/* ElementViewModelBase.cs
 * part of zaaReloaded2
 * 
 * Copyright 2015-2018 Daniel Kraus
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
using System;
using System.Linq;
using zaaReloaded2.Controller.Elements;
using System.Collections.ObjectModel;

namespace zaaReloaded2.ViewModels
{
    public class ControlElementViewModel : ElementViewModel
    {
        #region Properties

        /// <summary>
        /// Gets a collection of child ElementViewModels.
        /// </summary>
        public ObservableCollection<ElementViewModel> Elements { get; protected set; }

        /// <summary>
        /// Gets information whether this control element view model can
        /// have child elements;
        /// </summary>
        public virtual bool CanHaveChildren
        {
            get
            {
                return ((ControlElementBase)Element).CanHaveChildren;
            }
        }

        public override string ToolTip { get { return Element.Label; } }

        #endregion

        #region Constructors

        public ControlElementViewModel() : this(null) { }

        public ControlElementViewModel(ControlElementBase controlElement)
            : base(controlElement)
        {
            Elements = new ObservableCollection<ElementViewModel>();
            if (controlElement != null)
            {
                foreach (FormatElementBase childElement in controlElement.Children)
                {
                    FormatElementViewModel childVM = new FormatElementViewModel(childElement);
                    Elements.Add(childVM);
                }
            }
        }

        /// <summary>
        /// Creates a new instance by copying the Elements property from another
        /// ControlElementViewModel and the Children property from the other
        /// view model's model.
        /// </summary>
        /// <param name="copyFrom">Other ControlElementViewModel to copy
        /// from.</param>
        public ControlElementViewModel(
            ControlElementBase controlElement,
            ControlElementViewModel copyFrom)
            : this(controlElement)
        {
            Elements = copyFrom.Elements;
            ((ControlElementBase)Element).Children = controlElement.Children;
        }

        #endregion

        #region Public methods

        public void AddChildElement(FormatElementViewModel viewModel)
        {
            Elements.Add(viewModel);
            viewModel.Parent = this;
            ControlElementBase e = Element as ControlElementBase;
            e.Children.Add(viewModel.RevealModelObject() as FormatElementBase);
        }

        public void RemoveChildElement(FormatElementViewModel viewModel)
        {
            if (!Elements.Contains(viewModel))
            {
                throw new InvalidOperationException(
                    "Cannot remove child view model that is not in the collection.");
            }
            Elements.Remove(viewModel);
            ((ControlElementBase)Element).Children
                .Remove(viewModel.RevealModelObject() as FormatElementBase);
            viewModel.Parent = null;
        }

        #endregion

        #region Overrides

        public override object Clone()
        {
            ControlElementViewModel clone = new ControlElementViewModel();
            clone.Element = Element;
            clone.Elements = new ObservableCollection<ElementViewModel>(
                Elements.Select(evm => evm.Clone() as ElementViewModel));
            foreach (FormatElementViewModel evm in clone.Elements)
            {
                evm.Parent = clone;
            }
            return clone;
        }

        #endregion
    }
}