using System;
using System.Windows.Input;

namespace vCloud.GeneratePackages.Tool.ViewModels
{
    public class Command : ViewModel, ICommand
    {
        private readonly Action<object> _executeAction;
        private readonly Func<object, bool> _canExecuteFunc;

        public event EventHandler CanExecuteChanged;

        public Command(string name, Action<object> executeAction, Func<object, bool> canExecuteFunc = null)
        {
            Description = name;
            if (executeAction == null)
            {
                throw new NullReferenceException("Execute Action can not be null");
            }
            _executeAction = executeAction;
            _canExecuteFunc = canExecuteFunc;
        }

        /// <summary>
        /// If this command can executed
        /// </summary>
        /// <param name="parameter"></param>
        /// <returns></returns>
        public bool CanExecute(object parameter)
        {
            if (!IsEnabled)
            {
                return false;
            }

            if (_canExecuteFunc != null)
            {
                return _canExecuteFunc(parameter);
            }
            return true;
        }

        /// <summary>
        /// Execute the command
        /// </summary>
        /// <param name="parameter"></param>
        public virtual void Execute(object parameter)
        {
            if (CanExecute(parameter))
            {
                //Logger.WriteLineInfo($"Execute Command with description {Description}");
                _executeAction(parameter);
            }
        }

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

        protected override void OnIsEnabledChanged()
        {
            OnCanExecuteChanged();
            base.OnIsEnabledChanged();
        }

        internal void UpdateDescription()
        {
            OnPropertyChanged(() => Description);
        }
    }
}