///////////////////////// filename: main.dart
// ble demo
// uses hm19 ble module - amazon item #8541588324
// pico pin4       - hm-19 rxd
// pico pin5       - hm-19 txd
// pico pin40      - hm-19 vcc
/*
flutter 2.2.0 channel stable
tools dart 2.13.0
pubspec.yaml
dependencies:
  flutter:
    sdk: flutter
  flutter_reactive_ble: ^3.1.1
  
 pico uart test
from machine import UART, Pin
import time
uart=UART(1,9600)
while 1:
    while uart.any() > 0:
        print(ord(uart.read(1)))
*/
import 'package:flutter/material.dart';
import 'package:flutter_reactive_ble/flutter_reactive_ble.dart';
import 'ble.dart';
import 'sendbutton.dart';
import 'connectbutton.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      home: MyHomePage(title: 'BLE demo'),);}}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key? key, required this.title}) : super(key: key);

  final String title;

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

class MyHomePageState extends State<MyHomePage> with TickerProviderStateMixin {

  late TabController tabController;
  BLE ble = BLE();
  String status = 'not connected';
  
  @override
  void initState(){
    super.initState();
    tabController = TabController(length: 3, vsync: this);
    tabController.addListener((){
      setState((){
        status = ble.getStatus();
      });
    });
  }
  
  @override
  Widget build(BuildContext context) {
    status = ble.getStatus();
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
        backgroundColor: Colors.black,
        bottom: TabBar(
          controller: tabController,
          indicator: BoxDecoration(
            borderRadius: BorderRadius.circular(50),
            color: Colors.greenAccent),
          tabs: const <Widget>[
            Tab(icon: Icon(Icons.home)),
            Tab(icon: Icon(Icons.light_mode)),
            Tab(icon: Icon(Icons.thermostat)),
          ],),),
          
      body: TabBarView(
        controller: tabController,
        children: <Widget>[
        
            ConnectButton(ble),
              
            SendButton(ble),

           Text('ble is: $status')

        ]));}}
        
//////////////////////////// filename: ble.dart
import 'package:flutter/material.dart';
import 'package:flutter_reactive_ble/flutter_reactive_ble.dart';
import 'dart:async';

class BLE{

  BLE();
  
  final frb = FlutterReactiveBle();
  StreamSubscription? subscription;
  late StreamSubscription<ConnectionStateUpdate> connection;
  late QualifiedCharacteristic tx;
  String status = 'not connected';

  Future<void> stopScan() async {
    await subscription?.cancel();
    subscription = null;
  }
  
  String getStatus(){
    return status;
  }
  
  void sendData() async {
    print('sending...');
    await frb.writeCharacteristicWithResponse(tx, value:[0x41,0x42,0x43]);
  }


 void connectToBLE() async {
    subscription = frb.scanForDevices(withServices:
      [Uuid.parse("0000ffe0-0000-1000-8000-00805f9b34fb")]).listen((device){
        
        connection = frb.connectToDevice(id: device.id).listen((state){
          if (state.connectionState == DeviceConnectionState.connected) {
            tx = QualifiedCharacteristic(
              serviceId: Uuid.parse("0000ffe0-0000-1000-8000-00805f9b34fb"), 
              characteristicId: Uuid.parse("0000ffe1-0000-1000-8000-00805f9b34fb"), 
              deviceId: device.id
            );
            status = 'connected';
            stopScan();
          }
        
        }, onError: (Object e) { // connecting error
          print('error: $e\n');
        });
        
      }, onError:(Object e){ // scan error
        print('error: $e\n');
    });    
  }
 }
 
///////////////////////////// filename: connectbutton.dart
import 'package:flutter/material.dart';
import 'ble.dart';

class ConnectButton extends StatelessWidget {

  final BLE ble;
  ConnectButton(this.ble);

  @override
  Widget build(BuildContext c){
    return RaisedButton(
      child: Text('connect'),
      onPressed: ble.connectToBLE);
  }
}

/////////////////////// filename: sendbutton.dart
import 'package:flutter/material.dart';
import 'ble.dart';

class SendButton extends StatelessWidget {

  final BLE ble;
  SendButton(this.ble);

  @override
  Widget build(BuildContext c){
    return ElevatedButton(
      child: Text('send ABC'),
      onPressed: ble.sendData);
  }
}