library flutter_bluetooth;

import 'dart:async';
import 'dart:ffi';
import 'dart:typed_data';

import 'package:flutter/cupertino.dart';
import 'package:flutter/services.dart';
import 'package:rxdart/rxdart.dart';

part 'bluetooth_device.dart';
part 'bluetooth_socket.dart';

class FlutterBluetooth {
  MethodChannel _channel = MethodChannel('flutter_bluetooth');

  PublishSubject _stopScanPill = new PublishSubject();
  List<BluetoothDevice> _scanDevices;

  FlutterBluetooth._();

  static FlutterBluetooth _instance = new FlutterBluetooth._();
  static FlutterBluetooth get instance => _instance;

  Future<bool> get isEnabled async {
    final bool version = await _channel.invokeMethod('isEnabled');
    return version;
  }

  enabled() async {
    await _channel.invokeMethod('enabled');
  }

  Stream<List<BluetoothDevice>> startScan({List<int> filterClasses}) async* {
    bool isSuccess = await _channel.invokeMethod('startScan');
    if(!isSuccess){
      throw ErrorDescription('启动扫描失败');
    }
    _scanDevices = [];
    yield* EventChannel('flutter_bluetooth/scanEvents')
        .receiveBroadcastStream()
        .takeUntil(_stopScanPill)
        .map((item) {
      if (item['isCompleted']) {
        _stopScanPill.add(null);
      } else {
        var device = BluetoothDevice.fromJson(item["data"]);
        if (!_scanDevices.contains(device)) {
          if (filterClasses == null || _filterClass(device, filterClasses)) {
            _scanDevices.add(device);
          }
        }
      }
      return _scanDevices;
    });
  }

  stopScan() async {
    bool isSuccess =  await _channel.invokeMethod('stopScan');
    if(!isSuccess){
      throw ErrorDescription('暂停扫描失败');
    }
    _stopScanPill.add(null);
  }

  bool _filterClass(BluetoothDevice device, List<int> filterClasses) {
    return filterClasses.indexOf(device.deviceClass) >= 0;
  }
}