Stage 05.3 - order validation, error handling and journal logging

app/src/trading/orders/models.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 
 
 @dataclass(slots=True)
@@ -24,4 +24,10 @@ class OrderEntryContext:
     last_price: float
     bid_price: float
     ask_price: float
-    quantity_presets: list[str]
+    quantity_presets: list[str]
+
+
+@dataclass(slots=True)
+class OrderValidationResult:
+    is_valid: bool
+    errors: list[str] = field(default_factory=list)

app/src/trading/orders/service.py

@@ -1,10 +1,12 @@
 from __future__ import annotations
 
+from decimal import Decimal, InvalidOperation
+
 from src.core.config import load_settings
 from src.integrations.exchange.service import ExchangeService
 from src.storage.repositories.order_drafts import OrderDraftRepository
 from src.trading.journal.service import JournalService
-from src.trading.orders.models import OrderDraft, OrderEntryContext
+from src.trading.orders.models import OrderDraft, OrderEntryContext, OrderValidationResult
 
 
 class OrderDraftsService:
@@ -32,6 +34,25 @@ class OrderDraftsService:
         )
 
     def save_draft(self, draft: OrderDraft) -> None:
+        validation = self.validate_draft(draft)
+        if not validation.is_valid:
+            try:
+                self.journal.log_warning(
+                    "order_draft_validation_failed",
+                    "Черновик ордера не прошёл валидацию.",
+                    {
+                        "symbol": draft.symbol,
+                        "side": draft.side,
+                        "order_type": draft.order_type,
+                        "quantity": draft.quantity,
+                        "price": draft.price,
+                        "errors": validation.errors,
+                    },
+                )
+            except Exception:
+                pass
+            raise ValueError("; ".join(validation.errors))
+
         payload = {
             "source": "trade_screen",
             "mode": "draft_only",
@@ -63,6 +84,47 @@ class OrderDraftsService:
         except Exception:
             pass
 
+    def validate_draft(self, draft: OrderDraft) -> OrderValidationResult:
+        errors: list[str] = []
+
+        if draft.side not in {"BUY", "SELL"}:
+            errors.append("Сторона ордера должна быть BUY или SELL.")
+
+        if draft.order_type not in {"MARKET", "LIMIT"}:
+            errors.append("Тип ордера должен быть MARKET или LIMIT.")
+
+        symbol_validation = self.exchange.validate_symbol(draft.symbol)
+        if not symbol_validation.is_valid:
+            errors.append(symbol_validation.message)
+
+        quantity = self._to_decimal(draft.quantity)
+        if quantity is None or quantity <= 0:
+            errors.append("Количество должно быть числом больше нуля.")
+
+        if draft.order_type == "LIMIT":
+            if not draft.price:
+                errors.append("Для LIMIT ордера требуется цена.")
+            else:
+                price = self._to_decimal(draft.price)
+                if price is None or price <= 0:
+                    errors.append("Цена должна быть числом больше нуля.")
+                else:
+                    tick_size = None
+                    if symbol_validation.symbol_info is not None:
+                        tick_size = symbol_validation.symbol_info.tick_size
+
+                    if tick_size is not None and tick_size > 0:
+                        tick = Decimal(str(tick_size))
+                        if not self._fits_step(price, tick):
+                            errors.append(
+                                f"Цена должна соответствовать шагу tickSize = {tick_size}."
+                            )
+
+        return OrderValidationResult(
+            is_valid=len(errors) == 0,
+            errors=errors,
+        )
+
     def list_recent_drafts(self, limit: int = 5) -> list[dict[str, str]]:
         return self.repository.list_recent_drafts(limit=limit)
 
@@ -160,4 +222,20 @@ class OrderDraftsService:
     def _format_number(value: float) -> str:
         text = f"{value:.8f}"
         text = text.rstrip("0").rstrip(".")
-        return text or "0"
+        return text or "0"
+
+    @staticmethod
+    def _to_decimal(value: str | None) -> Decimal | None:
+        if value is None:
+            return None
+        try:
+            return Decimal(str(value).strip())
+        except (InvalidOperation, ValueError):
+            return None
+
+    @staticmethod
+    def _fits_step(value: Decimal, step: Decimal) -> bool:
+        if step <= 0:
+            return True
+        ratio = value / step
+        return ratio == ratio.to_integral_value()