[Feat] 댓글 수정 및 삭제 API 구현

backend/src/main/java/com/example/Piroin/project/domain/question/controller/QuestionController.java

@@ -119,6 +119,29 @@ public ResponseEntity<ApiResponse<QuestionResDTO.StatusUpdateRes>> updateQuestio
                 questionService.updateQuestionStatus(questionId, userId));
     }
 
+    // 댓글 수정
+    // PATCH /api/comments/{commentId}
+    @PatchMapping("/api/comments/{commentId}")
+    public ResponseEntity<ApiResponse<QuestionResDTO.CommentUpdateDeleteRes>> updateComment(
+            @PathVariable Long commentId,
+            @RequestBody QuestionReqDTO.CommentUpdateReq request,
+            @AuthenticationPrincipal Long userId
+    ) {
+        return ResponseUtil.success(QuestionSuccessCode.COMMENT_UPDATED,
+                questionService.updateComment(commentId, request, userId));
+    }
+
+    // 댓글 삭제
+    // DELETE /api/comments/{commentId}
+    @DeleteMapping("/api/comments/{commentId}")
+    public ResponseEntity<ApiResponse<QuestionResDTO.CommentUpdateDeleteRes>> deleteComment(
+            @PathVariable Long commentId,
+            @AuthenticationPrincipal Long userId
+    ) {
+        return ResponseUtil.success(QuestionSuccessCode.COMMENT_DELETED,
+                questionService.deleteComment(commentId, userId));
+    }
+
     // 이해도 체크 생성
     // POST /api/sessions/{sessionId}/understanding-checks
     @PostMapping("/api/sessions/{sessionId}/understanding-checks")

backend/src/main/java/com/example/Piroin/project/domain/question/dto/QuestionReqDTO.java

@@ -31,6 +31,13 @@ public static class CommentReq {
         private Long parentCommentId;  // 대댓글일 때만 값이 있음, 일반 댓글이면 null
     }
 
+    // 댓글 수정 요청
+    @Getter
+    @NoArgsConstructor
+    public static class CommentUpdateReq {
+        private String content;
+    }
+
     // 이해도 체크 응답 요청
     @Getter
     @NoArgsConstructor

backend/src/main/java/com/example/Piroin/project/domain/question/dto/QuestionResDTO.java

@@ -41,6 +41,15 @@ public record CommentCreateRes(
     ) {
     }
 
+    // 댓글 수정/삭제 응답
+    public record CommentUpdateDeleteRes(
+            Long commentId,
+            String content,
+            LocalDateTime updatedAt,
+            LocalDateTime deletedAt
+    ) {
+    }
+
     // 좋아요 토글 응답
     // isLiked: true면 좋아요 추가된 상태, false면 취소된 상태
     public record LikeRes(

backend/src/main/java/com/example/Piroin/project/domain/question/entity/QuestionComment.java

@@ -50,4 +50,16 @@ public class QuestionComment {
 
     @Column(name = "deleted_at")
     private LocalDateTime deletedAt;
+
+    // 댓글 내용 수정
+    public void updateContent(String content) {
+        this.content = content;
+        this.updatedAt = LocalDateTime.now();
+    }
+
+    // 댓글 소프트 삭제
+    public void softDelete() {
+        this.deletedAt = LocalDateTime.now();
+        this.updatedAt = LocalDateTime.now();
+    }
 }

backend/src/main/java/com/example/Piroin/project/domain/question/exception/code/QuestionSuccessCode.java

@@ -18,6 +18,8 @@ public enum QuestionSuccessCode implements BaseCode {
     QUESTION_STATUS_UPDATED(HttpStatus.OK, "QUESTION200_7", "질문 상태가 변경되었습니다."),
     QUESTION_CREATED(HttpStatus.CREATED, "QUESTION201_1", "질문이 등록되었습니다."),
     COMMENT_CREATED(HttpStatus.CREATED, "QUESTION201_2", "댓글이 등록되었습니다."),
+    COMMENT_UPDATED(HttpStatus.OK, "QUESTION200_8", "댓글이 수정되었습니다."),
+    COMMENT_DELETED(HttpStatus.OK, "QUESTION200_9", "댓글이 삭제되었습니다."),
     UNDERSTANDING_CHECK_CREATED(HttpStatus.CREATED, "QUESTION201_3", "이해도 체크가 생성되었습니다.");
 
     private final HttpStatus status;

backend/src/main/java/com/example/Piroin/project/domain/question/service/QuestionService.java

@@ -298,6 +298,40 @@ public QuestionResDTO.UpdateDeleteRes deleteQuestion(Long questionId, Long userI
         );
     }
 
+    // 댓글 수정
+    @Transactional
+    public QuestionResDTO.CommentUpdateDeleteRes updateComment(
+            Long commentId,
+            QuestionReqDTO.CommentUpdateReq request,
+            Long userId
+    ) {
+        User loginUser = findLoginUser(userId);
+        QuestionComment comment = findComment(commentId);
+        validateCommentOwner(comment, loginUser);
+
+        comment.updateContent(request.getContent());
+
+        return new QuestionResDTO.CommentUpdateDeleteRes(
+                comment.getId(), comment.getContent(),
+                comment.getUpdatedAt(), comment.getDeletedAt()
+        );
+    }
+
+    // 댓글 삭제
+    @Transactional
+    public QuestionResDTO.CommentUpdateDeleteRes deleteComment(Long commentId, Long userId) {
+        User loginUser = findLoginUser(userId);
+        QuestionComment comment = findComment(commentId);
+        validateCommentOwner(comment, loginUser);
+
+        comment.softDelete();
+
+        return new QuestionResDTO.CommentUpdateDeleteRes(
+                comment.getId(), comment.getContent(),
+                comment.getUpdatedAt(), comment.getDeletedAt()
+        );
+    }
+
     // 질문 상태 완료 전환
     // PATCH /api/questions/{questionId}/status
     @Transactional
@@ -404,6 +438,18 @@ private void validateQuestionOwner(Question question, User loginUser) {
         }
     }
 
+    private void validateCommentOwner(QuestionComment comment, User loginUser) {
+        if (!comment.getUser().getId().equals(loginUser.getId())) {
+            throw new QuestionException(HttpStatus.FORBIDDEN, "본인의 댓글만 수정/삭제할 수 있습니다.");
+        }
+    }
+
+    private QuestionComment findComment(Long commentId) {
+        return questionCommentRepository.findById(commentId)
+                .filter(c -> c.getDeletedAt() == null)
+                .orElseThrow(() -> new QuestionException(HttpStatus.NOT_FOUND, "댓글을 찾을 수 없습니다."));
+    }
+
     private UnderstandResChoice applyUnderstandingResponse(
             UnderstandingCheck check, User loginUser, UnderstandResChoice requestedChoice
     ) {