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

class CurrentDay extends StatefulWidget {
  @override
  _CurrentDayState createState() => _CurrentDayState();
}

class _CurrentDayState extends State<CurrentDay> {
  DateTime now = DateTime.now();
  bool update = true;

  @override
  void initState() {
    super.initState();
    _generateCurrentDateTimes().listen((date) {
      setState(() {
        this.now = date;
      });
    });
  }

  Stream<DateTime> _generateCurrentDateTimes() async* {
    while (update) {
      yield await Future.delayed(Duration(seconds: 1), () => DateTime.now());
    }
  }

  @override
  Widget build(BuildContext context) {
    final polandDateTime = now.add(Duration(hours: 1));
    final japanDateTime = polandDateTime.add(Duration(hours: 8));
    return Container(
      child: Row(
        children: <Widget>[
          _localDateTime(title: "Poland", now: polandDateTime),
          _localDateTime(title: "Japan", now: japanDateTime),
        ],
      ),
    );
  }

  Widget _localDateTime({String title, DateTime now}) {
    final fix = (number) => number < 10 ? "0$number" : "$number";
    final time = "${fix(now.hour)}:${fix(now.minute)}";
    final date = "${fix(now.day)}.${fix(now.month)}.${now.year}";
    final daytime = now.hour > 6 && now.hour < 20;
    final bgColor = daytime ? Colors.lightBlue[100] : Colors.blueGrey[900];
    final fontColor = daytime ? Colors.black : Colors.white;
    return Expanded(
      child: Container(
        padding: EdgeInsets.symmetric(vertical: 16.0),
        color: bgColor,
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.center,
          children: <Widget>[
            Text(title, style: TextStyle(fontSize: 24.0, color: fontColor)),
            Text(date, style: TextStyle( fontSize: 14.0,color: fontColor)),
            Text(time, style: TextStyle(fontSize: 32.0, color: fontColor))
          ],
        ),
      ),
    );
  }

  @override
  void dispose() {
    setState(() {
      this.update = false;
    });
    super.dispose();
  }
}