PkmnLibSharp/PkmnLibSharp/Utilities/ReadOnlyArray.cs

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

namespace PkmnLibSharp.Utilities
{
    internal static class CollectionHelper
    {
        internal static ReadOnlyArray<T> ToReadOnly<T>(this IList<T> arr)
        {
            return new ReadOnlyArray<T>(arr);
        }
    }
    
    public class ReadOnlyArray<T> : IReadOnlyList<T>
    {
        private readonly IList<T> _arr;

        public ReadOnlyArray(IList<T> arr)
        {
            _arr = arr;
        }

        public IEnumerator<T> GetEnumerator()
        {
            return _arr.GetEnumerator();
        }

        IEnumerator IEnumerable.GetEnumerator()
        {
            return GetEnumerator();
        }

        public int Count => _arr.Count;
        public T this[int index] => _arr[index];

        public int IndexOf(T item)
        {
            return _arr.IndexOf(item);
        }
        
        public int IndexOf(Func<T, bool> predicate)
        {
            for (var index = 0; index < _arr.Count; index++)
            {
                var a = _arr[index];
                if (predicate(a))
                {
                    return index;
                }
            }
            return -1;
        }

    }
}