUsedInOperatingActivities', 'NetCashProvidedByUsedInOperatingActivitiesContinuingOperations']);

  const mapByEnd = (series) => { const m = {}; for (const e of series) m[e.end] = e.val; return m; };
  const revQ = durationSeries(revU, 'q'), gpQ = durationSeries(gpU, 'q'), oiQ = durationSeries(oiU, 'q'), niQ = durationSeries(niU, 'q'), epsQ = durationSeries(epsU, 'q');
  const gpM = mapByEnd(gpQ), oiM = mapByEnd(oiQ), niM = mapByEnd(niQ), epsM = mapByEnd(epsQ);
  const quarters = revQ.slice(0, 8).map(e => enrich({
    end: e.end, label: quarterLabel(e.end),
    revenue: e.val, grossProfit: gpM[e.end] ?? null, operatingIncome: oiM[e.end] ?? null,
    netIncome: niM[e.end] ?? null, eps: epsM[e.end] ?? null, capex: null, ocf: null,
  }));

  const revY = durationSeries(revU, 'y'), niY = durationSeries(niU, 'y'), capY = durationSeries(capU, 'y'), ocfY = durationSeries(ocfU, 'y'), gpY = durationSeries(gpU, 'y');
  const niYM = mapByEnd(niY), capYM = mapByEnd(capY), ocfYM = mapByEnd(ocfY), gpYM = mapByEnd(gpY);
  const annual = revY.slice(0, 5).map(e => enrich({
    end: e.end, label: String(new Date(e.end).getUTCFullYear()),
    revenue: e.val, grossProfit: gpYM[e.end] ?? null, netIncome: niYM[e.end] ?? null,
    capex: capYM[e.end] != null ? -Math.abs(capYM[e.end]) : null, ocf: ocfYM[e.end] ?? null,
  }));

  const assetsE = instantLatest(mergeUnits(g, ['Assets']));
  const liabE = instantLatest(mergeUnits(g, ['Liabilities']));
  const cashE = instantLatest(mergeUnits(g, ['CashAndCashEquivalentsAtCarryingValue', 'CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents']));
  const balance = {
    end: assetsE?.end || null,
    totalAssets: assetsE?.val ?? null,
    totalLiabilities: liabE?.val ?? null,
    cash: cashE?.val ?? null,
    totalDebt: null,
    debtToAssets: pct(liabE?.val, assetsE?.val),
  };

  if (!quarters.length && !annual.length) throw new Error('EDGAR 無 us-gaap 財報資料（可能為以 IFRS 申報的外國發行人，建議改查其美股同業）');
  return { source: 'SEC EDGAR', name: cf.entityName || hit.name || symbol, currency: 'USD', peTrailing: null, marketCap: null, quarters, annual, balance };
}

// ─── 輕量「是否有新財報」探針（美股；只抓 submissions，比 companyfacts 小很多）───
// 回傳最近一筆財報類申報的識別碼，用來判斷自上次抓取後是否出現新財報。
export async function getLatestFilingInfo(symbol) {
  const hit = await tickerToCik(symbol);
  if (!hit) return null;
  const d = await jget(`https://data.sec.gov/submissions/CIK${hit.cik}.json`, { 'User-Agent': SEC_UA });
  const f = d.filings?.recent;
  if (!f || !Array.isArray(f.form)) return null;
  const FORMS = new Set(['10-Q', '10-K', '20-F', '40-F', '6-K']);
  for (let i = 0; i < f.form.length; i++) {
    if (FORMS.has(f.form[i])) return { accn: f.accessionNumber?.[i] || null, form: f.form[i], filingDate: f.filingDate?.[i] || null };
  }
  return null;
}

// ─── 對外：取得正規化財報（價格 + 兩來源擇優）───
export async function getFundamentals(symbol) {
  const priceInfo = await getPrice(symbol);
  let data = null, errs = [];
  try {
    data = await fetchYahoo(symbol);
    if (!data.quarters?.length && !data.annual?.length) { errs.push('Yahoo 無財報期間'); data = null; }
  } catch (e) { errs.push('Yahoo: ' + (e?.message || e)); }
  if (!data) {
    try { data = await fetchEdgar(symbol); }
    catch (e) { errs.push('EDGAR: ' + (e?.message || e)); }
  }
  if (!data) throw new Error('兩個來源都取不到財報（' + errs.join('；') + '）');

  const asOf = data.quarters?.[0]?.label || data.annual?.[0]?.label || null;
  return {
    symbol,
    name: data.name || priceInfo.name || symbol,
    currency: data.currency || priceInfo.currency || 'USD',
    source: data.source,
    asOf,
    price: priceInfo.price,
    peTrailing: data.peTrailing ?? null,
    marketCap: data.marketCap ?? null,
    quarters: data.quarters || [],
    annual: data.annual || [],
    balance: data.balance || {},
  };
}