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

public class MonsterController : MonoBehaviour
{
    public enum State
    {
        IDLE, TRACE, ATTACK, DIE
    }

    public State monsterState;
    public float attackDist = 2.0f;
    public float traceDist = 10.0f;

    public bool isDie = false;

    public Transform playerTr, monsterTr;

    private NavMeshAgent agent;
    private Animator animator;

    // Start is called before the first frame update
    void Start()
    {
        playerTr = GameObject.Find("Player").GetComponent<Transform>();
        monsterTr = transform;
        agent = GetComponent<NavMeshAgent>();
        animator = GetComponent<Animator>();

        StartCoroutine(CheckMonsterState());
        StartCoroutine(MonsterAction());
    }

    IEnumerator CheckMonsterState()
    {
        while (!isDie)
        {
            // 거리 계산
            float distance = Vector3.Distance(playerTr.position, monsterTr.position);

            if (distance <= attackDist)
            {
                monsterState = State.ATTACK;
            }
            else if (distance <= traceDist)
            {
                monsterState = State.TRACE;
            }
            else
            {
                monsterState = State.IDLE;
            }

            yield return new WaitForSeconds(0.3f);
        }
    }

    IEnumerator MonsterAction()
    {
        while (!isDie)
        {
            switch (monsterState)
            {
                case State.IDLE:
                    agent.isStopped = true;
                    animator.SetBool("IsTrace", false);
                    break;

                case State.TRACE:
                    // 추적 시작
                    agent.SetDestination(playerTr.position);
                    agent.isStopped = false;
                    animator.SetBool("IsAttack", false);
                    animator.SetBool("IsTrace", true);
                    break;

                case State.ATTACK:
                    animator.SetBool("IsAttack", true);
                    break;

                case State.DIE:
                    break;
            }

            yield return new WaitForSeconds(0.3f);
        }
    }

    void OnCollisionEnter(Collision coll)
    {
        if (coll.collider.CompareTag("BULLET"))
        {
            Destroy(coll.gameObject);
            animator.SetTrigger("Hit");
        }
    }
}