优化

client/flutter/lib/providers/chat_provider.dart

@@ -0,0 +1,197 @@
+import 'package:flutter/material.dart';
+import 'package:sales_chat/models/group.dart';
+import 'package:sales_chat/models/message.dart';
+import 'package:sales_chat/services/api_service.dart';
+
+class ChatProvider with ChangeNotifier {
+  final ApiService _apiService;
+
+  List<Group> _groups = [];
+  Map<String, List<Message>> _messagesByConverse = {};
+  Group? _currentGroup;
+  bool _isLoading = false;
+  bool _isLoadingMessages = false;
+  String? _error;
+
+  ChatProvider(this._apiService);
+
+  List<Group> get groups => _groups;
+  Group? get currentGroup => _currentGroup;
+  bool get isLoading => _isLoading;
+  bool get isLoadingMessages => _isLoadingMessages;
+  String? get error => _error;
+
+  List<Message> get currentMessages {
+    if (_currentGroup == null) return [];
+    // 使用第一个文本面板的 ID 作为 converseId
+    final converseId = _currentGroup!.firstTextPanel?.id ?? _currentGroup!.id;
+    return _messagesByConverse[converseId] ?? [];
+  }
+
+  /// 获取群组的 converseId（第一个文本面板，或以群组 ID 作为备选）
+  String _getConverseIdForGroup(Group group) {
+    return group.firstTextPanel?.id ?? group.id;
+  }
+
+  Future<void> loadGroups() async {
+    _isLoading = true;
+    _error = null;
+    notifyListeners();
+
+    try {
+      _groups = await _apiService.getGroups();
+      _isLoading = false;
+      notifyListeners();
+    } catch (e) {
+      _error = 'Failed to load groups';
+      _isLoading = false;
+      notifyListeners();
+    }
+  }
+
+  void selectGroup(Group group) {
+    _currentGroup = group;
+    notifyListeners();
+
+    final converseId = _getConverseIdForGroup(group);
+    if (_messagesByConverse[converseId] == null) {
+      loadMessages(converseId);
+    }
+  }
+
+  void deselectGroup() {
+    _currentGroup = null;
+    notifyListeners();
+  }
+
+  Future<void> loadMessages(String converseId, {bool refresh = false}) async {
+    if (_isLoadingMessages) return;
+
+    _isLoadingMessages = true;
+    notifyListeners();
+
+    try {
+      final messages = await _apiService.getMessages(
+        converseId,
+        limit: 50,
+        before: refresh ? null : (_messagesByConverse[converseId]?.first.id),
+      );
+
+      if (refresh) {
+        _messagesByConverse[converseId] = messages;
+      } else {
+        _messagesByConverse[converseId] = [
+          ...messages,
+          ...(_messagesByConverse[converseId] ?? [])
+        ];
+      }
+
+      _isLoadingMessages = false;
+      notifyListeners();
+    } catch (e) {
+      _error = 'Failed to load messages';
+      _isLoadingMessages = false;
+      notifyListeners();
+    }
+  }
+
+  Future<void> sendMessage(String content) async {
+    if (_currentGroup == null || content.isEmpty) return;
+
+    final converseId = _getConverseIdForGroup(_currentGroup!);
+    final groupId = _currentGroup!.id;
+
+    try {
+      final message = await _apiService.sendMessage(
+        converseId,
+        content,
+        groupId: groupId,
+      );
+
+      _messagesByConverse[converseId] = [
+        ...(_messagesByConverse[converseId] ?? []),
+        message,
+      ];
+      notifyListeners();
+    } catch (e) {
+      _error = 'Failed to send message';
+      notifyListeners();
+    }
+  }
+
+  /// 撤回消息
+  Future<bool> recallMessage(String messageId) async {
+    try {
+      await _apiService.recallMessage(messageId);
+
+      // 更新本地消息列表
+      if (_currentGroup != null) {
+        final converseId = _getConverseIdForGroup(_currentGroup!);
+        final messages = _messagesByConverse[converseId];
+        if (messages != null) {
+          final idx = messages.indexWhere((m) => m.id == messageId);
+          if (idx != -1) {
+            // 标记为已撤回而非删除
+            final old = messages[idx];
+            messages[idx] = Message(
+              id: old.id,
+              content: 'Message recalled',
+              author: old.author,
+              groupId: old.groupId,
+              converseId: old.converseId,
+              hasRecall: true,
+              meta: old.meta,
+              createdAt: old.createdAt,
+              updatedAt: old.updatedAt,
+            );
+            notifyListeners();
+          }
+        }
+      }
+
+      return true;
+    } catch (e) {
+      _error = 'Failed to recall message: $e';
+      notifyListeners();
+      return false;
+    }
+  }
+
+  /// 删除消息（管理员）
+  Future<bool> deleteMessage(String messageId) async {
+    try {
+      await _apiService.deleteMessage(messageId);
+
+      // 从本地消息列表中移除
+      if (_currentGroup != null) {
+        final converseId = _getConverseIdForGroup(_currentGroup!);
+        final messages = _messagesByConverse[converseId];
+        if (messages != null) {
+          messages.removeWhere((m) => m.id == messageId);
+          notifyListeners();
+        }
+      }
+
+      return true;
+    } catch (e) {
+      _error = 'Failed to delete message: $e';
+      notifyListeners();
+      return false;
+    }
+  }
+
+  /// 添加通过 socket.io 接收的消息
+  void addMessage(Message message) {
+    final converseId = message.converseId;
+    _messagesByConverse[converseId] = [
+      ...(_messagesByConverse[converseId] ?? []),
+      message,
+    ];
+    notifyListeners();
+  }
+
+  void clearError() {
+    _error = null;
+    notifyListeners();
+  }
+}