using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;

namespace Tango.Graphics2D
{
    public class Drawing2DStackPanel : Drawing2DHost
    {
        private double _currentPosition = 0;
        private double _maxPosition = 0;

        public Orientation Orientation
        {
            get { return (Orientation)GetValue(OrientationProperty); }
            set { SetValue(OrientationProperty, value); }
        }
        public static readonly DependencyProperty OrientationProperty =
            DependencyProperty.Register("Orientation", typeof(Orientation), typeof(Drawing2DStackPanel), new PropertyMetadata(Orientation.Vertical));

        public override Point GetElementLocation(FrameworkElement element)
        {
            if (Orientation == Orientation.Vertical)
            {
                _currentPosition += element.Margin.Top;

                Point location = new Point(0, 0);

                if (element.HorizontalAlignment == HorizontalAlignment.Left)
                {
                    location = new Point(element.Margin.Left, _currentPosition);
                }
                else if (element.HorizontalAlignment == HorizontalAlignment.Right)
                {
                    location = new Point(ActualWidth - element.Width - element.Margin.Right, _currentPosition);
                }
                else
                {
                    location = new Point((ActualWidth / 2) - (element.Width / 2) + element.Margin.Left - element.Margin.Right, _currentPosition);
                }

                _currentPosition += (element.Height + element.Margin.Bottom);

                _maxPosition = Math.Max(_maxPosition, element.Width);

                return location;
            }
            else
            {
                _currentPosition += element.Margin.Left;

                Point location = new Point(0, 0);

                if (element.VerticalAlignment == VerticalAlignment.Top)
                {
                    location = new Point(_currentPosition, element.Margin.Top);
                }
                else if (element.VerticalAlignment == VerticalAlignment.Bottom)
                {
                    location = new Point(_currentPosition, ActualHeight - element.Height - element.Margin.Bottom);
                }
                else
                {
                    location = new Point(_currentPosition, (ActualHeight / 2) - (element.Height / 2) + element.Margin.Top - element.Margin.Bottom);
                }

                _currentPosition += (element.Width + element.Margin.Right);

                _maxPosition = Math.Max(_maxPosition, element.Height);

                return location;
            }
        }

        protected override Size OnMeasure()
        {
            if (Orientation == Orientation.Vertical)
            {
                return new Size(HorizontalAlignment != HorizontalAlignment.Stretch ? _maxPosition : double.NaN, _currentPosition);
            }
            else
            {
                return new Size(_currentPosition, _maxPosition);
            }
        }

        public override Size GetElementSize(FrameworkElement element)
        {
            double width = element.Width;
            double height = element.Height;

            if (double.IsNaN(width) && Orientation == Orientation.Vertical)
            {
                width = ActualWidth;
            }
            if (double.IsNaN(height) && Orientation == Orientation.Horizontal)
            {
                height = ActualHeight;
            }

            width -= (element.Margin.Left + element.Margin.Right);
            height -= (element.Margin.Top + element.Margin.Bottom);

            return new Size(width, height);
        }
    }
}