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

/// A signed-in person's app as a test makes one: who it is for, and the
/// way to Switch account.
class const _PersonApp(final SignedIn person) extends StatelessWidget {
  @override
  Widget build(BuildContext context) => MaterialApp(
    localizationsDelegates: testLocalizationsDelegates,
    supportedLocales: HalkyonAppLocalizations.supportedLocales,
    home: Scaffold(
      body: Builder(
        builder: (context) => Column(
          children: [
            Text('Home of ${person.authUserId}'),
            TextButton(
              onPressed: () => showAccountSwitcher(context),
              child: const Text('Switch account'),
            ),
          ],
        ),
      ),
    ),
  );
}

void main() {
  final builtIn = Instance.parse('learn.halkyon.eu')!;
  final other = Instance.parse('learn.example.org')!;
  late MemoryInstanceStore store;
  late List<Instance> opened;
  late List<TestAppDependencies> dependencies;
  late List<Instance> forgotten;

  setUp(() {
    store = MemoryInstanceStore();
    opened = [];
    dependencies = [];
    forgotten = [];
  });

  /// Starts the app on a device that [usedBefore] the choice existed, with
  /// [answering] instances answering a check, saying where they keep data
  /// as [locations] has it, and the account on each [signedOut].
  Future<InstanceChoice> start(
    WidgetTester tester, {
    bool usedBefore = false,
    bool signedOut = false,
    Set<Instance> answering = const {},
    Map<Instance, InstanceLocations> locations = const {},
    SubdivisionNames subdivisionNames = const MemorySubdivisionNames({}),
  }) async {
    tester.view.physicalSize = const Size(412, 900);
    tester.view.devicePixelRatio = 1;
    addTearDown(tester.view.reset);
    final choice = InstanceChoice(
      store,
      builtIn: builtIn,
      forget: (instance) async => forgotten.add(instance),
    );
    await choice.load(usedBefore: usedBefore);
    await tester.pumpWidget(
      InstanceGate(
        frame: testFrame(),
        choice: choice,
        checker: FakeInstanceChecker(answering, locations),
        countryNames: MemoryCountryNames(const {
          'CH': {'en': 'Switzerland'},
          'DE': {'en': 'Germany'},
          'US': {'en': 'United States'},
        }),
        subdivisionNames: subdivisionNames,
        readLook: () async => (themeMode: ThemeMode.light, locale: null),
        open: (instance) async {
          opened.add(instance);
          final opening = TestAppDependencies(serverName: instance.name);
          await opening.signedOut.write(signedOut: signedOut);
          dependencies.add(opening);
          return opening;
        },
        app: SessionGate(
          look: (context) => (themeMode: ThemeMode.light, locale: null),
          app: _PersonApp.new,
        ),
      ),
    );
    await tester.pumpAndSettle();
    return choice;
  }

  Future<void> openSwitcher(WidgetTester tester) async {
    await tester.tap(find.text('Switch account'));
    await tester.pumpAndSettle();
  }

  testWidgets('a new install asks for the instance first, and opens the '
      "build's in one tap", (tester) async {
    await start(tester);

    // The wordmark says it to screen readers, naming the app.
    expect(find.bySemanticsLabel('Welcome to Halkyon Test'), findsOneWidget);
    expect(
      find.text('Choose the instance to keep your notes on.'),
      findsOneWidget,
      reason: "the app's own words",
    );
    expect(opened, isEmpty, reason: 'nothing made anywhere yet');
    expect(find.byType(TextField), findsNothing, reason: 'no address asked');

    await tester.tap(find.text('learn.halkyon.eu'));
    await tester.pumpAndSettle();

    expect(opened, [builtIn]);
    expect(find.text('Home of anonymous-1'), findsOneWidget);
  });

  testWidgets("the build's instance shows where it keeps people's data, "
      'once it says', (tester) async {
    await start(
      tester,
      answering: {builtIn},
      locations: {
        builtIn: const InstanceLocations(data: 'EU', backups: 'CH'),
      },
    );

    expect(find.text('Data: European Union\nBackups: Switzerland'), findsOne);
    expect(find.byType(Flag), findsOne);
  });

  testWidgets('an instance may say where more precisely: a state, a region', (
    tester,
  ) async {
    await start(
      tester,
      answering: {builtIn},
      locations: {
        builtIn: const InstanceLocations(data: 'US-CA', backups: 'DE-BY'),
      },
      subdivisionNames: const MemorySubdivisionNames({
        'DE-BY': {'en': 'Bavaria'},
        'US-CA': {'en': 'California'},
      }),
    );

    expect(
      find.text(
        'Data: California, United States\nBackups: Bavaria, Germany (EU)',
      ),
      findsOne,
    );
    expect(find.byType(Flag), findsOne);
  });

  testWidgets('an instance saying nothing, or not answering, comes with the '
      'app, without a flag', (tester) async {
    await start(tester);

    expect(find.text('Comes with the app'), findsOne);
    expect(find.byType(Flag), findsNothing);
  });

  testWidgets('another instance is checked before the app moves there', (
    tester,
  ) async {
    await start(tester, answering: {other});

    await tester.tap(find.text('Another instance'));
    await tester.pumpAndSettle();
    expect(
      FocusManager.instance.primaryFocus?.context
          ?.findAncestorWidgetOfExactType<TextField>(),
      isNotNull,
      reason: 'the address is typed at once',
    );
    expect(
      find.widgetWithText(TextField, 'test.example.org'),
      findsOneWidget,
      reason: "the app's example address as the hint",
    );

    await tester.enterText(find.byType(TextField), 'nowhere.example.org');
    await tester.tap(find.text('Continue'));
    await tester.pumpAndSettle();
    expect(
      find.text('No instance of Halkyon Test answers at nowhere.example.org.'),
      findsOneWidget,
    );
    expect(opened, isEmpty);

    await tester.enterText(find.byType(TextField), 'learn.example.org');
    await tester.tap(find.text('Continue'));
    await tester.pumpAndSettle();
    expect(opened, [other]);
  });

  testWidgets('an install from before goes on without asking', (tester) async {
    await start(tester, usedBefore: true);

    expect(opened, [builtIn]);
    expect(find.text('Home of anonymous-1'), findsOneWidget);
  });

  testWidgets('Switch account moves between the accounts on the device, '
      'closing the app on the one before, and removes one not in '
      'use', (tester) async {
    store = MemoryInstanceStore((current: builtIn, known: [builtIn, other]));
    await start(
      tester,
      answering: {builtIn, other},
      locations: {
        other: const InstanceLocations(
          data: 'CH',
          backups: InstanceLocations.noBackups,
        ),
      },
    );
    await openSwitcher(tester);
    expect(find.text('learn.halkyon.eu'), findsWidgets);
    // Each account with where its instance says it keeps people's data.
    expect(find.text('Data: Switzerland\nNo backups'), findsOne);
    expect(find.byType(Flag), findsOne);
    expect(find.text('Anonymous'), findsOne, reason: 'the account in use');
    await tester.tap(find.text('learn.example.org'));
    await tester.pumpAndSettle();
    expect(opened, [builtIn, other]);
    expect(dependencies.first.disposed, isTrue);
    expect(find.text('Home of anonymous-1'), findsOneWidget);

    await openSwitcher(tester);
    await tester.tap(find.byTooltip('Remove account'));
    await tester.pumpAndSettle();
    await tester.tap(find.widgetWithText(FilledButton, 'Remove'));
    await tester.pumpAndSettle();

    expect(forgotten, [builtIn]);
    expect(store.kept?.known, [other]);
  });

  testWidgets('signed out, the start screen names the instance and offers '
      'another, through Switch account', (tester) async {
    store = MemoryInstanceStore((current: builtIn, known: [builtIn]));
    await start(tester, answering: {builtIn, other}, signedOut: true);

    expect(find.text('Start on learn.halkyon.eu:'), findsOneWidget);
    await tester.tap(find.text('Use another instance'));
    await tester.pumpAndSettle();
    await tester.tap(find.text('Add account'));
    await tester.pumpAndSettle();
    expect(
      find.text('Choose the instance for the account to add.'),
      findsOneWidget,
    );

    await tester.enterText(find.byType(TextField), 'learn.example.org');
    await tester.tap(find.text('Continue'));
    await tester.pumpAndSettle();

    expect(opened, [builtIn, other]);
    expect(find.text('Start on learn.example.org:'), findsOneWidget);
  });

  testWidgets("an instance whose app doesn't open says so, and tries "
      'again', (tester) async {
    store = MemoryInstanceStore((current: builtIn, known: [builtIn]));
    final choice = InstanceChoice(
      store,
      builtIn: builtIn,
      forget: (instance) async {},
    );
    await choice.load(usedBefore: false);
    var attempts = 0;
    await tester.pumpWidget(
      InstanceGate(
        frame: testFrame(),
        choice: choice,
        checker: FakeInstanceChecker(),
        countryNames: MemoryCountryNames(const {}),
        readLook: () async => (themeMode: ThemeMode.light, locale: null),
        open: (instance) async {
          if (++attempts == 1) {
            throw StateError('disk unavailable');
          }
          return TestAppDependencies();
        },
        app: const Directionality(
          textDirection: TextDirection.ltr,
          child: Text('the app'),
        ),
      ),
    );
    await tester.pumpAndSettle();
    expect(find.text("Couldn't open the app on learn.halkyon.eu."), findsOne);

    await tester.tap(find.text('Try again'));
    await tester.pumpAndSettle();

    expect(find.text('the app'), findsOne);
  });
}