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

app/api/debug/snapshot/route.ts

@@ -24,6 +24,90 @@ interface RateRecord {
   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 GET(req: Request) {
   const { searchParams } = new URL(req.url);
   const targetDateParam = searchParams.get('date') ?? searchParams.get('targetDate');
@@ -106,79 +190,7 @@ export async function GET(req: Request) {
       assetMap.set(a.id, { symbol: a.symbol, baseCurrency: a.baseCurrency || 'USD' });
     }
 
-    const allRatesHistory = await db
-      .select({
-        fromCurrency: exchangeRatesHistory.fromCurrency,
-        toCurrency: exchangeRatesHistory.toCurrency,
-        rate: exchangeRatesHistory.rate,
-        fetchTime: exchangeRatesHistory.fetchTime,
-      })
-      .from(exchangeRatesHistory)
-      .orderBy(asc(exchangeRatesHistory.fetchTime));
-
-    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, dateStr: string): string | null {
-      const records = ratesCache.get(currencyPair);
-      if (!records || records.length === 0) {
-        return null;
-      }
-      const targetDt = new Date(dateStr + '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 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;
-    }
-
-    function getHistoricalPrice(assetId: string, dateStr: string): string | null {
-      const record = db
-        .select({ price: assetPricesHistory.price })
-        .from(assetPricesHistory)
-        .where(
-          and(
-            eq(assetPricesHistory.assetId, assetId),
-            lte(assetPricesHistory.date, dateStr)
-          )
-        )
-        .orderBy(desc(assetPricesHistory.date))
-        .limit(1);
-      return null;
-    }
+    const dailyRates = await buildDailyRatesMap(targetDateStr);
 
     const details: Array<{
       symbol: string;
@@ -198,26 +210,16 @@ export async function GET(req: Request) {
       const assetInfo = assetMap.get(assetId);
       if (!assetInfo) continue;
 
-      const priceRecord = await db
-        .select({ price: assetPricesHistory.price })
-        .from(assetPricesHistory)
-        .where(
-          and(
-            eq(assetPricesHistory.assetId, assetId),
-            lte(assetPricesHistory.date, targetDateStr)
-          )
-        )
-        .orderBy(desc(assetPricesHistory.date))
-        .limit(1);
+      const costPrice = holding.totalCost.div(holding.quantity).toString();
 
-      const snapshotPrice = priceRecord[0]?.price ?? '0';
+      const snapshotPrice = await getHistoricalPriceWithFallback(assetId, targetDateStr, costPrice);
 
-      const fxRate = getHistoricalRate(assetInfo.baseCurrency, 'CNY', targetDateStr)
-        ?? (assetInfo.baseCurrency === 'CNY' ? '1' : '7.2');
+      const currency = (assetInfo.baseCurrency || 'CNY').toUpperCase();
+      const snapshotFxRate = dailyRates[currency] || dailyRates['USD'] || new Big(1);
 
       const qtyNum = Number(holding.quantity.toString());
       const priceNum = new Big(snapshotPrice);
-      const fxNum = new Big(fxRate);
+      const fxNum = snapshotFxRate;
 
       const calcMarketValueCny = holding.quantity.times(priceNum).times(fxNum);
       const calcCostCny = holding.totalCost.times(fxNum);
@@ -229,7 +231,7 @@ export async function GET(req: Request) {
         symbol: assetInfo.symbol,
         quantity: qtyNum,
         snapshotPrice: new Big(snapshotPrice).toString(),
-        snapshotFxRate: new Big(fxRate).toString(),
+        snapshotFxRate: new Big(fxNum.toString()).toString(),
         calculatedMarketValueCny: calcMarketValueCny.toString(),
         calculatedCostCny: calcCostCny.toString(),
       });