src/main/kotlin/kr/co/vividnext/sodalive/fcm/PushTokenRepository.kt

@@ -9,6 +9,7 @@ interface PushTokenRepository : JpaRepository<PushToken, Long>, PushTokenQueryRe
 interface PushTokenQueryRepository {
     fun findByToken(token: String): PushToken?
     fun findByMemberId(memberId: Long): List<PushToken>
+    fun findByMemberIds(memberIds: List<Long>): List<PushToken>
 }
 
 class PushTokenQueryRepositoryImpl(
@@ -27,4 +28,12 @@ class PushTokenQueryRepositoryImpl(
             .where(pushToken.member.id.eq(memberId))
             .fetch()
     }
+
+    override fun findByMemberIds(memberIds: List<Long>): List<PushToken> {
+        if (memberIds.isEmpty()) return emptyList()
+        return queryFactory
+            .selectFrom(pushToken)
+            .where(pushToken.member.id.`in`(memberIds))
+            .fetch()
+    }
 }

src/main/kotlin/kr/co/vividnext/sodalive/live/room/LiveRoomService.kt

@@ -21,6 +21,7 @@ import kr.co.vividnext.sodalive.explorer.ExplorerQueryRepository
 import kr.co.vividnext.sodalive.extensions.convertLocalDateTime
 import kr.co.vividnext.sodalive.fcm.FcmEvent
 import kr.co.vividnext.sodalive.fcm.FcmEventType
+import kr.co.vividnext.sodalive.fcm.PushTokenRepository
 import kr.co.vividnext.sodalive.i18n.LangContext
 import kr.co.vividnext.sodalive.i18n.SodaMessageSource
 import kr.co.vividnext.sodalive.live.reservation.LiveReservationRepository
@@ -95,6 +96,7 @@ class LiveRoomService(
     private val roomVisitService: LiveRoomVisitService,
     private val canPaymentService: CanPaymentService,
     private val chargeRepository: ChargeRepository,
+    private val pushTokenRepository: PushTokenRepository,
     private val memberRepository: MemberRepository,
     private val tagRepository: LiveTagRepository,
     private val canRepository: CanRepository,
@@ -126,6 +128,62 @@ class LiveRoomService(
         }
     }
 
+    private fun applyLanguageTagToRoomTags(
+        memberId: Long?,
+        tags: List<String>,
+        languageTagByMemberId: Map<Long, String?>? = null
+    ): List<String> {
+        val randomizedTags = tags.shuffled()
+        val languageTag = getCreatorLanguageTag(memberId, languageTagByMemberId) ?: return randomizedTags
+        val filteredTags = randomizedTags.filterNot { it == languageTag }
+        return listOf(languageTag) + filteredTags
+    }
+
+    private fun getCreatorLanguageTag(
+        memberId: Long?,
+        languageTagByMemberId: Map<Long, String?>? = null
+    ): String? {
+        if (memberId == null) return null
+        if (languageTagByMemberId != null && languageTagByMemberId.containsKey(memberId)) {
+            return languageTagByMemberId[memberId]
+        }
+
+        val tokens = pushTokenRepository.findByMemberId(memberId)
+        val languageCode = tokens
+            .filterNot { it.languageCode.isNullOrBlank() }
+            .maxByOrNull { it.updatedAt ?: LocalDateTime.MIN }
+            ?.languageCode
+
+        val languageTag = when (languageCode?.lowercase()?.take(2)) {
+            "ko" -> "한국어"
+            "ja" -> "일본어"
+            "en" -> "영어"
+            else -> null
+        }
+        return languageTag
+    }
+
+    private fun buildLanguageTagMap(memberIds: List<Long>): Map<Long, String?> {
+        val tokens = pushTokenRepository.findByMemberIds(memberIds)
+        if (tokens.isEmpty()) return emptyMap()
+
+        val latestTokenByMemberId = tokens
+            .filter { it.member?.id != null }
+            .groupBy { it.member!!.id!! }
+            .mapValues { (_, memberTokens) ->
+                memberTokens.maxByOrNull { it.updatedAt ?: LocalDateTime.MIN }
+            }
+
+        return latestTokenByMemberId.mapValues { (_, token) ->
+            when (token?.languageCode?.lowercase()?.take(2)) {
+                "ko" -> "한국어"
+                "ja" -> "일본어"
+                "en" -> "영어"
+                else -> null
+            }
+        }
+    }
+
     @Transactional(readOnly = true)
     fun getRoomList(
         dateString: String?,
@@ -161,6 +219,9 @@ class LiveRoomService(
             )
         }
 
+        val creatorIds = roomList.mapNotNull { it.member?.id }.distinct()
+        val languageTagByMemberId = buildLanguageTagMap(creatorIds)
+
         return roomList
             .filter {
                 if (member?.id != null) {
@@ -193,6 +254,11 @@ class LiveRoomService(
                 val beginDateTimeUtc = it.beginDateTime
                     .format(DateTimeFormatter.ISO_LOCAL_DATE_TIME)
 
+                val tags = it.tags
+                    .filter { tag -> tag.tag.isActive }
+                    .map { tag -> tag.tag.tag }
+                    .let { list -> applyLanguageTagToRoomTags(it.member?.id, list, languageTagByMemberId) }
+
                 GetRoomListResponse(
                     roomId = it.id!!,
                     title = it.title,
@@ -213,11 +279,7 @@ class LiveRoomService(
                     },
                     creatorNickname = it.member!!.nickname,
                     creatorId = it.member!!.id!!,
-                    tags = it.tags
+                    tags = tags,
-                        .asSequence()
-                        .filter { tag -> tag.tag.isActive }
-                        .map { tag -> tag.tag.tag }
-                        .toList(),
                     coverImageUrl = if (it.coverImage!!.startsWith("https://")) {
                         it.coverImage!!
                     } else {
@@ -440,12 +502,17 @@ class LiveRoomService(
         val beginDateTimeUtc = room.beginDateTime
             .format(DateTimeFormatter.ISO_LOCAL_DATE_TIME)
 
+        val languageTagByMemberId = buildLanguageTagMap(listOfNotNull(room.member?.id))
         val response = GetRoomDetailResponse(
             roomId = roomId,
             title = room.title,
             notice = room.notice,
             price = room.price,
-            tags = room.tags.asSequence().filter { it.tag.isActive }.map { it.tag.tag }.toList(),
+            tags = room.tags.asSequence()
+                .filter { it.tag.isActive }
+                .map { it.tag.tag }
+                .toList()
+                .let { tags -> applyLanguageTagToRoomTags(room.member?.id, tags, languageTagByMemberId) },
             numberOfParticipantsTotal = room.numberOfPeople,
             numberOfParticipants = 0,
             channelName = room.channelName,