From b65510da4d9c7ec9e8832199a1bb3d0b1302aa7a Mon Sep 17 00:00:00 2001
From: Lel2PouxLait <84011642+Lel2PouxLait@users.noreply.github.com>
Date: Sun, 24 Nov 2024 14:55:49 +0100
Subject: [PATCH] Patch wrong usage of trades fees

Trades fees were added to the portfolio_purchase_price instead of removed which led to an overestimated portfolio_purchase_price.

Easily testable with :

BUY BTC 1 1000 EUR,1000 10
SELL BTC 0.375 1200 EUR 450.0 3
SELL BTC 0.625 2080 EUR 1300 7

Without the patch : [portfolio_purchase_price_net] = 1010

With the patch : [portfolio_purchase_price_net] = 990
---
 coin2086/pnl.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/coin2086/pnl.py b/coin2086/pnl.py
index 26ea129..376aef1 100644
--- a/coin2086/pnl.py
+++ b/coin2086/pnl.py
@@ -10,7 +10,7 @@
 def add_portfolio_purchase_price(trades, initial_purchase_price):
     trades["portfolio_purchase_price"] = 0
     trades.loc[trades["trade_side"] == "BUY", "portfolio_purchase_price"] = (
-        trades["amount"] + trades["fee"]
+        trades["amount"] - trades["fee"]
     )
     trades["portfolio_purchase_price"] = trades["portfolio_purchase_price"].cumsum()
     trades["portfolio_purchase_price"] += initial_purchase_price