//
// flutter bluetooth demo with provider plugin
//
// if you're having problem connecting, quit the app
//   turn off bluetooth on the tablet/phone
//   turn on bluetooth on the tablet/phone
//     it always works for me
//
// add to pubspec.yaml
//   provider: ^4.0.5+1
//   flutter_blue: ^0.7.2
//
// in file anroid/app/build.gradle
//   line 42 - change minSdkVersion to at least 19
//
//////////////////////// main. dart ///////////////////////
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import './notify_value.dart';
import './home.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override  
  Widget build(BuildContext bc) => MaterialApp( 
    home: MultiProvider(  
      providers: [  
        ChangeNotifierProvider<NotifyValue>(create:(_) => NotifyValue())
      ],

      child: Home(),
    )
  );
}
//////////////////////// home.dart ////////////////////////
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import './notify_value.dart';
import './ble.dart';

class Home extends StatefulWidget {
  const Home({ Key key }) : super(key: key);

  @override
  HomeState createState() => HomeState();
}

class HomeState extends State {

  String note = "bluetooth demo, if you're having problem\n"
              + "connecting, quit the program, then turn on/off\n"
              + "bluetooth settings on the table/phone, then\n"
              + "start the program again.";

  Ble ble;

  @override
  initState(){
    super.initState();
    ble = Ble(context);
  }

  @override
  Widget build(BuildContext context) {
    String data = Provider.of<NotifyValue>(context).value;
    return Scaffold( 
      body: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: <Widget>[
        SizedBox(height: 50),
        Text(note),
        SizedBox(height: 50),
        Text("searching for: ${Ble.deviceName}"),
        SizedBox(height: 20),
        Text("service UUID: ${Ble.serviceUuid}"),
        SizedBox(height: 20),
        Text("characteristic UUID: ${Ble.charUuid}"),
        SizedBox(height: 30),
        Text(data, style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold)),

      ],),  
    );
  }
}
/////////////////////// ble.dart //////////////////////////
import 'package:flutter/material.dart';
import 'package:flutter_blue/flutter_blue.dart';
import 'package:provider/provider.dart';
import './notify_value.dart';

class Ble {

  static String deviceName = "Adafruit Bluefruit LE";
  static String serviceUuid = "6e400001-b5a3-f393-e0a9-e50e24dcca9e";
  static String charUuid = "6e400003-b5a3-f393-e0a9-e50e24dcca9e";

  BuildContext bcArg;

  Ble(BuildContext this.bcArg) {

    // start scan
    //Provider.of<NotifyValue>(bcArg, listen: false).setData("Scanning...");
    FlutterBlue.instance
        .startScan(timeout: Duration(seconds: 6))
        .whenComplete(() {
      FlutterBlue.instance.stopScan();
      _scanResult();
    });
  }

// check scan result
_scanResult() {
    FlutterBlue.instance.scanResults.first.then((element) {
      element.forEach((value) {
        if (value.device.name == deviceName) {
            Provider.of<NotifyValue>(bcArg, listen: false).setData("Found device: $deviceName");
          _connectDevice(value.device);
        }
      });
    });
  }

// conect do device
 _connectDevice(BluetoothDevice _device)async {
    
    try {
      await _device.connect();
      _discoverServices(_device);
    } catch (e) {
      if (e.code != 'already_connected') {
        throw e;
      }
    } 
 }

_discoverServices(BluetoothDevice _device) async {
  List<BluetoothService> services = await _device.discoverServices();
    services.forEach((service) {
      
      if (service.uuid.toString() == serviceUuid) {
        Provider.of<NotifyValue>(bcArg, listen: false).setData("Found service: $serviceUuid");
        service.characteristics.forEach((c) {
          if (c.uuid.toString() == charUuid) {
            Provider.of<NotifyValue>(bcArg, listen: false).setData("Found char: $charUuid");
            _handleNotifyChar(c);
          }
        });
      }
    });
  }

_handleNotifyChar(BluetoothCharacteristic bc) async {
  await bc.setNotifyValue(true);
  bc.value.listen((data){
    Provider.of<NotifyValue>(bcArg, listen: false).setData(String.fromCharCodes(data));
  });
}
}

/////////////////////// notify_value.dart ///////////////////
import 'package:flutter/material.dart';

class NotifyValue with ChangeNotifier {
  String _value = "";
  String get value => _value;

  NotifyValue() {
    _value = "no data";
  }

  void setData(String newValue) {
    _value = newValue;
    notifyListeners();
  }
}