// Copyright (c) 2019 schick Informatik
// Description: Hilfsklasse zur Darstellung von untergeordneten Listen
// im XCeed PropertyGrid
// Idee von der 2. Antwort hier:
// https://stackoverflow.com/questions/36286530/xceed-wpf-propertygrid-show-item-for-expanded-collection

using System;
using System.Collections.Generic;
using System.Linq;
using System.ComponentModel;
using Xceed.Wpf.Toolkit.PropertyGrid.Attributes;
using System.Collections;

namespace ENI2.Util
{

    #region class ENIExpandableIListConverter<T>

    public class ENIExpandableIListConverter<T> : ExpandableObjectConverter
    {

        public override PropertyDescriptorCollection GetProperties(ITypeDescriptorContext context, object value, Attribute[] attributes)
        {
            if (value is IList<T>)
            {
                IList<T> list = value as IList<T>;
                PropertyDescriptorCollection propDescriptions = new PropertyDescriptorCollection(null);
                IEnumerator enumerator = list.GetEnumerator();
                int counter = -1;
                while (enumerator.MoveNext())
                {
                    counter++;
                    propDescriptions.Add(new ListItemPropertyDescriptor<T>(list, counter));

                }
                return propDescriptions;
            }
            else
            {
                return base.GetProperties(context, value, attributes);
            }
        }
    }

    #endregion

    #region class ListItemPropertyDescriptor

    public class ListItemPropertyDescriptor<T> : PropertyDescriptor
    {
        private readonly IList<T> _owner;
        private readonly int index;

        public ListItemPropertyDescriptor(IList<T> owner, int index) : base("[" + index + "]", null)
        {
            this._owner = owner;
            this.index = index;

        }

        public override AttributeCollection Attributes
        {
            get
            {
                var attributes = TypeDescriptor.GetAttributes(GetValue(null), false);
                //If the Xceed expandable object attribute is not applied then apply it
                if (!attributes.OfType<ExpandableObjectAttribute>().Any())
                {
                    attributes = AddAttribute(new ExpandableObjectAttribute(), attributes);
                }

                //set the xceed order attribute
                return AddAttribute(new PropertyOrderAttribute(index), attributes);
            }
        }

        private AttributeCollection AddAttribute(Attribute newAttribute, AttributeCollection oldAttributes)
        {
            Attribute[] newAttributes = new Attribute[oldAttributes.Count + 1];
            oldAttributes.CopyTo(newAttributes, 1);
            newAttributes[0] = newAttribute;

            return new AttributeCollection(newAttributes);
        }

        public override bool CanResetValue(object component)
        {
            return false;
        }

        public override object GetValue(object component)
        {
            return Value;
        }

        private T Value
          => _owner[index];

        public override void ResetValue(object component)
        {
            throw new NotImplementedException();
        }

        public override void SetValue(object component, object value)
        {
            _owner[index] = (T)value;
        }

        public override bool ShouldSerializeValue(object component)
        {
            return false;
        }

        public override Type ComponentType
          => _owner.GetType();

        public override bool IsReadOnly
          => false;

        public override Type PropertyType
          => Value?.GetType();
    }

    #endregion

    #region class TypeDecorationManager

    public static class TypeDecorationManager
    {
        public static void AddExpandableObjectConverter(Type T)
        {
            TypeDescriptor.AddAttributes(T, new TypeConverterAttribute(typeof(ExpandableObjectConverter)));
            TypeDescriptor.AddAttributes(T, new ExpandableObjectAttribute());
        }

        public static void AddExpandableIListConverter<I>(Type T)
        {
            TypeDescriptor.AddAttributes(T, new TypeConverterAttribute(typeof(ENIExpandableIListConverter<I>)));
            TypeDescriptor.AddAttributes(T, new ExpandableObjectAttribute());
        }
    }

    #endregion

}