chore：进入客服页面不乱跳了

components/ai-chat-message/ai-chat-message.vue

@@ -5,8 +5,8 @@
       class="chat-messages" 
       scroll-y 
       :scroll-top="scrollTop"
-      @scrolltoupper="loadMoreHistory"
+       @scroll="onScroll"
-      :scroll-with-animation="true">
+      :scroll-with-animation="false">
       
       <!-- 加载更多历史消息 -->
       <view class="load-more" v-if="hasMoreHistory">
@@ -16,7 +16,7 @@
       <!-- 消息列表 -->
       <view 
         v-for="(message, index) in messages" 
-        :key="message.id + '-' + index"  
+        :key="`msg-${message.id || message.timestamp}-${index}`"  
         class="message-item"
         :class="[message.role, { 'first-message': index === 0 }]">
         
@@ -402,7 +402,7 @@ export default {
       default: 20
     }
   },
-  data() {
+  data(){
     return {
       messages: [],
       inputText: '',
@@ -437,7 +437,11 @@ export default {
       isAIServiceAvailable: true,
       aiServiceError: null,
 	  isLoadingHistory: false, // 新增：标记历史加载状态
-      shouldScrollToBottom: false
+      shouldScrollToBottom: false,
+	   scrollTimer: null,
+	  lastScrollTop: 0,
+	  historyOffset: 0,
+	   isFetchingHistory: false
     }
   },
   onShow() {
@@ -449,10 +453,17 @@ export default {
            } else {
              this.currentConversationId = aiService.getConversationId();
            }
-           this.loadChatHistoryIfExist();
+           // 加载初始历史后，同步historyOffset
-
+               this.loadChatHistoryIfExist().then(() => {
-
+                 // 初始历史条数作为偏移量
-    },
+                 this.historyOffset = this.messages.length;
+               });
+               // 移除：this.historyOffset = 0;（避免覆盖初始历史的偏移量）
+             },
+             // 新增：组件销毁时清除防抖定时器
+             beforeDestroy() {
+               if (this.scrollTimer) clearTimeout(this.scrollTimer);
+             },
   created() {
     this.messages = [...this.initialMessages]
     this.messageId = this.messages.length
@@ -505,7 +516,18 @@ export default {
       }
       // #endif
     },
-    
+        onScroll(e) {
+          const currentScrollTop = e.detail.scrollTop;
+          this.lastScrollTop = currentScrollTop;
+          // 防抖处理：50ms内只执行一次，避免频繁触发
+          if (this.scrollTimer) clearTimeout(this.scrollTimer);
+          this.scrollTimer = setTimeout(() => {
+            // 滚动到顶部附近（<20px）、不在加载中、显示加载更多时，触发加载
+            if (currentScrollTop < 20 && !this.isLoadingHistory && this.showLoadMore) {
+              this.loadMoreHistory();
+            }
+          }, 50);
+        },
     // 初始化用户头像（支持缓存持久化）
     initUserAvatarData() {
       // 1. 优先读取本地缓存的头像
@@ -927,68 +949,76 @@ export default {
     },
     
     // 加载更多历史消息
-  async loadMoreHistory() {
+ async loadMoreHistory() {
-	  if (!this.currentConversationId) {
+       if (!this.currentConversationId) {
-	      this.currentConversationId = this.getConversationIdFromLocal();
+         this.currentConversationId = this.getConversationIdFromLocal();
-	      aiService.setConversationId(this.currentConversationId);
+         aiService.setConversationId(this.currentConversationId);
-	    }
+       }
-  	if (!this.showLoadMore || !this.currentConversationId || this.isLoadingHistory) {
+       // 防止重复加载
-  		return
+       if (!this.showLoadMore || !this.currentConversationId || this.isLoadingHistory) {
-  	}
+         return;
-  
+       }
-  	this.isLoadingHistory = true
+       this.isFetchingHistory = true;
-  	this.loadingText = '加载历史消息中...'
+       this.isLoadingHistory = true;
-  	this.hasMoreHistory = true
+       this.loadingText = '加载历史消息中...';
-  
+       this.hasMoreHistory = true;
-  	try {
+ 
-  		const response = await aiService.getConversationHistory({
+       try {
-  			conversation_id: this.currentConversationId,
+         // 关键修改：用独立的historyOffset作为偏移量，不再依赖messages.length
-  			limit: 20,
+         const response = await aiService.getConversationHistory({
-  			offset: this.messages.length
+           conversation_id: this.currentConversationId,
-  		})
+           limit: 20,
-  
+           offset: this.historyOffset // 改用独立偏移量
-  		if (response.success && Array.isArray(response.messages)) {
+         });
-  			const historyMessages = response.messages.map(msg => ({
+ 
-  				id: msg.id,
+         if (response.success && Array.isArray(response.messages) && response.messages.length > 0) {
-  				role: msg.role === 'user' ? 'user' : 'ai',
+           const historyMessages = response.messages.map(msg => ({
-  				type: 'text',
+             id: msg.id || `history-${Date.now()}-${Math.random().toString(36).slice(2)}`,
-  				content: msg.content,
+             role: msg.role === 'user' ? 'user' : 'ai',
-  				timestamp: msg.create_time * 1000
+             type: 'text',
-  			}))
+             content: msg.content,
-  
+             timestamp: msg.create_time * 1000
-  			if (historyMessages.length > 0) {
+           }));
-  				this.messages = [...historyMessages, ...this.messages]
+ 
-  
+           // 1. 记录新增消息数量
-  				// 👇 注意：这里加了 async
+           const newMsgCount = historyMessages.length;
-  				this.$nextTick(async () => {
+           // 2. 添加到消息列表开头
-  					const query = uni.createSelectorQuery().in(this)
+           this.messages = [...historyMessages, ...this.messages];
-  					query.select('.chat-messages').boundingClientRect()
+           // 3. 更新历史偏移量（累加，不是覆盖）
-  					query.select('.chat-messages').scrollOffset()
+           this.historyOffset += newMsgCount;
-  
+ 
-  					const res = await new Promise((resolve) => {
+           // 4. 等待DOM渲染后，精准计算滚动位置
-  						query.exec(resolve)
+           await this.$nextTick();
-  					})
+           // 获取新增消息的实际DOM高度
-  
+           const query = uni.createSelectorQuery().in(this);
-  					const currentScrollTop = res[1]?.scrollTop || 0
+           const heightPromises = [];
-  					const avgMessageHeight = 80
+           for (let i = 0; i < newMsgCount; i++) {
-  					const addedHeight = historyMessages.length * avgMessageHeight
+             heightPromises.push(new Promise(resolve => {
-  
+               query.select(`.message-item:nth-child(${i + 1})`).boundingClientRect(rect => {
-  					this.scrollTop = currentScrollTop - addedHeight
+                 resolve(rect ? rect.height + 32 : 0); // 加上消息间距（32rpx）
-  				})
+               }).exec();
-  			}
+             }));
-  		} else {
+           }
-  			this.showLoadMore = false
+           // 计算总高度
-  		}
+           const heights = await Promise.all(heightPromises);
-  	} catch (error) {
+           const totalNewHeight = heights.reduce((sum, h) => sum + h, 0);
-  		console.error('加载历史失败:', error)
+           // 5. 设置scrollTop，保持滚动条在顶部附近
-  		uni.showToast({ title: '加载历史失败', icon: 'none' })
+           this.scrollTop = totalNewHeight;
-  		this.showLoadMore = false
+         } else {
-  	} finally {
+           // 无更多历史
-  		this.isLoadingHistory = false
+           this.showLoadMore = false;
-  		this.hasMoreHistory = false
+         }
-  		this.loadingText = '加载更多历史消息'
+       } catch (error) {
-  	}
+         console.error('加载历史失败:', error);
-  },
+         uni.showToast({ title: '加载历史失败', icon: 'none' });
+         this.showLoadMore = false;
+       } finally {
+         this.isLoadingHistory = false;
+		  this.isFetchingHistory = false;
+         this.hasMoreHistory = false;
+         this.loadingText = '加载更多历史消息';
+       }
+     },
     // 显示更多工具
     showMoreTools() {
       this.showToolsPanel = true