import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:google_fonts/google_fonts.dart';
import 'package:nearle_pos/app/app.dart';
import 'package:nearle_pos/data/datasources/local_store.dart';
import 'package:nearle_pos/data/datasources/seed_data.dart';
import 'package:nearle_pos/data/remote/pos_auth_api.dart';
import 'package:nearle_pos/domain/entities/pos_session.dart';
import 'package:nearle_pos/app/providers.dart';
import 'package:nearle_pos/domain/entities/shift_report.dart';
import 'package:nearle_pos/domain/entities/store_account.dart';
import 'package:nearle_pos/presentation/pos/providers/cart_controller.dart';
import 'package:nearle_pos/presentation/pos/screens/pos_dashboard_screen.dart';
import 'package:nearle_pos/presentation/sync/providers/sync_controller.dart';

/// Boots the real application widget.
///
/// The unit suite proves the money is right; this proves the thing actually
/// assembles — router guard, provider graph, theme and shell — which type
/// checking alone cannot tell you.
void main() {
  setUpAll(() {
    // Tests have no network, and an attempted font fetch throws.
    GoogleFonts.config.allowRuntimeFetching = false;
    LocalStore.registerSeed(
      products: SeedData.products,
      customers: SeedData.customers,
    );
  });

  setUp(() async {
    await LocalStore.instance.reset(withCatalogue: true);
  });

  const testStore = StoreAccount(
    id: 'store-001',
    name: 'Nearle Daily',
    email: 'manager@ragulstores.test',
    address: '1 Test Street',
    gstin: '33AABCU9603R1ZM',
    phone: '9840000000',
    staff: [
      StaffUser(id: 'u1', name: 'Suriya', role: StaffRole.admin),
    ],
  );

  ShiftReport blankReport() => ShiftReport.blank(
        businessDate: DateTime(2026, 7, 31),
        terminalId: 'TERM-01',
        cashierName: 'Suriya',
      );

  Future<void> bootApp(WidgetTester tester, {bool supervisor = true}) async {
    await tester.pumpWidget(
      ProviderScope(
        overrides: [
          // The background drain would open a broker connection and hit the
          // disk on a clock this test controls. Neither is what these tests
          // measure, and a half-driven timer would leak into the next one.
          syncBootstrapProvider.overrideWith((ref) async {}),

          // Sign-in now reads staff and store details from SQLite. Real disk
          // I/O cannot complete inside a fixed number of pumps on a fake
          // clock, so the sign-in would hang and every later assertion would
          // fail on a screen that never arrived.
          storeAccountProvider.overrideWith((ref) async => testStore),

          // Sign-in is a network call now — a person's own back-office account
          // rather than two constants compiled into the build. A widget test
          // must not depend on a live endpoint, so the client is swapped for
          // one that answers with a fixed session.
          posAuthApiProvider.overrideWithValue(
            _FakePosAuthApi(canManageStaff: supervisor),
          ),

          // Catalogue reads come from the in-memory cache and resolve on the
          // spot, but these four go to SQLite. Real disk I/O cannot be driven
          // by the fake clock a widget test runs on: sqflite's own lock-warning
          // timer is left pending and trips the binding's leak check. Stubbed
          // so this test measures rendering, which is what it is for.
          unsyncedCountProvider.overrideWith((ref) async => 0),
          promosProvider.overrideWith((ref) async => []),
          activePromosProvider.overrideWith((ref) async => []),
          parkedBillsProvider.overrideWith((ref) async => []),
          orderSyncRowsProvider.overrideWith((ref) async => []),
          todayReportProvider.overrideWith((ref) async => blankReport()),
          myShiftReportProvider.overrideWith((ref) async => blankReport()),
        ],
        child: const NearlePosApp(),
      ),
    );
    await tester.pumpAndSettle();
  }

  /// Pumps a fixed number of frames instead of settling.
  ///
  /// Once past login the header subscribes to a periodic clock, so there is
  /// always another frame pending and `pumpAndSettle` never returns.
  Future<void> settle(WidgetTester tester, {int frames = 15}) async {
    for (var i = 0; i < frames; i++) {
      await tester.pump(const Duration(milliseconds: 100));
    }
  }

  Future<void> signIn(WidgetTester tester) async {
    final fields = find.byType(TextFormField);
    await tester.enterText(fields.first, _testEmail);
    await tester.enterText(fields.at(1), _testPassword);
    await tester.pump();

    // Sign-in reaches SQLite now: it writes the outlet the back office named
    // and the store details a receipt is legally required to carry, before the
    // shell opens. Real disk I/O cannot complete on a widget test's fake clock,
    // so the tap runs inside runAsync — pumping alone leaves the sign-in
    // suspended for ever and every later assertion fails on a screen that never
    // arrived.
    await tester.runAsync(() async {
      await tester.tap(find.text('Sign in').last);
      await Future<void>.delayed(const Duration(milliseconds: 200));
    });
    await settle(tester);
  }

  testWidgets('the terminal starts on the login screen', (tester) async {
    await bootApp(tester);

    expect(find.byType(TextFormField), findsWidgets);
    expect(find.text('Sign in'), findsWidgets);
    expect(tester.takeException(), isNull);
  });

  testWidgets('the auth guard keeps an unauthenticated terminal out',
      (tester) async {
    await bootApp(tester);

    expect(find.byType(PosDashboardScreen), findsNothing);
  });

  testWidgets('signing in reaches the billing terminal', (tester) async {
    await bootApp(tester);
    await signIn(tester);

    expect(find.byType(PosDashboardScreen), findsOneWidget);
    expect(tester.takeException(), isNull);
  });

  testWidgets('the shell renders every module without throwing',
      (tester) async {
    // Wide enough that the sidebar shows labels and the bill stays docked —
    // the layout where a button label and its total compete for width.
    tester.view.physicalSize = const Size(1800, 1200);
    tester.view.devicePixelRatio = 1;
    addTearDown(tester.view.reset);

    await bootApp(tester);
    await signIn(tester);

    for (final label in [
      'Customers',
      'Product Import',
      'Promo',
      'Events',
      'Settings',
      'POS',
    ]) {
      final target = find.text(label);
      expect(target, findsWidgets, reason: 'no sidebar entry for "$label"');

      await tester.tap(target.first);
      await settle(tester);

      // Settings builds a printer-settings controller that reads six values
      // out of SQLite, and sqflite arms a ten-second lock-warning timer around
      // each. Those reads cannot complete on a fake clock, so the timer would
      // still be pending at teardown and the binding would fail the test for
      // that rather than for anything it is about. Pumping past the ten
      // seconds lets the timer fire and clear.
      await tester.pump(const Duration(seconds: 11));
      expect(tester.takeException(), isNull, reason: 'opening "$label" threw');
    }
  });

  testWidgets('a cashier session gets billing and nothing else',
      (tester) async {
    // The other half of the role split, and the half worth pinning: the shell
    // a person gets is decided by the back office, not by which tab they
    // picked on the way in. Same credentials, same screen size, same boot —
    // the only difference is `can_manage_staff` on the session, and the
    // back-office modules have to be unreachable because of it.
    tester.view.physicalSize = const Size(1800, 1200);
    tester.view.devicePixelRatio = 1;
    addTearDown(tester.view.reset);

    await bootApp(tester, supervisor: false);
    await signIn(tester);

    // Signed in, and on the billing screen.
    expect(find.byType(PosDashboardScreen), findsOneWidget);

    // These labels exist only in the sidebar, so their absence is the whole
    // claim: a cashier cannot reach the catalogue, the promos or the
    // terminal's configuration.
    for (final label in ['Product Import', 'Promo', 'Settings']) {
      expect(
        find.text(label),
        findsNothing,
        reason: 'a cashier must not be offered "$label"',
      );
    }

    expect(tester.takeException(), isNull);
  });

  testWidgets('the back office connection dialog opens and validates',
      (tester) async {
    // The only way a shop can point a till at a broker. Until it existed a
    // store was wired up by editing a provider and rebuilding.
    tester.view.physicalSize = const Size(1800, 1200);
    tester.view.devicePixelRatio = 1;
    addTearDown(tester.view.reset);

    await bootApp(tester);
    await signIn(tester);

    await tester.tap(find.text('Settings').first);
    await settle(tester);

    // Clears sqflite's lock-warning timer — see the module loop above.
    await tester.pump(const Duration(seconds: 11));

    await tester.tap(find.text('Configure').first);
    await settle(tester);

    // "Back office connection" is both the dialog title and the About card's
    // button, so match the dialog itself.
    expect(find.byType(AlertDialog), findsOneWidget);
    expect(find.text('MQTT'), findsOneWidget);

    // Switching to MQTT and saving with no host must be refused, not silently
    // accepted — a terminal pointed at nothing looks identical to one that is
    // simply offline.
    await tester.tap(find.text('MQTT'));
    await settle(tester);
    await tester.tap(find.text('Save'));
    await settle(tester);

    expect(find.text('A broker host is required'), findsOneWidget);
    expect(find.byType(AlertDialog), findsOneWidget,
        reason: 'the dialog must stay open on a validation failure',);
    expect(tester.takeException(), isNull);
  });
}

const _testEmail = 'manager@ragulstores.test';
const _testPassword = 'correct-horse';

/// A back office that accepts one account and refuses everything else.
///
/// Subclasses rather than reimplements an interface because the real client is
/// concrete — and answering a wrong password correctly matters here: the login
/// screen's failure path is part of what these tests cover.
class _FakePosAuthApi extends PosAuthApi {
  _FakePosAuthApi({this.canManageStaff = true})
      : super(baseUrl: 'https://example.invalid/pos');

  /// Which shell the back office says this account gets. A supervisor by
  /// default, because most of these tests are about the full shell rendering.
  final bool canManageStaff;

  @override
  Future<PosSession> login({
    required String authname,
    required String password,
    String? terminalId,
    String? deviceId,
    int? locationId,
    int? configId,
  }) async {
    if (authname.trim() != _testEmail || password != _testPassword) {
      throw const PosAuthException(
        'those sign-in details were not recognised',
        isCredentialFailure: true,
      );
    }

    return PosSession(
      token: 'test-session-token',
      expiresAt: DateTime.now().add(const Duration(days: 30)),
      userId: 1229,
      fullName: 'Test Manager',
      email: _testEmail,
      roleId: canManageStaff ? 7 : 8,
      role: canManageStaff ? 'Supervisor' : 'Cashier',
      canManageStaff: canManageStaff,
      tenantId: 1087,
      tenantName: 'Ragul Stores',
      storeId: '1135',
      locationId: 1135,
      locationName: 'Ragul stores Selvapuram',
      outlets: const [
        PosOutlet(locationId: 1135, locationName: 'Ragul stores Selvapuram'),
      ],
    );
  }

  @override
  void dispose() {}
}