import 'package:flutter_test/flutter_test.dart';
import 'package:halkyon_app/halkyon_app.dart';
import 'package:material_ui/material_ui.dart';

void main() {
  /// The languages a Halkyon app speaks: British English (the template, as
  /// `en` and `en-GB`), American English and German.
  const supported = [
    Locale('en'),
    Locale('de'),
    Locale('en', 'GB'),
    Locale('en', 'US'),
  ];

  Locale resolved(List<Locale>? preferred) =>
      resolveAppLocale(preferred, supported);

  test('the language asked for, where the app speaks it', () {
    expect(resolved(const [Locale('en', 'US')]), const Locale('en', 'US'));
    expect(resolved(const [Locale('en', 'GB')]), const Locale('en', 'GB'));
    expect(resolved(const [Locale('de', 'DE')]), const Locale('de'));
    expect(resolved(const [Locale('de')]), const Locale('de'));
  });

  test('British English for any other English', () {
    expect(resolved(const [Locale('en')]), const Locale('en', 'GB'));
    expect(resolved(const [Locale('en', 'AU')]), const Locale('en', 'GB'));
  });

  test('the next language the device prefers, where the first is none the '
      'app speaks', () {
    expect(
      resolved(const [Locale('fr', 'FR'), Locale('de', 'AT')]),
      const Locale('de'),
    );
  });

  test('British English where the app speaks none of them', () {
    expect(resolved(const [Locale('fr', 'FR')]), const Locale('en', 'GB'));
    expect(resolved(const []), const Locale('en', 'GB'));
    expect(resolved(null), const Locale('en', 'GB'));
  });

  test('never a language picked by the country alone', () {
    // Spanish in the United States isn't American English.
    expect(resolved(const [Locale('es', 'US')]), const Locale('en', 'GB'));
  });

  test('every language this package speaks is one it resolves to', () {
    for (final locale in HalkyonAppLocalizations.supportedLocales) {
      expect(
        resolveAppLocale([locale], HalkyonAppLocalizations.supportedLocales),
        isIn(HalkyonAppLocalizations.supportedLocales),
        reason: '$locale',
      );
    }
  });
}