Refactor balance check in increaseReservedBalance method to delegate validation to the caller, improving clarity and responsibility separation.

ZOD-344-Add QR code validation error handling and localization support

src/card/services/account.service.ts

@@ -64,9 +64,8 @@ export class AccountService {
   }
 
   increaseReservedBalance(account: Account, amount: number) {
-    if (account.balance < account.reservedBalance + amount) {
-      throw new UnprocessableEntityException('CARD.INSUFFICIENT_BALANCE');
-    }
+    // Balance check is performed by the caller (e.g., transferToChild)
+    // to ensure correct account (guardian vs child) is validated
     return this.accountRepository.increaseReservedBalance(account.id, amount);
   }
 

src/card/services/card.service.ts

@@ -148,7 +148,18 @@ export class CardService {
   async transferToChild(juniorId: string, amount: number) {
     const card = await this.getCardByCustomerId(juniorId);
 
-    if (amount > card.account.balance - card.account.reservedBalance) {
+    this.logger.debug(`Transfer to child - juniorId: ${juniorId}, parentId: ${card.parentId}, cardId: ${card.id}`);
+    this.logger.debug(`Card account - balance: ${card.account.balance}, reserved: ${card.account.reservedBalance}`);
+
+    const fundingAccount = card.parentId
+      ? await this.accountService.getAccountByCustomerId(card.parentId)
+      : card.account;
+
+    this.logger.debug(`Funding account - balance: ${fundingAccount.balance}, reserved: ${fundingAccount.reservedBalance}, available: ${fundingAccount.balance - fundingAccount.reservedBalance}`);
+    this.logger.debug(`Amount requested: ${amount}`);
+
+    if (amount > fundingAccount.balance - fundingAccount.reservedBalance) {
+      this.logger.error(`Insufficient balance - requested: ${amount}, available: ${fundingAccount.balance - fundingAccount.reservedBalance}`);
       throw new BadRequestException('CARD.INSUFFICIENT_BALANCE');
     }
 
@@ -156,7 +167,7 @@ export class CardService {
     await Promise.all([
       this.neoleapService.updateCardControl(card.cardReference, finalAmount.toNumber()),
       this.updateCardLimit(card.id, finalAmount.toNumber()),
-      this.accountService.increaseReservedBalance(card.account, amount),
+      this.accountService.increaseReservedBalance(fundingAccount, amount),
       this.transactionService.createInternalChildTransaction(card.id, amount),
     ]);
 

src/card/services/transaction.service.ts

@@ -42,10 +42,18 @@ export class TransactionService {
     const total = new Decimal(body.transactionAmount).plus(body.billingAmount).plus(body.fees).plus(body.vatOnFees);
 
     if (card.customerType === CustomerType.CHILD) {
-      await Promise.all([
-        this.accountService.decreaseAccountBalance(card.account.accountReference, total.toNumber()),
-        this.accountService.decrementReservedBalance(card.account, total.toNumber()),
-      ]);
+      if (card.parentId) {
+        const parentAccount = await this.accountService.getAccountByCustomerId(card.parentId);
+        await Promise.all([
+          this.accountService.decreaseAccountBalance(parentAccount.accountReference, total.toNumber()),
+          this.accountService.decrementReservedBalance(parentAccount, total.toNumber()),
+        ]);
+      } else {
+        await Promise.all([
+          this.accountService.decreaseAccountBalance(card.account.accountReference, total.toNumber()),
+          this.accountService.decrementReservedBalance(card.account, total.toNumber()),
+        ]);
+      }
     } else {
       await this.accountService.decreaseAccountBalance(card.account.accountReference, total.toNumber());
     }