// Copyright © 2017-2026 QL-Win Contributors
//
// This file is part of QuickLook program.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

using System;
using System.Threading.Tasks;
using System.Windows.Input;

namespace QuickLook.Common.Commands;

public class AsyncRelayCommand(Func<Task> execute, Func<bool> canExecute = null) : ICommand
{
    private readonly Func<Task> _execute = execute ?? throw new ArgumentNullException(nameof(execute));
    private readonly Func<bool> _canExecute = canExecute ?? (() => true);
    private bool _isExecuting;

    public bool CanExecute(object parameter)
    {
        return !_isExecuting && _canExecute();
    }

    public async void Execute(object parameter)
    {
        if (!CanExecute(parameter))
            return;

        _isExecuting = true;
        RaiseCanExecuteChanged();
        try
        {
            await _execute();
        }
        finally
        {
            _isExecuting = false;
            RaiseCanExecuteChanged();
        }
    }

    public event EventHandler CanExecuteChanged;

    public void RaiseCanExecuteChanged()
    {
        CanExecuteChanged?.Invoke(this, EventArgs.Empty);
    }
}