import 'package:flutter/foundation.dart';

import '../services/admin_pin_service.dart';

class AdminPinViewModel extends ChangeNotifier {
  final AdminPinService adminPinService;

  AdminPinViewModel({required this.adminPinService});

  bool _isPinSet = false;
  bool _isUnlocked = false;
  bool _isLoading = false;
  bool _hasLoaded = false;
  String? _errorMessage;

  bool get isPinSet => _isPinSet;

  bool get isUnlocked => _isUnlocked;

  bool get isLoading => _isLoading;

  bool get hasLoaded => _hasLoaded;

  String? get errorMessage => _errorMessage;

  Future<void> ensureLoaded() async {
    if (_hasLoaded || _isLoading) return;

    await load();
  }

  Future<void> load() async {
    if (_isLoading) return;

    _isLoading = true;
    _errorMessage = null;
    notifyListeners();

    try {
      _isPinSet = await adminPinService.hasPin();
    } catch (e) {
      debugPrint('AdminPinViewModel: load error: $e');
      _errorMessage = 'Could not check PIN status.';
    } finally {
      _hasLoaded = true;
      _isLoading = false;
      notifyListeners();
    }
  }

  Future<bool> setPin(String pin) async {
    _errorMessage = null;

    try {
      await adminPinService.setPin(pin);
      _isPinSet = true;
      _isUnlocked = true;
      notifyListeners();
      return true;
    } catch (e) {
      debugPrint('AdminPinViewModel: setPin error: $e');
      _errorMessage = 'Could not save PIN.';
      notifyListeners();
      return false;
    }
  }

  Future<bool> verify(String pin) async {
    _errorMessage = null;

    try {
      final matches = await adminPinService.verifyPin(pin);

      if (matches) {
        _isUnlocked = true;
        notifyListeners();
        return true;
      }

      _errorMessage = 'Incorrect PIN.';
      notifyListeners();
      return false;
    } catch (e) {
      debugPrint('AdminPinViewModel: verify error: $e');
      _errorMessage = 'Could not verify PIN.';
      notifyListeners();
      return false;
    }
  }

  Future<bool> changePin({
    required String currentPin,
    required String newPin,
  }) async {
    final currentMatches = await adminPinService.verifyPin(currentPin);

    if (!currentMatches) {
      _errorMessage = 'Current PIN is incorrect.';
      notifyListeners();
      return false;
    }

    return setPin(newPin);
  }

  void lock() {
    if (!_isUnlocked) return;

    _isUnlocked = false;
    notifyListeners();
  }
}