// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'dart:async';

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

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.blue,
      ),
      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> {
  Battery _battery = new Battery();

  BatteryState _batteryState;
  StreamSubscription<BatteryState> _batteryStateSubscription;

  @override
  void initState() {
    super.initState();
    _batteryStateSubscription =
        _battery.onBatteryStateChanged.listen((BatteryState state) {
      setState(() {
        _batteryState = state;
      });
    });
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: const Text('Plugin example app'),
      ),
      body: new Center(
        child: new Text('$_batteryState'),
      ),
      floatingActionButton: new FloatingActionButton(
        child: const Icon(Icons.battery_unknown),
        onPressed: () async {
          final int batteryLevel = await _battery.batteryLevel;
          showDialog<Null>(
            context: context,
            builder: (_) => new AlertDialog(
                  content: new Text('Battery: $batteryLevel%'),
                  actions: <Widget>[
                    new FlatButton(
                      child: const Text('OK'),
                      onPressed: () {
                        Navigator.pop(context);
                      },
                    )
                  ],
                ),
          );
        },
      ),
    );
  }

  @override
  void dispose() {
    super.dispose();
    if (_batteryStateSubscription != null) {
      _batteryStateSubscription.cancel();
    }
  }
}