import 'package:flutter/material.dart';

void main() {
  runApp(const UtoManagerApp());
}

/// The root application widget for the UTO Manager.
///
/// This is the entry point for the Flutter application. The full application
/// shell (three-pane layout, canvas engine, state management) will be
/// implemented in Phase 3.
class UtoManagerApp extends StatelessWidget {
  const UtoManagerApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'UTO Manager',
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(
          seedColor: const Color(0xFF1B3A6B), // Army blue
          brightness: Brightness.dark,
        ),
        useMaterial3: true,
      ),
      home: const _PlaceholderScaffold(),
    );
  }
}

/// Placeholder scaffold displayed during Phase 1 development.
///
/// Will be replaced by the full three-pane UI shell in Phase 3.
class _PlaceholderScaffold extends StatelessWidget {
  const _PlaceholderScaffold();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('UTO Manager'),
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
      ),
      body: const Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(Icons.military_tech, size: 64),
            SizedBox(height: 16),
            Text(
              'Unit Task Organization Manager',
              style: TextStyle(fontSize: 24, fontWeight: FontWeight.bold),
            ),
            SizedBox(height: 8),
            Text(
              'U.S. Army 2026 Doctrine — '
              'Phase 1: Architecture & Data Foundations',
              textAlign: TextAlign.center,
            ),
            SizedBox(height: 24),
            Text(
              'Canvas engine and UI shell coming in Phase 2 & 3.',
              style: TextStyle(color: Colors.grey),
            ),
          ],
        ),
      ),
    );
  }
}