using System;
using System.Collections.Generic;

namespace Goo;

// Auto-keying loop helper: AddRange runs the builder once per item and keys by index when the builder leaves Key == null. User-supplied keys win.
public static class ChildrenExtensions
{
    public static void AddRange<T>(
        this Children                children,
        IReadOnlyList<T>             items,
        Func<int, T, Container>      builder )
    {
        for ( int i = 0; i < items.Count; i++ )
        {
            var child = builder( i, items[i] );
            if ( child.Key is null )
                child = child with { Key = $"_idx:{i}" };
            children.Add( child );
        }
    }
}