using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows;
using System.Windows.Controls;

namespace Notifications.Wpf.Controls
{
    public class ReversibleStackPanel : StackPanel
    {


        public bool ReverseOrder
        {
            get { return (bool)GetValue(ReverseOrderProperty); }
            set { SetValue(ReverseOrderProperty, value); }
        }
        
        public static readonly DependencyProperty ReverseOrderProperty =
            DependencyProperty.Register("ReverseOrder", typeof(bool), typeof(ReversibleStackPanel), new PropertyMetadata(false));


        protected override Size ArrangeOverride(Size arrangeSize)
        {
            double x = 0;
            double y = 0;

            IEnumerable<UIElement> children = ReverseOrder ? InternalChildren.Cast<UIElement>().Reverse() : InternalChildren.Cast<UIElement>();
            foreach (UIElement child in children)
            {
                Size size;

                if (Orientation == Orientation.Horizontal)
                {
                    size = new Size(child.DesiredSize.Width, Math.Max(arrangeSize.Height, child.DesiredSize.Height));
                    child.Arrange(new Rect(new Point(x, y), size));
                    x += size.Width;
                }
                else
                {
                    size = new Size(Math.Max(arrangeSize.Width, child.DesiredSize.Width), child.DesiredSize.Height);
                    child.Arrange(new Rect(new Point(x, y), size));
                    y += size.Height;
                }
            }

            return Orientation == Orientation.Horizontal ? new Size(x, arrangeSize.Height) : new Size(arrangeSize.Width, y);
        }
    }
}