import 'dart:async';

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

import 'package:worker/app.dart';
import 'package:worker/core/database/hive_initializer.dart';

/// Main entry point of the Worker Mobile App
///
/// Initializes core dependencies:
/// - Hive database with adapters and boxes
/// - SharedPreferences for simple key-value storage
/// - Riverpod ProviderScope for state management
/// - Error handling boundaries
/// - System UI customization
void main() async {
  // Ensure Flutter is initialized before async operations
  WidgetsFlutterBinding.ensureInitialized();

  // Set preferred device orientations
  await SystemChrome.setPreferredOrientations([
    DeviceOrientation.portraitUp,
    DeviceOrientation.portraitDown,
  ]);

  // Initialize app with error handling
  await _initializeApp();
}

/// Initialize all app dependencies with comprehensive error handling
Future<void> _initializeApp() async {
  // Set up error handlers before anything else
  _setupErrorHandlers();

  try {
    // Initialize core dependencies in parallel for faster startup
    await Future.wait([
      _initializeHive(),
      _initializeSharedPreferences(),
    ]);

    // Run the app with Riverpod ProviderScope
    runApp(
      const ProviderScope(
        child: WorkerApp(),
      ),
    );
  } catch (error, stackTrace) {
    // Critical initialization error - show error screen
    debugPrint('Failed to initialize app: $error');
    debugPrint('StackTrace: $stackTrace');

    // Run minimal error app
    runApp(_buildErrorApp(error, stackTrace));
  }
}

/// Initialize Hive database
///
/// Sets up local database with:
/// - Type adapters for all models
/// - All required boxes (user, cart, products, etc.)
/// - Cache cleanup for expired data
/// - Encryption for sensitive data (in production)
Future<void> _initializeHive() async {
  try {
    debugPrint('Initializing Hive database...');

    await HiveInitializer.initialize(
      enableEncryption: kReleaseMode, // Enable encryption in release builds
      verbose: kDebugMode, // Verbose logging in debug mode
    );

    debugPrint('Hive database initialized successfully');
  } catch (error, stackTrace) {
    debugPrint('Failed to initialize Hive: $error');
    debugPrint('StackTrace: $stackTrace');
    rethrow;
  }
}

/// Initialize SharedPreferences
///
/// Used for simple key-value storage like:
/// - Last sync timestamp
/// - User preferences (language, theme)
/// - App settings
/// - Feature flags
Future<void> _initializeSharedPreferences() async {
  try {
    debugPrint('Initializing SharedPreferences...');

    // Pre-initialize SharedPreferences instance
    await SharedPreferences.getInstance();

    debugPrint('SharedPreferences initialized successfully');
  } catch (error, stackTrace) {
    debugPrint('Failed to initialize SharedPreferences: $error');
    debugPrint('StackTrace: $stackTrace');
    rethrow;
  }
}

/// Set up global error handlers
///
/// Captures and logs all Flutter framework errors and uncaught exceptions
void _setupErrorHandlers() {
  // Handle Flutter framework errors
  FlutterError.onError = (FlutterErrorDetails details) {
    FlutterError.presentError(details);

    // Log to console in debug mode
    if (kDebugMode) {
      debugPrint('Flutter Error: ${details.exceptionAsString()}');
      debugPrint('StackTrace: ${details.stack}');
    }

    // In production, you would send to crash analytics service
    // Example: FirebaseCrashlytics.instance.recordFlutterError(details);
  };

  // Handle errors outside of Flutter framework
  PlatformDispatcher.instance.onError = (error, stackTrace) {
    if (kDebugMode) {
      debugPrint('Platform Error: $error');
      debugPrint('StackTrace: $stackTrace');
    }

    // In production, you would send to crash analytics service
    // Example: FirebaseCrashlytics.instance.recordError(error, stackTrace);

    return true; // Return true to indicate error was handled
  };

  // Handle zone errors (async errors not caught by Flutter)
  runZonedGuarded(
    () {
      // App will run in this zone
    },
    (error, stackTrace) {
      if (kDebugMode) {
        debugPrint('Zone Error: $error');
        debugPrint('StackTrace: $stackTrace');
      }

      // In production, you would send to crash analytics service
      // Example: FirebaseCrashlytics.instance.recordError(error, stackTrace);
    },
  );
}

/// Build minimal error app when initialization fails
///
/// Shows a user-friendly error screen instead of crashing
Widget _buildErrorApp(Object error, StackTrace stackTrace) {
  return MaterialApp(
    debugShowCheckedModeBanner: false,
    home: Scaffold(
      backgroundColor: const Color(0xFFF5F5F5),
      body: SafeArea(
        child: Center(
          child: Padding(
            padding: const EdgeInsets.all(24.0),
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                // Error icon
                const Icon(
                  Icons.error_outline,
                  size: 80,
                  color: Color(0xFFDC3545),
                ),
                const SizedBox(height: 24),

                // Error title
                const Text(
                  'Không thể khởi động ứng dụng',
                  style: TextStyle(
                    fontSize: 24,
                    fontWeight: FontWeight.bold,
                    color: Color(0xFF212529),
                  ),
                  textAlign: TextAlign.center,
                ),
                const SizedBox(height: 16),

                // Error message
                const Text(
                  'Đã xảy ra lỗi khi khởi động ứng dụng. '
                  'Vui lòng thử lại sau hoặc liên hệ hỗ trợ.',
                  style: TextStyle(
                    fontSize: 16,
                    color: Color(0xFF6C757D),
                  ),
                  textAlign: TextAlign.center,
                ),
                const SizedBox(height: 32),

                // Error details (debug mode only)
                if (kDebugMode) ...[
                  Container(
                    padding: const EdgeInsets.all(16),
                    decoration: BoxDecoration(
                      color: const Color(0xFFFFF3CD),
                      borderRadius: BorderRadius.circular(8),
                      border: Border.all(
                        color: const Color(0xFFFFECB5),
                        width: 1,
                      ),
                    ),
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        const Text(
                          'Debug Information:',
                          style: TextStyle(
                            fontWeight: FontWeight.bold,
                            color: Color(0xFF856404),
                          ),
                        ),
                        const SizedBox(height: 8),
                        Text(
                          error.toString(),
                          style: const TextStyle(
                            fontSize: 12,
                            color: Color(0xFF856404),
                            fontFamily: 'monospace',
                          ),
                        ),
                      ],
                    ),
                  ),
                  const SizedBox(height: 16),
                ],

                // Restart button
                ElevatedButton.icon(
                  onPressed: () {
                    // Restart app
                    _initializeApp();
                  },
                  icon: const Icon(Icons.refresh),
                  label: const Text('Thử lại'),
                  style: ElevatedButton.styleFrom(
                    backgroundColor: const Color(0xFF005B9A),
                    foregroundColor: Colors.white,
                    padding: const EdgeInsets.symmetric(
                      horizontal: 32,
                      vertical: 16,
                    ),
                    shape: RoundedRectangleBorder(
                      borderRadius: BorderRadius.circular(8),
                    ),
                  ),
                ),
              ],
            ),
          ),
        ),
      ),
    ),
  );
}