ShrlAlgoToolkit/WPFluent/Controls/TitleBar/TitleBarButton.cs




using WPFluent.Extensions;
using WPFluent.Interop;

using System.Windows.Automation.Peers;
using System.Windows.Automation.Provider;

// ReSharper disable once CheckNamespace
namespace WPFluent.Controls;

public class TitleBarButton : Button
{
    /// <summary>
    /// Identifies the <see cref="ButtonsForeground"/> dependency property.
    /// </summary>
    public static readonly DependencyProperty ButtonsForegroundProperty = DependencyProperty.Register(
        nameof(ButtonsForeground),
        typeof(Brush),
        typeof(TitleBarButton),
        new FrameworkPropertyMetadata(SystemColors.ControlTextBrush, FrameworkPropertyMetadataOptions.Inherits));
    /// <summary>
    /// Identifies the <see cref="ButtonType"/> dependency property.
    /// </summary>
    public static readonly DependencyProperty ButtonTypeProperty = DependencyProperty.Register(
        nameof(ButtonType),
        typeof(TitleBarButtonType),
        typeof(TitleBarButton),
        new PropertyMetadata(TitleBarButtonType.Unknown, OnButtonTypeChanged));

    /// <summary>
    /// Identifies the <see cref="MouseOverButtonsForeground"/> dependency property.
    /// </summary>
    public static readonly DependencyProperty MouseOverButtonsForegroundProperty =
        DependencyProperty.Register(
        nameof(MouseOverButtonsForeground),
        typeof(Brush),
        typeof(TitleBarButton),
        new FrameworkPropertyMetadata(null, FrameworkPropertyMetadataOptions.Inherits));

    /// <summary>
    /// Identifies the <see cref="RenderButtonsForeground"/> dependency property.
    /// </summary>
    public static readonly DependencyProperty RenderButtonsForegroundProperty = DependencyProperty.Register(
        nameof(RenderButtonsForeground),
        typeof(Brush),
        typeof(TitleBarButton),
        new FrameworkPropertyMetadata(SystemColors.ControlTextBrush, FrameworkPropertyMetadataOptions.Inherits));

    private readonly Brush _defaultBackgroundBrush = Brushes.Transparent; // REVIEW: Should it be transparent?

    private bool _isClickedDown;
    private User32.WM_NCHITTEST _returnValue;

    public TitleBarButton()
    {
        Loaded += TitleBarButton_Loaded;
        Unloaded += TitleBarButton_Unloaded;
    }

    private void OnButtonsForegroundChanged(object sender, EventArgs e)
    { SetCurrentValue(RenderButtonsForegroundProperty, IsHovered ? MouseOverButtonsForeground : ButtonsForeground); }

    private static void OnButtonTypeChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        if(d is not TitleBarButton titleBarButton)
        {
            return;
        }

        titleBarButton.OnButtonTypeChanged(e);
    }

    private void TitleBarButton_Loaded(object sender, RoutedEventArgs e)
    {
        SetCurrentValue(RenderButtonsForegroundProperty, ButtonsForeground);
        DependencyPropertyDescriptor
            .FromProperty(ButtonsForegroundProperty, typeof(Brush))
            .AddValueChanged(this, OnButtonsForegroundChanged);
    }

    private void TitleBarButton_Unloaded(object sender, RoutedEventArgs e)
    {
        DependencyPropertyDescriptor
            .FromProperty(ButtonsForegroundProperty, typeof(Brush))
            .RemoveValueChanged(this, OnButtonsForegroundChanged);
    }

    protected void OnButtonTypeChanged(DependencyPropertyChangedEventArgs e)
    {
        var buttonType = (TitleBarButtonType)e.NewValue;

        _returnValue = buttonType switch
        {
            TitleBarButtonType.Unknown => User32.WM_NCHITTEST.HTNOWHERE,
            TitleBarButtonType.Help => User32.WM_NCHITTEST.HTHELP,
            TitleBarButtonType.Minimize => User32.WM_NCHITTEST.HTMINBUTTON,
            TitleBarButtonType.Close => User32.WM_NCHITTEST.HTCLOSE,
            TitleBarButtonType.Restore => User32.WM_NCHITTEST.HTMAXBUTTON,
            TitleBarButtonType.Maximize => User32.WM_NCHITTEST.HTMAXBUTTON,
            _ => throw new ArgumentOutOfRangeException(
                "e.NewValue",
                buttonType,
                $"Unsupported button type: {buttonType}."),
        };
    }

    internal bool ReactToHwndHook(User32.WM msg, IntPtr lParam, out IntPtr returnIntPtr)
    {
        returnIntPtr = IntPtr.Zero;

        switch(msg)
        {
            case User32.WM.NCHITTEST:
                if(this.IsMouseOverElement(lParam))
                {
                    /*Debug.WriteLine($"Hitting {ButtonType} | return code {_returnValue}");*/
                    Hover();
                    returnIntPtr = (IntPtr)_returnValue;
                    return true;
                }

                RemoveHover();
                return false;
            case User32.WM.NCMOUSELEAVE: // Mouse leaves the window
                RemoveHover();
                return false;
            case User32.WM.NCLBUTTONDOWN when this.IsMouseOverElement(lParam): // Left button clicked down
                _isClickedDown = true;
                return true;
            case User32.WM.NCLBUTTONUP when _isClickedDown && this.IsMouseOverElement(lParam): // Left button clicked up
                InvokeClick();
                return true;
            default:
                return false;
        }
    }

    /// <summary>
    /// Forces button background to change.
    /// </summary>
    public void Hover()
    {
        if(IsHovered)
        {
            return;
        }

        SetCurrentValue(BackgroundProperty, MouseOverBackground);
        if(MouseOverButtonsForeground != null)
        {
            SetCurrentValue(RenderButtonsForegroundProperty, MouseOverButtonsForeground);
        }

        IsHovered = true;
    }

    /// <summary>
    /// Invokes click on the button.
    /// </summary>
    public void InvokeClick()
    {
        if(new ButtonAutomationPeer(this).GetPattern(PatternInterface.Invoke)
            is IInvokeProvider invokeProvider)
        {
            invokeProvider.Invoke();
        }

        _isClickedDown = false;
    }

    /// <summary>
    /// Forces button background to change.
    /// </summary>
    public void RemoveHover()
    {
        if(!IsHovered)
        {
            return;
        }

        SetCurrentValue(BackgroundProperty, _defaultBackgroundBrush);
        SetCurrentValue(RenderButtonsForegroundProperty, ButtonsForeground);

        IsHovered = false;
        _isClickedDown = false;
    }

    /// <summary>
    /// Gets or sets the foreground of the navigation buttons.
    /// </summary>
    public Brush ButtonsForeground
    {
        get => (Brush)GetValue(ButtonsForegroundProperty);
        set => SetValue(ButtonsForegroundProperty, value);
    }

    /// <summary>
    /// Gets or sets the type of the button.
    /// </summary>
    public TitleBarButtonType ButtonType
    {
        get => (TitleBarButtonType)GetValue(ButtonTypeProperty);
        set => SetValue(ButtonTypeProperty, value);
    }

    public bool IsHovered { get; private set; }

    /// <summary>
    /// Gets or sets the foreground of the navigation buttons when moused over.
    /// </summary>
    public Brush MouseOverButtonsForeground
    {
        get => (Brush)GetValue(MouseOverButtonsForegroundProperty);
        set => SetValue(MouseOverButtonsForegroundProperty, value);
    }

    public Brush RenderButtonsForeground
    {
        get => (Brush)GetValue(RenderButtonsForegroundProperty);
        set => SetValue(RenderButtonsForegroundProperty, value);
    }
}