dual check v0.1

client/lib/modules/dual_check/api.dart

@@ -0,0 +1,253 @@
+// DualCheck API 封装
+// 后端统一响应格式：{code:0, message, data}
+// WebSocket 消息格式：{type, data, error}
+import 'package:dio/dio.dart';
+import 'package:flutter/foundation.dart';
+
+/// 后端地址
+const String _baseUrl = kIsWeb
+    ? 'http://localhost:8080'
+    : 'http://127.0.0.1:8080';
+
+/// WebSocket 地址
+const String _wsBaseUrl =
+    kIsWeb ? 'ws://localhost:8080' : 'ws://127.0.0.1:8080';
+
+class DualCheckApi {
+  DualCheckApi()
+      : _dio = Dio(BaseOptions(
+          baseUrl: _baseUrl,
+          connectTimeout: const Duration(seconds: 10),
+          receiveTimeout: const Duration(seconds: 10),
+        )) {
+    _dio.interceptors.add(InterceptorsWrapper(
+      onResponse: (response, handler) {
+        final data = response.data;
+        if (data is Map<String, dynamic> && data['code'] != 0) {
+          handler.reject(DioException(
+            requestOptions: response.requestOptions,
+            response: response,
+            type: DioExceptionType.badResponse,
+            error: _BizError(data['code'] as int, data['message'] as String),
+          ));
+          return;
+        }
+        handler.next(response);
+      },
+    ));
+  }
+
+  final Dio _dio;
+
+  // ── Create ──
+
+  Future<CreateResp> createSession({required String nickname}) async {
+    final res = await _dio.post<Map<String, dynamic>>(
+      '/api/v1/dual-check/create',
+      data: {'nickname': nickname},
+    );
+    final d = res.data!['data'] as Map<String, dynamic>;
+    return CreateResp(
+      sessionId: d['session_id'] as String,
+      nickname: d['nickname'] as String,
+      ttl: d['ttl_seconds'] as int,
+    );
+  }
+
+  // ── Submit ──
+
+  Future<SubmitResp> submit({
+    required String sessionId,
+    required String nickname,
+    required String role, // "initiator" | "participant"
+    required String text,
+  }) async {
+    final res = await _dio.post<Map<String, dynamic>>(
+      '/api/v1/dual-check/submit',
+      data: {
+        'session_id': sessionId,
+        'nickname': nickname,
+        'role': role,
+        'text': text,
+      },
+    );
+    final d = res.data!['data'] as Map<String, dynamic>;
+    return SubmitResp(
+      submitted: d['submitted'] as bool,
+      initiatorReady: d['initiator_ready'] as bool,
+      match: d['match'] as bool?,
+    );
+  }
+
+  // ── CheckSession ──
+
+  Future<CheckResp> checkSession(String sessionId) async {
+    final res = await _dio.get<Map<String, dynamic>>(
+      '/api/v1/dual-check/check/$sessionId',
+    );
+    final d = res.data!['data'] as Map<String, dynamic>;
+    return CheckResp(
+      exists: d['exists'] as bool,
+      initiatorReady: d['initiator_ready'] as bool,
+      participantCount: d['participant_count'] as int,
+      ttlSeconds: d['ttl_seconds'] as int,
+    );
+  }
+
+  // ── GetSession 全量快照 ──
+
+  Future<SessionResp> getSession(String sessionId) async {
+    final res = await _dio.get<Map<String, dynamic>>(
+      '/api/v1/dual-check/session/$sessionId',
+    );
+    return parseSession(res.data!['data'] as Map<String, dynamic>);
+  }
+
+  // ── SetResubmit 发起方切换"允许参与者重新提交" ──
+
+  Future<SessionResp> setResubmit(String sessionId, {required bool allow}) async {
+    final res = await _dio.post<Map<String, dynamic>>(
+      '/api/v1/dual-check/session/$sessionId/resubmit',
+      data: {'allow': allow},
+    );
+    return parseSession(res.data!['data'] as Map<String, dynamic>);
+  }
+
+  // ── EndSession 发起方主动结束会话 ──
+
+  Future<void> endSession(String sessionId) async {
+    await _dio.post('/api/v1/dual-check/session/$sessionId/end');
+  }
+
+  static SessionResp parseSession(Map<String, dynamic> d) {
+    final parts = (d['participants'] as List)
+        .map((p) => ParticipantResp.fromMap(p as Map<String, dynamic>))
+        .toList();
+    return SessionResp(
+      sessionId: d['session_id'] as String,
+      initiatorNickname: (d['initiator_nickname'] ?? '') as String,
+      initiatorReady: d['initiator_ready'] as bool,
+      allowResubmit: (d['allow_resubmit'] as bool?) ?? false,
+      participants: parts,
+      ttlSeconds: d['ttl_seconds'] as int,
+    );
+  }
+
+  // ── WS URL ──
+
+  String wsUrl({
+    required String sessionId,
+    required String role,
+    required String nickname,
+  }) {
+    return '$_wsBaseUrl/api/v1/dual-check/ws'
+        '?session_id=${Uri.encodeQueryComponent(sessionId)}'
+        '&role=$role'
+        '&nickname=${Uri.encodeQueryComponent(nickname)}';
+  }
+}
+
+// ── 数据模型 ──
+
+class CreateResp {
+  final String sessionId;
+  final String nickname;
+  final int ttl;
+  CreateResp({required this.sessionId, required this.nickname, required this.ttl});
+}
+
+class SubmitResp {
+  final bool submitted;
+  final bool initiatorReady;
+  final bool? match;
+  SubmitResp({required this.submitted, required this.initiatorReady, this.match});
+}
+
+class CheckResp {
+  final bool exists;
+  final bool initiatorReady;
+  final int participantCount;
+  final int ttlSeconds;
+  CheckResp({
+    required this.exists,
+    required this.initiatorReady,
+    required this.participantCount,
+    required this.ttlSeconds,
+  });
+}
+
+class ParticipantResp {
+  final String nickname;
+  final bool joined;
+  final bool submitted;
+  final bool? match;
+  ParticipantResp({
+    required this.nickname,
+    required this.joined,
+    required this.submitted,
+    this.match,
+  });
+  factory ParticipantResp.fromMap(Map<String, dynamic> m) {
+    return ParticipantResp(
+      nickname: m['nickname'] as String,
+      joined: m['joined'] as bool? ?? true,
+      submitted: m['submitted'] as bool,
+      match: m['match'] as bool?,
+    );
+  }
+}
+
+class SessionResp {
+  final String sessionId;
+  final String initiatorNickname;
+  final bool initiatorReady;
+  final bool allowResubmit;
+  final List<ParticipantResp> participants;
+  final int ttlSeconds;
+  SessionResp({
+    required this.sessionId,
+    required this.initiatorNickname,
+    required this.initiatorReady,
+    required this.allowResubmit,
+    required this.participants,
+    required this.ttlSeconds,
+  });
+}
+
+// ── WS 消息类型 ──
+
+class WSMessage {
+  final String type;
+  final Map<String, dynamic> data;
+  final String? error;
+
+  WSMessage({required this.type, required this.data, this.error});
+
+  factory WSMessage.fromJson(Map<String, dynamic> json) {
+    return WSMessage(
+      type: json['type'] as String,
+      data: (json['data'] as Map<String, dynamic>?) ?? const {},
+      error: json['error'] as String?,
+    );
+  }
+}
+
+// ── 业务错误处理 ──
+
+class _BizError implements Exception {
+  _BizError(this.code, this.message);
+  final int code;
+  final String message;
+  @override
+  String toString() => '[biz:$code] $message';
+}
+
+bool isBizError(DioException e) => e.error is _BizError;
+int? bizErrorCode(DioException e) {
+  final err = e.error;
+  return err is _BizError ? err.code : null;
+}
+String bizErrorMessage(DioException e) {
+  final err = e.error;
+  return err is _BizError ? err.message : (e.message ?? '请求失败');
+}

client/lib/modules/dual_check/dual_check.dart

@@ -1,4 +1,18 @@
-import 'package:flutter/cupertino.dart';
+// DualCheck 主页面（多参与者版）
+// 一个发起方（initiator）提交标准答案，多个参与者（participant）各自提交文本
+// 通过 WebSocket 实时同步参与者列表 + 提交状态 + match 结果
+import 'dart:async';
+import 'dart:convert';
+
+import 'package:dio/dio.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:web_socket_channel/web_socket_channel.dart';
+
+import 'api.dart';
+import 'nickname_service.dart';
+
+enum _RoleSelect { initiator, participant }
 
 class DualCheck extends StatefulWidget {
   const DualCheck({super.key});
@@ -8,8 +22,963 @@ class DualCheck extends StatefulWidget {
 }
 
 class _DualCheckState extends State<DualCheck> {
+  final _api = DualCheckApi();
+  final _nickService = NicknameService.instance;
+  final _textCtrl = TextEditingController();
+
+  // ── 会话状态 ──
+  String? _sessionId;
+  late String _nickname = '用户';
+  late _RoleSelect _myRole = _RoleSelect.initiator;
+  SessionResp? _session; // 当前会话全量状态（发起方视图）
+
+  // ── WS ──
+  WebSocketChannel? _ws;
+  StreamSubscription? _wsSub;
+
+  // ── UI 状态 ──
+  bool _isLoading = false;
+  String? _errorMsg;
+
+  @override
+  void initState() {
+    super.initState();
+    _loadNickname();
+  }
+
+  Future<void> _loadNickname() async {
+    final n = await _nickService.nickname;
+    if (!mounted) return;
+    setState(() => _nickname = n);
+  }
+
+  @override
+  void dispose() {
+    _wsSub?.cancel();
+    _ws?.sink.close();
+    _textCtrl.dispose();
+    super.dispose();
+  }
+
+  // ── 发起方：创建会话 ──
+  Future<void> _createSession() async {
+    setState(() => _isLoading = true);
+    try {
+      final resp = await _api.createSession(nickname: _nickname);
+      setState(() {
+        _sessionId = resp.sessionId;
+        _myRole = _RoleSelect.initiator;
+      });
+      // WS 连接（发起方不需要 join，直接连接）
+      _connectWs();
+    } on DioException catch (e) {
+      setState(() => _errorMsg = isBizError(e) ? bizErrorMessage(e) : '创建失败');
+    } catch (e) {
+      setState(() => _errorMsg = '创建失败：$e');
+    } finally {
+      setState(() => _isLoading = false);
+    }
+  }
+
+  // ── 参与方：输入会话码加入（对话框内校验） ──
+  void _showJoinDialog() {
+    final ctrl = TextEditingController();
+    bool isChecking = false;
+    String? err;
+
+    showDialog(
+      context: context,
+      builder: (ctx) => StatefulBuilder(
+        builder: (ctx, set) => AlertDialog(
+          title: const Text('输入会话码加入'),
+          content: Column(
+            mainAxisSize: MainAxisSize.min,
+            children: [
+              TextField(
+                controller: ctrl,
+                enabled: !isChecking,
+                decoration: const InputDecoration(
+                  hintText: '粘贴或输入会话码',
+                  border: OutlineInputBorder(),
+                ),
+              ),
+              if (err != null)
+                Padding(
+                  padding: const EdgeInsets.only(top: 10),
+                  child: Text(err!,
+                      style: const TextStyle(color: Colors.red, fontSize: 13)),
+                ),
+            ],
+          ),
+          actions: [
+            TextButton(
+              onPressed: isChecking ? null : () => Navigator.pop(ctx),
+              child: const Text('取消'),
+            ),
+            FilledButton(
+              onPressed: isChecking
+                  ? null
+                  : () async {
+                      final sid = ctrl.text.trim();
+                      if (sid.isEmpty) {
+                        set(() => err = '请输入会话码');
+                        return;
+                      }
+                      set(() {
+                        isChecking = true;
+                        err = null;
+                      });
+                      try {
+                        await _api.checkSession(sid);
+                        if (!ctx.mounted) return;
+                        Navigator.pop(ctx);
+                        setState(() {
+                          _sessionId = sid;
+                          _myRole = _RoleSelect.participant;
+                        });
+                        _connectWs();
+                      } on DioException catch (e) {
+                        set(() {
+                          isChecking = false;
+                          err = isBizError(e)
+                              ? bizErrorMessage(e)
+                              : '无法连接服务器';
+                        });
+                      } catch (e) {
+                        set(() {
+                          isChecking = false;
+                          err = '校验失败：$e';
+                        });
+                      }
+                    },
+              child: isChecking
+                  ? const SizedBox(width: 16, height: 16,
+                      child: CircularProgressIndicator(strokeWidth: 2, color: Colors.white))
+                  : const Text('加入'),
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+
+  // ── WS 连接 ──
+  void _connectWs() {
+    final role = _myRole == _RoleSelect.initiator ? 'initiator' : 'participant';
+    final url = _api.wsUrl(
+      sessionId: _sessionId!,
+      role: role,
+      nickname: _nickname,
+    );
+    try {
+      _ws = WebSocketChannel.connect(Uri.parse(url));
+      _wsSub = _ws!.stream.listen(_onWsMessage, onError: (e) {
+        debugPrint('[DC] ws error: $e');
+      }, onDone: () {
+        debugPrint('[DC] ws closed');
+      });
+    } catch (e) {
+      debugPrint('[DC] ws connect fail: $e');
+    }
+  }
+
+  // ── WS 消息处理（事件驱动 UI） ──
+  void _onWsMessage(dynamic raw) {
+    try {
+      final msg = WSMessage.fromJson(
+          jsonDecode(raw as String) as Map<String, dynamic>);
+      switch (msg.type) {
+        case 'full_state':
+          final s = DualCheckApi.parseSession(msg.data);
+          setState(() => _session = s);
+        case 'participant_joined':
+          final nick = msg.data['nickname'] as String;
+          setState(() {
+            _session ??= SessionResp(
+                sessionId: _sessionId!,
+                initiatorNickname: '',
+                initiatorReady: false,
+                allowResubmit: false,
+                participants: [],
+                ttlSeconds: 0);
+            final list = List<ParticipantResp>.from(_session!.participants);
+            if (!list.any((p) => p.nickname == nick)) {
+              list.add(ParticipantResp(
+                  nickname: nick, joined: true, submitted: false));
+            }
+            _session = _session!.copyWith(participants: list);
+          });
+        case 'participant_left':
+          final nick = msg.data['nickname'] as String;
+          setState(() {
+            if (_session == null) return;
+            final list = List<ParticipantResp>.from(_session!.participants);
+            list.removeWhere((p) => p.nickname == nick);
+            _session = _session!.copyWith(participants: list);
+          });
+        case 'participant_submitted':
+          final nick = msg.data['nickname'] as String;
+          final submitData = msg.data['submit'] as Map<String, dynamic>;
+          setState(() {
+            if (_session == null) return;
+            final list = List<ParticipantResp>.from(_session!.participants);
+            final idx = list.indexWhere((p) => p.nickname == nick);
+            if (idx >= 0) {
+              list[idx] = list[idx].copyWith(
+                submitted: true,
+                match: submitData['match'] as bool?,
+              );
+            }
+            _session = _session!.copyWith(participants: list);
+          });
+        case 'initiator_ready':
+          setState(() {
+            if (_session != null) {
+              _session = _session!.copyWith(initiatorReady: true);
+            }
+          });
+        case 'resubmit_changed':
+          final allow = msg.data['allow'] as bool;
+          setState(() {
+            _session ??= SessionResp(
+                sessionId: _sessionId!,
+                initiatorNickname: '',
+                initiatorReady: false,
+                allowResubmit: false,
+                participants: [],
+                ttlSeconds: 0);
+            _session = _session!.copyWith(allowResubmit: allow);
+            if (allow) _errorMsg = null; // 开关打开时清掉上次"不能重提交"的报错
+          });
+        case 'session_ended':
+          // 只有参与者收到才弹窗——发起方自己就是结束者，不需要再提示自己
+          if (_myRole == _RoleSelect.participant) _showSessionEnded();
+      }
+    } catch (e) {
+      debugPrint('[DC] ws parse error: $e');
+    }
+  }
+
+  // ── 提交文本 ──
+  Future<void> _submit() async {
+    if (_sessionId == null) return;
+    final text = _textCtrl.text.trim();
+    if (text.isEmpty) {
+      setState(() => _errorMsg = '请输入内容后再提交');
+      return;
+    }
+    setState(() {
+      _isLoading = true;
+      _errorMsg = null; // 清除上次残留的报错
+    });
+    try {
+      final role = _myRole == _RoleSelect.initiator ? 'initiator' : 'participant';
+      final resp = await _api.submit(
+        sessionId: _sessionId!,
+        nickname: _nickname,
+        role: role,
+        text: text,
+      );
+      _textCtrl.clear();
+
+      // 参与者提交后立刻在本地更新会话状态
+      if (_myRole == _RoleSelect.participant) {
+        setState(() {
+          _session ??= SessionResp(
+              sessionId: _sessionId!,
+              initiatorNickname: '',
+              initiatorReady: false,
+              allowResubmit: false,
+              participants: [],
+              ttlSeconds: 0);
+          _session = _session!.copyWith(
+            initiatorReady: resp.initiatorReady,
+          );
+        });
+        // 如果 initiator 已提交，可以直接显示 match
+        if (resp.initiatorReady && resp.match != null) {
+          _showMyResult(resp.match!);
+        } else {
+          _showParticipantWaiting();
+        }
+      } else {
+        // 发起方提交后等 WS full_state 来刷新
+        if (!mounted) return;
+        ScaffoldMessenger.of(context).showSnackBar(
+          const SnackBar(content: Text('标准答案已提交，等待参与者...')),
+        );
+      }
+    } on DioException catch (e) {
+      final code = bizErrorCode(e);
+      String msg;
+      if (code == 1003) {
+        msg = '已提交过，等待发起方开启"允许重新提交"后再试';
+      } else {
+        msg = isBizError(e) ? bizErrorMessage(e) : '提交失败';
+      }
+      setState(() => _errorMsg = msg);
+    } catch (e) {
+      setState(() => _errorMsg = '提交失败：$e');
+    } finally {
+      setState(() => _isLoading = false);
+    }
+  }
+
+  // ── 重置 ──
+  void _reset() {
+    _wsSub?.cancel();
+    _ws?.sink.close();
+    _textCtrl.clear();
+    setState(() {
+      _ws = null;
+      _wsSub = null;
+      _sessionId = null;
+      _session = null;
+      _errorMsg = null;
+    });
+  }
+
+  // ── 发起方：主动结束会话（广播给所有人后退出） ──
+  Future<void> _confirmAndEndSession() async {
+    final confirmed = await showDialog<bool>(
+      context: context,
+      builder: (ctx) => AlertDialog(
+        icon: const Icon(Icons.warning_amber_rounded, size: 40, color: Colors.orange),
+        title: const Text('确定结束会话？'),
+        content: const Text('结束后所有参与者都会收到通知并自动退出，无法恢复。'),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.pop(ctx, false),
+            child: const Text('取消'),
+          ),
+          FilledButton(
+            onPressed: () => Navigator.pop(ctx, true),
+            style: FilledButton.styleFrom(backgroundColor: Colors.red),
+            child: const Text('确定结束'),
+          ),
+        ],
+      ),
+    );
+    if (confirmed == true && mounted) {
+      await _endSession();
+    }
+  }
+
+  Future<void> _endSession() async {
+    final sid = _sessionId;
+    if (sid == null) return;
+    try {
+      await _api.endSession(sid);
+    } catch (e) {
+      // 即使网络失败，后端也可能已成功，直接进入 reset
+      debugPrint('[DC] endSession api error (ignoring): $e');
+    }
+    if (!mounted) return;
+    _reset();
+  }
+
+  // ── 收到 session_ended WS 事件：弹窗 + 自动退出 ──
+  void _showSessionEnded() {
+    // 防重复弹窗（多次 session_ended / 重复 Build）
+    if (!mounted || _sessionId == null) return;
+    final sid = _sessionId!;
+    _reset();
+    if (!mounted) return;
+    showDialog(
+      context: context,
+      barrierDismissible: false,
+      builder: (ctx) => AlertDialog(
+        icon: const Icon(Icons.info_outline, size: 50, color: Colors.blue),
+        title: const Text('会话已结束'),
+        content: Text('会话 $sid 已由发起方主动结束，即将返回首页。'),
+        actions: [
+          FilledButton(
+            onPressed: () => Navigator.pop(ctx),
+            child: const Text('好的'),
+          ),
+        ],
+      ),
+    );
+  }
+
+  // ── 发起方：切换允许重提交开关 ──
+  Future<void> _toggleResubmit(bool value) async {
+    final sid = _sessionId;
+    if (sid == null) return;
+    setState(() {
+      _session = _session?.copyWith(allowResubmit: value);
+    });
+    try {
+      final sess = await _api.setResubmit(sid, allow: value);
+      if (!mounted) return;
+      setState(() => _session = sess);
+    } on DioException catch (e) {
+      // 失败回滚
+      if (!mounted) return;
+      setState(() {
+        _session = _session?.copyWith(allowResubmit: !value);
+      });
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(content: Text('操作失败：${bizErrorMessage(e)}')),
+      );
+    }
+  }
+
+  // ── 设置昵称对话框 ──
+  void _showNicknameDialog() {
+    final ctrl = TextEditingController(text: _nickname);
+    showDialog(
+      context: context,
+      builder: (ctx) => AlertDialog(
+        title: const Text('设置昵称'),
+        content: TextField(
+          controller: ctrl,
+          maxLength: 32,
+          decoration: const InputDecoration(
+            hintText: '1-32 字符',
+            border: OutlineInputBorder(),
+            counterText: '',
+          ),
+        ),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.pop(ctx),
+            child: const Text('取消'),
+          ),
+          FilledButton(
+            onPressed: () async {
+              final ok = await _nickService.setNickname(ctrl.text);
+              if (ok && ctx.mounted) Navigator.pop(ctx);
+              setState(() {
+                if (ok) _nickname = ctrl.text.trim();
+              });
+              if (ctx.mounted && !ok) {
+                ScaffoldMessenger.of(ctx).showSnackBar(
+                  const SnackBar(content: Text('昵称无效')),
+                );
+              }
+            },
+            child: const Text('保存'),
+          ),
+        ],
+      ),
+    );
+  }
+
+  // ── 参与者结果弹窗 ──
+  void _showMyResult(bool match) {
+    showDialog(
+      context: context,
+      builder: (ctx) => AlertDialog(
+        icon: Icon(match ? Icons.check_circle : Icons.cancel,
+            size: 60, color: match ? Colors.green : Colors.red),
+        title: Text(match ? '🎉 完全一致' : '❌ 不相同',
+            style: TextStyle(color: match ? Colors.green : Colors.red)),
+        content: Text('你的昵称：$_nickname'),
+        actions: [
+          TextButton(
+              onPressed: () => Navigator.pop(ctx),
+              child: const Text('好的')),
+        ],
+      ),
+    );
+  }
+
+  void _showParticipantWaiting() {
+    ScaffoldMessenger.of(context).showSnackBar(
+      const SnackBar(content: Text('已提交，等待发起方确认答案...')),
+    );
+  }
+
+  // ── UI ──
   @override
   Widget build(BuildContext context) {
-    return const Placeholder();
+    // 会话中：PopScope 拦截所有返回方式（AppBar back、系统返回键、Android 物理返回）
+    final Widget body;
+    if (_sessionId == null) {
+      body = _buildRoleSelect();
+    } else {
+      body = PopScope(
+        canPop: false,
+        onPopInvokedWithResult: (didPop, _) async {
+          if (didPop) return; // PopScope 允许了 pop
+          await _handleWillPop();
+        },
+        child: SafeArea(
+          child: Padding(
+            padding: const EdgeInsets.all(16),
+            child: _buildSession(),
+          ),
+        ),
+      );
+    }
+
+    return Scaffold(
+      appBar: AppBar(
+        title: const Text('DualCheck 双验'),
+        centerTitle: true,
+        actions: [
+          IconButton(
+            tooltip: '设置昵称',
+            icon: const Icon(Icons.person),
+            onPressed: _showNicknameDialog,
+          ),
+        ],
+      ),
+      body: body,
+    );
+  }
+
+  // ── PopScope：拦截返回 ──
+  Future<void> _handleWillPop() async {
+    if (_sessionId == null) return;
+    final confirmed = await showDialog<bool>(
+      context: context,
+      builder: (ctx) => AlertDialog(
+        icon: Icon(
+          _myRole == _RoleSelect.initiator
+              ? Icons.warning_amber_rounded
+              : Icons.exit_to_app,
+          size: 40,
+          color: _myRole == _RoleSelect.initiator ? Colors.orange : Colors.blue,
+        ),
+        title: Text(_myRole == _RoleSelect.initiator ? '确定退出会话？' : '确定离开会话？'),
+        content: Text(_myRole == _RoleSelect.initiator
+            ? '退出将结束会话，所有参与者都会收到通知并自动下线，无法恢复。'
+            : '离开后将断开连接，不再接收会话消息。'),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.pop(ctx, false),
+            child: const Text('取消'),
+          ),
+          FilledButton(
+            onPressed: () => Navigator.pop(ctx, true),
+            style: FilledButton.styleFrom(
+              backgroundColor: _myRole == _RoleSelect.initiator ? Colors.red : null,
+            ),
+            child: Text(_myRole == _RoleSelect.initiator ? '结束并退出' : '离开'),
+          ),
+        ],
+      ),
+    );
+    if (confirmed == true && mounted) {
+      if (_myRole == _RoleSelect.initiator) {
+        await _endSession(); // 广播 session_ended + 删 Redis → 参与者自动下线
+      } else {
+        _reset();
+      }
+    }
+  }
+
+  // ── 首页：选择角色 ──
+  Widget _buildRoleSelect() {
+    return Column(
+      crossAxisAlignment: CrossAxisAlignment.stretch,
+      children: [
+        const SizedBox(height: 32),
+        const Text('双验',
+            textAlign: TextAlign.center,
+            style: TextStyle(fontSize: 32, fontWeight: FontWeight.bold)),
+        const SizedBox(height: 8),
+        const Text('多人各输入一段文字，看谁和发起方一致',
+            textAlign: TextAlign.center,
+            style: TextStyle(color: Colors.grey)),
+        const SizedBox(height: 24),
+        Container(
+          padding: const EdgeInsets.all(12),
+          decoration: BoxDecoration(
+            color: Colors.grey.shade100,
+            borderRadius: BorderRadius.circular(8),
+          ),
+          child: Row(
+            children: [
+              const Icon(Icons.person, color: Colors.grey),
+              const SizedBox(width: 8),
+              const Text('当前昵称：'),
+              Text(_nickname,
+                  style: const TextStyle(fontWeight: FontWeight.bold)),
+              const Spacer(),
+              TextButton(
+                onPressed: _showNicknameDialog,
+                child: const Text('修改'),
+              ),
+            ],
+          ),
+        ),
+        const Spacer(),
+        ElevatedButton.icon(
+          onPressed: _isLoading ? null : _createSession,
+          icon: const Icon(Icons.add_circle_outline),
+          label: Text(_isLoading ? '创建中...' : '我是发起方'),
+          style: ElevatedButton.styleFrom(
+              padding: const EdgeInsets.symmetric(vertical: 16)),
+        ),
+        const SizedBox(height: 12),
+        OutlinedButton.icon(
+          onPressed: _isLoading ? null : _showJoinDialog,
+          icon: const Icon(Icons.login),
+          label: const Text('我是参与方'),
+          style: OutlinedButton.styleFrom(
+              padding: const EdgeInsets.symmetric(vertical: 16)),
+        ),
+        if (_errorMsg != null) _buildError(_errorMsg!),
+        const SizedBox(height: 24),
+      ],
+    );
+  }
+
+  // ── 会话页（发起方和参与方共用） ──
+  Widget _buildSession() {
+    if (_myRole == _RoleSelect.initiator) {
+      return _buildInitiatorView();
+    } else {
+      return _buildParticipantView();
+    }
+  }
+
+  // 发起方视图
+  Widget _buildInitiatorView() {
+    final initReady = _session?.initiatorReady ?? false;
+    final participants = _session?.participants ?? [];
+    final initNick = _session?.initiatorNickname ?? _nickname;
+
+    return Column(
+      crossAxisAlignment: CrossAxisAlignment.stretch,
+      children: [
+        _buildSessionBar(),
+        const SizedBox(height: 16),
+        // 发起方输入框（标准答案）
+        if (!initReady) ...[
+          TextField(
+            controller: _textCtrl,
+            maxLines: 4,
+            maxLength: 10000,
+            decoration: const InputDecoration(
+              hintText: '请输入你的答案（标准答案）...',
+              border: OutlineInputBorder(),
+            ),
+          ),
+          const SizedBox(height: 12),
+          ElevatedButton(
+            onPressed: _isLoading ? null : _submit,
+            child: _isLoading
+                ? const CircularProgressIndicator(strokeWidth: 2, color: Colors.white)
+                : const Text('提交标准答案'),
+          ),
+          if (_errorMsg != null) _buildError(_errorMsg!),
+        ] else ...[
+          Container(
+            padding: const EdgeInsets.all(12),
+            decoration: BoxDecoration(
+              color: Colors.green.shade50,
+              borderRadius: BorderRadius.circular(8),
+            ),
+            child: Row(
+              children: [
+                Icon(Icons.check_circle, color: Colors.green.shade700),
+                const SizedBox(width: 8),
+                Expanded(
+                  child: Text('标准答案已提交（$initNick）',
+                      style: TextStyle(color: Colors.green.shade700)),
+                ),
+              ],
+            ),
+          ),
+        ],
+        const SizedBox(height: 24),
+
+        // 参与者列表
+        Row(
+          children: [
+            const Text('参与者',
+                style: TextStyle(fontSize: 16, fontWeight: FontWeight.bold)),
+            const Spacer(),
+            Container(
+              padding:
+                  const EdgeInsets.symmetric(horizontal: 8, vertical: 2),
+              decoration: BoxDecoration(
+                color: Colors.blue.shade100,
+                borderRadius: BorderRadius.circular(12),
+              ),
+              child: Text('${participants.length} 人',
+                  style: TextStyle(
+                      color: Colors.blue.shade800,
+                      fontSize: 12,
+                      fontWeight: FontWeight.bold)),
+            ),
+          ],
+        ),
+        const SizedBox(height: 8),
+        if (participants.isEmpty)
+          Expanded(
+            child: Center(
+              child: Column(
+                mainAxisSize: MainAxisSize.min,
+                children: [
+                  Icon(Icons.group_outlined,
+                      size: 48, color: Colors.grey.shade300),
+                  const SizedBox(height: 8),
+                  const Text('暂无参与者，把会话码分享给他们吧',
+                      style: TextStyle(color: Colors.grey)),
+                ],
+              ),
+            ),
+          )
+        else
+          Expanded(
+            child: ListView.separated(
+              itemCount: participants.length,
+              separatorBuilder: (_, _) => const SizedBox(height: 8),
+              itemBuilder: (_, i) =>
+                  _buildParticipantCard(participants[i]),
+            ),
+          ),
+
+        // 发起方控制区
+        SwitchListTile.adaptive(
+          contentPadding: const EdgeInsets.symmetric(horizontal: 4),
+          title: const Text('允许参与者重新提交'),
+          subtitle: const Text('开启后参与者可以覆盖之前的提交结果'),
+          value: _session?.allowResubmit ?? false,
+          onChanged: _toggleResubmit,
+        ),
+        const SizedBox(height: 8),
+        ElevatedButton(onPressed: _confirmAndEndSession, child: const Text('结束会话')),
+      ],
+    );
+  }
+
+  Widget _buildParticipantCard(ParticipantResp p) {
+    IconData icon;
+    Color color;
+    String status;
+    if (!p.submitted) {
+      icon = Icons.hourglass_empty;
+      color = Colors.orange;
+      status = '等待提交';
+    } else if (p.match == null) {
+      icon = Icons.check_circle;
+      color = Colors.blue;
+      status = '已提交';
+    } else if (p.match == true) {
+      icon = Icons.check_circle;
+      color = Colors.green;
+      status = '正确 ✓';
+    } else {
+      icon = Icons.cancel;
+      color = Colors.red;
+      status = '错误 ✗';
+    }
+
+    return Container(
+      padding: const EdgeInsets.all(12),
+      decoration: BoxDecoration(
+        color: Colors.grey.shade50,
+        borderRadius: BorderRadius.circular(8),
+        border: Border.all(color: Colors.grey.shade200),
+      ),
+      child: Row(
+        children: [
+          Icon(icon, size: 20, color: color),
+          const SizedBox(width: 10),
+          Expanded(
+            child: Text(
+              p.nickname,
+              style: const TextStyle(fontWeight: FontWeight.w500),
+            ),
+          ),
+          Container(
+            padding:
+                const EdgeInsets.symmetric(horizontal: 8, vertical: 2),
+            decoration: BoxDecoration(
+              color: color.withValues(alpha: 0.15),
+              borderRadius: BorderRadius.circular(12),
+            ),
+            child: Text(status,
+                style: TextStyle(color: color, fontSize: 12, fontWeight: FontWeight.w600)),
+          ),
+        ],
+      ),
+    );
+  }
+
+  // 参与者视图
+  Widget _buildParticipantView() {
+    final initReady = _session?.initiatorReady ?? false;
+    final initNick = _session?.initiatorNickname ?? '(发起方)';
+
+    return Column(
+      crossAxisAlignment: CrossAxisAlignment.stretch,
+      children: [
+        _buildSessionBar(),
+        const SizedBox(height: 16),
+
+        // 发起方状态
+        Container(
+          padding: const EdgeInsets.all(12),
+          decoration: BoxDecoration(
+            color: initReady ? Colors.green.shade50 : Colors.orange.shade50,
+            borderRadius: BorderRadius.circular(8),
+          ),
+          child: Row(
+            children: [
+              Icon(
+                  initReady
+                      ? Icons.check_circle
+                      : Icons.hourglass_empty,
+                  color: initReady ? Colors.green : Colors.orange),
+              const SizedBox(width: 8),
+              Expanded(
+                child: Text(
+                  initReady
+                      ? '发起方 $initNick 已提交标准答案'
+                      : '发起方 $initNick 还没提交，先提交你自己的也可以',
+                  style: TextStyle(
+                      color:
+                          initReady ? Colors.green.shade700 : Colors.orange.shade700),
+                ),
+              ),
+            ],
+          ),
+        ),
+        const SizedBox(height: 16),
+
+        // 自己的输入框
+        TextField(
+          controller: _textCtrl,
+          maxLines: 4,
+          maxLength: 10000,
+          decoration: const InputDecoration(
+            hintText: '请输入你的答案...',
+            border: OutlineInputBorder(),
+          ),
+        ),
+        const SizedBox(height: 12),
+        ElevatedButton(
+          onPressed: _isLoading ? null : _submit,
+          child: _isLoading
+              ? const CircularProgressIndicator(strokeWidth: 2, color: Colors.white)
+              : const Text('提交'),
+        ),
+
+        if (_errorMsg != null) _buildError(_errorMsg!),
+
+        const Spacer(),
+        ElevatedButton(onPressed: _reset, child: const Text('离开会话')),
+      ],
+    );
+  }
+
+  // ── 通用组件 ──
+
+  Widget _buildSessionBar() {
+    return Container(
+      padding: const EdgeInsets.all(12),
+      decoration: BoxDecoration(
+        color: Colors.grey.shade100,
+        borderRadius: BorderRadius.circular(8),
+      ),
+      child: Row(
+        children: [
+          const Icon(Icons.share, size: 18, color: Colors.grey),
+          const SizedBox(width: 8),
+          Expanded(
+            child: Text(
+              _sessionId ?? '',
+              style: const TextStyle(fontFamily: 'monospace', fontSize: 13),
+            ),
+          ),
+          IconButton(
+            tooltip: '复制',
+            onPressed: () => _copy(_sessionId ?? ''),
+            icon: const Icon(Icons.copy, size: 18),
+          ),
+          const SizedBox(width: 8),
+          Container(
+            padding:
+                const EdgeInsets.symmetric(horizontal: 8, vertical: 2),
+            decoration: BoxDecoration(
+              color: _myRole == _RoleSelect.initiator
+                  ? Colors.blue.shade100
+                  : Colors.orange.shade100,
+              borderRadius: BorderRadius.circular(4),
+            ),
+            child: Text(
+              _myRole == _RoleSelect.initiator ? '发起方' : '参与方',
+              style: TextStyle(
+                  color: _myRole == _RoleSelect.initiator
+                      ? Colors.blue.shade800
+                      : Colors.orange.shade800,
+                  fontSize: 12,
+                  fontWeight: FontWeight.bold),
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+
+  Future<void> _copy(String text) async {
+    await Clipboard.setData(ClipboardData(text: text));
+    if (!mounted) return;
+    ScaffoldMessenger.of(context)
+        .showSnackBar(const SnackBar(content: Text('已复制')));
+  }
+
+  Widget _buildError(String msg) {
+    return Padding(
+      padding: const EdgeInsets.only(top: 12),
+      child: Container(
+        padding: const EdgeInsets.all(10),
+        decoration: BoxDecoration(
+            color: Colors.red.shade50,
+            borderRadius: BorderRadius.circular(6)),
+        child: Row(
+          children: [
+            const Icon(Icons.error_outline, size: 18, color: Colors.red),
+            const SizedBox(width: 8),
+            Expanded(child: Text(msg, style: const TextStyle(color: Colors.red))),
+          ],
+        ),
+      ),
+    );
+  }
+}
+
+// ── ParticipantResp.copyWith 辅助扩展 ──
+
+extension _ParticipantCopy on ParticipantResp {
+  ParticipantResp copyWith({
+    String? nickname,
+    bool? joined,
+    bool? submitted,
+    bool? match,
+  }) {
+    return ParticipantResp(
+      nickname: nickname ?? this.nickname,
+      joined: joined ?? this.joined,
+      submitted: submitted ?? this.submitted,
+      match: match ?? this.match,
+    );
+  }
+}
+
+extension _SessionCopy on SessionResp {
+  SessionResp copyWith({
+    String? sessionId,
+    String? initiatorNickname,
+    bool? initiatorReady,
+    bool? allowResubmit,
+    List<ParticipantResp>? participants,
+    int? ttlSeconds,
+  }) {
+    return SessionResp(
+      sessionId: sessionId ?? this.sessionId,
+      initiatorNickname: initiatorNickname ?? this.initiatorNickname,
+      initiatorReady: initiatorReady ?? this.initiatorReady,
+      allowResubmit: allowResubmit ?? this.allowResubmit,
+      participants: participants ?? this.participants,
+      ttlSeconds: ttlSeconds ?? this.ttlSeconds,
+    );
   }
 }

client/lib/modules/dual_check/nickname_service.dart

@@ -0,0 +1,33 @@
+// 全局昵称设置
+// 持久化到 SharedPreferences / localStorage，所有工具共享同一个昵称
+import 'package:shared_preferences/shared_preferences.dart';
+
+const _keyNickname = 'toolbox.nickname';
+
+class NicknameService {
+  NicknameService._();
+  static final NicknameService instance = NicknameService._();
+
+  SharedPreferences? _prefs;
+
+  Future<void> _ensureInit() async {
+    _prefs ??= await SharedPreferences.getInstance();
+  }
+
+  /// 获取当前昵称，未设置时返回默认昵称
+  Future<String> get nickname async {
+    await _ensureInit();
+    final n = _prefs!.getString(_keyNickname);
+    if (n != null && n.trim().isNotEmpty) return n.trim();
+    return '用户';
+  }
+
+  /// 设置昵称（1-32 字符，过短返回 false）
+  Future<bool> setNickname(String value) async {
+    final trimmed = value.trim();
+    if (trimmed.isEmpty || trimmed.length > 32) return false;
+    await _ensureInit();
+    await _prefs!.setString(_keyNickname, trimmed);
+    return true;
+  }
+}