feat(coll): 대댓글 기능 구현

src/main/java/org/devkor/apu/saerok_server/domain/admin/report/application/AdminReportCommandService.java

@@ -153,10 +153,15 @@ public void deleteCommentByReport(Long adminUserId, Long reportId, String reason
         // 1) 관련 신고 정리
         commentReportRepository.deleteByCommentId(commentId);
 
-        // 2) 댓글 삭제
+        // 2) 댓글 삭제 (대댓글이 있으면 soft delete, 없으면 hard delete)
         UserBirdCollectionComment comment = commentRepository.findById(commentId)
                 .orElseThrow(() -> new NotFoundException("해당 댓글이 존재하지 않아요"));
-        commentRepository.remove(comment);
+
+        if (commentRepository.hasReplies(commentId)) {
+            comment.ban();
+        } else {
+            commentRepository.remove(comment);
+        }
 
         // 3) 감사 기록
         User admin = userRepository.findById(adminUserId)

src/main/java/org/devkor/apu/saerok_server/domain/collection/api/dto/request/CreateCollectionCommentRequest.java

@@ -4,6 +4,9 @@
 
 public record CreateCollectionCommentRequest(
         @Schema(description = "댓글 내용", example = "멋진 사진이네요!", requiredMode = Schema.RequiredMode.REQUIRED)
-        String content
+        String content,
+
+        @Schema(description = "부모 댓글 ID (대댓글 작성 시)", example = "123", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+        Long commentId
 ) {
 }

src/main/java/org/devkor/apu/saerok_server/domain/collection/api/dto/response/GetCollectionCommentsResponse.java

@@ -24,6 +24,10 @@ public record Item(
             String thumbnailProfileImageUrl,
             @Schema(description = "댓글 내용", example = "멋진 관찰 기록이네요!", requiredMode = Schema.RequiredMode.REQUIRED)
             String content,
+            @Schema(description = "댓글 상태 (ACTIVE, DELETED, BANNED)", example = "ACTIVE", requiredMode = Schema.RequiredMode.REQUIRED)
+            String status,
+            @Schema(description = "부모 댓글 ID (대댓글인 경우)", example = "5", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+            Long parentId,
             @Schema(description = "좋아요 수", example = "5", requiredMode = Schema.RequiredMode.REQUIRED)
             int likeCount,
             @Schema(description = "좋아요 눌렀는지 여부", example = "true")
@@ -33,7 +37,9 @@ public record Item(
             @Schema(description = "작성 시각", example = "2025-07-05T03:10:00", requiredMode = Schema.RequiredMode.REQUIRED)
             LocalDateTime createdAt,
             @Schema(description = "수정 시각", example = "2025-07-05T04:21:00", requiredMode = Schema.RequiredMode.REQUIRED)
-            LocalDateTime updatedAt
+            LocalDateTime updatedAt,
+            @Schema(description = "대댓글 목록", requiredMode = Schema.RequiredMode.REQUIRED)
+            List<Item> replies
     ) {
 
     }

src/main/java/org/devkor/apu/saerok_server/domain/collection/application/CollectionCommentCommandService.java

@@ -41,20 +41,69 @@ public CreateCollectionCommentResponse createComment(Long userId,
         UserBirdCollection collection = collectionRepository.findById(collectionId)
                 .orElseThrow(() -> new NotFoundException("해당 id의 컬렉션이 존재하지 않아요"));
 
-        UserBirdCollectionComment comment = UserBirdCollectionComment.of(user, collection, req.content());
+        UserBirdCollectionComment comment;
+        UserBirdCollectionComment parentComment = null;
+
+        if (req.commentId() != null) {
+            parentComment = commentRepository.findById(req.commentId())
+                    .orElseThrow(() -> new NotFoundException("존재하지 않는 댓글 id예요"));
+
+            // 같은 컬렉션에 속하는지 확인
+            if (!parentComment.getCollection().getId().equals(collectionId)) {
+                throw new NotFoundException("해당 컬렉션에 속한 댓글이 아니에요");
+            }
+
+            if (!parentComment.isActive()) {
+                throw new ForbiddenException("삭제된 댓글에는 대댓글을 작성할 수 없어요");
+            }
+
+            // depth 1 제한
+            if (parentComment.isReply()) {
+                throw new ForbiddenException("대댓글에는 답글을 작성할 수 없어요");
+            }
+
+            comment = UserBirdCollectionComment.of(user, collection, req.content(), parentComment);
+        } else {
+            comment = UserBirdCollectionComment.of(user, collection, req.content());
+        }
 
         commentRepository.save(comment);
-
-        // 자신의 컬렉션이 아닌 경우에만 푸시 알림 발송
-        if (!collection.getUser().getId().equals(userId)) {
-            notifyAction
-                    .by(Actor.of(userId, user.getNickname()))
-                    .on(Target.collection(collectionId))
-                    .did(ActionKind.COMMENT)
-                    .comment(req.content())
-                    .to(collection.getUser().getId());
+
+        // 알림 전송
+        if (parentComment != null) {
+            // 대댓글인 경우
+            // 1) 원댓글 작성자에게 REPLY 알림
+            if (!parentComment.getUser().getId().equals(userId)) {
+                notifyAction
+                        .by(Actor.of(userId, user.getNickname()))
+                        .on(Target.comment(parentComment.getId()))
+                        .did(ActionKind.REPLY)
+                        .comment(req.content())
+                        .to(parentComment.getUser().getId());
+            }
+
+            // 2) 컬렉션 소유자에게 COMMENT 알림 (원댓글 작성자와 다른 경우에만)
+            if (!collection.getUser().getId().equals(userId)
+                    && !collection.getUser().getId().equals(parentComment.getUser().getId())) {
+                notifyAction
+                        .by(Actor.of(userId, user.getNickname()))
+                        .on(Target.collection(collectionId))
+                        .did(ActionKind.COMMENT)
+                        .comment(req.content())
+                        .to(collection.getUser().getId());
+            }
+        } else {
+            // 원댓글인 경우
+            if (!collection.getUser().getId().equals(userId)) {
+                notifyAction
+                        .by(Actor.of(userId, user.getNickname()))
+                        .on(Target.collection(collectionId))
+                        .did(ActionKind.COMMENT)
+                        .comment(req.content())
+                        .to(collection.getUser().getId());
+            }
         }
-        
+
         return new CreateCollectionCommentResponse(comment.getId());
     }
 
@@ -100,6 +149,11 @@ public void deleteComment(Long userId, Long collectionId, Long commentId) {
             throw new ForbiddenException("해당 댓글에 대한 삭제 권한이 없어요");
         }
 
-        commentRepository.remove(comment);
+        // 대댓글이 있는 경우 soft delete, 없으면 hard delete
+        if (commentRepository.hasReplies(commentId)) {
+            comment.softDelete();
+        } else {
+            commentRepository.remove(comment);
+        }
     }
 }

src/main/java/org/devkor/apu/saerok_server/domain/collection/application/CollectionCommentQueryService.java

@@ -8,6 +8,7 @@
 import org.devkor.apu.saerok_server.domain.collection.core.repository.CollectionCommentLikeRepository;
 import org.devkor.apu.saerok_server.domain.collection.core.repository.CollectionCommentRepository;
 import org.devkor.apu.saerok_server.domain.collection.core.repository.CollectionRepository;
+import org.devkor.apu.saerok_server.domain.collection.core.service.CommentContentResolver;
 import org.devkor.apu.saerok_server.domain.collection.mapper.CollectionCommentWebMapper;
 import org.devkor.apu.saerok_server.domain.user.core.entity.User;
 import org.devkor.apu.saerok_server.domain.user.core.service.UserProfileImageUrlService;
@@ -29,6 +30,7 @@ public class CollectionCommentQueryService {
     private final CollectionCommentLikeRepository commentLikeRepository;
     private final CollectionCommentWebMapper collectionCommentWebMapper;
     private final UserProfileImageUrlService userProfileImageUrlService;
+    private final CommentContentResolver commentContentResolver;
 
     /* 댓글 목록 (createdAt ASC) */
     public GetCollectionCommentsResponse getComments(Long collectionId, Long userId) {
@@ -72,7 +74,7 @@ public GetCollectionCommentsResponse getComments(Long collectionId, Long userId)
         Map<Long, String> thumbnailProfileImageUrls = userProfileImageUrlService.getProfileThumbnailImageUrlsFor(users);
 
         // 7. 응답 생성
-        return collectionCommentWebMapper.toGetCollectionCommentsResponse(comments, likeCounts, likeStatuses, mineStatuses, profileImageUrls, thumbnailProfileImageUrls, isMyCollection);
+        return collectionCommentWebMapper.toGetCollectionCommentsResponse(comments, likeCounts, likeStatuses, mineStatuses, profileImageUrls, thumbnailProfileImageUrls, isMyCollection, commentContentResolver);
     }
 
     /* 댓글 개수 */

src/main/java/org/devkor/apu/saerok_server/domain/collection/core/entity/CommentStatus.java

@@ -0,0 +1,7 @@
+package org.devkor.apu.saerok_server.domain.collection.core.entity;
+
+public enum CommentStatus {
+    ACTIVE,
+    DELETED,
+    BANNED
+}

src/main/java/org/devkor/apu/saerok_server/domain/collection/core/entity/UserBirdCollectionComment.java

@@ -28,12 +28,45 @@ public class UserBirdCollectionComment extends Auditable {
     @Column(name = "content", nullable = false)
     private String content;
 
+    @Enumerated(EnumType.STRING)
+    @Column(name = "status", nullable = false, length = 32)
+    private CommentStatus status = CommentStatus.ACTIVE;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "parent_id")
+    private UserBirdCollectionComment parent;
+
     public static UserBirdCollectionComment of(User user, UserBirdCollection collection, String content) {
         UserBirdCollectionComment comment = new UserBirdCollectionComment();
         comment.user = user;
         comment.collection = collection;
         comment.content = content;
+        comment.status = CommentStatus.ACTIVE;
+
+        return comment;
+    }
+
+    public static UserBirdCollectionComment of(User user, UserBirdCollection collection, String content, UserBirdCollectionComment parent) {
+        UserBirdCollectionComment comment = of(user, collection, content);
+        comment.parent = parent;
 
         return comment;
     }
+
+    public void softDelete() {
+        this.status = CommentStatus.DELETED;
+    }
+
+    public void ban() {
+        this.status = CommentStatus.BANNED;
+    }
+
+    public boolean isActive() {
+        return this.status == CommentStatus.ACTIVE;
+    }
+
+    public boolean isReply() {
+        return this.parent != null;
+    }
+
 }

src/main/java/org/devkor/apu/saerok_server/domain/collection/core/repository/CollectionCommentRepository.java

@@ -26,7 +26,9 @@ public Optional<UserBirdCollectionComment> findById(Long id) {
 
     public List<UserBirdCollectionComment> findByCollectionId(Long collectionId) {
         return em.createQuery(
-                        "SELECT c FROM UserBirdCollectionComment c " +
+                        "SELECT DISTINCT c FROM UserBirdCollectionComment c " +
+                                "LEFT JOIN FETCH c.user " +
+                                "LEFT JOIN FETCH c.parent " +
                                 "WHERE c.collection.id = :collectionId " +
                                 "ORDER BY c.createdAt ASC",
                         UserBirdCollectionComment.class)
@@ -36,16 +38,27 @@ public List<UserBirdCollectionComment> findByCollectionId(Long collectionId) {
 
     public long countByCollectionId(Long collectionId) {
         return em.createQuery(
-                        "SELECT COUNT(c) FROM UserBirdCollectionComment c WHERE c.collection.id = :collectionId",
+                        "SELECT COUNT(c) FROM UserBirdCollectionComment c " +
+                                "WHERE c.collection.id = :collectionId " +
+                                "AND c.status = org.devkor.apu.saerok_server.domain.collection.core.entity.CommentStatus.ACTIVE",
                         Long.class)
                 .setParameter("collectionId", collectionId)
                 .getSingleResult();
     }
 
+    public boolean hasReplies(Long commentId) {
+        Long count = em.createQuery(
+                        "SELECT COUNT(c) FROM UserBirdCollectionComment c WHERE c.parent.id = :commentId",
+                        Long.class)
+                .setParameter("commentId", commentId)
+                .getSingleResult();
+        return count > 0;
+    }
+
     /* ────────────────────────────── 성능 최적화: 배치 메서드 ────────────────────────────── */
 
     /**
-     * 여러 컬렉션의 댓글 수를 한 번에 조회
+     * 여러 컬렉션의 ACTIVE 댓글 수를 한 번에 조회
      * 반환 맵은 요청한 ID를 모두 포함하며, 없으면 0으로 채운다.
      */
     public Map<Long, Long> countByCollectionIds(List<Long> collectionIds) {
@@ -57,6 +70,7 @@ public Map<Long, Long> countByCollectionIds(List<Long> collectionIds) {
                         "SELECT c.collection.id, COUNT(c) " +
                                 "FROM UserBirdCollectionComment c " +
                                 "WHERE c.collection.id IN :ids " +
+                                "AND c.status = org.devkor.apu.saerok_server.domain.collection.core.entity.CommentStatus.ACTIVE " +
                                 "GROUP BY c.collection.id",
                         Object[].class)
                 .setParameter("ids", collectionIds)

src/main/java/org/devkor/apu/saerok_server/domain/collection/core/service/CommentContentResolver.java

@@ -0,0 +1,23 @@
+package org.devkor.apu.saerok_server.domain.collection.core.service;
+
+import lombok.RequiredArgsConstructor;
+import org.devkor.apu.saerok_server.domain.collection.core.entity.CommentStatus;
+import org.devkor.apu.saerok_server.global.core.config.feature.CommentReplacementConfig;
+import org.springframework.stereotype.Service;
+
+@Service
+@RequiredArgsConstructor
+public class CommentContentResolver {
+
+    private final CommentReplacementConfig commentReplacementConfig;
+
+    /**
+     * 댓글 상태에 따라 적절한 content를 반환합니다.
+     * - ACTIVE: 원본 content 반환
+     * - DELETED, BANNED: 설정 파일에 정의된 대체 메시지 반환
+     */
+    public String resolveContent(String originalContent, CommentStatus status) {
+        String replacement = commentReplacementConfig.getReplacement(status);
+        return replacement != null ? replacement : originalContent;
+    }
+}