fix(chat): 배경 선택 다이얼로그에서 초기 선택 복원이 되지 않는 문제 수정

- 선택 상태를 URL 비교에서 이미지 ID 우선 방식으로 변경
- URL만 저장된 기존 데이터에 대해 목록 로드 후 URL→ID 마이그레이션 추가
- SharedPreferences에 chat_bg_image_id_room_{roomId} 키 도입(호환 위해 URL 키 유지)

app/src/main/java/kr/co/vividnext/sodalive/chat/talk/TalkApi.kt

@@ -42,7 +42,8 @@ interface TalkApi {
     @GET("/api/chat/room/{roomId}/enter")
     fun enterChatRoom(
         @Header("Authorization") authHeader: String,
-        @Path("roomId") roomId: Long
+        @Path("roomId") roomId: Long,
+        @Query("characterImageId") characterImageId: Long?
     ): Single<ApiResponse<ChatRoomEnterResponse>>
 
     // 메시지 전송 API

app/src/main/java/kr/co/vividnext/sodalive/chat/talk/room/ChatBackgroundPickerDialogFragment.kt

@@ -42,12 +42,10 @@ class ChatBackgroundPickerDialogFragment : DialogFragment() {
     private var profileUrl: String = ""
 
     private val prefsName = "chat_room_prefs"
-    private fun bgUrlKey(roomId: Long) = "chat_bg_url_room_$roomId"
     private fun bgImageIdKey(roomId: Long) = "chat_bg_image_id_room_$roomId"
 
     private lateinit var adapter: BgAdapter
     private val items = mutableListOf<BgItem>()
-    private var selectedUrl: String? = null
     private var selectedId: Long? = null
 
     override fun onCreate(savedInstanceState: Bundle?) {
@@ -88,12 +86,10 @@ class ChatBackgroundPickerDialogFragment : DialogFragment() {
     }
 
     private fun loadData() {
-        // 초기 선택: 저장된 값 사용 (URL + ID 병행)
+        // 초기 선택: 저장된 이미지 ID 사용
         val prefs = requireActivity().getSharedPreferences(prefsName, Context.MODE_PRIVATE)
-        selectedUrl = prefs.getString(bgUrlKey(roomId), null)
         val savedId = prefs.getLong(bgImageIdKey(roomId), -1L)
         selectedId = if (savedId > 0) savedId else null
-
         items.clear()
 
         if (characterId > 0) {
@@ -105,38 +101,23 @@ class ChatBackgroundPickerDialogFragment : DialogFragment() {
                 .subscribe({ resp ->
                     val list = resp.data?.items.orEmpty()
                     items.addAll(list.map { BgItem(id = it.id, url = it.imageUrl) })
-                    adapter.submit(items, selectedId, selectedUrl)
+                    adapter.submit(items, selectedId)
 
-                    // 마이그레이션: 과거에 URL만 저장되어 있고 ID가 비어 있는 경우
-                    if (selectedId == null && !selectedUrl.isNullOrBlank()) {
-                        val found = items.firstOrNull { it.url == selectedUrl }
-                        if (found != null) {
-                            selectedId = found.id
-                            // UI 갱신
-                            adapter.updateSelected(found)
-                            // 영구 저장(ID 동기화)
-                            val p = requireActivity().getSharedPreferences(prefsName, Context.MODE_PRIVATE)
-                            p.edit {
-                                putLong(bgImageIdKey(roomId), found.id)
-                            }
-                        }
-                    }
 
                     loadingDialog.dismiss()
                 }, { _ ->
                     // 실패 시에도 현재까지의 목록 표시(없으면 빈 목록)
-                    adapter.submit(items, selectedId, selectedUrl)
+                    adapter.submit(items, selectedId)
                     loadingDialog.dismiss()
                 })
             compositeDisposable.add(d)
         } else {
             // characterId가 없으면 서버 요청 불가: 현재 저장된 선택 상태만 반영
-            adapter.submit(items, selectedId, selectedUrl)
+            adapter.submit(items, selectedId)
         }
     }
 
     private fun onSelect(item: BgItem) {
-        selectedUrl = item.url
         selectedId = item.id.takeIf { it > 0 }
         saveAndApply(item)
         adapter.updateSelected(item)
@@ -145,8 +126,10 @@ class ChatBackgroundPickerDialogFragment : DialogFragment() {
     private fun saveAndApply(item: BgItem) {
         val prefs = requireActivity().getSharedPreferences(prefsName, Context.MODE_PRIVATE)
         prefs.edit {
-            putString(bgUrlKey(roomId), item.url)
+            if (item.id > 0) putLong(
-            if (item.id > 0) putLong(bgImageIdKey(roomId), item.id) else remove(bgImageIdKey(roomId))
+                bgImageIdKey(roomId),
+                item.id
+            ) else remove(bgImageIdKey(roomId))
         }
         (activity as? ChatRoomActivity)?.setChatBackground(item.url)
     }
@@ -155,7 +138,8 @@ class ChatBackgroundPickerDialogFragment : DialogFragment() {
         super.onDestroyView()
         try {
             if (this::loadingDialog.isInitialized) loadingDialog.dismiss()
-        } catch (_: Throwable) { }
+        } catch (_: Throwable) {
+        }
         compositeDisposable.clear()
         _binding = null
     }
@@ -166,22 +150,19 @@ class ChatBackgroundPickerDialogFragment : DialogFragment() {
         private val onClick: (BgItem) -> Unit
     ) : RecyclerView.Adapter<BgVH>() {
         private val data = mutableListOf<BgItem>()
-        private var selectedUrl: String? = null
         private var selectedId: Long? = null
 
         @SuppressLint("NotifyDataSetChanged")
-        fun submit(items: List<BgItem>, selectedId: Long?, selectedUrl: String?) {
+        fun submit(items: List<BgItem>, selectedId: Long?) {
             data.clear()
             data.addAll(items)
             this.selectedId = selectedId
-            this.selectedUrl = selectedUrl
             notifyDataSetChanged()
         }
 
         @SuppressLint("NotifyDataSetChanged")
         fun updateSelected(item: BgItem) {
             this.selectedId = item.id.takeIf { it > 0 }
-            this.selectedUrl = item.url
             notifyDataSetChanged()
         }
 
@@ -195,7 +176,7 @@ class ChatBackgroundPickerDialogFragment : DialogFragment() {
         override fun getItemCount(): Int = data.size
 
         override fun onBindViewHolder(holder: BgVH, position: Int) {
-            holder.bind(data[position], selectedId, selectedUrl)
+            holder.bind(data[position], selectedId)
         }
     }
 
@@ -203,13 +184,15 @@ class ChatBackgroundPickerDialogFragment : DialogFragment() {
         private val binding: ItemChatBackgroundImageBinding,
         private val onClick: (BgItem) -> Unit
     ) : RecyclerView.ViewHolder(binding.root) {
-        fun bind(item: BgItem, selectedId: Long?, selectedUrl: String?) {
+        fun bind(item: BgItem, selectedId: Long?) {
             binding.ivImage.load(item.url) {
                 placeholder(R.drawable.ic_placeholder_profile)
                 error(R.drawable.ic_placeholder_profile)
             }
-            val selected = (selectedId != null && item.id == selectedId) ||
+            val selected = when {
-                (selectedUrl != null && selectedUrl == item.url)
+                selectedId != null -> item.id == selectedId
+                else -> item.id == 0L // 저장된 ID가 없으면 프로필(id=0)을 선택으로 간주
+            }
             binding.tvCurrent.visibility = if (selected) View.VISIBLE else View.GONE
             binding.viewBorder.visibility = if (selected) View.VISIBLE else View.GONE
             binding.root.setOnClickListener { onClick(item) }

app/src/main/java/kr/co/vividnext/sodalive/chat/talk/room/ChatRepository.kt

@@ -86,8 +86,8 @@ class ChatRepository(
      * 통합 채팅방 입장: 서버 캐릭터 정보 + 최신 메시지 수신 후 로컬 DB 업데이트
      * - 로컬 데이터가 없더라도 서버 응답을 기준으로 동기화
      */
-    fun enterChatRoom(token: String, roomId: Long): Single<ChatRoomEnterResponse> {
+    fun enterChatRoom(token: String, roomId: Long, characterImageId: Long?): Single<ChatRoomEnterResponse> {
-        return talkApi.enterChatRoom(authHeader = token, roomId = roomId)
+        return talkApi.enterChatRoom(authHeader = token, roomId = roomId, characterImageId = characterImageId)
             .subscribeOn(Schedulers.io())
             .flatMap { response ->
                 val data = ensureSuccess(response)

app/src/main/java/kr/co/vividnext/sodalive/chat/talk/room/ChatRoomActivity.kt

@@ -96,8 +96,7 @@ class ChatRoomActivity : BaseActivity<ActivityChatRoomBinding>(
             binding.tvName.text = ""
             binding.ivProfile.setImageResource(R.drawable.ic_placeholder_profile)
             binding.ivBackgroundProfile.setImageResource(R.drawable.ic_placeholder_profile)
-            // 저장된 배경이 있으면 즉시 적용 (네트워크 응답 전 초기 진입에서도 반영)
+            // 배경은 서버 응답 수신 시 적용 (기본은 플레이스홀더 유지)
-            applyBackgroundFromPrefsOrProfile("")
             // 배지는 기본 Clone으로 둔다가 실제 값으로 갱신 (디자인 기본 배경도 clone)
             binding.tvCharacterTypeBadge.text = "Clone"
             binding.tvCharacterTypeBadge.setBackgroundResource(R.drawable.bg_character_status_clone)
@@ -121,8 +120,7 @@ class ChatRoomActivity : BaseActivity<ActivityChatRoomBinding>(
 
         // 프로필 이미지 (공용 유틸 + 둥근 모서리 적용)
         loadProfileImage(binding.ivProfile, info.profileImageUrl)
-        // 배경 이미지: 저장된 값 우선, 없으면 프로필로 저장/적용
+        // 배경 이미지는 서버 응답의 backgroundImageUrl을 우선 적용 (enter 완료 시 처리)
-        applyBackgroundFromPrefsOrProfile(info.profileImageUrl)
 
         // 타입 배지 텍스트 및 배경
         val (badgeText, badgeBg) = when (info.characterType) {
@@ -607,12 +605,21 @@ class ChatRoomActivity : BaseActivity<ActivityChatRoomBinding>(
 
         // 2) 서버 통합 API로 동기화 및 UI 갱신
         val token = "Bearer ${SharedPreferenceManager.token}"
-        val networkDisposable = chatRepository.enterChatRoom(token = token, roomId = roomId)
+        val bgImageId = getSavedBackgroundImageId()
+        val networkDisposable = chatRepository.enterChatRoom(token = token, roomId = roomId, characterImageId = bgImageId)
             .observeOn(AndroidSchedulers.mainThread())
             .subscribe({ response ->
                 // 캐릭터 정보 바인딩
                 setCharacterInfo(response.character)
 
+                // 배경 이미지 적용: 서버 응답의 backgroundImageUrl 우선, 없으면 프로필 사용
+                val bgUrl = response.backgroundImageUrl ?: response.character.profileImageUrl
+                if (bgUrl.isNotBlank()) {
+                    setChatBackground(bgUrl)
+                } else {
+                    binding.ivBackgroundProfile.setImageResource(R.drawable.ic_placeholder_profile)
+                }
+
                 // 메시지 정렬(오래된 -> 최신) + 동시간대는 messageId 오름차순으로 안정화
                 val sorted =
                     response.messages.sortedWith(compareBy<ServerChatMessage> { it.createdAt }.thenBy { it.messageId })
@@ -870,6 +877,13 @@ class ChatRoomActivity : BaseActivity<ActivityChatRoomBinding>(
 
     fun getCharacterProfileUrl(): String = characterInfo?.profileImageUrl ?: ""
 
+    private fun bgImageIdPrefKey(): String = "chat_bg_image_id_room_$roomId"
+
+    private fun getSavedBackgroundImageId(): Long? {
+        val id = prefs.getLong(bgImageIdPrefKey(), -1L)
+        return if (id > 0) id else null
+    }
+
     fun onResetChatRequested() {
         val title = "대화 초기화"
         val desc = "지금까지의 대화가 모두 초기화 되고 새롭게 대화를 시작합니다."

app/src/main/java/kr/co/vividnext/sodalive/chat/talk/room/ChatRoomEnterResponse.kt

@@ -13,5 +13,6 @@ data class ChatRoomEnterResponse(
     @SerializedName("messages") val messages: List<ServerChatMessage>,
     @SerializedName("hasMoreMessages") val hasMoreMessages: Boolean,
     @SerializedName("totalRemaining") val totalRemaining: Int = 0,
-    @SerializedName("nextRechargeAtEpoch") val nextRechargeAtEpoch: Long? = null
+    @SerializedName("nextRechargeAtEpoch") val nextRechargeAtEpoch: Long? = null,
+    @SerializedName("bgImageUrl") val backgroundImageUrl: String? = null
 )

app/src/test/java/kr/co/vividnext/sodalive/chat/talk/room/ChatRepositoryTest.kt

@@ -27,10 +27,10 @@ class ChatRepositoryTest {
         val character = CharacterInfo(10, "name", "", CharacterType.CLONE)
         val resp = ChatRoomEnterResponse(99, character, serverMessages, hasMoreMessages = false)
 
-        every { api.enterChatRoom(any(), any()) } returns Single.just(ApiResponse(true, resp, null))
+        every { api.enterChatRoom(any(), any(), any()) } returns Single.just(ApiResponse(true, resp, null))
         coEvery { dao.getNthLatestCreatedAt(any(), any()) } returns null
 
-        val result = repo.enterChatRoom("token", 99).blockingGet()
+        val result = repo.enterChatRoom("token", 99, null).blockingGet()
 
         // 반환 검증
         assertEquals(99, result.roomId)