inabox/inabox.wpf/WPFUtils.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Globalization;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
using InABox.Core;
using Microsoft.Xaml.Behaviors;
using Brush = System.Windows.Media.Brush;
using FontStyle = System.Windows.FontStyle;
using Image = System.Windows.Controls.Image;

namespace InABox.WPF
{
    public static class WPFUtils
    {
        public static T? FindLogicalParent<T>(this DependencyObject dependencyObject)
            where T : DependencyObject
        {
            DependencyObject? parent = dependencyObject; 
            do
            {
                parent = LogicalTreeHelper.GetParent(parent);
            } while(parent != null && parent is not T);
            return parent as T;
        }

        public static int GetRow(this Grid grid, DependencyObject dependencyObject)
        {
            while (true)
            {
                var parent = LogicalTreeHelper.GetParent(dependencyObject);
                if (parent == null)
                    return -1;
                if (parent == grid)
                    return Grid.GetRow(dependencyObject as UIElement);
                dependencyObject = parent;
            }
        }

        public static int GetRowSpan(this Grid grid, DependencyObject dependencyObject)
        {
            while (true)
            {
                var parent = LogicalTreeHelper.GetParent(dependencyObject);
                if (parent == null)
                    return -1;
                if (parent == grid)
                    return Grid.GetRowSpan(dependencyObject as UIElement);
                dependencyObject = parent;
            }
        }
       
        public static int GetColumn(this Grid grid, DependencyObject dependencyObject)
        {
            while (true)
            {
                var parent = LogicalTreeHelper.GetParent(dependencyObject);
                if (parent == null)
                    return -1;
                if (parent == grid)
                    return Grid.GetColumn(dependencyObject as UIElement);
                dependencyObject = parent;
            }
        }

        public static int GetColumnSpan(this Grid grid, DependencyObject dependencyObject)
        {
            while (true)
            {
                var parent = LogicalTreeHelper.GetParent(dependencyObject);
                if (parent == null)
                    return -1;
                if (parent == grid)
                    return Grid.GetColumnSpan(dependencyObject as UIElement);
                dependencyObject = parent;
            }
        }
       
        public static void SetGridPosition(this FrameworkElement element, int row, int column, int rowspan = 1, int colspan = 1)
        {
            element.SetValue(Grid.ColumnProperty, column);
            element.SetValue(Grid.ColumnSpanProperty, Math.Max(1, colspan));
            element.SetValue(Grid.RowProperty, row);
            element.SetValue(Grid.RowSpanProperty, Math.Max(1, rowspan));
        }

        public static IEnumerable<T> FindVisualChildren<T>(this DependencyObject depObj)
        {
            if (depObj != null)
                //ContentControl cc = depObj as ContentControl;
                //if (cc != null)
                //{
                //    if (cc.Content == null)
                //        yield return null;
                //    if (cc.Content is T)
                //        yield return cc.Content as T;
                //    foreach (var child in FindVisualChildren<T>(cc.Content as DependencyObject))
                //        yield return child;
                //}
                //else
                for (var i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
                {
                    var child = VisualTreeHelper.GetChild(depObj, i);
                    if (child is null)
                        continue;

                    if (child is T t)
                        yield return t;

                    foreach (var childOfChild in FindVisualChildren<T>(child))
                        yield return childOfChild;
                }
        }

        #region Menu Utils

        private static void ItemsControlInsert(ItemsControl menu, FrameworkElement item, int index)
        {
            if (index != -1)
            {
                menu.Items.Insert(index, item);
            }
            else
            {
                menu.Items.Add(item);
            }
        }

        private static MenuItem DoAddMenuItem(ItemsControl menu, string caption, Bitmap? image, bool enabled, int index = -1)
        {
            var item = new MenuItem { Header = caption, IsEnabled = enabled };
            if (image != null)
                item.Icon = new Image() { Source = enabled ? image.AsBitmapImage(24, 24) : image.AsGrayScale().AsBitmapImage(24, 24) };

            ItemsControlInsert(menu, item, index);
            return item;
        }

        private static MenuItem DoAddMenuItem(ItemsControl menu, string caption, Bitmap? image, Action? click, bool enabled, int index = -1)
        {
            var item = DoAddMenuItem(menu, caption, image, enabled, index);

            if (click != null)
            {
                item.Click += (o, e) =>
                {
                    click();
                };
            }

            return item;
        }
        private static MenuItem DoAddMenuItem<T>(ItemsControl menu, string caption, Bitmap? image, T tag, Action<T> click, bool enabled, int index = -1)
        {
            var item = DoAddMenuItem(menu, caption, image, enabled, index);

            item.Tag = tag;
            item.Click += (o, e) =>
            {
                click((T)(o as MenuItem)!.Tag);
            };

            return item;
        }

        public delegate void CheckToggleAction<T>(T tag, bool isChecked);

        private static MenuItem DoAddCheckItem<T>(ItemsControl menu, string caption, T tag, CheckToggleAction<T> click, bool isChecked, bool enabled, int index = -1)
        {
            var item = new MenuItem { Header = caption, IsEnabled = enabled, IsCheckable = true, IsChecked = isChecked };

            item.Tag = tag;
            item.Click += (o, e) =>
            {
                click((T)(o as MenuItem)!.Tag, item.IsChecked);
            };

            ItemsControlInsert(menu, item, index);
            return item;
        }

        private static Separator DoAddSeparator(ItemsControl menu, int index)
        {
            var separator = new Separator();

            ItemsControlInsert(menu, separator, index);

            return separator;
        }
        private static Separator DoAddSeparatorIfNeeded(ItemsControl menu, int index)
        {
            if (menu.Items.Count == 0) return null;

            var lastIndex = index != -1 ? index - 1 : menu.Items.Count - 1;
            if (lastIndex < 0 || lastIndex >= menu.Items.Count) return null;

            var last = menu.Items[lastIndex];
            if (last is Separator) return null;

            var separator = new Separator();

            ItemsControlInsert(menu, separator, index);

            return separator;
        }

        private static void DoRemoveUnnecessarySeparators(ItemsControl menu)
        {
            while(menu.Items.Count > 0 && menu.Items[0] is Separator)
            {
                menu.Items.RemoveAt(0);
            }
            while(menu.Items.Count > 0 && menu.Items[^1] is Separator)
            {
                menu.Items.RemoveAt(menu.Items.Count - 1);
            }
        }

        public static Separator AddSeparator(this ContextMenu menu, int index = -1) => DoAddSeparator(menu, index);
        public static Separator AddSeparator(this MenuItem menu, int index = -1) => DoAddSeparator(menu, index);
        public static Separator? AddSeparatorIfNeeded(this ContextMenu menu, int index = -1) => DoAddSeparatorIfNeeded(menu, index);
        public static Separator? AddSeparatorIfNeeded(this MenuItem menu, int index = -1) => DoAddSeparatorIfNeeded(menu, index);
        public static void RemoveUnnecessarySeparators(this ContextMenu menu) => DoRemoveUnnecessarySeparators(menu);
        public static void RemoveUnnecessarySeparators(this MenuItem menu) => DoRemoveUnnecessarySeparators(menu);

        public static MenuItem AddItem(this ContextMenu menu, string caption, Bitmap? image, Action? click, bool enabled = true, int index = -1)
            => DoAddMenuItem(menu, caption, image, click, enabled, index);
        public static MenuItem AddItem(this MenuItem menu, string caption, Bitmap? image, Action? click, bool enabled = true, int index = -1)
            => DoAddMenuItem(menu, caption, image, click, enabled, index);
        public static MenuItem AddItem<T>(this ContextMenu menu, string caption, Bitmap? image, T tag, Action<T> click, bool enabled = true, int index = -1)
            => DoAddMenuItem(menu, caption, image, tag, click, enabled, index);
        public static MenuItem AddItem<T>(this MenuItem menu, string caption, Bitmap? image, T tag, Action<T> click, bool enabled = true, int index = -1)
            => DoAddMenuItem(menu, caption, image, tag, click, enabled, index);
        public static MenuItem AddCheckItem<T>(this ContextMenu menu, string caption, T tag, CheckToggleAction<T> click, bool isChecked = false, bool enabled = true, int index = -1)
            => DoAddCheckItem<T>(menu, caption, tag, click, isChecked, enabled, index);

        #endregion
    }

    public class TextBoxPlaceholderBehaviour : Behavior<TextBox>
    {
        
        public static readonly DependencyProperty TextProperty =
            DependencyProperty.Register(
                nameof(Text),
                typeof(String),
                typeof(TextBoxPlaceholderBehaviour),
                new PropertyMetadata(""));

        public String Text
        {
            get => (String)GetValue(TextProperty);
            set
            {
                SetValue(TextProperty, value);
                UpdateAssociatedObject();
            }
        }
        
        public static readonly DependencyProperty TextColorProperty =
            DependencyProperty.Register(
                nameof(TextColor),
                typeof(System.Windows.Media.Color),
                typeof(TextBoxPlaceholderBehaviour),
                new PropertyMetadata(Colors.Gray));

        public System.Windows.Media.Color TextColor
        {
            get => (System.Windows.Media.Color)GetValue(TextColorProperty);
            set
            {
                SetValue(TextColorProperty, value);
                UpdateAssociatedObject();
            }
        }
        
        private readonly PropertyDescriptor _propertyDescriptor = 
            DependencyPropertyDescriptor.FromProperty(TextBox.BackgroundProperty, typeof(TextBox));
        
        private Brush? _originalBackground;
        private Brush? _placeholderBackground;
        
        protected override void OnAttached()
        {
            base.OnAttached();

            // Store the Background that has been set on the Text Box (usu through XAML)
            _originalBackground = AssociatedObject.Background;
            
            // Start Monitoring changes to the Associated object Background property
            _propertyDescriptor.AddValueChanged(AssociatedObject, OnBackgroundChanged);
            
            AssociatedObject.TextChanged += OnTextChanged;
            AssociatedObject.SizeChanged += OnSizeChanged;
            
            UpdateAssociatedObject();
        }
        
        protected override void OnDetaching()
        {
            AssociatedObject.SizeChanged -= OnSizeChanged;
            AssociatedObject.TextChanged -= OnTextChanged;

            _propertyDescriptor?.RemoveValueChanged(AssociatedObject,OnBackgroundChanged);

            AssociatedObject.Background = _originalBackground;
            
            base.OnDetaching();
        }
        
        
        private void OnBackgroundChanged(object? sender, EventArgs e)
        {
            // Update the Saved Background (usu a color, but might not be?)
            _originalBackground = AssociatedObject.Background;
            _placeholderBackground = null;
            UpdateAssociatedObject();
        }

        private void OnTextChanged(object sender, TextChangedEventArgs e)
        {
            UpdateAssociatedObject();
        }

        private void SetBackground(Brush? brush)
        {
            _propertyDescriptor.RemoveValueChanged(AssociatedObject, OnBackgroundChanged);
            AssociatedObject.Background = brush;
            _propertyDescriptor.AddValueChanged(AssociatedObject, OnBackgroundChanged);
        }
        
        private void OnSizeChanged(object sender, SizeChangedEventArgs e)
        {
            _placeholderBackground = null;
            UpdateAssociatedObject();
        }
        
        private Brush CreatePlaceholder()
        {
            return new VisualBrush()
            {
                Visual = new Label()
                {
                    Content = Text,
                    Margin = new Thickness(0),
                    Padding = new Thickness(4, 0, 2, 0),
                    HorizontalAlignment = HorizontalAlignment.Stretch,
                    VerticalAlignment = VerticalAlignment.Stretch,
                    HorizontalContentAlignment = AssociatedObject.HorizontalContentAlignment,
                    VerticalContentAlignment = AssociatedObject.VerticalContentAlignment,
                    FontFamily = AssociatedObject.FontFamily,
                    FontStretch = AssociatedObject.FontStretch,
                    FontSize = AssociatedObject.FontSize,
                    FontWeight = AssociatedObject.FontWeight,
                    FontStyle = FontStyles.Italic,
                    Background = _originalBackground?.Clone(),
                    Foreground = new SolidColorBrush(TextColor),
                    Width = AssociatedObject.ActualWidth,
                    Height = AssociatedObject.ActualHeight
                },
                Stretch = Stretch.None,
                TileMode = TileMode.None,
                AlignmentX = AlignmentX.Left,
                AlignmentY = AlignmentY.Center
            };
        }
        
        private void UpdateAssociatedObject()
        {
            if (String.IsNullOrWhiteSpace(AssociatedObject.Text) && _placeholderBackground == null)
            {
                _placeholderBackground = CreatePlaceholder();
                SetBackground(_placeholderBackground);
            }
            else if (!String.IsNullOrWhiteSpace(AssociatedObject.Text) && _placeholderBackground != null)
            { 
                _placeholderBackground = null;
                SetBackground(_originalBackground);
            }
        }
    }

    // public class TextBoxPlaceholderBehaviour : Behavior<TextBox>
    // {
    //     
    //     public static readonly DependencyProperty TextProperty =
    //         DependencyProperty.Register(
    //             nameof(Text), 
    //             typeof(String), 
    //             typeof(TextBoxPlaceholderBehaviour), 
    //             new PropertyMetadata(""));
    //     
    //
    //     public String Text
    //     {
    //         get => (String)GetValue(TextProperty);
    //         set => SetValue(TextProperty, value);
    //     }
    //     
    //     protected override void OnAttached()
    //     {
    //         base.OnAttached();
    //         AssociatedObject.GotFocus += AssociatedObjectOnGotFocus;
    //         AssociatedObject.LostFocus += AssociatedObjectOnLostFocus;
    //     }
    //
    //     protected override void OnDetaching()
    //     {
    //         AssociatedObject.GotFocus -= AssociatedObjectOnGotFocus;
    //         AssociatedObject.LostFocus -= AssociatedObjectOnLostFocus;
    //         base.OnDetaching();
    //     }
    //
    //     private void AssociatedObjectOnGotFocus(object sender, RoutedEventArgs e)
    //     {
    //         if (String.Equals(AssociatedObject.Text, Text))
    //         {
    //             AssociatedObject.Text = "";
    //             AssociatedObject.Foreground = new SolidColorBrush(Colors.Black);
    //         }
    //     }
    //
    //     private void AssociatedObjectOnLostFocus(object sender, RoutedEventArgs e)
    //     {
    //         if (String.IsNullOrWhiteSpace(AssociatedObject.Text))
    //         {
    //             AssociatedObject.Text = Text;
    //             AssociatedObject.Foreground = new SolidColorBrush(Colors.Gray);
    //         }
    //     }
    // }
    
    public class TextBoxEnterAsTabBehavior :
        Behavior<TextBox>
    {
        protected override void OnAttached()
        {
            base.OnAttached();
            AssociatedObject.PreviewKeyDown += AssociatedObjectOnPreviewKeyDown;
        }

        protected override void OnDetaching()
        {
            AssociatedObject.PreviewKeyDown -= AssociatedObjectOnPreviewKeyDown;
            base.OnDetaching();
        }

        private void AssociatedObjectOnPreviewKeyDown(object sender, KeyEventArgs args)
        {
            if (args.Key != Key.Enter) { return; }

            args.Handled = true;
            AssociatedObject.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
        }
    }
}