Add stop_price_type support (futures only!).

freqtrade/exchange/exchange.py

@@ -23,6 +23,7 @@ from freqtrade.constants import (DEFAULT_AMOUNT_RESERVE_PERCENT, NON_OPEN_EXCHAN
                                  PairWithTimeframe)
 from freqtrade.data.converter import clean_ohlcv_dataframe, ohlcv_to_dataframe, trades_dict_to_list
 from freqtrade.enums import OPTIMIZE_MODES, CandleType, MarginMode, TradingMode
+from freqtrade.enums.pricetype import PriceType
 from freqtrade.exceptions import (DDosProtection, ExchangeError, InsufficientFundsError,
                                   InvalidOrderException, OperationalException, PricingError,
                                   RetryableOrderError, TemporaryError)
@@ -1160,6 +1161,10 @@ class Exchange:
                                            stop_price=stop_price_norm)
             if self.trading_mode == TradingMode.FUTURES:
                 params['reduceOnly'] = True
+                if 'stoploss_price_type' in order_types and 'stop_price_type_field' in self._ft_has:
+                    price_type = self._ft_has['stop_price_type_value_mapping'][
+                        order_types.get('stoploss_price_type', PriceType.LAST)]
+                    params[self._ft_has['stop_price_type_field']] = price_type
 
             amount = self.amount_to_precision(pair, self._amount_to_contracts(pair, amount))