import 'package:flutter/material.dart';

import 'dart:math';
import 'dart:ui';

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

class MyApp extends StatelessWidget {

  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Flutter Demo',
      theme: new ThemeData(
        primarySwatch: Colors.red,
      ),
      home: new MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

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

  final String title;

  @override
  _MyHomePageState createState() => new _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> with TickerProviderStateMixin{

  String batterylevel;
  int percentage = 0;
  int newPercentage;
  AnimationController percentageAnimationController;

  @override
  void initState() {
    super.initState();
    setState(() {
        percentage = 0;
    });
    percentageAnimationController = new AnimationController(
        vsync: this,
        duration: new Duration(milliseconds: 5000)
    )..addListener((){
      setState((){
        percentage = lerpDouble(0.0,newPercentage.toDouble(),percentageAnimationController.value).toInt();
      });
    });
    percentageAnimationController.addStatusListener((state) => print("test: $state"));

  }

  void _fetchdata() {
    setState(() {
      print("before percent : $percentage");
      newPercentage = percentage+10;
      if(newPercentage>=100){
        percentage = 0;
        newPercentage = 0;
      }
      print("percentage : $percentage");
      percentageAnimationController.forward(from: 0.0);
      batterylevel = newPercentage.toString();
      percentage = newPercentage;
      print("battery level : $batterylevel");
    });
  }

  @override
  Widget build(BuildContext context) {

    return new Scaffold(
      appBar: new AppBar(
        title: new Text(widget.title),
      ),
      body: new Center(
        child: new Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            new CustomPaint(
              foregroundPainter: new MyPainter(
              lineColor: Colors.red[50],
              completeColor: Colors.redAccent,
              completePercent: percentage.toDouble(),
              width: 12.0
          ),
          child: new Padding(
            padding: const EdgeInsets.all(32.0),
            child: new Text(
              '$batterylevel',

            ),
          ),
        ),

          ],
        ),
      ),
      floatingActionButton: new FloatingActionButton(
        onPressed: _fetchdata,
        tooltip: 'Refresh',
        child: new Icon(Icons.refresh),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

class MyPainter extends CustomPainter{
  Color lineColor;
  Color completeColor;
  double completePercent;
  double width;
  MyPainter({this.lineColor,this.completeColor,this.completePercent,this.width});
  @override
  void paint(Canvas canvas, Size size) {
    Paint line = new Paint()
        ..color = lineColor
        ..strokeCap = StrokeCap.round
        ..style = PaintingStyle.stroke
        ..strokeWidth = width;
    Paint complete = new Paint()
      ..color = completeColor
      ..strokeCap = StrokeCap.round
      ..style = PaintingStyle.stroke
      ..strokeWidth = width;
    Offset center  = new Offset(size.width/2, size.height/2);
    double radius  = min(size.width/2,size.height/2);
    canvas.drawCircle(
        center,
        radius,
        line
    );
    double arcAngle = 2*pi* (completePercent/100);
    canvas.drawArc(
        new Rect.fromCircle(center: center,radius: radius),
        -pi/2,
        arcAngle,
        false,
        complete
    );
  }
  @override
  bool shouldRepaint(CustomPainter oldDelegate) {
    return true;
  }
}