import 'dart:async';
import 'package:flutter_blue_plus/flutter_blue_plus.dart';

class BluetoothHelper {
  static StreamSubscription<BluetoothAdapterState>? _subscription;

  /// 获取当前蓝牙是否开启（跨平台封装）
  static Future<bool> isBluetoothOn({Duration timeout = const Duration(seconds: 2)}) async {
    // 先尝试直接获取（Android 上几乎即时可用）
    bool directCheck = await FlutterBluePlus.isOn;
    if (directCheck) return true;

    // iOS 上有初始化延迟，用 adapterState.first 再确认一次
    try {
      BluetoothAdapterState state = await FlutterBluePlus.adapterState
          .firstWhere((s) => s != BluetoothAdapterState.unknown,
              orElse: () => BluetoothAdapterState.unknown)
          .timeout(timeout);

      return state == BluetoothAdapterState.on;
    } catch (_) {
      return false;
    }
  }

  /// 监听蓝牙状态变化
  static void listenBluetoothState(void Function(bool isOn) onChange) {
    _subscription?.cancel();
    _subscription = FlutterBluePlus.adapterState.listen((state) {
      onChange(state == BluetoothAdapterState.on);
    });
  }

  /// 停止监听
  static void cancelListener() {
    _subscription?.cancel();
    _subscription = null;
  }
}