refactor: chat 도메인 리팩토링

src/main/java/gg/agit/konect/domain/chat/controller/ChatApi.java

@@ -13,7 +13,7 @@
 import gg.agit.konect.domain.chat.dto.ChatMessagesResponse;
 import gg.agit.konect.domain.chat.dto.ChatRoomResponse;
 import gg.agit.konect.domain.chat.dto.ChatRoomsResponse;
-import gg.agit.konect.domain.chat.dto.CreateChatRoomRequest;
+import gg.agit.konect.domain.chat.dto.ChatRoomCreateRequest;
 import gg.agit.konect.global.auth.annotation.UserId;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.tags.Tag;
@@ -38,7 +38,7 @@ public interface ChatApi {
         """)
     @PostMapping("/rooms")
     ResponseEntity<ChatRoomResponse> createOrGetChatRoom(
-        @Valid @RequestBody CreateChatRoomRequest request,
+        @Valid @RequestBody ChatRoomCreateRequest request,
         @UserId Integer userId
     );
 
@@ -52,7 +52,9 @@ ResponseEntity<ChatRoomResponse> createOrGetChatRoom(
         - 최근 메시지가 있는 순서대로 정렬됩니다.
         """)
     @GetMapping("/rooms")
-    ResponseEntity<ChatRoomsResponse> getChatRooms(@UserId Integer userId);
+    ResponseEntity<ChatRoomsResponse> getChatRooms(
+        @UserId Integer userId
+    );
 
     @Operation(summary = "문의하기 메시지 리스트를 조회한다.", description = """
         ## 설명

src/main/java/gg/agit/konect/domain/chat/controller/ChatController.java

@@ -14,8 +14,8 @@
 import gg.agit.konect.domain.chat.dto.ChatMessagesResponse;
 import gg.agit.konect.domain.chat.dto.ChatRoomResponse;
 import gg.agit.konect.domain.chat.dto.ChatRoomsResponse;
-import gg.agit.konect.domain.chat.dto.CreateChatRoomRequest;
-import gg.agit.konect.domain.chat.service.ChatRoomService;
+import gg.agit.konect.domain.chat.dto.ChatRoomCreateRequest;
+import gg.agit.konect.domain.chat.service.ChatService;
 import gg.agit.konect.global.auth.annotation.UserId;
 import jakarta.validation.Valid;
 import lombok.RequiredArgsConstructor;
@@ -25,20 +25,22 @@
 @RequestMapping("/chats")
 public class ChatController implements ChatApi {
 
-    private final ChatRoomService chatRoomService;
+    private final ChatService chatService;
 
     @PostMapping("/rooms")
     public ResponseEntity<ChatRoomResponse> createOrGetChatRoom(
-        @Valid @RequestBody CreateChatRoomRequest request,
+        @Valid @RequestBody ChatRoomCreateRequest request,
         @UserId Integer userId
     ) {
-        ChatRoomResponse response = chatRoomService.createOrGetChatRoom(userId, request);
+        ChatRoomResponse response = chatService.createOrGetChatRoom(userId, request);
         return ResponseEntity.ok(response);
     }
 
     @GetMapping("/rooms")
-    public ResponseEntity<ChatRoomsResponse> getChatRooms(@UserId Integer userId) {
-        ChatRoomsResponse response = chatRoomService.getChatRooms(userId);
+    public ResponseEntity<ChatRoomsResponse> getChatRooms(
+        @UserId Integer userId
+    ) {
+        ChatRoomsResponse response = chatService.getChatRooms(userId);
         return ResponseEntity.ok(response);
     }
 
@@ -49,7 +51,7 @@ public ResponseEntity<ChatMessagesResponse> getChatRoomMessages(
         @PathVariable(value = "chatRoomId") Integer chatRoomId,
         @UserId Integer userId
     ) {
-        ChatMessagesResponse response = chatRoomService.getChatRoomMessages(userId, chatRoomId, page, limit);
+        ChatMessagesResponse response = chatService.getChatRoomMessages(userId, chatRoomId, page, limit);
         return ResponseEntity.ok(response);
     }
 
@@ -59,7 +61,7 @@ public ResponseEntity<ChatMessageResponse> sendMessage(
         @Valid @RequestBody ChatMessageSendRequest request,
         @UserId Integer userId
     ) {
-        ChatMessageResponse response = chatRoomService.sendMessage(userId, chatRoomId, request);
+        ChatMessageResponse response = chatService.sendMessage(userId, chatRoomId, request);
         return ResponseEntity.ok(response);
     }
 }

src/main/java/gg/agit/konect/domain/chat/dto/CreateChatRoomRequest.java → src/main/java/gg/agit/konect/domain/chat/dto/ChatRoomCreateRequest.java

@@ -5,7 +5,7 @@
 import io.swagger.v3.oas.annotations.media.Schema;
 import jakarta.validation.constraints.NotNull;
 
-public record CreateChatRoomRequest(
+public record ChatRoomCreateRequest(
     @NotNull(message = "동아리 ID는 필수입니다.")
     @Schema(description = "동아리 ID", example = "1", requiredMode = REQUIRED)
     Integer clubId

src/main/java/gg/agit/konect/domain/chat/dto/ChatRoomsResponse.java

@@ -5,6 +5,7 @@
 
 import java.time.LocalDateTime;
 import java.util.List;
+import java.util.Map;
 
 import com.fasterxml.jackson.annotation.JsonFormat;
 
@@ -36,23 +37,27 @@ public record InnerChatRoomResponse(
         @Schema(description = "읽지 않은 메시지 개수", example = "12", requiredMode = REQUIRED)
         Integer unreadCount
     ) {
-        public static InnerChatRoomResponse from(ChatRoom chatRoom, User currentUser) {
+        public static InnerChatRoomResponse from(
+            ChatRoom chatRoom, User currentUser, Map<Integer, Integer> unreadCountMap
+        ) {
             User chatPartner = chatRoom.getChatPartner(currentUser);
 
             return new InnerChatRoomResponse(
                 chatRoom.getId(),
                 chatPartner.getName(),
                 chatPartner.getImageUrl(),
                 chatRoom.getLastMessageContent(),
-                chatRoom.getLastMessageTime(),
-                chatRoom.getUnreadCount(currentUser.getId())
+                chatRoom.getLastMessageSentAt(),
+                unreadCountMap.getOrDefault(chatRoom.getId(), 0)
             );
         }
     }
 
-    public static ChatRoomsResponse from(List<ChatRoom> chatRooms, User currentUser) {
+    public static ChatRoomsResponse from(
+        List<ChatRoom> chatRooms, User currentUser, Map<Integer, Integer> unreadCountMap
+    ) {
         return new ChatRoomsResponse(chatRooms.stream()
-            .map(chatRoom -> InnerChatRoomResponse.from(chatRoom, currentUser))
+            .map(chatRoom -> InnerChatRoomResponse.from(chatRoom, currentUser, unreadCountMap))
             .toList());
     }
 }

src/main/java/gg/agit/konect/domain/chat/dto/UnreadMessageCount.java

@@ -0,0 +1,8 @@
+package gg.agit.konect.domain.chat.dto;
+
+public record UnreadMessageCount(
+    Integer chatRoomId,
+    Long unreadCount
+) {
+
+}

src/main/java/gg/agit/konect/domain/chat/model/ChatMessage.java

@@ -76,7 +76,7 @@ public static ChatMessage of(ChatRoom chatRoom, User sender, User receiver, Stri
             .build();
     }
 
-    public Boolean isSentBy(Integer userId) {
+    public boolean isSentBy(Integer userId) {
         return sender.getId().equals(userId);
     }
 

src/main/java/gg/agit/konect/domain/chat/model/ChatRoom.java

@@ -1,23 +1,22 @@
 package gg.agit.konect.domain.chat.model;
 
+import static gg.agit.konect.global.code.ApiResponseCode.CANNOT_CREATE_CHAT_ROOM_WITH_SELF;
+import static gg.agit.konect.global.code.ApiResponseCode.FORBIDDEN_CHAT_ROOM_ACCESS;
 import static jakarta.persistence.FetchType.LAZY;
 import static jakarta.persistence.GenerationType.IDENTITY;
 import static lombok.AccessLevel.PROTECTED;
 
 import java.time.LocalDateTime;
-import java.util.ArrayList;
-import java.util.Comparator;
-import java.util.List;
 
 import gg.agit.konect.domain.user.model.User;
+import gg.agit.konect.global.exception.CustomException;
 import gg.agit.konect.global.model.BaseEntity;
 import jakarta.persistence.Column;
 import jakarta.persistence.Entity;
 import jakarta.persistence.GeneratedValue;
 import jakarta.persistence.Id;
 import jakarta.persistence.JoinColumn;
 import jakarta.persistence.ManyToOne;
-import jakarta.persistence.OneToMany;
 import jakarta.persistence.Table;
 import lombok.Builder;
 import lombok.Getter;
@@ -34,6 +33,12 @@ public class ChatRoom extends BaseEntity {
     @Column(name = "id", nullable = false, updatable = false, unique = true)
     private Integer id;
 
+    @Column(name = "last_message_content", columnDefinition = "TEXT")
+    private String lastMessageContent;
+
+    @Column(name = "last_message_sent_at")
+    private LocalDateTime lastMessageSentAt;
+
     @ManyToOne(fetch = LAZY)
     @JoinColumn(name = "sender_id")
     private User sender;
@@ -42,9 +47,6 @@ public class ChatRoom extends BaseEntity {
     @JoinColumn(name = "receiver_id")
     private User receiver;
 
-    @OneToMany(mappedBy = "chatRoom", fetch = LAZY)
-    private List<ChatMessage> chatMessages = new ArrayList<>();
-
     @Builder
     private ChatRoom(Integer id, User sender, User receiver) {
         this.id = id;
@@ -53,40 +55,35 @@ private ChatRoom(Integer id, User sender, User receiver) {
     }
 
     public static ChatRoom of(User sender, User receiver) {
+        validateIsNotSameParticipant(sender, receiver);
         return ChatRoom.builder()
             .sender(sender)
             .receiver(receiver)
             .build();
     }
 
-    public User getChatPartner(User currentUser) {
-        return sender.getId().equals(currentUser.getId()) ? receiver : sender;
+    public static void validateIsNotSameParticipant(User sender, User receiver) {
+        if (sender.getId().equals(receiver.getId())) {
+            throw CustomException.of(CANNOT_CREATE_CHAT_ROOM_WITH_SELF);
+        }
     }
 
-    public boolean isParticipant(Integer userId) {
-        return sender.getId().equals(userId) || receiver.getId().equals(userId);
+    public void validateIsParticipant(Integer userId) {
+        if (!isParticipant(userId)) {
+            throw CustomException.of(FORBIDDEN_CHAT_ROOM_ACCESS);
+        }
     }
 
-    public ChatMessage getLastMessage() {
-        return chatMessages.stream()
-            .max(Comparator.comparing(BaseEntity::getCreatedAt))
-            .orElse(null);
-    }
-
-    public String getLastMessageContent() {
-        ChatMessage lastMessage = getLastMessage();
-        return lastMessage != null ? lastMessage.getContent() : null;
+    public boolean isParticipant(Integer userId) {
+        return sender.getId().equals(userId) || receiver.getId().equals(userId);
     }
 
-    public LocalDateTime getLastMessageTime() {
-        ChatMessage lastMessage = getLastMessage();
-        return lastMessage != null ? lastMessage.getCreatedAt() : null;
+    public User getChatPartner(User currentUser) {
+        return sender.getId().equals(currentUser.getId()) ? receiver : sender;
     }
 
-    public Integer getUnreadCount(Integer userId) {
-        return (int)chatMessages.stream()
-            .filter(message -> message.getReceiver().getId().equals(userId))
-            .filter(message -> !message.getIsRead())
-            .count();
+    public void updateLastMessage(String lastMessageContent, LocalDateTime lastMessageSentAt) {
+        this.lastMessageContent = lastMessageContent;
+        this.lastMessageSentAt = lastMessageSentAt;
     }
 }

src/main/java/gg/agit/konect/domain/chat/repository/ChatMessageRepository.java

@@ -9,12 +9,29 @@
 import org.springframework.data.repository.Repository;
 import org.springframework.data.repository.query.Param;
 
+import gg.agit.konect.domain.chat.dto.UnreadMessageCount;
 import gg.agit.konect.domain.chat.model.ChatMessage;
 
 public interface ChatMessageRepository extends Repository<ChatMessage, Integer> {
 
     ChatMessage save(ChatMessage chatMessage);
 
+    @Query("""
+        SELECT new gg.agit.konect.domain.chat.dto.UnreadMessageCount(
+            cm.chatRoom.id,
+            COUNT(cm)
+        )
+        FROM ChatMessage cm
+        WHERE cm.chatRoom.id IN :chatRoomIds
+        AND cm.receiver.id = :receiverId
+        AND cm.isRead = false
+        GROUP BY cm.chatRoom.id
+        """)
+    List<UnreadMessageCount> countUnreadMessagesByChatRoomIdsAndUserId(
+        @Param("chatRoomIds") List<Integer> chatRoomIds,
+        @Param("receiverId") Integer receiverId
+    );
+
     @Query("""
         SELECT cm
         FROM ChatMessage cm
@@ -31,7 +48,7 @@ public interface ChatMessageRepository extends Repository<ChatMessage, Integer>
         AND cm.receiver.id = :receiverId
         AND cm.isRead = false
         """)
-    List<ChatMessage> findUnreadMessages(
+    List<ChatMessage> findUnreadMessagesByChatRoomIdAndUserId(
         @Param("chatRoomId") Integer chatRoomId,
         @Param("receiverId") Integer receiverId
     );

src/main/java/gg/agit/konect/domain/chat/repository/ChatRoomRepository.java

@@ -19,9 +19,8 @@ public interface ChatRoomRepository extends Repository<ChatRoom, Integer> {
         FROM ChatRoom cr
         JOIN FETCH cr.sender
         JOIN FETCH cr.receiver
-        LEFT JOIN FETCH cr.chatMessages
         WHERE cr.sender.id = :userId OR cr.receiver.id = :userId
-        ORDER BY cr.updatedAt DESC
+        ORDER BY cr.lastMessageSentAt DESC NULLS LAST, cr.id
         """)
     List<ChatRoom> findByUserId(@Param("userId") Integer userId);