feat : Apple Server Notification V2 대응 서버 알림 구현 #327

[essaysir]

작업내용

• https://developer.apple.com/documentation/appstoreservernotifications/app-store-server-notifications-v2
• 애플에서 결제에 관련한 알림을 주인장 서버로 요청 시 대응 컨트롤러 구현

구현 내용

• 환불 구현 내용

@Transactional
	public void handleRefundPurchase(String transactionId) {
		PurchasedPencil pencil = purchasedPencilFinder.findByTransactionId(transactionId)
			.orElseThrow(() -> new EntityNotFoundException("PurchasedPencil not found with transactionId: " + transactionId));

		log.info("Refund processed for transactionId: {}", transactionId);

		pencil.markAsRefund();

		PencilAccount buyerAccount = pencilAccountFinder.findByMemberWithLock(pencil.getMember());
		executeRefund(buyerAccount, pencil.getPurchaseQuantity(), pencil.getPrice());

	}

	public void executeRefund(PencilAccount buyerAccount, long pencilQuantity, long price) {
		long purchasedToUse = Math.min(buyerAccount.getPurchasedBalance(), pencilQuantity);
		buyerAccount.decreasePurchasedBalance(purchasedToUse);

		long remaining = pencilQuantity - purchasedToUse;
		long acquiredToUse = Math.min(buyerAccount.getAcquiredBalance(), remaining);
		buyerAccount.decreaseAcquiredBalance(acquiredToUse);

		buyerAccount.increaseTotalRefundAmount(price);
		// 남은 수량이 0이 아닐 경우 로그 기록
		if (remaining - acquiredToUse > 0) {
			log.warn("Not enough balance to fully refund {} pencils. Refunded only {}.", pencilQuantity, (purchasedToUse + acquiredToUse));
		}
	}