@@ -0,0 +1,100 @@
+package store.util;
+
+import static store.constant.AnswerConstant.*;
+import static store.constant.message.ErrorMessage.NON_EXIST_PRODUCT;
+import static store.constant.promotion.PromotionType.CARBONATE_DRINK;
+
+import camp.nextstep.edu.missionutils.DateTimes;
+import store.model.domain.customer.Customer;
+import store.model.domain.product.Product;
+import store.model.domain.product.Products;
+import store.model.domain.product.Promotion;
+import store.model.domain.product.Promotions;
+import store.view.InputView;
+import store.view.OutputView;
+
+public class PromotionHandler {
+
+	public static void handlePromotionMessages(Customer customer, Products products, Promotions promotions) {
+		customer.getBuyingProduct().forEach((productName, quantity) -> {
+			handleSingleProductPromotion(customer, products, promotions, productName, quantity);
+		});
+	}
+
+	private static void handleSingleProductPromotion(Customer customer, Products products, Promotions promotions,
+		String productName, int quantity) {
+		Product product = products.findProductByName(productName);
+		Promotion promotion = findPromotion(promotions, product);
+
+		if (promotion != null && promotion.isApplyPromotion(quantity, DateTimes.now())) {
+			processPromotion(customer, product, quantity, promotion);
+		}
+	}
+
+	private static Promotion findPromotion(Promotions promotions, Product product) {
+		if (product == null) {
+			throw new IllegalArgumentException(NON_EXIST_PRODUCT.getMessage());
+		}
+		return promotions.findPromotionByName(product.getPromotion());
+	}
+
+	private static void processPromotion(Customer customer, Product product, int quantity, Promotion promotion) {
+		if (CARBONATE_DRINK.getPromotionName().equals(promotion.getName())) {
+			handleCarbonatePromotion(customer, product, quantity, promotion);
+		}
+		if (!CARBONATE_DRINK.getPromotionName().equals(promotion.getName())) {
+			handleOtherPromotions(customer, product, quantity, promotion);
+		}
+	}
+
+	private static void handleCarbonatePromotion(Customer customer, Product product, int quantity,
+		Promotion promotion) {
+		int applicableQuantity = calculateApplicableQuantity(promotion, quantity);
+		int nonApplicableQuantity = calculateNonApplicableQuantity(promotion, quantity);
+
+		displayPromotionMessages(product, applicableQuantity, nonApplicableQuantity);
+
+		if (InputView.checkProceedPurchase().equalsIgnoreCase(ANSWER_YES)) {
+			addGiftAndAdditionalProducts(customer, product, applicableQuantity, nonApplicableQuantity);
+		}
+	}
+
+	private static void handleOtherPromotions(Customer customer, Product product, int quantity, Promotion promotion) {
+		int additionalQuantity = (quantity / promotion.getBuy()) * promotion.getGet();
+
+		if (additionalQuantity > 0) {
+			OutputView.promptPromotionApplicableMessage(product.getName(), additionalQuantity);
+			if (InputView.checkProceedPurchase().equalsIgnoreCase(ANSWER_YES)) {
+				customer.addAdditionalProduct(product.getName(), additionalQuantity);
+				customer.addGiftProduct(product.getName(), additionalQuantity);
+			}
+		}
+	}
+
+	private static int calculateApplicableQuantity(Promotion promotion, int quantity) {
+		return (quantity / promotion.getBuy()) * promotion.getGet();
+	}
+
+	private static int calculateNonApplicableQuantity(Promotion promotion, int quantity) {
+		return quantity % promotion.getBuy();
+	}
+
+	private static void displayPromotionMessages(Product product, int applicableQuantity, int nonApplicableQuantity) {
+		if (nonApplicableQuantity > 0 && applicableQuantity == 0) {
+			OutputView.promptPromotionExceedsMessage(product.getName(), nonApplicableQuantity);
+		}
+		if (applicableQuantity > 0) {
+			OutputView.promptPromotionApplicableMessage(product.getName(), applicableQuantity);
+		}
+	}
+
+	private static void addGiftAndAdditionalProducts(Customer customer, Product product, int applicableQuantity,
+		int nonApplicableQuantity) {
+		if (applicableQuantity > 0) {
+			customer.addGiftProduct(product.getName(), applicableQuantity);
+		}
+		if (nonApplicableQuantity > 0) {
+			customer.addAdditionalProduct(product.getName(), nonApplicableQuantity);
+		}
+	}
+}

리뷰: 위에서 promotion.isApplyPromotion이렇게 하셨던 것처럼 Promotion내부에서 quantity를 받아서 계산한 값을 돌려주는 식으로 했으면 객체 데이터 캡슐화와 책임분리가 됐을 것 같아요!