feat: 角色卡 demo

wei_ai_app/lib/core/services/chat_service.dart

@@ -0,0 +1,183 @@
+import 'dart:async';
+import 'dart:convert';
+import 'package:flutter/foundation.dart';
+import 'package:http/http.dart' as http;
+import '../models/chat_message_model.dart';
+import '../models/llm_config_model.dart';
+import '../models/character_model.dart';
+import '../repositories/llm_config_repository.dart';
+
+/// AI 聊天服务
+/// 
+/// 负责调用 LLM API 进行对话
+class ChatService {
+  ChatService._();
+
+  /// 发送消息并获取 AI 回复
+  /// 
+  /// [character] 当前对话的角色
+  /// [messages] 历史消息列表
+  /// [userMessage] 用户新发送的消息
+  /// [onStream] 流式输出回调（每次收到新内容时调用）
+  static Future<String> sendMessage({
+    required CharacterModel character,
+    required List<ChatMessage> messages,
+    required String userMessage,
+    Function(String)? onStream,
+  }) async {
+    // 获取 LLM 配置
+    final config = await LlmConfigRepository.getActiveConfig();
+    if (config == null) {
+      throw Exception('LLM 配置未找到，请先配置 API Key');
+    }
+
+    // 构建消息列表
+    final apiMessages = <Map<String, String>>[];
+
+    // 1. System prompt（角色人设）
+    final systemPrompt = character.aiSystemPrompt ?? 
+        '你是 ${character.name}，${character.tagline ?? "一个AI角色"}。${character.description ?? ""}';
+    apiMessages.add({'role': 'system', 'content': systemPrompt});
+
+    // 2. 历史消息（最多保留最近 20 条）
+    final recentMessages = messages.length > 20 
+        ? messages.sublist(messages.length - 20) 
+        : messages;
+    for (final msg in recentMessages) {
+      if (msg.role != 'system') {
+        apiMessages.add(msg.toApiFormat());
+      }
+    }
+
+    // 3. 新用户消息
+    apiMessages.add({'role': 'user', 'content': userMessage});
+
+    debugPrint('📤 发送到 LLM: ${apiMessages.length} 条消息');
+
+    // 判断是否使用流式输出
+    if (config.stream && onStream != null) {
+      return _sendStreamRequest(config, apiMessages, onStream);
+    } else {
+      return _sendNormalRequest(config, apiMessages);
+    }
+  }
+
+  /// 普通请求（非流式）
+  static Future<String> _sendNormalRequest(
+    LlmConfigModel config,
+    List<Map<String, String>> messages,
+  ) async {
+    try {
+      final response = await http.post(
+        Uri.parse(config.chatCompletionsUrl),
+        headers: {
+          'Content-Type': 'application/json',
+          'Authorization': 'Bearer ${config.apiKey}',
+        },
+        body: jsonEncode({
+          'model': config.model,
+          'messages': messages,
+          'temperature': config.temperature,
+          'max_tokens': config.maxTokens,
+          'stream': false,
+        }),
+      );
+
+      if (response.statusCode != 200) {
+        debugPrint('❌ LLM API 错误: ${response.statusCode} ${response.body}');
+        throw Exception('API 请求失败: ${response.statusCode}');
+      }
+
+      final data = jsonDecode(response.body);
+      final content = data['choices'][0]['message']['content'] as String;
+      debugPrint('📥 收到回复: ${content.substring(0, content.length.clamp(0, 50))}...');
+      return content;
+    } catch (e) {
+      debugPrint('❌ LLM 请求失败: $e');
+      rethrow;
+    }
+  }
+
+  /// 流式请求
+  static Future<String> _sendStreamRequest(
+    LlmConfigModel config,
+    List<Map<String, String>> messages,
+    Function(String) onStream,
+  ) async {
+    try {
+      final client = http.Client();
+      final request = http.Request('POST', Uri.parse(config.chatCompletionsUrl));
+      
+      request.headers.addAll({
+        'Content-Type': 'application/json',
+        'Authorization': 'Bearer ${config.apiKey}',
+        'Accept': 'text/event-stream',
+      });
+
+      request.body = jsonEncode({
+        'model': config.model,
+        'messages': messages,
+        'temperature': config.temperature,
+        'max_tokens': config.maxTokens,
+        'stream': true,
+      });
+
+      final response = await client.send(request);
+
+      if (response.statusCode != 200) {
+        final body = await response.stream.bytesToString();
+        debugPrint('❌ LLM API 错误: ${response.statusCode} $body');
+        throw Exception('API 请求失败: ${response.statusCode}');
+      }
+
+      final completer = Completer<String>();
+      final buffer = StringBuffer();
+
+      response.stream
+          .transform(utf8.decoder)
+          .transform(const LineSplitter())
+          .listen(
+        (line) {
+          if (line.startsWith('data: ')) {
+            final data = line.substring(6);
+            if (data == '[DONE]') {
+              return;
+            }
+            try {
+              final json = jsonDecode(data);
+              final delta = json['choices']?[0]?['delta']?['content'];
+              if (delta != null && delta is String) {
+                buffer.write(delta);
+                onStream(buffer.toString());
+              }
+            } catch (e) {
+              // 忽略解析错误
+            }
+          }
+        },
+        onDone: () {
+          client.close();
+          final result = buffer.toString();
+          debugPrint('📥 流式回复完成: ${result.length} 字符');
+          completer.complete(result);
+        },
+        onError: (e) {
+          client.close();
+          debugPrint('❌ 流式请求错误: $e');
+          completer.completeError(e);
+        },
+      );
+
+      return completer.future;
+    } catch (e) {
+      debugPrint('❌ LLM 流式请求失败: $e');
+      rethrow;
+    }
+  }
+
+  /// 获取角色的问候语
+  static String getGreeting(CharacterModel character) {
+    return character.aiGreeting ?? 
+        '你好，我是 ${character.name}。有什么我可以帮你的吗？';
+  }
+}

wei_ai_app/lib/core/services/chat_storage_service.dart

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+import 'dart:convert';
+import 'package:flutter/foundation.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+import '../models/chat_message_model.dart';
+
+/// 本地聊天存储服务
+/// 
+/// 使用 SharedPreferences 存储聊天记录
+class ChatStorageService {
+  ChatStorageService._();
+
+  static const String _keyPrefix = 'chat_session_';
+
+  /// 获取聊天会话
+  static Future<ChatSession> getSession(String characterId) async {
+    try {
+      final prefs = await SharedPreferences.getInstance();
+      final key = '$_keyPrefix$characterId';
+      final data = prefs.getString(key);
+      
+      if (data == null) {
+        return ChatSession.empty(characterId);
+      }
+
+      return ChatSession.fromJson(jsonDecode(data));
+    } catch (e) {
+      debugPrint('❌ 读取聊天记录失败: $e');
+      return ChatSession.empty(characterId);
+    }
+  }
+
+  /// 保存聊天会话
+  static Future<void> saveSession(ChatSession session) async {
+    try {
+      final prefs = await SharedPreferences.getInstance();
+      final key = '$_keyPrefix${session.characterId}';
+      await prefs.setString(key, jsonEncode(session.toJson()));
+      debugPrint('✅ 聊天记录已保存 (${session.messages.length} 条消息)');
+    } catch (e) {
+      debugPrint('❌ 保存聊天记录失败: $e');
+    }
+  }
+
+  /// 添加消息到会话
+  static Future<ChatSession> addMessage(String characterId, ChatMessage message) async {
+    final session = await getSession(characterId);
+    final newSession = session.addMessage(message);
+    await saveSession(newSession);
+    return newSession;
+  }
+
+  /// 清除角色的聊天记录
+  static Future<void> clearSession(String characterId) async {
+    try {
+      final prefs = await SharedPreferences.getInstance();
+      final key = '$_keyPrefix$characterId';
+      await prefs.remove(key);
+      debugPrint('✅ 聊天记录已清除');
+    } catch (e) {
+      debugPrint('❌ 清除聊天记录失败: $e');
+    }
+  }
+
+  /// 获取所有聊天会话的角色 ID 列表
+  static Future<List<String>> getAllSessionIds() async {
+    try {
+      final prefs = await SharedPreferences.getInstance();
+      final keys = prefs.getKeys();
+      return keys
+          .where((k) => k.startsWith(_keyPrefix))
+          .map((k) => k.substring(_keyPrefix.length))
+          .toList();
+    } catch (e) {
+      debugPrint('❌ 获取会话列表失败: $e');
+      return [];
+    }
+  }
+}

wei_ai_app/lib/core/services/services.dart

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+/// Core Services 导出
+library services;
+
+export 'supabase_service.dart';
+export 'chat_service.dart';
+export 'chat_storage_service.dart';

wei_ai_app/lib/core/services/supabase_service.dart

@@ -0,0 +1,60 @@
+import 'package:flutter/foundation.dart';
+import 'package:supabase_flutter/supabase_flutter.dart';
+import '../config/supabase_config.dart';
+
+/// Supabase 服务
+/// 
+/// 负责初始化和管理 Supabase 客户端
+class SupabaseService {
+  SupabaseService._();
+
+  static bool _initialized = false;
+
+  /// 初始化 Supabase
+  /// 
+  /// 应该在 main() 函数中调用，确保在 runApp 之前完成
+  static Future<void> initialize() async {
+    if (_initialized) {
+      debugPrint('⚠️ Supabase 已经初始化过了');
+      return;
+    }
+
+    try {
+      await Supabase.initialize(
+        url: SupabaseConfig.url,
+        anonKey: SupabaseConfig.anonKey,
+        debug: SupabaseConfig.debug,
+      );
+      _initialized = true;
+      debugPrint('✅ Supabase 初始化成功');
+      debugPrint('   URL: ${SupabaseConfig.url}');
+    } catch (e) {
+      debugPrint('❌ Supabase 初始化失败: $e');
+      rethrow;
+    }
+  }
+
+  /// 获取 Supabase 客户端实例
+  static SupabaseClient get client => Supabase.instance.client;
+
+  /// 获取当前登录用户
+  static User? get currentUser => client.auth.currentUser;
+
+  /// 检查用户是否已登录
+  static bool get isLoggedIn => currentUser != null;
+
+  /// 获取 Auth 实例
+  static GoTrueClient get auth => client.auth;
+
+  /// 获取数据库实例
+  static SupabaseQueryBuilder from(String table) => client.from(table);
+
+  /// 获取存储实例
+  static SupabaseStorageClient get storage => client.storage;
+
+  /// 获取 Realtime 实例
+  static RealtimeClient get realtime => client.realtime;
+
+  /// 获取 Functions 实例
+  static FunctionsClient get functions => client.functions;
+}