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

namespace Uigenx
{
    /// <summary>
    /// Owns a group of subscriptions so a screen can tear everything down in one call. Disposal is
    /// idempotent and one faulty entry never stops the rest.
    /// </summary>
    public sealed class UgxDisposableSet : IDisposable
    {
        readonly List<IDisposable> _items;

        public UgxDisposableSet(int capacity = 4) => _items = new List<IDisposable>(capacity < 1 ? 1 : capacity);

        public int Count => _items.Count;

        public IDisposable Add(IDisposable item)
        {
            if (item != null) _items.Add(item);
            return item;
        }

        public void Dispose()
        {
            for (int i = _items.Count - 1; i >= 0; i--)
            {
                try
                {
                    _items[i].Dispose();
                }
                catch (Exception e)
                {
                    Debug.LogError("[ugx] disposing a subscription threw: " + e);
                }
            }
            _items.Clear();
        }
    }
}