Merge pull request #60 from Gachigage/feature/product

[Feat] 거래시 제품 수량 감소

Author: dPwls0125

src/main/java/com/gachigage/global/error/ErrorCode.java

@@ -21,7 +21,10 @@ public enum ErrorCode {
 	INTERNAL_SERVER_ERROR(HttpStatus.INTERNAL_SERVER_ERROR, "C006", "서버 내부 오류가 발생했습니다."),
 
 	// 이미지 업로드 오류
-	IMAGE_UPLOAD_FAILED(HttpStatus.INTERNAL_SERVER_ERROR, "I001", "이미지 업로드에 실패했습니다.");
+	IMAGE_UPLOAD_FAILED(HttpStatus.INTERNAL_SERVER_ERROR, "I001", "이미지 업로드에 실패했습니다."),
+
+	// 제품 관룐 에러
+	INSUFFICIENT_STOCK(HttpStatus.BAD_REQUEST, "P001", "재고가 부족합니다.");
 
 	private final HttpStatus httpStatus;
 	private final String code;

src/main/java/com/gachigage/product/domain/Product.java

@@ -281,4 +281,11 @@ private void addImage(ProductImage image) {
 		this.images.add(image);
 		image.setProduct(this);
 	}
+
+	public void deduceStock(Long quantity) {
+		if (this.stock < quantity) {
+			throw new CustomException(ErrorCode.INSUFFICIENT_STOCK, "재고가 부족합니다.");
+		}
+		this.stock -= quantity;
+	}
 }

src/main/java/com/gachigage/trade/service/TradeService.java

@@ -3,6 +3,7 @@
 import java.util.List;
 
 import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
 
 import com.gachigage.chat.domain.ChatRoom;
 import com.gachigage.chat.repository.ChatRoomRepository;
@@ -26,6 +27,7 @@ public class TradeService {
 	private final ChatRoomRepository chatRoomRepository;
 	private final ProductPriceRepository productPriceRepository;
 
+	@Transactional
 	public Trade createTrade(Long chatRoomId, Long productPriceId) {
 		ChatRoom chatRoom = chatRoomRepository.findById(chatRoomId)
 			.orElseThrow(() -> new CustomException(ErrorCode.INVALID_INPUT_VALUE, "존재하지 않는 채팅방입니다."));
@@ -35,6 +37,8 @@ public Trade createTrade(Long chatRoomId, Long productPriceId) {
 			.findById(productPriceId)
 			.orElseThrow(() -> new CustomException(ErrorCode.INVALID_INPUT_VALUE, "존재하지 않는 상품 가격 정보입니다."));
 
+		tradeProduct.deduceStock((long)productPrice.getQuantity());
+
 		Trade trade = Trade.builder()
 			.seller(chatRoom.getSeller())
 			.buyer(chatRoom.getBuyer())