using System.Collections.Concurrent;
using System.Threading.Tasks;
using UnityEngine;
using System;

public class UnityMainThreadDispatcher : MonoBehaviour
{
    private static UnityMainThreadDispatcher instance;
    private readonly ConcurrentQueue<Action> actionQueue = new ConcurrentQueue<Action>();


    public static void Initialize()
    {
        if (instance == null)
        {
            var go = new GameObject("UnityMainThreadDispatcher");
            //DontDestroyOnLoad(go);
            instance = go.AddComponent<UnityMainThreadDispatcher>();
        }
    }
    public static UnityMainThreadDispatcher Instance
    {
        get
        {
            if (instance == null)
            {
                var go = new GameObject("UnityMainThreadDispatcher");
                //DontDestroyOnLoad(go);
                instance = go.AddComponent<UnityMainThreadDispatcher>();
            }
            return instance;
        }
    }

    public void Enqueue(Action action)
    {
        actionQueue.Enqueue(action);
    }

    public Task EnqueueAsync(Action action)
    {
        var tcs = new TaskCompletionSource<bool>();

        actionQueue.Enqueue(() =>
        {
            try
            {
                action();
                tcs.SetResult(true);
            }
            catch (Exception e)
            {
                tcs.SetException(e);
            }
        });

        return tcs.Task;
    }

    private void Update()
    {
        while (actionQueue.TryDequeue(out var action))
        {
            action();
        }
    }
}