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

namespace WGneu {
    public static class Utils {
        public static void SetInputChanged(Control input) {
            input.BorderBrush = Brushes.Orange;
        }

        public static void SetInputInvalid(Control input) {
            input.BorderBrush = Brushes.Red;
        }

        public static void ClearInputState(Control input) {
            input.ClearValue(Control.BorderBrushProperty);
        }

        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 IEnumerable<T> FindVisualChilds<T>(DependencyObject depObj, IEnumerable<DependencyObject> exempt) where T : DependencyObject {
            return FindVisualChilds<T>(depObj).Where(c => !exempt.Contains(c));
        }

        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);
        }

        public static void RunBackground(string title, Func<Task> a) {
            Task.Run(async () => {
                try {
                    await a();
                } catch (Exception e) {
                    MessageBox.Show(e.ToString(), title, MessageBoxButton.OK, MessageBoxImage.Error);
                }
            });
        }

        public sealed class TemporaryFile : IDisposable {
            private int Usages = 0;
            public string FilePath { get; private set; }

            public TemporaryFile() : this(null) {}

            public TemporaryFile(string? ext) : this(Path.Combine(Path.GetTempPath(), "Kelwin"), ext) {}

            public TemporaryFile(string dir, string? ext) {
                FilePath = Path.Combine(dir, Path.GetRandomFileName().Replace(".", "") + (ext != null ? $".{ext}" : ""));
                Usages++;
                Create();
            }

            ~TemporaryFile() {
                Delete();
            }

            public void Dispose() {
                if (--Usages == 0) {
                    Delete();
                    GC.SuppressFinalize(this);
                }
            }

            public TemporaryFile NewReference() {
                Usages++;
                return this;
            }

            private void Create() {
                using (File.Create(FilePath)) {};
            }

            private void Delete() {
                if (FilePath == null) return;
                File.Delete(FilePath);
                FilePath = null;
            }
        }
    }
}