EnemyUnityExample

using UnityEngine;

[RequireComponent(typeof(Rigidbody2D))]
[RequireComponent(typeof(Health))]
public class Enemy : MonoBehaviour
{
    public static Enemy Create(Vector2 position)
    {
        var enemyPrefab = Resources.Load<Enemy>(nameof(Enemy));
        return Instantiate(enemyPrefab, position, Quaternion.identity);
    }

    [Header("Parameters")]
    [SerializeField] private float _speed;
    [SerializeField] private int _damage;
    [SerializeField] private float _targetMaxRadius;
    [SerializeField] private float _findTargetsCooldown;

    public Health Health { get; private set; }

    private Rigidbody2D _rigidbody;
    private Vector2 _target;

    private void Start()
    {
        Health = GetComponent<Health>();
        Health.OnDeadEvent += OnDead;

        _rigidbody = GetComponent<Rigidbody2D>();
        InvokeRepeating(nameof(LookForTargets), 0, _findTargetsCooldown);
    }
    private void OnDead() => Destroy(gameObject);

    private void FixedUpdate()
    {
        var direction = (_target - (Vector2)transform.position).normalized;
        _rigidbody.velocity = direction * _speed;
    }
    private void LookForTargets()
    {
        _target = Vector2.zero;

        var colliders = Physics2D.OverlapCircleAll(transform.position, _targetMaxRadius);
        foreach (var collider in colliders)
        {
            if (collider.TryGetComponent(out Building building))
            {
                var distance1 = Vector2.Distance(transform.position, _target);
                var distance2 = Vector2.Distance(transform.position, building.transform.position);
                if (distance1 > distance2)
                    _target = building.transform.position;
            }
        }
    }

    private void OnCollisionEnter2D(Collision2D collision)
    {
        if (collision.gameObject.TryGetComponent(out Building building))
        {
            building.Health.Damage(_damage);
            Destroy(gameObject);
        }
    }
}