채팅 기록 조회 API 개발

src/main/java/com/sofa/linkiving/domain/chat/controller/ChatApi.java

@@ -1,15 +1,22 @@
 package com.sofa.linkiving.domain.chat.controller;
 
+import org.springframework.validation.annotation.Validated;
+
 import com.sofa.linkiving.domain.chat.dto.request.CreateChatReq;
 import com.sofa.linkiving.domain.chat.dto.response.ChatsRes;
 import com.sofa.linkiving.domain.chat.dto.response.CreateChatRes;
+import com.sofa.linkiving.domain.chat.dto.response.MessagesRes;
 import com.sofa.linkiving.domain.member.entity.Member;
 import com.sofa.linkiving.global.common.BaseResponse;
 
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.Parameter;
 import io.swagger.v3.oas.annotations.tags.Tag;
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.Max;
+import jakarta.validation.constraints.Min;
 
+@Validated
 @Tag(name = "Chat", description = """
 	AI 채팅 통합 명세 (HTTP + WebSocket)
 
@@ -27,12 +34,24 @@
 
 	""")
 public interface ChatApi {
+	@Operation(summary = "채팅 기록 조회", description = "채팅 기록을 최신순으로 조회합니다. 무한 스크롤 방식으로 제공됩니다.")
+	BaseResponse<MessagesRes> getMessages(
+		Member member,
+		@Parameter(description = "채팅방 ID") Long chatId,
+		@Parameter(description = "페이징을 위한 마지막 메시지 ID, 첫 조회 시 null") Long lastId,
+
+		@Parameter(description = "페이지 크기")
+		@Min(value = 1, message = "최소 1개 이상 조회해야 합니다.")
+		@Max(value = 50, message = "한 번에 최대 50개까지만 조회할 수 있습니다.")
+		int size
+	);
+
 	@Operation(summary = "채팅방 목록 조회", description = "사용자의 채팅방 목록 정보(채팅방 Id, 제목)을 조회합니다.")
 	BaseResponse<ChatsRes> getChats(Member member);
 
 	@Operation(summary = "새로운 채팅 생성", description = "새로운 채팅을 생성합니다.")
 	BaseResponse<CreateChatRes> createChat(
-		CreateChatReq req,
+		@Valid CreateChatReq req,
 		Member member
 	);
 

src/main/java/com/sofa/linkiving/domain/chat/controller/ChatController.java

@@ -9,17 +9,18 @@
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.RestController;
 
 import com.sofa.linkiving.domain.chat.dto.request.CreateChatReq;
 import com.sofa.linkiving.domain.chat.dto.response.ChatsRes;
 import com.sofa.linkiving.domain.chat.dto.response.CreateChatRes;
+import com.sofa.linkiving.domain.chat.dto.response.MessagesRes;
 import com.sofa.linkiving.domain.chat.facade.ChatFacade;
 import com.sofa.linkiving.domain.member.entity.Member;
 import com.sofa.linkiving.global.common.BaseResponse;
 import com.sofa.linkiving.security.annotation.AuthMember;
 
-import jakarta.validation.Valid;
 import lombok.RequiredArgsConstructor;
 
 @RestController
@@ -37,7 +38,7 @@ public BaseResponse<ChatsRes> getChats(@AuthMember Member member) {
 
 	@Override
 	@PostMapping
-	public BaseResponse<CreateChatRes> createChat(@RequestBody @Valid CreateChatReq req, @AuthMember Member member) {
+	public BaseResponse<CreateChatRes> createChat(@RequestBody CreateChatReq req, @AuthMember Member member) {
 		CreateChatRes res = chatFacade.createChat(req.firstChat(), member);
 		return BaseResponse.success(res, "채팅방 생성 완료");
 	}
@@ -60,4 +61,16 @@ public void sendMessage(@DestinationVariable Long chatId, @Payload String messag
 	public void cancelMessage(@DestinationVariable Long chatId, @AuthMember Member member) {
 		chatFacade.cancelAnswer(chatId, member);
 	}
+
+	@Override
+	@GetMapping("/{chatId}")
+	public BaseResponse<MessagesRes> getMessages(
+		@AuthMember Member member,
+		@PathVariable Long chatId,
+		@RequestParam(required = false) Long lastId,
+		@RequestParam(defaultValue = "20") int size
+	) {
+		MessagesRes res = chatFacade.getMessages(member, chatId, lastId, size);
+		return BaseResponse.success(res, "채팅 기록을 가져오는데 성공했습니다.");
+	}
 }

src/main/java/com/sofa/linkiving/domain/chat/dto/internal/MessageDto.java

@@ -0,0 +1,9 @@
+package com.sofa.linkiving.domain.chat.dto.internal;
+
+import java.util.List;
+
+import com.sofa.linkiving.domain.chat.entity.Message;
+import com.sofa.linkiving.domain.link.dto.internal.LinkDto;
+
+public record MessageDto(Message message, List<LinkDto> linkDtos) {
+}

src/main/java/com/sofa/linkiving/domain/chat/dto/internal/MessagesDto.java

@@ -0,0 +1,9 @@
+package com.sofa.linkiving.domain.chat.dto.internal;
+
+import java.util.List;
+
+public record MessagesDto(
+	List<MessageDto> messageDtos,
+	boolean hasNext
+) {
+}

src/main/java/com/sofa/linkiving/domain/chat/dto/response/MessageRes.java

@@ -0,0 +1,51 @@
+package com.sofa.linkiving.domain.chat.dto.response;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+import com.fasterxml.jackson.annotation.JsonFormat;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.sofa.linkiving.domain.chat.dto.internal.MessageDto;
+import com.sofa.linkiving.domain.chat.entity.Message;
+import com.sofa.linkiving.domain.chat.enums.Sentiment;
+import com.sofa.linkiving.domain.chat.enums.Type;
+import com.sofa.linkiving.domain.link.dto.response.LinkCardRes;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+
+public record MessageRes(
+	@Schema(description = "메시지 ID")
+	Long id,
+
+	@Schema(description = "메시지 내용")
+	String content,
+
+	@Schema(description = "발신자 타입 (USER / AI)")
+	Type type,
+
+	@JsonInclude(JsonInclude.Include.NON_NULL)
+	@Schema(description = "피드백 상태 (AI 메시지인 경우만 포함: LIKE, DISLIKE, NONE)")
+	Sentiment feedback,
+
+	@Schema(description = "메시지 생성 시간", example = "2024-12-31 14:30:00")
+	@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd HH:mm:ss", timezone = "Asia/Seoul")
+	LocalDateTime time,
+
+	@Schema(description = "첨부된 링크 목록")
+	List<LinkCardRes> links
+) {
+	public static MessageRes from(MessageDto messageDto) {
+		Message message = messageDto.message();
+
+		return new MessageRes(
+			message.getId(),
+			message.getContent(),
+			message.getType(),
+			message.getSentimentOrDefault(),
+			message.getCreatedAt(),
+			messageDto.linkDtos().stream()
+				.map(LinkCardRes::from)
+				.toList()
+		);
+	}
+}

src/main/java/com/sofa/linkiving/domain/chat/dto/response/MessagesRes.java

@@ -0,0 +1,34 @@
+package com.sofa.linkiving.domain.chat.dto.response;
+
+import java.util.Collections;
+import java.util.List;
+
+import com.sofa.linkiving.domain.chat.dto.internal.MessageDto;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+
+public record MessagesRes(
+	@Schema(description = "메시지 목록")
+	List<MessageRes> messages,
+
+	@Schema(description = "다음 페이지 존재 여부")
+	boolean hasNext,
+
+	@Schema(description = "마지막 메시지 ID (다음 요청 커서용)")
+	Long lastId
+) {
+	public static MessagesRes of(List<MessageDto> messageDtos, boolean hasNext) {
+		if (messageDtos.isEmpty()) {
+			return new MessagesRes(Collections.emptyList(), hasNext, null);
+		}
+
+		List<MessageRes> responses = messageDtos.stream()
+			.map(MessageRes::from)
+			.toList();
+
+		Long lastId = messageDtos.get(messageDtos.size() - 1).message().getId();
+
+		return new MessagesRes(responses, hasNext, lastId);
+	}
+
+}

src/main/java/com/sofa/linkiving/domain/chat/entity/Message.java

@@ -3,15 +3,17 @@
 import java.util.ArrayList;
 import java.util.List;
 
+import com.sofa.linkiving.domain.chat.enums.Sentiment;
 import com.sofa.linkiving.domain.chat.enums.Type;
+import com.sofa.linkiving.domain.link.entity.Link;
 import com.sofa.linkiving.global.common.BaseEntity;
-import com.sofa.linkiving.global.converter.LongListToStringConverter;
 
 import jakarta.persistence.Column;
-import jakarta.persistence.Convert;
 import jakarta.persistence.Entity;
 import jakarta.persistence.FetchType;
 import jakarta.persistence.JoinColumn;
+import jakarta.persistence.JoinTable;
+import jakarta.persistence.ManyToMany;
 import jakarta.persistence.ManyToOne;
 import jakarta.persistence.OneToOne;
 import jakarta.persistence.Table;
@@ -36,17 +38,29 @@ public class Message extends BaseEntity {
 	@Column(columnDefinition = "text", nullable = false)
 	private String content;
 
-	@Convert(converter = LongListToStringConverter.class)
-	private List<Long> linkIds = new ArrayList<>();
+	@ManyToMany(fetch = FetchType.LAZY)
+	@JoinTable(
+		name = "message_link",
+		joinColumns = @JoinColumn(name = "message_id"),
+		inverseJoinColumns = @JoinColumn(name = "link_id")
+	)
+	private List<Link> links = new ArrayList<>();
 
 	@OneToOne(mappedBy = "message")
 	private Feedback feedback;
 
 	@Builder
-	public Message(Chat chat, Type type, String content, List<Long> linkIds) {
+	public Message(Chat chat, Type type, String content, List<Link> links) {
 		this.chat = chat;
 		this.type = type;
 		this.content = content;
-		this.linkIds = linkIds;
+		this.links = (links != null) ? links : new ArrayList<>();
+	}
+
+	public Sentiment getSentimentOrDefault() {
+		if (this.type != Type.AI) {
+			return null;
+		}
+		return (this.feedback != null) ? this.feedback.getSentiment() : Sentiment.NONE;
 	}
 }

src/main/java/com/sofa/linkiving/domain/chat/enums/Sentiment.java

@@ -10,7 +10,7 @@
 @Getter
 @RequiredArgsConstructor
 public enum Sentiment implements CodeEnum<Integer> {
-	LIKE(0), DISLIKE(1);
+	LIKE(0), DISLIKE(1), NONE(2);
 	private final Integer code;
 
 	@Converter(autoApply = true)

src/main/java/com/sofa/linkiving/domain/chat/facade/ChatFacade.java

@@ -6,8 +6,10 @@
 import org.springframework.transaction.annotation.Transactional;
 
 import com.sofa.linkiving.domain.chat.ai.AiTitleClient;
+import com.sofa.linkiving.domain.chat.dto.internal.MessagesDto;
 import com.sofa.linkiving.domain.chat.dto.response.ChatsRes;
 import com.sofa.linkiving.domain.chat.dto.response.CreateChatRes;
+import com.sofa.linkiving.domain.chat.dto.response.MessagesRes;
 import com.sofa.linkiving.domain.chat.entity.Chat;
 import com.sofa.linkiving.domain.chat.service.ChatService;
 import com.sofa.linkiving.domain.chat.service.FeedbackService;
@@ -25,6 +27,12 @@ public class ChatFacade {
 	private final FeedbackService feedbackService;
 	private final AiTitleClient aiTitleClient;
 
+	public MessagesRes getMessages(Member member, Long chatId, Long lastId, int size) {
+		Chat chat = chatService.getChat(chatId, member);
+		MessagesDto result = messageService.getMessages(chat, lastId, size);
+		return MessagesRes.of(result.messageDtos(), result.hasNext());
+	}
+
 	@Transactional
 	public CreateChatRes createChat(String firstChat, Member member) {
 		String title = aiTitleClient.generateSummary(firstChat);

src/main/java/com/sofa/linkiving/domain/chat/repository/MessageRepository.java

@@ -2,9 +2,11 @@
 
 import java.util.List;
 
+import org.springframework.data.domain.Pageable;
 import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.data.jpa.repository.Modifying;
 import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
 import org.springframework.stereotype.Repository;
 
 import com.sofa.linkiving.domain.chat.entity.Chat;
@@ -16,6 +18,18 @@ public interface MessageRepository extends JpaRepository<Message, Long> {
 	@Query("DELETE FROM Message m WHERE m.chat = :chat")
 	void deleteAllByChat(Chat chat);
 
-	@Query("SELECT m FROM Message m LEFT JOIN FETCH m.feedback WHERE m.chat = :chat")
+	@Query("""
+		SELECT m FROM Message m
+		LEFT JOIN FETCH m.feedback
+		WHERE m.chat = :chat
+		AND (:lastId IS NULL OR m.id < :lastId)
+		ORDER BY m.id DESC
+		""")
+	List<Message> findAllByChatAndCursor(
+		@Param("chat") Chat chat,
+		@Param("lastId") Long lastId,
+		Pageable pageable
+	);
+
 	List<Message> findAllByChat(Chat chat);
 }

src/main/java/com/sofa/linkiving/domain/chat/service/MessageQueryService.java

@@ -2,6 +2,9 @@
 
 import java.util.List;
 
+import org.springframework.data.domain.PageRequest;
+import org.springframework.data.domain.Slice;
+import org.springframework.data.domain.SliceImpl;
 import org.springframework.stereotype.Service;
 
 import com.sofa.linkiving.domain.chat.entity.Chat;
@@ -15,7 +18,16 @@
 public class MessageQueryService {
 	private final MessageRepository messageRepository;
 
-	public List<Message> findAllByChat(Chat chat) {
-		return messageRepository.findAllByChat(chat);
+	public Slice<Message> findAllByChatAndCursor(Chat chat, Long lastId, int size) {
+		PageRequest pageRequest = PageRequest.of(0, size + 1);
+		List<Message> messages = messageRepository.findAllByChatAndCursor(chat, lastId, pageRequest);
+
+		boolean hasNext = false;
+		if (size < messages.size()) {
+			hasNext = true;
+			messages.remove(size);
+		}
+
+		return new SliceImpl<>(messages, pageRequest, hasNext);
 	}
 }