using System;
using System.Linq;
using System.Collections;
using System.Threading.Tasks;
using System.Collections.Generic;

using UnityEngine;
using UnityEngine.SceneManagement;

public class GameSystem : MonoBehaviour
{
    public static GameSystem Instance { get; private set; }
    public List<IGameComponent> gameComponents { get; private set; } = new List<IGameComponent>();

    [SerializeField] GameObject[] sigletonComponents;
    public event Action OnSceneLoaded;


    public async void LoadScene(string sceneName)
    {
        var sceneLoadingOperation = SceneManager.LoadSceneAsync(sceneName, LoadSceneMode.Single);
        while(!sceneLoadingOperation.isDone) await Task.Yield();

        OnSceneLoaded?.Invoke();
    }


    public void AddGameComponent(IGameComponent component)
    {
        if(!gameComponents.Contains(component))
            gameComponents.Add(component);
    }

    void Awake()
    {
        foreach(var item in sigletonComponents)
            DontDestroyOnLoad(item.gameObject);

        Instance = this;
    }

    void Start()
    {
        GameSystem[] gameSystems = FindObjectsOfType<GameSystem>();
        if(gameSystems.Length > 1)
        {
            Destroy(this.gameObject);
            return;
        }

        DontDestroyOnLoad(this);
        QRCodeReader.Instance.OnQRCodeRead += LoadScene;
    }

    void Update()
    {
        Parallel.ForEach(gameComponents,
            component => component.OnUpdate());
    }

    void FixedUpdate()
    {
        Parallel.ForEach(gameComponents,
            component => component.OnFixedUpdate());
    }

    void LateUpdate()
    {
        Parallel.ForEach(gameComponents,
            component => component.OnLateUpdate());
    }

    public void RemoveGameComponent(IGameComponent component)
    {
        if(gameComponents.Contains(component))
            gameComponents.Remove(component);
    }
}