Shaker/Avalonia/Avalonia.Xaml.Interactions/Core/InvokeCommandAction.cs

using System.Diagnostics.Tracing;
using System.Windows.Input;
using Avalonia.Data.Converters;
using CommunityToolkit.Mvvm.Input;

namespace Avalonia.Xaml.Interactions.Core;

/// <summary>
/// Executes a specified <see cref="System.Windows.Input.ICommand"/> when invoked. 
/// </summary>
public class InvokeCommandAction : Interactivity.Action
{
    /// <summary>
    /// Identifies the <seealso cref="Command"/> avalonia property.
    /// </summary>
    public static readonly StyledProperty<ICommand?> CommandProperty =
        AvaloniaProperty.Register<InvokeCommandAction, ICommand?>(nameof(Command));

    /// <summary>
    /// Identifies the <seealso cref="CommandParameter"/> avalonia property.
    /// </summary>
    public static readonly StyledProperty<object?> CommandParameterProperty =
        AvaloniaProperty.Register<InvokeCommandAction, object?>(nameof(CommandParameter));

    /// <summary>
    /// Identifies the <seealso cref="InputConverter"/> avalonia property.
    /// </summary>
    public static readonly StyledProperty<IValueConverter?> InputConverterProperty =
        AvaloniaProperty.Register<InvokeCommandAction, IValueConverter?>(nameof(InputConverter));

    /// <summary>
    /// Identifies the <seealso cref="InputConverterParameter"/> avalonia property.
    /// </summary>
    public static readonly StyledProperty<object?> InputConverterParameterProperty =
        AvaloniaProperty.Register<InvokeCommandAction, object?>(nameof(InputConverterParameter));

    /// <summary>
    /// Identifies the <seealso cref="InputConverterLanguage"/> avalonia property.
    /// </summary>
    /// <remarks>The string.Empty used for default value string means the invariant culture.</remarks>
    public static readonly StyledProperty<string?> InputConverterLanguageProperty =
        AvaloniaProperty.Register<InvokeCommandAction, string?>(nameof(InputConverterLanguage), string.Empty);

    /// <summary>
    /// Gets or sets the command this action should invoke. This is a avalonia property.
    /// </summary>
    public ICommand? Command
    {
        get => GetValue(CommandProperty);
        set => SetValue(CommandProperty, value);
    }

    /// <summary>
    /// Gets or sets the parameter that is passed to <see cref="System.Windows.Input.ICommand.Execute(object)"/>.
    /// If this is not set, the parameter from the <seealso cref="Execute(object, object)"/> method will be used.
    /// This is an optional avalonia property.
    /// </summary>
    public object? CommandParameter
    {
        get => GetValue(CommandParameterProperty);
        set => SetValue(CommandParameterProperty, value);
    }

    /// <summary>
    /// Gets or sets the converter that is run on the parameter from the <seealso cref="Execute(object, object)"/> method.
    /// This is an optional avalonia property.
    /// </summary>
    public IValueConverter? InputConverter
    {
        get => GetValue(InputConverterProperty);
        set => SetValue(InputConverterProperty, value);
    }

    /// <summary>
    /// Gets or sets the parameter that is passed to the <see cref="IValueConverter.Convert"/>
    /// method of <see cref="InputConverter"/>.
    /// This is an optional avalonia property.
    /// </summary>
    public object? InputConverterParameter
    {
        get => GetValue(InputConverterParameterProperty);
        set => SetValue(InputConverterParameterProperty, value);
    }

    /// <summary>
    /// Gets or sets the language that is passed to the <see cref="IValueConverter.Convert"/>
    /// method of <see cref="InputConverter"/>.
    /// This is an optional avalonia property.
    /// </summary>
    public string? InputConverterLanguage
    {
        get => GetValue(InputConverterLanguageProperty);
        set => SetValue(InputConverterLanguageProperty, value);
    }

    /// <summary>
    /// Specifies whether the EventArgs of the event that triggered this action should be passed to the Command as a parameter.
    /// </summary>
    public bool PassEventArgsToCommand { get; set; }

    /// <summary>
    /// Executes the action.
    /// </summary>
    /// <param name="sender">The <see cref="object"/> that is passed to the action by the behavior. Generally this is <seealso cref="Avalonia.Xaml.Interactivity.IBehavior.AssociatedObject"/> or a target object.</param>
    /// <param name="parameter">The value of this parameter is determined by the caller.</param>
    /// <returns>True if the command is successfully executed; else false.</returns>
    public override object Execute(object? sender, object? parameter)
    {
        if (IsEnabled != true || Command is null)
        {
            return false;
        }

        object? resolvedParameter = default;
        if (IsSet(CommandParameterProperty))
        {
            resolvedParameter = CommandParameter;
        }
        else if (InputConverter is not null)
        {
            resolvedParameter = InputConverter.Convert(
                parameter,
                typeof(object),
                InputConverterParameter,
                InputConverterLanguage is not null
                    ? 
                    new System.Globalization.CultureInfo(InputConverterLanguage)
                    : System.Globalization.CultureInfo.CurrentCulture);
        }
        else
        {
            if (PassEventArgsToCommand)
            {
                resolvedParameter = parameter;
            }
        }

        if (!Command.CanExecute(resolvedParameter))
        {
            return false;
        }
        if (Command is IRelayCommand command) command.Execute(sender, resolvedParameter);
        else Command.Execute(resolvedParameter);
        return true;
    }
}