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

namespace Tango.Graphics2D
{
    public class Drawing2DFrame : Drawing2DHost
    {
        public override Point GetElementLocation(FrameworkElement element)
        {
            if (element.HorizontalAlignment == HorizontalAlignment.Left)
            {
                if (element.VerticalAlignment == VerticalAlignment.Top)
                {
                    return new Point(element.Margin.Left, element.Margin.Top);
                }
                else if (element.VerticalAlignment == VerticalAlignment.Bottom)
                {
                    return new Point(element.Margin.Left, ActualHeight - GetElementHeight(element) - element.Margin.Bottom);
                }
                else
                {
                    return new Point(element.Margin.Left, (ActualHeight / 2) - (GetElementHeight(element) / 2) + element.Margin.Top - element.Margin.Bottom);
                }
            }
            else if (element.HorizontalAlignment == HorizontalAlignment.Right)
            {
                if (element.VerticalAlignment == VerticalAlignment.Top)
                {
                    return new Point(ActualWidth - GetElementWidth(element) - element.Margin.Right, element.Margin.Top);
                }
                else if (element.VerticalAlignment == VerticalAlignment.Bottom)
                {
                    return new Point(ActualWidth - GetElementWidth(element) - element.Margin.Right, ActualHeight - GetElementHeight(element) - element.Margin.Bottom);
                }
                else
                {
                    return new Point(ActualWidth - GetElementWidth(element) - element.Margin.Right, (ActualHeight / 2) - (GetElementHeight(element) / 2) + element.Margin.Top - element.Margin.Bottom);
                }
            }
            else
            {
                if (element.VerticalAlignment == VerticalAlignment.Top)
                {
                    return new Point((ActualWidth / 2) - (GetElementWidth(element) / 2) + element.Margin.Left - element.Margin.Right, element.Margin.Top);
                }
                else if (element.VerticalAlignment == VerticalAlignment.Bottom)
                {
                    return new Point((ActualWidth / 2) - (GetElementWidth(element) / 2) + element.Margin.Left - element.Margin.Right, ActualHeight - GetElementHeight(element) - element.Margin.Bottom);
                }
                else
                {
                    return new Point((ActualWidth / 2) - (GetElementWidth(element) / 2) + element.Margin.Left, (ActualHeight / 2) - (GetElementHeight(element) / 2) + element.Margin.Top);
                }
            }
        }

        private double GetElementWidth(FrameworkElement element)
        {
            return double.IsNaN(element.Width) ? ActualWidth : element.Width;
        }

        private double GetElementHeight(FrameworkElement element)
        {
            return double.IsNaN(element.Height) ? ActualHeight : element.Height;
        }

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

            if (double.IsNaN(width))
            {
                width = ActualWidth;
            }
            if (double.IsNaN(height))
            {
                height = ActualHeight;
            }

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

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