모임 댓글 기능 구현

backend/src/main/java/mouda/backend/comment/domain/Comment.java

@@ -1,34 +1,87 @@
 package mouda.backend.comment.domain;
 
+import java.time.LocalDateTime;
+
+import org.springframework.http.HttpStatus;
+
+import jakarta.persistence.Column;
 import jakarta.persistence.Entity;
 import jakarta.persistence.GeneratedValue;
 import jakarta.persistence.GenerationType;
 import jakarta.persistence.Id;
-import jakarta.persistence.JoinColumn;
 import jakarta.persistence.ManyToOne;
+import lombok.Builder;
 import lombok.Getter;
 import lombok.NoArgsConstructor;
+import mouda.backend.comment.exception.CommentErrorMessage;
+import mouda.backend.comment.exception.CommentException;
 import mouda.backend.member.domain.Member;
 import mouda.backend.moim.domain.Moim;
+import mouda.backend.moim.exception.MoimErrorMessage;
+import mouda.backend.moim.exception.MoimException;
 
 @Entity
 @Getter
 @NoArgsConstructor
 public class Comment {
-	
+
 	@Id
 	@GeneratedValue(strategy = GenerationType.IDENTITY)
 	private Long id;
 
+	@Column(nullable = false)
 	private String content;
 
 	@ManyToOne
-	@JoinColumn(name = "moim_id")
 	private Moim moim;
 
 	@ManyToOne
-	@JoinColumn(name = "member_id")
 	private Member member;
 
+	@Column(nullable = false)
+	private LocalDateTime createdAt;
+
 	private Long parentId;
+
+	@Builder
+	public Comment(String content, Moim moim, Member member, LocalDateTime createdAt, Long parentId) {
+		validateContent(content);
+		validateMoim(moim);
+		validateMember(member);
+		this.content = content;
+		this.moim = moim;
+		this.member = member;
+		this.createdAt = createdAt;
+		this.parentId = parentId;
+	}
+
+	private void validateContent(String content) {
+		if (content == null || content.isBlank()) {
+			throw new CommentException(HttpStatus.BAD_REQUEST, CommentErrorMessage.CONTENT_NOT_FOUND);
+		}
+	}
+
+	private void validateMoim(Moim moim) {
+		if (moim == null) {
+			throw new MoimException(HttpStatus.NOT_FOUND, MoimErrorMessage.NOT_FOUND);
+		}
+	}
+
+	private void validateMember(Member member) {
+		if (member == null) {
+			throw new CommentException(HttpStatus.NOT_FOUND, CommentErrorMessage.MEMBER_NOT_FOUND);
+		}
+	}
+
+	public boolean isParent() {
+		return parentId == null;
+	}
+
+	public boolean isChild() {
+		return parentId != null;
+	}
+
+	public String getAuthorNickname() {
+		return member.getNickname();
+	}
 }

backend/src/main/java/mouda/backend/comment/dto/request/CommentCreateRequest.java

@@ -0,0 +1,25 @@
+package mouda.backend.comment.dto.request;
+
+import java.time.LocalDateTime;
+
+import jakarta.validation.constraints.NotNull;
+import mouda.backend.comment.domain.Comment;
+import mouda.backend.member.domain.Member;
+import mouda.backend.moim.domain.Moim;
+
+public record CommentCreateRequest(
+	Long parentId,
+
+	@NotNull
+	String content
+) {
+	public Comment toEntity(Moim moim, Member member) {
+		return Comment.builder()
+			.content(content)
+			.moim(moim)
+			.member(member)
+			.createdAt(LocalDateTime.now())
+			.parentId(parentId)
+			.build();
+	}
+}

backend/src/main/java/mouda/backend/comment/dto/response/ChildCommentResponse.java

@@ -0,0 +1,29 @@
+package mouda.backend.comment.dto.response;
+
+import java.time.LocalDateTime;
+
+import com.fasterxml.jackson.annotation.JsonFormat;
+
+import lombok.Builder;
+import mouda.backend.comment.domain.Comment;
+
+@Builder
+public record ChildCommentResponse(
+	Long commentId,
+
+	String nickname,
+
+	String content,
+
+	@JsonFormat(pattern = "yyyy-MM-dd HH:mm")
+	LocalDateTime dateTime
+) {
+	public static ChildCommentResponse toResponse(Comment comment) {
+		return ChildCommentResponse.builder()
+			.commentId(comment.getId())
+			.nickname(comment.getAuthorNickname())
+			.content(comment.getContent())
+			.dateTime(comment.getCreatedAt())
+			.build();
+	}
+}

backend/src/main/java/mouda/backend/comment/dto/response/CommentResponse.java

@@ -0,0 +1,33 @@
+package mouda.backend.comment.dto.response;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+import com.fasterxml.jackson.annotation.JsonFormat;
+
+import lombok.Builder;
+import mouda.backend.comment.domain.Comment;
+
+@Builder
+public record CommentResponse(
+	Long commentId,
+
+	String nickname,
+
+	String content,
+
+	@JsonFormat(pattern = "yyyy-MM-dd HH:mm")
+	LocalDateTime dateTime,
+
+	List<ChildCommentResponse> childs
+) {
+	public static CommentResponse toResponse(Comment parentComment, List<ChildCommentResponse> childComments) {
+		return CommentResponse.builder()
+			.commentId(parentComment.getId())
+			.nickname(parentComment.getAuthorNickname())
+			.content(parentComment.getContent())
+			.dateTime(parentComment.getCreatedAt())
+			.childs(childComments)
+			.build();
+	}
+}

backend/src/main/java/mouda/backend/comment/exception/CommentErrorMessage.java

@@ -0,0 +1,16 @@
+package mouda.backend.comment.exception;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+@Getter
+@AllArgsConstructor
+public enum CommentErrorMessage {
+
+	CONTENT_NOT_FOUND("댓글 내용이 존재하지 않습니다."),
+	MEMBER_NOT_FOUND("작성자가 존재하지 않습니다."),
+	PARENT_NOT_FOUND("부모 댓글이 존재하지 않습니다."),
+	;
+
+	private final String message;
+}

backend/src/main/java/mouda/backend/comment/exception/CommentException.java

@@ -0,0 +1,12 @@
+package mouda.backend.comment.exception;
+
+import org.springframework.http.HttpStatus;
+
+import mouda.backend.exception.MoudaException;
+
+public class CommentException extends MoudaException {
+
+	public CommentException(HttpStatus httpStatus, CommentErrorMessage commentErrorMessage) {
+		super(httpStatus, commentErrorMessage.getMessage());
+	}
+}

backend/src/main/java/mouda/backend/comment/repository/CommentRepository.java

@@ -0,0 +1,12 @@
+package mouda.backend.comment.repository;
+
+import java.util.List;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+
+import mouda.backend.comment.domain.Comment;
+
+public interface CommentRepository extends JpaRepository<Comment, Long> {
+
+	List<Comment> findAllByMoimIdOrderByCreatedAt(long id);
+}

backend/src/main/java/mouda/backend/moim/controller/MoimController.java

@@ -11,7 +11,10 @@
 
 import jakarta.validation.Valid;
 import lombok.RequiredArgsConstructor;
+import mouda.backend.comment.dto.request.CommentCreateRequest;
 import mouda.backend.common.RestResponse;
+import mouda.backend.config.argumentresolver.LoginMember;
+import mouda.backend.member.domain.Member;
 import mouda.backend.moim.domain.Moim;
 import mouda.backend.moim.dto.request.MoimCreateRequest;
 import mouda.backend.moim.dto.request.MoimJoinRequest;
@@ -65,4 +68,13 @@ public ResponseEntity<Void> deleteMoim(@PathVariable Long moimId) {
 
 		return ResponseEntity.ok().build();
 	}
+
+	@Override
+	@PostMapping("/{moimId}")
+	public ResponseEntity<Void> createComment(@LoginMember Member member, @PathVariable Long moimId,
+		@RequestBody CommentCreateRequest commentCreateRequest) {
+		moimService.createComment(member, moimId, commentCreateRequest);
+
+		return ResponseEntity.ok().build();
+	}
 }

backend/src/main/java/mouda/backend/moim/controller/MoimSwagger.java

@@ -7,7 +7,10 @@
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.responses.ApiResponse;
 import io.swagger.v3.oas.annotations.responses.ApiResponses;
+import mouda.backend.comment.dto.request.CommentCreateRequest;
 import mouda.backend.common.RestResponse;
+import mouda.backend.config.argumentresolver.LoginMember;
+import mouda.backend.member.domain.Member;
 import mouda.backend.moim.dto.request.MoimCreateRequest;
 import mouda.backend.moim.dto.request.MoimJoinRequest;
 import mouda.backend.moim.dto.response.MoimDetailsFindResponse;
@@ -44,4 +47,11 @@ public interface MoimSwagger {
 		@ApiResponse(responseCode = "200", description = "모임 삭제 성공!"),
 	})
 	ResponseEntity<Void> deleteMoim(@PathVariable Long moimId);
+
+	@Operation(summary = "댓글 작성", description = "해당하는 id의 모임에 댓글을 생성한다.")
+	@ApiResponses({
+		@ApiResponse(responseCode = "200", description = "댓글 생성 성공!")
+	})
+	ResponseEntity<Void> createComment(@LoginMember Member member, @PathVariable Long moimId,
+		@RequestBody CommentCreateRequest commentCreateRequest);
 }

backend/src/main/java/mouda/backend/moim/dto/response/MoimDetailsFindResponse.java

@@ -5,6 +5,7 @@
 import java.util.List;
 
 import lombok.Builder;
+import mouda.backend.comment.dto.response.CommentResponse;
 import mouda.backend.moim.domain.Moim;
 
 @Builder
@@ -17,10 +18,12 @@ public record MoimDetailsFindResponse(
 	int maxPeople,
 	String authorNickname,
 	String description,
-	List<String> participants
+	List<String> participants,
+	List<CommentResponse> comments
 ) {
 
-	public static MoimDetailsFindResponse toResponse(Moim moim, List<String> participants) {
+	public static MoimDetailsFindResponse toResponse(Moim moim, List<String> participants,
+		List<CommentResponse> comments) {
 		return MoimDetailsFindResponse.builder()
 			.title(moim.getTitle())
 			.date(moim.getDate())
@@ -30,6 +33,7 @@ public static MoimDetailsFindResponse toResponse(Moim moim, List<String> partici
 			.maxPeople(moim.getMaxPeople())
 			.description(moim.getDescription())
 			.participants(participants)
+			.comments(comments)
 			.build();
 	}
 }

backend/src/main/java/mouda/backend/moim/service/MoimService.java

@@ -1,12 +1,22 @@
 package mouda.backend.moim.service;
 
+import static java.util.stream.Collectors.*;
+
 import java.util.List;
+import java.util.Map;
 
 import org.springframework.http.HttpStatus;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
 import lombok.RequiredArgsConstructor;
+import mouda.backend.comment.domain.Comment;
+import mouda.backend.comment.dto.request.CommentCreateRequest;
+import mouda.backend.comment.dto.response.ChildCommentResponse;
+import mouda.backend.comment.dto.response.CommentResponse;
+import mouda.backend.comment.exception.CommentErrorMessage;
+import mouda.backend.comment.exception.CommentException;
+import mouda.backend.comment.repository.CommentRepository;
 import mouda.backend.member.domain.Member;
 import mouda.backend.member.repository.MemberRepository;
 import mouda.backend.moim.domain.Moim;
@@ -28,6 +38,8 @@ public class MoimService {
 
 	private final MemberRepository memberRepository;
 
+	private final CommentRepository commentRepository;
+
 	public Moim createMoim(MoimCreateRequest moimCreateRequest) {
 		Member author = new Member(moimCreateRequest.authorNickname());
 		Moim moim = moimRepository.save(moimCreateRequest.toEntity());
@@ -59,7 +71,23 @@ public MoimDetailsFindResponse findMoimDetails(long id) {
 			.map(Member::getNickname)
 			.toList();
 
-		return MoimDetailsFindResponse.toResponse(moim, participants);
+		List<Comment> comments = commentRepository.findAllByMoimIdOrderByCreatedAt(id);
+		Map<Long, List<Comment>> childComments = comments.stream()
+			.filter(Comment::isChild)
+			.collect(groupingBy(Comment::getParentId));
+
+		List<CommentResponse> commentResponses = comments.stream()
+			.filter(Comment::isParent)
+			.map(comment -> CommentResponse.toResponse(comment, findChildComments(comment, childComments)))
+			.toList();
+
+		return MoimDetailsFindResponse.toResponse(moim, participants, commentResponses);
+	}
+
+	private List<ChildCommentResponse> findChildComments(Comment comment, Map<Long, List<Comment>> childComments) {
+		return childComments.getOrDefault(comment.getId(), List.of()).stream()
+			.map(ChildCommentResponse::toResponse)
+			.toList();
 	}
 
 	public void joinMoim(MoimJoinRequest moimJoinRequest) {
@@ -84,4 +112,17 @@ public void deleteMoim(long id) {
 
 		moimRepository.delete(moim);
 	}
+
+	public void createComment(Member member, Long moimId, CommentCreateRequest commentCreateRequest) {
+		Moim moim = moimRepository.findById(moimId).orElseThrow(
+			() -> new MoimException(HttpStatus.NOT_FOUND, MoimErrorMessage.NOT_FOUND)
+		);
+
+		Long parentId = commentCreateRequest.parentId();
+		if (parentId != null && !commentRepository.existsById(parentId)) {
+			throw new CommentException(HttpStatus.BAD_REQUEST, CommentErrorMessage.PARENT_NOT_FOUND);
+		}
+
+		commentRepository.save(commentCreateRequest.toEntity(moim, member));
+	}
 }