BABA_YAGA/Assets/Scripts/AI NPC/EnemyAI.cs

using System.Collections.Generic;
using UnityEngine;

public class EnemyAI : MonoBehaviour
{
    [Header("References")]
    public Transform player;

    [Header("Detection")]
    public float detectRange = 10f;
    public float moveSpeed = 3f;
    public float rotateSpeed = 50f;

    [Header("Artifact")]
    public bool playerHasArtifact;

    [Header("Laser")]
    public GameObject laserPrefab;
    public Transform firePoint;
    public float minShootDelay = 1f;
    public float maxShootDelay = 3f;

    private float nextShootTime;

    public Node behaviorTreeRoot;

    private void Start()
    {
        nextShootTime = Time.time + Random.Range(minShootDelay, maxShootDelay);
        InitBehaviorTree();
    }

    private void Update()
    {
        behaviorTreeRoot?.Evaluate();
    }

    private void InitBehaviorTree()
    {
        // Player có artifact -> focus + shoot
        var laserSequence = new Sequence(new List<Node>
        {
            new TaskNode(CheckHasArtifact),
            new TaskNode(ActionFocusAndShoot)
        });

        // Thấy player -> chạy tới
        var chaseSequence = new Sequence(new List<Node>
        {
            new TaskNode(CheckCanSeePlayer),
            new TaskNode(ActionMoveToPlayer)
        });

        // Không thấy ai -> scan
        var scanNode = new TaskNode(ActionRotationScan);

        behaviorTreeRoot = new Selector(new List<Node>
        {
            laserSequence,
            chaseSequence,
            scanNode
        });
    }

    #region CONDITIONS

    private NodeState CheckHasArtifact()
    {
        return playerHasArtifact
            ? NodeState.Success
            : NodeState.Failure;
    }

    private NodeState CheckCanSeePlayer()
    {
        if (player == null)
            return NodeState.Failure;

        float distance =
            Vector3.Distance(transform.position, player.position);

        if (distance <= detectRange)
        {
            return NodeState.Success;
        }

        return NodeState.Failure;
    }

    #endregion

    #region ACTIONS

    private NodeState ActionRotationScan()
    {
        Debug.Log("Scanning...");

        transform.Rotate(
            Vector3.up,
            rotateSpeed * Time.deltaTime);

        return NodeState.Running;
    }

    private NodeState ActionMoveToPlayer()
    {
        if (player == null)
            return NodeState.Failure;

        Debug.Log("Chasing Player");

        Vector3 dir =
            (player.position - transform.position).normalized;

        transform.position +=
            dir *
            moveSpeed *
            Time.deltaTime;

        return NodeState.Running;
    }

    private NodeState ActionFocusAndShoot()
    {
        if (player == null)
            return NodeState.Failure;

        // Focus player
        Vector3 dir =
            player.position - transform.position;

        dir.y = 0f;

        if (dir != Vector3.zero)
        {
            Quaternion targetRotation =
                Quaternion.LookRotation(dir);

            transform.rotation =
                Quaternion.Slerp(
                    transform.rotation,
                    targetRotation,
                    5f * Time.deltaTime);
        }

        // Shoot with random delay
        if (Time.time >= nextShootTime)
        {
            ShootLaser();

            nextShootTime =
                Time.time +
                Random.Range(minShootDelay, maxShootDelay);
        }

        return NodeState.Running;
    }

    private void ShootLaser()
    {
        if (laserPrefab == null || firePoint == null)
            return;

        Instantiate(
            laserPrefab,
            firePoint.position,
            firePoint.rotation);

        Debug.Log("Laser Shot!");
    }

    #endregion
}