using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

using XericLibrary.Runtime.Type;

namespace XericLibrary
{
	/// <summary>
	/// 线性处理流程
	/// </summary>
    public class ProgramFlowLinear : WeaklyObject
    {
		#region 委托事件

		/// <summary>
		/// 恢复待执行事件列表
		/// </summary>
		public event Action RecoveredCoroutineList;

		#endregion

		#region 字段属性

		/// <summary>
		/// 设定是否循环处理所有协程
		/// </summary>
		public bool LoopProgramFlow
		{
			get => loopProgramFlow;
			set
			{
				if(TargetEvent == null)
					loopProgramFlow = value;
				else
					Debug.LogError("不允许在协程运行中进行处理流程模式的切换");
			}
		}

		/// <summary>
		/// 循环处理所有协程
		/// </summary>
		private bool loopProgramFlow = true;

		/// <summary>
		/// 最大执行计数
		/// </summary>
		public int MaxEmbeddedLoopCount = 100;

		/// <summary>
		/// 当前协程内执行流程计数
		/// </summary>
		private int embeddedLoopCount = 0;

		/// <summary>
		/// 等待执行的协程
		/// </summary>
		private LinkedList<IEnumerator> routines = new LinkedList<IEnumerator>();

		/// <summary>
		/// 当前执行的协程
		/// </summary>
		private Coroutine TargetEvent;

		/// <summary>
		/// 持久担保者
		/// </summary>
		private MonoBehaviour assure;

		/// <summary>
		/// 第一次执行
		/// </summary>
		private bool firstTime = true;

		#endregion

		/// <summary>
		/// 线性协程处理器，将一系列协程进行线性处理；
		/// </summary>
		/// <param name="recoveredListTodo">将添加协程的过程进行定义</param>
		/// <param name="assure">协程处理的担保脚本</param>
		/// <param name="executeImmediately">在定义完成后立即执行协程</param>
		/// <param name="loopProgram">设定协程循环执行，如果不循环则需要手动调用start方法</param>
		public ProgramFlowLinear(Action recoveredListTodo, MonoBehaviour assure, bool executeImmediately = true, bool loopProgram = true)
		{
			RecoveredCoroutineList = recoveredListTodo;
			this.loopProgramFlow = loopProgram;
			firstTime = true;
			if(executeImmediately)
				StartCoroutine();
		}

		#region 方法

		/// <summary>
		/// 添加待处理协程
		/// </summary>
		/// <param name="routine"></param>
		public void AddCoroutine(IEnumerator routine)
		{
			routines.AddLast(routine);
		}

		/// <summary>
		/// 协程！启动！
		/// </summary>
		public void StartCoroutine()
		{
			if(TargetEvent == null)
			{
				if(firstTime && routines.Count <= 0)
					RecoveredCoroutineList();
				if(routines.Count <= 0)
				{
					Debug.LogError("协程步骤为空，可能是并非初始，或复位栈为空");
					return;
				}
				TargetEvent = assure.StartCoroutine(routines.First.Value);

				routines.RemoveFirst();
				firstTime = false;
			}
		}

		/// <summary>
		/// 执行下一个协程
		/// </summary>
		public void NextCoroutine()
		{
			if(loopProgramFlow && routines.Count <= 0)
				RecoveredCoroutineList();
			if(TargetEvent != null)
				TargetEvent = null;
			else
				Debug.LogError("执行的协程步骤来自初始？");
			StartCoroutine();
		}

		/// <summary>
		/// 尝试增加协程执行计数，当计数超越预设范围后将提示停止协程
		/// </summary>
		public bool TryPromoteEmbedded()
		{
			if(++embeddedLoopCount > MaxEmbeddedLoopCount)
			{
				embeddedLoopCount = 0;
				return true;
			}
			return false;
		}


		#endregion

	}
}