using System.Globalization;
using System.Windows;
using System.Windows.Data;
using System.Windows.Markup;

namespace Qrakhen.TilingFrames.Converters
{
   public class AlphaRatioConverter : MarkupExtension, IValueConverter
   {
      public override object ProvideValue(IServiceProvider serviceProvider) => this;

      public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
      {
         if (value is double ratio) {
            if (ratio <= double.Epsilon)
               return new GridLength(0, GridUnitType.Star);
            if (ratio <= .5)
               return new GridLength(1, GridUnitType.Star);
            else if (ratio >= 1)
               return new GridLength(1, GridUnitType.Star);
            return new GridLength((1 - ratio) / ratio, GridUnitType.Star);
         }

         throw new ArgumentException($"Expected value to be ratio (double), god {value} instead.");
      }

      public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) 
         => throw new NotImplementedException();
   }
}