From d0b26963aa9c81c49f7e4a1380e83481315bb158 Mon Sep 17 00:00:00 2001
From: KenTandrian <kenricktan11@gmail.com>
Date: Thu, 11 Sep 2025 23:41:09 +0700
Subject: [PATCH] fix(api): add logic for selling all units

---
 .../app/portfolio/calculator/portfolio-calculator.ts   | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/apps/api/src/app/portfolio/calculator/portfolio-calculator.ts b/apps/api/src/app/portfolio/calculator/portfolio-calculator.ts
index e4d9cdfe8..d3984ad0a 100644
--- a/apps/api/src/app/portfolio/calculator/portfolio-calculator.ts
+++ b/apps/api/src/app/portfolio/calculator/portfolio-calculator.ts
@@ -937,11 +937,19 @@ export abstract class PortfolioCalculator {
             );
           }
         } else if (type === 'SELL') {
-          if (oldAccumulatedSymbol.investment.gt(0)) {
+          if (
+            oldAccumulatedSymbol.quantity.gt(0) &&
+            oldAccumulatedSymbol.quantity.eq(quantity)
+          ) {
+            // Selling all units, so investment should be 0
+            investment = new Big(0);
+          } else if (oldAccumulatedSymbol.investment.gt(0)) {
+            // Selling part of a positive investment
             investment = oldAccumulatedSymbol.investment.minus(
               quantity.mul(oldAccumulatedSymbol.averagePrice)
             );
           } else {
+            // Selling part of a negative investment (short sell)
             investment = oldAccumulatedSymbol.investment.minus(
               quantity.mul(unitPrice)
             );