using System;
using UnityEngine;// 首先定义一个单例模式类并且也继承MonoBehaviour
public abstract class MonoSingleton<T> : MonoBehaviour where T : MonoSingleton<T>
{private static T instance = null; //单例模式变量public static T Instance          //变量get方法
    {get{if (instance != null) return instance; //空判断Type type = typeof(T);                 // T localInstance = GameObject.FindObjectOfType(type) as T; // 检测实例是否存在if (localInstance == null){string typeName = type.ToString();var gameObject = new GameObject(typeName, type);localInstance = gameObject.GetComponent<T>();if (localInstance == null)Debug.LogError("Problem during the creation of " + typeName, gameObject);elseInitialize(localInstance);}return instance;}}// 第一次创建的时候 对创建类进行一下关联的初始化private static void Initialize(T localInstance){if (instance == null){instance = localInstance;instance.OnInitialize();OnInstanceReady();}else if (instance != localInstance){DestroyImmediate(localInstance.gameObject); //如果创建的类和存在的类不一致 则立即收回资源
        }}protected virtual void Awake()        // 虚函数 创建实例的类 挂在对象加载时 如果不重写Awake方法 单例实例会被立刻创建
    {Initialize(this as T);}private void OnApplicationQuit()      // 销毁的执行顺序  OnApplicationQuit OnDisable OnDestroy
    {Destroyed(this as T);}private void OnDisable(){Destroyed(this as T);}private void OnDestroy(){Destroyed(this as T);}private static void Destroyed(T localInstance){if (instance == localInstance){instance.OnFinalize();instance = null;}}public virtual void OnInitialize() {} //虚函数 创建实例的类 创建时可以重写此方法 创建后可执行初始化public virtual void OnFinalize() {}   //虚函数 创建实例的类 创建时可以重写此方法 销毁对象之前会调用///public static bool Exists{get { return instance != null; }}public static bool IsInstanceReady{get { return instance != null; }}//单例被创建后 调用Event事件进行相应处理 /////public static event EventHandler InstanceReady;private static void OnInstanceReady(){var handler = InstanceReady;if (handler != null)handler(null, EventArgs.Empty);}
}

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using System;
public class Scheduler : MonoSingleton<Scheduler>
{private Queue<Action> tasks = new Queue<Action>(); // Queue（队列）类主要实现了一个FIFO（First In First Out，先进先出）的机制 //1. 挂在对象启动后 实例化单例模式    //2. 当加载一个新关卡时，所有场景中所有的物体被销毁，然后新关卡中的物体被加载进来。    //   为了保持在加载新关卡时物体不被销毁，使用DontDestroyOnLoad保持，    //   如果物体是一个组件或游戏物体，它的整个transform层次将不会被销毁，全部保留下来。protected virtual void Awake(){base.Awake();DontDestroyOnLoad(this);}public void Schedule(Action task){if (task == null)return;lock (tasks)tasks.Enqueue(task);}public Coroutine AwaitNextFrame(Action onDone){if (onDone == null)return null;return StartCoroutine(AwaitNextFrameInternal(onDone));}public Coroutine AwaitForSeconds(float seconds, Action onDone){if (seconds < 0.0f || onDone == null)return null;return StartCoroutine(x => x.Return = new WaitForSeconds(seconds),x => onDone());}public Coroutine While(Func<bool> statement, Action onDone){if (statement == null || onDone == null)return null;return StartCoroutine(RunWhile(statement, onDone));}public Coroutine StartCoroutine(params Func<object>[] statements){if (statements.Length == 0)return null;return StartCoroutine(RunStatements(statements));}public Coroutine StartCoroutine(params Action<ReturnValue>[] statements){if (statements.Length == 0)return null;return StartCoroutine(RunStatements(statements));}// === privates ================================================================private void Update(){lock (tasks){int throttle = 15;while (tasks.Count > 0 && throttle > 0){tasks.Dequeue()();throttle--;}}}private static IEnumerator RunStatements(Func<object>[] statements){foreach (var statement in statements){var st = statement();if (st is IEnumerator)yield return Scheduler.Instance.StartCoroutine((IEnumerator)st);elseyield return st;}}private static IEnumerator RunStatements(Action<ReturnValue>[] statements){foreach (var statement in statements){var param = new ReturnValue();statement(param);if (param.Return is IEnumerator)yield return Scheduler.Instance.StartCoroutine((IEnumerator)param.Return);elseyield return param.Return;}}private static IEnumerator RunWhile(Func<bool> statement, Action onDone){while (statement())yield return null;onDone();}private static IEnumerator AwaitNextFrameInternal(Action callback){yield return null;callback();}public class ReturnValue{public object Return;}
}

Scheduler.Instance.StartCoroutine(InitializeBattleAsync());

private IEnumerator InitializeBattleAsync()
{battleCharacterManager = new BattleCharacterManager();yield return battleCharacterManager.CreateRawGameObject(new CharacterCreationInfo(CharacterType.Summon, CharacterClass.SummonDragon),go =>{summon = go;                   //托管 第五步执行summon.SetActive(false);});
}

public class BattleCharacterManager : IBattleCharacterManager
{    // 逻辑函数第二步调用 CreateOneCharacterInstanceAsync 执行结束后返回public YieldInstruction CreateRawGameObject(CharacterCreationInfo characterCreationInfo, Action<GameObject> whenDone){return Scheduler.Instance.StartCoroutine(CreateOneCharacterInstanceAsync(characterCreationInfo, whenDone));}    // 逻辑处理函数第三部调用 private IEnumerator CreateOneCharacterInstanceAsync(CharacterCreationInfo info, Action<GameObject> whenDone){if (whenDone == null)throw new ArgumentNullException("whenDone");UnityEngine.Object prefab = null;if (characterPrefabs.TryGetValue(info.CharacterClass, out prefab) == false){var basePath = BattleConstants.CharacterConstants.CharacterPrefabsPath;if (info.CharacterType == CharacterType.Summon)basePath = BattleConstants.CharacterConstants.SummonPrefabsPath;var prefabFullPath = basePath + ResolvePrefabName(info);var resourceRequest = Resources.LoadAsync(prefabFullPath);yield return resourceRequest;yield return null;prefab = resourceRequest.asset;if (prefab == null)throw new InvalidOperationException("Impossible to find prefab '" + prefabFullPath + "'");characterPrefabs.Add(info.CharacterClass, prefab);}var instance = GameObject.Instantiate(prefab) as GameObject;if (instance == null)throw new InvalidOperationException("Impossible to create instance of prefab '" + info.CharacterClass + "'");        // 托管执行whenDone(instance);}
}

void battleWin
{SceneManager.Instance.RootStateMachine.PerformAction(RootActionTokens.Next);// result win
    Scheduler.Instance.StartCoroutine(x => x.Return = new WaitForSeconds(0.5f),x => BattleResult.Instance.BattleWin());return;
}

 private void RunAwaiter(CharacterAnimationStates state, Action whenDone){Scheduler.Instance.While(        () =>{if (previousState != state){RequestAction(state);return true;}return false;},() =>{if (whenDone != null)whenDone();});}

public void UnloadCurrentMap()
{Scheduler.Instance.AwaitNextFrame(        () =>{OnMapUnloaded(new MapEventArgs(CurrentStage, StartPositions));CurrentStage = Stages.None;});
}