From c9b6623eac6f5f01a1cf40648319062da6bbc3e4 Mon Sep 17 00:00:00 2001
From: klaus <klaus@vividnext.co.kr>
Date: Thu, 14 Aug 2025 18:13:40 +0900
Subject: [PATCH] =?UTF-8?q?perf(chat):=20DiffUtil=20=EB=B0=8F=20stableIds?=
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- ChatMessageAdapter에 DiffUtil 기반 submitList 도입으로 불필요한 전체 바인딩 제거
- RecyclerView 연결 시점에만 stableIds 활성화하여 테스트 환경 NPE 회피
- AI 프로필 이미지 중복 로딩 방지(tag 비교)로 네트워크/디코딩 비용 절감
- onViewRecycled에서 애니메이션/리스너/이미지 정리로 메모리 안정성 향상
---
 .../chat/talk/room/ChatMessageAdapter.kt      | 81 ++++++++++++++++++-
 1 file changed, 79 insertions(+), 2 deletions(-)

diff --git a/app/src/main/java/kr/co/vividnext/sodalive/chat/talk/room/ChatMessageAdapter.kt b/app/src/main/java/kr/co/vividnext/sodalive/chat/talk/room/ChatMessageAdapter.kt
index 7ee7b625..b6d934aa 100644
--- a/app/src/main/java/kr/co/vividnext/sodalive/chat/talk/room/ChatMessageAdapter.kt
+++ b/app/src/main/java/kr/co/vividnext/sodalive/chat/talk/room/ChatMessageAdapter.kt
@@ -17,6 +17,7 @@ import androidx.annotation.LayoutRes
 import androidx.annotation.VisibleForTesting
 import androidx.core.view.isVisible
 import androidx.recyclerview.widget.RecyclerView
+import androidx.recyclerview.widget.DiffUtil
 import kr.co.vividnext.sodalive.R
 import kr.co.vividnext.sodalive.databinding.ItemChatAiMessageBinding
 import kr.co.vividnext.sodalive.databinding.ItemChatTypingIndicatorBinding
@@ -81,6 +82,27 @@ class ChatMessageAdapter : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
 
     private val items: MutableList<ChatListItem> = mutableListOf()
 
+    private fun getStableIdFor(item: ChatListItem): Long {
+        return when (item) {
+            is ChatListItem.UserMessage -> {
+                val data = item.data
+                if (data.messageId != 0L) data.messageId
+                else (data.localId?.hashCode()?.toLong() ?: ("user:" + data.createdAt + data.message.hashCode()).hashCode().toLong())
+            }
+            is ChatListItem.AiMessage -> {
+                val data = item.data
+                if (data.messageId != 0L) data.messageId
+                else (data.localId?.hashCode()?.toLong() ?: ("ai:" + data.createdAt + data.message.hashCode()).hashCode().toLong())
+            }
+            is ChatListItem.Notice -> ("notice:" + item.text).hashCode().toLong()
+            is ChatListItem.TypingIndicator -> Long.MIN_VALUE // 고정 ID
+        }
+    }
+
+    override fun getItemId(position: Int): Long {
+        return getStableIdFor(items[position])
+    }
+
     // Notice 접기 상태 (간단 전역 토글)
     private var isNoticeCollapsed: Boolean = false
 
@@ -117,9 +139,33 @@ class ChatMessageAdapter : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
 
     @SuppressLint("NotifyDataSetChanged")
     fun setItems(newItems: List<ChatListItem>) {
+        // 하위 호환용: DiffUtil을 사용해 변경분만 반영
+        submitList(newItems)
+    }
+
+    /**
+     * DiffUtil을 사용해 최소 변경만 반영하는 submitList
+     */
+    fun submitList(newItems: List<ChatListItem>) {
+        val old = items.toList()
+        val diff = DiffUtil.calculateDiff(object : DiffUtil.Callback() {
+            override fun getOldListSize(): Int = old.size
+            override fun getNewListSize(): Int = newItems.size
+            override fun areItemsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
+                val o = old[oldItemPosition]
+                val n = newItems[newItemPosition]
+                // 안정 ID 기준 비교와 동일한 로직 적용
+                return getStableIdFor(o) == getStableIdFor(n)
+            }
+            override fun areContentsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
+                val o = old[oldItemPosition]
+                val n = newItems[newItemPosition]
+                return o == n
+            }
+        })
         items.clear()
         items.addAll(newItems)
-        notifyDataSetChanged()
+        diff.dispatchUpdatesTo(this)
     }
 
     /**
@@ -322,7 +368,12 @@ class ChatMessageAdapter : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
 
             // 프로필 이미지 로딩 (공용 유틸 + 둥근 모서리 적용)
             if (binding.ivProfile.isVisible) {
-                loadProfileImage(binding.ivProfile, data.profileImageUrl)
+                val oldUrl = binding.ivProfile.tag as? String
+                val newUrl = data.profileImageUrl
+                if (oldUrl != newUrl) {
+                    loadProfileImage(binding.ivProfile, newUrl)
+                    binding.ivProfile.tag = newUrl
+                }
             }
 
             // 그룹 내부 간격 최소화 (상단 패딩 축소)
@@ -420,6 +471,12 @@ class ChatMessageAdapter : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
     }
     // endregion
 
+    override fun onAttachedToRecyclerView(recyclerView: RecyclerView) {
+        super.onAttachedToRecyclerView(recyclerView)
+        // RecyclerView와 연결된 시점에 안정 ID 활성화 (JVM 테스트에서 NPE 회피)
+        setHasStableIds(true)
+    }
+
     override fun onViewAttachedToWindow(holder: RecyclerView.ViewHolder) {
         super.onViewAttachedToWindow(holder)
         if (holder is TypingIndicatorViewHolder) {
@@ -433,6 +490,26 @@ class ChatMessageAdapter : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
         }
         super.onViewDetachedFromWindow(holder)
     }
+
+    override fun onViewRecycled(holder: RecyclerView.ViewHolder) {
+        when (holder) {
+            is TypingIndicatorViewHolder -> holder.stopTypingAnimation()
+            is UserMessageViewHolder -> {
+                // 클릭 리스너 제거로 누수 및 중복 클릭 방지
+                holder.itemView.findViewById<View?>(R.id.iv_retry)?.setOnClickListener(null)
+            }
+            is AiMessageViewHolder -> {
+                // 이미지 태그/리소스 정리로 잘못된 재활용 방지
+                holder.itemView.findViewById<View?>(R.id.iv_profile)?.let { v ->
+                    (v as? android.widget.ImageView)?.apply {
+                        setImageDrawable(null)
+                        tag = null
+                    }
+                }
+            }
+        }
+        super.onViewRecycled(holder)
+    }
 }
 
 // endregion