using System.Windows;
using System.Windows.Controls;
using System.ComponentModel;
using System.Windows.Threading;
using UtopiaCanteenSystem.ViewModels;

namespace UtopiaCanteenSystem.Views;

/// <summary>
/// Minimal code-behind for PasswordBox + initial focus.
/// </summary>
public partial class AdminLoginView : UserControl
{
    private AdminLoginViewModel? _vm;

    public AdminLoginView()
    {
        InitializeComponent();
        Loaded += OnLoaded;
        DataContextChanged += OnDataContextChanged;
    }

    private void OnLoaded(object sender, RoutedEventArgs e)
    {
        Dispatcher.BeginInvoke(() =>
        {
            // Ensure stale PasswordBox contents never carry across sessions (PasswordBox isn't bindable).
            PasswordBox.Password = string.Empty;
            if (DataContext is AdminLoginViewModel vm)
                vm.Password = string.Empty;

            UsernameTextBox.Focus();
            UsernameTextBox.SelectAll();
        }, DispatcherPriority.Input);
    }

    private void OnDataContextChanged(object sender, DependencyPropertyChangedEventArgs e)
    {
        if (_vm != null)
            _vm.PropertyChanged -= VmOnPropertyChanged;

        _vm = DataContext as AdminLoginViewModel;
        if (_vm != null)
            _vm.PropertyChanged += VmOnPropertyChanged;

        // When we navigate back here after logout, the view might be reused; always clear password UI.
        PasswordBox.Password = string.Empty;
        if (DataContext is AdminLoginViewModel vm)
            vm.Password = string.Empty;
    }

    private void VmOnPropertyChanged(object? sender, PropertyChangedEventArgs e)
    {
        if (!string.Equals(e.PropertyName, nameof(AdminLoginViewModel.Password), StringComparison.Ordinal))
            return;

        // Keep PasswordBox UI in sync when VM clears password after clicking Login.
        if (_vm != null && string.IsNullOrEmpty(_vm.Password) && !string.IsNullOrEmpty(PasswordBox.Password))
            PasswordBox.Password = string.Empty;
    }

    private void PasswordBox_OnPasswordChanged(object sender, RoutedEventArgs e)
    {
        if (DataContext is AdminLoginViewModel vm)
            vm.Password = PasswordBox.Password;
    }
}