From b9e580a82e8bfbe56cd18ada60c5c03e5118a2d4 Mon Sep 17 00:00:00 2001
From: Reto Kaul <retokaul@sublimd.com>
Date: Thu, 17 Feb 2022 13:25:32 +0100
Subject: [PATCH] Improvements

---
 .../app/portfolio/portfolio-calculator-new.ts | 58 +++++++++----------
 1 file changed, 28 insertions(+), 30 deletions(-)

diff --git a/apps/api/src/app/portfolio/portfolio-calculator-new.ts b/apps/api/src/app/portfolio/portfolio-calculator-new.ts
index 38a436bf9..ebc17e18a 100644
--- a/apps/api/src/app/portfolio/portfolio-calculator-new.ts
+++ b/apps/api/src/app/portfolio/portfolio-calculator-new.ts
@@ -272,7 +272,7 @@ export class PortfolioCalculatorNew {
         transactionCount: item.transactionCount
       });
     }
-    const overall = this.calculateOverallPerformance(positions);
+    const overall = this.calculateOverallPerformance(positions, initialValues);
 
     return {
       ...overall,
@@ -393,28 +393,19 @@ export class PortfolioCalculatorNew {
     };
   }
 
-  private calculateOverallPerformance(positions: TimelinePosition[]) {
+  private calculateOverallPerformance(
+    positions: TimelinePosition[],
+    initialValues: { [symbol: string]: Big }
+  ) {
     let currentValue = new Big(0);
     let grossPerformance = new Big(0);
     let grossPerformancePercentage = new Big(0);
     let hasErrors = false;
     let netPerformance = new Big(0);
     let netPerformancePercentage = new Big(0);
-    let totalGrossPerformanceFluctuation = new Big(0);
+    let sumOfWeights = new Big(0);
     let totalInvestment = new Big(0);
 
-    for (const currentPosition of positions) {
-      if (
-        currentPosition.grossPerformance &&
-        currentPosition.grossPerformancePercentage
-      ) {
-        totalGrossPerformanceFluctuation =
-          totalGrossPerformanceFluctuation.plus(
-            currentPosition.grossPerformance.abs()
-          );
-      }
-    }
-
     for (const currentPosition of positions) {
       if (currentPosition.marketPrice) {
         currentValue = currentValue.plus(
@@ -436,20 +427,21 @@ export class PortfolioCalculatorNew {
         hasErrors = true;
       }
 
-      if (
-        currentPosition.grossPerformancePercentage &&
-        !totalGrossPerformanceFluctuation.eq(0)
-      ) {
-        const ratioOfCurrentPosition = currentPosition.grossPerformance
-          .abs()
-          .div(totalGrossPerformanceFluctuation);
+      if (currentPosition.grossPerformancePercentage) {
+        // Use the average from the initial value and the current investment as
+        // a weight
+        const weight = (initialValues[currentPosition.symbol] ?? new Big(0))
+          .plus(currentPosition.investment)
+          .div(2);
+
+        sumOfWeights = sumOfWeights.plus(weight);
 
         grossPerformancePercentage = grossPerformancePercentage.plus(
-          currentPosition.grossPerformancePercentage.mul(ratioOfCurrentPosition)
+          currentPosition.grossPerformancePercentage.mul(weight)
         );
 
         netPerformancePercentage = netPerformancePercentage.plus(
-          currentPosition.netPerformancePercentage.mul(ratioOfCurrentPosition)
+          currentPosition.netPerformancePercentage.mul(weight)
         );
       } else if (!currentPosition.quantity.eq(0)) {
         Logger.warn(
@@ -459,6 +451,9 @@ export class PortfolioCalculatorNew {
       }
     }
 
+    grossPerformancePercentage = grossPerformancePercentage.div(sumOfWeights);
+    netPerformancePercentage = netPerformancePercentage.div(sumOfWeights);
+
     return {
       currentValue,
       grossPerformance,
@@ -743,12 +738,15 @@ export class PortfolioCalculatorNew {
         .mul(order.unitPrice)
         .mul(this.getFactor(order.type));
 
-      if (
-        !initialValue &&
-        order.itemType !== 'start' &&
-        order.itemType !== 'end'
-      ) {
-        initialValue = transactionInvestment;
+      if (i >= indexOfStartOrder && !initialValue) {
+        if (
+          i === indexOfStartOrder &&
+          !valueOfInvestmentBeforeTransaction.eq(0)
+        ) {
+          initialValue = valueOfInvestmentBeforeTransaction;
+        } else if (transactionInvestment.gt(0)) {
+          initialValue = transactionInvestment;
+        }
       }
 
       fees = fees.plus(order.fee);