nearle_pos/lib/main.dart

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import 'app/app.dart';
import 'core/services/sound_service.dart';
import 'core/theme/app_colors.dart';
import 'core/theme/app_dimens.dart';
import 'data/datasources/local_store.dart';

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();

  await _configureChrome();

  // Startup work must never be able to prevent runApp from being reached.
  // Awaiting it unguarded means one thrown exception leaves a blank window
  // with nothing on screen to explain why.
  try {
    // Opens SQLite and loads the catalogue into memory. Bills written on a
    // previous run are still on disk and still counted as unsynced.
    await LocalStore.instance.init();
    await SoundService.instance.preload();
  } catch (error, stack) {
    debugPrint('Startup failed: $error\n$stack');
    runApp(_StartupFailureApp(error: error));
    return;
  }

  runApp(const ProviderScope(child: NearlePosApp()));
}

/// Locks the terminal into landscape and hides the system bars.
///
/// Both calls are Android/iOS only. On desktop the window manager owns sizing
/// and chrome, so we skip them — invoking them there is at best a no-op and can
/// raise a MissingPluginException on some engine builds.
Future<void> _configureChrome() async {
  final isMobile = defaultTargetPlatform == TargetPlatform.android ||
      defaultTargetPlatform == TargetPlatform.iOS;
  if (kIsWeb || !isMobile) return;

  await SystemChrome.setPreferredOrientations([
    DeviceOrientation.landscapeLeft,
    DeviceOrientation.landscapeRight,
  ]);

  await SystemChrome.setEnabledSystemUIMode(SystemUiMode.immersiveSticky);
}

/// Shown when the terminal cannot start.
///
/// A cashier staring at a white window has nothing to report to support, so
/// the failure is put on screen verbatim.
class _StartupFailureApp extends StatelessWidget {
  const _StartupFailureApp({required this.error});

  final Object error;

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        backgroundColor: AppColors.background,
        body: Center(
          child: SingleChildScrollView(
            padding: const EdgeInsets.all(AppSpacing.xxl),
            child: ConstrainedBox(
              constraints: const BoxConstraints(maxWidth: 560),
              child: Column(
                mainAxisSize: MainAxisSize.min,
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Container(
                    width: 56,
                    height: 56,
                    decoration: const BoxDecoration(
                      color: AppColors.dangerSurface,
                      borderRadius: AppRadius.brMd,
                    ),
                    child: const Icon(Icons.error_outline_rounded,
                        color: AppColors.danger, size: 28,),
                  ),
                  const SizedBox(height: AppSpacing.xl),
                  const Text(
                    'Nearle POS could not start',
                    style: TextStyle(
                      fontSize: 22,
                      fontWeight: FontWeight.w700,
                      color: AppColors.textPrimary,
                    ),
                  ),
                  const SizedBox(height: AppSpacing.sm),
                  const Text(
                    'The terminal failed while opening its local database.',
                    style: TextStyle(
                      fontSize: 14,
                      color: AppColors.textSecondary,
                      height: 1.5,
                    ),
                  ),
                  const SizedBox(height: AppSpacing.xl),
                  Container(
                    width: double.infinity,
                    padding: const EdgeInsets.all(AppSpacing.lg),
                    decoration: BoxDecoration(
                      color: AppColors.surface,
                      borderRadius: AppRadius.brMd,
                      border: Border.all(color: AppColors.border),
                    ),
                    child: SelectableText(
                      '$error',
                      style: const TextStyle(
                        fontSize: 12.5,
                        height: 1.6,
                        fontFamily: 'monospace',
                        color: AppColors.textPrimary,
                      ),
                    ),
                  ),
                ],
              ),
            ),
          ),
        ),
      ),
    );
  }
}