import 'dart:async';
import 'dart:convert';

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

class AppLocalizations {
  static final AppLocalizations _singleton = new AppLocalizations._internal();
  AppLocalizations._internal();
  static AppLocalizations get instance => _singleton;

  Map<dynamic, dynamic> _localisedValues;
  Locale _currentLocale;

  Future<AppLocalizations> load(Locale locale) async {
    String jsonContent = await rootBundle
        .loadString("locale/locale_${locale.languageCode}.json");
    _localisedValues = json.decode(jsonContent);
    _currentLocale = locale;
    return this;
  }

  String getLocale() {
    return _currentLocale.languageCode;
  }

  String text(String key) {
    return _localisedValues[key] ?? "$key not found";
  }
}

class AppLocalizationsDelegate extends LocalizationsDelegate<AppLocalizations> {
  const AppLocalizationsDelegate();

  @override
  bool isSupported(Locale locale) =>
      ['en', 'pl', 'de'].contains(locale.languageCode);

  @override
  Future<AppLocalizations> load(Locale locale) {
    return AppLocalizations.instance.load(locale);
  }

  @override
  bool shouldReload(AppLocalizationsDelegate old) => true;
}