using System.Windows;
using System.Windows.Controls;
using Microsoft.Xaml.Behaviors;
using Syncfusion.Windows.Controls.Gantt;
using Syncfusion.Windows.Controls.Gantt.Chart;
using Syncfusion.Windows.Controls.Grid;
using DependencyObjectExtensions = Syncfusion.Windows.Controls.Gantt.DependencyObjectExtensions;

namespace PRSDesktop
{
    public class GanttSetupBehaviour : Behavior<GanttControl>
    {
        /// <summary>
        ///     Called when [attached].
        /// </summary>
        protected override void OnAttached()
        {
            AssociatedObject.Loaded += AssociatedObject_Loaded;
        }

        /// <summary>
        ///     Handles the Loaded event of the AssociatedObject control.
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">The <see cref="System.Windows.RoutedEventArgs" /> instance containing the event data.</param>
        private void AssociatedObject_Loaded(object sender, RoutedEventArgs e)
        {
            if (AssociatedObject.GanttGrid != null) AssociatedObject.GanttGrid.UpdateMode = UpdateMode.PropertyChanged;

            var chart = DependencyObjectExtensions.FindName<GanttChart>(AssociatedObject, "PART_GanttChart");
            if (chart != null)
            {
                var chartScrollViewer =
                    DependencyObjectExtensions.FindName<ScrollViewer>(chart, "PART_GanttChartScrollViewer");
                if (chartScrollViewer != null)
                {
                    // To make the GanttChart's Vertical Scroll bar visible.
                    chartScrollViewer.VerticalScrollBarVisibility = ScrollBarVisibility.Visible;
                    chartScrollViewer.ScrollChanged += ChartScrollViewer_ScrollChanged;
                }
            }
        }

        private void ChartScrollViewer_ScrollChanged(object sender, ScrollChangedEventArgs e)
        {
            // To sync the GanttGrid's vertical scroll with GanttChart's Vertical scroll offset.
            AssociatedObject.GanttGrid.InternalGrid.SetVerticalOffset(e.VerticalOffset);
        }

        /// <summary>
        ///     Called when [detaching].
        /// </summary>
        protected override void OnDetaching()
        {
            AssociatedObject.Loaded -= AssociatedObject_Loaded;
        }
    }
}