WeGo-Together · Be-HinD · Jan 3, 2026 · Jan 3, 2026 · Jan 3, 2026 · Jan 3, 2026
diff --git a/src/main/java/team/wego/wegobackend/chat/application/dto/response/ChatRoomItemResponse.java b/src/main/java/team/wego/wegobackend/chat/application/dto/response/ChatRoomItemResponse.java
@@ -8,6 +8,7 @@ public record ChatRoomItemResponse(
         Long chatRoomId,
         ChatType chatType,
         String chatRoomName,
+        String thumbnail,
         Long groupId,
         int participantCount,
         LastMessageResponse lastMessage,
@@ -17,6 +18,7 @@ public record ChatRoomItemResponse(
     public static ChatRoomItemResponse of(
             ChatRoom chatRoom,
             String chatRoomName,
+            String thumbnail,
             int participantCount,
             LastMessageResponse lastMessage,
             int unreadCount
@@ -25,6 +27,7 @@ public static ChatRoomItemResponse of(
                 chatRoom.getId(),
                 chatRoom.getChatType(),
                 chatRoomName,
+                thumbnail,
                 chatRoom.getGroup() != null ? chatRoom.getGroup().getId() : null,
                 participantCount,
                 lastMessage,

diff --git a/src/main/java/team/wego/wegobackend/chat/application/dto/response/ChatRoomResponse.java b/src/main/java/team/wego/wegobackend/chat/application/dto/response/ChatRoomResponse.java
@@ -9,6 +9,7 @@ public record ChatRoomResponse(
         Long chatRoomId,
         ChatType chatType,
         String chatRoomName,
+        String thumbnail,
         Long groupId,
         int participantCount,
         List<ParticipantResponse> participants,
@@ -18,12 +19,14 @@ public record ChatRoomResponse(
     public static ChatRoomResponse of(
             ChatRoom chatRoom,
             String chatRoomName,
+            String thumbnail,
             List<ParticipantResponse> participants
     ) {
         return new ChatRoomResponse(
                 chatRoom.getId(),
                 chatRoom.getChatType(),
                 chatRoomName,
+                thumbnail,
                 chatRoom.getGroup() != null ? chatRoom.getGroup().getId() : null,
                 participants.size(),
                 participants,

diff --git a/src/main/java/team/wego/wegobackend/chat/application/dto/response/ParticipantResponse.java b/src/main/java/team/wego/wegobackend/chat/application/dto/response/ParticipantResponse.java
@@ -10,15 +10,17 @@ public record ParticipantResponse(
         String nickName,
         String profileImage,
         ParticipantStatus status,
+        boolean isOwner,
         LocalDateTime joinedAt
 ) {
-    public static ParticipantResponse from(ChatParticipant participant) {
+    public static ParticipantResponse from(ChatParticipant participant, boolean isOwner) {
         return new ParticipantResponse(
                 participant.getId(),
                 participant.getUser().getId(),
                 participant.getUser().getNickName(),
                 participant.getUser().getProfileImage(),
                 participant.getStatus(),
+                isOwner,
                 participant.getJoinedAt()
         );
     }

diff --git a/src/main/java/team/wego/wegobackend/chat/application/listener/ChatEventListener.java b/src/main/java/team/wego/wegobackend/chat/application/listener/ChatEventListener.java
@@ -9,7 +9,9 @@
 import team.wego.wegobackend.chat.config.ChatProperties;
 import team.wego.wegobackend.chat.domain.entity.JoinType;
 import team.wego.wegobackend.group.v2.application.event.GroupCreatedEvent;
+import team.wego.wegobackend.group.v2.application.event.GroupJoinApprovedEvent;
 import team.wego.wegobackend.group.v2.application.event.GroupJoinedEvent;
+import team.wego.wegobackend.group.v2.application.event.GroupJoinKickedEvent;
 import team.wego.wegobackend.group.v2.application.event.GroupLeftEvent;
 
 @Component
@@ -68,6 +70,34 @@ public void handleGroupJoined(GroupJoinedEvent event) {
         }
     }
 
+    /**
+     * 모임 참여 승인 시 채팅방 자동 참여 (승인제 모임)
+     */
+    @EventListener
+    @Async
+    public void handleGroupJoinApproved(GroupJoinApprovedEvent event) {
+        log.info("모임 참여 승인 이벤트 수신 - groupId: {}, targetUserId: {}",
+                event.groupId(), event.targetUserId());
+
+        if (!chatProperties.getAutoJoin().isEnabled()) {
+            log.debug("자동 참여 비활성화 - groupId: {}", event.groupId());
+            return;
+        }
+
+        try {
+            chatRoomService.joinChatRoomByGroup(
+                    event.groupId(),
+                    event.targetUserId(),
+                    JoinType.AUTO
+            );
+            log.info("채팅방 자동 참여 완료 (승인) - groupId: {}, userId: {}",
+                    event.groupId(), event.targetUserId());
+        } catch (Exception e) {
+            log.error("채팅방 자동 참여 실패 (승인) - groupId: {}, userId: {}",
+                    event.groupId(), event.targetUserId(), e);
+        }
+    }
+
     /**
      * 모임 퇴장 시 채팅방 퇴장 처리 (선택 사항)
      */
@@ -89,4 +119,26 @@ public void handleGroupLeft(GroupLeftEvent event) {
                     event.groupId(), event.leaverUserId(), e);
         }
     }
+
+    /**
+     * 모임 추방 시 채팅방 퇴장 처리
+     */
+    @EventListener
+    @Async
+    public void handleGroupKicked(GroupJoinKickedEvent event) {
+        log.info("모임 추방 이벤트 수신 - groupId: {}, targetUserId: {}",
+                event.groupId(), event.targetUserId());
+
+        try {
+            chatRoomService.leaveChatRoomByGroup(
+                    event.groupId(),
+                    event.targetUserId()
+            );
+            log.info("채팅방 추방 처리 완료 - groupId: {}, userId: {}",
+                    event.groupId(), event.targetUserId());
+        } catch (Exception e) {
+            log.error("채팅방 추방 처리 실패 - groupId: {}, userId: {}",
+                    event.groupId(), event.targetUserId(), e);
+        }
+    }
 }
diff --git a/src/main/java/team/wego/wegobackend/chat/application/service/ChatRoomService.java b/src/main/java/team/wego/wegobackend/chat/application/service/ChatRoomService.java
@@ -1,5 +1,6 @@
 package team.wego.wegobackend.chat.application.service;
 
+import java.util.Comparator;
 import java.util.List;
 import java.util.stream.Collectors;
 import lombok.RequiredArgsConstructor;
@@ -24,7 +25,10 @@
 import team.wego.wegobackend.chat.domain.repository.ChatMessageRepository;
 import team.wego.wegobackend.chat.domain.repository.ChatParticipantRepository;
 import team.wego.wegobackend.chat.domain.repository.ChatRoomRepository;
+import team.wego.wegobackend.group.v2.domain.entity.GroupImageV2;
+import team.wego.wegobackend.group.v2.domain.entity.GroupImageV2VariantType;
 import team.wego.wegobackend.group.v2.domain.entity.GroupV2;
+import team.wego.wegobackend.group.v2.domain.repository.GroupImageV2Repository;
 import team.wego.wegobackend.group.v2.domain.repository.GroupV2Repository;
 import team.wego.wegobackend.user.domain.User;
 import team.wego.wegobackend.user.repository.UserRepository;
@@ -40,6 +44,7 @@ public class ChatRoomService {
     private final ChatMessageRepository chatMessageRepository;
     private final UserRepository userRepository;
     private final GroupV2Repository groupV2Repository;
+    private final GroupImageV2Repository groupImageV2Repository;
 
     /**
      * 내 채팅방 목록 조회
@@ -49,6 +54,10 @@ public ChatRoomListResponse getMyChatRooms(Long userId) {
 
         List<ChatRoomItemResponse> items = chatRooms.stream()
                 .map(chatRoom -> buildChatRoomItem(chatRoom, userId))
+                .sorted(Comparator.comparing(
+                    item -> item.lastMessage() != null ? item.lastMessage().timestamp() : null, //Group 채팅의 경우 lastMessage가 비어있는 경우 존재 -> NPE 처리
+                    Comparator.nullsLast(Comparator.reverseOrder())  // null 처리 + 최신순
+                ))
                 .collect(Collectors.toList());
 
         return ChatRoomListResponse.from(items);
@@ -61,15 +70,17 @@ public ChatRoomResponse getChatRoom(Long userId, Long roomId) {
         ChatRoom chatRoom = findChatRoomById(roomId);
         validateParticipant(chatRoom.getId(), userId);
 
+        Long hostId = chatRoom.getHostId();
         List<ParticipantResponse> participants = chatParticipantRepository
                 .findActiveParticipants(roomId)
                 .stream()
-                .map(ParticipantResponse::from)
+                .map(p -> ParticipantResponse.from(p, isOwner(p, hostId)))
                 .collect(Collectors.toList());
 
         String chatRoomName = resolveChatRoomName(chatRoom, userId);
+        String thumbnail = resolveThumbnail(chatRoom, userId);
 
-        return ChatRoomResponse.of(chatRoom, chatRoomName, participants);
+        return ChatRoomResponse.of(chatRoom, chatRoomName, thumbnail, participants);
     }
 
     /**
@@ -79,10 +90,11 @@ public ParticipantListResponse getParticipants(Long userId, Long roomId) {
         ChatRoom chatRoom = findChatRoomById(roomId);
         validateParticipant(chatRoom.getId(), userId);
 
+        Long hostId = chatRoom.getHostId();
         List<ParticipantResponse> participants = chatParticipantRepository
                 .findActiveParticipants(roomId)
                 .stream()
-                .map(ParticipantResponse::from)
+                .map(p -> ParticipantResponse.from(p, isOwner(p, hostId)))
                 .collect(Collectors.toList());
 
         return ParticipantListResponse.of(roomId, participants);
@@ -268,6 +280,7 @@ private void validateHost(ChatRoom chatRoom, Long userId) {
 
     private ChatRoomItemResponse buildChatRoomItem(ChatRoom chatRoom, Long userId) {
         String chatRoomName = resolveChatRoomName(chatRoom, userId);
+        String thumbnail = resolveThumbnail(chatRoom, userId);
         int participantCount = chatParticipantRepository.countActiveParticipants(chatRoom.getId());
 
         LastMessageResponse lastMessage = chatMessageRepository.findLatestByChatRoomId(chatRoom.getId())
@@ -279,19 +292,21 @@ private ChatRoomItemResponse buildChatRoomItem(ChatRoom chatRoom, Long userId) {
 
         int unreadCount = calculateUnreadCount(chatRoom.getId(), userId);
 
-        return ChatRoomItemResponse.of(chatRoom, chatRoomName, participantCount, lastMessage, unreadCount);
+        return ChatRoomItemResponse.of(chatRoom, chatRoomName, thumbnail, participantCount, lastMessage, unreadCount);
     }
 
     private ChatRoomResponse buildChatRoomResponse(ChatRoom chatRoom, Long userId) {
         String chatRoomName = resolveChatRoomName(chatRoom, userId);
+        String thumbnail = resolveThumbnail(chatRoom, userId);
 
+        Long hostId = chatRoom.getHostId();
         List<ParticipantResponse> participants = chatParticipantRepository
                 .findActiveParticipants(chatRoom.getId())
                 .stream()
-                .map(ParticipantResponse::from)
+                .map(p -> ParticipantResponse.from(p, isOwner(p, hostId)))
                 .collect(Collectors.toList());
 
-        return ChatRoomResponse.of(chatRoom, chatRoomName, participants);
+        return ChatRoomResponse.of(chatRoom, chatRoomName, thumbnail, participants);
     }
 
     private String resolveChatRoomName(ChatRoom chatRoom, Long userId) {
@@ -308,6 +323,39 @@ private String resolveChatRoomName(ChatRoom chatRoom, Long userId) {
                 .orElse("알 수 없음");
     }
 
+    private String resolveThumbnail(ChatRoom chatRoom, Long userId) {
+        if (chatRoom.getChatType() == ChatType.GROUP && chatRoom.getGroup() != null) {
+            // 그룹 채팅: 그룹의 첫 번째 이미지의 THUMBNAIL_100_100 variant
+            List<GroupImageV2> images = groupImageV2Repository
+                    .findAllByGroupIdWithVariants(chatRoom.getGroup().getId());
+
+            if (images.isEmpty()) {
+                return null;
+            }
+
+            return images.get(0).getVariants().stream()
+                    .filter(v -> v.getType() == GroupImageV2VariantType.THUMBNAIL_100_100)
+                    .findFirst()
+                    .map(v -> v.getImageUrl())
+                    .orElse(null);
+        }
+
+        // DM인 경우 상대방 프로필 이미지 반환
+        return chatParticipantRepository.findActiveParticipants(chatRoom.getId())
+                .stream()
+                .filter(p -> !p.getUser().getId().equals(userId))
+                .findFirst()
+                .map(p -> p.getUser().getProfileImage())
+                .orElse(null);
+    }
+
+    private boolean isOwner(ChatParticipant participant, Long hostId) {
+        if (hostId == null) {
+            return false;
+        }
+        return participant.getUser().getId().equals(hostId);
+    }
+
     private int calculateUnreadCount(Long roomId, Long userId) {
         return chatParticipantRepository.findByChatRoomIdAndUserId(roomId, userId)
                 .filter(ChatParticipant::isActive)

diff --git a/src/main/java/team/wego/wegobackend/chat/config/StompChannelInterceptor.java b/src/main/java/team/wego/wegobackend/chat/config/StompChannelInterceptor.java
@@ -53,6 +53,8 @@ public Message<?> preSend(Message<?> message, MessageChannel channel) {
             }
         }
 
+        //TODO: StompCommand.SUBSCRIBE 분기 처리 로직 추가 (그룹 채팅 참여 검증 로직)
+
         return message;
     }
 

diff --git a/src/main/java/team/wego/wegobackend/chat/domain/entity/ChatRoom.java b/src/main/java/team/wego/wegobackend/chat/domain/entity/ChatRoom.java
@@ -22,6 +22,7 @@
 import lombok.NoArgsConstructor;
 import team.wego.wegobackend.common.entity.BaseTimeEntity;
 import team.wego.wegobackend.group.v2.domain.entity.GroupV2;
+import team.wego.wegobackend.user.domain.User;
 
 @Entity
 @Table(name = "chat_room")
@@ -87,6 +88,20 @@ public boolean isDmChat() {
         return chatType == ChatType.DM;
     }
 
+    public boolean isHost(User user) {
+        if (!isGroupChat() || group == null) {
+            return false;
+        }
+        return group.getHost().getId().equals(user.getId());
+    }
+
+    public Long getHostId() {
+        if (!isGroupChat() || group == null) {
+            return null;
+        }
+        return group.getHost().getId();
+    }
+
     public void addParticipant(ChatParticipant participant) {
         this.participants.add(participant);
         participant.assignToChatRoom(this);
@@ -96,4 +111,5 @@ public void addMessage(ChatMessage message) {
         this.messages.add(message);
         message.assignToChatRoom(this);
     }
+
 }
diff --git a/...main/java/team/wego/wegobackend/group/v2/application/dto/response/GetGroupV2Response.java b/...main/java/team/wego/wegobackend/group/v2/application/dto/response/GetGroupV2Response.java
@@ -35,14 +35,16 @@ public record GetGroupV2Response(
         LocalDateTime createdAt,
         LocalDateTime updatedAt,
         MyMembership myMembership,            // 로그인 아니면 null
-        List<JoinedMember> joinedMembers      // Host면 전체, 아니면 ATTEND만
+        List<JoinedMember> joinedMembers,     // Host면 전체, 아니면 ATTEND만
+        Long chatRoomId                       // 채팅방 참여를 위한 ID
 ) {
 
     public static GetGroupV2Response of(
             GroupV2 group,
             List<GroupImageV2> images,
             List<GroupUserV2> users,
-            Long userIdOrNull
+            Long userIdOrNull,
+            Long chatRoomId
     ) {
         // 태그
         List<String> tagNames = group.getGroupTags().stream()
@@ -106,7 +108,8 @@ public static GetGroupV2Response of(
                 group.getCreatedAt(),
                 group.getUpdatedAt(),
                 myMembership,
-                joinedMembers
+                joinedMembers,
+                chatRoomId
         );
     }
 

diff --git a/src/main/java/team/wego/wegobackend/group/v2/application/service/GroupV2Service.java b/src/main/java/team/wego/wegobackend/group/v2/application/service/GroupV2Service.java
@@ -287,6 +287,8 @@ public GetGroupV2Response getGroup(Long userId, Long groupId) {
         List<GroupImageV2> images = groupImageV2Repository.findAllByGroupIdWithVariants(groupId);
         List<GroupUserV2> users = groupUserV2Repository.findAllByGroupIdWithUser(groupId);
 
-        return GetGroupV2Response.of(group, images, users, userId);
+        Long chatRoomId = group.getChatRoom() != null ? group.getChatRoom().getId() : null;
+
+        return GetGroupV2Response.of(group, images, users, userId, chatRoomId);
     }
 }
diff --git a/src/main/java/team/wego/wegobackend/user/domain/User.java b/src/main/java/team/wego/wegobackend/user/domain/User.java
@@ -85,9 +85,11 @@ public class User extends BaseTimeEntity {
     @Column(name = "provider")
     private ProviderType provider;
 
+    @Builder.Default
     @OneToMany(mappedBy = "follower")
     private List<Follow> followings = new ArrayList<>();
 
+    @Builder.Default
     @OneToMany(mappedBy = "followee")
     private List<Follow> followers = new ArrayList<>();
 
@@ -168,7 +170,7 @@ public void updateNotificationEnabled(Boolean flag) {
 
     public void updatedeleted(Boolean flag) {
         this.deleted = flag;
-    }
+    }   //HARD DELETE로 변경
 
     public void updateMbti(String mbti) {
         this.mbti = mbti;
-Original file line number
+Diff line change
@@ Expand Up @@
                 }
             }
+            //TODO: StompCommand.SUBSCRIBE 분기 처리 로직 추가 (그룹 채팅 참여 검증 로직)
             return message;
         }
@@ Expand Down @@