import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:provider/provider.dart';

import 'package:fuel_tax_tracker/models/vehicle.dart';
import 'package:fuel_tax_tracker/screens/add_edit_vehicle_screen.dart';
import 'package:fuel_tax_tracker/screens/vehicle_detail_screen.dart';
import 'package:fuel_tax_tracker/services/app_state.dart';

/// Covers the "VIN already belongs to another vehicle" dialog on the Add
/// Vehicle form — [AddEditVehicleScreen] driven directly against an
/// [AppState] whose in-memory `vehicles` list is seeded by hand (no
/// database/cloud wiring needed, since the dialog only reads
/// [AppState.vehicleByVin]).
void main() {
  final existingVehicle = Vehicle(
    id: 'existing-id',
    vin: '1FMPU18L1TLB51349',
    nickname: 'Red Truck',
    updatedAt: DateTime.utc(2026, 1, 1),
  );

  Future<AppState> pumpAddVehicleScreen(WidgetTester tester) async {
    final appState = AppState()
      ..isLoading = false
      ..vehicles = [existingVehicle];

    await tester.pumpWidget(
      ChangeNotifierProvider.value(
        value: appState,
        child: const MaterialApp(home: AddEditVehicleScreen()),
      ),
    );
    return appState;
  }

  testWidgets('entering a VIN that already exists shows the dialog', (tester) async {
    await pumpAddVehicleScreen(tester);

    await tester.enterText(find.widgetWithText(TextFormField, 'VIN *'), existingVehicle.vin);
    await tester.pumpAndSettle();

    expect(find.text('Vehicle already exists'), findsOneWidget);
    expect(
      find.text(
        'Vehicle with the VIN ${existingVehicle.vin} already exists, would you like to open that vehicle?',
      ),
      findsOneWidget,
    );
  });

  testWidgets('tapping No dismisses the dialog and stays on the create screen', (tester) async {
    await pumpAddVehicleScreen(tester);

    await tester.enterText(find.widgetWithText(TextFormField, 'VIN *'), existingVehicle.vin);
    await tester.pumpAndSettle();

    await tester.tap(find.widgetWithText(TextButton, 'No'));
    await tester.pumpAndSettle();

    expect(find.text('Vehicle already exists'), findsNothing);
    expect(find.text('Add Vehicle'), findsWidgets);
    expect(
      find.text('A vehicle with VIN "${existingVehicle.vin}" already exists.'),
      findsOneWidget,
      reason: 'the field itself should be flagged invalid after declining to open the existing vehicle',
    );
  });

  testWidgets('tapping Yes opens the existing vehicle', (tester) async {
    await pumpAddVehicleScreen(tester);

    await tester.enterText(find.widgetWithText(TextFormField, 'VIN *'), existingVehicle.vin);
    await tester.pumpAndSettle();

    await tester.tap(find.widgetWithText(TextButton, 'Yes'));
    await tester.pumpAndSettle();

    expect(find.byType(VehicleDetailScreen), findsOneWidget);
    expect(find.text(existingVehicle.displayLabel), findsOneWidget);
    expect(find.byType(AddEditVehicleScreen), findsNothing,
        reason: 'the create screen should be popped, not left underneath');
  });

  testWidgets('editing a vehicle with its own VIN does not trigger the dialog', (tester) async {
    final appState = AppState()
      ..isLoading = false
      ..vehicles = [existingVehicle];

    await tester.pumpWidget(
      ChangeNotifierProvider.value(
        value: appState,
        child: MaterialApp(home: AddEditVehicleScreen(vehicle: existingVehicle)),
      ),
    );

    // The field already starts pre-filled with its own VIN; nudge it to
    // fire onChanged the same way a real edit would.
    await tester.enterText(find.widgetWithText(TextFormField, 'VIN *'), existingVehicle.vin);
    await tester.pumpAndSettle();

    expect(find.text('Vehicle already exists'), findsNothing);
  });
}