fix(ledger): 修复时光机历史汇率串用问题，实装价格向后穿透与成本兜底引擎

src/actions/snapshots.ts

@@ -213,6 +213,95 @@ export async function getEffectivePrice(
   return record?.price ?? null;
 }
 
+interface RateRecord {
+  rate: string;
+  fetchTime: Date;
+}
+
+async function buildDailyRatesMap(targetDateStr: string): Promise<Record<string, Big>> {
+  const allRates = await db
+    .select({
+      fromCurrency: exchangeRatesHistory.fromCurrency,
+      toCurrency: exchangeRatesHistory.toCurrency,
+      rate: exchangeRatesHistory.rate,
+      fetchTime: exchangeRatesHistory.fetchTime,
+    })
+    .from(exchangeRatesHistory)
+    .where(lte(exchangeRatesHistory.fetchTime, new Date(targetDateStr + 'T23:59:59')))
+    .orderBy(asc(exchangeRatesHistory.fetchTime));
+
+  const ratesCache = new Map<string, RateRecord[]>();
+  for (const rec of allRates) {
+    const key = `${rec.fromCurrency}_${rec.toCurrency}`;
+    if (!ratesCache.has(key)) {
+      ratesCache.set(key, []);
+    }
+    ratesCache.get(key)!.push({ rate: rec.rate, fetchTime: rec.fetchTime });
+  }
+
+  function getClosestRateForDate(currencyPair: string): string | null {
+    const records = ratesCache.get(currencyPair);
+    if (!records || records.length === 0) return null;
+    const targetDt = new Date(targetDateStr + 'T00:00:00Z');
+    let closest: RateRecord | null = null;
+    for (const rec of records) {
+      if (rec.fetchTime <= targetDt) {
+        closest = rec;
+      } else {
+        break;
+      }
+    }
+    return closest?.rate ?? null;
+  }
+
+  function resolveRate(from: string, to: string): string | null {
+    const directKey = `${from}_${to}`;
+    const directRate = getClosestRateForDate(directKey);
+    if (directRate) return directRate;
+
+    const usdKey = `USD_${to}`;
+    const usdRate = getClosestRateForDate(usdKey);
+    if (!usdRate) return null;
+    if (from === 'USD') return usdRate;
+
+    const fromToUsdKey = `${from}_USD`;
+    const fromToUsdRate = getClosestRateForDate(fromToUsdKey);
+    if (fromToUsdRate) {
+      return new Big(fromToUsdRate).times(new Big(usdRate)).toString();
+    }
+    return null;
+  }
+
+  const hkdRate = resolveRate('HKD', 'CNY');
+  const usdRate = resolveRate('USD', 'CNY');
+
+  return {
+    USD: new Big(usdRate || '7.22'),
+    HKD: new Big(hkdRate || '0.92'),
+    CNY: new Big(1),
+  };
+}
+
+async function getHistoricalPriceWithFallback(assetId: string, dateStr: string, fallbackCostPrice: string): Promise<string> {
+  const [record] = await db
+    .select({ price: assetPricesHistory.price })
+    .from(assetPricesHistory)
+    .where(
+      and(
+        eq(assetPricesHistory.assetId, assetId),
+        lte(assetPricesHistory.date, dateStr)
+      )
+    )
+    .orderBy(desc(assetPricesHistory.date))
+    .limit(1);
+
+  if (record?.price) {
+    return record.price;
+  }
+
+  return fallbackCostPrice;
+}
+
 export async function reconstructPortfolioHistory() {
   const [earliest] = await db
     .select({ executedAt: transactions.executedAt })
@@ -242,85 +331,11 @@ export async function reconstructPortfolioHistory() {
     .select({
       id: assets.id,
       baseCurrency: assets.baseCurrency,
-      latestPrice: assets.latestPrice,
     })
     .from(assets);
   const assetBaseCurrencyMap = new Map<string, string>();
-  const assetLatestPriceMap = new Map<string, string>();
   for (const a of allAssets) {
     assetBaseCurrencyMap.set(a.id, a.baseCurrency);
-    assetLatestPriceMap.set(a.id, a.latestPrice || '0');
-  }
-
-  const allRatesHistory = await db
-    .select({
-      fromCurrency: exchangeRatesHistory.fromCurrency,
-      toCurrency: exchangeRatesHistory.toCurrency,
-      rate: exchangeRatesHistory.rate,
-      fetchTime: exchangeRatesHistory.fetchTime,
-    })
-    .from(exchangeRatesHistory)
-    .orderBy(asc(exchangeRatesHistory.fetchTime));
-
-  // 构建汇率缓存：按 (fromCurrency, toCurrency) 分组，fetchTime 已升序排列
-  interface RateRecord {
-    rate: string;
-    fetchTime: Date;
-  }
-  const ratesCache = new Map<string, RateRecord[]>();
-
-  for (const rec of allRatesHistory) {
-    const key = `${rec.fromCurrency}_${rec.toCurrency}`;
-    if (!ratesCache.has(key)) {
-      ratesCache.set(key, []);
-    }
-    ratesCache.get(key)!.push({
-      rate: rec.rate,
-      fetchTime: rec.fetchTime,
-    });
-  }
-
-  function getClosestRateForDate(
-    currencyPair: string,
-    targetDateStr: string
-  ): string | null {
-    const records = ratesCache.get(currencyPair);
-    if (!records || records.length === 0) {
-      return null;
-    }
-
-    const targetDate = new Date(targetDateStr + 'T00:00:00Z');
-    let closest: RateRecord | null = null;
-
-    for (const rec of records) {
-      if (rec.fetchTime <= targetDate) {
-        closest = rec;
-      } else {
-        break;
-      }
-    }
-
-    return closest?.rate ?? null;
-  }
-
-  function getHistoricalRate(from: string, to: string, dateStr: string): string | null {
-    const directKey = `${from}_${to}`;
-    const directRate = getClosestRateForDate(directKey, dateStr);
-    if (directRate) return directRate;
-
-    const usdKey = `USD_${to}`;
-    const usdRate = getClosestRateForDate(usdKey, dateStr);
-    if (!usdRate) return null;
-
-    if (from === 'USD') return usdRate;
-
-    const fromToUsdKey = `${from}_USD`;
-    const fromToUsdRate = getClosestRateForDate(fromToUsdKey, dateStr);
-    if (fromToUsdRate) {
-      return new Big(fromToUsdRate).times(new Big(usdRate)).toString();
-    }
-
-    return null;
   }
 
   await db.delete(portfolioSnapshots);
@@ -346,6 +361,8 @@ export async function reconstructPortfolioHistory() {
     let totalValueCny = new Big('0');
     let totalCostCny = new Big('0');
 
+    const dailyRates = await buildDailyRatesMap(dateStr);
+
     const uniqueAssetIds = [...new Set(historicalTx.filter(t =>
       t.txType === 'BUY' || t.txType === 'SELL' || t.txType === 'DIVIDEND'
     ).map(t => t.assetId))];
@@ -361,23 +378,26 @@ export async function reconstructPortfolioHistory() {
           fee: t.fee.toString(),
         }));
 
-      const priceStr = await getEffectivePrice(assetId, currentDate);
       const baseCurrency = assetBaseCurrencyMap.get(assetId) || 'USD';
 
-      const priceStrForMetrics = priceStr || assetLatestPriceMap.get(assetId) || '0';
+      const costPrice = new Big(assetTxs.reduce((sum, t) => {
+        if (t.txType === 'BUY') return sum.plus(new Big(t.price).times(new Big(t.quantity)));
+        if (t.txType === 'SELL') return sum.minus(new Big(t.price).times(new Big(t.quantity)));
+        return sum;
+      }, new Big('0')).div(new Big(assetTxs.reduce((s, t) => t.txType === 'BUY' ? s.plus(t.quantity) : s, new Big('0'))).gt(0) ? new Big(assetTxs.reduce((s, t) => t.txType === 'BUY' ? s.plus(t.quantity) : s, new Big('0'))).toString() : '1')).toString();
 
+      const snapshotPrice = await getHistoricalPriceWithFallback(assetId, dateStr, costPrice);
+
+      const currency = (baseCurrency || 'CNY').toUpperCase();
+      const snapshotFxRate = dailyRates[currency] || dailyRates['USD'] || new Big(1);
+
+      const priceStrForMetrics = snapshotPrice;
       const metrics = calculateAssetMetrics(assetTxs, priceStrForMetrics);
 
-      // 使用历史汇率就近匹配策略获取当日汇率
-      const assetFxRate = new Big(getHistoricalRate(baseCurrency, 'CNY', dateStr) || '1');
-
-      // 市值和本金双双乘以历史汇率
-      const posValueCny = new Big(metrics.marketValue).times(assetFxRate);
-
-      // 投入本金 = (市值 - 累计盈亏) * 历史汇率，确保逻辑自洽
+      const posValueCny = new Big(metrics.marketValue).times(snapshotFxRate);
       const posCostCny = new Big(metrics.marketValue)
                           .minus(metrics.accumulatedPnl)
-                          .times(assetFxRate);
+                          .times(snapshotFxRate);
 
       totalValueCny = totalValueCny.plus(posValueCny);
       totalCostCny = totalCostCny.plus(posCostCny);