using System;
using System.Collections.Generic;

namespace Syntriax.Engine.Core;

public class Pool<T> : IPool<T>
{
    public Event<IPool<T>, T> OnRemoved { get; } = new();
    public Event<IPool<T>, T> OnReturned { get; } = new();

    private readonly Func<T> generator = null!;
    private readonly Queue<T> queue = new();

    public T Get()
    {
        if (!queue.TryDequeue(out T? result))
            result = generator();

        OnRemoved?.Invoke(this, result);
        return result;
    }

    public void Return(T item)
    {
        if (queue.Contains(item))
            return;

        queue.Enqueue(item);
        OnReturned?.Invoke(this, item);
    }

    public Pool(Func<T> generator, int initialCapacity = 1)
    {
        this.generator = generator;
        for (int i = 0; i < initialCapacity; i++)
            queue.Enqueue(generator());
    }
}