using System;
using System.Collections.Generic;
using System.ComponentModel;

namespace Be.Timvw.Framework.ComponentModel
{
    public class FilterList<T> : SortableBindingList<T>
    {
        readonly List<T> allItems = new List<T>();

        public FilterList()
        {
        }

        public FilterList(IEnumerable<T> elements)
            : base(elements)
        {
            this.allItems.AddRange(elements);
        }

        public void Filter(Predicate<T> filter)
        {
            if (ReferenceEquals(filter, null))
            {
                throw new ArgumentNullException("filter");
            }

            this.ApplyFilter(filter);
            if (this.IsSortedCore)
            {
                this.ApplySortCore(this.SortPropertyCore, this.SortDirectionCore);
            }
            OnListChanged(new ListChangedEventArgs(ListChangedType.Reset, -1));
        }

        protected virtual void ApplyFilter(Predicate<T> filter)
        {
            var wantedItems = this.allItems.FindAll(filter);
            
            this.Items.Clear();
            foreach (var item in wantedItems)
            {
                this.Items.Add(item);
            }
        }

        protected override void InsertItem(int index, T item)
        {
            base.InsertItem(index, item);
            allItems.Add(this[index]);
        }

        protected override void RemoveItem(int index)
        {
            allItems.Remove(this[index]);
            base.RemoveItem(index);
        }

        protected override void ClearItems()
        {
            base.ClearItems();
            allItems.Clear();
        }

        protected override void SetItem(int index, T item)
        {
            allItems[allItems.IndexOf(this[index])] = item;
            base.SetItem(index, item);
        }
    }
}