using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Collections.Specialized;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Tango.SharedUI.Components
{
    public class SelectedObjectCollection<T> : ObservableCollection<SelectedObject<T>>
    {
        public event EventHandler SelectionChanged;
        public ObservableCollection<T> Source { get; set; }
        public ObservableCollection<T> SynchedSource { get; set; }

        public SelectedObjectCollection(ObservableCollection<T> source, ObservableCollection<T> synchedSource)
        {
            SynchedSource = synchedSource;
            Source = source;

            foreach (var item in source)
            {
                var selectedItem = new SelectedObject<T>(item, synchedSource.Contains(item));
                this.Add(selectedItem);
                selectedItem.IsSelectedChanged += SelectedItem_IsSelectedChanged;
            }
        }

        private void SelectedItem_IsSelectedChanged(object sender, EventArgs e)
        {
            SelectedObject<T> item = sender as SelectedObject<T>;
            
            if (item.IsSelected)
            {
                if (!SynchedSource.Contains(item.Data))
                {
                    SynchedSource.Add(item.Data);
                }
            }
            else
            {
                SynchedSource.Remove(item.Data);
            }

            SelectionChanged?.Invoke(this, new EventArgs());
        }
    }
}