namespace Netron.Diagramming.Core {
  /// <summary>
  /// Ungroup command
  /// </summary>
  class UngroupCommand : Command {
    #region Fields
    IBundle bundle;
    IController controller;
    IGroup mGroup;
    #endregion

    #region Properties
    /// <summary>
    /// Gets the newly created group after <see cref="Redo"/> was called
    /// </summary>
    public IGroup Group {
      get { return mGroup; }
    }

    /// <summary>
    /// Gets the entities.
    /// </summary>
    /// <value>The shape.</value>
    public CollectionBase<IDiagramEntity> Entities {
      get { return bundle.Entities; }
    }

    #endregion

    #region Constructor
    /// <summary>
    /// Initializes a new instance of the <see cref="T:UngroupCommand"/> class.
    /// </summary>
    /// <param name="controller">The controller.</param>
    /// <param name="group">The group.</param>
    public UngroupCommand(IController controller, IGroup group)
      : base(controller) {
      this.Text = "Ungroup";
      this.controller = controller;
      this.mGroup = group;
      bundle = new Bundle();
    }
    #endregion

    #region Methods

    /// <summary>
    /// Perform redo of this command.
    /// </summary>
    public override void Redo() {
      //remove the group from the layer
      this.Controller.Model.DefaultPage.DefaultLayer.Entities.Remove(mGroup);
      //detach the entities from the group
      foreach (IDiagramEntity entity in mGroup.Entities) {
        //this will be recursive if an entity is itself an IGroup
        entity.Group = null;
        bundle.Entities.Add(entity);
        //mGroup.Entities.Remove(entity);
        Controller.Model.AddEntity(entity);
      }
      //change the visuals such that the entities in the group are selected

      CollectionBase<IDiagramEntity> col = new CollectionBase<IDiagramEntity>();
      col.AddRange(mGroup.Entities);

      this.Controller.Model.Selection.SelectedItems = col;

      mGroup.Invalidate();
      mGroup = null;

      //note that the entities have never been disconnected from the layer
      //so they don't have to be re-attached to the anything.
      //The insertion of the Group simply got pushed in the scene-graph.


    }

    /// <summary>
    /// Perform undo of this command.
    /// </summary>
    public override void Undo() {

      //create a new group
      GroupShape group = new GroupShape(this.Controller.Model);
      //asign the entities to the group
      group.Entities = bundle.Entities;

      foreach (IDiagramEntity entity in group.Entities) {
        //this will be recursive if an entity is itself an IGroup
        entity.Group = group;
      }
      //add the new group to the layer
      this.Controller.Model.DefaultPage.DefaultLayer.Entities.Add(group);

      mGroup = group;

      //select the newly created group
      CollectionBase<IDiagramEntity> col = new CollectionBase<IDiagramEntity>();
      col.Add(mGroup);
      this.Controller.Model.Selection.SelectedItems = col;
      mGroup.Invalidate();


    }


    #endregion
  }

}