feat: 更新教练页面和消息结构，支持附件功能

- 在教练页面中引入附件类型，支持图片、视频和文件的上传和展示
- 重构消息数据结构，确保消息包含附件信息
- 优化消息发送逻辑，支持发送包含图片的消息
- 更新界面样式，提升附件展示效果
- 删除不再使用的旧图标，替换为新的应用图标和启动画面

app/(tabs)/_layout.tsx

@@ -5,9 +5,9 @@ import { Text, TouchableOpacity, View } from 'react-native';
 
 import { IconSymbol } from '@/components/ui/IconSymbol';
 import { Colors } from '@/constants/Colors';
+import { ROUTES } from '@/constants/Routes';
 import { TAB_BAR_BOTTOM_OFFSET, TAB_BAR_HEIGHT } from '@/constants/TabBar';
 import { useColorScheme } from '@/hooks/useColorScheme';
-import { ROUTES } from '@/constants/Routes';
 
 export default function TabLayout() {
   const theme = (useColorScheme() ?? 'light') as 'light' | 'dark';
@@ -16,6 +16,7 @@ export default function TabLayout() {
 
   return (
     <Tabs
+      initialRouteName="coach"
       screenOptions={({ route }) => {
         const routeName = route.name;
         const isSelected = (routeName === 'index' && pathname === ROUTES.TAB_HOME) ||

app/(tabs)/coach.tsx

@@ -35,10 +35,31 @@ import { ActionSheet } from '../../components/ui/ActionSheet';
 
 type Role = 'user' | 'assistant';
 
+// 附件类型枚举
+type AttachmentType = 'image' | 'video' | 'file';
+
+// 附件数据结构
+type MessageAttachment = {
+  id: string;
+  type: AttachmentType;
+  url: string;
+  localUri?: string;  // 本地URI，用于上传中的显示
+  filename?: string;
+  size?: number;
+  duration?: number;  // 视频时长（秒）
+  thumbnail?: string; // 视频缩略图
+  width?: number;
+  height?: number;
+  uploadProgress?: number; // 上传进度 0-1
+  uploadError?: string;    // 上传错误信息
+};
+
+// 重构后的消息数据结构
 type ChatMessage = {
   id: string;
   role: Role;
-  content: string;
+  content: string;           // 文本内容
+  attachments?: MessageAttachment[]; // 附件列表
 };
 
 // 卡片类型常量定义
@@ -256,7 +277,15 @@ export default function CoachScreen() {
         const cached = await loadAiCoachSessionCache();
         if (isMounted && cached && Array.isArray(cached.messages) && cached.messages.length > 0) {
           setConversationId(cached.conversationId);
-          setMessages(cached.messages.filter(msg => msg && typeof msg === 'object' && msg.role && msg.content) as ChatMessage[]);
+          // 确保缓存的消息符合新的 ChatMessage 结构
+          const validMessages = cached.messages
+            .filter(msg => msg && typeof msg === 'object' && msg.role && msg.content)
+            .map(msg => ({
+              ...msg,
+              // 确保 attachments 字段存在，对于旧的缓存消息可能没有这个字段
+              attachments: (msg as any).attachments || undefined,
+            })) as ChatMessage[];
+          setMessages(validMessages);
           setTimeout(() => {
             if (isMounted) scrollToEnd();
           }, 100);
@@ -463,7 +492,14 @@ export default function CoachScreen() {
       }
       const mapped: ChatMessage[] = (detail.messages || [])
         .filter((m) => m.role === 'user' || m.role === 'assistant')
-        .map((m, idx) => ({ id: `${m.role}_${idx}_${Date.now()}`, role: m.role as Role, content: m.content || '' }));
+        .map((m, idx) => ({
+          id: `${m.role}_${idx}_${Date.now()}`,
+          role: m.role as Role,
+          content: m.content || '',
+          // 对于历史消息，暂时不包含附件信息，因为服务器端可能还没有返回附件数据
+          // 如果将来服务器支持返回附件信息，可以在这里添加映射逻辑
+          attachments: undefined,
+        }));
       setConversationId(detail.conversationId);
       setMessages(mapped.length ? mapped : [{ id: 'm_welcome', role: 'assistant', content: generateWelcomeMessage() }]);
       setHistoryVisible(false);
@@ -493,9 +529,9 @@ export default function CoachScreen() {
     ]);
   }
 
-  async function sendStream(text: string) {
+  async function sendStream(text: string, imageUrls: string[] = []) {
     const tokenExists = !!getAuthToken();
-    try { console.log('[AI_CHAT][ui] send start', { tokenExists, conversationId, textPreview: text.slice(0, 50) }); } catch { }
+    try { console.log('[AI_CHAT][ui] send start', { tokenExists, conversationId, textPreview: text.slice(0, 50), imageUrls }); } catch { }
 
     // 终止上一次未完成的流
     if (streamAbortRef.current) {
@@ -510,6 +546,7 @@ export default function CoachScreen() {
     const body = {
       conversationId: cid,
       messages: [...historyForServer, { role: 'user' as const, content: text }],
+      imageUrls: imageUrls.length > 0 ? imageUrls : undefined,
       stream: true,
     };
 
@@ -517,7 +554,19 @@ export default function CoachScreen() {
     const assistantId = `a_${Date.now()}`;
     const userMsgId = `u_${Date.now()}_${Math.random().toString(36).slice(2, 8)}`;
 
-    const userMsg: ChatMessage = { id: userMsgId, role: 'user', content: text };
+    // 构建包含附件的用户消息
+    const attachments = imageUrls.map((url, index) => ({
+      id: `img_${Date.now()}_${index}`,
+      type: 'image' as AttachmentType,
+      url,
+    }));
+
+    const userMsg: ChatMessage = {
+      id: userMsgId,
+      role: 'user',
+      content: text,
+      attachments: attachments.length > 0 ? attachments : undefined,
+    };
     shouldAutoScrollRef.current = isAtBottom;
     setMessages((m) => [...m, userMsg, { id: assistantId, role: 'assistant', content: '' }]);
     pendingAssistantIdRef.current = assistantId;
@@ -614,12 +663,10 @@ export default function CoachScreen() {
     }
 
     try {
-      const urls = selectedImages.map(img => img.uploadedUrl).filter(Boolean);
-      const mdImages = urls.map((u) => `![image](${u})`).join('\n\n');
-      const composed = [trimmed, mdImages].filter(Boolean).join('\n\n');
+      const imageUrls = selectedImages.map(img => img.uploadedUrl).filter(Boolean) as string[];
       setInput('');
       setSelectedImages([]);
-      await sendStream(composed);
+      await sendStream(trimmed, imageUrls);
     } catch (e: any) {
       Alert.alert('发送失败', e?.message || '消息发送失败，请稍后重试');
     }
@@ -706,6 +753,88 @@ export default function CoachScreen() {
     setSelectedImages((prev) => prev.filter((it) => it.id !== id));
   }, []);
 
+  // 渲染单个附件
+  function renderAttachment(attachment: MessageAttachment, isUser: boolean) {
+    const { type, url, localUri, uploadProgress, uploadError, width, height, filename } = attachment;
+
+    if (type === 'image') {
+      const imageUri = url || localUri;
+      if (!imageUri) return null;
+
+      return (
+        <View key={attachment.id} style={styles.attachmentContainer}>
+          <TouchableOpacity
+            accessibilityRole="imagebutton"
+            onPress={() => setPreviewImageUri(imageUri)}
+            style={styles.imageAttachment}
+          >
+            <Image
+              source={{ uri: imageUri }}
+              style={[
+                styles.attachmentImage,
+                width && height ? { aspectRatio: width / height } : {}
+              ]}
+              resizeMode="cover"
+            />
+            {uploadProgress !== undefined && uploadProgress < 1 && (
+              <View style={styles.attachmentProgressOverlay}>
+                <Text style={styles.attachmentProgressText}>
+                  {Math.round(uploadProgress * 100)}%
+                </Text>
+              </View>
+            )}
+            {uploadError && (
+              <View style={styles.attachmentErrorOverlay}>
+                <Text style={styles.attachmentErrorText}>上传失败</Text>
+              </View>
+            )}
+          </TouchableOpacity>
+        </View>
+      );
+    }
+
+    if (type === 'video') {
+      // 视频附件的实现
+      return (
+        <View key={attachment.id} style={styles.attachmentContainer}>
+          <TouchableOpacity style={styles.videoAttachment}>
+            <View style={styles.videoPlaceholder}>
+              <Ionicons name="play-circle" size={48} color="rgba(255,255,255,0.9)" />
+              <Text style={styles.videoFilename}>{filename || '视频文件'}</Text>
+            </View>
+          </TouchableOpacity>
+        </View>
+      );
+    }
+
+    if (type === 'file') {
+      // 文件附件的实现
+      return (
+        <View key={attachment.id} style={styles.attachmentContainer}>
+          <TouchableOpacity style={styles.fileAttachment}>
+            <Ionicons name="document-outline" size={24} color="#687076" />
+            <Text style={styles.fileFilename} numberOfLines={1}>
+              {filename || 'unknown_file'}
+            </Text>
+          </TouchableOpacity>
+        </View>
+      );
+    }
+
+    return null;
+  }
+
+  // 渲染所有附件
+  function renderAttachments(attachments: MessageAttachment[], isUser: boolean) {
+    if (!attachments || attachments.length === 0) return null;
+
+    return (
+      <View style={styles.attachmentsContainer}>
+        {attachments.map(attachment => renderAttachment(attachment, isUser))}
+      </View>
+    );
+  }
+
   function renderItem({ item }: { item: ChatMessage }) {
     const isUser = item.role === 'user';
     return (
@@ -726,6 +855,7 @@ export default function CoachScreen() {
           ]}
         >
           {renderBubbleContent(item)}
+          {renderAttachments(item.attachments || [], isUser)}
         </View>
 
       </Animated.View>
@@ -900,7 +1030,7 @@ export default function CoachScreen() {
 
       // 在对话中插入"确认消息"并发送给教练
       const textMsg = `#记体重：\n\n${val} kg`;
-      await send(textMsg);
+      await sendStream(textMsg);
     } catch (e: any) {
       console.error('[AI_CHAT] Error handling weight submission:', e);
       Alert.alert('保存失败', e?.message || '请稍后重试');
@@ -992,9 +1122,9 @@ export default function CoachScreen() {
       // 移除饮食选择卡片
       setMessages((prev) => prev.filter(msg => msg.id !== currentCardId));
 
-      // 发送包含图片的饮食记录消息
-      const dietMsg = `#记饮食：\n\n![食物照片](${url})`;
-      await send(dietMsg);
+      // 发送包含图片的饮食记录消息，图片通过 imageUrls 参数传递
+      const dietMsg = `#记饮食：请分析这张食物照片的营养成分和热量`;
+      await sendStream(dietMsg, [url]);
     } catch (uploadError) {
       console.error('[DIET] 图片上传失败:', uploadError);
       Alert.alert('上传失败', '图片上传失败，请重试');
@@ -1031,7 +1161,7 @@ export default function CoachScreen() {
 
       // 发送饮食记录消息
       const dietMsg = `记录了今日饮食：${trimmedText}`;
-      await send(dietMsg);
+      await sendStream(dietMsg);
     } catch (e: any) {
       console.error('[DIET] 提交饮食记录失败:', e);
       Alert.alert('提交失败', e?.message || '提交失败，请重试');
@@ -1278,7 +1408,6 @@ export default function CoachScreen() {
         options={[
           { id: 'camera', title: '拍照', onPress: handleCameraPhoto },
           { id: 'library', title: '从相册选择', onPress: handleLibraryPhoto },
-          { id: 'cancel', title: '取消', onPress: () => setShowDietPhotoActionSheet(false) }
         ]}
       />
     </View>
@@ -1663,6 +1792,87 @@ const styles = StyleSheet.create({
     width: '100%',
     height: '100%',
   },
+  // 附件相关样式
+  attachmentsContainer: {
+    marginTop: 8,
+    gap: 6,
+  },
+  attachmentContainer: {
+    marginBottom: 4,
+  },
+  imageAttachment: {
+    borderRadius: 12,
+    overflow: 'hidden',
+    position: 'relative',
+  },
+  attachmentImage: {
+    width: '100%',
+    minHeight: 120,
+    maxHeight: 200,
+    borderRadius: 12,
+  },
+  attachmentProgressOverlay: {
+    position: 'absolute',
+    top: 0,
+    left: 0,
+    right: 0,
+    bottom: 0,
+    backgroundColor: 'rgba(0,0,0,0.4)',
+    alignItems: 'center',
+    justifyContent: 'center',
+    borderRadius: 12,
+  },
+  attachmentProgressText: {
+    color: '#fff',
+    fontSize: 14,
+    fontWeight: '600',
+  },
+  attachmentErrorOverlay: {
+    position: 'absolute',
+    top: 0,
+    left: 0,
+    right: 0,
+    bottom: 0,
+    backgroundColor: 'rgba(255,0,0,0.4)',
+    alignItems: 'center',
+    justifyContent: 'center',
+    borderRadius: 12,
+  },
+  attachmentErrorText: {
+    color: '#fff',
+    fontSize: 12,
+    fontWeight: '600',
+  },
+  videoAttachment: {
+    borderRadius: 12,
+    overflow: 'hidden',
+    backgroundColor: 'rgba(0,0,0,0.1)',
+  },
+  videoPlaceholder: {
+    height: 120,
+    alignItems: 'center',
+    justifyContent: 'center',
+    backgroundColor: 'rgba(0,0,0,0.6)',
+  },
+  videoFilename: {
+    color: '#fff',
+    fontSize: 12,
+    marginTop: 4,
+    textAlign: 'center',
+  },
+  fileAttachment: {
+    flexDirection: 'row',
+    alignItems: 'center',
+    padding: 12,
+    backgroundColor: 'rgba(0,0,0,0.06)',
+    borderRadius: 8,
+    gap: 8,
+  },
+  fileFilename: {
+    flex: 1,
+    fontSize: 14,
+    color: '#192126',
+  },
 });
 
 const markdownStyles = {