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

// 角色状态机
[DisallowMultipleComponent]
public class UnitState : UnitComponent
{
    public enum EUnitState
    {
		Nien, 

        Idle 	   ,
        Move 	  ,
        Spawn 	  ,
        Die 	  ,
        Dead 	  ,
        Skill 	  ,
        // 		  
        HitAir 	  ,
        HitAirHit ,
        Knockdown ,
        //		  
        HitGuard  ,
        //		  
        Walk	  ,
		// 		  
		Rise	  ,
		// 		  
		Jump	  ,
		// 转身   
		Turn ,
        Landing ,   // 从空中降落
    }

    [SerializeField] private EUnitState m_State;
    public EUnitState CurrentState { get { return m_State; } }

	public override void Initialize()
	{
		base.Initialize();

		InitState(); 
	}

	#region state param
	public struct IdleParam {}

    public struct MoveParam
    {
		public bool isRight;
		public string key;
    }

    public struct SkillParam
    {

    }

	public struct JumpParam
	{ }

	public struct TurnParam
	{
		EUnitState nextState;
	}

    public struct LandingParam { }

    #endregion  

    void InitState()
    {
	}

	public void ChangeState<T>(EUnitState nextState, T param = default, bool bForce = false)
    {
        if (!IsChange(nextState, bForce))
            return;

		LogHelper.Log("UnitState: " + m_State.ToString() + " -> " + nextState.ToString());

		StopAllCoroutines();

		EUnitState prevState = m_State;
        string methodFunc = "On" + m_State.ToString() + "Exit";
        MethodInfo exitMethod = GetType().GetMethod(methodFunc, BindingFlags.Instance | BindingFlags.NonPublic, null, new Type[] { typeof(EUnitState) }, null);
        if(exitMethod != null)
        {
            exitMethod.Invoke(this, new object[] { nextState });
        }
        else
        {
            LogHelper.LogError("缺少 " + methodFunc);
        }
        m_State = nextState;

		StartCoroutine(m_State.ToString(), param);
	}

	bool IsChange(EUnitState newState, bool bForce)
    {
        if (newState != m_State || bForce)
            return true;
        return false;
    }

	IEnumerator Nein() { yield break; }
	void OnNienExit(EUnitState nextState) { }

	#region Idle

	IEnumerator Idle(IdleParam param)
    {
        if(m_Owner.isInAir) // 浮空切换到landing
        {

        }
		else // idle
		{
			m_Owner.SetYPosition(0);
			m_Owner.unitAnimation.AnimIdle();
			while (true)
			{
				if (Input.GetKeyDown("j"))
				{
					ChangeState(EUnitState.Skill, new SkillParam());
				}
				if (Input.GetKeyDown("space"))
				{
					ChangeState(EUnitState.Jump, new JumpParam());
				}
				if (Input.GetKey("d"))
				{
					InputManager.Instance.OnMoveRight();
				}
				if (Input.GetKey("a"))
				{
					InputManager.Instance.OnMoveLeft();
				}
				yield return null;
			}
		}
	}

    void OnIdleExit(EUnitState nextState)
    {
		m_Owner.unitAnimation.animator.ResetTrigger("ToIdle");
    }
    #endregion

    #region Move 
	IEnumerator Move(MoveParam param)
    {
		if (m_Owner.isTowardRight && !param.isRight
		|| !m_Owner.isTowardRight && param.isRight)
		{
			//m_Owner.unitAnimation.Play(UnitAnimation.EAnimState.Turn);
			//yield return new WaitForActionReachEnd(m_Owner.unitAnimation);
			//if (param.isRight)
			//	m_Owner.transform.rotation = Quaternion.Euler(0, 0, 0);
			//else
			//	m_Owner.transform.rotation = Quaternion.Euler(0, 180, 0);
			m_Owner.transform.rotation = Quaternion.Euler(0, param.isRight ? 0 : 180, 0);
		}
        //if (Input.GetKey(param.key))
        m_Owner.unitAnimation.AnimMove();
		while (Input.GetKey(param.key))
		{
			yield return null;
		}
		ChangeState(EUnitState.Idle, new IdleParam());
    }

    void OnMoveExit(EUnitState nextState)
    {
        m_Owner.unitAnimation.animator.ResetTrigger("ToMove");
    }

	#endregion

	#region Skill

	IEnumerator Skill(SkillParam param)
	{
		m_Owner.unitAnimation.AnimAttack();
        yield return new WaitForTransitionDone(m_Owner.unitAnimation); 
        yield return new WaitForActionReachEnd(m_Owner.unitAnimation);
		ChangeState(EUnitState.Idle, new IdleParam());
	}

	void OnSkillExit(EUnitState next)
	{

	}

	#endregion

	#region Jump 

	IEnumerator Jump(JumpParam param)
	{
		while(true)
		{
			// 空中连击
			if(Input.GetKeyDown("j"))
			{
				SkillParam skill = new SkillParam();
				ChangeState(EUnitState.Skill, skill);
			}
			yield return null;
		}
	}

	void OnJumpExit(EUnitState next)
	{

	}

    #endregion

    #region Landing

    IEnumerator Landing(LandingParam param)
    {
        yield return new WaitForLanding(m_Owner);
        Vector3 pos = m_Owner.transform.position;
        pos.y = 0;
        m_Owner.transform.position = pos;
        ChangeState<IdleParam>(EUnitState.Idle);
    }

    void OnLandingExit(EUnitState next)
    {
    }

    #endregion

}