xianyan/lib/features/auth/services/qrcode_ws_service.dart

/// ============================================================
/// 闲言APP — 二维码登录WebSocket推送服务
/// 创建时间: 2026-06-02
/// 更新时间: 2026-06-02
/// 作用: 通过WebSocket长连接接收二维码状态变更推送，替代HTTP轮询
/// 上次更新: 处理confirmed状态携带token的推送，收到终态后自动取消订阅
/// ============================================================

import 'dart:async';
import 'dart:convert';

import 'package:web_socket_channel/web_socket_channel.dart';
import 'package:xianyan/core/utils/logger.dart';

typedef QrcodeStatusCallback = void Function(Map<String, dynamic> data);

class QrcodeWsService {
  QrcodeWsService._();

  static final QrcodeWsService instance = QrcodeWsService._();

  WebSocketChannel? _channel;
  bool _isConnected = false;
  Timer? _heartbeatTimer;
  Timer? _reconnectTimer;
  int _reconnectAttempts = 0;
  static const _maxReconnectAttempts = 5;

  String? _subscribedCode;
  QrcodeStatusCallback? _onStatusUpdate;
  StreamSubscription<dynamic>? _subscription;

  bool get isConnected => _isConnected;

  /// 连接WebSocket服务器
  Future<bool> connect() async {
    if (_isConnected) return true;

    final wsUrl = _resolveWsUrl();
    if (wsUrl.isEmpty) {
      Log.w('QrcodeWsService: WebSocket URL不可用');
      return false;
    }

    try {
      Log.i('QrcodeWsService: 连接 $wsUrl');
      _channel = WebSocketChannel.connect(Uri.parse(wsUrl));

      await _channel!.ready.timeout(
        const Duration(seconds: 5),
        onTimeout: () => throw TimeoutException('连接超时'),
      );

      _isConnected = true;
      _reconnectAttempts = 0;
      _startHeartbeat();

      _subscription = _channel!.stream.listen(
        (data) => _handleMessage(data),
        onDone: () {
          _isConnected = false;
          Log.w('QrcodeWsService: 连接关闭');
          _scheduleReconnect();
        },
        onError: (Object? e) {
          _isConnected = false;
          Log.e('QrcodeWsService: 连接错误 $e');
          _scheduleReconnect();
        },
      );

      Log.i('QrcodeWsService: 连接成功');
      if (_subscribedCode != null) {
        _sendSubscribe(_subscribedCode!);
      }
      return true;
    } catch (e) {
      Log.w('QrcodeWsService: 连接失败 $e');
      _isConnected = false;
      return false;
    }
  }

  /// 订阅二维码状态变更
  Future<void> subscribe(String code, QrcodeStatusCallback onStatus) async {
    _subscribedCode = code;
    _onStatusUpdate = onStatus;

    if (!_isConnected) {
      final ok = await connect();
      if (!ok) {
        Log.w('QrcodeWsService: WebSocket不可用，将使用HTTP轮询降级');
        return;
      }
    }

    _sendSubscribe(code);
  }

  /// 取消订阅
  void unsubscribe() {
    if (_isConnected && _subscribedCode != null) {
      _send({'type': 'qrcode_unsubscribe', 'code': _subscribedCode});
    }
    _subscribedCode = null;
    _onStatusUpdate = null;
  }

  /// 断开连接
  void disconnect() {
    _subscription?.cancel();
    _subscription = null;
    _heartbeatTimer?.cancel();
    _reconnectTimer?.cancel();
    _channel?.sink.close();
    _channel = null;
    _isConnected = false;
    _subscribedCode = null;
    _onStatusUpdate = null;
    _reconnectAttempts = 0;
    Log.i('QrcodeWsService: 已断开');
  }

  void _sendSubscribe(String code) {
    _send({
      'type': 'qrcode_subscribe',
      'code': code,
    });
    Log.i('QrcodeWsService: 已订阅 $code');
  }

  void _send(Map<String, dynamic> data) {
    if (!_isConnected || _channel == null) return;
    try {
      _channel!.sink.add(jsonEncode(data));
    } catch (e) {
      Log.w('QrcodeWsService: 发送失败 $e');
    }
  }

  void _handleMessage(dynamic data) {
    try {
      final json = jsonDecode(data as String) as Map<String, dynamic>;
      final type = json['type'] as String? ?? '';

      if (type == 'qrcode_status_update') {
        final status = json['status'] as String? ?? '';
        Log.i('QrcodeWsService: 收到状态推送 $status');
        _onStatusUpdate?.call(json);
        if (status == 'confirmed' || status == 'expired' ||
            status == 'cancelled') {
          Log.i('QrcodeWsService: 终态 $status，自动取消订阅');
          unsubscribe();
        }
      } else if (type == 'pong') {
        // heartbeat ack
      }
    } catch (e) {
      Log.w('QrcodeWsService: 消息解析失败 $e');
    }
  }

  void _startHeartbeat() {
    _heartbeatTimer?.cancel();
    _heartbeatTimer = Timer.periodic(const Duration(seconds: 25), (_) {
      _send({'type': 'ping'});
    });
  }

  void _scheduleReconnect() {
    if (_reconnectAttempts >= _maxReconnectAttempts) {
      Log.w('QrcodeWsService: 超过最大重连次数');
      return;
    }
    if (_subscribedCode == null) return;

    _reconnectAttempts++;
    final delay = Duration(seconds: _reconnectAttempts * 2);
    Log.i('QrcodeWsService: ${delay.inSeconds}秒后重连 (第$_reconnectAttempts次)');

    _reconnectTimer?.cancel();
    _reconnectTimer = Timer(delay, () async {
      final ok = await connect();
      if (ok && _subscribedCode != null) {
        _sendSubscribe(_subscribedCode!);
      }
    });
  }

  String _resolveWsUrl() {
    return 'wss://tools.wktyl.com:9443';
  }
}