feat(interaction): 新增分集计数统计接口

fruitshorts-module-playback/src/main/java/com/fruitshorts/playback/service/FavoriteService.java

@@ -17,9 +17,12 @@ import org.springframework.transaction.annotation.Transactional;
 
 import java.time.LocalDateTime;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 /** 收藏：切换、列表、批量删除；收藏数在同一事务内同步维护。 */
 @Service
@@ -63,6 +66,28 @@ public class FavoriteService {
         return count != null && count > 0;
     }
 
+    /** 批量判断用户是否已收藏，一次查询覆盖多部剧。 */
+    public Set<Long> favoriteDramaIds(Long userId, Collection<Long> dramaIds) {
+        if (userId == null || dramaIds == null || dramaIds.isEmpty()) {
+            return Set.of();
+        }
+        Set<Long> normalized = new HashSet<>();
+        for (Long dramaId : dramaIds) {
+            if (dramaId != null) {
+                normalized.add(dramaId);
+            }
+        }
+        if (normalized.isEmpty()) {
+            return Set.of();
+        }
+        return favoriteMapper.selectList(Wrappers.<UserFavorite>lambdaQuery()
+                        .eq(UserFavorite::getUserId, userId)
+                        .in(UserFavorite::getDramaId, normalized))
+                .stream()
+                .map(UserFavorite::getDramaId)
+                .collect(java.util.stream.Collectors.toSet());
+    }
+
     /** 分页查询收藏短剧，保持收藏时间与 dramaId 稳定排序。 */
     public PageResult<Drama> page(Long userId, int pageIndex, int pageSize) {
         int safeIndex = Math.max(pageIndex, 1);