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

namespace UtopiaCanteenSystem.Views;

/// <summary>
/// Scanner view: minimal code-behind for focus management and Enter-key submission.
/// </summary>
public partial class ScannerView : UserControl
{
    private bool _isUnloaded;

    public ScannerView()
    {
        InitializeComponent();
        Loaded += OnLoaded;
        Unloaded += OnUnloaded;
    }

    private void OnLoaded(object sender, RoutedEventArgs e)
    {
        _isUnloaded = false;
        FocusRfidInput(selectAll: true, DispatcherPriority.Input);
    }

    private void OnUnloaded(object sender, RoutedEventArgs e)
    {
        _isUnloaded = true;
    }

    private void FocusRfidInput(bool selectAll, DispatcherPriority priority)
    {
        if (_isUnloaded)
            return;

        Dispatcher.BeginInvoke(() =>
        {
            if (_isUnloaded || !IsVisible || !IsEnabled)
                return;

            RfidInputTextBox.Focus();
            Keyboard.Focus(RfidInputTextBox);

            if (selectAll)
                RfidInputTextBox.SelectAll();
        }, priority);
    }

    private void RfidInputTextBox_OnLostKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
    {
        // Keep the view "scan ready" by restoring focus to the RFID TextBox.
        // Use a low priority so clicks (e.g., Logout) complete first.
        FocusRfidInput(selectAll: false, DispatcherPriority.ApplicationIdle);
    }

    private void RfidInputTextBox_OnKeyDown(object sender, KeyEventArgs e)
    {
        if (e.Key != Key.Enter)
            return;

        if (DataContext is ScannerViewModel vm && vm.ScanCommand.CanExecute(null))
        {
            vm.ScanCommand.Execute(null);
            e.Handled = true;
        }
    }
}