AI 接入 V0.1

2026-09-23 17:23:59 +08:00
parent a83cda63f5
commit 34bc2e04b0
9 changed files with 1018 additions and 116 deletions
@@ -0,0 +1,189 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+import '../api/ai_api.dart';
+import '../core/network/api_exception.dart';
+import '../models/ai.dart';
+
+/// 后端 AI 是否配好了（没配 key 时 App 显示提示，而不是让用户白问一句）
+final aiStatusProvider = FutureProvider.autoDispose<bool>((ref) {
+  return ref.watch(aiApiProvider).status();
+});
+
+/// 会话列表
+final chatSessionsProvider = FutureProvider.autoDispose<List<ChatSessionItem>>((ref) {
+  return ref.watch(aiApiProvider).sessions();
+});
+
+/// 助手页状态
+class AssistantState {
+  /// null = 新对话（还没落库，第一条消息发出去时后端才建）
+  final int? sessionId;
+
+  final List<ChatBubble> bubbles;
+
+  /// 正在生成回答
+  final bool streaming;
+
+  /// 正在调用哪个工具（null = 没在查东西）
+  final String? activeTool;
+
+  final String? error;
+
+  /// 正在拉历史消息
+  final bool loadingHistory;
+
+  const AssistantState({
+    this.sessionId,
+    this.bubbles = const [],
+    this.streaming = false,
+    this.activeTool,
+    this.error,
+    this.loadingHistory = false,
+  });
+
+  /// 真的一句都没有（不是加载中、也不是出错）
+  bool get isEmpty => bubbles.isEmpty && !loadingHistory && error == null;
+
+  AssistantState copyWith({
+    Object? sessionId = _sentinel,
+    List<ChatBubble>? bubbles,
+    bool? streaming,
+    Object? activeTool = _sentinel,
+    Object? error = _sentinel,
+    bool? loadingHistory,
+  }) {
+    return AssistantState(
+      sessionId: sessionId == _sentinel ? this.sessionId : sessionId as int?,
+      bubbles: bubbles ?? this.bubbles,
+      streaming: streaming ?? this.streaming,
+      activeTool: activeTool == _sentinel ? this.activeTool : activeTool as String?,
+      error: error == _sentinel ? this.error : error as String?,
+      loadingHistory: loadingHistory ?? this.loadingHistory,
+    );
+  }
+
+  static const _sentinel = Object();
+}
+
+class AssistantNotifier extends Notifier<AssistantState> {
+  @override
+  AssistantState build() => const AssistantState();
+
+  /// 新对话：清空界面，但**不清 sessionId 为 null 之前的会话**（后端那边还在，能从历史里翻出来）
+  void newChat() {
+    state = const AssistantState();
+  }
+
+  void clearError() {
+    state = state.copyWith(error: null);
+  }
+
+  /// 打开历史会话
+  Future<void> openSession(int sessionId) async {
+    state = AssistantState(sessionId: sessionId, loadingHistory: true);
+    try {
+      final items = await ref.read(aiApiProvider).messages(sessionId);
+      if (!ref.mounted) return;
+      state = AssistantState(
+        sessionId: sessionId,
+        bubbles: items.map(ChatBubble.fromItem).toList(),
+      );
+    } catch (e) {
+      if (!ref.mounted) return;
+      state = AssistantState(
+        sessionId: sessionId,
+        error: e is ApiException ? e.message : '消息加载失败',
+      );
+    }
+  }
+
+  /// 发一条消息并接收流式回答
+  Future<void> send(String text) async {
+    final trimmed = text.trim();
+    if (trimmed.isEmpty || state.streaming) return;
+
+    state = state.copyWith(
+      // 先乐观地把用户气泡和「空的、正在生成」的回答气泡放上去
+      bubbles: [
+        ...state.bubbles,
+        ChatBubble.user(trimmed),
+        const ChatBubble.assistant('', streaming: true),
+      ],
+      streaming: true,
+      error: null,
+      activeTool: null,
+    );
+
+    var failed = false;
+    // 收到 done 说明回答已经完整了，之后连接怎么断都不该算失败 ——
+    // SSE 的收尾阶段出错（服务端异步派发、代理截断）很常见，
+    // 弹个红条出来只会让人以为回答没拿到。
+    var sawDone = false;
+    try {
+      await for (final event in ref
+          .read(aiApiProvider)
+          .chat(sessionId: state.sessionId, content: trimmed)) {
+        if (!ref.mounted) return;
+
+        switch (event.type) {
+          case AiEventType.delta:
+            _appendDelta(event.content ?? '');
+          case AiEventType.tool:
+            state = state.copyWith(activeTool: event.toolName);
+          case AiEventType.done:
+            // 新会话时后端在这一刻才把 ID 告诉我们，必须记下来，
+            // 否则下一条消息又会开一个新会话
+            sawDone = true;
+            state = state.copyWith(sessionId: event.sessionId);
+          case AiEventType.error:
+            if (!sawDone) {
+              failed = true;
+              state = state.copyWith(error: event.message);
+            }
+        }
+      }
+    } catch (e) {
+      if (!sawDone) {
+        failed = true;
+        state = state.copyWith(error: e is ApiException ? e.message : 'AI 连接中断');
+      }
+    }
+
+    _finish(failed: failed);
+  }
+
+  void _appendDelta(String delta) {
+    if (delta.isEmpty) return;
+    final bubbles = [...state.bubbles];
+    if (bubbles.isEmpty) return;
+
+    final last = bubbles.last;
+    bubbles[bubbles.length - 1] = last.copyWith(content: last.content + delta);
+    // 有文字出来了，说明工具已经查完
+    state = state.copyWith(bubbles: bubbles, activeTool: null);
+  }
+
+  void _finish({required bool failed}) {
+    var bubbles = [...state.bubbles];
+
+    if (failed) {
+      // 一条字都没生成出来时，把那个空气泡去掉，只留错误提示
+      if (bubbles.isNotEmpty && !bubbles.last.isUser && bubbles.last.content.isEmpty) {
+        bubbles.removeLast();
+      }
+    } else if (bubbles.isNotEmpty && bubbles.last.streaming) {
+      bubbles[bubbles.length - 1] = bubbles.last.copyWith(streaming: false);
+    }
+
+    state = state.copyWith(bubbles: bubbles, streaming: false, activeTool: null);
+
+    if (!failed) {
+      // 新会话要出现在列表里、老会话的标题/时间要更新
+      ref.invalidate(chatSessionsProvider);
+    }
+  }
+}
+
+/// 不加 autoDispose：切到别的 Tab 再回来，对话还在
+final assistantProvider =
+    NotifierProvider<AssistantNotifier, AssistantState>(AssistantNotifier.new);