using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;

namespace Auspex.Vfx.Internal;

internal sealed class FrameLifetimeTracker<T> : IDisposable where T : IDisposable
{
	private Dictionary<(string, string), T> prevActive;

	private Dictionary<(string, string), T> currActive;

	internal FrameLifetimeTracker()
	{
		prevActive = new Dictionary<(string, string), T>();
		currActive = new Dictionary<(string, string), T>();
	}

	internal bool IsTouched((string, string) key)
	{
		return currActive.ContainsKey(key);
	}

	internal bool TryTouchExisting((string, string) key, [MaybeNullWhen(false)] out T o)
	{
		if (prevActive.TryGetValue(key, out o))
		{
			prevActive.Remove(key);
			currActive.Add(key, o);
			return true;
		}
		return false;
	}

	internal void TouchNew((string, string) key, T t)
	{
		currActive.Add(key, t);
	}

	internal bool Remove((string, string) key)
	{
		if (currActive.Remove(key, out var value))
		{
			value.Dispose();
			return true;
		}
		if (prevActive.Remove(key, out var value2))
		{
			value2.Dispose();
			return true;
		}
		return false;
	}

	public void Update()
	{
		foreach (KeyValuePair<(string, string), T> item in prevActive)
		{
			item.Value.Dispose();
		}
		prevActive.Clear();
		Dictionary<(string, string), T> dictionary = prevActive;
		prevActive = currActive;
		currActive = dictionary;
	}

	internal void ForEachActive(Action<T> action)
	{
		foreach (KeyValuePair<(string, string), T> item in prevActive)
		{
			action(item.Value);
		}
	}

	public void Dispose()
	{
		foreach (KeyValuePair<(string, string), T> item in prevActive)
		{
			item.Value.Dispose();
		}
		foreach (KeyValuePair<(string, string), T> item2 in currActive)
		{
			item2.Value.Dispose();
		}
		GC.SuppressFinalize(this);
	}
}