feat(theater): 剧场分类列表服务端分页

lib/core/data/remote/catalog_api.dart

@@ -18,9 +18,10 @@ class CatalogApi {
     return HomeFeed.fromJson(_asMap(await _client.get('/app/discover/feed')));
   }
 
-  /// 内容类型推荐流；types 为空表示推荐全部，cursor 为上一页末条。
+  /// 推荐流；types/categoryId 为空表示不过滤，cursor 为上一页末条。
   Future<FeedPage> feed({
     List<String> types = const [],
+    String? categoryId,
     String? cursor,
     int size = 10,
   }) async {
@@ -30,6 +31,8 @@ class CatalogApi {
           '/app/feed',
           query: {
             if (types.isNotEmpty) 'types': types.join(','),
+            if (categoryId != null && categoryId.isNotEmpty)
+              'categoryId': categoryId,
             if (cursor != null && cursor.isNotEmpty) 'cursor': cursor,
             'size': '$size',
           },

lib/core/data/repositories/catalog_repository.dart

@@ -16,6 +16,7 @@ abstract interface class CatalogRepository {
 
   Future<FeedPage> fetchFeed({
     List<String> types = const [],
+    String? categoryId,
     String? cursor,
     int size = 10,
   });
@@ -37,9 +38,15 @@ class HttpCatalogRepository implements CatalogRepository {
   @override
   Future<FeedPage> fetchFeed({
     List<String> types = const [],
+    String? categoryId,
     String? cursor,
     int size = 10,
-  }) => _api.feed(types: types, cursor: cursor, size: size);
+  }) => _api.feed(
+    types: types,
+    categoryId: categoryId,
+    cursor: cursor,
+    size: size,
+  );
 
   @override
   Future<Drama> fetchDrama(String dramaId) => _api.dramaDetail(dramaId);

lib/core/data/services/theater_feed_controller.dart

@@ -0,0 +1,187 @@
+// Author: fruit.com.cn
+
+import 'dart:async';
+
+import 'package:flutter/foundation.dart';
+
+import '../../data/models/drama.dart';
+import '../../data/repositories/catalog_repository.dart';
+
+/// 剧场页服务端分类列表：按 categoryId 独立缓存、刷新和游标分页。
+class TheaterFeedController extends ChangeNotifier {
+  TheaterFeedController(
+    this._repository, {
+    this.requestTimeout = defaultRequestTimeout,
+  });
+
+  static const int pageSize = 20;
+  static const Duration defaultRequestTimeout = Duration(seconds: 10);
+
+  final CatalogRepository _repository;
+  final Duration requestTimeout;
+  final Map<String?, _CategoryFeedState> _states = {};
+  String? _categoryId;
+  bool _initialized = false;
+  bool _disposed = false;
+
+  String? get categoryId => _categoryId;
+  String? get lastError => _state(_categoryId).lastError;
+  List<Drama> get dramas => _state(_categoryId).dramas;
+  String? get cursor => _state(_categoryId).cursor;
+  bool get hasMore => _state(_categoryId).hasMore;
+  bool get loaded => _state(_categoryId).loaded;
+  bool get loadingMore => _state(_categoryId).loadingMore;
+  bool get loadingFirstPage => !loaded && _state(_categoryId).loading;
+
+  /// 同步切换分类；有缓存先渲染，无缓存时等待或发起首屏请求。
+  Future<void> select(String? next) async {
+    if (_initialized && next == _categoryId) return;
+    _categoryId = next;
+    _initialized = true;
+    _notify();
+
+    final state = _state(next);
+    if (state.dramas.isNotEmpty) {
+      if (!state.loading) {
+        unawaited(_refresh(next, keepData: true));
+      }
+      return;
+    }
+    if (state.loading) {
+      final inFlight = state.inFlight;
+      if (inFlight != null) await inFlight;
+      return;
+    }
+    await _refresh(next, keepData: false);
+  }
+
+  /// 刷新当前分类；失败时保留已有列表。
+  Future<bool> refreshCurrent() async {
+    final state = _state(_categoryId);
+    if (state.loading) {
+      return await state.inFlight ?? false;
+    }
+    return _refresh(_categoryId, keepData: true);
+  }
+
+  /// 加载当前分类下一页并去重追加。
+  Future<void> loadMore() async {
+    final categoryId = _categoryId;
+    final state = _state(categoryId);
+    if (!state.hasMore || state.loadingMore || state.cursor == null) return;
+    final sequence = ++state.requestSeq;
+    state.loadingMore = true;
+    _notifyIfCurrent(categoryId);
+    try {
+      final page = await _repository
+          .fetchFeed(
+            categoryId: categoryId,
+            cursor: state.cursor,
+            size: pageSize,
+          )
+          .timeout(requestTimeout);
+      if (!_acceptSequence(categoryId, sequence)) return;
+      final seen = state.dramas.map((drama) => drama.id).toSet();
+      final appended = page.dramas
+          .where((drama) => seen.add(drama.id))
+          .toList();
+      state
+        ..dramas = List.unmodifiable([...state.dramas, ...appended])
+        ..cursor = page.nextCursor
+        ..hasMore = page.hasMore
+        ..loaded = true
+        ..lastError = null;
+    } catch (error) {
+      if (_acceptSequence(categoryId, sequence)) {
+        state.lastError = error.toString();
+      }
+    } finally {
+      state.loadingMore = false;
+      _notifyIfCurrent(categoryId);
+    }
+  }
+
+  Future<bool> _refresh(String? categoryId, {required bool keepData}) {
+    final state = _state(categoryId);
+    final operation = _performRefresh(categoryId, keepData: keepData);
+    state.inFlight = operation;
+    unawaited(_clearInFlight(state, operation));
+    return operation;
+  }
+
+  Future<bool> _performRefresh(
+    String? categoryId, {
+    required bool keepData,
+  }) async {
+    final state = _state(categoryId);
+    final sequence = ++state.requestSeq;
+    state
+      ..loading = true
+      ..lastError = null;
+    _notifyIfCurrent(categoryId);
+    try {
+      final page = await _repository
+          .fetchFeed(categoryId: categoryId, size: pageSize)
+          .timeout(requestTimeout);
+      if (!_acceptSequence(categoryId, sequence)) return false;
+      state
+        ..dramas = List.unmodifiable(page.dramas)
+        ..cursor = page.nextCursor
+        ..hasMore = page.hasMore
+        ..loaded = true
+        ..loading = false
+        ..lastError = null;
+      _notifyIfCurrent(categoryId);
+      return true;
+    } catch (error) {
+      if (!_acceptSequence(categoryId, sequence)) return false;
+      if (!keepData) state.dramas = const [];
+      state
+        ..loaded = true
+        ..loading = false
+        ..lastError = error.toString();
+      _notifyIfCurrent(categoryId);
+      return false;
+    }
+  }
+
+  Future<void> _clearInFlight(
+    _CategoryFeedState state,
+    Future<bool> operation,
+  ) async {
+    await operation;
+    if (identical(state.inFlight, operation)) state.inFlight = null;
+  }
+
+  _CategoryFeedState _state(String? categoryId) =>
+      _states.putIfAbsent(categoryId, _CategoryFeedState.new);
+
+  bool _acceptSequence(String? categoryId, int sequence) =>
+      !_disposed && _state(categoryId).requestSeq == sequence;
+
+  void _notifyIfCurrent(String? categoryId) {
+    if (!_disposed && categoryId == _categoryId) _notify();
+  }
+
+  void _notify() {
+    if (!_disposed) notifyListeners();
+  }
+
+  @override
+  void dispose() {
+    _disposed = true;
+    super.dispose();
+  }
+}
+
+class _CategoryFeedState {
+  List<Drama> dramas = const [];
+  String? cursor;
+  bool hasMore = true;
+  bool loaded = false;
+  bool loading = false;
+  bool loadingMore = false;
+  String? lastError;
+  int requestSeq = 0;
+  Future<bool>? inFlight;
+}

lib/pages/discover/discover_view.dart

@@ -8,9 +8,11 @@ import 'package:flutter/services.dart';
 import 'package:provider/provider.dart';
 
 import '../../core/data/models/drama.dart';
+import '../../core/data/repositories/catalog_repository.dart';
 import '../../core/data/repositories/search_repository.dart';
 import '../../core/data/services/catalog_retry.dart';
 import '../../core/data/services/category_controller.dart';
+import '../../core/data/services/theater_feed_controller.dart';
 import '../../core/formatting/error_text.dart';
 import '../../core/theme/app_colors.dart';
 import '../../core/theme/app_dimens.dart';
@@ -70,6 +72,7 @@ class DiscoverPage extends StatefulWidget {
 
 class _DiscoverPageState extends State<DiscoverPage> {
   late final DiscoverLogic logic;
+  late final TheaterFeedController theater;
   final ValueNotifier<bool> _headerPinned = ValueNotifier<bool>(false);
   final ScrollController _categoryScroll = ScrollController();
   final Map<String, GlobalKey> _categoryAnchors = {};
@@ -82,13 +85,25 @@ class _DiscoverPageState extends State<DiscoverPage> {
   void initState() {
     super.initState();
     logic = DiscoverBinding().create(search: context.read<SearchRepository>());
+    theater = TheaterFeedController(context.read<CatalogRepository>());
     logic.scroll.addListener(_onScroll);
+    theater.addListener(_onTheaterChanged);
+    unawaited(theater.select(null));
     if (widget.focusSearch) _focusOnFirstFrame();
   }
 
   void _onScroll() {
     final pinned = logic.scroll.hasClients && logic.scroll.offset > 0;
     if (pinned != _headerPinned.value) _headerPinned.value = pinned;
+    if (logic.scroll.hasClients &&
+        !logic.hasSearchQuery &&
+        logic.scroll.position.extentAfter < 400) {
+      unawaited(theater.loadMore());
+    }
+  }
+
+  void _onTheaterChanged() {
+    if (mounted) setState(() {});
   }
 
   void _focusOnFirstFrame() {
@@ -111,6 +126,8 @@ class _DiscoverPageState extends State<DiscoverPage> {
   @override
   void dispose() {
     logic.scroll.removeListener(_onScroll);
+    theater.removeListener(_onTheaterChanged);
+    theater.dispose();
     _categoryScroll.dispose();
     _headerPinned.dispose();
     logic.dispose();
@@ -169,7 +186,8 @@ class _DiscoverPageState extends State<DiscoverPage> {
             child: AppPullToRefresh(
               key: const Key('discover-refresh'),
               edgeOffset: _stickyHeaderHeight + 8,
-              onRefresh: categories.load,
+              onRefresh: () =>
+                  Future.wait([categories.load(), theater.refreshCurrent()]),
               child: ListView(
                 controller: logic.scroll,
                 physics: AppPullToRefresh.physics,
@@ -195,7 +213,7 @@ class _DiscoverPageState extends State<DiscoverPage> {
 
   bool _showStickyHeader(CategoryController categories) {
     if (logic.hasSearchQuery || categories.error != null) return false;
-    return !(categories.loading && categories.feed.sections.isEmpty);
+    return !(categories.loading && categories.categories.isEmpty);
   }
 
   Widget _stickyHeader(AppLocalizations l10n, CategoryController categories) {
@@ -244,7 +262,7 @@ class _DiscoverPageState extends State<DiscoverPage> {
         ),
       ];
     }
-    if (categories.loading && categories.feed.sections.isEmpty) {
+    if (categories.loading && categories.categories.isEmpty) {
       return [_block(const CircularProgressIndicator(strokeWidth: 2))];
     }
     final error = categories.error;
@@ -269,16 +287,35 @@ class _DiscoverPageState extends State<DiscoverPage> {
         ),
       ];
     }
-    return _theaterBlocks(l10n, categories);
+    if (theater.loadingFirstPage) {
+      return [_block(const CircularProgressIndicator(strokeWidth: 2))];
+    }
+    final theaterError = theater.lastError;
+    if (theaterError != null && theater.dramas.isEmpty) {
+      return [
+        _block(
+          EmptyState(
+            key: const Key('home-categories-error'),
+            icon: Icons.cloud_off_rounded,
+            title: errorText(l10n, theaterError, l10n.catalogError),
+            subtitle: l10n.emptyHint,
+            actionLabel: l10n.retry,
+            onAction: () => unawaited(_retryTheater()),
+            footer: kDebugMode
+                ? CatalogDebugInfo(
+                    error: theaterError,
+                    onEditEndpoint: () => unawaited(_editTheaterEndpoint()),
+                  )
+                : null,
+          ),
+        ),
+      ];
+    }
+    return _theaterBlocks(l10n);
   }
 
-  List<Widget> _theaterBlocks(
-    AppLocalizations l10n,
-    CategoryController categories,
-  ) {
-    final dramas = logic.selectedCategoryId == null
-        ? categories.feed.dramas
-        : categories.dramasOf(logic.selectedCategoryId!);
+  List<Widget> _theaterBlocks(AppLocalizations l10n) {
+    final dramas = theater.dramas;
     return [
       _toolbar(l10n),
       if (dramas.isEmpty)
@@ -293,6 +330,17 @@ class _DiscoverPageState extends State<DiscoverPage> {
         )
       else
         DramaGrid(l10n: l10n, dramas: dramas, onOpen: _openDrama),
+      if (theater.loadingMore)
+        const Padding(
+          padding: EdgeInsets.symmetric(vertical: 20),
+          child: Center(
+            child: SizedBox.square(
+              key: Key('theater-load-more'),
+              dimension: 22,
+              child: CircularProgressIndicator(strokeWidth: 2),
+            ),
+          ),
+        ),
     ];
   }
 
@@ -386,6 +434,7 @@ class _DiscoverPageState extends State<DiscoverPage> {
 
   void _selectCategory(String? categoryId) {
     logic.selectCategory(categoryId);
+    unawaited(theater.select(categoryId));
     final id = categoryId ?? 'all';
     _ensuredCategoryId = id;
     WidgetsBinding.instance.addPostFrameCallback((_) {
@@ -523,6 +572,23 @@ class _DiscoverPageState extends State<DiscoverPage> {
     return retryCatalogLoad(reload: categories.load);
   }
 
+  Future<void> _retryTheater() async {
+    await retryCatalogLoad(
+      reload: () async {
+        await theater.refreshCurrent();
+      },
+    );
+  }
+
+  Future<void> _editTheaterEndpoint() {
+    return showCatalogEndpointEditor(
+      context,
+      reload: () async {
+        await theater.refreshCurrent();
+      },
+    );
+  }
+
   Future<void> _editCategoriesEndpoint(CategoryController categories) {
     return showCatalogEndpointEditor(context, reload: categories.load);
   }