From c83a54d20e91b6fb425761a3337872ba5dea38ef Mon Sep 17 00:00:00 2001
From: Thomas <4159106+dtslvr@users.noreply.github.com>
Date: Sun, 12 Mar 2023 11:25:16 +0100
Subject: [PATCH] Calculate exchange rate indirectly via base currency

---
 .../services/exchange-rate-data.service.ts    | 25 +++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/apps/api/src/services/exchange-rate-data.service.ts b/apps/api/src/services/exchange-rate-data.service.ts
index 080772eb9..78c5fdda5 100644
--- a/apps/api/src/services/exchange-rate-data.service.ts
+++ b/apps/api/src/services/exchange-rate-data.service.ts
@@ -183,8 +183,29 @@ export class ExchangeRateDataService {
       if (marketData?.marketPrice) {
         factor = marketData?.marketPrice;
       } else {
-        // TODO: Get from data provider service or calculate indirectly via base currency
-        // and market data
+        // Calculate indirectly via base currency
+        try {
+          const [
+            { marketPrice: marketPriceBaseCurrencyFromCurrency },
+            { marketPrice: marketPriceBaseCurrencyToCurrency }
+          ] = await Promise.all([
+            this.marketDataService.get({
+              dataSource,
+              symbol: `${this.baseCurrency}${aFromCurrency}`,
+              date: aDate
+            }),
+            this.marketDataService.get({
+              dataSource,
+              symbol: `${this.baseCurrency}${aToCurrency}`,
+              date: aDate
+            })
+          ]);
+
+          // Calculate the opposite direction
+          factor =
+            (1 / marketPriceBaseCurrencyFromCurrency) *
+            marketPriceBaseCurrencyToCurrency;
+        } catch {}
       }
     }