feat(recommend): 홈 장르 추천 후보 조회를 보강한다

src/main/kotlin/kr/co/vividnext/sodalive/v2/recommend/adapter/out/persistence/DefaultHomeRecommendationQueryRepository.kt

@@ -826,51 +826,201 @@ class DefaultHomeRecommendationQueryRepository(
         genreLimit: Int,
         creatorLimit: Int
     ): List<HomeGenreCreatorRecommendationGroup> {
-        val genres = findGenreRecommendationTargets(
+        val groups = mutableListOf<HomeGenreCreatorRecommendationGroup>()
+        val selectedGenreIds = mutableSetOf<Long>()
+
+        val viewedTargets = findViewedGenreRecommendationTargets(
             memberId = memberId,
             includeAdultGenres = includeAdultGenres,
-            targetLimit = (genreLimit * creatorLimit).coerceAtLeast(genreLimit)
+            targetLimit = genreLimit
         )
 
-        return genres.asSequence().mapNotNull { genre ->
-            val creators = findCreatorsByGenre(
-                genreId = genre.id,
+        viewedTargets.forEach { target ->
+            groups.add(toGenreCreatorRecommendationGroup(target, memberId, includeAdultGenres, creatorLimit))
+            selectedGenreIds.add(target.id)
+        }
+
+        fillFallbackGenreCreatorGroups(
+            groups = groups,
+            selectedGenreIds = selectedGenreIds,
             memberId = memberId,
             includeAdultGenres = includeAdultGenres,
+            genreLimit = genreLimit,
             creatorLimit = creatorLimit
         )
-            creators.takeIf { it.isNotEmpty() }?.let {
-                HomeGenreCreatorRecommendationGroup(
-                    genreId = genre.id,
-                    genreName = genre.name,
-                    creators = it
-                )
-            }
-        }.toList()
+
+        return groups
     }
 
-    private fun findGenreRecommendationTargets(
+    private fun findViewedGenreRecommendationTargets(
         memberId: Long?,
         includeAdultGenres: Boolean,
         targetLimit: Int
     ): List<GenreRecommendationTarget> {
+        if (memberId == null || targetLimit <= 0) return emptyList()
+
+        val sql = """
+            select ct.id,
+                   ct.theme as genre
+            from content_theme ct
+            join (
+                select distinct c.theme_id
+                from creator_content_view_history ccvh
+                join content c on c.id = ccvh.content_id
+                where ccvh.member_id = :memberId
+            ) viewed on viewed.theme_id = ct.id
+            where ct.is_active = true
+              and ${eligibleGenreExistsSql()}
+            order by rand() asc
+            limit :targetLimit
+        """.trimIndent()
+
+        val query = entityManager.createNativeQuery(sql)
+            .setParameter("memberId", memberId)
+            .setParameter("includeAdultGenres", includeAdultGenres)
+            .setParameter("targetLimit", targetLimit)
+
+        @Suppress("UNCHECKED_CAST")
+        val rows = query.resultList as List<Array<Any?>>
+
+        return rows.map { row ->
+            GenreRecommendationTarget(
+                id = (row[0] as Number).toLong(),
+                name = row[1] as String,
+                isViewed = true
+            )
+        }
+    }
+
+    private fun fillFallbackGenreCreatorGroups(
+        groups: MutableList<HomeGenreCreatorRecommendationGroup>,
+        selectedGenreIds: MutableSet<Long>,
+        memberId: Long?,
+        includeAdultGenres: Boolean,
+        genreLimit: Int,
+        creatorLimit: Int
+    ) {
+        val fullTargets = findFallbackGenreRecommendationTargets(
+            memberId = memberId,
+            includeAdultGenres = includeAdultGenres,
+            excludedGenreIds = selectedGenreIds,
+            targetLimit = (genreLimit * creatorLimit).coerceAtLeast(genreLimit),
+            minCreatorCount = creatorLimit
+        )
+
+        fullTargets.forEach { target ->
+            groups.add(toGenreCreatorRecommendationGroup(target, memberId, includeAdultGenres, creatorLimit))
+            selectedGenreIds.add(target.id)
+        }
+        val partialTargets = findFallbackGenreRecommendationTargets(
+            memberId = memberId,
+            includeAdultGenres = includeAdultGenres,
+            excludedGenreIds = selectedGenreIds,
+            targetLimit = (genreLimit * creatorLimit).coerceAtLeast(genreLimit),
+            minCreatorCount = 1
+        )
+
+        partialTargets.forEach { target ->
+            groups.add(toGenreCreatorRecommendationGroup(target, memberId, includeAdultGenres, creatorLimit))
+            selectedGenreIds.add(target.id)
+        }
+    }
+
+    private fun findFallbackGenreRecommendationTargets(
+        memberId: Long?,
+        includeAdultGenres: Boolean,
+        excludedGenreIds: Set<Long>,
+        targetLimit: Int,
+        minCreatorCount: Int
+    ): List<GenreRecommendationTarget> {
+        if (targetLimit <= 0) return emptyList()
+
+        val excludedClause = if (excludedGenreIds.isEmpty()) "" else "and ct.id not in (:excludedGenreIds)"
         val sql = """
             select selected.id,
                    selected.genre
             from (
                 select ct.id,
                        ct.theme as genre,
-                       case when viewed.theme_id is null then 1 else 0 end as source_rank,
+                       count(distinct m.id) as creator_count,
                        rand() as random_tie_breaker
                 from content_theme ct
-                left join (
-                    select distinct c.theme_id
-                    from creator_content_view_history ccvh
-                    join content c on c.id = ccvh.content_id
-                    where (:memberId is not null and ccvh.member_id = :memberId)
-                ) viewed on viewed.theme_id = ct.id
+                join content c on c.theme_id = ct.id
+                join member m on m.id = c.member_id
                 where ct.is_active = true
-                  and exists (
+                  $excludedClause
+                  and c.is_active = true
+                  and (:includeAdultGenres = true or c.is_adult = false)
+                  and m.is_active = true
+                  and m.role = 'CREATOR'
+                  and not exists (
+                      select 1
+                      from creator_following cf
+                      where :memberId is not null
+                        and cf.member_id = :memberId
+                        and cf.creator_id = m.id
+                        and cf.is_active = true
+                  )
+                  and not exists (
+                      select 1
+                      from block_member bm
+                      where :memberId is not null
+                        and bm.is_active = true
+                        and (
+                            (bm.member_id = :memberId and bm.blocked_member_id = m.id)
+                            or (bm.member_id = m.id and bm.blocked_member_id = :memberId)
+                        )
+                  )
+                group by ct.id, ct.theme
+                having count(distinct m.id) >= :minCreatorCount
+            ) selected
+            order by selected.random_tie_breaker asc
+            limit :targetLimit
+        """.trimIndent()
+
+        val query = entityManager.createNativeQuery(sql)
+            .setParameter("memberId", memberId)
+            .setParameter("includeAdultGenres", includeAdultGenres)
+            .setParameter("targetLimit", targetLimit)
+            .setParameter("minCreatorCount", minCreatorCount)
+
+        if (excludedGenreIds.isNotEmpty()) {
+            query.setParameter("excludedGenreIds", excludedGenreIds)
+        }
+
+        @Suppress("UNCHECKED_CAST")
+        val rows = query.resultList as List<Array<Any?>>
+
+        return rows.map { row ->
+            GenreRecommendationTarget(
+                id = (row[0] as Number).toLong(),
+                name = row[1] as String
+            )
+        }
+    }
+
+    private fun toGenreCreatorRecommendationGroup(
+        target: GenreRecommendationTarget,
+        memberId: Long?,
+        includeAdultGenres: Boolean,
+        creatorLimit: Int
+    ): HomeGenreCreatorRecommendationGroup {
+        return HomeGenreCreatorRecommendationGroup(
+            genreId = target.id,
+            genreName = target.name,
+            isViewedTheme = target.isViewed,
+            creators = findCreatorsByGenre(
+                genreId = target.id,
+                memberId = memberId,
+                includeAdultGenres = includeAdultGenres,
+                creatorLimit = creatorLimit
+            )
+        )
+    }
+
+    private fun eligibleGenreExistsSql(): String {
+        return """
+            exists (
                 select 1
                 from content c
                 join member m on m.id = c.member_id
@@ -898,25 +1048,7 @@ class DefaultHomeRecommendationQueryRepository(
                         )
                   )
             )
-            ) selected
-            order by selected.source_rank asc, selected.random_tie_breaker asc
-            limit :targetLimit
         """.trimIndent()
-
-        val query = entityManager.createNativeQuery(sql)
-            .setParameter("memberId", memberId)
-            .setParameter("includeAdultGenres", includeAdultGenres)
-            .setParameter("targetLimit", targetLimit)
-
-        @Suppress("UNCHECKED_CAST")
-        val rows = query.resultList as List<Array<Any?>>
-
-        return rows.map { row ->
-            GenreRecommendationTarget(
-                id = (row[0] as Number).toLong(),
-                name = row[1] as String
-            )
-        }
     }
 
     private fun findCreatorsByGenre(
@@ -1130,6 +1262,7 @@ class DefaultHomeRecommendationQueryRepository(
 
     private data class GenreRecommendationTarget(
         val id: Long,
-        val name: String
+        val name: String,
+        val isViewed: Boolean = false
     )
 }

src/test/kotlin/kr/co/vividnext/sodalive/v2/recommend/adapter/out/persistence/DefaultHomeRecommendationQueryRepositoryTest.kt

@@ -1504,8 +1504,95 @@ class DefaultHomeRecommendationQueryRepositoryTest @Autowired constructor(
     }
 
     @Test
-    @DisplayName("장르 기반 크리에이터 추천은 서비스 중복 제거용 후보 그룹을 genreLimit보다 많이 반환한다")
-    fun shouldReturnMoreCandidateGroupsThanFinalGenreLimitForServiceDeduplicationBackfill() {
+    @DisplayName("조회 이력이 없으면 크리에이터 8명을 채울 수 있는 콘텐츠 테마 후보를 먼저 반환한다")
+    fun shouldRecommendFullRandomThemeCandidatesFirstWhenViewHistoryDoesNotExist() {
+        repeat(5) { themeIndex ->
+            val theme = saveTheme("no-history-underfilled-theme-$themeIndex")
+            saveAudioContent(
+                saveMember("no-history-underfilled-creator-$themeIndex", MemberRole.CREATOR),
+                LocalDateTime.of(2026, 5, 30, 10, 0).plusMinutes(themeIndex.toLong()),
+                isActive = true,
+                theme = theme
+            )
+        }
+        repeat(5) { themeIndex ->
+            val theme = saveTheme("no-history-full-theme-$themeIndex")
+            repeat(8) { creatorIndex ->
+                saveAudioContent(
+                    saveMember("no-history-full-$themeIndex-creator-$creatorIndex", MemberRole.CREATOR),
+                    LocalDateTime.of(2026, 5, 30, 11, 0).plusMinutes((themeIndex * 10 + creatorIndex).toLong()),
+                    isActive = true,
+                    theme = theme
+                )
+            }
+        }
+        flushAndClear()
+
+        val recommendations = repository.findGenreCreatorRecommendations(
+            memberId = null,
+            includeAdultGenres = false,
+            genreLimit = 5,
+            creatorLimit = 8
+        )
+
+        assertEquals(true, recommendations.size >= 5)
+        assertEquals(true, recommendations.take(5).all { it.genreName.startsWith("no-history-full-theme-") })
+        assertEquals(true, recommendations.take(5).all { it.creators.size == 8 })
+    }
+
+    @Test
+    @DisplayName("조회 이력 콘텐츠 테마는 8명이 되지 않아도 후보에 포함하고 부족한 장르는 8명 보유 테마 후보로 채운다")
+    fun shouldKeepViewedThemeCandidateEvenWhenUnderfilledAndReturnFullRandomThemeCandidates() {
+        val viewer = saveMember("viewed-partial-viewer", MemberRole.USER)
+        val viewedTheme = saveTheme("viewed-partial-theme")
+        val viewedContent = saveAudioContent(
+            saveMember("viewed-partial-creator", MemberRole.CREATOR),
+            LocalDateTime.of(2026, 5, 30, 10, 0),
+            isActive = true,
+            theme = viewedTheme
+        )
+        repeat(5) { themeIndex ->
+            val theme = saveTheme("viewed-fill-full-theme-$themeIndex")
+            repeat(8) { creatorIndex ->
+                saveAudioContent(
+                    saveMember("viewed-fill-full-$themeIndex-creator-$creatorIndex", MemberRole.CREATOR),
+                    LocalDateTime.of(2026, 5, 30, 11, 0).plusMinutes((themeIndex * 10 + creatorIndex).toLong()),
+                    isActive = true,
+                    theme = theme
+                )
+            }
+        }
+        entityManager.persist(
+            CreatorContentViewHistory(
+                memberId = viewer.id!!,
+                contentId = viewedContent.id!!,
+                genreId = 999L,
+                viewedAt = LocalDateTime.of(2026, 5, 31, 10, 0)
+            )
+        )
+        flushAndClear()
+
+        val recommendations = repository.findGenreCreatorRecommendations(
+            memberId = viewer.id!!,
+            includeAdultGenres = false,
+            genreLimit = 5,
+            creatorLimit = 8
+        )
+
+        assertEquals(true, recommendations.size >= 5)
+        assertEquals(true, recommendations.any { it.genreId == viewedTheme.id && it.creators.size == 1 })
+        assertEquals(
+            true,
+            recommendations
+                .filter { it.genreId != viewedTheme.id }
+                .take(4)
+                .all { it.genreName.startsWith("viewed-fill-full-theme-") && it.creators.size == 8 }
+        )
+    }
+
+    @Test
+    @DisplayName("장르 기반 크리에이터 추천 repository는 service 보충용 후보 그룹을 genreLimit보다 많이 반환한다")
+    fun shouldReturnMoreCandidateGroupsThanFinalGenreLimitForServiceBackfill() {
         val sharedCreator = saveMember("candidate-shared", MemberRole.CREATOR)
         val backfillCreator = saveMember("candidate-backfill", MemberRole.CREATOR)
         val firstTheme = saveTheme("candidate-first-theme")