using System.Windows;
using Caliburn.Metadata;
using Caliburn.Presenters;
using Caliburn.Services;

namespace Caliburn.Controls
{
    public class PresenterHost : TransitionPresenter
    {
        #region Fields

        public static readonly DependencyProperty PresenterProperty =
            DependencyProperty.Register(
                "Presenter",
                typeof(object),
                typeof(PresenterHost),
                new PropertyMetadata(PresenterChanged)
                );

        #endregion

        #region Properties

        public object Presenter
        {
            get { return GetValue(PresenterProperty); }
            set { SetValue(PresenterProperty, value); }
        }

        #endregion

        #region Event Handlers

        private static void PresenterChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            if(e.OldValue != e.NewValue)
            {
                IPresenterManager presenterManager = DI.Resolve<IPresenterManager>();
                PresenterHost host = (PresenterHost) d;

                if(e.OldValue != null)
                    presenterManager.RemoveBinding(host);

                if(e.NewValue != null)
                {
                    presenterManager.AddBinding(e.NewValue, host);

                    if(host.Content == null)
                    {
                        IHostedPresenter hostedPresenter = e.NewValue as IHostedPresenter;

                        if (hostedPresenter != null && hostedPresenter.CurrentView != null)
                        {
                            host.Content = hostedPresenter.CurrentView;
                        }
                        else
                        {
                            PresenterInfo info = presenterManager.GetInfo(e.NewValue.GetType());
                            DefaultViewAttribute defaultView = info.GetMetadata<DefaultViewAttribute>();

                            if(defaultView != null) host.Content = defaultView.CreateView();
                        }
                    }
                }
            }
        }

        protected override void BeginTransition()
        {
            base.BeginTransition();

            IHostedPresenter hostedPresenter = Presenter as IHostedPresenter;
            if (hostedPresenter != null) hostedPresenter.CurrentView = CurrentContentPresenter.Content;
        }

        #endregion
    }
}