fix: 댓글 알림에 parentCommentId 필드 추가

src/main/java/com/feesh/domain/notification/dto/NotificationResponseDto.java

@@ -1,5 +1,6 @@
 package com.feesh.domain.notification.dto;
 
+import com.feesh.domain.comment.entity.Comment;
 import com.feesh.domain.notification.entity.Notification;
 import com.feesh.domain.user.entity.User;
 import lombok.Builder;
@@ -16,16 +17,18 @@ public class NotificationResponseDto {
     private String senderNickname;
     private Long postId;
     private Long commentId;
+    private Long parentCommentId;
     private boolean read;
     private LocalDateTime createdAt;
 
-    public static NotificationResponseDto from(Notification notification, User sender) {
+    public static NotificationResponseDto from(Notification notification, User sender, Comment comment) {
         return NotificationResponseDto.builder()
                 .id(notification.getId())
                 .senderId(notification.getSenderId())
                 .senderNickname(sender != null ? sender.getNickname() : null)
                 .postId(notification.getPostId())
                 .commentId(notification.getCommentId())
+                .parentCommentId(comment != null && comment.getParent() != null ? comment.getParent().getId() : null)
                 .read(notification.isRead())
                 .createdAt(notification.getCreatedAt())
                 .build();

src/main/java/com/feesh/domain/notification/service/NotificationService.java

@@ -1,5 +1,7 @@
 package com.feesh.domain.notification.service;
 
+import com.feesh.domain.comment.entity.Comment;
+import com.feesh.domain.comment.repository.CommentRepository;
 import com.feesh.domain.notification.dto.NotificationResponseDto;
 import com.feesh.domain.notification.entity.Notification;
 import com.feesh.domain.notification.entity.NotificationType;
@@ -12,6 +14,7 @@
 
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
@@ -22,6 +25,7 @@ public class NotificationService {
 
     private final NotificationRepository notificationRepository;
     private final UserRepository userRepository;
+    private final CommentRepository commentRepository;
 
     public List<NotificationResponseDto> getCommentAlarms(Long userId) {
         List<Notification> notifications = notificationRepository
@@ -37,7 +41,7 @@ public List<NotificationResponseDto> getLikeAlarms(Long userId) {
         return toResponseDtos(notifications);
     }
 
-    // 알림 목록의 senderId를 모아 유저 정보를 한 번에 조회한 뒤 DTO로 변환 (N+1 방지)
+    // 알림 목록의 senderId, commentId를 모아 각각 한 번에 조회한 뒤 DTO로 변환 (N+1 방지)
     private List<NotificationResponseDto> toResponseDtos(List<Notification> notifications) {
         List<Long> senderIds = notifications.stream()
                 .map(Notification::getSenderId)
@@ -47,10 +51,20 @@ private List<NotificationResponseDto> toResponseDtos(List<Notification> notifica
         Map<Long, User> senderMap = userRepository.findAllById(senderIds).stream()
                 .collect(Collectors.toMap(User::getId, Function.identity()));
 
+        List<Long> commentIds = notifications.stream()
+                .map(Notification::getCommentId)
+                .filter(Objects::nonNull)
+                .distinct()
+                .toList();
+
+        Map<Long, Comment> commentMap = commentRepository.findAllById(commentIds).stream()
+                .collect(Collectors.toMap(Comment::getId, Function.identity()));
+
         return notifications.stream()
                 .map(notification -> NotificationResponseDto.from(
                         notification,
-                        senderMap.get(notification.getSenderId())
+                        senderMap.get(notification.getSenderId()),
+                        commentMap.get(notification.getCommentId())
                 ))
                 .toList();
     }