Terminal.Gui/UICatalog/Scenarios/AdornmentEditor.cs

using System;
using Terminal.Gui;

namespace UICatalog.Scenarios;

/// <summary>
///     Provides a composable UI for editing the settings of an Adornment.
/// </summary>
public class AdornmentEditor : View
{
    private readonly ColorPicker16 _backgroundColorPicker = new ()
    {
        Title = "_BG",
        BoxWidth = 1,
        BoxHeight = 1,
        BorderStyle = LineStyle.Single,
        SuperViewRendersLineCanvas = true,
        Enabled = false
    };

    private readonly ColorPicker16 _foregroundColorPicker = new ()
    {
        Title = "_FG",
        BoxWidth = 1,
        BoxHeight = 1,
        BorderStyle = LineStyle.Single,
        SuperViewRendersLineCanvas = true,
        Enabled = false
    };

    private Adornment _adornment;
    public Adornment AdornmentToEdit
    {
        get => _adornment;
        set
        {
            if (value == _adornment)
            {
                return;
            }

            _adornment = value;

            foreach (var subview in Subviews)
            {
                subview.Enabled = _adornment is { };
            }

            if (_adornment is null)
            {
                return;
            }

            if (IsInitialized)
            {
                _topEdit.Value = _adornment.Thickness.Top;
                _leftEdit.Value = _adornment.Thickness.Left;
                _bottomEdit.Value = _adornment.Thickness.Bottom;
                _rightEdit.Value = _adornment.Thickness.Right;

                _adornment.Initialized += (sender, args) =>
                                          {
                                              var cs = _adornment.ColorScheme;
                                              _foregroundColorPicker.SelectedColor = cs.Normal.Foreground.GetClosestNamedColor ();
                                              _backgroundColorPicker.SelectedColor = cs.Normal.Background.GetClosestNamedColor ();

                                          };
            }

            OnAdornmentChanged ();
        }
    }

    public event EventHandler<EventArgs> AdornmentChanged;

    public void OnAdornmentChanged ()
    {
        AdornmentChanged?.Invoke (this, EventArgs.Empty);
    }

    private NumericUpDown<int> _topEdit;
    private NumericUpDown<int> _leftEdit;
    private NumericUpDown<int> _bottomEdit;
    private NumericUpDown<int> _rightEdit;

    public AdornmentEditor ()
    {
        Width = Dim.Auto (DimAutoStyle.Content);
        Height = Dim.Auto (DimAutoStyle.Content);

        BorderStyle = LineStyle.Dashed;
        Initialized += AdornmentEditor_Initialized;

        CanFocus = true;
        TabStop = TabBehavior.TabStop;
    }

    private void AdornmentEditor_Initialized (object sender, EventArgs e)
    {
        ExpanderButton expandButton;
        Border.Add (expandButton = new ExpanderButton ());

        _topEdit = new ()
        {
            X = Pos.Center (), Y = 0,
            Format = "{0, 2}",
            Enabled = false
        };

        _topEdit.ValueChanging += Top_ValueChanging;
        Add (_topEdit);

        _leftEdit = new ()
        {
            X = Pos.Left (_topEdit) - Pos.Func (() => _topEdit.Text.Length) - 2, Y = Pos.Bottom (_topEdit),
            Format = _topEdit.Format,
            Enabled = false
        };

        _leftEdit.ValueChanging += Left_ValueChanging;
        Add (_leftEdit);

        _rightEdit = new ()
        {
            X = Pos.Right (_leftEdit) + 5, Y = Pos.Bottom (_topEdit),
            Format = _topEdit.Format,
            Enabled = false
        };

        _rightEdit.ValueChanging += Right_ValueChanging;
        Add (_rightEdit);

        _bottomEdit = new ()
        {
            X = Pos.Center (), Y = Pos.Bottom (_leftEdit),
            Format = _topEdit.Format,
            Enabled = false
        };

        _bottomEdit.ValueChanging += Bottom_ValueChanging;
        Add (_bottomEdit);

        var copyTop = new Button
        {
            X = Pos.Center (), Y = Pos.Bottom (_bottomEdit), Text = "Cop_y Top",
            Enabled = false
        };

        copyTop.Accept += (s, e) =>
                          {
                              AdornmentToEdit.Thickness = new (_topEdit.Value);
                              _leftEdit.Value = _rightEdit.Value = _bottomEdit.Value = _topEdit.Value;
                          };
        Add (copyTop);

        // Foreground ColorPicker.
        _foregroundColorPicker.X = 0;
        _foregroundColorPicker.Y = Pos.Bottom (copyTop);

        _foregroundColorPicker.ColorChanged += ColorPickerColorChanged ();
        Add (_foregroundColorPicker);

        // Background ColorPicker.
        _backgroundColorPicker.X = Pos.Right (_foregroundColorPicker) - 1;
        _backgroundColorPicker.Y = Pos.Top (_foregroundColorPicker);

        _backgroundColorPicker.ColorChanged += ColorPickerColorChanged ();
        Add (_backgroundColorPicker);

        _topEdit.Value = AdornmentToEdit?.Thickness.Top ?? 0;
        _leftEdit.Value = AdornmentToEdit?.Thickness.Left ?? 0;
        _rightEdit.Value = AdornmentToEdit?.Thickness.Right ?? 0;
        _bottomEdit.Value = AdornmentToEdit?.Thickness.Bottom ?? 0;

        foreach (var subview in Subviews)
        {
            subview.Enabled = AdornmentToEdit is { };
        }
    }

    private EventHandler<ColorEventArgs> ColorPickerColorChanged ()
    {
        return (o, a) =>
               {
                   if (AdornmentToEdit is null)
                   {
                       return;
                   }
                   AdornmentToEdit.ColorScheme = new (AdornmentToEdit.ColorScheme)
                   {
                       Normal = new (_foregroundColorPicker.SelectedColor, _backgroundColorPicker.SelectedColor)
                   };
               };
    }

    private void Top_ValueChanging (object sender, CancelEventArgs<int> e)
    {
        if (e.NewValue < 0 || AdornmentToEdit is null)
        {
            e.Cancel = true;

            return;
        }

        AdornmentToEdit.Thickness = new (AdornmentToEdit.Thickness.Left, e.NewValue, AdornmentToEdit.Thickness.Right, AdornmentToEdit.Thickness.Bottom);
    }

    private void Left_ValueChanging (object sender, CancelEventArgs<int> e)
    {
        if (e.NewValue < 0 || AdornmentToEdit is null)
        {
            e.Cancel = true;

            return;
        }

        AdornmentToEdit.Thickness = new (e.NewValue, AdornmentToEdit.Thickness.Top, AdornmentToEdit.Thickness.Right, AdornmentToEdit.Thickness.Bottom);
    }

    private void Right_ValueChanging (object sender, CancelEventArgs<int> e)
    {
        if (e.NewValue < 0 || AdornmentToEdit is null)
        {
            e.Cancel = true;

            return;
        }

        AdornmentToEdit.Thickness = new (AdornmentToEdit.Thickness.Left, AdornmentToEdit.Thickness.Top, e.NewValue, AdornmentToEdit.Thickness.Bottom);
    }

    private void Bottom_ValueChanging (object sender, CancelEventArgs<int> e)
    {
        if (e.NewValue < 0 || AdornmentToEdit is null)
        {
            e.Cancel = true;

            return;
        }

        AdornmentToEdit.Thickness = new (AdornmentToEdit.Thickness.Left, AdornmentToEdit.Thickness.Top, AdornmentToEdit.Thickness.Right, e.NewValue);
    }
}