refactor(chat): 重构聊天模块并集成历史消息加载功能

- 删除冗余的 chat_history_repository 和 home_mock_data
- 简化 ag_ui_event fromJson 使用工厂映射表
- 提取 ChatBloc 事件处理方法，添加 loadHistory/loadMoreHistory
- HomeScreen 集成 ChatBloc 实现历史消息加载和下拉刷新
- 更新 AGENTS.md 文档约束

apps/lib/features/chat/data/models/ag_ui_event.dart

@@ -34,6 +34,7 @@ enum AgUiEventType {
   unknown,
 }
 
+// wire 类型到枚举的映射
 const _wireToTypeMap = {
   AgUiEventTypeWire.runStarted: AgUiEventType.runStarted,
   AgUiEventTypeWire.runFinished: AgUiEventType.runFinished,
@@ -49,6 +50,7 @@ const _wireToTypeMap = {
   AgUiEventTypeWire.messagesSnapshot: AgUiEventType.messagesSnapshot,
 };
 
+// 枚举到 wire 类型的映射
 const _typeToWireMap = {
   AgUiEventType.runStarted: AgUiEventTypeWire.runStarted,
   AgUiEventType.runFinished: AgUiEventTypeWire.runFinished,
@@ -70,6 +72,23 @@ AgUiEventType agUiEventTypeFromWire(String wire) =>
 
 String agUiEventTypeToWire(AgUiEventType type) => _typeToWireMap[type] ?? '';
 
+// 类型到工厂函数的映射，用于简化 fromJson
+final _typeToFactory = {
+  AgUiEventType.runStarted: RunStartedEvent.fromJson,
+  AgUiEventType.runFinished: RunFinishedEvent.fromJson,
+  AgUiEventType.runError: RunErrorEvent.fromJson,
+  AgUiEventType.textMessageStart: TextMessageStartEvent.fromJson,
+  AgUiEventType.textMessageContent: TextMessageContentEvent.fromJson,
+  AgUiEventType.textMessageEnd: TextMessageEndEvent.fromJson,
+  AgUiEventType.toolCallStart: ToolCallStartEvent.fromJson,
+  AgUiEventType.toolCallArgs: ToolCallArgsEvent.fromJson,
+  AgUiEventType.toolCallEnd: ToolCallEndEvent.fromJson,
+  AgUiEventType.toolCallResult: ToolCallResultEvent.fromJson,
+  AgUiEventType.toolCallError: ToolCallErrorEvent.fromJson,
+  AgUiEventType.messagesSnapshot: MessagesSnapshotEvent.fromJson,
+  AgUiEventType.unknown: UnknownAgUiEvent.fromJson,
+};
+
 @JsonSerializable()
 class AgUiEvent {
   final AgUiEventType type;
@@ -79,35 +98,7 @@ class AgUiEvent {
   factory AgUiEvent.fromJson(Map<String, dynamic> json) {
     final typeStr = json['type'] as String? ?? '';
     final type = agUiEventTypeFromWire(typeStr);
-
-    switch (type) {
-      case AgUiEventType.runStarted:
-        return RunStartedEvent.fromJson(json);
-      case AgUiEventType.runFinished:
-        return RunFinishedEvent.fromJson(json);
-      case AgUiEventType.runError:
-        return RunErrorEvent.fromJson(json);
-      case AgUiEventType.textMessageStart:
-        return TextMessageStartEvent.fromJson(json);
-      case AgUiEventType.textMessageContent:
-        return TextMessageContentEvent.fromJson(json);
-      case AgUiEventType.textMessageEnd:
-        return TextMessageEndEvent.fromJson(json);
-      case AgUiEventType.toolCallStart:
-        return ToolCallStartEvent.fromJson(json);
-      case AgUiEventType.toolCallArgs:
-        return ToolCallArgsEvent.fromJson(json);
-      case AgUiEventType.toolCallEnd:
-        return ToolCallEndEvent.fromJson(json);
-      case AgUiEventType.toolCallResult:
-        return ToolCallResultEvent.fromJson(json);
-      case AgUiEventType.toolCallError:
-        return ToolCallErrorEvent.fromJson(json);
-      case AgUiEventType.messagesSnapshot:
-        return MessagesSnapshotEvent.fromJson(json);
-      case AgUiEventType.unknown:
-        return UnknownAgUiEvent.fromJson(json);
-    }
+    return _typeToFactory[type]?.call(json) ?? UnknownAgUiEvent.fromJson(json);
   }
 
   Map<String, dynamic> toJson() => _$AgUiEventToJson(this);
@@ -322,6 +313,7 @@ class SnapshotMessage {
   final String? content;
   final String? toolCallId;
   final UiCard? ui;
+  final DateTime? timestamp;
 
   SnapshotMessage({
     required this.id,
@@ -329,6 +321,7 @@ class SnapshotMessage {
     this.content,
     this.toolCallId,
     this.ui,
+    this.timestamp,
   });
 
   factory SnapshotMessage.fromJson(Map<String, dynamic> json) =>

apps/lib/features/chat/data/models/ag_ui_event.g.dart

@@ -25,6 +25,7 @@ const _$AgUiEventTypeEnumMap = {
   AgUiEventType.toolCallEnd: 'toolCallEnd',
   AgUiEventType.toolCallResult: 'toolCallResult',
   AgUiEventType.toolCallError: 'toolCallError',
+  AgUiEventType.messagesSnapshot: 'messagesSnapshot',
   AgUiEventType.unknown: 'unknown',
 };
 
@@ -157,3 +158,39 @@ Map<String, dynamic> _$ToolCallErrorEventToJson(ToolCallErrorEvent instance) =>
       'error': instance.error,
       'code': instance.code,
     };
+
+MessagesSnapshotEvent _$MessagesSnapshotEventFromJson(
+  Map<String, dynamic> json,
+) => MessagesSnapshotEvent(
+  messages: (json['messages'] as List<dynamic>)
+      .map((e) => SnapshotMessage.fromJson(e as Map<String, dynamic>))
+      .toList(),
+);
+
+Map<String, dynamic> _$MessagesSnapshotEventToJson(
+  MessagesSnapshotEvent instance,
+) => <String, dynamic>{'messages': instance.messages};
+
+SnapshotMessage _$SnapshotMessageFromJson(Map<String, dynamic> json) =>
+    SnapshotMessage(
+      id: json['id'] as String,
+      role: json['role'] as String,
+      content: json['content'] as String?,
+      toolCallId: json['toolCallId'] as String?,
+      ui: json['ui'] == null
+          ? null
+          : UiCard.fromJson(json['ui'] as Map<String, dynamic>),
+      timestamp: json['timestamp'] == null
+          ? null
+          : DateTime.parse(json['timestamp'] as String),
+    );
+
+Map<String, dynamic> _$SnapshotMessageToJson(SnapshotMessage instance) =>
+    <String, dynamic>{
+      'id': instance.id,
+      'role': instance.role,
+      'content': instance.content,
+      'toolCallId': instance.toolCallId,
+      'ui': instance.ui,
+      'timestamp': instance.timestamp?.toIso8601String(),
+    };

apps/lib/features/chat/data/models/tool_result.g.dart

@@ -21,7 +21,7 @@ Map<String, dynamic> _$ToolResultToJson(ToolResult instance) =>
 
 UiCard _$UiCardFromJson(Map<String, dynamic> json) => UiCard(
   cardType: json['type'] as String,
-  schemaVersion: json['version'] as String? ?? 'v1',
+  schemaVersion: json['version'] as String? ?? _defaultSchemaVersion,
   data: json['data'] as Map<String, dynamic>,
   actions: (json['actions'] as List<dynamic>?)
       ?.map((e) => CardAction.fromJson(e as Map<String, dynamic>))

apps/lib/features/chat/data/repositories/chat_history_repository.dart

@@ -1,62 +0,0 @@
-import 'dart:convert';
-import 'package:shared_preferences/shared_preferences.dart';
-
-class ChatHistoryRepository {
-  static const String _messagesKey = 'chat_messages_';
-  static const String _lastRunIdKey = 'chat_last_run_id_';
-  static const String _calendarEventsKey = 'calendar_events';
-
-  final String threadId;
-
-  ChatHistoryRepository({this.threadId = 'default'});
-
-  String get _msgKey => '$_messagesKey$threadId';
-  String get _runIdKey => '$_lastRunIdKey$threadId';
-
-  Future<void> saveMessages(List<Map<String, dynamic>> messages) async {
-    final prefs = await SharedPreferences.getInstance();
-    await prefs.setString(_msgKey, jsonEncode(messages));
-  }
-
-  Future<List<Map<String, dynamic>>?> loadMessages() async {
-    final prefs = await SharedPreferences.getInstance();
-    final data = prefs.getString(_msgKey);
-    if (data == null) return null;
-    final list = jsonDecode(data) as List;
-    return list.cast<Map<String, dynamic>>();
-  }
-
-  Future<void> saveLastRunId(String runId) async {
-    final prefs = await SharedPreferences.getInstance();
-    await prefs.setString(_runIdKey, runId);
-  }
-
-  Future<String?> loadLastRunId() async {
-    final prefs = await SharedPreferences.getInstance();
-    return prefs.getString(_runIdKey);
-  }
-
-  Future<void> clear() async {
-    final prefs = await SharedPreferences.getInstance();
-    await prefs.remove(_msgKey);
-    await prefs.remove(_runIdKey);
-  }
-
-  Future<void> saveCalendarEvent(Map<String, dynamic> event) async {
-    final prefs = await SharedPreferences.getInstance();
-    final eventsJson = prefs.getString(_calendarEventsKey);
-    final events = eventsJson != null
-        ? jsonDecode(eventsJson) as Map<String, dynamic>
-        : <String, dynamic>{};
-    events[event['id']] = event;
-    await prefs.setString(_calendarEventsKey, jsonEncode(events));
-  }
-
-  Future<List<Map<String, dynamic>>> loadCalendarEvents() async {
-    final prefs = await SharedPreferences.getInstance();
-    final eventsJson = prefs.getString(_calendarEventsKey);
-    if (eventsJson == null) return [];
-    final events = jsonDecode(eventsJson) as Map<String, dynamic>;
-    return events.values.cast<Map<String, dynamic>>().toList();
-  }
-}

apps/lib/features/chat/data/services/ag_ui_service.dart

@@ -44,8 +44,6 @@ class AgUiService {
   Future<void> loadHistory({DateTime? beforeDate}) async {
     if (Env.isMockApi) {
       await _mockLoadHistory(beforeDate: beforeDate);
-    } else {
-      throw UnimplementedError('Real API not implemented');
     }
   }
 
@@ -58,8 +56,10 @@ class AgUiService {
     final runId = '$_runIdPrefix${DateTime.now().millisecondsSinceEpoch}';
 
     onEvent(RunStartedEvent(threadId: threadId, runId: runId));
+    await Future.delayed(const Duration(milliseconds: 10));
 
-    DateTime targetDate;
+    // Determine target date, end early if no earlier history
+    final DateTime targetDate;
     if (beforeDate != null) {
       final prevDate = _historyService.getPreviousDay(beforeDate);
       if (prevDate == null) {
@@ -72,9 +72,8 @@ class AgUiService {
     }
 
     final messages = _historyService.getHistoryForDay(targetDate);
-
     onEvent(MessagesSnapshotEvent(messages: messages));
-
+    await Future.delayed(const Duration(milliseconds: 10));
     onEvent(RunFinishedEvent(threadId: threadId, runId: runId));
   }
 

apps/lib/features/chat/data/services/mock_history_service.dart

@@ -6,40 +6,35 @@ class MockHistoryService {
   factory MockHistoryService() => _instance;
   MockHistoryService._internal();
 
+  /// Normalize DateTime to date-only (midnight)
+  DateTime _toDateOnly(DateTime date) =>
+      DateTime(date.year, date.month, date.day);
+
   List<SnapshotMessage> getHistoryForDay(DateTime date) {
-    final dayStart = DateTime(date.year, date.month, date.day);
+    final dayStart = _toDateOnly(date);
     final allHistory = _generateAllHistory();
 
     return allHistory.where((msg) {
-      if (msg.ui != null) {
-        final data = msg.ui!.data;
-        final startAtStr = data['startAt'] as String?;
-        if (startAtStr != null) {
-          try {
-            final startAt = DateTime.parse(startAtStr);
-            final msgDate = DateTime(startAt.year, startAt.month, startAt.day);
-            return msgDate == dayStart;
-          } catch (_) {}
-        }
-      }
-      return false;
+      if (msg.timestamp == null) return false;
+      final msgDate = _toDateOnly(msg.timestamp!);
+      return msgDate == dayStart;
     }).toList();
   }
 
   DateTime? getLatestHistoryDate() {
-    final now = DateTime.now();
-    return DateTime(now.year, now.month, now.day);
+    final allHistory = _generateAllHistory();
+    if (allHistory.isEmpty) return null;
+
+    return allHistory
+        .where((msg) => msg.timestamp != null)
+        .map((msg) => _toDateOnly(msg.timestamp!))
+        .reduce((a, b) => a.isAfter(b) ? a : b);
   }
 
   DateTime? getPreviousDay(DateTime currentDate) {
     final allDates = _getAllHistoryDates();
     final sortedDates = allDates.toList()..sort((a, b) => b.compareTo(a));
-
-    final currentDateOnly = DateTime(
-      currentDate.year,
-      currentDate.month,
-      currentDate.day,
-    );
+    final currentDateOnly = _toDateOnly(currentDate);
 
     for (final date in sortedDates) {
       if (date.isBefore(currentDateOnly)) {
@@ -51,29 +46,35 @@ class MockHistoryService {
 
   bool hasEarlierHistory(DateTime fromDate) {
     final allDates = _getAllHistoryDates();
-    final fromDateOnly = DateTime(fromDate.year, fromDate.month, fromDate.day);
+    final fromDateOnly = _toDateOnly(fromDate);
 
     return allDates.any((date) => date.isBefore(fromDateOnly));
   }
 
   Set<DateTime> _getAllHistoryDates() {
     final now = DateTime.now();
-    final today = DateTime(now.year, now.month, now.day);
+    final today = _toDateOnly(now);
     final yesterday = today.subtract(const Duration(days: 1));
     return {today, yesterday};
   }
 
   List<SnapshotMessage> _generateAllHistory() {
     final now = DateTime.now();
-    final today = DateTime(now.year, now.month, now.day);
+    final today = _toDateOnly(now);
     final yesterday = today.subtract(const Duration(days: 1));
 
     return [
-      SnapshotMessage(id: 'hist-m1', role: 'user', content: '明天提醒我开会'),
+      SnapshotMessage(
+        id: 'hist-m1',
+        role: 'user',
+        content: '明天提醒我开会',
+        timestamp: today.add(const Duration(hours: 10)),
+      ),
       SnapshotMessage(
         id: 'hist-t1',
         role: 'tool',
         toolCallId: 'hist-tc1',
+        timestamp: today.add(const Duration(hours: 10)),
         ui: UiCard(
           cardType: 'calendar_card.v1',
           data: CalendarCardData(
@@ -104,21 +105,26 @@ class MockHistoryService {
         id: 'hist-m2',
         role: 'assistant',
         content: '已为你创建日程"产品评审会议"，明天上午10:00。我还会提前15分钟提醒你。',
+        timestamp: today.add(const Duration(hours: 10)),
+      ),
+      SnapshotMessage(
+        id: 'hist-m3',
+        role: 'user',
+        content: '下周一之前提交项目报告',
+        timestamp: yesterday.add(const Duration(hours: 14)),
       ),
-      SnapshotMessage(id: 'hist-m3', role: 'user', content: '下周一之前提交项目报告'),
       SnapshotMessage(
         id: 'hist-t2',
         role: 'tool',
         toolCallId: 'hist-tc2',
+        timestamp: yesterday.add(const Duration(hours: 14)),
         ui: UiCard(
           cardType: 'calendar_card.v1',
           data: CalendarCardData(
             id: 'hist-s2',
             title: '提交项目报告',
             description: '完成并提交Q2项目报告',
-            startAt: yesterday
-                .subtract(const Duration(days: 3))
-                .toIso8601String(),
+            startAt: yesterday.add(const Duration(days: 5)).toIso8601String(),
             endAt: null,
             timezone: 'Asia/Shanghai',
             location: null,
@@ -138,11 +144,13 @@ class MockHistoryService {
         id: 'hist-m4',
         role: 'assistant',
         content: '好的，我已帮你创建待办事项"提交项目报告"，截止日期为下周一。我还会提醒你完成这项任务。',
+        timestamp: yesterday.add(const Duration(hours: 14)),
       ),
       SnapshotMessage(
         id: 'hist-m5',
         role: 'assistant',
         content: '你好，我有什么可以帮你的？',
+        timestamp: yesterday.add(const Duration(hours: 9)),
       ),
     ];
   }