feat: 몰입형 투표 랜덤 다음 조회 API 추가

src/main/java/com/ject/vs/vote/adapter/web/ImmersiveVoteController.java

@@ -3,6 +3,8 @@
 import com.ject.vs.config.AnonymousId;
 import com.ject.vs.vote.adapter.web.dto.ImmersiveFeedResponse;
 import com.ject.vs.vote.adapter.web.dto.ImmersiveLiveResponse;
+import com.ject.vs.vote.adapter.web.dto.ImmersiveNextRequest;
+import com.ject.vs.vote.adapter.web.dto.ImmersiveNextResponse;
 import com.ject.vs.vote.adapter.web.dto.ImmersiveParticipateResponse;
 import com.ject.vs.vote.adapter.web.dto.ParticipateRequest;
 import com.ject.vs.vote.adapter.web.dto.ShareLinkResponse;
@@ -63,4 +65,15 @@ public ImmersiveLiveResponse getLive(@PathVariable Long voteId) {
     public ShareLinkResponse getShareLink(@PathVariable Long voteId) {
         return ShareLinkResponse.from(voteResultQueryUseCase.getShareLink(voteId));
     }
+
+    @Operation(summary = "랜덤 다음 투표 조회", description = "excludeIds를 제외한 진행 중인 투표를 랜덤으로 조회합니다. 모든 투표 소진 시 빈 배열 반환 → 클라이언트에서 excludeIds 초기화 후 재요청 (무한 순환)")
+    @PostMapping("/next")
+    public ImmersiveNextResponse getNextRandom(
+            @RequestBody @Valid ImmersiveNextRequest request,
+            @AuthenticationPrincipal Long userId,
+            @Parameter(hidden = true) @AnonymousId String anonymousId) {
+        return ImmersiveNextResponse.from(
+                immersiveVoteQueryUseCase.getNextRandom(request.excludeIds(), request.size(), userId, anonymousId)
+        );
+    }
 }

src/main/java/com/ject/vs/vote/adapter/web/dto/ImmersiveNextRequest.java

@@ -0,0 +1,20 @@
+package com.ject.vs.vote.adapter.web.dto;
+
+import jakarta.validation.constraints.Max;
+import jakarta.validation.constraints.Min;
+
+import java.util.List;
+
+public record ImmersiveNextRequest(
+        List<Long> excludeIds,
+
+        @Min(1)
+        @Max(50)
+        Integer size
+) {
+    public ImmersiveNextRequest {
+        if (size == null) {
+            size = 10;
+        }
+    }
+}

src/main/java/com/ject/vs/vote/adapter/web/dto/ImmersiveNextResponse.java

@@ -0,0 +1,78 @@
+package com.ject.vs.vote.adapter.web.dto;
+
+import com.ject.vs.vote.domain.VoteEmoji;
+import com.ject.vs.vote.port.in.ImmersiveVoteQueryUseCase.ImmersiveNextResult;
+
+import java.time.Instant;
+import java.time.OffsetDateTime;
+import java.time.ZoneOffset;
+import java.util.List;
+import java.util.Map;
+
+public record ImmersiveNextResponse(List<VoteItem> items) {
+
+    public record VoteItem(
+            Long voteId,
+            String title,
+            String content,
+            String imageUrl,
+            OffsetDateTime endAt,
+            List<OptionItem> options,
+            MyVote myVote,
+            EmojiSummary emojiSummary,
+            String myEmoji,
+            int commentCount,
+            int currentViewerCount
+    ) {
+    }
+
+    public record OptionItem(Long optionId, String label, Long voteCount, Integer ratio) {
+    }
+
+    public record MyVote(boolean voted, Long selectedOptionId) {
+    }
+
+    public record EmojiSummary(long LIKE, long SAD, long ANGRY, long WOW, long total) {
+        public static EmojiSummary from(Map<VoteEmoji, Long> map, long total) {
+            return new EmojiSummary(
+                    map.getOrDefault(VoteEmoji.LIKE, 0L),
+                    map.getOrDefault(VoteEmoji.SAD, 0L),
+                    map.getOrDefault(VoteEmoji.ANGRY, 0L),
+                    map.getOrDefault(VoteEmoji.WOW, 0L),
+                    total
+            );
+        }
+    }
+
+    private static OffsetDateTime toKst(Instant instant) {
+        return instant.atOffset(ZoneOffset.ofHours(9));
+    }
+
+    public static ImmersiveNextResponse from(ImmersiveNextResult result) {
+        List<VoteItem> items = result.items().stream()
+                .map(i -> {
+                    List<OptionItem> options = i.options().stream()
+                            .map(o -> new OptionItem(o.optionId(), o.label(), o.voteCount(), o.ratio()))
+                            .toList();
+                    MyVote myVote = new MyVote(i.voted(), i.mySelectedOptionId());
+                    EmojiSummary emojiSummary = EmojiSummary.from(i.emojiSummary(), i.emojiTotal());
+                    String myEmoji = i.myEmoji() != null ? i.myEmoji().name() : null;
+
+                    return new VoteItem(
+                            i.voteId(),
+                            i.title(),
+                            i.content(),
+                            i.imageUrl(),
+                            toKst(i.endAt()),
+                            options,
+                            myVote,
+                            emojiSummary,
+                            myEmoji,
+                            i.commentCount(),
+                            i.currentViewerCount()
+                    );
+                })
+                .toList();
+        return new ImmersiveNextResponse(items);
+    }
+}

src/main/java/com/ject/vs/vote/domain/VoteRepository.java

@@ -149,7 +149,7 @@ Slice<Vote> findFirstPageForHomeByEndingSoon(
     @Query("""
         SELECT v FROM Vote v
         WHERE v.endAt > :now
-          AND (v.endAt > :lastEndAt 
+          AND (v.endAt > :lastEndAt
                OR (v.endAt = :lastEndAt AND v.id > :lastId))
         ORDER BY v.endAt ASC, v.id ASC
         """)
@@ -159,4 +159,40 @@ Slice<Vote> findForHomeByEndingSoonWithKeyset(
             @Param("now") Instant now,
             Pageable pageable
     );
+
+    // ===== 몰입형 투표 랜덤 조회 =====
+
+    /**
+     * 진행 중인 투표 중 excludeIds를 제외하고 랜덤으로 조회
+     */
+    @Query("""
+        SELECT v FROM Vote v
+        WHERE v.endAt > :now
+          AND v.id NOT IN :excludeIds
+        ORDER BY FUNCTION('RANDOM')
+        """)
+    Slice<Vote> findRandomExcluding(
+            @Param("now") Instant now,
+            @Param("excludeIds") List<Long> excludeIds,
+            Pageable pageable
+    );
+
+    /**
+     * 진행 중인 투표 랜덤 조회 (excludeIds 없는 첫 조회용)
+     */
+    @Query("""
+        SELECT v FROM Vote v
+        WHERE v.endAt > :now
+        ORDER BY FUNCTION('RANDOM')
+        """)
+    Slice<Vote> findRandom(
+            @Param("now") Instant now,
+            Pageable pageable
+    );
+
+    /**
+     * 진행 중인 투표 총 개수 조회 (무한 순환 판단용)
+     */
+    @Query("SELECT COUNT(v) FROM Vote v WHERE v.endAt > :now")
+    long countOngoing(@Param("now") Instant now);
 }

src/main/java/com/ject/vs/vote/port/ImmersiveVoteQueryService.java

@@ -89,6 +89,25 @@ public ImmersiveLiveResult getLive(Long voteId) {
         return new ImmersiveLiveResult(liveOptions, 0, (int) total);
     }
 
+    @Override
+    public ImmersiveNextResult getNextRandom(List<Long> excludeIds, int size, Long userId, String anonymousId) {
+        Instant now = Instant.now(clock);
+        PageRequest pageable = PageRequest.of(0, size);
+
+        Slice<Vote> slice;
+        if (excludeIds == null || excludeIds.isEmpty()) {
+            slice = voteRepository.findRandom(now, pageable);
+        } else {
+            slice = voteRepository.findRandomExcluding(now, excludeIds, pageable);
+        }
+
+        List<ImmersiveFeedItem> items = slice.getContent().stream()
+                .map(v -> toFeedItem(v, userId, anonymousId))
+                .toList();
+
+        return new ImmersiveNextResult(items);
+    }
+
     private ImmersiveFeedItem toFeedItem(Vote vote, Long userId, String anonymousId) {
         Long voteId = vote.getId();
         long total = voteParticipationRepository.countByVoteId(voteId);
@@ -140,11 +159,14 @@ private ImmersiveFeedItem toFeedItem(Vote vote, Long userId, String anonymousId)
 
         int commentCount = (int) chatMessageRepository.countByVoteId(voteId);
 
+        // imageFile 없이 생성된 투표는 imageUrl이 null이므로 thumbnailUrl로 폴백한다.
+        String imageUrl = vote.getImageUrl() != null ? vote.getImageUrl() : vote.getThumbnailUrl();
+
         return new ImmersiveFeedItem(
                 voteId,
                 vote.getTitle(),
                 vote.getContent(),
-                vote.getImageUrl(),
+                imageUrl,
                 vote.getEndAt(),
                 options,
                 voted,

src/main/java/com/ject/vs/vote/port/in/ImmersiveVoteQueryUseCase.java

@@ -12,6 +12,11 @@ public interface ImmersiveVoteQueryUseCase {
 
     ImmersiveLiveResult getLive(Long voteId);
 
+    /**
+     * 랜덤 다음 투표 조회 (excludeIds 제외, 무한 순환)
+     */
+    ImmersiveNextResult getNextRandom(List<Long> excludeIds, int size, Long userId, String anonymousId);
+
     record ImmersiveFeedResult(List<ImmersiveFeedItem> items, Long nextCursor, boolean hasNext) {
     }
 
@@ -44,4 +49,10 @@ record ImmersiveLiveResult(
 
     record LiveOptionItem(Long optionId, long voteCount, int ratio) {
     }
+
+    /**
+     * 랜덤 다음 투표 조회 결과 (무한 순환용)
+     */
+    record ImmersiveNextResult(List<ImmersiveFeedItem> items) {
+    }
 }

src/unitTest/java/com/ject/vs/vote/port/ImmersiveVoteQueryServiceTest.java

@@ -141,6 +141,34 @@ void setUp() {
             assertThat(result.items().get(0).mySelectedOptionId()).isEqualTo(77L);
         }
 
+        @Test
+        void imageUrl_있으면_그대로_노출() {
+            Vote vote = makeVote(Duration.ofHours(24));   // thumbnailUrl="t", imageUrl="img.png"
+            given(voteRepository.findByEndAtAfterOrderByIdDesc(any(), any()))
+                    .willReturn(new SliceImpl<>(List.of(vote), PageRequest.of(0, 10), false));
+            given(voteOptionRepository.findByVoteIdOrderByPosition(any())).willReturn(List.of());
+            given(emojiReactionRepository.countByEmojiForVote(any())).willReturn(List.of());
+            given(voteParticipationRepository.countByVoteId(any())).willReturn(0L);
+
+            ImmersiveFeedResult result = service.getFeed(null, null, 10, null, null);
+
+            assertThat(result.items().get(0).imageUrl()).isEqualTo("img.png");
+        }
+
+        @Test
+        void imageUrl_null이면_thumbnailUrl로_폴백() {
+            Vote vote = Vote.create("몰입", null, "thumb.png", null, Duration.ofHours(24), FIXED_CLOCK);
+            given(voteRepository.findByEndAtAfterOrderByIdDesc(any(), any()))
+                    .willReturn(new SliceImpl<>(List.of(vote), PageRequest.of(0, 10), false));
+            given(voteOptionRepository.findByVoteIdOrderByPosition(any())).willReturn(List.of());
+            given(emojiReactionRepository.countByEmojiForVote(any())).willReturn(List.of());
+            given(voteParticipationRepository.countByVoteId(any())).willReturn(0L);
+
+            ImmersiveFeedResult result = service.getFeed(null, null, 10, null, null);
+
+            assertThat(result.items().get(0).imageUrl()).isEqualTo("thumb.png");
+        }
+
         @Test
         void 미참여시_mySelectedOptionId_null() {
             Vote vote = makeVote(Duration.ofHours(24));