Fix close position

src/Managing.Application/Trading/Handlers/CloseSpotPositionCommandHandler.cs

@@ -23,6 +23,7 @@ public class CloseSpotPositionCommandHandler(
         {
             // For backtest, use execution price directly
             var lastPrice = request.ExecutionPrice.GetValueOrDefault();
+            var amountToSwap = request.Position.Open.Quantity;
 
             // Calculate closing direction (opposite of opening direction)
             var direction = request.Position.OriginDirection == TradeDirection.Long
@@ -47,12 +48,21 @@ public class CloseSpotPositionCommandHandler(
             {
                 // For live trading, call SwapGmxTokensAsync
                 var account = await accountService.GetAccountById(request.AccountId);
+                var tokenBalance = await exchangeService.GetBalance(account, request.Position.Ticker);
+
+                if (tokenBalance == null || tokenBalance.Amount <= 0)
+                {
+                    throw new InvalidOperationException(
+                        $"No available balance to close spot position for {request.Position.Ticker}");
+                }
+
+                amountToSwap = tokenBalance.Amount;
                 swapResult = await tradingService.SwapGmxTokensAsync(
                     request.Position.User,
                     account.Name,
                     request.Position.Ticker,
                     Ticker.USDC,
-                    (double)request.Position.Open.Quantity,
+                    (double)amountToSwap,
                     "market",
                     null,
                     0.5);
@@ -68,7 +78,7 @@ public class CloseSpotPositionCommandHandler(
             var closedTrade = exchangeService.BuildEmptyTrade(
                 request.Position.Open.Ticker,
                 lastPrice,
-                request.Position.Open.Quantity,
+                amountToSwap,
                 direction,
                 1, // Spot trading has no leverage
                 TradeType.Market,