예약 취소 기능 구현

src/main/java/com/reservation/tablereservationservice/application/reservation/service/ReservationService.java

@@ -161,27 +161,52 @@ private Page<ReservationListResponseDto> createReservationListDtoPage(
 		return page.map(reservation -> {
 			User user = idToUser.get(reservation.getUserId());
 			if (user == null) {
-				throw new ReservationException(ErrorCode.RESOURCE_NOT_FOUND,
-					"User (userId=" + reservation.getUserId() + ")");
+				throw new ReservationException(
+					ErrorCode.RESOURCE_NOT_FOUND,
+					"User (userId=" + reservation.getUserId() + ")"
+				);
 			}
 
 			RestaurantSlot slot = idToSlot.get(reservation.getSlotId());
 			if (slot == null) {
-				throw new ReservationException(ErrorCode.RESOURCE_NOT_FOUND,
+				throw new ReservationException(
+					ErrorCode.RESOURCE_NOT_FOUND,
 					"RestaurantSlot (slotId=" + reservation.getSlotId() + ")"
 				);
 			}
 
 			Restaurant restaurant = idToRestaurant.get(slot.getRestaurantId());
 			if (restaurant == null) {
-				throw new ReservationException(ErrorCode.RESOURCE_NOT_FOUND,
-					"Restaurant (restaurantId=" + slot.getRestaurantId() + ")");
+				throw new ReservationException(
+					ErrorCode.RESOURCE_NOT_FOUND,
+					"Restaurant (restaurantId=" + slot.getRestaurantId() + ")"
+				);
 			}
 
 			return ReservationListResponseDto.of(user, reservation, restaurant);
 		});
 	}
 
+	@Transactional
+	public Reservation cancel(String email, Long reservationId) {
+		User user = userRepository.fetchByEmail(email);
+
+		Reservation reservation = reservationRepository.fetchById(reservationId);
+
+		LocalDateTime now = LocalDateTime.now();
+		validateCancelable(user.getUserId(), reservation, now);
+		reservation.cancel();
+
+		DailySlotCapacity capacity = dailySlotCapacityRepository
+			.findBySlotIdAndDate(reservation.getSlotId(), reservation.getVisitAt().toLocalDate())
+			.orElseThrow(() -> new ReservationException(ErrorCode.RESERVATION_SLOT_NOT_OPENED));
+
+		restoreCapacity(capacity, reservation.getPartySize());
+		reservationRepository.updateStatus(reservation);
+
+		return reservation;
+	}
+
 	private Map<Long, RestaurantSlot> loadSlotMap(Page<Reservation> page) {
 		List<Long> slotIds = page.getContent().stream()
 			.map(Reservation::getSlotId)
@@ -221,4 +246,23 @@ private void decreaseCapacity(DailySlotCapacity capacity, int partySize) {
 		dailySlotCapacityRepository.updateRemainingCount(capacity);
 	}
 
+	private void validateCancelable(Long userId, Reservation reservation, LocalDateTime now) {
+		if (!reservation.isOwner(userId)) {
+			throw new ReservationException(ErrorCode.RESERVATION_FORBIDDEN);
+		}
+
+		if (reservation.isAlreadyCanceled()) {
+			throw new ReservationException(ErrorCode.RESERVATION_ALREADY_CANCELED);
+		}
+
+		if (!reservation.canCancelAt(now)) {
+			throw new ReservationException(ErrorCode.RESERVATION_CANCEL_DEADLINE_PASSED);
+		}
+	}
+
+	private void restoreCapacity(DailySlotCapacity capacity, int partySize) {
+		capacity.increase(partySize);
+		dailySlotCapacityRepository.updateRemainingCount(capacity);
+	}
+
 }

src/main/java/com/reservation/tablereservationservice/domain/reservation/DailySlotCapacity.java

@@ -35,4 +35,8 @@ public boolean decrease(int partySize) {
 		return true;
 	}
 
+	public void increase(int partySize) {
+		this.remainingCount += partySize;
+	}
+
 }

src/main/java/com/reservation/tablereservationservice/domain/reservation/Reservation.java

@@ -28,4 +28,25 @@ public Reservation(Long reservationId, Long userId, Long slotId, LocalDateTime v
 		this.status = status;
 	}
 
+	public boolean isOwner(Long userId) {
+		return this.userId != null && this.userId.equals(userId);
+	}
+
+	public boolean isAlreadyCanceled() {
+		return this.status == ReservationStatus.CANCELED;
+	}
+
+	/**
+	 * 취소 가능 기한(방문 24시간 전) 내에 있는지 확인
+	 * @param now 현재 시점
+	 */
+	public boolean canCancelAt(LocalDateTime now) {
+		LocalDateTime cancelDeadline = this.visitAt.minusHours(24);
+		return now.isBefore(cancelDeadline);
+	}
+
+	public void cancel() {
+		this.status = ReservationStatus.CANCELED;
+	}
+
 }

src/main/java/com/reservation/tablereservationservice/domain/reservation/ReservationRepository.java

@@ -5,6 +5,7 @@
 
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
+import java.util.Optional;
 
 public interface ReservationRepository {
 
@@ -28,5 +29,11 @@ Page<Reservation> findOwnerReservations(
 		Pageable pageable
 	);
 
+	Optional<Reservation> findById(Long reservationId);
+
+	Reservation fetchById(Long reservationId);
+
+	void updateStatus(Reservation reservation);
+
 	void deleteAll();
 }

src/main/java/com/reservation/tablereservationservice/global/exception/ErrorCode.java

@@ -15,6 +15,8 @@ public enum ErrorCode {
 	INVALID_PARTY_SIZE("예약 인원 수가 올바르지 않습니다.", HttpStatus.BAD_REQUEST),
 	RESERVATION_SLOT_NOT_OPENED("해당 날짜의 예약이 오픈되지 않았습니다.", HttpStatus.BAD_REQUEST),
 	INVALID_RESERVATION_REQUEST("유효하지 않은 예약 요청입니다.", HttpStatus.BAD_REQUEST),
+	RESERVATION_ALREADY_CANCELED("이미 취소된 예약입니다.", HttpStatus.BAD_REQUEST),
+	RESERVATION_CANCEL_DEADLINE_PASSED("예약 취소는 방문 24시간 전까지 가능합니다.", HttpStatus.BAD_REQUEST),
 
 	// 401 Unauthorized
 	UNAUTHORIZED("인증되지 않은 사용자입니다.", HttpStatus.UNAUTHORIZED),
@@ -24,6 +26,7 @@ public enum ErrorCode {
 
 	// 403 Forbidden
 	ACCESS_DENIED("접근 권한이 없습니다.", HttpStatus.FORBIDDEN),
+	RESERVATION_FORBIDDEN("본인의 예약만 취소할 수 있습니다.", HttpStatus.FORBIDDEN),
 
 	// 404 Not Found
 	RESOURCE_NOT_FOUND("%s를(을) 찾을 수 없습니다.", HttpStatus.NOT_FOUND),
@@ -41,4 +44,4 @@ public enum ErrorCode {
 
 	private final String message;
 	private final HttpStatus status;
-}
+	}

src/main/java/com/reservation/tablereservationservice/infrastructure/reservation/entity/ReservationEntity.java

@@ -65,4 +65,8 @@ public ReservationEntity(Long userId, Long slotId, LocalDateTime visitAt, Intege
 		this.note = note;
 		this.status = status;
 	}
+
+	public void updateStatus(ReservationStatus status) {
+	    this.status = status;
+	}
 }

src/main/java/com/reservation/tablereservationservice/infrastructure/reservation/repository/JpaReservationRepository.java

@@ -2,6 +2,7 @@
 
 import java.time.LocalDateTime;
 import java.util.List;
+import java.util.Optional;
 
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
@@ -10,6 +11,8 @@
 import com.reservation.tablereservationservice.domain.reservation.Reservation;
 import com.reservation.tablereservationservice.domain.reservation.ReservationRepository;
 import com.reservation.tablereservationservice.domain.reservation.ReservationStatus;
+import com.reservation.tablereservationservice.global.exception.ErrorCode;
+import com.reservation.tablereservationservice.global.exception.ReservationException;
 import com.reservation.tablereservationservice.infrastructure.reservation.entity.ReservationEntity;
 import com.reservation.tablereservationservice.infrastructure.reservation.mapper.ReservationMapper;
 
@@ -65,6 +68,27 @@ public Page<Reservation> findOwnerReservations(
 			.map(ReservationMapper.INSTANCE::toDomain);
 	}
 
+	@Override
+	public Optional<Reservation> findById(Long reservationId) {
+		return reservationEntityRepository.findById(reservationId)
+			.map(ReservationMapper.INSTANCE::toDomain);
+	}
+
+	@Override
+	public Reservation fetchById(Long reservationId) {
+		return findById(reservationId)
+			.orElseThrow(() -> new ReservationException(ErrorCode.RESOURCE_NOT_FOUND, "Reservation"));
+	}
+
+	@Override
+	public void updateStatus(Reservation reservation) {
+		ReservationEntity entity = reservationEntityRepository.findById(reservation.getReservationId())
+			.orElseThrow(() -> new ReservationException(ErrorCode.RESOURCE_NOT_FOUND, "Reservation"));
+
+		entity.updateStatus(reservation.getStatus());
+		// save() 호출 없음 -> 변경 감지 UPDATE
+	}
+
 	@Override
 	public void deleteAll() {
 		reservationEntityRepository.deleteAll();

src/main/java/com/reservation/tablereservationservice/presentation/reservation/controller/ReservationController.java

@@ -3,9 +3,9 @@
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Sort;
 import org.springframework.data.web.PageableDefault;
-import org.springframework.security.access.prepost.PreAuthorize;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.ModelAttribute;
+import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMapping;
@@ -81,4 +81,13 @@ public ApiResponse<PageResponseDto<ReservationListResponseDto>> findOwnerReserva
 
 	}
 
+	@CustomerOnly
+	@PostMapping("/{reservationId}/cancel")
+	public ApiResponse<ReservationResponseDto> cancel(@PathVariable Long reservationId, @LoginUser CurrentUser user) {
+		Reservation reservation = reservationService.cancel(user.email(), reservationId);
+		ReservationResponseDto responseDto = ReservationResponseDto.from(reservation);
+
+		return ApiResponse.success("예약 취소 성공", responseDto);
+	}
+
 }