유저 동아리 추가 서비스 구현

Mono.when을 사용해 독립적, 병렬적으로 실행하도록 구현

src/main/java/com/example/daemawiki/domain/user/dto/UpdateClubRequest.java

@@ -0,0 +1,6 @@
+package com.example.daemawiki.domain.user.dto;
+
+public record UpdateClubRequest(
+        String club
+) {
+}

src/main/java/com/example/daemawiki/domain/user/service/UpdateClub.java

@@ -0,0 +1,42 @@
+package com.example.daemawiki.domain.user.service;
+
+import com.example.daemawiki.domain.document.component.facade.DocumentFacade;
+import com.example.daemawiki.domain.document.model.DefaultDocument;
+import com.example.daemawiki.domain.document.repository.DocumentRepository;
+import com.example.daemawiki.domain.user.dto.UpdateClubRequest;
+import com.example.daemawiki.domain.user.model.User;
+import com.example.daemawiki.domain.user.repository.UserRepository;
+import com.example.daemawiki.domain.user.service.facade.UserFacade;
+import org.springframework.stereotype.Service;
+import reactor.core.publisher.Mono;
+
+import java.util.Arrays;
+
+@Service
+public class UpdateClub {
+    private final UserFacade userFacade;
+    private final DocumentFacade documentFacade;
+    private final UserRepository userRepository;
+    private final DocumentRepository documentRepository;
+
+    public UpdateClub(UserFacade userFacade, DocumentFacade documentFacade, UserRepository userRepository, DocumentRepository documentRepository) {
+        this.userFacade = userFacade;
+        this.documentFacade = documentFacade;
+        this.userRepository = userRepository;
+        this.documentRepository = documentRepository;
+    }
+
+    public Mono<Void> execute(UpdateClubRequest request) {
+        Mono<User> userMono = userFacade.currentUser()
+                .doOnNext(user -> user.getDetail().setClub(request.club()))
+                .flatMap(userRepository::save);
+
+        Mono<DefaultDocument> documentMono = userMono
+                .flatMap(user -> documentFacade.findDocumentById(user.getDocumentId()))
+                .doOnNext(document -> document.getGroups().add(Arrays.asList("동아리", request.club())))
+                .flatMap(documentRepository::save);
+
+        return Mono.when(userMono, documentMono).then();
+    }
+
+}