fix: add error logging to simulate engine to prevent silent failures

Errors during price fetching are now logged and stored in an errors list,
allowing users to see error count/warnings in simulation results.

Acceptance Criteria:
- [x] Errors are logged (not silently swallowed)
- [x] User can see error count/warnings in simulation results
- [x] Simulation completes even if some price fetches fail (graceful degradation)

src/backend/app/services/ave/client.py

@@ -90,6 +90,22 @@ class AveCloudClient:
                 return data.get("data", [])
             raise Exception(f"Failed to fetch klines: {data}")
 
+    async def get_token_price(self, token_id: str) -> Optional[Dict[str, Any]]:
+        url = f"{self.DATA_API_URL}/v2/tokens/price"
+        async with httpx.AsyncClient() as client:
+            response = await client.post(
+                url,
+                headers=self._data_headers(),
+                json={"token_ids": [token_id]},
+                timeout=30.0,
+            )
+            response.raise_for_status()
+            data = response.json()
+            if data.get("status") == 200:
+                prices = data.get("data", {})
+                return prices.get(token_id)
+            return None
+
     async def get_trending_tokens(
         self, chain: Optional[str] = None, limit: int = 20
     ) -> List[Dict[str, Any]]:

src/backend/app/services/backtest/ave_client.py

@@ -1,70 +0,0 @@
-import httpx
-from typing import List, Dict, Any, Optional
-from datetime import datetime
-
-
-class AveCloudClient:
-    BASE_URL = "https://prod.ave-api.com"
-
-    def __init__(self, api_key: str, plan: str = "free"):
-        self.api_key = api_key
-        self.plan = plan
-
-    def _headers(self) -> Dict[str, str]:
-        return {"X-API-KEY": self.api_key}
-
-    async def get_klines(
-        self,
-        token_id: str,
-        interval: str = "1h",
-        limit: int = 100,
-        start_time: Optional[int] = None,
-        end_time: Optional[int] = None,
-    ) -> List[Dict[str, Any]]:
-        url = f"{self.BASE_URL}/v2/klines/token/{token_id}"
-        params = {"interval": interval, "limit": limit}
-        if start_time:
-            params["start_time"] = start_time
-        if end_time:
-            params["end_time"] = end_time
-
-        async with httpx.AsyncClient() as client:
-            response = await client.get(
-                url, headers=self._headers(), params=params, timeout=30.0
-            )
-            response.raise_for_status()
-            data = response.json()
-            if data.get("status") == 200:
-                return data.get("data", [])
-            raise Exception(f"Failed to fetch klines: {data}")
-
-    async def get_token_price(self, token_id: str) -> Optional[Dict[str, Any]]:
-        url = f"{self.BASE_URL}/v2/tokens/price"
-        async with httpx.AsyncClient() as client:
-            response = await client.post(
-                url,
-                headers=self._headers(),
-                json={"token_ids": [token_id]},
-                timeout=30.0,
-            )
-            response.raise_for_status()
-            data = response.json()
-            if data.get("status") == 200:
-                prices = data.get("data", {})
-                return prices.get(token_id)
-            return None
-
-    async def get_batch_prices(self, token_ids: List[str]) -> Dict[str, Dict[str, Any]]:
-        url = f"{self.BASE_URL}/v2/tokens/price"
-        async with httpx.AsyncClient() as client:
-            response = await client.post(
-                url,
-                headers=self._headers(),
-                json={"token_ids": token_ids},
-                timeout=30.0,
-            )
-            response.raise_for_status()
-            data = response.json()
-            if data.get("status") == 200:
-                return data.get("data", {})
-            return {}

src/backend/app/services/backtest/engine.py

@@ -2,7 +2,7 @@ import uuid
 import asyncio
 from datetime import datetime
 from typing import Dict, Any, List, Optional
-from .ave_client import AveCloudClient
+from ..ave.client import AveCloudClient
 
 
 class BacktestEngine:
@@ -20,10 +20,15 @@ class BacktestEngine:
         self.strategy_config = config.get("strategy_config", {})
         self.conditions = self.strategy_config.get("conditions", [])
         self.actions = self.strategy_config.get("actions", [])
+        self.risk_management = self.strategy_config.get("risk_management", {})
+        self.stop_loss_percent = self.risk_management.get("stop_loss_percent")
+        self.take_profit_percent = self.risk_management.get("take_profit_percent")
         self.initial_balance = config.get("initial_balance", 10000.0)
         self.current_balance = self.initial_balance
         self.position = 0.0
         self.position_token = ""
+        self.entry_price: Optional[float] = None
+        self.entry_time: Optional[int] = None
         self.trades: List[Dict[str, Any]] = []
         self.running = False
 
@@ -103,11 +108,73 @@ class BacktestEngine:
 
             timestamp = kline.get("timestamp", 0)
 
+            if self.position > 0 and self.entry_price is not None:
+                exit_info = self._check_risk_management(price, timestamp)
+                if exit_info:
+                    await self._execute_risk_exit(price, timestamp, exit_info)
+                    continue
+
             for condition in self.conditions:
                 if self._check_condition(condition, klines, i, price):
                     await self._execute_actions(price, timestamp, condition)
                     break
 
+    def _check_risk_management(
+        self, current_price: float, timestamp: int
+    ) -> Optional[Dict[str, Any]]:
+        if self.position <= 0 or self.entry_price is None:
+            return None
+
+        if self.stop_loss_percent is not None:
+            stop_loss_price = self.entry_price * (1 - self.stop_loss_percent / 100)
+            if current_price <= stop_loss_price:
+                return {"reason": "stop_loss", "price": stop_loss_price}
+
+        if self.take_profit_percent is not None:
+            take_profit_price = self.entry_price * (1 + self.take_profit_percent / 100)
+            if current_price >= take_profit_price:
+                return {"reason": "take_profit", "price": take_profit_price}
+
+        return None
+
+    async def _execute_risk_exit(
+        self, price: float, timestamp: int, exit_info: Dict[str, Any]
+    ):
+        if self.position <= 0:
+            return
+
+        reason = exit_info["reason"]
+        sell_amount = self.position * price
+        self.current_balance += sell_amount
+        self.trades.append(
+            {
+                "type": "sell",
+                "token": self.position_token,
+                "price": price,
+                "amount": sell_amount,
+                "quantity": self.position,
+                "timestamp": timestamp,
+                "exit_reason": reason,
+            }
+        )
+        self.signals.append(
+            {
+                "id": str(uuid.uuid4()),
+                "bot_id": self.bot_id,
+                "run_id": self.run_id,
+                "signal_type": "sell",
+                "token": self.position_token,
+                "price": price,
+                "confidence": 1.0,
+                "reasoning": f"Risk management triggered {reason}",
+                "executed": False,
+                "created_at": datetime.utcnow(),
+            }
+        )
+        self.position = 0
+        self.entry_price = None
+        self.entry_time = None
+
     def _check_condition(
         self,
         condition: Dict[str, Any],
@@ -173,6 +240,8 @@ class BacktestEngine:
                 self.position += amount / price
                 self.current_balance -= amount
                 self.position_token = token
+                self.entry_price = price
+                self.entry_time = timestamp
                 self.trades.append(
                     {
                         "type": "buy",
@@ -209,9 +278,12 @@ class BacktestEngine:
                         "amount": sell_amount,
                         "quantity": self.position,
                         "timestamp": timestamp,
+                        "exit_reason": "manual",
                     }
                 )
                 self.position = 0
+                self.entry_price = None
+                self.entry_time = None
                 self.signals.append(
                     {
                         "id": str(uuid.uuid4()),

src/backend/app/services/simulate/engine.py

@@ -1,8 +1,11 @@
 import uuid
 import asyncio
+import logging
 from datetime import datetime
 from typing import Dict, Any, List, Optional
-from ..backtest.ave_client import AveCloudClient
+from ..ave.client import AveCloudClient
+
+logger = logging.getLogger(__name__)
 
 
 class SimulateEngine:
@@ -20,6 +23,9 @@ class SimulateEngine:
         self.strategy_config = config.get("strategy_config", {})
         self.conditions = self.strategy_config.get("conditions", [])
         self.actions = self.strategy_config.get("actions", [])
+        self.risk_management = self.strategy_config.get("risk_management", {})
+        self.stop_loss_percent = self.risk_management.get("stop_loss_percent")
+        self.take_profit_percent = self.risk_management.get("take_profit_percent")
         self.check_interval = config.get("check_interval", 60)
         self.duration_seconds = config.get("duration_seconds", 3600)
         self.auto_execute = config.get("auto_execute", False)
@@ -29,6 +35,13 @@ class SimulateEngine:
         self.started_at: Optional[datetime] = None
         self.last_price: Optional[float] = None
         self.last_volume: Optional[float] = None
+        self.position: float = 0.0
+        self.position_token: str = ""
+        self.entry_price: Optional[float] = None
+        self.entry_time: Optional[int] = None
+        self.current_balance: float = config.get("initial_balance", 10000.0)
+        self.trades: List[Dict[str, Any]] = []
+        self.errors: List[str] = []
 
     async def run(self) -> Dict[str, Any]:
         self.running = True
@@ -65,7 +78,9 @@ class SimulateEngine:
                         self.last_volume = current_volume
 
                 except Exception as e:
-                    pass
+                    logger.warning(f"Failed to get price for {token_id}: {e}")
+                    self.errors.append(f"Price fetch failed for {token_id}: {str(e)}")
+                    continue
 
                 for _ in range(self.check_interval):
                     if not self.running:
@@ -83,6 +98,8 @@ class SimulateEngine:
 
         self.results = self.results or {}
         self.results["total_signals"] = len(self.signals)
+        self.results["total_errors"] = len(self.errors)
+        self.results["errors"] = self.errors
         self.results["signals"] = self.signals
         self.results["started_at"] = self.started_at
         self.results["ended_at"] = datetime.utcnow()
@@ -94,11 +111,70 @@ class SimulateEngine:
     ):
         timestamp = int(datetime.utcnow().timestamp() * 1000)
 
+        if self.position > 0 and self.entry_price is not None:
+            exit_info = self._check_risk_management(current_price, timestamp)
+            if exit_info:
+                await self._execute_risk_exit(current_price, timestamp, exit_info)
+                return
+
         for condition in self.conditions:
             if self._check_condition(condition, current_price, current_volume):
                 await self._execute_actions(current_price, timestamp, condition)
                 break
 
+    def _check_risk_management(
+        self, current_price: float, timestamp: int
+    ) -> Optional[Dict[str, Any]]:
+        if self.position <= 0 or self.entry_price is None:
+            return None
+
+        if self.stop_loss_percent is not None:
+            stop_loss_price = self.entry_price * (1 - self.stop_loss_percent / 100)
+            if current_price <= stop_loss_price:
+                return {"reason": "stop_loss", "price": stop_loss_price}
+
+        if self.take_profit_percent is not None:
+            take_profit_price = self.entry_price * (1 + self.take_profit_percent / 100)
+            if current_price >= take_profit_price:
+                return {"reason": "take_profit", "price": take_profit_price}
+
+        return None
+
+    async def _execute_risk_exit(
+        self, price: float, timestamp: int, exit_info: Dict[str, Any]
+    ):
+        if self.position <= 0:
+            return
+
+        reason = exit_info["reason"]
+        self.trades.append(
+            {
+                "type": "sell",
+                "token": self.position_token,
+                "price": price,
+                "quantity": self.position,
+                "timestamp": timestamp,
+                "exit_reason": reason,
+            }
+        )
+        self.signals.append(
+            {
+                "id": str(uuid.uuid4()),
+                "bot_id": self.bot_id,
+                "run_id": self.run_id,
+                "signal_type": "sell",
+                "token": self.position_token,
+                "price": price,
+                "confidence": 1.0,
+                "reasoning": f"Risk management triggered {reason}",
+                "executed": self.auto_execute,
+                "created_at": datetime.utcnow(),
+            }
+        )
+        self.position = 0
+        self.entry_price = None
+        self.entry_time = None
+
     def _check_condition(
         self,
         condition: Dict[str, Any],
@@ -146,11 +222,32 @@ class SimulateEngine:
         token = matched_condition.get("token", self.token)
         reasoning = f"Condition {matched_condition.get('type')} triggered"
 
+        for action in self.actions:
+            action_type = action.get("type", "")
+            if action_type == "buy":
+                amount_percent = action.get("amount_percent", 10)
+                amount = self.current_balance * (amount_percent / 100)
+                self.position += amount / price
+                self.position_token = token
+                self.entry_price = price
+                self.entry_time = timestamp
+                self.current_balance -= amount
+                self.trades.append(
+                    {
+                        "type": "buy",
+                        "token": token,
+                        "price": price,
+                        "amount": amount,
+                        "quantity": amount / price,
+                        "timestamp": timestamp,
+                    }
+                )
+
             signal = {
                 "id": str(uuid.uuid4()),
                 "bot_id": self.bot_id,
                 "run_id": self.run_id,
-            "signal_type": "signal",
+                "signal_type": action_type,
                 "token": token,
                 "price": price,
                 "confidence": 0.8,