//
// flutter bluetooth notify characteristic example
// 
// change android/app/build.gradle
//    line 42 minSDKVersion to at least 19
//
// pubspec yaml: flutter_ble_lib: ^2.2.4
//
// troubleshooting things to try:
//
//   0) use nRF Connect app to find out info:
//     01: device name
//     02: services uuid
//     03: characteristic uuid
//     04: characteristic read | write | notify
//
//   1) make sure bluetooth is enable on phone
//   2) make sure location is enable on phone
//   3) in settings make sure this app has location permission
//   4) turn on/off bluetooth on the phone
//   5) on bluetooth scan setting on the phone, unpair the device
//   6) unplug/plug the bluetooth device
//   7) if app seems stuck, disconnect wait a few seconds
//   8) start app again
//   9) if problem persist kill app task then start again
//  10) how to kill app in samsung galaxy s8
//  11)   swipe first of 3 bottom bar
//  12)   close all app or just this app
//  13) on linux use cutecom terminal - /dev/ttyUSB0 to test
//  14) it's helpful if your bluetooth device has indication of connection
//  15)   on Adafruit I'm using, blinking red 2x means disconnected
//
//      device assumptions - https://www.adafruit.com/product/2269
//                     name: "Adafruit Bluefruit LE"
//                  service: "6e400001-b5a3-f393-e0a9-e50e24dcca9e"
//    notify characteristic: "6//
// flutter bluetooth notify characteristic example
// 
// change android/app/build.gradle
//    line 42 minSDKVersion to at least 19
//
// pubspec yaml: flutter_ble_lib: ^2.2.4
//
// troubleshooting things to try:
//
//   0) use nRF Connect app to find out info:
//     01: device name
//     02: services uuid
//     03: characteristic uuid
//     04: characteristic read | write | notify
//
//   1) make sure bluetooth is enable on phone
//   2) make sure location is enable on phone
//   3) in settings make sure this app has location permission
//   4) turn on/off bluetooth on the phone
//   5) on bluetooth scan setting on the phone, unpair the device
//   6) unplug/plug the bluetooth device
//   7) if app seems stuck, disconnect wait a few seconds
//   8) start app again
//   9) if problem persist kill app task then start again
//  10) how to kill app in samsung galaxy s8
//  11)   swipe first of 3 bottom bar
//  12)   close all app or just this app
//  13) on linux use cutecom terminal - /dev/ttyUSB0 to test
//  14) it's helpful if your bluetooth device has indication of connection
//  15)   on Adafruit I'm using, blinking red 2x means disconnected
//
//      device assumptions - https://www.adafruit.com/product/2269
//                     name: "Adafruit Bluefruit LE"
//                  service: "6e400001-b5a3-f393-e0a9-e50e24dcca9e"
//    notify characteristic: "6e400003-b5a3-f393-e0a9-e50e24dcca9e"
// 
//    note: this device uses UART service which is very slow
//          sometimes the characters are overrun so give it plenty
//          of time before sending data, but it's convenient to
//          debug your flutter bluetooth app
//

import 'dart:async';
//import 'dart:io';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_ble_lib/flutter_ble_lib.dart';
void main() {runApp(MyApp());}

class MyApp extends StatelessWidget {
 
  @override
  Widget build(BuildContext context) {
    return MaterialApp(title: 'Flutter Demo', home: Home());}}

class Home extends StatefulWidget {
  Home({Key key, this.title}) : super(key: key);
  final String title;
  @override
  _HomeState createState() => _HomeState();}

class _HomeState extends State<Home> {

static bool isConnected = false;

BleManager ble = BleManager();
Peripheral peri;
StreamSubscription<CharacteristicWithValue> streamSub;
String dataReceived = "starting app...";
String status = "";

connectToBle() async {
  await ble.createClient();

  ble.startPeripheralScan()
  .listen((scanResult) async {
    
    setState(() => status = "********** scanning for Adafruit Bluefruit LE");
    if (scanResult.peripheral.name == "Adafruit Bluefruit LE") {//device name
      setState(() => status = "********** found device");
      peri = scanResult.peripheral;
      await ble.stopPeripheralScan();
      Timer(Duration(seconds: 1), (){});

      isConnected = await peri.isConnected();
      print("******** ${isConnected.toString}");
      Timer(Duration(seconds: 1), (){});

      setState(() => status = "************* connecting...");
      if (!isConnected && peri != null) { await peri.connect(isAutoConnect: false);}
      else {
        setState(() => "********* error, restarts the program");
        Timer(Duration(seconds: 3),
          () => SystemNavigator.pop(),
        );
      }

      setState(() => status = "***** discovering services and chars");
      await peri.discoverAllServicesAndCharacteristics();

      setState(() => status = "****** setting monitor char");
      streamSub = peri.monitorCharacteristic(   //FlutterBleLib issue 447
        "6e400001-b5a3-f393-e0a9-e50e24dcca9e", // service
        "6e400003-b5a3-f393-e0a9-e50e24dcca9e") // characteristic
       .listen((data) {
         setState(() => dataReceived = String.fromCharCodes(data.value));
         setState(() => status = "");
       });
       setState(() => status = "**** ready to received !!!");
    }});}

// disconnect bluetooth then quit program
disconnect() async {
  setState(() => status = "******* disconnecting now...");
  await streamSub.cancel();
  await peri.disconnectOrCancelConnection();
  await ble.destroyClient();
  setState(() => status = "####### exiting app now... ********");
  Timer(Duration(seconds: 3),
    () => SystemNavigator.pop(),
  );
}

@override  
void initState() {
  super.initState();
  connectToBle();}

  @override
  Widget build(BuildContext context){
    return Scaffold(

      body: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children:[

          SizedBox(height: 50.0),

          Text("     status: ---> $status", 
            style: TextStyle(fontWeight: FontWeight.bold),),

          SizedBox(height: 20.0),

          Padding(
            padding: const EdgeInsets.all(20.0),
            child: Text("if app is stuck, press disconnect a few times, kill the app then restarts"),
          ),

          SizedBox(height: 50.0),

          Padding(
            padding: const EdgeInsets.all(30.0),
            child: Text("data received: $dataReceived"),
          ),

          Padding(
            padding: const EdgeInsets.all(20.0),
            child: RaisedButton(  
              onPressed:() => disconnect(),
              child: Text('disconnect'),
            ),
          ),

      ]),);}}