feat(community): 댓글-대댓글 구조로 댓글 조회 service 및 usecase 추가

Author: ayoung-dev

src/main/java/com/somemore/community/service/comment/CommunityCommentQueryService.java

@@ -0,0 +1,78 @@
+package com.somemore.community.service.comment;
+
+import com.somemore.community.domain.CommunityComment;
+import com.somemore.community.dto.response.CommunityCommentResponseDto;
+import com.somemore.community.repository.comment.CommunityCommentRepository;
+import com.somemore.community.repository.mapper.CommunityCommentView;
+import com.somemore.community.usecase.comment.CommunityCommentQueryUseCase;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.util.*;
+
+@RequiredArgsConstructor
+@Transactional(readOnly = true)
+@Service
+public class CommunityCommentQueryService implements CommunityCommentQueryUseCase {
+
+    private final CommunityCommentRepository communityCommentRepository;
+
+    @Override
+    public List<CommunityCommentResponseDto> getCommunityCommentsByBoardId(Long boardId) {
+        List<CommunityCommentView> allComments = communityCommentRepository.findCommentsByBoardId(boardId);
+        List<CommunityCommentView> filteredComments = filterValidComments(allComments);
+        return createCommentHierarchy(filteredComments);
+    }
+
+    private List<CommunityCommentView> filterValidComments(List<CommunityCommentView> comments) {
+        List<Long> parentCommentIds = findParentCommentIds(comments);
+
+        return comments.stream()
+                .flatMap(comment -> processDeletedComment(parentCommentIds, comment).stream())
+                .toList();
+    }
+
+    private List<Long> findParentCommentIds(List<CommunityCommentView> comments) {
+        return comments.stream()
+                .filter(comment -> !comment.communityComment().getDeleted())
+                .map(comment -> comment.communityComment().getParentCommentId())
+                .filter(Objects::nonNull)
+                .toList();
+    }
+
+    private Optional<CommunityCommentView> processDeletedComment(List<Long> parentCommentIds, CommunityCommentView commentView) {
+        CommunityComment comment = commentView.communityComment();
+
+        if (comment.getDeleted()) {
+            if (parentCommentIds.contains(comment.getId())) {
+                return Optional.of(commentView.replaceWriterNickname(commentView));
+            }
+            return Optional.empty();
+        }
+
+        return Optional.of(commentView);
+    }
+
+    private List<CommunityCommentResponseDto> createCommentHierarchy(List<CommunityCommentView> comments) {
+
+        Map<Long, CommunityCommentResponseDto> commentMap = new HashMap<>();
+        List<CommunityCommentResponseDto> rootComments = new ArrayList<>();
+
+        for (CommunityCommentView comment : comments) {
+            CommunityCommentResponseDto dto = CommunityCommentResponseDto.fromView(comment);
+            commentMap.put(dto.id(), dto);
+
+            Long parentCommentId = comment.communityComment().getParentCommentId();
+
+            if (parentCommentId == null) {
+                rootComments.add(dto);
+            } else {
+                commentMap.get(parentCommentId).addReply(dto);
+            }
+        }
+
+        return rootComments;
+    }
+}
+

src/main/java/com/somemore/community/usecase/comment/CommunityCommentQueryUseCase.java

@@ -0,0 +1,9 @@
+package com.somemore.community.usecase.comment;
+
+import com.somemore.community.dto.response.CommunityCommentResponseDto;
+
+import java.util.List;
+
+public interface CommunityCommentQueryUseCase {
+    List<CommunityCommentResponseDto> getCommunityCommentsByBoardId(Long boardId);
+}