using System;
using System.Collections.Generic;

namespace Sandbox.Polygons;

public abstract class Pooled<T> : IDisposable
    where T : Pooled<T>, new()
{
#pragma warning disable SB3000
    private const int MaxPoolCount = 64;
    private static List<T> Pool { get; } = new();
#pragma warning restore SB3000

    public static T Rent()
    {
        lock ( Pool )
        {
            if ( Pool.Count <= 0 ) return new T();

            var writer = Pool[^1];
            Pool.RemoveAt( Pool.Count - 1 );

            writer._isInPool = false;
            writer.Reset();

            return writer;
        }
    }

    public void Return()
    {
        lock ( Pool )
        {
            if ( _isInPool ) throw new InvalidOperationException( "Already returned." );

            Reset();

            _isInPool = true;

            if ( Pool.Count < MaxPoolCount ) Pool.Add( (T) this );
        }
    }

    private bool _isInPool;

    public abstract void Reset();

    public void Dispose()
    {
        Return();
    }
}