using System;
using System.Windows.Input;

namespace FSI.Lib.MVVM
{
    /// <summary>
    ///     DelegateCommand borrowed from
    ///     http://www.wpftutorial.net/DelegateCommand.html
    /// </summary>
    public class DelegateCommand : ICommand
    {
        private readonly Predicate<object> _canExecute;
        private readonly Action<object> _execute;

        public DelegateCommand(Action<object> execute,
            Predicate<object> canExecute = null)
        {
            _execute = execute;
            _canExecute = canExecute;
        }

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

        #region ICommand Members

        public event EventHandler CanExecuteChanged;

        public bool CanExecute(object parameter)
        {
            return _canExecute == null || _canExecute(parameter);
        }

        public void Execute(object parameter)
        {
            _execute(parameter);
        }

        #endregion
    }
}
