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

//最简单的小怪，碰到玩家自动消失，拥有血量，会自动向主角发动进攻(此时玩家处于红眼状态并减少生命值)
//出生后,会向主角处进行行走,靠近主角时,会停下来(0.1-0.5s),之后跑向主角,发动攻击(攻击完后自动死亡)
//游戏暂停时进入僵持状态（无法受到任何攻击，也不能对玩家造成任何伤害，同时终止行动）
//受到攻击后自身颜色发生变化
public class GhostSouler : Hurtable {
    //数值相关
    //是否碰到玩家
    public bool isTouched;
    //是否死亡
    public bool isDeath;
    //是否暂停
    public bool isPause;
    //怪物的状态(0为行走,1为站立,2为跑步,3为攻击,4为死亡)
    private int status;
    //怪物的各项属性值(攻击力，护甲值，行走速度，奔跑速度)
    public int atk;
    public int def;
    public float runningSpeed;
    public float walkingSpeed;
    //显示或与玩家相关
    private GameObject Player;
    private Player playerScript;
    private float distancePE_;
    private LightShield playerShield_;
    //敌人发动攻击时离玩家的距离
    private float standTimer;
    public float attackDistace;
    //判断攻击对象是不是玩家(不是玩家就是盾牌)
    private bool isAttackedPlayer;
    //敌人最大生命值
    private float maxHp;
    //死亡特效
    public GameObject deathEffect_;


    // Use this for initialization
    void Start() {
        Player = GameObject.FindGameObjectWithTag("Player");
        playerScript = Player.GetComponent<Player>();
        hitEvent.AddListener(GhostAttacked_);
        deathEvent.AddListener(GhostDeath_);
        status = 0;
        standTimer = 0.3f;
        isAttackedPlayer = false;
        myself_1.GetComponent<NavMeshAgent>().speed = walkingSpeed;
        maxHp = hp;
    }

    // Update is called once per frame
    void Update() {
        distancePE_ = CaculatePlayerDistance();
        if (playerScript.enemyDistance > distancePE_ * 4)
        {
            playerScript.enemyDistance = Mathf.Floor(distancePE_) * 8 / 2f;
        }
        if (!isDeath) {
            GhostAlive_();
        }
    }

    //敌人行为相关
    private void GhostBirth_() {

    }
    //原地不动
    private void GhostStand_() {
        myself_1.GetComponent<NavMeshAgent>().destination = myself_1.transform.position;
    }
    //行走
    private void GhostWalk_() {
        myself_1.transform.position += new Vector3(0,0,Mathf.Sin(distancePE_)*0.01f);
        myself_1.GetComponent<NavMeshAgent>().destination = Player.transform.position + Player.GetComponent<CapsuleCollider>().center;
    }
    //跑
    private void GhostRun_() {
        myself_1.GetComponent<NavMeshAgent>().speed = runningSpeed;
        GhostWalk_();
    }
    //攻击玩家
    private void GhostAttack_()
    {
        if (isAttackedPlayer)
        {
            playerScript.Hurted(atk);
            deathEvent.Invoke();
        }
        else
        {
            status = 0;
            standTimer = 0.3f;
            isTouched = false;
            playerShield_.shieldHit();
        }
    }
    //受到攻击
    private void GhostAttacked_() {
        myself_1.GetComponentInChildren<Renderer>().material.color = new Vector4(1.0f, hp / maxHp, hp / maxHp, 1.0f);
    }
    //死亡
    private void GhostDeath_() {
        status = 4;
        isDeath = true;
        Instantiate(deathEffect_);
        deathEffect_.transform.position = myself_1.transform.position;
        int criticalRandom = Random.Range(0, 3);
        if (criticalRandom > 1) {
            playerScript.speedUp();
        }
        Destroy(myself_1);
    }

    //判断距离相关(计算敌人与玩家的距离)
    private float CaculatePlayerDistance() {
        float posX = myself_1.transform.position.x;
        float posZ = myself_1.transform.position.z;
        Vector3 playerPos = Player.transform.position + Player.GetComponent<CapsuleCollider>().center;
        float playerX = playerPos.x;
        float playerZ = playerPos.z;
        float distancePE = Mathf.Sqrt((playerX - posX) * (playerX - posX) + (playerZ - posZ) * (playerZ - posZ));
        return distancePE;
    }

    //怪物活着的时候该做的事情
    private void GhostAlive_() {
        if (status == 0 && distancePE_ > attackDistace)
        {
            GhostWalk_();
        }
        else if (status == 0 && distancePE_ <= attackDistace)
        {
            status = 1;
            GhostStand_();
        }
        else if (status == 1 && standTimer > 0f)
        {
            standTimer -= Time.deltaTime;
        }
        else if (status == 1 && standTimer <= 0f)
        {
            status = 2;
            GhostRun_();
        }
        else if (status == 2 && isTouched)
        {
            status = 3;
            GhostAttack_();
        }
    }


    private void OnCollisionEnter(Collision collision)
    {
        if (collision.collider.gameObject.tag == "Player")
        {
            isAttackedPlayer = true;
            isTouched = true;
        }
        else if (collision.collider.gameObject.tag == "shield")
        {
            isTouched = true;
            playerShield_ = GameObject.FindGameObjectWithTag("shield").GetComponent<LightShield>();
        }
    }

}