HomeService fetchData 리팩토링 및 DB JOIN 기반 번역 적용

fetchData 함수에서 별도로 수행하던 번역 데이터 조회를 DB JOIN 및
COALESCE를 사용하도록 개선하여 성능을 최적화함.

- AudioContentRepository, RankingRepository 등에 locale 파라미터 추가
- DB 레벨에서 번역된 제목을 조회하도록 쿼리 수정
- HomeService에서 불필요한 getTranslatedContentList 호출 제거

src/main/kotlin/kr/co/vividnext/sodalive/api/home/HomeService.kt

@@ -14,7 +14,6 @@ import kr.co.vividnext.sodalive.content.series.ContentSeriesService
 import kr.co.vividnext.sodalive.content.series.GetSeriesListResponse
 import kr.co.vividnext.sodalive.content.series.translation.SeriesTranslationRepository
 import kr.co.vividnext.sodalive.content.theme.AudioContentThemeService
-import kr.co.vividnext.sodalive.content.translation.ContentTranslationRepository
 import kr.co.vividnext.sodalive.creator.admin.content.series.SeriesPublishedDaysOfWeek
 import kr.co.vividnext.sodalive.event.GetEventResponse
 import kr.co.vividnext.sodalive.explorer.ExplorerQueryRepository
@@ -50,7 +49,6 @@ class HomeService(
     private val rankingRepository: RankingRepository,
     private val explorerQueryRepository: ExplorerQueryRepository,
 
-    private val contentTranslationRepository: ContentTranslationRepository,
     private val aiCharacterTranslationRepository: AiCharacterTranslationRepository,
     private val seriesTranslationRepository: SeriesTranslationRepository,
 
@@ -122,8 +120,6 @@ class HomeService(
             isAdult = isAdult
         )
 
-        val translatedLatestContentList = getTranslatedContentList(contentList = latestContentList)
-
         val eventBannerList = GetEventResponse(
             totalCount = 0,
             eventList = emptyList()
@@ -177,64 +173,12 @@ class HomeService(
             sort = ContentRankingSortType.REVENUE
         )
 
-        val contentRankingContentIds = contentRanking.map { it.contentId }
-        val translatedContentRanking = if (contentRankingContentIds.isNotEmpty()) {
-            val translations = contentTranslationRepository
-                .findByContentIdInAndLocale(contentIds = contentRankingContentIds, locale = langContext.lang.code)
-                .associateBy { it.contentId }
-
-            contentRanking.map { item ->
-                val translatedTitle = translations[item.contentId]?.renderedPayload?.title
-                if (translatedTitle.isNullOrBlank()) {
-                    item
-                } else {
-                    item.copy(title = translatedTitle)
-                }
-            }
-        } else {
-            contentRanking
-        }
-
         val recommendChannelList = recommendChannelService.getRecommendChannel(
             memberId = memberId,
             isAdult = isAdult,
             contentType = contentType
         )
 
-        /**
-         * recommendChannelList의 콘텐츠 번역 데이터 조회
-         *
-         * languageCode != null
-         * contentTranslationRepository를 이용해 번역 콘텐츠를 조회한다. - contentId, locale
-         *
-         * 한 번에 조회하고 contentId를 매핑하여 recommendChannelList의 콘텐츠 title을 번역 데이터로 변경한다
-         */
-        val channelContentIds = recommendChannelList
-            .flatMap { it.contentList }
-            .map { it.contentId }
-            .distinct()
-
-        val translatedRecommendChannelList = if (channelContentIds.isNotEmpty()) {
-            val translations = contentTranslationRepository
-                .findByContentIdInAndLocale(contentIds = channelContentIds, locale = langContext.lang.code)
-                .associateBy { it.contentId }
-
-            recommendChannelList.map { channel ->
-                val translatedContentList = channel.contentList.map { item ->
-                    val translatedTitle = translations[item.contentId]?.renderedPayload?.title
-                    if (translatedTitle.isNullOrBlank()) {
-                        item
-                    } else {
-                        item.copy(title = translatedTitle)
-                    }
-                }
-
-                channel.copy(contentList = translatedContentList)
-            }
-        } else {
-            recommendChannelList
-        }
-
         val freeContentList = getRandomizedContentList(
             memberId = memberId,
             isAdult = isAdult,
@@ -248,8 +192,6 @@ class HomeService(
             isPointAvailableOnly = false
         )
 
-        val translatedFreeContentList = getTranslatedContentList(contentList = freeContentList)
-
         // 포인트 사용가능 콘텐츠 리스트 - 랜덤으로 가져오기 (DB에서 isPointAvailable 조건 적용)
         val pointAvailableContentList = getRandomizedContentList(
             memberId = memberId,
@@ -260,28 +202,26 @@ class HomeService(
             isPointAvailableOnly = true
         )
 
-        val translatedPointAvailableContentList = getTranslatedContentList(contentList = pointAvailableContentList)
-
         val excludeContentIds = (
-            translatedLatestContentList.map { it.contentId } +
-                translatedContentRanking.map { it.contentId }
+            latestContentList.map { it.contentId } +
+                contentRanking.map { it.contentId }
             ).distinct()
 
         return GetHomeResponse(
             liveList = liveList,
             creatorRanking = creatorRanking,
             latestContentThemeList = latestContentThemeList,
-            latestContentList = translatedLatestContentList,
+            latestContentList = latestContentList,
             bannerList = bannerList,
             eventBannerList = eventBannerList,
             originalAudioDramaList = translatedOriginalAudioDramaList,
             auditionList = auditionList,
             dayOfWeekSeriesList = translatedDayOfWeekSeriesList,
             popularCharacters = translatedPopularCharacters,
-            contentRanking = translatedContentRanking,
-            recommendChannelList = translatedRecommendChannelList,
-            freeContentList = translatedFreeContentList,
-            pointAvailableContentList = translatedPointAvailableContentList,
+            contentRanking = contentRanking,
+            recommendChannelList = recommendChannelList,
+            freeContentList = freeContentList,
+            pointAvailableContentList = pointAvailableContentList,
             recommendContentList = getRecommendContentList(
                 isAdultContentVisible = isAdultContentVisible,
                 contentType = contentType,
@@ -311,15 +251,13 @@ class HomeService(
             listOf(theme)
         }
 
-        val contentList = contentService.getLatestContentByTheme(
+        return contentService.getLatestContentByTheme(
             memberId = memberId,
             theme = themeList,
             contentType = contentType,
             isFree = false,
             isAdult = isAdult
         )
-
-        return getTranslatedContentList(contentList = contentList)
     }
 
     fun getDayOfWeekSeriesList(
@@ -445,7 +383,7 @@ class HomeService(
             }
         }
 
-        return getTranslatedContentList(contentList = result.take(RECOMMEND_TARGET_SIZE).shuffled())
+        return result.take(RECOMMEND_TARGET_SIZE).shuffled()
     }
 
     private fun pickByTimeDecay(
@@ -542,43 +480,7 @@ class HomeService(
             }
         }
 
-        return getTranslatedContentList(contentList = result.take(targetSize).shuffled())
-    }
-
-    /**
-     * 콘텐츠 리스트의 제목을 현재 언어(locale)에 맞춰 일괄 번역한다.
-     *
-     * 처리 절차:
-     * - 입력된 콘텐츠들의 contentId 집합을 만들고, 요청 언어 코드(langContext.lang.code)로
-     *   contentTranslationRepository에서 번역 데이터를 한 번에 조회한다.
-     * - 각 항목에 대해 번역된 제목이 존재하고 비어있지 않으면 title만 번역 값으로 교체한다.
-     * - 번역이 없거나 공백이면 원본 항목을 그대로 반환한다.
-     *
-     * 성능:
-     * - N건의 항목을 1회의 조회로 해결하기 위해 IN 쿼리를 사용한다.
-     *
-     * @param contentList 번역 대상 AudioContentMainItem 목록
-     * @return 제목이 가능한 항목은 번역된 목록(불변 사본), 그 외는 원본 항목 유지
-     */
-    private fun getTranslatedContentList(contentList: List<AudioContentMainItem>): List<AudioContentMainItem> {
-        val contentIds = contentList.map { it.contentId }
-
-        return if (contentIds.isNotEmpty()) {
-            val translations = contentTranslationRepository
-                .findByContentIdInAndLocale(contentIds = contentIds, locale = langContext.lang.code)
-                .associateBy { it.contentId }
-
-            contentList.map { item ->
-                val translatedTitle = translations[item.contentId]?.renderedPayload?.title
-                if (translatedTitle.isNullOrBlank()) {
-                    item
-                } else {
-                    item.copy(title = translatedTitle)
-                }
-            }
-        } else {
-            contentList
-        }
+        return result.take(targetSize).shuffled()
     }
 
     /**