import 'dart:async';
import 'dart:io';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_localizations/flutter_localizations.dart';
import 'package:flutter_quill/flutter_quill.dart';
import 'package:notas/data/app_database.dart';
import 'package:notas/data/api_client.dart';
import 'package:notas/data/local_vault_service.dart';
import 'package:notas/data/note_repository.dart';
import 'package:notas/platform/app_platform.dart';
import 'package:notas/platform/window_state.dart';
import 'package:notas/screens/biometric_choice_screen.dart';
import 'package:notas/screens/biometric_gate_screen.dart';
import 'package:notas/screens/home_screen.dart';
import 'package:notas/screens/settings_screen.dart';
import 'package:notas/screens/vault_access_screen.dart';
import 'package:notas/theme/app_palette.dart';
import 'package:notas/theme/app_theme.dart';
import 'package:notas/widgets/sync_status.dart';
import 'package:path/path.dart' as p;
import 'package:path_provider/path_provider.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:window_manager/window_manager.dart';

enum _AppSection { home, settings }

enum _AppPhase { loading, access, biometricChoice, biometricGate, notes }

class PerformSyncIntent extends Intent {
  const PerformSyncIntent();
}

class NotesApp extends StatefulWidget {
  const NotesApp({super.key});

  @override
  State<NotesApp> createState() => _NotesAppState();
}

class _NotesAppState extends State<NotesApp>
    with WindowListener, WidgetsBindingObserver {
  static const Duration _screenTransitionDuration = Duration(milliseconds: 280);
  static const Duration _biometricInactivityTimeout = Duration(minutes: 5);
  static const Duration _syncInterval = Duration(minutes: 5);
  static const Duration _windowSizeSaveDelay = Duration(milliseconds: 350);
  static const String _themeSeedColorKey = 'theme_seed_color_v1';
  static const String _themeModeKey = 'theme_mode_v1';

  final LocalVaultService _vaultService = LocalVaultService.instance;
  final GlobalKey<ScaffoldMessengerState> _scaffoldMessengerKey =
      GlobalKey<ScaffoldMessengerState>();
  final GlobalKey<NavigatorState> _navigatorKey = GlobalKey<NavigatorState>();

  AppDatabase? _database;
  NoteRepository? _repository;
  String? _pendingEncryptionKey;
  bool _isBootstrapping = true;
  bool _isUnlocking = false;
  bool _biometricGateEnabled = false;
  int _biometricGateSession = 0;
  Timer? _biometricLockTimer;
  Timer? _windowSizeSaveTimer;
  Timer? _syncTimer;
  bool _isHandlingWindowClose = false;
  _AppPhase _phase = _AppPhase.loading;
  _AppSection _currentSection = _AppSection.home;
  SyncStatus _syncStatus = SyncStatus.idle;
  double? _syncProgress;
  String? _syncDetailMessage;
  String? _syncErrorMessage;
  int _syncOperationId = 0;
  int _homeRefreshToken = 0;
  Color _themeSeedColor = Colors.amber;
  ThemeMode _themeMode = ThemeMode.system;

  // Cached ThemeData for light and dark variants.
  ThemeData? _lightTheme;
  ThemeData? _darkTheme;

  bool _isSyncBannerVisible() {
    switch (_syncStatus) {
      case SyncStatus.preparing:
      case SyncStatus.encrypting:
      case SyncStatus.uploading:
      case SyncStatus.waitingResponse:
      case SyncStatus.decrypting:
      case SyncStatus.syncing:
      case SyncStatus.synced:
      case SyncStatus.error:
        return true;
      case SyncStatus.idle:
        return false;
    }
  }

  Widget _buildSyncBanner(BuildContext context) {
    if (!_isSyncBannerVisible()) {
      return const SizedBox.shrink();
    }

    final AppPalette palette = _activePalette();
    final String message =
        _syncErrorMessage ?? _syncDetailMessage ?? 'Sincronizando...';
    final double? progress = _syncProgress;
    final IconData icon;
    final Color accentColor;

    switch (_syncStatus) {
      case SyncStatus.preparing:
      case SyncStatus.encrypting:
      case SyncStatus.uploading:
      case SyncStatus.waitingResponse:
      case SyncStatus.decrypting:
      case SyncStatus.syncing:
        icon = Icons.cloud_sync_outlined;
        accentColor = palette.textSecondary;
        break;
      case SyncStatus.synced:
        icon = Icons.check_circle;
        accentColor = palette.success;
        break;
      case SyncStatus.error:
        icon = Icons.error;
        accentColor = palette.destructiveAccent;
        break;
      case SyncStatus.idle:
        icon = Icons.cloud_sync_outlined;
        accentColor = palette.textSecondary;
        break;
    }

    return Material(
      color: palette.surfaceElevated,
      elevation: 12,
      child: SafeArea(
        top: false,
        child: Container(
          padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 10),
          decoration: BoxDecoration(
            border: Border(
              top: BorderSide(color: accentColor.withValues(alpha: 0.45)),
            ),
          ),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: [
              Row(
                children: [
                  Icon(icon, color: accentColor, size: 18),
                  const SizedBox(width: 10),
                  Expanded(
                    child: Text(
                      message,
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                      style: TextStyle(
                        color: palette.textPrimary,
                        fontSize: 13,
                        fontWeight: FontWeight.w600,
                      ),
                    ),
                  ),
                ],
              ),
              if (_syncStatus == SyncStatus.preparing ||
                  _syncStatus == SyncStatus.encrypting ||
                  _syncStatus == SyncStatus.uploading ||
                  _syncStatus == SyncStatus.waitingResponse ||
                  _syncStatus == SyncStatus.decrypting ||
                  _syncStatus == SyncStatus.syncing) ...[
                const SizedBox(height: 8),
                ClipRRect(
                  borderRadius: BorderRadius.circular(999),
                  child: LinearProgressIndicator(
                    minHeight: 4,
                    value: progress,
                    backgroundColor: palette.borderMuted,
                  ),
                ),
              ],
            ],
          ),
        ),
      ),
    );
  }

  Brightness _effectiveBrightness() {
    switch (_themeMode) {
      case ThemeMode.dark:
        return Brightness.dark;
      case ThemeMode.light:
        return Brightness.light;
      case ThemeMode.system:
        return WidgetsBinding.instance.platformDispatcher.platformBrightness;
    }
  }

  AppPalette _activePalette() {
    return AppPalette.fromBrightness(
      _effectiveBrightness(),
      seedColor: _themeSeedColor,
    );
  }

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
    if (isDesktop) {
      windowManager.addListener(this);
      windowManager.setPreventClose(true);
    }
    _loadThemeSeedColor();
    _loadThemeMode();
    _bootstrapVault();
  }

  @override
  void dispose() {
    WidgetsBinding.instance.removeObserver(this);
    if (isDesktop) {
      windowManager.removeListener(this);
      windowManager.setPreventClose(false);
    }
    _biometricLockTimer?.cancel();
    _windowSizeSaveTimer?.cancel();
    _syncTimer?.cancel();
    _database?.close();
    super.dispose();
  }

  Future<void> _loadThemeSeedColor() async {
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    final int? storedColorValue = prefs.getInt(_themeSeedColorKey);
    if (storedColorValue == null || !mounted) {
      return;
    }

    setState(() {
      _themeSeedColor = Color(storedColorValue);
      _updateThemeData();
    });
  }

  Future<void> _setThemeSeedColor(Color color) async {
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    await prefs.setInt(_themeSeedColorKey, color.toARGB32());

    if (!mounted) {
      return;
    }

    setState(() {
      _themeSeedColor = color;
      _updateThemeData();
    });
  }

  Future<void> _loadThemeMode() async {
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    final int? stored = prefs.getInt(_themeModeKey);
    if (!mounted) return;

    setState(() {
      if (stored == null) {
        _themeMode = ThemeMode.system;
      } else if (stored == 1) {
        _themeMode = ThemeMode.light;
      } else if (stored == 2) {
        _themeMode = ThemeMode.dark;
      } else {
        _themeMode = ThemeMode.system;
      }
      _updateThemeData();
    });
  }

  Future<void> _setThemeMode(ThemeMode mode) async {
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    final int stored = mode == ThemeMode.system
        ? 0
        : (mode == ThemeMode.light ? 1 : 2);
    await prefs.setInt(_themeModeKey, stored);

    if (!mounted) return;

    setState(() {
      _themeMode = mode;
    });
  }

  void _updateThemeData() {
    _lightTheme = AppTheme.theme(
      seedColor: _themeSeedColor,
      brightness: Brightness.light,
    );
    _darkTheme = AppTheme.theme(
      seedColor: _themeSeedColor,
      brightness: Brightness.dark,
    );
    // Updated light/dark themes regenerated
  }

  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    if (_isUnlocking) {
      return;
    }

    switch (state) {
      case AppLifecycleState.resumed:
        _cancelBiometricLockTimer();
        return;
      case AppLifecycleState.inactive:
      case AppLifecycleState.paused:
        _scheduleBiometricLockTimer();
        return;
      case AppLifecycleState.detached:
      case AppLifecycleState.hidden:
        return;
    }
  }

  Future<void> _bootstrapVault() async {
    try {
      final bool hasEncryptionKey = await _vaultService.hasEncryptionKey();
      _biometricGateEnabled =
          hasEncryptionKey && await _vaultService.isBiometricGateEnabled();

      if (!hasEncryptionKey) {
        _pendingEncryptionKey = null;
        if (mounted) {
          setState(() {
            _phase = _AppPhase.access;
          });
        }
        return;
      }

      final bool accessCompleted = await _vaultService.isVaultAccessCompleted();
      final bool biometricChoicePending = await _vaultService
          .isBiometricChoicePending();

      if (!accessCompleted) {
        _pendingEncryptionKey = await _vaultService
            .readStoredEncryptionKeyRaw();
        if (mounted) {
          setState(() {
            _phase = _AppPhase.access;
          });
        }
        return;
      }

      if (biometricChoicePending) {
        _pendingEncryptionKey = await _vaultService
            .readStoredEncryptionKeyRaw();
        if (mounted) {
          setState(() {
            _phase = _AppPhase.biometricChoice;
          });
        }
        return;
      }

      if (_biometricGateEnabled) {
        if (mounted) {
          setState(() {
            _phase = _AppPhase.biometricGate;
          });
        }
        return;
      }

      final String? encryptionKey = await _vaultService
          .readStoredEncryptionKeyRaw();
      if (encryptionKey != null) {
        await _openVault(encryptionKey);
      } else if (mounted) {
        setState(() {
          _phase = _AppPhase.access;
        });
      }
    } finally {
      if (mounted) {
        setState(() {
          _isBootstrapping = false;
        });
      }
    }
  }

  Future<void> _openVault(String encryptionKey) async {
    await _database?.close();

    try {
      final AppDatabase database = AppDatabase(encryptionKey: encryptionKey);
      if (!mounted) {
        await database.close();
        return;
      }

      setState(() {
        _database = database;
        _repository = NoteRepository(
          database: database,
          authApi: AuthApi.instance,
          masterKey: encryptionKey,
        );
        _phase = _AppPhase.notes;
      });

      // Start periodic sync
      _startPeriodicSync();
      // Run an initial sync immediately and let the repository use the
      // stored lastSyncAt when it exists.
      unawaited(_performSync());
    } catch (e) {
      // If the database file is not a valid SQLite DB (e.g., wrong key or corruption),
      // reset the local vault so the app doesn't crash. The reset will delete DB files
      // and clear the stored encryption key.
      await _resetLocalVaultData();

      if (mounted) {
        _scaffoldMessengerKey.currentState?.showSnackBar(
          const SnackBar(
            content: Text(
              'El vault local estaba corrupto y ha sido reiniciado.',
            ),
          ),
        );
      }
    }
  }

  Future<void> _beginInitialVaultFlow({String? actionLabel}) async {
    if (_isUnlocking) {
      return;
    }

    setState(() {
      _isUnlocking = true;
    });

    try {
      if (actionLabel != null) {
        _showAccountPlaceholder(actionLabel);
      }

      final String? existingKey = await _vaultService
          .readStoredEncryptionKeyRaw();
      final String encryptionKey =
          existingKey ?? await _vaultService.createEncryptionKey();

      _pendingEncryptionKey = encryptionKey;
      await _vaultService.setVaultAccessCompleted(true);
      await _vaultService.setBiometricChoicePending(true);
      await _vaultService.setBiometricGateEnabled(false);

      if (mounted) {
        setState(() {
          _phase = _AppPhase.biometricChoice;
          _biometricGateEnabled = false;
        });
      }
    } catch (error) {
      _scaffoldMessengerKey.currentState?.showSnackBar(
        SnackBar(content: Text('No se pudo preparar el vault local: $error')),
      );
    } finally {
      if (mounted) {
        setState(() {
          _isUnlocking = false;
          _isBootstrapping = false;
        });
      }
    }
  }

  Future<void> _beginRemoteVaultFlow({
    required String username,
    required String password,
    required bool isRegister,
  }) async {
    if (_isUnlocking) {
      return;
    }

    setState(() {
      _isUnlocking = true;
    });

    try {
      if (isRegister) {
        final String encryptionKey = _vaultService.generateEncryptionKey();
        final String encryptedMasterKey = await AuthApi.instance
            .encryptWithPassword(encryptionKey, password);

        final Map<String, dynamic> response = await AuthApi.instance.register(
          username,
          password,
          encryptedMasterKey: encryptedMasterKey,
        );

        if (response['error'] == true) {
          throw StateError('No se pudo registrar el usuario.');
        }

        await _vaultService.storeEncryptionKey(encryptionKey);
        _pendingEncryptionKey = encryptionKey;
      } else {
        final Map<String, dynamic> response = await AuthApi.instance.login(
          username,
          password,
        );

        if (response['error'] == true) {
          throw StateError('No se pudo iniciar sesión.');
        }

        final String? encryptedMasterKey =
            (response['encrypted_master_key'] as String?) ??
            (response['encryptedMasterKey'] as String?);

        if (encryptedMasterKey == null || encryptedMasterKey.isEmpty) {
          throw StateError('La API no devolvió la clave de encriptación.');
        }

        final String encryptionKey = await AuthApi.instance.decryptWithPassword(
          encryptedMasterKey,
          password,
        );

        await _vaultService.storeEncryptionKey(encryptionKey);
        _pendingEncryptionKey = encryptionKey;
      }

      await _vaultService.setVaultAccessCompleted(true);
      await _vaultService.setBiometricChoicePending(true);
      await _vaultService.setBiometricGateEnabled(false);

      if (mounted) {
        setState(() {
          _phase = _AppPhase.biometricChoice;
          _biometricGateEnabled = false;
        });
      }
    } catch (error) {
      _scaffoldMessengerKey.currentState?.showSnackBar(
        SnackBar(
          content: Text('No se pudo completar la autenticación: $error'),
        ),
      );
    } finally {
      if (mounted) {
        setState(() {
          _isUnlocking = false;
          _isBootstrapping = false;
        });
      }
    }
  }

  Future<void> _enterWithoutAccount() {
    return _beginInitialVaultFlow();
  }

  Future<void> _completeBiometricChoice({
    required bool enableBiometrics,
  }) async {
    if (_isUnlocking) {
      return;
    }

    setState(() {
      _isUnlocking = true;
    });

    try {
      final String? pendingKey =
          _pendingEncryptionKey ??
          await _vaultService.readStoredEncryptionKeyRaw();

      if (pendingKey == null) {
        throw StateError('No se encontró la llave local.');
      }

      if (enableBiometrics) {
        final bool available = await _vaultService.isBiometricAvailable();
        if (available) {
          bool activated = await _vaultService.enableBiometricProtection();
          while (!activated) {
            // Ask the user to retry or skip - pass currentContext directly in builder
            final NavigatorState? navigator = _navigatorKey.currentState;

            if (navigator == null) break;
            if (!mounted) return;

            final bool? retry = await showDialog<bool>(
              context: context,
              builder: (BuildContext dialogContext) {
                final AppPalette palette = _activePalette();
                return AlertDialog(
                  backgroundColor: palette.cardBackground,
                  shape: RoundedRectangleBorder(
                    borderRadius: BorderRadius.circular(12),
                    side: BorderSide(color: palette.border),
                  ),
                  title: const Text('No se pudo activar la biometría'),
                  content: const Text(
                    'No se pudo activar la biometría. ¿Quieres intentarlo de nuevo o entrar sin huella?',
                  ),
                  actions: [
                    TextButton(
                      onPressed: () => navigator.pop(false),
                      child: const Text('Entrar sin huella'),
                    ),
                    FilledButton(
                      onPressed: () => navigator.pop(true),
                      child: const Text('Reintentar'),
                    ),
                  ],
                );
              },
            );

            if (retry != true) {
              // User chose to skip biometric activation
              break;
            }

            activated = await _vaultService.enableBiometricProtection();
          }

          if (activated) {
            await _vaultService.setBiometricChoicePending(false);
            await _vaultService.setVaultAccessCompleted(true);
            _biometricGateEnabled = true;
            _pendingEncryptionKey = pendingKey;
            await _openVault(pendingKey);
            return;
          }
        }

        _scaffoldMessengerKey.currentState?.showSnackBar(
          const SnackBar(
            content: Text(
              'La biometría no está disponible en este dispositivo.',
            ),
          ),
        );
        return;
      }

      await _vaultService.setBiometricGateEnabled(false);
      await _vaultService.setBiometricChoicePending(false);
      await _vaultService.setVaultAccessCompleted(true);
      _biometricGateEnabled = false;
      _pendingEncryptionKey = pendingKey;
      await _openVault(pendingKey);
    } catch (error) {
      _scaffoldMessengerKey.currentState?.showSnackBar(
        SnackBar(
          content: Text(
            'No se pudo finalizar la configuración del vault: $error',
          ),
        ),
      );
    } finally {
      if (mounted) {
        setState(() {
          _isUnlocking = false;
          _isBootstrapping = false;
        });
      }
    }
  }

  Future<void> _unlockBiometricGate() async {
    if (_isUnlocking) {
      return;
    }

    setState(() {
      _isUnlocking = true;
    });

    try {
      final String? encryptionKey = await _vaultService.readEncryptionKey();

      if (encryptionKey != null) {
        await _openVault(encryptionKey);
      }
    } catch (error) {
      _scaffoldMessengerKey.currentState?.showSnackBar(
        SnackBar(content: Text('No se pudo desbloquear el vault: $error')),
      );
    } finally {
      if (mounted) {
        setState(() {
          _isUnlocking = false;
          _isBootstrapping = false;
        });
      }
    }
  }

  void _openSettings() {
    if (!mounted) {
      return;
    }

    setState(() {
      _currentSection = _AppSection.settings;
    });
  }

  void _openHome() {
    if (!mounted) {
      return;
    }

    setState(() {
      _currentSection = _AppSection.home;
    });
  }

  Future<void> _resetLocalVaultData() async {
    final AppDatabase? database = _database;

    setState(() {
      _repository = null;
      _database = null;
      _isBootstrapping = true;
      _phase = _AppPhase.loading;
    });

    await database?.close();

    await _vaultService.clearEncryptionKey();
    await AuthApi.instance.clearTokens();

    final SharedPreferences prefs = await SharedPreferences.getInstance();
    await prefs.clear();

    final Directory supportDir = await getApplicationSupportDirectory();
    final String dbPath = p.join(supportDir.path, 'notes.sqlite');
    final List<String> filesToDelete = <String>[
      dbPath,
      '$dbPath-wal',
      '$dbPath-shm',
      '$dbPath-journal',
    ];

    for (final String filePath in filesToDelete) {
      final File file = File(filePath);
      if (await file.exists()) {
        await file.delete();
      }
    }

    if (!mounted) {
      return;
    }

    setState(() {
      _isBootstrapping = false;
      _isUnlocking = false;
      _biometricGateEnabled = false;
      _pendingEncryptionKey = null;
      _phase = _AppPhase.access;
    });
  }

  Future<void> _lockVault() async {
    final AppDatabase? database = _database;

    if (database == null && _repository == null) {
      return;
    }

    await database?.close();

    if (!mounted) {
      return;
    }

    setState(() {
      _database = null;
      _repository = null;
      _isBootstrapping = false;
      _biometricGateSession += 1;
      _phase = _AppPhase.biometricGate;
      _currentSection = _AppSection.home;
    });
  }

  bool get _needsBiometricLock => _biometricGateEnabled && _repository != null;

  void _cancelBiometricLockTimer() {
    _biometricLockTimer?.cancel();
    _biometricLockTimer = null;
  }

  void _scheduleBiometricLockTimer() {
    if (!_needsBiometricLock) {
      return;
    }

    _biometricLockTimer?.cancel();
    _biometricLockTimer = Timer(_biometricInactivityTimeout, () {
      if (!mounted || !_needsBiometricLock) {
        return;
      }

      unawaited(_lockVault());
    });
  }

  Future<void> _allowWindowClose() async {
    if (!isDesktop) {
      return;
    }

    await windowManager.setPreventClose(false);
    await windowManager.close();
  }

  void _showAccountPlaceholder(String actionLabel) {
    _scaffoldMessengerKey.currentState?.showSnackBar(
      SnackBar(
        content: Text(
          '$actionLabel todavía no está conectado con la API. Usa "Entrar sin cuenta" para empezar en local.',
        ),
      ),
    );
  }

  Future<void> _saveWindowSize() async {
    if (await windowManager.isFullScreen()) {
      return;
    }

    if (await windowManager.isMaximized()) {
      return;
    }

    final Size currentSize = await windowManager.getSize();
    await WindowStateStore.instance.saveWindowSize(currentSize);
  }

  void _scheduleWindowSizeSave() {
    if (!isDesktop) {
      return;
    }

    _windowSizeSaveTimer?.cancel();
    _windowSizeSaveTimer = Timer(_windowSizeSaveDelay, () {
      _windowSizeSaveTimer = null;
      if (!mounted) {
        return;
      }

      unawaited(_saveWindowSize());
    });
  }

  void _startPeriodicSync() {
    _syncTimer?.cancel();
    _syncTimer = Timer.periodic(_syncInterval, (_) {
      _performSync();
    });
  }

  Future<void> _performSync({bool forceFull = false}) async {
    if (_repository == null) {
      return;
    }

    if (!mounted) {
      return;
    }

    if (_syncStatus == SyncStatus.preparing ||
        _syncStatus == SyncStatus.encrypting ||
        _syncStatus == SyncStatus.uploading ||
        _syncStatus == SyncStatus.waitingResponse ||
        _syncStatus == SyncStatus.decrypting ||
        _syncStatus == SyncStatus.syncing) {
      return;
    }

    final int syncOperationId = ++_syncOperationId;

    setState(() {
      _syncStatus = SyncStatus.preparing;
      _syncProgress = null;
      _syncDetailMessage = 'Preparando sincronización...';
      _syncErrorMessage = null;
    });

    void updateSyncState(
      SyncStatus status, {
      double? progress,
      String? message,
    }) {
      if (!mounted || syncOperationId != _syncOperationId) {
        return;
      }

      setState(() {
        _syncStatus = status;
        _syncProgress = progress;
        _syncDetailMessage = message;
        if (status != SyncStatus.error) {
          _syncErrorMessage = null;
        }
      });
    }

    try {
      final Map<String, dynamic> result = await _repository!.performSync(
        forceFull: forceFull,
        onProgress: updateSyncState,
      );

      if (!mounted) {
        return;
      }

      if (result['error'] == true) {
        setState(() {
          _syncStatus = SyncStatus.error;
          _syncErrorMessage = result['message'] as String?;
          _syncProgress = null;
          _syncDetailMessage = null;
        });
      } else {
        setState(() {
          _syncStatus = SyncStatus.synced;
          _syncErrorMessage = null;
          _syncProgress = null;
          _syncDetailMessage = 'Sincronización completada';
          _homeRefreshToken += 1;
        });

        // Keep the completion state visible briefly so it can be read.
        Future<void>.delayed(const Duration(seconds: 1), () {
          if (mounted && syncOperationId == _syncOperationId) {
            setState(() {
              _syncStatus = SyncStatus.idle;
              _syncProgress = null;
              _syncDetailMessage = null;
            });
          }
        });
      }
    } catch (e, st) {
      if (!mounted) {
        return;
      }

      setState(() {
        _syncStatus = SyncStatus.error;
        _syncErrorMessage = '$e\n\nStackTrace: $st';
        _syncProgress = null;
        _syncDetailMessage = null;
      });
    }
  }

  Widget _buildLoadingScreen() {
    return const Scaffold(
      body: SafeArea(
        child: Column(
          children: [
            Expanded(
              child: Center(
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    CircularProgressIndicator(),
                    SizedBox(height: 16),
                    Text('Preparando el vault local...'),
                  ],
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildAppShell({required Widget home}) {
    return home;
  }

  Widget _buildMainShell(NoteRepository repository) {
    final AppPalette palette = _activePalette();
    final Widget activeScreen = _currentSection == _AppSection.home
        ? HomeScreen(
            key: const ValueKey<String>('home-screen'),
            repository: repository,
            onOpenSettings: _openSettings,
            onRequestSync: _performSync,
            onVaultInvalid: _resetLocalVaultData,
            syncStatus: _syncStatus,
            syncProgress: _syncProgress,
            syncDetailMessage: _syncDetailMessage,
            syncErrorMessage: _syncErrorMessage,
            refreshToken: _homeRefreshToken,
          )
        : SettingsScreen(
            key: const ValueKey<String>('settings-screen'),
            onDeleteAllData: _resetLocalVaultData,
            onBackToHome: _openHome,
            onForceSync: () => _performSync(forceFull: true),
            currentSeedColor: _themeSeedColor,
            onThemeColorSelected: _setThemeSeedColor,
            currentThemeMode: _themeMode,
            onThemeModeSelected: _setThemeMode,
          );

    return Shortcuts(
      shortcuts: <LogicalKeySet, Intent>{
        LogicalKeySet(LogicalKeyboardKey.f5): const PerformSyncIntent(),
      },
      child: Actions(
        actions: <Type, Action<Intent>>{
          PerformSyncIntent: CallbackAction<PerformSyncIntent>(
            onInvoke: (PerformSyncIntent intent) {
              _performSync();
              return null;
            },
          ),
        },
        child: Focus(
          autofocus: true,
          child: Scaffold(
            body: Container(
              decoration: BoxDecoration(gradient: palette.backdropGradient),
              child: SafeArea(
                child: Column(
                  children: [
                    Expanded(
                      child: AnimatedSwitcher(
                        duration: _screenTransitionDuration,
                        switchInCurve: Curves.easeOutCubic,
                        switchOutCurve: Curves.easeInCubic,
                        transitionBuilder:
                            (Widget child, Animation<double> animation) {
                              final Animation<Offset> offsetAnimation =
                                  Tween<Offset>(
                                    begin: const Offset(0.08, 0.0),
                                    end: Offset.zero,
                                  ).animate(animation);

                              return FadeTransition(
                                opacity: animation,
                                child: SlideTransition(
                                  position: offsetAnimation,
                                  child: child,
                                ),
                              );
                            },
                        child: activeScreen,
                      ),
                    ),
                    AnimatedSwitcher(
                      duration: const Duration(milliseconds: 180),
                      switchInCurve: Curves.easeOutCubic,
                      switchOutCurve: Curves.easeInCubic,
                      transitionBuilder:
                          (Widget child, Animation<double> animation) {
                            final Animation<Offset> slideAnimation =
                                Tween<Offset>(
                                  begin: const Offset(0.0, 0.35),
                                  end: Offset.zero,
                                ).animate(animation);

                            return FadeTransition(
                              opacity: animation,
                              child: SlideTransition(
                                position: slideAnimation,
                                child: child,
                              ),
                            );
                          },
                      child: _buildSyncBanner(context),
                    ),
                  ],
                ),
              ),
            ),
          ),
        ),
      ),
    );
  }

  @override
  void onWindowResize() {
    _scheduleWindowSizeSave();
  }

  @override
  void onWindowResized() {
    _scheduleWindowSizeSave();
  }

  @override
  void onWindowFocus() {
    _cancelBiometricLockTimer();
  }

  @override
  void onWindowBlur() {
    _scheduleBiometricLockTimer();
  }

  @override
  void onWindowClose() {
    if (_isHandlingWindowClose) {
      return;
    }

    _windowSizeSaveTimer?.cancel();
    _windowSizeSaveTimer = null;
    unawaited(_saveWindowSize());

    if (!_needsBiometricLock) {
      unawaited(_allowWindowClose());
      return;
    }

    _isHandlingWindowClose = true;
    _cancelBiometricLockTimer();

    unawaited(() async {
      try {
        final String? encryptionKey = await _vaultService.readEncryptionKey();
        if (encryptionKey == null) {
          return;
        }

        await _allowWindowClose();
      } finally {
        _isHandlingWindowClose = false;
      }
    }());
  }

  @override
  Widget build(BuildContext context) {
    Widget homeWidget;

    if (_isBootstrapping) {
      homeWidget = _buildLoadingScreen();
    } else {
      final NoteRepository? repository = _repository;

      if (repository != null) {
        homeWidget = _buildMainShell(repository);
      } else {
        switch (_phase) {
          case _AppPhase.loading:
            homeWidget = _buildLoadingScreen();
            break;
          case _AppPhase.access:
            homeWidget = _buildAppShell(
              home: VaultAccessScreen(
                isBusy: _isUnlocking,
                onCreateAccountPressed: (String email, String password) async {
                  await _beginRemoteVaultFlow(
                    username: email,
                    password: password,
                    isRegister: true,
                  );
                },
                onSignInPressed: (String email, String password) async {
                  await _beginRemoteVaultFlow(
                    username: email,
                    password: password,
                    isRegister: false,
                  );
                },
                onContinueWithoutAccount: _enterWithoutAccount,
              ),
            );
            break;
          case _AppPhase.biometricChoice:
            homeWidget = _buildAppShell(
              home: BiometricChoiceScreen(
                isBusy: _isUnlocking,
                onEnableBiometrics: () =>
                    _completeBiometricChoice(enableBiometrics: true),
                onSkipBiometrics: () =>
                    _completeBiometricChoice(enableBiometrics: false),
              ),
            );
            break;
          case _AppPhase.biometricGate:
            homeWidget = _buildAppShell(
              home: BiometricGateScreen(
                key: ValueKey<int>(_biometricGateSession),
                isBusy: _isUnlocking,
                onUnlockRequested: _unlockBiometricGate,
              ),
            );
            break;
          case _AppPhase.notes:
            homeWidget = _buildLoadingScreen();
            break;
        }
      }
    }

    return MaterialApp(
      navigatorKey: _navigatorKey,
      title: 'Mis Notas',
      debugShowCheckedModeBanner: false,
      scaffoldMessengerKey: _scaffoldMessengerKey,
      localizationsDelegates: const <LocalizationsDelegate<dynamic>>[
        GlobalMaterialLocalizations.delegate,
        GlobalWidgetsLocalizations.delegate,
        GlobalCupertinoLocalizations.delegate,
        FlutterQuillLocalizations.delegate,
      ],
      theme:
          _lightTheme ??
          AppTheme.theme(
            seedColor: _themeSeedColor,
            brightness: Brightness.light,
          ),
      darkTheme:
          _darkTheme ??
          AppTheme.theme(
            seedColor: _themeSeedColor,
            brightness: Brightness.dark,
          ),
      themeMode: _themeMode,
      home: homeWidget,
    );
  }
}