using System;
using System.Windows;
using System.Windows.Input;
using Caliburn.Messaging;
using Caliburn.Metadata;
using Caliburn.Services;

namespace Caliburn.Actions
{
    public class ActionCommand : ICommand
    {
        #region Fields

        private readonly ActionInfo _actionInfo;
        private readonly Func<object, bool> _canExecute;
        private readonly object _presenter;

        #endregion

        #region Constructor

        public ActionCommand(object presenter, string actionName, Func<object, bool> canExecute)
        {
            _presenter = presenter;
            _canExecute = canExecute;

            PresenterInfo presenterInfo =
                DI.Resolve<IPresenterManager>().GetInfo(_presenter.GetType());

            _actionInfo = presenterInfo.FindAction(actionName);
        }

        public ActionCommand(object presenter, Action<object> action, Func<object, bool> canExecute)
            : this(presenter, action.Method.Name, canExecute)
        {
        }

        #endregion

        #region ICommand Members

        public event EventHandler CanExecuteChanged
        {
            add { CommandManager.RequerySuggested += value; }
            remove { CommandManager.RequerySuggested -= value; }
        }

        public void Execute(object parameter)
        {
            ActionMessage message = new ActionMessage();

            Parameter p = new Parameter();
            p.Value = parameter;
            message.Parameters.Add(p);

            _actionInfo.Execute(_presenter, message, parameter as DependencyObject);
        }

        public bool CanExecute(object parameter)
        {
            if(_canExecute != null)
                return _canExecute(parameter);
            else return true;
        }

        #endregion
    }
}