From 76722aee1edd80e829c63f1ec10fe7481cb64973 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=EC=9D=B4=EB=8F=99=ED=9B=88?= <2dh2@naver.com>
Date: Fri, 23 Jan 2026 18:33:31 +0900
Subject: [PATCH] =?UTF-8?q?feat:=20=ED=9A=8C=EC=9B=90=EA=B0=80=EC=9E=85=20?=
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---
 .../user/repository/UserRepository.java       |  3 ++
 .../domain/user/service/UserService.java      | 32 +++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/src/main/java/gg/agit/konect/domain/user/repository/UserRepository.java b/src/main/java/gg/agit/konect/domain/user/repository/UserRepository.java
index 72c0719c..836c70d3 100644
--- a/src/main/java/gg/agit/konect/domain/user/repository/UserRepository.java
+++ b/src/main/java/gg/agit/konect/domain/user/repository/UserRepository.java
@@ -10,6 +10,7 @@
 import gg.agit.konect.global.code.ApiResponseCode;
 import gg.agit.konect.global.exception.CustomException;
 import gg.agit.konect.domain.user.enums.Provider;
+import gg.agit.konect.domain.user.enums.UserRole;
 import gg.agit.konect.domain.user.model.User;
 
 public interface UserRepository extends Repository<User, Integer> {
@@ -22,6 +23,8 @@ public interface UserRepository extends Repository<User, Integer> {
 
     Optional<User> findById(Integer id);
 
+    Optional<User> findFirstByRoleOrderByIdAsc(UserRole role);
+
     default User getById(Integer id) {
         return findById(id).orElseThrow(() ->
             CustomException.of(ApiResponseCode.NOT_FOUND_USER));
diff --git a/src/main/java/gg/agit/konect/domain/user/service/UserService.java b/src/main/java/gg/agit/konect/domain/user/service/UserService.java
index 0a136463..6aedb5ec 100644
--- a/src/main/java/gg/agit/konect/domain/user/service/UserService.java
+++ b/src/main/java/gg/agit/konect/domain/user/service/UserService.java
@@ -10,6 +10,8 @@
 import org.springframework.transaction.annotation.Transactional;
 import org.springframework.util.StringUtils;
 
+import gg.agit.konect.domain.chat.model.ChatMessage;
+import gg.agit.konect.domain.chat.model.ChatRoom;
 import gg.agit.konect.domain.chat.repository.ChatMessageRepository;
 import gg.agit.konect.domain.chat.repository.ChatRoomRepository;
 import gg.agit.konect.domain.club.enums.ClubPositionGroup;
@@ -27,6 +29,7 @@
 import gg.agit.konect.domain.user.dto.UserInfoResponse;
 import gg.agit.konect.domain.user.dto.UserUpdateRequest;
 import gg.agit.konect.domain.user.enums.Provider;
+import gg.agit.konect.domain.user.enums.UserRole;
 import gg.agit.konect.domain.user.model.UnRegisteredUser;
 import gg.agit.konect.domain.user.model.User;
 import gg.agit.konect.domain.user.repository.UnRegisteredUserRepository;
@@ -34,12 +37,16 @@
 import gg.agit.konect.global.code.ApiResponseCode;
 import gg.agit.konect.global.exception.CustomException;
 import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
 
 @Service
+@Slf4j
 @RequiredArgsConstructor
 @Transactional(readOnly = true)
 public class UserService {
 
+    private static final String DEFAULT_WELCOME_MESSAGE = "KONECT에 오신 것을 환영합니다. 궁금한 점이 있으면 언제든 문의해 주세요.";
+
     private final UserRepository userRepository;
     private final UnRegisteredUserRepository unRegisteredUserRepository;
     private final UniversityRepository universityRepository;
@@ -89,11 +96,36 @@ public Integer signup(String email, String providerId, Provider provider, Signup
 
         joinPreMembers(savedUser, university.getId(), request.studentNumber(), request.name());
 
+        sendWelcomeMessage(savedUser);
+
         unRegisteredUserRepository.delete(tempUser);
 
         return savedUser.getId();
     }
 
+    // TODO 추후에 슈퍼 어드민을 만들어 학교가 확장되는 것을 고려해야 함
+    private void sendWelcomeMessage(User newUser) {
+        try {
+            User operator = userRepository.findFirstByRoleOrderByIdAsc(UserRole.ADMIN)
+                .orElse(null);
+
+            if (operator == null) {
+                return;
+            }
+
+            ChatRoom chatRoom = chatRoomRepository.findByTwoUsers(operator.getId(), newUser.getId())
+                .orElseGet(() -> chatRoomRepository.save(ChatRoom.of(operator, newUser)));
+
+            ChatMessage chatMessage = chatMessageRepository.save(
+                ChatMessage.of(chatRoom, operator, newUser, DEFAULT_WELCOME_MESSAGE)
+            );
+
+            chatRoom.updateLastMessage(chatMessage.getContent(), chatMessage.getCreatedAt());
+        } catch (Exception e) {
+            log.warn("회원가입 환영 메시지 전송 실패. userId={}", newUser.getId(), e);
+        }
+    }
+
     private UnRegisteredUser findUnregisteredUser(String email, String providerId, Provider provider) {
         if (StringUtils.hasText(providerId)) {
             if (unRegisteredUserRepository.existsByProviderIdAndProvider(providerId, provider)) {