From f403807f2d5bea5d47b7ab590ed04ad2cd9498ad Mon Sep 17 00:00:00 2001
From: Thomas <4159106+dtslvr@users.noreply.github.com>
Date: Sat, 10 Jul 2021 18:16:46 +0200
Subject: [PATCH] Bugfix/fix average buy price calculation (#204)

* Fix average buy price calculation

* Update changelog
---
 CHANGELOG.md                                  |  1 +
 .../src/app/portfolio/portfolio.service.ts    | 21 ++++++++++---------
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7ff12bfe..4ec4f47a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - Fixed rendering of currency and platform in dialogs (account and transaction)
+- Fixed an issue in the calculation of the average buy prices in the position detail chart
 
 ## 1.24.0 - 07.07.2021
 
diff --git a/apps/api/src/app/portfolio/portfolio.service.ts b/apps/api/src/app/portfolio/portfolio.service.ts
index 71fcadd1..6493bf08 100644
--- a/apps/api/src/app/portfolio/portfolio.service.ts
+++ b/apps/api/src/app/portfolio/portfolio.service.ts
@@ -18,6 +18,7 @@ import { REQUEST } from '@nestjs/core';
 import { DataSource } from '@prisma/client';
 import {
   add,
+  addMonths,
   endOfToday,
   format,
   getDate,
@@ -227,19 +228,18 @@ export class PortfolioService {
       impersonationUserId || this.request.user.id
     );
 
-    const positions = portfolio.getPositions(new Date())[aSymbol];
+    const position = portfolio.getPositions(new Date())[aSymbol];
 
-    if (positions) {
-      let {
+    if (position) {
+      const {
         averagePrice,
         currency,
         firstBuyDate,
         investment,
-        marketPrice,
         quantity,
         transactionCount
-      } = portfolio.getPositions(new Date())[aSymbol];
-
+      } = position;
+      let marketPrice = position.marketPrice;
       const orders = portfolio.getOrders(aSymbol);
 
       const historicalData = await this.dataProviderService.getHistorical(
@@ -267,13 +267,14 @@ export class PortfolioService {
             isSameDay(currentDate, parseISO(orders[0]?.getDate())) ||
             isAfter(currentDate, parseISO(orders[0]?.getDate()))
           ) {
-            // Get snapshot of first day of month
-            const snapshot = portfolio.get(setDate(currentDate, 1))[0]
-              .positions[aSymbol];
+            // Get snapshot of first day of next month
+            const snapshot = portfolio.get(
+              addMonths(setDate(currentDate, 1), 1)
+            )?.[0]?.positions[aSymbol];
             orders.shift();
 
             if (snapshot?.averagePrice) {
-              currentAveragePrice = snapshot?.averagePrice;
+              currentAveragePrice = snapshot.averagePrice;
             }
           }