using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;

namespace TestDataGrid;

/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow
{
    public MainWindowViewModel ViewModel
    {
        get => DataContext as MainWindowViewModel;
        set => DataContext = value;
    }

    public MainWindow()
    {
        InitializeComponent();
    }

    private void Digit_OnPreviewTextInput(object sender, TextCompositionEventArgs e)
    {
        e.Handled = "0123456789".IndexOf(e.Text, StringComparison.Ordinal) < 0;
    }

    public void RefreshFromTopAndRestorePosition(Action updateData)
    {
        var scrollViewer =
            FindVisualChild<ScrollViewer>(BusinesDataGrid);

        if (scrollViewer == null)
        {
            updateData();
            return;
        }

        var verticalOffset = scrollViewer.VerticalOffset;
        var horizontalOffset = scrollViewer.HorizontalOffset;

        scrollViewer.ScrollToTop();
        BusinesDataGrid.UpdateLayout();

        updateData();

        BusinesDataGrid.UpdateLayout();

        scrollViewer =
            FindVisualChild<ScrollViewer>(BusinesDataGrid);

        if (scrollViewer == null)
            return;

        var restoredVerticalOffset = Math.Min(
            verticalOffset,
            scrollViewer.ScrollableHeight);

        var restoredHorizontalOffset = Math.Min(
            horizontalOffset,
            scrollViewer.ScrollableWidth);

        scrollViewer.ScrollToVerticalOffset(
            restoredVerticalOffset);

        scrollViewer.ScrollToHorizontalOffset(
            restoredHorizontalOffset);

        BusinesDataGrid.UpdateLayout();
    }

    private static T? FindVisualChild<T>(
        DependencyObject parent)
        where T : DependencyObject
    {
        for (var i = 0;
             i < VisualTreeHelper.GetChildrenCount(parent);
             i++)
        {
            var child =
                VisualTreeHelper.GetChild(parent, i);

            if (child is T result)
                return result;

            var descendant =
                FindVisualChild<T>(child);

            if (descendant != null)
                return descendant;
        }

        return null;
    }
}