Initial commit

lib/providers/chat_provider.dart

@@ -0,0 +1,89 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import '../models/message.dart';
+import '../services/api_service.dart';
+
+class ChatState {
+  final List<ChatMessage> messages;
+  final bool isLoading;
+  final String? error;
+
+  const ChatState({this.messages = const [], this.isLoading = false, this.error});
+
+  ChatState copyWith({List<ChatMessage>? messages, bool? isLoading, String? error}) {
+    return ChatState(
+      messages: messages ?? this.messages,
+      isLoading: isLoading ?? this.isLoading,
+      error: error,
+    );
+  }
+}
+
+class ChatNotifier extends StateNotifier<ChatState> {
+  ChatNotifier() : super(const ChatState()) {
+    _loadHistory();
+  }
+
+  Future<void> _loadHistory() async {
+    try {
+      final messages = await apiService.getChatHistory();
+      state = state.copyWith(messages: messages);
+    } catch (_) {}
+  }
+
+  Future<void> sendMessage(String content) async {
+    if (content.trim().isEmpty) return;
+
+    final userMessage = ChatMessage(
+      id: 'msg_user_${DateTime.now().millisecondsSinceEpoch}',
+      content: content.trim(),
+      type: MessageType.text,
+      sender: MessageSender.user,
+      timestamp: DateTime.now(),
+    );
+
+    state = state.copyWith(
+      messages: [...state.messages, userMessage],
+      isLoading: true,
+    );
+
+    final loadingMessage = ChatMessage(
+      id: 'msg_loading_${DateTime.now().millisecondsSinceEpoch}',
+      content: '',
+      type: MessageType.loading,
+      sender: MessageSender.ai,
+      timestamp: DateTime.now(),
+    );
+
+    state = state.copyWith(
+      messages: [...state.messages, loadingMessage],
+    );
+
+    try {
+      final response = await apiService.sendMessage(content);
+      final updatedMessages = [...state.messages];
+      updatedMessages.removeLast();
+      updatedMessages.add(response);
+      state = state.copyWith(messages: updatedMessages, isLoading: false);
+    } catch (e) {
+      final updatedMessages = [...state.messages];
+      updatedMessages.removeLast();
+      updatedMessages.add(ChatMessage(
+        id: 'msg_err_${DateTime.now().millisecondsSinceEpoch}',
+        content: '抱歉，消息发送失败，请稍后重试。',
+        type: MessageType.text,
+        sender: MessageSender.ai,
+        timestamp: DateTime.now(),
+      ));
+      state = state.copyWith(messages: updatedMessages, isLoading: false, error: e.toString());
+    }
+  }
+
+  void clearMessages() {
+    state = const ChatState();
+    _loadHistory();
+  }
+}
+
+final chatProvider = StateNotifierProvider<ChatNotifier, ChatState>((ref) {
+  return ChatNotifier();
+});