using System;
using System.Diagnostics;
using System.Collections.Concurrent;
using System.Threading;
using UnityEngine;
/// <summary>
/// Unity主线程工作队列
/// </summary>
public class UnityWorkQueue : MonoBehaviour
{
    private Thread _mainAppThread = null;
    private readonly ConcurrentQueue<Action> _mainThreadWorkQueue = new ConcurrentQueue<Action>();

    public bool IsMainAppThread
    {
        get
        {
            UnityEngine.Debug.Assert(_mainAppThread != null, "This method can only be called once the object is awake.");
            return Thread.CurrentThread == _mainAppThread;
        }
    }

    [Conditional("UNITY_ASSERTIONS")]
    public void EnsureIsMainAppThread()
    {
        UnityEngine.Debug.Assert(IsMainAppThread, "This method can only be called from the main Unity application thread.");
    }

    protected virtual void Awake()
    {
        // Awake()方法总是从Unity主线程调用(the main Unity app thread)
        _mainAppThread = Thread.CurrentThread;
    }

    protected virtual void Update()
    {
        if (_mainThreadWorkQueue.TryDequeue(out Action workload))
        {
            workload();
        }
    }

    public void InvokeOnAppThread(Action action)
    {
        if (_mainAppThread != null && IsMainAppThread)
        {
            action();
        }
        else
        {
            _mainThreadWorkQueue.Enqueue(action);
        }
    }
}