refactor: throw and handle unsufficient funds exception

backend/src/main/java/de/szut/casino/blackjack/BlackJackGameController.java

@@ -1,5 +1,6 @@
 package de.szut.casino.blackjack;
 
+import de.szut.casino.exceptionHandling.exceptions.InsufficientFundsException;
 import de.szut.casino.exceptionHandling.exceptions.UserNotFoundException;
 import de.szut.casino.shared.dto.BetDto;
 import de.szut.casino.shared.service.BalanceService;
@@ -123,7 +124,7 @@ public class BlackJackGameController {
         UserEntity user = optionalUser.get();
 
         if (!this.balanceService.hasFunds(user, betDto)) {
-            return ResponseEntity.badRequest().body(Collections.singletonMap("error", "Insufficient funds"));
+            throw new InsufficientFundsException();
         }
 
         return ResponseEntity.ok(blackJackService.createBlackJackGame(user, betDto.getBetAmount()));

backend/src/main/java/de/szut/casino/exceptionHandling/GlobalExceptionHandler.java

@@ -1,5 +1,6 @@
 package de.szut.casino.exceptionHandling;
 
+import de.szut.casino.exceptionHandling.exceptions.InsufficientFundsException;
 import de.szut.casino.exceptionHandling.exceptions.UserNotFoundException;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
@@ -17,4 +18,10 @@ public class GlobalExceptionHandler {
         ErrorDetails errorDetails = new ErrorDetails(new Date(), ex.getMessage(), request.getDescription(false));
         return new ResponseEntity<>(errorDetails, HttpStatus.NOT_FOUND);
     }
+
+    @ExceptionHandler(InsufficientFundsException.class)
+    public ResponseEntity<?> handleInsufficientFundsException(InsufficientFundsException ex, WebRequest request) {
+        ErrorDetails errorDetails = new ErrorDetails(new Date(), ex.getMessage(), request.getDescription(false));
+        return new ResponseEntity<>(errorDetails, HttpStatus.BAD_REQUEST);
+    }
 }

backend/src/main/java/de/szut/casino/exceptionHandling/exceptions/InsufficientFundsException.java

@@ -0,0 +1,11 @@
+package de.szut.casino.exceptionHandling.exceptions;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.ResponseStatus;
+
+@ResponseStatus(value = HttpStatus.BAD_REQUEST)
+public class InsufficientFundsException extends RuntimeException {
+    public InsufficientFundsException() {
+        super("insufficient funds");
+    }
+}

backend/src/main/java/de/szut/casino/lootboxes/LootBoxController.java

@@ -1,5 +1,6 @@
 package de.szut.casino.lootboxes;
 
+import de.szut.casino.exceptionHandling.exceptions.InsufficientFundsException;
 import de.szut.casino.exceptionHandling.exceptions.UserNotFoundException;
 import de.szut.casino.user.UserEntity;
 import de.szut.casino.user.UserRepository;
@@ -44,9 +45,7 @@ public class LootBoxController {
         UserEntity user = optionalUser.get();
 
         if (lootBoxService.hasSufficientBalance(user, lootBox.getPrice())) {
-            Map<String, String> errorResponse = new HashMap<>();
+            throw new InsufficientFundsException();
-            errorResponse.put("error", "Insufficient balance");
-            return ResponseEntity.badRequest().body(errorResponse);
         }
 
         RewardEntity reward = lootBoxService.determineReward(lootBox);

backend/src/main/java/de/szut/casino/slots/SlotController.java

@@ -1,5 +1,6 @@
 package de.szut.casino.slots;
 
+import de.szut.casino.exceptionHandling.exceptions.InsufficientFundsException;
 import de.szut.casino.exceptionHandling.exceptions.UserNotFoundException;
 import de.szut.casino.shared.dto.BetDto;
 import de.szut.casino.shared.service.BalanceService;
@@ -38,7 +39,7 @@ public class SlotController {
         UserEntity user = optionalUser.get();
 
         if (!this.balanceService.hasFunds(user, betDto)) {
-            return ResponseEntity.badRequest().body(Collections.singletonMap("error", "Insufficient funds"));
+            throw new InsufficientFundsException();
         }
 
         SpinResult spinResult = this.slotService.spin(