Created interest function

freqtrade/persistence/models.py

@@ -563,6 +563,42 @@ class LocalTrade():
         """
         self.open_trade_value = self._calc_open_trade_value()
 
+    def calculate_interest(self) -> Decimal:
+        # TODO-mg: Need to set other conditions because sometimes self.open_date is not defined, but why would it ever not be set
+        if not self.interest_rate or not (self.borrowed):
+            return Decimal(0.0)
+
+        try:
+            open_date = self.open_date.replace(tzinfo=None)
+            now = datetime.now()
+            secPerDay = 86400
+            days = Decimal((now - open_date).total_seconds()/secPerDay) or 0.0
+            hours = days/24
+        except:
+            raise OperationalException("Time isn't calculated properly")
+
+        rate = Decimal(self.interest_rate)
+        borrowed = Decimal(self.borrowed)
+
+        if self.exchange == 'binance':
+            # Rate is per day but accrued hourly or something
+            # binance: https://www.binance.com/en-AU/support/faq/360030157812
+            return borrowed * (rate/24) * max(hours, 1.0)  # TODO-mg: Is hours rounded?
+        elif self.exchange == 'kraken':
+            # https://support.kraken.com/hc/en-us/articles/206161568-What-are-the-fees-for-margin-trading-
+            opening_fee = borrowed * rate
+            roll_over_fee = borrowed * rate * max(0, (hours-4)/4)
+            return opening_fee + roll_over_fee
+        elif self.exchange == 'binance_usdm_futures':
+            # ! TODO-mg: This is incorrect, I didn't look it up
+            return borrowed * (rate/24) * max(hours, 1.0)
+        elif self.exchange == 'binance_coinm_futures':
+            # ! TODO-mg: This is incorrect, I didn't look it up
+            return borrowed * (rate/24) * max(hours, 1.0)
+        else:
+            # TODO-mg: make sure this breaks and can't be squelched
+            raise OperationalException("Leverage not available on this exchange")
+
     def calc_close_trade_value(self, rate: Optional[float] = None,
                                fee: Optional[float] = None) -> float:
         """
@@ -578,17 +614,7 @@ class LocalTrade():
 
         close_trade = Decimal(self.amount) * Decimal(rate or self.close_rate)  # type: ignore
         fees = close_trade * Decimal(fee or self.fee_close)
-
-        # TODO: Need to set other conditions because sometimes self.open_date is not defined, but why would it ever not be set
-        try:
-            open = self.open_date.replace(tzinfo=None)
-            now = datetime.now()
-
-            # breakpoint()
-            interest = ((Decimal(self.interest_rate or 0) * Decimal(self.borrowed or 0)) *
-                        Decimal((now - open).total_seconds())/86400) or 0  # Interest/day * (seconds in trade)/(seconds per day)
-        except:
-            interest = 0
+        interest = self.calculate_interest()
 
         if (self.is_short):
             return float(close_trade + fees + interest)