feat(pagination): implement cursor-based pagination across the app

Add useCursorPagination hook and update multiple screens and services
to use cursor-based pagination for better performance and consistency.

- Add useCursorPagination hook with deduplication and caching support
- Add cursor pagination types to infrastructure layer
- Refactor HomeScreen, PostDetailScreen, SearchScreen for posts/comments
- Refactor GroupMembersScreen, JoinGroupScreen for groups/members
- Refactor MessageListScreen, NotificationsScreen for messages
- Update post, message, group, comment, notification services with cursor endpoints
- Add CursorPaginationRequest/Response DTOs
- Remove deprecated OPTIMIZATION_DESIGN.md documentation

src/screens/home/HomeScreen.tsx

@@ -13,7 +13,6 @@ import {
   RefreshControl,
   StatusBar,
   TouchableOpacity,
-  NativeScrollEvent,
   NativeSyntheticEvent,
   Alert,
   Clipboard,
@@ -33,6 +32,8 @@ import { PostCard, TabBar, SearchBar } from '../../components/business';
 import { Loading, EmptyState, Text, ImageGallery, ImageGridItem, ResponsiveGrid } from '../../components/common';
 import { HomeStackParamList, RootStackParamList } from '../../navigation/types';
 import { useResponsive, useResponsiveSpacing } from '../../hooks/useResponsive';
+import { useCursorPagination } from '../../hooks/useCursorPagination';
+import { CursorPaginationRequest } from '../../types/dto';
 import { SearchScreen } from './SearchScreen';
 import { CreatePostScreen } from '../create/CreatePostScreen';
 import { navigationService } from '../../infrastructure/navigation/navigationService';
@@ -42,8 +43,6 @@ type NavigationProp = NativeStackNavigationProp<HomeStackParamList, 'Home'> & Na
 const TABS = ['推荐', '关注', '热门', '最新'];
 const TAB_ICONS = ['compass-outline', 'account-heart-outline', 'fire', 'clock-outline'];
 const DEFAULT_PAGE_SIZE = 20;
-const SCROLL_BOTTOM_THRESHOLD = 240;
-const LOAD_MORE_COOLDOWN_MS = 800;
 const SWIPE_TRANSLATION_THRESHOLD = 40;
 const SWIPE_COOLDOWN_MS = 300;
 const MOBILE_TAB_BAR_HEIGHT = 64;
@@ -51,11 +50,12 @@ const MOBILE_TAB_FLOATING_MARGIN = 12;
 const MOBILE_FAB_GAP = 12;
 
 type ViewMode = 'list' | 'grid';
+type PostType = 'recommend' | 'follow' | 'hot' | 'latest';
 
 export const HomeScreen: React.FC = () => {
   const navigation = useNavigation<NavigationProp>();
   const insets = useSafeAreaInsets();
-  const { fetchPosts, likePost, unlikePost, favoritePost, unfavoritePost, posts: storePosts } = useUserStore();
+  const { likePost, unlikePost, favoritePost, unfavoritePost, posts: storePosts } = useUserStore();
   const currentUser = useCurrentUser();
   
   // 使用响应式 hook
@@ -65,9 +65,6 @@ export const HomeScreen: React.FC = () => {
     isTablet, 
     isDesktop, 
     isWideScreen,
-    breakpoint,
-    orientation,
-    isLandscape 
   } = useResponsive();
   
   // 响应式间距
@@ -75,12 +72,6 @@ export const HomeScreen: React.FC = () => {
   const responsivePadding = useResponsiveSpacing({ xs: 8, sm: 12, md: 16, lg: 24, xl: 32 });
   
   const [activeIndex, setActiveIndex] = useState(0);
-  const [posts, setPosts] = useState<Post[]>([]);
-  const [loading, setLoading] = useState(true);
-  const [refreshing, setRefreshing] = useState(false);
-  const [loadingMore, setLoadingMore] = useState(false);
-  const [page, setPage] = useState(1);
-  const [hasMore, setHasMore] = useState(true);
   const [viewMode, setViewMode] = useState<ViewMode>('list');
   
   // 图片查看器状态
@@ -95,18 +86,56 @@ export const HomeScreen: React.FC = () => {
   const [showCreatePost, setShowCreatePost] = useState(false);
   
   // 用于跟踪当前页面显示的帖子 ID，以便从 store 同步状态
-  const postIdsRef = React.useRef<Set<string>>(new Set());
-  const inFlightRequestKeysRef = React.useRef<Set<string>>(new Set());
-  const lastLoadMoreTriggerAtRef = useRef(0);
+  const postIdsRef = useRef<Set<string>>(new Set());
   const lastSwipeAtRef = useRef(0);
 
-  // 用 ref 同步关键状态，避免 onWaterfallScroll 的陈旧闭包问题
-  const pageRef = useRef(page);
-  const loadingMoreRef = useRef(loadingMore);
-  const hasMoreRef = useRef(hasMore);
-  pageRef.current = page;
-  loadingMoreRef.current = loadingMore;
-  hasMoreRef.current = hasMore;
+  // 获取当前 tab 对应的帖子类型
+  const getPostType = useCallback((): PostType => {
+    switch (activeIndex) {
+      case 0: return 'recommend';
+      case 1: return 'follow';
+      case 2: return 'hot';
+      case 3: return 'latest';
+      default: return 'recommend';
+    }
+  }, [activeIndex]);
+
+  // 使用游标分页获取帖子列表
+  const {
+    items: posts,
+    isLoading,
+    isRefreshing,
+    hasMore,
+    error,
+    loadMore,
+    refresh,
+  } = useCursorPagination<Post, { post_type: PostType }>(
+    async ({ cursor, pageSize, extraParams }) => {
+      const params: CursorPaginationRequest = {
+        cursor,
+        page_size: pageSize,
+        post_type: extraParams?.post_type,
+      };
+      const response = await postService.getPostsCursor(params);
+      return response;
+    },
+    { pageSize: DEFAULT_PAGE_SIZE },
+    { post_type: getPostType() }
+  );
+
+  // Tab 切换时刷新数据
+  useEffect(() => {
+    refresh();
+  }, [activeIndex]);
+
+  // 同步 store 中的帖子状态到本地（用于点赞、收藏等状态更新）
+  useEffect(() => {
+    if (posts.length === 0) return;
+    
+    // 更新 postIdsRef
+    const currentPostIds = new Set(posts.map(p => p.id));
+    postIdsRef.current = currentPostIds;
+  }, [posts, storePosts]);
 
   // 根据屏幕尺寸确定网格列数
   const gridColumns = useMemo(() => {
@@ -154,147 +183,6 @@ export const HomeScreen: React.FC = () => {
     return insets.bottom + MOBILE_TAB_BAR_HEIGHT + MOBILE_TAB_FLOATING_MARGIN + MOBILE_FAB_GAP - MOBILE_TAB_BAR_HEIGHT;
   }, [isMobile, insets.bottom]);
 
-  const appendUniquePosts = useCallback((prevPosts: Post[], incomingPosts: Post[]) => {
-    if (incomingPosts.length === 0) return prevPosts;
-    const seenIds = new Set(prevPosts.map(item => item.id));
-    const dedupedIncoming = incomingPosts.filter(item => {
-      if (seenIds.has(item.id)) return false;
-      seenIds.add(item.id);
-      return true;
-    });
-    return dedupedIncoming.length > 0 ? [...prevPosts, ...dedupedIncoming] : prevPosts;
-  }, []);
-
-  const uniquePostsById = useCallback((items: Post[]) => {
-    if (items.length <= 1) return items;
-    const map = new Map<string, Post>();
-    for (const item of items) {
-      map.set(item.id, item);
-    }
-    return Array.from(map.values());
-  }, []);
-
-  const getPostType = (): 'recommend' | 'follow' | 'hot' | 'latest' => {
-    switch (activeIndex) {
-      case 0: return 'recommend';
-      case 1: return 'follow';
-      case 2: return 'hot';
-      case 3: return 'latest';
-      default: return 'recommend';
-    }
-  };
-
-  // 加载帖子列表
-  const loadPosts = useCallback(async (pageNum: number = 1, isRefresh: boolean = false) => {
-    const postType = getPostType();
-    const requestKey = `${postType}:${pageNum}`;
-    if (inFlightRequestKeysRef.current.has(requestKey)) {
-      return;
-    }
-
-    try {
-      inFlightRequestKeysRef.current.add(requestKey);
-      if (isRefresh) {
-        setRefreshing(true);
-      } else if (pageNum === 1) {
-        setLoading(true);
-      } else {
-        setLoadingMore(true);
-      }
-
-      const response = await fetchPosts(postType, pageNum);
-      const newPosts = response.list || [];
-      
-      if (isRefresh) {
-        setPosts(uniquePostsById(newPosts));
-        setPage(1);
-      } else if (pageNum === 1) {
-        setPosts(uniquePostsById(newPosts));
-        setPage(1);
-      } else {
-        setPosts(prev => appendUniquePosts(prev, newPosts));
-        setPage(pageNum);
-      }
-
-      const hasMoreByPage = response.total_pages > 0 ? response.page < response.total_pages : false;
-      const hasMoreBySize = newPosts.length >= (response.page_size || DEFAULT_PAGE_SIZE);
-      setHasMore(hasMoreByPage || hasMoreBySize);
-    } catch (error) {
-      console.error('Failed to load posts:', error);
-    } finally {
-      inFlightRequestKeysRef.current.delete(requestKey);
-      setLoading(false);
-      setRefreshing(false);
-      setLoadingMore(false);
-    }
-  }, [fetchPosts, activeIndex, appendUniquePosts, uniquePostsById]);
-
-  // 切换Tab时重新加载
-  useEffect(() => {
-    loadPosts(1, true);
-  }, [activeIndex]);
-
-  // 同步 store 中的帖子状态到本地（用于点赞、收藏等状态更新）
-  useEffect(() => {
-    if (posts.length === 0) return;
-    
-    // 更新 postIdsRef
-    const currentPostIds = new Set(posts.map(p => p.id));
-    postIdsRef.current = currentPostIds;
-    
-    // 从 store 中找到对应的帖子并同步状态
-    let hasChanges = false;
-    const updatedPosts = posts.map(localPost => {
-      const storePost = storePosts.find(sp => sp.id === localPost.id);
-      if (storePost && (
-        storePost.is_liked !== localPost.is_liked ||
-        storePost.is_favorited !== localPost.is_favorited ||
-        storePost.likes_count !== localPost.likes_count ||
-        storePost.favorites_count !== localPost.favorites_count
-      )) {
-        hasChanges = true;
-        return {
-          ...localPost,
-          is_liked: storePost.is_liked,
-          is_favorited: storePost.is_favorited,
-          likes_count: storePost.likes_count,
-          favorites_count: storePost.favorites_count,
-        };
-      }
-      return localPost;
-    });
-    
-    if (hasChanges) {
-      setPosts(updatedPosts);
-    }
-  }, [storePosts]);
-
-  // 下拉刷新
-  const onRefresh = useCallback(() => {
-    loadPosts(1, true);
-  }, [loadPosts]);
-
-  // 上拉加载更多
-  const onEndReached = useCallback(() => {
-    if (!loadingMoreRef.current && hasMoreRef.current) {
-      loadPosts(pageRef.current + 1);
-    }
-  }, [loadPosts]);
-
-  const onWaterfallScroll = useCallback((event: NativeSyntheticEvent<NativeScrollEvent>) => {
-    if (loadingMoreRef.current || !hasMoreRef.current) return;
-    const { contentOffset, contentSize, layoutMeasurement } = event.nativeEvent;
-    const distanceToBottom = contentSize.height - (contentOffset.y + layoutMeasurement.height);
-    const now = Date.now();
-    if (distanceToBottom <= SCROLL_BOTTOM_THRESHOLD) {
-      if (now - lastLoadMoreTriggerAtRef.current < LOAD_MORE_COOLDOWN_MS) {
-        return;
-      }
-      lastLoadMoreTriggerAtRef.current = now;
-      loadPosts(pageRef.current + 1);
-    }
-  }, [loadPosts]);
-
   // 切换视图模式
   const toggleViewMode = () => {
     setViewMode(prev => prev === 'list' ? 'grid' : 'list');
@@ -375,27 +263,27 @@ export const HomeScreen: React.FC = () => {
     if (!post?.id) return;
     try {
       await postService.sharePost(post.id);
-    } catch (error) {
-      console.error('上报分享次数失败:', error);
+    } catch (shareError) {
+      console.error('上报分享次数失败:', shareError);
     }
     const postUrl = `https://browser.littlelan.cn/posts/${encodeURIComponent(post.id)}`;
     Clipboard.setString(postUrl);
     Alert.alert('已复制', '帖子链接已复制到剪贴板');
   };
 
-  // 删除帖子
+  // 删除帖子 - 由于 posts 来自 Hook，需要刷新列表
   const handleDeletePost = async (postId: string) => {
     try {
       const success = await postService.deletePost(postId);
       if (success) {
-        // 从列表中移除已删除的帖子
-        setPosts(prev => prev.filter(p => p.id !== postId));
+        // 刷新列表以移除已删除的帖子
+        refresh();
       } else {
         console.error('删除帖子失败');
       }
-    } catch (error) {
-      console.error('删除帖子失败:', error);
-      throw error; // 重新抛出错误，让 PostCard 处理错误提示
+    } catch (deleteError) {
+      console.error('删除帖子失败:', deleteError);
+      throw deleteError; // 重新抛出错误，让 PostCard 处理错误提示
     }
   };
 
@@ -545,12 +433,11 @@ export const HomeScreen: React.FC = () => {
             }
           ]}
           showsVerticalScrollIndicator={false}
-          onScroll={onWaterfallScroll}
           scrollEventThrottle={100}
           refreshControl={
             <RefreshControl
-              refreshing={refreshing}
-              onRefresh={onRefresh}
+              refreshing={isRefreshing}
+              onRefresh={refresh}
               colors={[colors.primary.main]}
               tintColor={colors.primary.main}
             />
@@ -594,7 +481,7 @@ export const HomeScreen: React.FC = () => {
 
   // 渲染空状态
   const renderEmpty = () => {
-    if (loading) return null;
+    if (isLoading) return null;
     
     return (
       <EmptyState
@@ -628,16 +515,16 @@ export const HomeScreen: React.FC = () => {
         showsVerticalScrollIndicator={false}
         refreshControl={
           <RefreshControl
-            refreshing={refreshing}
-            onRefresh={onRefresh}
+            refreshing={isRefreshing}
+            onRefresh={refresh}
             colors={[colors.primary.main]}
             tintColor={colors.primary.main}
           />
         }
-        onEndReached={onEndReached}
+        onEndReached={loadMore}
         onEndReachedThreshold={0.3}
         ListEmptyComponent={renderEmpty}
-        ListFooterComponent={loadingMore ? <Loading size="sm" /> : null}
+        ListFooterComponent={isLoading ? <Loading size="sm" /> : null}
       />
     );
   };