refactor: 이달의 현황 API lastMonthRank를 스냅샷 단건 조회로 변경 (#405)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: KoSeonJe

src/main/java/ddingdong/ddingdongBE/domain/feed/repository/FeedMonthlyRankingRepository.java

@@ -2,6 +2,7 @@
 
 import ddingdong.ddingdongBE.domain.feed.entity.FeedMonthlyRanking;
 import java.util.List;
+import java.util.Optional;
 import org.springframework.data.jpa.repository.JpaRepository;
 
 public interface FeedMonthlyRankingRepository extends JpaRepository<FeedMonthlyRanking, Long> {
@@ -10,4 +11,10 @@ public interface FeedMonthlyRankingRepository extends JpaRepository<FeedMonthlyR
 
     List<FeedMonthlyRanking> findAllByTargetYearAndTargetMonthAndRanking(
             int targetYear, int targetMonth, int ranking);
+
+    List<FeedMonthlyRanking> findAllByTargetYearAndTargetMonthOrderByRankingAsc(
+            int targetYear, int targetMonth);
+
+    Optional<FeedMonthlyRanking> findByClubIdAndTargetYearAndTargetMonth(
+            Long clubId, int targetYear, int targetMonth);
 }

src/main/java/ddingdong/ddingdongBE/domain/feed/service/GeneralFeedRankingService.java

@@ -2,6 +2,8 @@
 
 import ddingdong.ddingdongBE.domain.club.entity.Club;
 import ddingdong.ddingdongBE.domain.club.service.ClubService;
+import ddingdong.ddingdongBE.domain.feed.entity.FeedMonthlyRanking;
+import ddingdong.ddingdongBE.domain.feed.repository.FeedMonthlyRankingRepository;
 import ddingdong.ddingdongBE.domain.feed.repository.FeedRepository;
 import ddingdong.ddingdongBE.domain.feed.repository.dto.MonthlyFeedRankingDto;
 import ddingdong.ddingdongBE.domain.feed.service.dto.query.ClubFeedRankingQuery;
@@ -24,6 +26,7 @@ public class GeneralFeedRankingService implements FeedRankingService {
     private static final int COMMENT_WEIGHT = 5;
 
     private final FeedRepository feedRepository;
+    private final FeedMonthlyRankingRepository feedMonthlyRankingRepository;
     private final ClubService clubService;
 
     @Override
@@ -73,12 +76,9 @@ private int getLastMonthRank(Long clubId, int year, int month) {
         int lastYear = month == 1 ? year - 1 : year;
         int lastMonth = month == 1 ? 12 : month - 1;
 
-        List<ClubFeedRankingQuery> lastMonthRankings = getClubFeedRanking(lastYear, lastMonth);
-        return lastMonthRankings.stream()
-                .filter(ranking -> ranking.clubId().equals(clubId))
-                .filter(ranking -> ranking.totalScore() > 0)
-                .findFirst()
-                .map(ClubFeedRankingQuery::rank)
+        return feedMonthlyRankingRepository
+                .findByClubIdAndTargetYearAndTargetMonth(clubId, lastYear, lastMonth)
+                .map(FeedMonthlyRanking::getRanking)
                 .orElse(0);
     }
 

src/test/java/ddingdong/ddingdongBE/domain/feed/service/GeneralFeedRankingServiceTest.java

@@ -5,12 +5,14 @@
 
 import ddingdong.ddingdongBE.common.fixture.ClubFixture;
 import ddingdong.ddingdongBE.common.fixture.FeedFixture;
+import ddingdong.ddingdongBE.common.fixture.FeedMonthlyRankingFixture;
 import ddingdong.ddingdongBE.common.fixture.UserFixture;
 import ddingdong.ddingdongBE.common.support.TestContainerSupport;
 import ddingdong.ddingdongBE.domain.club.entity.Club;
 import ddingdong.ddingdongBE.domain.club.repository.ClubRepository;
 import ddingdong.ddingdongBE.domain.feed.entity.Feed;
 import ddingdong.ddingdongBE.domain.feed.repository.FeedCommentRepository;
+import ddingdong.ddingdongBE.domain.feed.repository.FeedMonthlyRankingRepository;
 import ddingdong.ddingdongBE.domain.feed.repository.FeedRepository;
 import ddingdong.ddingdongBE.domain.feed.service.dto.query.ClubFeedRankingQuery;
 import ddingdong.ddingdongBE.domain.feed.service.dto.query.ClubMonthlyStatusQuery;
@@ -41,6 +43,9 @@ class GeneralFeedRankingServiceTest extends TestContainerSupport {
     @Autowired
     private FeedCommentRepository feedCommentRepository;
 
+    @Autowired
+    private FeedMonthlyRankingRepository feedMonthlyRankingRepository;
+
     @Autowired
     private UserRepository userRepository;
 
@@ -280,18 +285,17 @@ void getClubMonthlyStatus_rankAccuracy() {
         });
     }
 
-    @DisplayName("동아리 이달의 현황 조회 - 성공: 저번 달에 피드가 있으면 lastMonthRank가 반환된다")
+    @DisplayName("동아리 이달의 현황 조회 - 성공: 저번 달 스냅샷이 있으면 lastMonthRank가 반환된다")
     @Test
     void getClubMonthlyStatus_withLastMonthRank() {
         // given
         User user = userRepository.save(UserFixture.createClubUser());
         Club club = clubRepository.save(ClubFixture.createClub(user));
 
-        // 저번 달 피드 생성
+        // 저번 달 스냅샷 저장
         LocalDate lastMonth = LocalDate.now().minusMonths(1);
-        Feed lastMonthFeed = feedRepository.save(FeedFixture.createImageFeed(club, "저번달 피드"));
-        jdbcTemplate.update("UPDATE feed SET created_at = ? WHERE id = ?",
-                Timestamp.valueOf(lastMonth.atStartOfDay()), lastMonthFeed.getId());
+        feedMonthlyRankingRepository.save(FeedMonthlyRankingFixture.createWithRanking(
+                club.getId(), club.getName(), lastMonth.getYear(), lastMonth.getMonthValue(), 1));
 
         // 이번 달 피드 생성
         feedRepository.save(FeedFixture.createImageFeed(club, "이번달 피드"));
@@ -302,7 +306,7 @@ void getClubMonthlyStatus_withLastMonthRank() {
         // when
         ClubMonthlyStatusQuery result = feedRankingService.getClubMonthlyStatus(user.getId(), year, month);
 
-        // then — 저번 달에도 피드가 있으므로 lastMonthRank > 0
+        // then — 저번 달 스냅샷이 있으므로 lastMonthRank > 0
         assertSoftly(softly -> {
             softly.assertThat(result.rank()).isEqualTo(1);
             softly.assertThat(result.lastMonthRank()).isEqualTo(1);
@@ -336,11 +340,10 @@ void getClubMonthlyStatus_noCurrentMonthFeed_butHasLastMonthRank() {
         User user = userRepository.save(UserFixture.createClubUser());
         Club club = clubRepository.save(ClubFixture.createClub(user));
 
-        // 저번 달 피드만 생성 (이번 달 피드 없음)
+        // 저번 달 스냅샷만 저장 (이번 달 피드 없음)
         LocalDate lastMonth = LocalDate.now().minusMonths(1);
-        Feed lastMonthFeed = feedRepository.save(FeedFixture.createImageFeed(club, "저번달 피드"));
-        jdbcTemplate.update("UPDATE feed SET created_at = ? WHERE id = ?",
-                Timestamp.valueOf(lastMonth.atStartOfDay()), lastMonthFeed.getId());
+        feedMonthlyRankingRepository.save(FeedMonthlyRankingFixture.createWithRanking(
+                club.getId(), club.getName(), lastMonth.getYear(), lastMonth.getMonthValue(), 1));
 
         int year = LocalDate.now().getYear();
         int month = LocalDate.now().getMonthValue();
@@ -363,11 +366,11 @@ void getClubMonthlyStatus_januaryLooksAtDecember() {
         User user = userRepository.save(UserFixture.createClubUser());
         Club club = clubRepository.save(ClubFixture.createClub(user));
 
-        // 전년도 12월 피드 생성
         int currentYear = LocalDate.now().getYear();
-        Feed decemberFeed = feedRepository.save(FeedFixture.createImageFeed(club, "12월 피드"));
-        jdbcTemplate.update("UPDATE feed SET created_at = ? WHERE id = ?",
-                Timestamp.valueOf(LocalDateTime.of(currentYear - 1, 12, 15, 10, 0)), decemberFeed.getId());
+
+        // 전년도 12월 스냅샷 저장
+        feedMonthlyRankingRepository.save(FeedMonthlyRankingFixture.createWithRanking(
+                club.getId(), club.getName(), currentYear - 1, 12, 1));
 
         // 1월 피드 생성
         Feed januaryFeed = feedRepository.save(FeedFixture.createImageFeed(club, "1월 피드"));