Item-Level Presentation Models for WPF

using System;
using System.Collections.Generic;
using HappyNomad.PresentationModel;
using HappyNomad.Outlining;

namespace HappyNomad.Examples.PresentationModel.GUI.Model {

	public sealed class Demo3ItemView : HierarchicalPresentationModel<SampleItem,Demo3ItemView> {

		#region Object Creation

		/// <summary>Creates a root-level Demo3ItemView.</summary>
		public Demo3ItemView()
		  : base( new Representative("Root"), App.SampleListContainer.SampleList, false, false, true ) { }

		/// <summary>
		/// Creates a Demo3ItemView that does not (yet) have any sub-items.
		/// </summary>
		/// <param name="domainItem">The sample item to be represented by this node</param>
		private Demo3ItemView( SampleItem domainItem ) : base( domainItem, null, false, false, true ) { }

		/// <inheritdoc/>
		protected override Demo3ItemView CreateInstance( SampleItem domainItem ) {
			return new Demo3ItemView( domainItem );
		}

		#endregion

		#region 'DesiredPosition' Method

		/// <inheritdoc/>
		protected override RelativePosition<Demo3ItemView> DesiredPosition( SampleItem itemToAdd ) {

			Represented represented = itemToAdd as Represented;
			if ( represented != null && represented.RepresentedBy != null ) { //If it's represented...
				Demo3ItemView representativeWrapper =
					FindDescendant( represented.RepresentedBy ); //Is the representative also related?
				if ( representativeWrapper != null ) { //If related...
					//representativeWrapper.subItems.Add( itemToAdd ); //then add as sub-item of representative
					return new RelativePosition<Demo3ItemView>(
					  OutliningCommands.NewChild, representativeWrapper, null );
				}
			}

			Representative representative = itemToAdd as Representative;
			if ( representative != null ) { //If it's a representative...
				IList<Demo3ItemView> itemsRepresented =
					ItemsRepresented( representative ); //Are any of its represented items present?
				if ( itemsRepresented.Count > 0 ) { //If present, then insert as parent of represented items:
					return new RelativePosition<Demo3ItemView>(
					  OutliningCommands.NewParent, this, itemsRepresented );
				}
			}

			//subItems.Add( itemToAdd );
			return new RelativePosition<Demo3ItemView>( OutliningCommands.NewChild, this, null );
		}

		private IList<Demo3ItemView> ItemsRepresented( Representative representative ) {
			List<Demo3ItemView> result = new List<Demo3ItemView>();
			foreach ( Demo3ItemView wrapper in subItems ) {
				Represented represented = wrapper.DomainItem as Represented;
				if ( represented != null && represented.RepresentedBy != null && represented.RepresentedBy.Equals( representative ) )
					result.Add( wrapper );
			}
			return result;
		}

		#endregion

		public Representative RepresentedBy {
			get {
				Represented represented = DomainItem as Represented;
				if ( represented != null ) return represented.RepresentedBy;
				else return null;
			}
			set {
				Represented represented = DomainItem as Represented;
				if ( represented != null ) represented.RepresentedBy = value;
			}
		}
	}
}