Stage 05.8 - quantity normalization by exchange rules

app/src/trading/orders/service.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from decimal import Decimal, InvalidOperation, ROUND_DOWN
+from decimal import Decimal, InvalidOperation, ROUND_DOWN, ROUND_UP
 
 from src.core.config import load_settings
 from src.integrations.exchange.models import ExchangeSymbol
@@ -181,8 +181,6 @@ class OrderDraftsService:
         return self.repository.get_draft_by_id(draft_id)
 
     def get_entry_context(self, *, side: str, order_type: str) -> OrderEntryContext:
-        # Собираем контекст экрана ввода ордера на основе биржевых правил,
-        # текущего рынка и доступного баланса.
         validation = self.exchange.validate_symbol(self.settings.default_symbol)
         if not validation.is_valid or validation.symbol_info is None:
             raise ValueError(validation.message)
@@ -307,6 +305,103 @@ class OrderDraftsService:
 
         return errors
 
+    def normalize_preset_quantity(
+        self,
+        *,
+        side: str,
+        order_type: str,
+        raw_quantity: str,
+        price: str | None = None,
+    ) -> str | None:
+        return self._normalize_entry_quantity_with_rules(
+            side=side,
+            order_type=order_type,
+            raw_quantity=raw_quantity,
+            price=price,
+            raise_to_minimum=True,
+        )
+
+    def normalize_entry_quantity(
+        self,
+        *,
+        side: str,
+        order_type: str,
+        raw_quantity: str,
+        price: str | None = None,
+    ) -> str | None:
+        return self._normalize_entry_quantity_with_rules(
+            side=side,
+            order_type=order_type,
+            raw_quantity=raw_quantity,
+            price=price,
+            raise_to_minimum=True,
+        )
+
+    def _normalize_entry_quantity_with_rules(
+        self,
+        *,
+        side: str,
+        order_type: str,
+        raw_quantity: str,
+        price: str | None = None,
+        raise_to_minimum: bool,
+    ) -> str | None:
+        validation = self.exchange.validate_symbol(self.settings.default_symbol)
+        if not validation.is_valid or validation.symbol_info is None:
+            return self.normalize_quantity(raw_quantity)
+
+        original_quantity = self._to_decimal((raw_quantity or "").strip().replace(",", "."))
+        if original_quantity is None or original_quantity <= 0:
+            return None
+
+        symbol_info = validation.symbol_info
+        step_size = self._to_decimal(getattr(symbol_info, "step_size", None))
+        min_qty = self._to_decimal(getattr(symbol_info, "min_qty", None))
+        min_notional = self._to_decimal(getattr(symbol_info, "min_notional", None))
+
+        minimum_allowed = min_qty if min_qty is not None and min_qty > 0 else None
+
+        reference_price = self._resolve_reference_price_for_entry(
+            side=side,
+            order_type=order_type,
+            price=price,
+        )
+        if (
+            reference_price is not None
+            and reference_price > 0
+            and min_notional is not None
+            and min_notional > 0
+        ):
+            min_by_notional = min_notional / reference_price
+            if step_size is not None and step_size > 0:
+                min_by_notional = self._ceil_to_step(min_by_notional, step_size)
+
+            if minimum_allowed is None or min_by_notional > minimum_allowed:
+                minimum_allowed = min_by_notional
+
+        quantity = original_quantity
+
+        if step_size is not None and step_size > 0:
+            quantity = self._floor_to_step(quantity, step_size)
+
+        if quantity <= 0:
+            if raise_to_minimum and minimum_allowed is not None and minimum_allowed > 0:
+                quantity = minimum_allowed
+                if step_size is not None and step_size > 0 and not self._fits_step(quantity, step_size):
+                    quantity = self._ceil_to_step(quantity, step_size)
+            else:
+                return None
+
+        if raise_to_minimum and minimum_allowed is not None and quantity < minimum_allowed:
+            quantity = minimum_allowed
+            if step_size is not None and step_size > 0 and not self._fits_step(quantity, step_size):
+                quantity = self._ceil_to_step(quantity, step_size)
+
+        if quantity <= 0:
+            return None
+
+        return self._format_decimal(quantity)
+
     def _build_quantity_presets(
         self,
         *,
@@ -452,6 +547,13 @@ class OrderDraftsService:
         ratio = (value / step).to_integral_value(rounding=ROUND_DOWN)
         return ratio * step
 
+    @staticmethod
+    def _ceil_to_step(value: Decimal, step: Decimal) -> Decimal:
+        if step <= 0:
+            return value
+        ratio = (value / step).to_integral_value(rounding=ROUND_UP)
+        return ratio * step
+
     def _normalize_quantity_to_exchange_rules(
         self,
         *,
@@ -498,7 +600,9 @@ class OrderDraftsService:
         price: str | None = None,
     ) -> Decimal | None:
         if order_type.upper() == "LIMIT":
-            return self._to_decimal(price)
+            explicit_price = self._to_decimal(price)
+            if explicit_price is not None and explicit_price > 0:
+                return explicit_price
 
         try:
             market = self.exchange.get_market_snapshot(self.settings.default_symbol)