using Avalonia.Controls;
using Avalonia.Controls.Models.TreeDataGrid;
using ReactiveUI;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Linq;

namespace Example;


public class MainViewModel : ReactiveObject
{

    private readonly ExampleCollection _collection = new();

    public MainViewModel()
    {
        Source = new FlatTreeDataGridSource<string>(_collection)
        {
            Columns =
            {
                new TextColumn<string, string>("Value", x => x),
            },
        };
    }

    public FlatTreeDataGridSource<string> Source { get; }

    public void Test()
    {
        _collection.ReplaceRange(5, 2, ["new1", "new2", "new3"]);
    }

}


public class ExampleCollection : IEnumerable<string>, IList, INotifyCollectionChanged
{

    private readonly List<string> _items = new(Enumerable.Range(0, 500).Select(item => item.ToString()));

    public event NotifyCollectionChangedEventHandler? CollectionChanged;

    public object? this[int index] { get => _items[index]; set => _items[index] = (string)value!; }

    public int Count => _items.Count;

    public void ReplaceRange(int index, int count, string[] newItems)
    {
        string[] oldItems = _items.Skip(index).Take(count).ToArray();
        _items.RemoveRange(index, count);
        _items.InsertRange(index, newItems);
        CollectionChanged?.Invoke(this, new(NotifyCollectionChangedAction.Replace, newItems, oldItems, index));
    }

    // not needed for example
    public bool IsFixedSize => false;
    public bool IsReadOnly => false;
    public bool IsSynchronized => false;
    public object SyncRoot => null!;
    public int Add(object? value) => throw new NotImplementedException();
    public void Clear() => throw new NotImplementedException();
    public bool Contains(object? value) => throw new NotImplementedException();
    public void CopyTo(Array array, int index) => throw new NotImplementedException();
    public IEnumerator GetEnumerator() => throw new NotImplementedException();
    public int IndexOf(object? value) => throw new NotImplementedException();
    public void Insert(int index, object? value) => throw new NotImplementedException();
    public void Remove(object? value) => throw new NotImplementedException();
    public void RemoveAt(int index) => throw new NotImplementedException();
    IEnumerator<string> IEnumerable<string>.GetEnumerator() => throw new NotImplementedException();
}