refactor: 결제 테이블 coupon_id 컬럼을 discount_amount로 변경

src/main/java/com/moabam/api/application/payment/PaymentMapper.java

@@ -19,7 +19,7 @@ public static Payment toPayment(Long memberId, Product product) {
 			.memberId(memberId)
 			.product(product)
 			.order(order)
-			.amount(product.getPrice())
+			.totalAmount(product.getPrice())
 			.build();
 	}
 }

src/main/java/com/moabam/api/application/product/ProductMapper.java

@@ -35,7 +35,7 @@ public static PurchaseProductResponse toPurchaseProductResponse(Payment payment)
 		return PurchaseProductResponse.builder()
 			.paymentId(payment.getId())
 			.orderName(payment.getOrder().getName())
-			.price(payment.getAmount())
+			.price(payment.getTotalAmount())
 			.build();
 	}
 }

src/main/java/com/moabam/api/domain/payment/Payment.java

@@ -52,18 +52,17 @@ public class Payment {
 	@JoinColumn(name = "product_id", updatable = false, nullable = false)
 	private Product product;
 
-	@ManyToOne(fetch = FetchType.LAZY)
-	@JoinColumn(name = "coupon_id")
-	private Coupon coupon;
-
 	@Column(name = "coupon_wallet_id")
 	private Long couponWalletId;
 
 	@Embedded
 	private Order order;
 
-	@Column(name = "amount", nullable = false)
-	private int amount;
+	@Column(name = "total_amount", nullable = false)
+	private int totalAmount;
+
+	@Column(name = "discount_amount", nullable = false)
+	private int discountAmount;
 
 	@Column(name = "payment_key")
 	private String paymentKey;
@@ -83,14 +82,14 @@ public class Payment {
 	private LocalDateTime approvedAt;
 
 	@Builder
-	public Payment(Long memberId, Product product, Coupon coupon, Long couponWalletId, Order order, int amount,
-		PaymentStatus status) {
+	public Payment(Long memberId, Product product, Long couponWalletId, Order order, int totalAmount,
+		int discountAmount, PaymentStatus status) {
 		this.memberId = requireNonNull(memberId);
 		this.product = requireNonNull(product);
-		this.coupon = coupon;
 		this.couponWalletId = couponWalletId;
 		this.order = requireNonNull(order);
-		this.amount = validateAmount(amount);
+		this.totalAmount = validateAmount(totalAmount);
+		this.discountAmount = validateAmount(discountAmount);
 		this.status = requireNonNullElse(status, PaymentStatus.READY);
 	}
 
@@ -104,7 +103,7 @@ private int validateAmount(int amount) {
 
 	public void validateInfo(Long memberId, int amount) {
 		validateByMember(memberId);
-		validateByAmount(amount);
+		validateByTotalAmount(amount);
 	}
 
 	public void validateByMember(Long memberId) {
@@ -113,8 +112,8 @@ public void validateByMember(Long memberId) {
 		}
 	}
 
-	private void validateByAmount(int amount) {
-		if (this.amount != amount) {
+	private void validateByTotalAmount(int amount) {
+		if (this.totalAmount != amount) {
 			throw new BadRequestException(INVALID_PAYMENT_INFO);
 		}
 	}
@@ -124,9 +123,9 @@ public boolean isCouponApplied() {
 	}
 
 	public void applyCoupon(Coupon coupon, Long couponWalletId) {
-		this.coupon = coupon;
 		this.couponWalletId = couponWalletId;
-		this.amount = Math.max(MIN_AMOUNT, this.amount - coupon.getPoint());
+		this.discountAmount = coupon.getPoint();
+		this.totalAmount = Math.max(MIN_AMOUNT, this.totalAmount - coupon.getPoint());
 	}
 
 	public void request(String orderId) {

src/test/java/com/moabam/api/domain/payment/PaymentTest.java

@@ -21,7 +21,7 @@ void validate_amount_exception() {
 			.memberId(1L)
 			.product(bugProduct())
 			.order(order(bugProduct()))
-			.amount(-1000);
+			.totalAmount(-1000);
 
 		assertThatThrownBy(paymentBuilder::build)
 			.isInstanceOf(BadRequestException.class)
@@ -44,8 +44,8 @@ void success() {
 			payment.applyCoupon(coupon, couponWalletId);
 
 			// then
-			assertThat(payment.getAmount()).isEqualTo(BUG_PRODUCT_PRICE - 1000);
-			assertThat(payment.getCoupon()).isEqualTo(coupon);
+			assertThat(payment.getTotalAmount()).isEqualTo(BUG_PRODUCT_PRICE - 1000);
+			assertThat(payment.getDiscountAmount()).isEqualTo(coupon.getPoint());
 			assertThat(payment.getCouponWalletId()).isEqualTo(couponWalletId);
 		}
 
@@ -61,7 +61,7 @@ void discount_amount_greater() {
 			payment.applyCoupon(coupon, couponWalletId);
 
 			// then
-			assertThat(payment.getAmount()).isZero();
+			assertThat(payment.getTotalAmount()).isZero();
 		}
 	}
 

src/test/java/com/moabam/support/fixture/PaymentFixture.java

@@ -24,18 +24,18 @@ public static Payment payment(Product product) {
 			.memberId(1L)
 			.product(product)
 			.order(order(product))
-			.amount(product.getPrice())
+			.totalAmount(product.getPrice())
 			.build();
 	}
 
 	public static Payment paymentWithCoupon(Product product, Coupon coupon, Long couponWalletId) {
 		return Payment.builder()
 			.memberId(1L)
 			.product(product)
-			.coupon(coupon)
 			.couponWalletId(couponWalletId)
 			.order(order(product))
-			.amount(product.getPrice())
+			.totalAmount(product.getPrice())
+			.discountAmount(coupon.getPoint())
 			.build();
 	}