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

namespace WGneu {
    class Utils {
        public static IEnumerable<T> FindVisualChilds<T>(DependencyObject depObj) where T : DependencyObject {
            if (depObj == null)
                yield return (T)Enumerable.Empty<T>();
            for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++) {
                DependencyObject ithChild = VisualTreeHelper.GetChild(depObj, i);
                if (ithChild == null)
                    continue;
                if (ithChild is T t)
                    yield return t;
                foreach (T childOfChild in FindVisualChilds<T>(ithChild))
                    yield return childOfChild;
            }
        }

        public static int Modulo(string a, int b) {
            if (!a.All(char.IsDigit))
                throw new ArgumentException("First argument has to be a decimal string");
            return a.Select(ch => ch - '0').Aggregate((sum, n) => (sum * 10 + n) % b);
        }
    }
}