import 'dart:async';
import 'package:flutter/foundation.dart';
import 'package:qhd_prevention/http/ApiService.dart';
import 'package:qhd_prevention/services/SessionService.dart';

/// 心跳服务 - 单例模式
/// 每5秒发送一次心跳请求
class HeartbeatService {
  HeartbeatService._internal();

  static final HeartbeatService _instance = HeartbeatService._internal();

  factory HeartbeatService() => _instance;

  Timer? _heartbeatTimer;
  bool _isRunning = false;
  bool _isPaused = false; // 用于应用生命周期暂停

  /// 心跳间隔（秒）
  static const Duration heartbeatInterval = Duration(seconds: 5);

  /// 是否正在运行
  bool get isRunning => _isRunning;

  /// 启动心跳
  /// 只有在用户已登录时才会启动
  void start() {
    // 检查是否已登录
    if (!SessionService.instance.isLoggedIn) {
      debugPrint('HeartbeatService: 用户未登录，不启动心跳');
      return;
    }

    // 如果已经在运行，不重复启动
    if (_isRunning && _heartbeatTimer != null) {
      debugPrint('HeartbeatService: 心跳已在运行');
      return;
    }

    _isRunning = true;
    _isPaused = false;
    debugPrint('HeartbeatService: 启动心跳，间隔 ${heartbeatInterval.inSeconds} 秒');

    // 立即发送一次心跳
    _sendHeartbeat();

    // 启动定时器
    _heartbeatTimer = Timer.periodic(heartbeatInterval, (timer) {
      if (!_isPaused && SessionService.instance.isLoggedIn) {
        _sendHeartbeat();
      } else if (!SessionService.instance.isLoggedIn) {
        // 如果用户已退出登录，停止心跳
        stop();
      }
    });
  }

  /// 停止心跳
  void stop() {
    if (_heartbeatTimer != null) {
      _heartbeatTimer!.cancel();
      _heartbeatTimer = null;
    }
    _isRunning = false;
    _isPaused = false;
    debugPrint('HeartbeatService: 停止心跳');
  }

  /// 暂停心跳（应用进入后台时）
  void pause() {
    if (_isRunning) {
      _isPaused = true;
      debugPrint('HeartbeatService: 暂停心跳');
    }
  }

  /// 恢复心跳（应用回到前台时）
  void resume() {
    if (_isRunning && _isPaused) {
      _isPaused = false;
      debugPrint('HeartbeatService: 恢复心跳');
      // 立即发送一次心跳
      _sendHeartbeat();
    }
  }
  /// 发送心跳请求
  Future<void> _sendHeartbeat() async {
    try {
      // 检查登录状态
      if (!SessionService.instance.isLoggedIn) {
        debugPrint('HeartbeatService: 用户未登录，停止心跳');
        stop();
        return;
      }
      // 调用心跳接口
      // await HiddenDangerApi.heartbeat();
      // debugPrint('HeartbeatService: 心跳发送成功');
    } catch (e) {
      debugPrint('HeartbeatService: 心跳发送失败: $e');
      // 心跳失败不停止服务，继续尝试
    }
  }
}