import 'dart:async';

import 'package:flutter_bloc/flutter_bloc.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';

/// Where an app puts the sync's widgets: a banner on its home, a dot on its
/// way to Settings, and the Sync card in Settings, which More leads to.
class const _Home() extends StatelessWidget {
  @override
  Widget build(BuildContext context) => Scaffold(
    body: Column(
      children: [
        AppMismatchBanner(onMore: () => _openSettings(context)),
        SyncTroubleBadge(
          child: IconButton(
            tooltip: 'Settings',
            icon: const Icon(Icons.settings),
            onPressed: () => _openSettings(context),
          ),
        ),
      ],
    ),
  );

  static void _openSettings(BuildContext context) => Navigator.of(context).push(
    MaterialPageRoute<void>(
      builder: (context) => Scaffold(
        appBar: AppBar(title: const Text('Settings')),
        body: const SingleChildScrollView(child: SyncStatusCard()),
      ),
    ),
  );
}

void main() {
  /// What the next sync does: null goes through, anything else is thrown.
  late Object? nextSync;

  /// Shows the app on test.example.org once a first sync ran, with
  /// [pending] changes kept from before that haven't reached the server.
  /// (The service isn't started: its timers would outlive the test.)
  Future<void> showApp(WidgetTester tester, {int pending = 0}) async {
    final sync = SyncService(
      ({required onMerge}) => switch (nextSync) {
        final Object error => Future<void>.error(error),
        null => Future<void>.value(),
      },
      pendingChanges: MemoryPendingChangesStore(pending),
    )..syncNow();
    addTearDown(sync.dispose);
    await tester.pumpWidget(
      BlocProvider(
        create: (context) =>
            SyncStatusBloc(sync)..add(const SyncStatusEventStarted()),
        child: testApp(const _Home(), dependencies: TestAppDependencies()),
      ),
    );
    await tester.pumpAndSettle();
  }

  Finder trouble() => find.bySemanticsLabel(RegExp('Sync needs attention'));

  Future<void> openSettings(WidgetTester tester) async {
    await tester.tap(find.byTooltip('Settings'));
    await tester.pumpAndSettle();
  }

  setUp(() => nextSync = null);

  testWidgets('shows nothing while sync goes through', (tester) async {
    await showApp(tester);

    expect(trouble(), findsNothing);
    expect(find.byType(MaterialBanner), findsNothing);
  });

  testWidgets('a failed sync puts a dot on the way to Settings, and the '
      'Sync card says what is wrong', (tester) async {
    nextSync = Exception('No connection');
    await showApp(tester);

    expect(trouble(), findsOneWidget);
    await openSettings(tester);
    expect(find.text('Sync is failing'), findsOneWidget);
    expect(find.textContaining('Last attempt failed at'), findsOneWidget);
    expect(
      find.text('No sync has completed since the app started'),
      findsOneWidget,
    );
  });

  testWidgets('the Sync card counts the changes that wait to sync, until a '
      'sync takes them', (tester) async {
    nextSync = Exception('No connection');
    await showApp(tester, pending: 2);
    await openSettings(tester);

    expect(find.text('Sync is failing'), findsOneWidget);
    expect(find.text('2 changes wait to sync'), findsOneWidget);

    nextSync = null;
    await tester.tap(find.text('Sync now'));
    await tester.pumpAndSettle();
    expect(find.text('Everything synced'), findsOneWidget);
    expect(find.textContaining('wait to sync'), findsNothing);
  });

  testWidgets('Sync now syncs, and the trouble goes once a sync went '
      'through', (tester) async {
    nextSync = Exception('No connection');
    await showApp(tester);
    await openSettings(tester);

    nextSync = null;
    await tester.tap(find.text('Sync now'));
    await tester.pumpAndSettle();

    expect(find.text('Everything synced'), findsOneWidget);
    expect(find.textContaining('Last completed at'), findsOneWidget);
    await tester.pageBack();
    await tester.pumpAndSettle();
    expect(trouble(), findsNothing);
  });

  testWidgets("when the app and the server don't match, the banner says so "
      'and More leads to the Sync card, until a sync goes through', (
    tester,
  ) async {
    nextSync = const AppServerMismatchException();
    await showApp(tester);

    const banner =
        "This app can't sync with test.example.org any more. Update it to "
        'keep syncing.';
    expect(find.text(banner), findsOneWidget);

    await tester.tap(
      find.descendant(
        of: find.byType(MaterialBanner),
        matching: find.text('More'),
      ),
    );
    await tester.pumpAndSettle();
    expect(
      find.text("This app can't sync with test.example.org"),
      findsOneWidget,
    );
    expect(
      find.text(
        'Update the app. If it is up to date, the server needs an update. '
        'What you do meanwhile stays on this device and syncs afterwards.',
      ),
      findsOneWidget,
    );

    nextSync = null;
    await tester.tap(find.text('Sync now'));
    await tester.pumpAndSettle();
    await tester.pageBack();
    await tester.pumpAndSettle();
    expect(find.text(banner), findsNothing);
  });

  testWidgets('an ordinary failure shows no banner', (tester) async {
    nextSync = Exception('No connection');
    await showApp(tester);

    expect(find.textContaining('Update it to keep syncing'), findsNothing);
  });

  group('on mobile data (ADR 0042)', () {
    late FakeNetworkWatch network;
    late int syncs;

    /// Shows the banner above the Sync card, on a phone ([offered]) on
    /// mobile data, sync started; [changes] made here wait.
    Future<(SyncService, MobileDataGate)> showPhone(
      WidgetTester tester, {
      bool offered = true,
      int changes = 0,
    }) async {
      final gate = MobileDataGate(network: network, offered: offered);
      addTearDown(gate.dispose);
      final sync = SyncService(({required onMerge}) async {
        syncs++;
      }, mobileData: gate)..start();
      for (var change = 0; change < changes; change++) {
        sync.requestSync();
      }
      await tester.pumpWidget(
        BlocProvider(
          create: (context) =>
              SyncStatusBloc(sync)..add(const SyncStatusEventStarted()),
          child: testApp(
            Scaffold(
              body: Builder(
                builder: (context) => Column(
                  children: [
                    ?mobileDataBannerOf(context),
                    const Expanded(
                      child: SingleChildScrollView(child: SyncStatusCard()),
                    ),
                  ],
                ),
              ),
            ),
            dependencies: TestAppDependencies(),
          ),
        ),
      );
      await tester.pump(const Duration(seconds: 3));
      await tester.pumpAndSettle();
      return (sync, gate);
    }

    setUp(() {
      network = FakeNetworkWatch()..state = FakeNetworkWatch.mobile;
      syncs = 0;
    });

    testWidgets('the banner counts the changes waiting; Not now puts it off '
        'until another waits', (tester) async {
      final (sync, _) = await showPhone(tester, changes: 2);
      expect(find.text('On mobile data · 2 changes waiting'), findsOneWidget);
      expect(find.text('Held back on mobile data'), findsOneWidget);
      expect(syncs, 0);

      await tester.tap(find.text('Not now'));
      await tester.pumpAndSettle();
      expect(find.byType(MobileDataBanner), findsNothing);

      sync.requestSync();
      await tester.pump(const Duration(seconds: 3));
      await tester.pumpAndSettle();
      expect(find.text('On mobile data · 3 changes waiting'), findsOneWidget);
      expect(syncs, 0);
      unawaited(sync.dispose());
    });

    testWidgets('Sync now syncs and the banner goes', (tester) async {
      final (sync, _) = await showPhone(tester);
      expect(find.text('On mobile data · sync paused'), findsOneWidget);

      await tester.tap(find.text('Sync now').first);
      await tester.pumpAndSettle();
      expect(syncs, 1);
      expect(find.byType(MobileDataBanner), findsNothing);
      unawaited(sync.dispose());
    });

    testWidgets('Without files syncs, and the Sync card says the files wait', (
      tester,
    ) async {
      final (sync, _) = await showPhone(tester);

      await tester.tap(find.text('Without files'));
      await tester.pumpAndSettle();
      expect(syncs, 1);
      expect(find.byType(MobileDataBanner), findsNothing);
      expect(find.text('Files wait for Wi-Fi'), findsOneWidget);
      unawaited(sync.dispose());
    });

    testWidgets('the Sync card chooses what goes unasked; Sync everything '
        "syncs and doesn't ask", (tester) async {
      final (sync, gate) = await showPhone(tester);
      expect(find.text('Ask first'), findsOneWidget);

      await tester.tap(find.text('Ask first'));
      await tester.pumpAndSettle();
      await tester.tap(find.text('Sync everything').last);
      await tester.pumpAndSettle();
      expect(gate.mobileData, MobileData.everything);
      expect(syncs, 1);
      expect(find.byType(MobileDataBanner), findsNothing);
      unawaited(sync.dispose());
    });

    testWidgets('a desktop shows no banner and no choice', (tester) async {
      network.state = FakeNetworkWatch.wifi;
      final (sync, _) = await showPhone(tester, offered: false);
      expect(find.byType(MobileDataBanner), findsNothing);
      expect(find.text('On mobile data'), findsNothing);
      expect(syncs, 1);
      unawaited(sync.dispose());
    });
  });
}